02145nas a2200409 4500008004100000245007300041210006900114260001200183490000700195520089800202653005701100653003001157653002601187653001701213653002401230653002001254653001001274100002001284700002101304700001701325700002201342700001801364700002101382700001601403700002101419700001501440700001801455700002301473700001801496700002601514700002201540700002301562700002201585700002501607700001901632856008401651 2024 eng d00aBiogeographic survey of soil bacterial communities across Antarctica0 aBiogeographic survey of soil bacterial communities across Antarc c01/20240 v123 a

Antarctica and its unique biodiversity are increasingly at risk from the effects of global climate change and other human influences. A significant recent element underpinning strategies for Antarctic conservation has been the development of a system of Antarctic Conservation Biogeographic Regions (ACBRs). The datasets supporting this classification are, however, dominated by eukaryotic taxa, with contributions from the bacterial domain restricted to Actinomycetota and Cyanobacteriota. Nevertheless, the ice-free areas of the Antarctic continent and the sub-Antarctic islands are dominated in terms of diversity by bacteria. Our study aims to generate a comprehensive phylogenetic dataset of Antarctic bacteria with wide geographical coverage on the continent and sub-Antarctic islands, to investigate whether bacterial diversity and distribution is reflected in the current ACBRs.

10aAntarctic Conservation Biogeographic Regions (ACBRs)10aAntarctic soil microbiome10abioclimatic variables10abiogeography10amicrobial diversity10aregionalization10asoils1 aVarliero, Gilda1 aLebre, Pedro, H.1 aAdams, Byron1 aChown, Steven, L.1 aConvey, Peter1 aDennis, Paul, G.1 aFan, Dandan1 aFerrari, Belinda1 aFrey, Beat1 aHogg, Ian, D.1 aHopkins, David, W.1 aKong, Weidong1 aMakhalanyane, Thulani1 aMatcher, Gwynneth1 aNewsham, Kevin, K.1 aStevens, Mark, I.1 aWeigh, Katherine, V.1 aCowan, Don, A. uhttps://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-023-01719-302559nas a2200301 4500008004100000245008000041210006900121260001200190300001200202490000700214520166000221653001501881653001601896653002901912653001801941653001201959100002901971700001802000700002202018700002002040700002202060700001202082700001602094700002602110700002102136700003302157856006702190 2024 eng d00aSentinel protist taxa of the McMurdo Dry Valley lakes, Antarctica: A review0 aSentinel protist taxa of the McMurdo Dry Valley lakes Antarctica c03/2024 a13234720 v123 a

High-latitude meromictic lakes such as those in the Antarctic McMurdo Dry Valleys (MDV) harbor aquatic ecosystems dominated by the microbial loop. Within this habitat, which is limited year-round by light and nutrients, protists, or single celled eukaryotes, play outsized roles in the food web as the dominant primary producers and the apex predators. Thus, the MDV lake ecosystem represents an ideal system to study the role of sentinel protist taxa in carbon and nutrient cycling. The perennially ice-covered lakes are part of the McMurdo Long Term Ecological Research (McM LTER; mcmlter.org) established in 1993. In this review we will highlight the diversity and trophic roles of the MDV lake protist community and compare environmental factors driving spatiotemporal patterns in key protist taxa in two lakes within the McM LTER, Lakes Bonney and Fryxell. We will then discuss lessons learned from manipulated experiments on the impact of current and future climate-driven environmental change on sensitive protist taxa. Last, we will integrate knowledge gained from 25 years of lab-controlled experiments on key photosynthetic protists to extend our understanding of the function of these extremophiles within the MDV aquatic food webs. Our research group has studied the distribution and function of the MDV microbial community for nearly two decades, training the next generation of scientists to tackle future problems of these globally significant microbes. This review article will also highlight early career scientists who have contributed to this body of work and represent the future of scientific understanding in the Anthropocene.

10aAntarctica10aDisturbance10aMcMurdo Dry Valley lakes10aphytoplankton10aprotist1 aMorgan-Kiss, Rachael, M.1 aPopson, Devon1 aPereira, Rochelle1 aDolhi-Binder, J1 aTeufel, Amber, G.1 aLi, Wei1 aKalra, Isha1 aSherwell, Shasten, S.1 aReynebeau, Emily1 aTakacs-Vesbach, Cristina, D. uhttps://www.frontiersin.org/articles/10.3389/fevo.2024.132347201795nas a2200205 4500008004100000022001400041245009300055210006900148260001200217520099200229653002501221653001901246653002401265100002101289700002901310700002201339700001701361700001701378856019401395 2023 eng d a0260-305500aChange at 85 degrees south: Shackleton Glacier region proglacial lakes from 1960 to 20200 aChange at 85 degrees south Shackleton Glacier region proglacial  c05/20233 a

Over the last two decades, anomalous warming events have been observed in coastal Antarctic regions. While these events have been documented in the Ross Sea sector, the Antarctic interior is believed to have been buffered from warming. In this work, we present data from lakes located near Mt. Heekin and Thanksgiving Valley (~85° S) along the Shackleton Glacier, which are believed to be the southern-most Antarctic dry valley lakes. In 2018, the lakes were characterized, repeat satellite images were examined, and lake water chemistry was measured. Our analysis shows that lake areas recently increased, and the water-soluble ion chemistry indicates a flushing of salts from periglacial soils, likely from increased glacial melt as illustrated by water isotope data. Our results show that high southern latitude ice-free areas have likely been affected by warm pulses over the past 60 years and these pulses may be quasi-synchronous throughout the Transantarctic Mountains.

10aAntarctic glaciology10aclimate change10ameltwater chemistry1 aDiaz, Melisa, A.1 aGardner, Christopher, B.1 aElliot, David, H.1 aAdams, Byron1 aLyons, Berry uhttps://www.cambridge.org/core/journals/annals-of-glaciology/article/change-at-85-degrees-south-shackleton-glacier-region-proglacial-lakes-from-1960-to-2020/565D96AD7AE72BD22C49CCB772867AC402567nas a2200337 4500008004100000245010300041210006900144260001200213300000900225490000700234520158600241653001601827653001201843653001401855653001901869653001801888100002401906700002201930700002401952700002001976700002101996700002102017700002502038700002102063700002102084700001902105700002102124700001702145700002102162856004602183 2023 eng d00aThe distribution of surface soil moisture over space and time in eastern Taylor Valley, Antarctica0 adistribution of surface soil moisture over space and time in eas c06/2023 a31700 v153 a

Available soil moisture is thought to be the limiting factor for most ecosystem processes in the cold polar desert of the McMurdo Dry Valleys (MDVs) of Antarctica. Previous studies have shown that microfauna throughout the MDVs are capable of biological activity when sufficient soil moisture is available (~2–10% gravimetric water content), but few studies have attempted to quantify the distribution, abundance, and frequency of soil moisture on scales beyond that of traditional field work or local field investigations. In this study, we present our work to quantify the soil moisture content of soils throughout the Fryxell basin using multispectral satellite remote sensing techniques. Our efforts demonstrate that ecologically relevant abundances of liquid water are common across the landscape throughout the austral summer. On average, the Fryxell basin of Taylor Valley is modeled as containing 1.5 ± 0.5% gravimetric water content (GWC) across its non-fluvial landscape with ~23% of the landscape experiencing an average GWC > 2% throughout the study period, which is the observed limit of soil nematode activity. These results indicate that liquid water in the soils of the MDVs may be more abundant than previously thought, and that the distribution and availability of liquid water is dependent on both soil properties and the distribution of water sources. These results can also help to identify ecological hotspots in the harsh polar Antarctic environment and serve as a baseline for detecting future changes in the soil hydrological regime.

10aDry valleys10aecology10ahydrology10aremote sensing10asoil moisture1 aSalvatore, Mark, R.1 aBarrett, John, E.1 aFackrell, Laura, E.1 aSokol, Eric, R.1 aLevy, Joseph, S.1 aKuentz, Lily, C.1 aGooseff, Michael, N.1 aAdams, Byron, J.1 aPower, Sarah, N.1 aKnightly, Paul1 aMatul, Haley, M.1 aSzutu, Brian1 aDoran, Peter, T. uhttps://www.mdpi.com/2072-4292/15/12/317002259nas a2200289 4500008004100000245009100041210006900132260001200201490000600213520140100219653002301620653001601643653001401659653001001673653001801683100002401701700001701725700002101742700002601763700002601789700001701815700001701832700001801849700002001867700001801887856006401905 2023 eng d00aStrong dispersal limitation of microbial communities at Shackleton Glacier, Antarctica0 aStrong dispersal limitation of microbial communities at Shacklet c01/20230 v83 a

Microbial communities can be structured by both deterministic and stochastic processes, but the relative importance of these processes remains unknown. The ambiguity partly arises from an inability to disentangle soil microbial processes from confounding factors, such as aboveground plant communities or anthropogenic disturbance. In this study, we characterized the relative contributions of determinism and stochasticity to assembly processes of soil bacterial communities across a large environmental gradient of undisturbed Antarctic soils. We hypothesized that harsh soils would impose a strong environmental selection on microbial communities, whereas communities in benign soils would be structured largely by dispersal. Contrary to our expectations, dispersal was the dominant assembly mechanism across the entire soil environmental gradient, including benign environments. The microbial community composition reflects slowly changing soil conditions and dispersal limitation of isolated sites. Thus, stochastic processes, as opposed to deterministic, are primary drivers of soil ecosystem assembly across space at our study site. This is especially surprising given the strong environmental constraints on soil microorganisms in one of the harshest environments on the planet, suggesting that dispersal could be a driving force in microbial community assembly in soils worldwide.

10acommunity assembly10adeterminism10adispersal10aniche10astochasticity1 aLemoine, Nathan, P.1 aAdams, Byron1 aDiaz, Melisa, A.1 aDragone, Nicholas, B.1 aFranco, André, L. C.1 aFierer, Noah1 aLyons, Berry1 aHogg, Ian, D.1 aWall, Diana, H.1 aLurgi, Miguel uhttps://journals.asm.org/doi/full/10.1128/msystems.01254-2201137nas a2200193 4500008004100000245005600041210005300097260001200150300001100162490000700173520056500180100002100745700001800766700001400784700002300798700002900821700002600850856006700876 2022 eng d00aAn Antarctic alga that can survive the extreme cold0 aAntarctic alga that can survive the extreme cold c05/2022 a7408380 v103 a

Microscopic algae are tougher than you might think. Some can even survive the extreme cold. In this article, we describe one of the coolest algae of all, the Antarctic green alga called Chlamydomonas sp. UWO241. This one-celled super-organism lives deep in the frigid waters of a remote and permanently ice-covered lake in Antarctica. How does this little alga thrive in such a barren and unwelcoming place? Well, dive into this article to learn how studying the genome of UWO241 is helping scientists better understand this amazingly hardy alga.

1 aSmith, David, R.1 aLeung, Arthur1 aZhang, Xi1 aCvetkovska, Marina1 aMorgan-Kiss, Rachael, M.1 aHüner, Norman, P. A. uhttps://kids.frontiersin.org/articles/10.3389/frym.2022.74083802039nas a2200169 4500008004100000245013000041210007100171260001200242520142300254100002601677700001601703700001201719700002401731700002101755700002901776856006401805 2022 eng d00aAntarctic lake phytoplankton and bacteria from near‐surface waters exhibit high sensitivity to climate‐driven disturbance0 aAntarctic lake phytoplankton and bacteria from near‐surface wate c07/20223 a

The McMurdo Dry Valleys (MDVs), Antarctica, represent a cold, desert ecosystem poised on the threshold of melting and freezing water. The MDVs have experienced dramatic signs of climatic change, most notably a warm austral summer in 2001–2002 that caused widespread flooding, partial ice cover loss and lake level rise. To understand the impact of these climatic disturbances on lake microbial communities, we simulated lake level rise and ice-cover loss by transplanting dialysis-bagged communities from selected depths to other locations in the water column or to an open water perimeter moat. Bacteria and eukaryote communities residing in the surface waters (5 m) exhibited shifts in community composition when exposed to either disturbance, while microbial communities from below the surface were largely unaffected by the transplant. We also observed an accumulation of labile dissolved organic carbon in the transplanted surface communities. In addition, there were taxa-specific sensitivities: cryptophytes and Actinobacteria were highly sensitive particularly to the moat transplant, while chlorophytes and several bacterial taxa increased in relative abundance or were unaffected. Our results reveal that future climate-driven disturbances will likely undermine the stability and productivity of MDV lake phytoplankton and bacterial communities in the surface waters of this extreme environment.

1 aSherwell, Shasten, S.1 aKalra, Isha1 aLi, Wei1 aMcKnight, Diane, M.1 aPriscu, John, C.1 aMorgan-Kiss, Rachael, M. uhttps://onlinelibrary.wiley.com/doi/10.1111/1462-2920.1611301629nas a2200217 4500008004100000022001400041245007400055210006900129260001200198300001200210490000600222520097000228100002101198700002201219700002401241700001901265700002101284700002101305700001701326856006801343 2022 eng d a2378-224200aBarotropic seiches in a perennially ice-covered lake, East Antarctica0 aBarotropic seiches in a perennially icecovered lake East Antarct c02/2022 a26 - 330 v73 a

Water movement in ice-covered lakes is known to be driven by wind, sediment heat flux, solar radiation, saline density flows, and advective stream discharge. In large ice-covered lakes, wind-induced oscillations have been found to play a major role in horizontal flows. Here, we report recurrent, wind-driven, barotropic seiches in a small lake with a thick (4 m) permanent ice-cover. Between 2010 and 2016, we recorded 10.5- to 13-min oscillations of the hydrostatic water level in Lake Hoare, McMurdo Dry Valleys, East Antarctica, using pressure transducers moored to the lake bottom and suspended from the ice cover. Theoretical calculations showed a barotropic seiche should have a period of 12.6 min. Barotropic seiches were most frequent during high wind events (> 5 m s-1) in winter months (February–November). The period increased during summer months (December–January) when fast ice thinned and melted along the shoreline.

1 aCastendyk, Devin1 aDugan, Hilary, A.1 aGallagher, Hugh, A.1 aPujara, Nimish1 aDoran, Peter, T.1 aPriscu, John, C.1 aLyons, Berry uhttps://aslopubs.onlinelibrary.wiley.com/doi/10.1002/lol2.1022602367nas a2200289 4500008004100000245011400041210006900155260001200224300001400236490000600250520147700256653001501733653002201748653002201770653001001792100002601802700002401828700002701852700002101879700001801900700001701918700002001935700001701955700001701972700002401989856006402013 2022 eng d00aElevational constraints on the composition and genomic attributes of microbial communities in Antarctic soils0 aElevational constraints on the composition and genomic attribute c01/2022 ae01330-210 v73 a

The inland soils found on the Antarctic continent represent one of the more challenging environments for microbial life on Earth. Nevertheless, Antarctic soils harbor unique bacterial and archaeal (prokaryotic) communities able to cope with extremely cold and dry conditions. These communities are not homogeneous, and the taxonomic composition and functional capabilities (genomic attributes) of these communities across environmental gradients remain largely undetermined. We analyzed the prokaryotic communities in soil samples collected from across the Shackleton Glacier region of Antarctica by coupling quantitative PCR, marker gene amplicon sequencing, and shotgun metagenomic sequencing. We found that elevation was the dominant factor explaining differences in the structures of the soil prokaryotic communities, with the drier and saltier soils found at higher elevations harboring less diverse communities and unique assemblages of cooccurring taxa. The higher-elevation soil communities also had lower maximum potential growth rates (as inferred from metagenome-based estimates of codon usage bias) and an overrepresentation of genes associated with trace gas metabolism. Together, these results highlight the utility of assessing community shifts across pronounced environmental gradients to improve our understanding of the microbial diversity found in Antarctic soils and the strategies used by soil microbes to persist at the limits of habitability.

10aAntarctica10amicrobial ecology10asoil microbiology10asoils1 aDragone, Nicholas, B.1 aHenley, Jessica, B.1 aHolland-Moritz, Hannah1 aDiaz, Melisa, A.1 aHogg, Ian, D.1 aLyons, Berry1 aWall, Diana, H.1 aAdams, Byron1 aFierer, Noah1 aMackelprang, Rachel uhttps://journals.asm.org/doi/full/10.1128/msystems.01330-2102315nas a2200265 4500008004100000245009400041210006900135260001200204520148400216653001501700653001701715653002601732653001901758653001701777653001301794653002301807100002101830700002601851700002201877700002401899700002301923700002001946700002501966856005801991 2022 eng d00aIslands in the ice: Potential impacts of habitat transformation on Antarctic biodiversity0 aIslands in the ice Potential impacts of habitat transformation o c07/20223 a

Antarctic biodiversity faces an unknown future with a changing climate. Most terrestrial biota is restricted to limited patches of ice-free land in a sea of ice, where they are adapted to the continent's extreme cold and wind and exploit microhabitats of suitable conditions. As temperatures rise, ice-free areas are predicted to expand, more rapidly in some areas than others. There is high uncertainty as to how species' distributions, physiology, abundance, and survivorship will be affected as their habitats transform. Here we use current knowledge to propose hypotheses that ice-free area expansion (i) will increase habitat availability, though the quality of habitat will vary; (ii) will increase structural connectivity, although not necessarily increase opportunities for species establishment; (iii) combined with milder climates will increase likelihood of non-native species establishment, but may also lengthen activity windows for all species; and (iv) will benefit some species and not others, possibly resulting in increased homogeneity of biodiversity. We anticipate considerable spatial, temporal, and taxonomic variation in species responses, and a heightened need for interdisciplinary research to understand the factors associated with ecosystem resilience under future scenarios. Such research will help identify at-risk species or vulnerable localities and is crucial for informing environmental management and policymaking into the future.

10aAntarctica10abiodiversity10abiotic homogenization10aclimate change10aconnectivity10aice-free10anon-native species1 aLee, Jasmine, R.1 aWaterman, Melinda, J.1 aShaw, Justine, D.1 aBergstrom, Dana, M.1 aLynch, Heather, J.1 aWall, Diana, H.1 aRobinson, Sharon, A. uhttps://onlinelibrary.wiley.com/doi/10.1111/gcb.1633102431nas a2200277 4500008004100000022001300041245008500054210006900139260001200208300001100220490000800231520163400239653001501873653001301888653001401901653001901915653001901934653001901953100001401972700001201986700002501998700002102023700001702044700001602061856007602077 2022 eng d a0048969700aOrganic matter distribution in the icy environments of Taylor Valley, Antarctica0 aOrganic matter distribution in the icy environments of Taylor Va c10/2022 a1566390 v8413 a

Glaciers can accumulate and release organic matter affecting the structure and function of associated terrestrial and aquatic ecosystems. We analyzed 18 ice cores collected from six locations in Taylor Valley (McMurdo Dry Valleys), Antarctica to determine the spatial abundance and quality of organic matter, and the spatial distribution of bacterial density and community structure from the terminus of the Taylor Glacier to the coast (McMurdo Sound). Our results showed that dissolved and particulate organic carbon (DOC and POC) concentrations in the ice core samples increased from the Taylor Glacier to McMurdo Sound, a pattern also shown by bacterial cell density. Fluorescence Excitation Emission Matrices Spectroscopy (EEMs) and multivariate parallel factor (PARAFAC) modeling identified one humic-like (C1) and one protein-like (C2) component in ice cores whose fluorescent intensities all increased from the Polar Plateau to the coast. The fluorescence index showed that the bioavailability of dissolved organic matter (DOM) also decreased from the Polar Plateau to the coast. Partial least squares path modeling analysis revealed that bacterial abundance was the main positive biotic factor influencing both the quantity and quality of organic matter. Marine aerosol influenced the spatial distribution of DOC more than katabatic winds in the ice cores. Certain bacterial taxa showed significant correlations with DOC and POC concentrations. Collectively, our results show the tight connectivity among organic matter spatial distribution, bacterial abundance and meteorology in the McMurdo Dry Valley ecosystem.

10aAntarctica10abacteria10aice cores10akatabatic wind10amarine aerosol10aorganic matter1 aGuo, Bixi1 aLi, Wei1 aSantibáñez, Pamela1 aPriscu, John, C.1 aLiu, Yongqin1 aLiu, Keshao uhttps://www.sciencedirect.com/science/article/abs/pii/S004896972203736602944nas a2200301 4500008004100000022001400041245009600055210007100151260001200222490000700234520204100241653001702282653001902299653002002318653001402338653002302352653002302375100002602398700001702424700002102441700002402462700002602486700001702512700001702529700001802546700002002564856005802584 2022 eng d a1354-101300aResponse of Antarctic soil fauna to climate‐driven changes since the Last Glacial Maximum0 aResponse of Antarctic soil fauna to climate‐driven changes since c01/20220 v283 a

Understanding how terrestrial biotic communities have responded to glacial recession since the Last Glacial Maximum (LGM) can inform present and future responses of biota to climate change. In Antarctica, the Transantarctic Mountains (TAM) have experienced massive environmental changes associated with glacial retreat since the LGM, yet we have few clues as to how its soil invertebrate-dominated animal communities have responded. Here, we surveyed soil invertebrate fauna from above and below proposed LGM elevations along transects located at 12 features across the Shackleton Glacier region. Our transects captured gradients of surface ages possibly up to 4.5 million years and the soils have been free from human disturbance for their entire history. Our data support the hypothesis that soils exposed during the LGM are now less suitable habitats for invertebrates than those that have been exposed by deglaciation following the LGM. Our results show that faunal abundance, community composition, and diversity were all strongly affected by climate-driven changes since the LGM. Soils more recently exposed by glacial recession (as indicated by distances from present ice surfaces) had higher faunal abundances and species richness than older exposed soils. Higher abundances of the dominant nematode Scottnema were found in older exposed soils, while Eudorylaimus, Plectus, tardigrades, and rotifers preferentially occurred in more recently exposed soils. Approximately 30% of the soils from which invertebrates could be extracted had only Scottnema, and these single-taxon communities occurred more frequently in soils exposed for longer periods of time. Our structural equation modeling of abiotic drivers highlighted soil salinity as a key mediator of Scottnema responses to soil exposure age. These changes in soil habitat suitability and biotic communities since the LGM indicate that Antarctic terrestrial biodiversity throughout the TAM will be highly altered by climate warming.

10abiodiversity10aclimate change10aglacial retreat10anematodes10aShackleton Glacier10asoil invertebrates1 aFranco, André, L. C.1 aAdams, Byron1 aDiaz, Melisa, A.1 aLemoine, Nathan, P.1 aDragone, Nicholas, B.1 aFierer, Noah1 aLyons, Berry1 aHogg, Ian, D.1 aWall, Diana, H. uhttps://onlinelibrary.wiley.com/doi/10.1111/gcb.1594002175nas a2200229 4500008004100000022001400041245022200055210006900277260001200346300001400358490000700372520135100379653001501730653001601745653001901761653001601780653001201796100002101808700002101829700002401850856007101874 2022 eng d a1523-043000aTiming and duration of ephemeral Antarctic water tracks and wetlands using high temporal–resolution satellite imagery, high spatial–resolution satellite imagery, and ground-based sensors in the McMurdo Dry Valleys0 aTiming and duration of ephemeral Antarctic water tracks and wetl c12/2022 a538 - 5610 v543 a

Antarctic water tracks and ephemeral wetlands are a primary location for biogeochemical soil processes driving cold desert soil formation. Though the spatial extent of water tracks and wetted soils has been mapped in the McMurdo Dry Valleys (MDV) on the basis of mapping darkened pixels in high-resolution commercial satellite imagery, the timescale over which water tracks and wetlands form and the duration of these biogeochemically active environments remain unknown. Here, we determine the start date and end dates and the duration of wetted soils at ten sites located across the MDV using a combination of in situ soil sensors and two complementary remote imaging platforms (Planet and WorldView) to understand the hydroclimatic processes that drive water track and wetland formation. Our remote sensing employs a terrain correction workflow that removes the contribution of differential direct illumination and small-scale shadowing on pixel brightness, reducing false positives (soils identified as wetted when in fact they are shadowed or darkened as a consequence of high phase angle). Our findings extend the water track and wetland hydroperiod by over a month, showing darkening occurring from November to March, suggesting hydrological contributions from ground ice thaw, snowmelt, and salt deliquescence and soil brine growth.

10aAntarctica10ahydroperiod10aremote sensing10awater track10awetland1 aKuentz, Lily, C.1 aLevy, Joseph, S.1 aSalvatore, Mark, R. uhttps://www.tandfonline.com/doi/full/10.1080/15230430.2022.212385802600nas a2200217 4500008004100000245010600041210006900147260001200216490000700228520191500235653001502150653001802165653001602183653002202199653001702221100002202238700001702260700002102277700001702298856006702315 2021 eng d00aAntarctic water tracks: Microbial community responses to variation in soil moisture, pH, and salinity0 aAntarctic water tracks Microbial community responses to variatio c01/20210 v123 a

Ice-free soils in the McMurdo Dry Valleys select for taxa able to cope with challenging environmental conditions, including extreme chemical water activity gradients, freeze-thaw cycling, desiccation, and solar radiation regimes. The low biotic complexity of Dry Valley soils makes them well suited to investigate environmental and spatial influences on bacterial community structure. Water tracks are annually wetted habitats in the cold-arid soils of Antarctica that form briefly each summer with moisture sourced from snow melt, ground ice thaw, and atmospheric deposition via deliquescence and vapor flow into brines. Compared to neighboring arid soils, water tracks are highly saline and relatively moist habitats. They represent a considerable area (∼5–10 km2) of the Dry Valley terrestrial ecosystem, an area that is expected to increase with ongoing climate change. The goal of this study was to determine how variation in the environmental conditions of water tracks influences the composition and diversity of microbial communities. We found significant differences in microbial community composition between on- and off-water track samples, and across two distinct locations. Of the tested environmental variables, soil salinity was the best predictor of community composition, with members of the Bacteroidetes phylum being relatively more abundant at higher salinities and the Actinobacteria phylum showing the opposite pattern. There was also a significant, inverse relationship between salinity and bacterial diversity. Our results suggest water track formation significantly alters dry soil microbial communities, likely influencing subsequent ecosystem functioning. We highlight how Dry Valley water tracks could be a useful model system for understanding the potential habitability of transiently wetted environments found on the surface of Mars.

10aAntarctica10aextremophiles10aMars analog10amicrobial ecology10awater tracks1 aGeorge, Scott, F.1 aFierer, Noah1 aLevy, Joseph, S.1 aAdams, Byron uhttps://www.frontiersin.org/articles/10.3389/fmicb.2021.61673002885nas a2200241 4500008004100000245006300041210006200104260004100166300001200207520209300219653003102312653003602343653002402379653001902403653002402422100001602446700001702462700002302479700001702502700002402519700002502543856007502568 2021 eng d00aChemical weathering in the McMurdo Dry Valleys, Antarctica0 aChemical weathering in the McMurdo Dry Valleys Antarctica aHoboken, NJbJohn Wiley & Sons, Inc. a205-2163 a

While chemical weathering has not always been considered an active process in the McMurdo Dry Valleys (MDV), Antarctica, long‐term geochemical and hydrological investigations have provided an overall better understanding of chemical weathering in this polar desert environment. Liquid water on the landscape is limited to stream channels as well as shallow subsurface melt features, as there is no overland flow. Stream total suspended sediment loads are low, with the sources of sediment from stream channels, aeolian input, and/or from the surfaces of glaciers. MDV soils contain high concentrations of soluble salts with little clay material, but since absent of water, these soils are a minimal location of chemical weathering. Hyporheic zones exchange water during streamflow, and these areas control the stream geochemistry over various temporal scales. Hyporheic zones promote rapid aluminosilicate weathering by moving dilute glacial meltwater into intimate contact with sediment surfaces. Rapid weathering of the aluminosilicates in the streambed and hyporheic zones is the most plausible explanation for chemostasis observed in these streams, indicating that little to no catchment processes are necessary to explain the observed chemostasis in the MDV. Shallow subsurface waters with distinct geochemical signatures have much higher dissolved Si concentrations than the stream waters and indicate that they are responsible for enhanced aluminosilicate weathering in this polar desert environment. The dissolution of CaCO3 is also a major process in the hyporheic zones as generally the streams are unsaturated with respect to calcite. Cation‐exchange reactions are also important in the evolution from Na‐Cl brines to Ca‐Cl brines within the soil column, while authigenic CaCO3 can both dissolve and precipitate depending on the condition of the system. Recently, stream channel landscapes are changing due to the melting of buried ice, creating thermokarst and water track features, resulting in a sediment and solute influx to the stream.

10aaluminosilicate weathering10aCaCO3 dissolution/precipitation10achemical weathering10ahyporheic zone10aMcMurdo Dry Valleys1 aHunt, Allen1 aEgli, Markus1 aFaybishenko, Boris1 aLyons, Berry1 aLeslie, Deborah, L.1 aGooseff, Michael, N. uhttps://agupubs.onlinelibrary.wiley.com/doi/10.1002/9781119563952.ch1102809nas a2200337 4500008004100000245012000041210006900161260001200230300001800242490000800260520168500268653002201953653002001975653004901995653001902044653001202063653004302075653001902118653002402137653002102161653003102182100002102213700002402234700002202258700002402280700002402304700002502328700002402353700002502377856006902402 2021 eng d00aDiatoms in hyporheic sediments trace organic matter retention and processing in the McMurdo Dry Valleys, Antarctica0 aDiatoms in hyporheic sediments trace organic matter retention an c02/2021 ae2020JG0060970 v1263 a

In low‐nutrient streams in cold and arid ecosystems, the spiraling of autochthonous particulate organic matter (POM) may provide important nutrient subsidies downstream. Because of its lability and the spatial heterogeneity of processing in hyporheic sediments, the downstream transport and fate of autochthonous POM can be difficult to trace. In Antarctic McMurdo Dry Valley (MDV) streams, any POM retained in the hyporheic zone is expected to be derived from surface microbial mats that contain diatoms with long‐lasting silica frustules. We tested whether diatom frustules can be used to trace the retention of autochthonous POM in the hyporheic zone and whether certain geomorphic locations promote this process. The accumulation of diatom frustules in hyporheic sediments, measured as biogenic silica, was correlated with loss‐on‐ignition organic matter and sorbed ammonium, suggesting that diatoms can be used to identify locations where POM has been retained and processed over long timescales, regardless of whether the POM remains intact. In addition, by modeling the upstream sources of hyporheic diatom assemblages, we found that POM was predominantly derived from N‐fixing microbial mats of the genus Nostoc. In terms of spatial variability, we conclude that the hyporheic sediments adjacent to the stream channel that are regularly inundated by daily flood pulses are where the most POM has been retained over long timescales. Autochthonous POM is retained in hyporheic zones of low‐nutrient streams beyond the MDVs, and we suggest that biogenic silica and diatom composition can be used to identify locations where this transfer is most prevalent.

10abenthic processes10abiogenic silica10abiogeochemical cycles processes and modeling10acarbon cycling10adiatoms10agroundwater/surface water interactions10ahyporheic zone10aMcMurdo Dry Valleys10anitrogen cycling10aparticulate organic matter1 aHeindel, Ruth, C1 aDarling, Joshua, P.1 aSingley, Joel, G.1 aBergstrom, Anna, J.1 aMcKnight, Diane, M.1 aLukkari, Braeden, M.1 aWelch, Kathleen, A.1 aGooseff, Michael, N. uhttps://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JG00609702093nas a2200205 4500008004100000022001400041245013400055210006900189260001200258300000900270520139200279653001801671653001401689653001701703653002101720653001301741653001901754100002101773856009301794 2021 eng d a0954-102000aEpisodic basin-scale soil moisture anomalies associated with high relative humidity events in the McMurdo Dry Valleys, Antarctica0 aEpisodic basinscale soil moisture anomalies associated with high c08/2021 a1-153 a

Outside of hydrologically wetted active layer soils and humidity-sensitive soil brines, low soil moisture is a limiting factor controlling biogeochemical processes in the McMurdo Dry Valleys. But anecdotal field observations suggest that episodic wetting and darkening of surface soils in the absence of snowmelt occurs during high humidity conditions. Here, I analyse long-term meteorological station data to determine whether soil-darkening episodes are present in the instrumental record and whether they are, in fact, correlated with relative humidity. A strong linear correlation is found between relative humidity and soil reflectance at the Lake Bonney long-term autonomous weather station. Soil reflectance is found to decrease annually by a median of 27.7% in response to high humidity conditions. This magnitude of darkening is consistent with soil moisture rising from typical background values of < 0.5 wt.% to 2–3 wt.%, suggesting that regional atmospheric processes may result in widespread soil moisture generation in otherwise dry surface soils. Temperature and relative humidity conditions under which darkening is observed occur for hundreds of hours per year, but are dominated by episodes occurring between midnight and 07h00 local time, suggesting that wetting events may be common, but are not widely observed during typical diel science operations.

10adeliquescence10ahydrology10amicroclimate10amicrometeorology10apedology10aremote sensing1 aLevy, Joseph, S. uhttps://www.cambridge.org/core/product/identifier/S0954102021000341/type/journal_article02506nas a2200289 4500008004100000022001400041245006300055210006300118260001200181490000800193520169900201653001501900653001701915653001301932653001801945653001001963653001001973100002601983700002102009700001802030700001702048700002002065700002002085700002102105700001702126856007302143 2021 eng d a2169-895300aExploring the boundaries of microbial habitability in soil0 aExploring the boundaries of microbial habitability in soil c06/20210 v1263 a

Microbes are widely assumed to be capable of colonizing even the most challenging terrestrial surface environments on Earth given enough time. We would not expect to find surface soils uninhabited by microbes as soils typically harbor diverse microbial communities and viable microbes have been detected in soils exposed to even the most inhospitable conditions. However, if uninhabited soils do exist, we might expect to find them in Antarctica. We analyzed 204 ice-free soils collected from across a remote valley in the Transantarctic Mountains (84–85°S, 174–177°W) and were able to identify a potential limit of microbial habitability. While most of the soils we tested contained diverse microbial communities, with fungi being particularly ubiquitous, microbes could not be detected in many of the driest, higher elevation soils—results that were confirmed using cultivation-dependent, cultivation-independent, and metabolic assays. While we cannot confirm that this subset of soils is completely sterile and devoid of microbial life, our results suggest that microbial life is severely restricted in the coldest, driest, and saltiest Antarctic soils. Constant exposure to these conditions for thousands of years has limited microbial communities so that their presence and activity is below detectable limits using a variety of standard methods. Such soils are unlikely to be unique to the studied region with this work supporting previous hypotheses that microbial habitability is constrained by near-continuous exposure to cold, dry, and salty conditions, establishing the environmental conditions that limit microbial life in terrestrial surface soils.

10aAntarctica10aastrobiology10abacteria10aextremophiles10afungi10asoils1 aDragone, Nicholas, B.1 aDiaz, Melisa, A.1 aHogg, Ian, D.1 aLyons, Berry1 aJackson, Andrew1 aWall, Diana, H.1 aAdams, Byron, J.1 aFierer, Noah uhttps://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020JG00605202615nas a2200229 4500008004100000245011400041210006900155260001200224300001600236490000700252520188900259100002102148700002902169700002102198700002002219700002102239700002002260700001802280700001702298700001702315856005302332 2021 eng d00aGeochemical zones and environmental gradients for soils from the central Transantarctic Mountains, Antarctica0 aGeochemical zones and environmental gradients for soils from the c03/2021 a1629 - 16440 v183 a

Previous studies have established links between biodiversity and soil geochemistry in the McMurdo Dry Valleys, Antarctica, where environmental gradients are important determinants of soil biodiversity. However, these gradients are not well established in the central Transantarctic Mountains, which are thought to represent some of the least hospitable Antarctic soils. We analyzed 220 samples from 11 ice-free areas along the Shackleton Glacier (~85°S), a major outlet glacier of the East Antarctic Ice Sheet. We established three zones of distinct geochemical gradients near the head of the glacier (upper), its central part (middle), and at the mouth (lower). The upper zone had the highest water-soluble salt concentrations with total salt concentrations exceeding 80 000 µg g-1, while the lower zone had the lowest water-soluble N:P ratios, suggesting that, in addition to other parameters (such as proximity to water and/or ice), the lower zone likely represents the most favorable ecological habitats. Given the strong dependence of geochemistry on geographic parameters, we developed multiple linear regression and random forest models to predict soil geochemical trends given latitude, longitude, elevation, distance from the coast, distance from the glacier, and soil moisture (variables which can be inferred from remote measurements). Confidence in our random forest model predictions was moderately high with R2 values for total water-soluble salts, water-soluble N:P, ClO4-, and ClO3- of 0.81, 0.88, 0.78, and 0.74, respectively. These modeling results can be used to predict geochemical gradients and estimate salt concentrations for other Transantarctic Mountain soils, information that can ultimately be used to better predict distributions of soil biota in this remote region.

1 aDiaz, Melisa, A.1 aGardner, Christopher, B.1 aWelch, Susan, A.1 aJackson, Andrew1 aAdams, Byron, J.1 aWall, Diana, H.1 aHogg, Ian, D.1 aFierer, Noah1 aLyons, Berry uhttps://bg.copernicus.org/articles/18/1629/2021/02603nas a2200181 4500008004100000245007200041210006900113260001200182300001200194490000800206520196600214100002402180700002402204700001702228700002402245700002402269856012802293 2021 eng d00aGeochemistry of contrasting stream types, Taylor Valley, Antarctica0 aGeochemistry of contrasting stream types Taylor Valley Antarctic c01/2021 a425-4480 v1333 a

The McMurdo Dry Valley region is the largest ice-free area of Antarctica. Ephemeral streams flow here during the austral summer, transporting glacial meltwater to perennially ice-covered, closed basin lakes. The chemistry of 24 Taylor Valley streams was examined over the two-decade period of monitoring from 1993 to 2014, and the geochemical behavior of two streams of contrasting physical and biological character was monitored across the seven weeks of the 2010–2011 flow season. Four species dominate stream solute budgets: HCO3, Ca2+, Na+, and Cl, with SO42–, Mg2+, and K+ present in significantly lesser proportions. All streams contain dissolved silica at low concentrations. Across Taylor Valley, streams are characterized by their consistent anionic geochemical fingerprint of HCO3 > Cl > SO4, but there is a split in cation composition between 14 streams with Ca > Na > Mg > K and 10 streams with Na > Ca > Mg > K.


Andersen Creek is a first-order proglacial stream representative of the 13 short streams that flow <1.5 km from source to gage. Von Guerard is representative of 11 long streams 2–7 km in length characterized by extensive hyporheic zones. Both streams exhibit a strong daily cycle for solute load, temperature, dissolved oxygen, and pH, which vary in proportion to discharge. A well-expressed diurnal co-variation of pH with dissolved oxygen is observed for both streams that reflects different types of biological control. The relative consistency of Von Guerard composition over the summer flow season reflects chemostatic regulation, where water in transient storage introduced during times of high streamflow has an extended opportunity for water-sediment interaction, silicate mineral dissolution, and pore-water exchange.

1 aHarmon, Russell, S.1 aLeslie, Deborah, L.1 aLyons, Berry1 aWelch, Kathleen, A.1 aMcKnight, Diane, M. uhttps://pubs.geoscienceworld.org/gsa/gsabulletin/article/133/1-2/425/587799/Geochemistry-of-contrasting-stream-types-Taylor01707nam a2200205 4500008004100000020001800041245013400059210006900193260001300262520102300275653001501298653001701313653001201330653001201342653001801354653000901372100002401381700002101405856007501426 2021 eng d a978012820245600aThe McMurdo Dry Valleys of Antarctica: A geological, environmental, and ecological analog to the Martian surface and near surface0 aMcMurdo Dry Valleys of Antarctica A geological environmental and bElsevier3 a

The surface of Mars is universally thought to have experienced widespread cold and dry environmental conditions for at least the last half of its geologic history, with more modern studies suggesting relatively cold and dry conditions early in its geologic history as well. However, the paucity of liquid water and mean annual temperatures well below the freezing point of water do not necessarily mean a complete cessation of all water-related geologic activity at the Martian surface. Over the past several decades, investigations in the McMurdo Dry Valleys (MDV) of Antarctica have revealed a dynamic geological, environmental, and ecological system resulting from locally optimized conditions operating over repeated, albeit brief, intervals during summer months. In this chapter, we compare the hyper-arid and hypo-thermal environments of the MDV and the modern Martian surface and discuss three unique enigmas that demonstrate how the Antarctic is a valuable analog to better understand processes on Mars.

10aAntarctica10aastrobiology10aclimate10ageology10ageomorphology10aMars1 aSalvatore, Mark, R.1 aLevy, Joseph, S. uhttps://www.sciencedirect.com/science/article/pii/B978012820245600011202224nas a2200229 4500008004100000245016400041210006900205260001200274300000800286490000700294520144700301100002401748700002301772700002201795700001501817700002101832700002201853700002201875700003201897700002101929856004401950 2021 eng d00aMetabolic capacity of the Antarctic cyanobacterium Phormidium pseudopriestleyi that sustains oxygenic photosynthesis in the presence of hydrogen sulfide0 aMetabolic capacity of the Antarctic cyanobacterium IPhormidium p c03/2021 a4260 v123 a

Sulfide inhibits oxygenic photosynthesis by blocking electron transfer between H2O and the oxygen-evolving complex in the D1 protein of Photosystem II. The ability of cyanobacteria to counter this effect has implications for understanding the productivity of benthic microbial mats in sulfidic environments throughout Earth history. In Lake Fryxell, Antarctica, the benthic, filamentous cyanobacterium Phormidium pseudopriestleyi creates a 1–2 mm thick layer of 50 µmol L−1 O2 in otherwise sulfidic water, demonstrating that it sustains oxygenic photosynthesis in the presence of sulfide. A metagenome-assembled genome of P. pseudopriestleyi indicates a genetic capacity for oxygenic photosynthesis, including multiple copies of psbA (encoding the D1 protein of Photosystem II), and anoxygenic photosynthesis with a copy of sqr (encoding the sulfide quinone reductase protein that oxidizes sulfide). The genomic content of P. pseudopriestleyi is consistent with sulfide tolerance mechanisms including increasing psbA expression or directly oxidizing sulfide with sulfide quinone reductase. However, the ability of the organism to reduce Photosystem I via sulfide quinone reductase while Photosystem II is sulfide-inhibited, thereby performing anoxygenic photosynthesis in the presence of sulfide, has yet to be demonstrated. 

1 aLumian, Jessica, E.1 aJungblut, Anne, D.1 aDillon, Megan, L.1 aHawes, Ian1 aDoran, Peter, T.1 aMackey, Tyler, J.1 aDick, Gregory, J.1 aGrettenberger, Christen, L.1 aSumner, Dawn, Y. uhttps://www.mdpi.com/2073-4425/12/3/42602509nas a2200205 4500008004100000245012600041210006900167260005300236490000900289520180200298653002502100653001502125653001702140653002402157653002002181653002302201100002502224700001702249856003702266 2020 eng d00aAnalysis of acid-leachable barium, copper, iron, lead, & zinc concentrations in Taylor Valley, Antarctic stream sediments0 aAnalysis of acidleachable barium copper iron lead zinc concentra aColumbus, OHbThe Ohio State Universityc05/20200 vB.S.3 a

The purpose of this study is to assess the concentrations of Barium (Ba), Copper (Cu), Iron (Fe), Lead (Pb), and Zinc (Zn) in sediment samples obtained from the Wales and Commonwealth streams located in Taylor Valley, Antarctica. These samples were collected at seven sample sites (three in Wales Glacier and four in Commonwealth Glacier) in 0 to 2 cm, 2 to 4 cm, 4 to 6 cm, and 6 to 8 cm depth increments which resulted in 28 total samples. After the collection process, these samples underwent a volumetric 1:5 sediment: 10% HCl leach for 48 hours, filtration through 4-µm pore-size, cellulose acetate membrane filters, and inductively coupled plasma mass spectrometry (ICP-MS) analyses in the Trace Element Research Laboratory at The Ohio State University. Upon completion of the analyses, results showed that the Wales samples had a higher average concentration of every metal element overall and at each depth increment when compared to the Commonwealth samples. In addition to the weak-acid leachate metal analyses, a second aliquot of one sediment profile from each stream was analyzed at Villanova University for the 210Pb activity via gamma spectroscopy. This was done to estimate the sedimentation rates at each of these sites. From the sedimentation rates, sedimentation fluxes were calculated for each element for each sediment profile at each of these sites. The data demonstrated that Fe is the most abundant element while Pb is the least abundant. Lastly, upon examination of results, it was found that the concentrations of these metals are often higher in samples collected closer to the surface. These findings suggest these streams, and their sources, have had little, if any, impact by anthropogenic input of metals, and that metal fluxes to the sediments are low.

10aacid-leachable metal10aAntarctica10ageochemistry10aMcMurdo Dry Valleys10apolar sediments10asedimentation rate1 aPiergallini, Brianna1 aLyons, Berry uhttp://hdl.handle.net/1811/9177201971nas a2200181 4500008004100000245008500041210006900126260005200195520137400247100002101621700002101642700001801663700002101681700001301702700002001715700002001735856003401755 2020 eng d00aFollowing the Astrobiology Roadmap: Origins, Habitability and Future Exploration0 aFollowing the Astrobiology Roadmap Origins Habitability and Futu aNorfolk, United KingdombCaister Academic Press3 a

Astrobiology asks three fundamental questions as outlined by the NASA Astrobiology Roadmap: 1. How did Life begin and evolve?; Is there Life elsewhere in the Universe?; and, What is the future of Life on Earth? As we gain perspective on how Life on Earth arose and adapted to its many niches, we too gain insight into how a planet achieves habitability. Here on Earth, microbial Life has evolved to exist in a wide range of habitats from aquatic systems to deserts, the human body, and the International Space Station (ISS). Landers, rovers, and orbiter missions support the search for signatures of Life beyond Earth, by generating data on surface and subsurface conditions of other worlds. These have provided evidence for water activity, supporting the potential for extinct or extant Life. To investigate the putative ecologies of these systems, we study extreme environments on Earth. Several locations on our planet provide analog settings to those we have detected or expect to find on neighboring and distant worlds. Whereas, the field of space biology uses the ISS and low gravity analogs to gain insight on how transplanted Earth-evolved organisms will respond to extraterrestrial environments. Modern genomics allows us to chronicle the genetic makeup of such organisms and provides an understanding of how Life adapts to various extreme environments.

1 aO'Rourke, Aubrie1 aZoumplis, Angela1 aWilburn, Paul1 aLee, Michael, D.1 aLee, Zhi1 aVecina, Marissa1 aMercader, Kysha uhttps://www.caister.com/astro02303nas a2200265 4500008004100000245012500041210006900166260001200235520144100247653001901688653002001707653002001727653001901747653002901766100002301795700001801818700001801836700002501854700001901879700001701898700001701915700002001932700002401952856006101976 2020 eng d00aGenetic diversity of soil invertebrates corroborates timing estimates for past collapses of the West Antarctic Ice Sheet0 aGenetic diversity of soil invertebrates corroborates timing esti c08/20203 a

During austral summer field seasons between 1999 and 2018, we sampled at 91 locations throughout southern Victoria Land and along the Transantarctic Mountains for six species of endemic microarthropods (Collembola), covering a latitudinal range from 76.0°S to 87.3°S. We assembled individual mitochondrial cyto-chrome c oxidase subunit 1 (COI) sequences (n = 866) and found high levels of sequence divergence at both small (<10 km) and large (>600 km) spatial scales for four of the six Collembola species. We applied molecular clock estimates and assessed genetic divergences relative to the timing of past glacial cycles, including collapses of the West Antarctic Ice Sheet (WAIS). We found that genetically distinct lineages within three species have likely been isolated for at least 5.54 My to 3.52 My, while the other three species diverged more recently (<2 My). We suggest that Collembola had greater dispersal opportunities under past warmer climates, via flotation along coastal margins. Similarly increased opportunities for dispersal may occur under contemporary climate warming scenarios, which could influence the genetic structure of extant populations. As Collembola are a living record of past landscape evolution within Antarctica, these findings provide biological evidence to support geological and glaciological estimates of historical WAIS dynamics over the last ca. 5 My.

10aclimate change10amicroarthropods10amolecular clock10aphylogeography10aterrestrial biodiversity1 aCollins, Gemma, E.1 aHogg, Ian, D.1 aConvey, Peter1 aSancho, Leopoldo, G.1 aCowan, Don, A.1 aLyons, Berry1 aAdams, Byron1 aWall, Diana, H.1 aGreen, T., G. Allan uhttps://www.pnas.org/content/early/2020/08/19/200792511702540nas a2200289 4500008004100000245012600041210006900167260001200236490000800248520163000256653002101886653001501907653001701922653001501939653002401954653001901978100002101997700002102018700001902039700002402058700001902082700001702101700002402118700001902142700001702161856007202178 2020 eng d00aGeochemistry of aeolian material from the McMurdo Dry Valleys, Antarctica: Insights into Southern Hemisphere dust sources0 aGeochemistry of aeolian material from the McMurdo Dry Valleys An c10/20200 v5473 a

In the Southern Hemisphere, the major sources of dust and other aeolian materials are from Patagonia, South Africa, Australia, and New Zealand. Dust from Patagonia and New Zealand has been identified in ice cores throughout Antarctica, suggesting that during arid and windy periods, such as glacial periods, dust can be entrained and transported onto the continent. However, little information exists on modern Antarctic dust sources, transport, and its role in the Southern Hemisphere dust cycle. We present the first geochemical characterization of aeolian materials collected at five heights (between 5 cm and 100 cm) above the surface in four valleys within the McMurdo Dry Valleys, the largest ice-free area in Antarctica. Our mineralogy data indicate that these materials are primarily derived from local rocks of the McMurdo Volcanics, Ferrar Dolerite, Beacon Sandstone and Granite Harbor Intrusives, with varying contributions of each rock type dependent on the valley location. While major oxide, trace element and rare earth element data show that low elevation and coastal locations (with respect to the Ross Sea) are dominated by local sources, high elevation and inland locations have accumulated both local materials and dust from other distant Southern Hemisphere sources. This far-traveled material may not be accumulating today, but represents a paleo source that is resuspended from the soils. By geochemically “fingerprinting” aeolian materials from the MDV, we can better inform future studies on the transport of materials within Antarctica and between Southern Hemisphere land masses.

10aaeolian material10aAntarctica10amajor oxides10amineralogy10arare earth elements10atrace elements1 aDiaz, Melisa, A.1 aWelch, Susan, A.1 aSheets, J., M.1 aWelch, Kathleen, A.1 aKhan, Alia, L.1 aAdams, Byron1 aMcKnight, Diane, M.1 aCary, Craig, S1 aLyons, Berry uhttps://www.sciencedirect.com/science/article/pii/S0012821X2030404003683nas a2200997 4500008004100000245008200041210006900123260001200192490000600204520084100210100002601051700001901077700002001096700001401116700002501130700002501155700001701180700001701197700001901214700002601233700002301259700002701282700002301309700002101332700003101353700001801384700002101402700002001423700003001443700001501473700002001488700001901508700002501527700002301552700001901575700002101594700001701615700002201632700002101654700002601675700002301701700001101724700001701735700002201752700002101774700003101795700002401826700002201850700001501872700002201887700001801909700001701927700002501944700002201969700001901991700002702010700001602037700001802053700002202071700003202093700002302125700002302148700002002171700002202191700002002213700002702233700001802260700002102278700001902299700002302318700001502341700002302356700002202379700002402401700002102425700002302446700002102469700001802490700001802508700001902526700001402545700002802559700001702587700002702604856005402631 2020 eng d00aA global database of soil nematode abundance and functional group composition0 aglobal database of soil nematode abundance and functional group  c03/20200 v73 a

As the most abundant animals on earth, nematodes are a dominant component of the soil community. they play critical roles in regulating biogeochemical cycles and vegetation dynamics within and across landscapes and are an indicator of soil biological activity. Here, we present a comprehensive global dataset of soil nematode abundance and functional group composition. This dataset includes 6,825 georeferenced soil samples from all continents and biomes. For geospatial mapping purposes these samples are aggregated into 1,933 unique 1-km pixels, each of which is linked to 73 global environmental covariate data layers. Altogether, this dataset can help to gain insight into the spatial distribution patterns of soil nematode abundance and community composition, and the environmental drivers shaping these patterns.

1 avan den Hoogen, Johan1 aGeisen, Stefan1 aWall, Diana, H.1 aWardle, D1 aTraunspurger, Walter1 ade Goede, Ron, G. M.1 aAdams, Byron1 aAhmad, Wasim1 aFerris, Howard1 aBardgett, Richard, D.1 aBonkowski, Michael1 aCampos-Herrera, Raquel1 aCares, Juvenil, E.1 aCaruso, Tancredi1 aCaixeta, Larissa, de Brito1 aChen, Xiaoyun1 aCosta, Sofia, R.1 aCreamer, Rachel1 aCastro, José, da Cunha e1 aDam, Marie1 aDjigal, Djibril1 aEscuer, Miguel1 aGriffiths, Bryan, S.1 aGutiérrez, Carmen1 aHohberg, Karin1 aKalinkina, Daria1 aKardol, Paul1 aKergunteuil, Alan1 aKorthals, Gerard1 aKrashevska, Valentyna1 aKudrin, Alexey, A.1 aLi, Qi1 aLiang, Wenju1 aMagilton, Matthew1 aMarais, Mariette1 aMartín, José, Antonio Ro1 aMatveeva, Elizaveta1 aMayad, El, Hassan1 aMzough, E.1 aMulder, Christian1 aMullin, Peter1 aNeilson, Roy1 aNguyen, T., A. Duong1 aNielsen, Uffe, N.1 aOkada, Hiroaki1 aRius, Juan, Emilio Pal1 aPan, Kaiwen1 aPeneva, Vlada1 aPellissier, Loïc1 ada Silva, Julio, Carlos Per1 aPitteloud, Camille1 aPowers, Thomas, O.1 aPowers, Kirsten1 aQuist, Casper, W.1 aRasmann, Sergio1 aMoreno, Sara, Sánchez1 aScheu, Stefan1 aSetälä, Heikki1 aSushchuk, Anna1 aTiunov, Alexei, V.1 aTrap, Jean1 aVestergård, Mette1 aVillenave, Cecile1 aWaeyenberge, Lieven1 aWilschut, Rutger1 aWright, Daniel, G.1 aKeith, Aidan, M.1 aYang, Jiue-in1 aSchmidt, Olaf1 aBouharroud, R.1 aFerji, Z.1 avan der Putten, Wim, H.1 aRouth, Devin1 aCrowther, Thomas, Ward uhttps://www.nature.com/articles/s41597-020-0437-302448nas a2200217 4500008004100000245010000041210006900141260001200210490000700222520174400229100001201973700001901985700002702004700002102031700001602052700001702068700002902085700002302114700002102137856007202158 2020 eng d00aMethane production in the oxygenated water column of a perennially ice‐covered Antarctic lake0 aMethane production in the oxygenated water column of a perennial c01/20200 v653 a

Aerobic methane production in aquatic ecosystems impacts the global atmospheric budget of methane, but the extent, mechanism, and taxa responsible for producing this greenhouse gas are not fully understood. Lake Bonney (LB), a perennially ice‐covered Antarctic lake, has cold hypersaline waters underlying an oxygenated freshwater layer. We present temporal methane concentration profiles in LB indicating methane production in the oxygenated (> 200% air saturation) water. Experiments amended with methylphosphonate (MPn) yielded methane generation, suggesting in situ methanogenesis via the carbon‐phosphorus (C‐P) lyase pathway. Enrichment cultures from the lake were used to isolate five bacterial strains capable of generating methane when supplied with MPn as the sole P source. Based on 16S rRNA gene sequencing, the isolates belong to the Proteobacteria (closely related to Marinomonas, Hoeflea, and Marinobacter genera) and Bacteroidetes (Algoriphagus genus). 16S rRNA metagenomic sequencing confirms the presence of these taxa in LB. None of the isolated species were reported to be capable to produce methane. In addition, orthologs of the phosphoenolpyruvate mutase gene (PepM) and methylphosphonate synthase (MPnS), enzymes involved in phosphonate and MPn biosynthesis, were widely spread in the LB shotgun metagenomic libraries; genes related to C‐P lyase pathways (phn gene clusters) were also abundant. 16S rRNA and mcrA genes of anaerobic methanogens were absent in both 16S rRNA and metagenomics libraries. These data reveal that in situ aerobic biological methane production is likely a significant source of methane in LB.

1 aLi, Wei1 aDore, John, E.1 aSteigmeyer, August, J.1 aCho, Yong‐Joon1 aKim, Ok-Sun1 aLiu, Yongqin1 aMorgan-Kiss, Rachael, M.1 aSkidmore, Mark, L.1 aPriscu, John, C. uhttps://aslopubs.onlinelibrary.wiley.com/doi/full/10.1002/lno.1125702966nas a2200205 4500008004100000245011200041210006900153260001200222490000600234520228000240100002102520700002202541700002302563700002602586700002102612700001502633700002402648700001702672856007102689 2020 eng d00aSilicon isotopes reveal a non-glacial source of silicon to Crescent Stream, McMurdo Dry Valleys, Antarctica0 aSilicon isotopes reveal a nonglacial source of silicon to Cresce c06/20200 v83 a

In high latitude environments, silicon is supplied to river waters by both glacial and non-glacial chemical weathering. The signal of these two end-members is often obscured by biological uptake and/or groundwater input in the river catchment. McMurdo Dry Valleys streams in Antarctica have no deep groundwater input, no connectivity between streams and no surface vegetation cover, and thus provide a simplified system for us to constrain the supply of dissolved silicon (DSi) to rivers from chemical weathering in a glacial environment. Here we report dissolved Si concentrations, germanium/silicon ratios (Ge/Si) and silicon isotope compositions (δ30SiDSi) in Crescent Stream, McMurdo Dry Valleys for samples collected between December and February in the 2014−2015, 2015−2016, and 2016−2017 austral seasons. The δ30SiDSi compositions and DSi concentrations are higher than values reported in wet-based glacial meltwaters, and form a narrow cluster within the range of values reported for permafrost dominated Arctic Rivers. High δ30SiDSi compositions, ranging from +0.90‰ to +1.39‰, are attributed to (i) the precipitation of amorphous silica during freezing of waters in isolated pockets of the hyporheic zone in the winter and the release of Si from unfrozen pockets during meltwater-hyporheic zone exchange in the austral summer, and (ii) additional Si isotope fractionation via long-term Si uptake in clay minerals and seasonal Si uptake into diatoms superimposed on this winter-derived isotope signal. There is no relationship between δ30SiDSi compositions and DSi concentrations with seasonal and daily discharge, showing that stream waters contain DSi that is in equilibrium with the formation of secondary Si minerals in the hyporheic zone. We show that δ30SiDSi compositions can be used as tracers of silicate weathering in the hyporheic zone and possible tracers of freeze-thaw conditions in the hyporheic zone. This is important in the context of the ongoing warming in McMurdo Dry Valleys and the supply of more meltwaters to the hyporheic zone of McMurdo Dry Valley streams.

1 aHirst, Catherine1 aOpfergelt, Sophie1 aGaspard, François1 aHendry, Katharine, R.1 aHatton, Jade, E.1 aWelch, Sue1 aMcKnight, Diane, M.1 aLyons, Berry uhttps://www.frontiersin.org/articles/10.3389/feart.2020.00229/full02674nas a2200253 4500008004100000245007700041210006900118260001200187490000600199520187800205100002102083700002602104700002102130700002202151700001902173700002502192700002102217700002202238700001702260700002302277700002502300700002402325856007102349 2020 eng d00aSilicon isotopic composition of dry and wet-based glaciers in Antarctica0 aSilicon isotopic composition of dry and wetbased glaciers in Ant c07/20200 v83 a

Glaciers and ice sheets export significant amounts of silicon (Si) to downstream ecosystems, impacting local and potentially global biogeochemical cycles. Recent studies have shown Si in Arctic glacial meltwaters to have an isotopically distinct signature when compared to non-glacial rivers. This is likely linked to subglacial weathering processes and mechanochemical reactions. However, there are currently no silicon isotope (δ30Si) data available from meltwater streams in Antarctica, limiting the current inferences on global glacial silicon isotopic composition and its drivers. To address this gap, we present dissolved silicon (DSi), δ30SiDSi, and major ion data from meltwater streams draining a polythermal glacier in the region of the West Antarctic Peninsula (WAP; King George Island) and a cold-based glacier in East Antarctica [Commonwealth Stream, McMurdo Dry Valleys (MDV)]. These data, alongside other global datasets, improve our understanding of how contrasting glacier thermal regime can impact upon Si cycling and therefore the δ30SiDSi composition. We find a similar δ30SiDSi composition between the two sites, with the streams on King George Island varying between -0.23 and +1.23‰ and the Commonwealth stream varying from -0.40 to +1.14‰. However, meltwater streams in King George Island have higher DSi concentrations, and the two glacial systems exhibit opposite DSi – δ30SiDSi trends. These contrasts likely result from differences in weathering processes, specifically the role of subglacial processes (King George Island) and, supraglacial processes followed by in-stream weathering in hyporheic zones (Commonwealth Stream). These findings are important when considering likely changes in nutrient fluxes from Antarctic glaciers under climatic warming scenarios and consequent shifts in glacial thermal regimes.

1 aHatton, Jade, E.1 aHendry, Katharine, R.1 aHirst, Catherine1 aOpfergelt, Sophie1 aHenkel, Susann1 aSilva-Busso, Adrián1 aWelch, Susan, A.1 aWadham, Jemma, L.1 aLyons, Berry1 aBagshaw, Elizabeth1 aStaubwasser, Michael1 aMcKnight, Diane, M. uhttps://www.frontiersin.org/articles/10.3389/feart.2020.00286/full01789nas a2200205 4500008004100000245008500041210006900126260001200195520112400207653001601331653001801347653001001365653001501375653001601390100001901406700002101425700002201446700002101468856009401489 2020 eng d00aSubglacial brine flow and wind-induced internal waves in Lake Bonney, Antarctica0 aSubglacial brine flow and windinduced internal waves in Lake Bon c02/20203 a

Brine beneath Taylor Glacier has been proposed to enter the proglacial west lobe of Lake Bonney (WLB) as well as from Blood Falls, a surface discharge point at the Taylor Glacier terminus. The brine strongly influences the geochemistry of the water column of WLB. Year-round measurements from this study are the first to definitively identify brine intrusions from a subglacial entry point into WLB. Furthermore, we excluded input from Blood Falls by focusing on winter dynamics when the absence of an open water moat prevents surface brine entry. Due to the extremely high salinities below the chemocline in WLB, density stratification is dominated by salinity, and temperature can be used as a passive tracer. Cold brine intrusions enter WLB at the glacier face and intrude into the water column at the depth of neutral buoyancy, where they can be identified by anomalously cold temperatures at that depth. High-resolution measurements also reveal under-ice internal waves associated with katabatic wind events, a novel finding that challenges long-held assumptions about the stability of the WLB water column.

10aDry valleys10ahypersalinity10alakes10aproglacial10atemperature1 aLawrence, Jade1 aDoran, Peter, T.1 aWinslow, Luke, A.1 aPriscu, John, C. uhttps://www.cambridge.org/core/services/aop-cambridge-core/content/view/S095410202000003602684nas a2200265 4500008004100000022001400041245014900055210006900204260001200273490000600285520185300291653001502144653002502159653000902184653001802193653001702211100001502228700001802243700001602261700001202277700001402289700002102303700002902324856006502353 2019 eng d a0166-859500aThe Antarctic psychrophiles Chlamydomonas spp. UWO241 and ICE-MDV exhibit differential restructuring of photosystem I in response to iron0 aAntarctic psychrophiles iChlamydomonasi spp UWO241 and ICEMDV ex c02/20190 v93 a

Chlamydomonas sp. UWO241 is a psychrophilic alga isolated from the deep photic zone of a perennially ice-covered Antarctic lake (east lobe Lake Bonney, ELB). Past studies have shown that C. sp. UWO241 exhibits constitutive downregulation of photosystem I (PSI) and high rates of PSI-associated cyclic electron flow (CEF). Iron levels in ELB are in the nanomolar range leading us to hypothesize that the unusual PSI phenotype of C. sp. UWO241 could be a response to chronic Fe-deficiency. We studied the impact of Fe availability in C. sp. UWO241, a mesophile, C. reinhardtii SAG11-32c, as well as a psychrophile isolated from the shallow photic zone of ELB, Chlamydomonas sp. ICE-MDV. Under Fe-deficiency, PsaA abundance and levels of photooxidizable P700 (ΔA820/A820) were reduced in both psychrophiles relative to the mesophile. Upon increasing Fe, C. sp. ICE-MDV and C. reinhardtii exhibited restoration of PSI function, while C. sp. UWO241 exhibited only moderate changes in PSI activity and lacked almost all LHCI proteins. Relative to Fe-excess conditions (200 μM Fe2+), C. sp. UWO241 grown in 18 μM Fe2+ exhibited downregulation of light harvesting and photosystem core proteins, as well as upregulation of a bestrophin-like anion channel protein and two CEF-associated proteins (NdsS, PGL1). Key enzymes of starch synthesis and shikimate biosynthesis were also upregulated. We conclude that in response to variable Fe availability, the psychrophile C. sp. UWO241 exhibits physiological plasticity which includes restructuring of the photo-chemical apparatus, increased PSI-associated CEF, and shifts in downstream carbon metabolism toward storage carbon and secondary stress metabolites.

10aAntarctica10aCyclic electron flow10aIron10aPhotosystem I10aPsychrophile1 aCook, Greg1 aTeufel, Amber1 aKalra, Isha1 aLi, Wei1 aWang, Xin1 aPriscu, John, C.1 aMorgan-Kiss, Rachael, M. uhttps://link.springer.com/article/10.1007/s11120-019-00621-002353nas a2200397 4500008004100000245012200041210006900163260001200232490000600244520115100250100002101401700002501422700002101447700002101468700001401489700002201503700001701525700002201542700001701564700002001581700002001601700002401621700002201645700001901667700002401686700002401710700001701734700002301751700002001774700001801794700002401812700002201836700002401858700001901882856005401901 2019 eng d00aBiotic interactions are an unexpected yet critical control on the complexity of an abiotically driven polar ecosystem0 aBiotic interactions are an unexpected yet critical control on th c02/20190 v23 a

Abiotic and biotic factors control ecosystem biodiversity, but their relative contributions remain unclear. The ultraoligotrophic ecosystem of the Antarctic Dry Valleys, a simple yet highly heterogeneous ecosystem, is a natural laboratory well-suited for resolving the abiotic and biotic controls of community structure. We undertook a multidisciplinary investigation to capture ecologically relevant biotic and abiotic attributes of more than 500 sites in the Dry Valleys, encompassing observed landscape heterogeneities across more than 200 km2. Using richness of autotrophic and heterotrophic taxa as a proxy for functional complexity, we linked measured variables in a parsimonious yet comprehensive structural equation model that explained significant variations in biological complexity and identified landscape-scale and fine-scale abiotic factors as the primary drivers of diversity. However, the inclusion of linkages among functional groups was essential for constructing the best-fitting model. Our findings support the notion that biotic interactions make crucial contributions even in an extremely simple ecosystem.

1 aLee, Charles, K.1 aLaughlin, Daniel, C.1 aBottos, Eric, M.1 aCaruso, Tancredi1 aJoy, Kurt1 aBarrett, John, E.1 aBrabyn, Lars1 aNielsen, Uffe, N.1 aAdams, Byron1 aWall, Diana, H.1 aHopkins, D., W.1 aPointing, Steve, B.1 aMcDonald, Ian, R.1 aCowan, Don, A.1 aBanks, Jonathan, C.1 aStichbury, Glen, A.1 aJones, Irfon1 aZawar-Reza, Peyman1 aKaturji, Marwan1 aHogg, Ian, D.1 aSparrow, Ashley, D.1 aStorey, Bryan, C.1 aGreen, T., G. Allan1 aCary, Craig, S uhttps://www.nature.com/articles/s42003-018-0274-502939nas a2200241 4500008004100000245010800041210006900149260001200218300001100230490000800241520220100249653000902450653001602459653003202475653001302507653001302520100001602533700001802549700001402567700001502581700002902596856007202625 2019 eng d00aCommunity response of microbial primary producers to salinity is primarily driven by nutrients in lakes0 aCommunity response of microbial primary producers to salinity is c12/2019 a1340010 v6963 a

Higher microbial diversity was frequently observed in saline than fresh waters, but the underlying mechanisms remains unknown, particularly in microbial primary producers (MPP). MPP abundance and activity are notably constrained by high salinity, but facilitated by high nutrients. It remains to be ascertained whether and how nutrients regulate the salinity constraints on MPP abundance and community structure. Here we investigated the impact of nutrients on salinity constraints on MPP abundance and diversity in undisturbed lakes with a wide salinity range on the Tibetan Plateau. MPP community was explored using quantitative PCR, terminal restriction fragment length polymorphism and sequencing of cloning libraries targeting form IC cbbL gene. The MPP community structure was sorted by salinity into freshwater (salinity<1‰), saline (1‰ < salinity<29‰) and hypersaline (salinity>29‰) lakes. Furthermore, while MPP abundance, diversity and richness were significantly constrained with increasing salinity, these constraints were mitigated by enhancing total organic carbon (TOC) and total nitrogen (TN) contents in freshwater and saline lakes. In contrast, the MPP diversity increased significantly with the salinity in hypersaline lakes, due to the mitigation of enhancing TOC and TN contents and salt-tolerant MPP taxa. The mitigating effect of nutrients was more pronounced in saline than in freshwater and hypersaline lakes. The MPP compositions varied along salinity, with Betaproteobacteria dominating both the freshwater and saline lakes and Gammaproteobacteria dominating the hypersaline lakes. We concluded that high nutrients could mitigate the salinity constraining effects on MPP abundance, community richness and diversity. Our findings offer a novel insight into the salinity effects on primary producers and highlight the interactive effects of salinity and nutrients on MPP in lakes. These findings can be used as a baseline to illuminate the effects of increased anthropogenic activities altering nutrient dynamics on the global hydrological cycle and the subsequent responses thereof by MPP communities.

10acbbL10alake waters10amicrobial primary producers10anutrient10asalinity1 aYue, Linyan1 aKong, Weidong1 aJi, Mukan1 aLiu, Jinbo1 aMorgan-Kiss, Rachael, M. uhttps://www.sciencedirect.com/science/article/pii/S004896971933978601931nas a2200229 4500008004100000245010800041210006900149260001200218490000700230520115400237100002101391700001701412700001701429700002401446700002401470700001601494700001601510700001701526700001501543700002301558856012001581 2019 eng d00aDiurnal chemistry of two contrasting stream types, Taylor Valley, McMurdo Dry Valley Region, Antarctica0 aDiurnal chemistry of two contrasting stream types Taylor Valley  c06/20190 v983 a

Numerous ephemeral streams flow within the McMurdo Dry Valley Region of Antarctica that transport glacial meltwater to perennially ice-covered, closed-basin lakes during the austral summer. The diurnal behavior for two Taylor Valley streams of different character was examined during the summer of 2010-11. Andersen Creek is a short, 1st-order proglacial stream, whereas Von Guerard Stream is a long, high-order stream with an extensive hyporheic zone that has a substantial cyanobacterial algal mat community in its middle reaches. Both streams display strong daily cycles for temperature, electrical conductivity, dissolved oxygen, and pH. Conductivity varies in concert with flow, with solute dilution occurring during the daily high-flow pulse. Dissolved oxygen co-varies strongly with pH at Andersen Creek but not for Von Guerard Stream. Each stream has a distinct geochemical character that for Andersen Creek is a direct reflection of its glacial source, unmodified by secondary effects, whereas that for Von Guerard Stream is modulated by its resident algal mat community and through extensive hyporheic zone interaction and exchange.

1 aHarmon, Mark, E.1 aLeslie, D.L.1 aLyons, Berry1 aWelch, Kathleen, A.1 aMcKnight, Diane, M.1 aChudaev, O.1 aKharaka, Y.1 aHarmon, R.S.1 aMillot, R.1 aShouakar-Stash, O. uhttps://www.e3s-conferences.org/articles/e3sconf/abs/2019/24/e3sconf_wri-162018_01020/e3sconf_wri-162018_01020.html02573nas a2200265 4500008004100000022001400041245010400055210006900159260001200228300001400240490000700254520177600261653002002037653002102057653001502078653001702093653002402110653001202134653002502146100001202171700002002183700001602203700002902219856005902248 2019 eng d a0948-305500aDrivers of protistan community autotrophy and heterotrophy in chemically stratified Antarctic lakes0 aDrivers of protistan community autotrophy and heterotrophy in ch c01/2019 a225 - 2390 v823 a

Single-celled, eukaryotic microorganisms, known as protists, are responsible for 2 important, yet opposing, metabolic activities within aquatic food webs. They are major primary producers and highly active predators in marine and fresh water systems. While genomics has accelerated in recent years for this taxonomically diverse group, our understanding of the metabolic capabilities of most protists remains limited. It is also poorly understood how protist trophic mode is affected by biotic and abiotic factors, and therefore it is difficult to predict how events such as global climate change will affect the balance between autotrophic and heterotrophic activities in protist communities. To address open questions regarding how protist metabolic versatility is influenced by their environment, we characterized the potential for carbon fixation versus organic carbon degradation using enzymatic assays (RubisCO and β-D-glucosaminidase, respectively) within the water columns of ice-covered lakes in McMurdo Dry Valleys (MDV), Antarctica. Steep physical and chemical gradients in the water columns, microorganism domination and minimal allochthonous inputs makes the MDV lakes uniquely suited to investigate environment-microbe interactions. Spatial trends in RubisCO and β-D-glucosaminidase activities were lake-specific and vertically stratified within the water columns. Moreover, bottom-up drivers controlling the activity of C-fixation vs. organic C-degradation among the MDV protist communities were distinct between the upper photic vs. the deep, aphotic zones. We conclude that differential controls over major C-cycling enzymes have important implications on the influence of environmental change on the carbon and nutrient cycles in the MDV lakes.

10aAntarctic lakes10aAquatic protists10aAutotrophy10aHeterotrophy10aMcMurdo Dry Valleys10aRubisCO10aβ-D-glucosaminidase1 aLi, Wei1 aDolhi-Binder, J1 aCariani, ZE1 aMorgan-Kiss, Rachael, M. uhttps://www.int-res.com/abstracts/ame/v82/n3/p225-239/02504nas a2200229 4500008004100000245007200041210006700113260001200180490000800192520178600200100001701986700002202003700002202025700002402047700001502071700002902086700002502115700002102140700002002161700002002181856007302201 2019 eng d00aThe Geochemistry of Englacial Brine From Taylor Glacier, Antarctica0 aGeochemistry of Englacial Brine From Taylor Glacier Antarctica c03/20190 v1243 a

Blood Falls is a hypersaline, iron‐rich discharge at the terminus of the Taylor Glacier in the McMurdo Dry Valleys, Antarctica. In November 2014, brine in a conduit within the glacier was penetrated and sampled using clean‐entry techniques and a thermoelectric melting probe called the IceMole. We analyzed the englacial brine sample for filterable iron (fFe), total Fe, major cations and anions, nutrients, organic carbon, and perchlorate. In addition, aliquots were analyzed for minor and trace elements and isotopes including δD and δ18O of water, δ34S and δ18O of sulfate, 234U, 238U, δ11B, 87Sr/86Sr, and δ81Br. These measurements were made in order to (1) determine the source and geochemical evolution of the brine and (2) compare the chemistry of the brine to that of nearby hypersaline lake waters and previous supraglacially sampled collections of Blood Falls outflow that were interpreted as end‐member brines. The englacial brine had higher Cl− concentrations than the Blood Falls end‐member outflow; however, other constituents were similar. The isotope data indicate that the water in the brine is derived from glacier melt. The H4SiO4 concentrations and U and Sr isotope suggest a high degree of chemical weathering products. The brine has a low N:P ratio of ~7.2 with most of the dissolved inorganic nitrogen in the form of NH4+. Dissolved organic carbon concentrations are similar to end‐member outflow values. Our results provide strong evidence that the original source of solutes in the brine was ancient seawater, which has been modified with the addition of chemical weathering products.

1 aLyons, Berry1 aMikucki, Jill, A.1 aGerman, Laura, A.1 aWelch, Kathleen, A.1 aWelch, Sue1 aGardner, Christopher, B.1 aTulaczyk, Slawek, M.1 aPettit, Erin, C.1 aKowalski, Julia1 aDachwald, Bernd uhttps://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JG00441102216nas a2200193 4500008004100000245012200041210006900163260001200232520155300244653001501797653001701812653002101829653002901850653001801879100002101897700001501918700001701933856007201950 2019 eng d00aThe geochemistry of glacial deposits in Taylor Valley, Antarctica: Comparison to upper continental crustal abundances0 ageochemistry of glacial deposits in Taylor Valley Antarctica Com c05/20193 a

Wet-based glacial deposits have been used traditionally as an analog for upper continental crust (UCC) abundances. To provide more information on the validity of using glacial deposits from wet-based glaciers, samples deposited by the dry-based polar glaciers located in Taylor Valley, Antarctica, were collected. Stream channel sediments, comprised of igneous, metamorphic, and sedimentary rocks initially deposited as glacial tills by polar glaciers, were analyzed by XRF, ICP-MS, and SEM. Based on the Chemical Index of Alteration values and A–CN–K ternary diagram, there are low levels of chemical weathering in these tills. Additionally, major and trace element geochemical data are compared to the average UCC values. The observed discrepancies between the mean UCC and Antarctic samples develop from the existence of mafic components, most likely the McMurdo Volcanic Group and Ferrar Dolerite, being present in the Taylor Valley tills. Even though the mafic material typically comprises 3–7% of the till, the volcanic rocks have a significant influence on the tills’ bulk geochemistry. The existence of this mafic fraction in the dry-based glacial tills results from the reduced rate of weathering, as compared to wet-based glaciers. Geochemical analyses of the dry-based glacial tills in polar deserts, such as those found in Taylor Valley, may provide a better representative composition of the original material than wet-based glaciers and need to be incorporated into upper continental crust calculations.

10aAntarctica10ageochemistry10aglacial deposits10apolar dry-based glaciers10aTaylor Valley1 aDowling, Carolyn1 aWelch, Sue1 aLyons, Berry uhttps://www.sciencedirect.com/science/article/pii/S088329271930124602639nas a2200301 4500008004100000245008400041210006900125260001200194520169800206653001501904653002101919653002401940653002701964653001301991100002102004700002602025700001702051700001602068700002502084700002502109700001702134700002202151700002302173700002002196700002402216700002402240856007302264 2019 eng d00aThe hydroecology of an ephemeral wetland in the McMurdo Dry Valleys, Antarctica0 ahydroecology of an ephemeral wetland in the McMurdo Dry Valleys  c11/20193 a

The McMurdo Dry Valleys (MDV) is a polar desert on the coast of East Antarctica where ephemeral wetlands become hydrologically active during warm and sunny summers when sub‐surface flows are generated from melting snowfields. To understand the structure and function of polar wetland ecosystems, we investigated the hydroecology of one such wetland, the Wormherder Creek wetland, during the warm and sunny summer of 2008 – 2009, when the wetland was hydrologically reactivated. Conservative tracer (LiCl) was injected for a 2‐hour period into a stream above the wetland to determine flow path orientations and hydrologic residence times. Tracer results indicated that surface water is rapidly exchanged with wetland groundwater and wetland residence times may exceed two austral summers. Major ion concentrations were uniform in samples from surface water and shallow groundwater throughout the wetland. Microbial mats in the wetland had high autotrophic index values (the ratios of chlorophyll a [Chl‐a]/ash‐free dry mass [AFDM]), ranging from 9‐38 μg Chl‐a/mg AFDM, indicative of actively photosynthesizing mat communities. The diatom communities in the mats were relatively uniform compared to those in mats from regularly flowing MDV streams, with four endemic and one widespread diatom taxa of the genus Luticola accounting for an average of 86% of the community. These results indicate that the hydrologic characteristics of the wetland contribute to uniform geochemical conditions. In turn, uniform geochemical conditions may explain the high autotrophic index values of the microbial mats and relatively low spatial variation of the diatom community.

10aAntarctica10adesert hydrology10adiatom biodiversity10ahyporheic interactions10awetlands1 aWlostowski, Adam1 aSchulte, Nicholas, O.1 aAdams, Byron1 aBall, Becky1 aEsposito, Rhea, M.M.1 aGooseff, Michael, N.1 aLyons, Berry1 aNielsen, Uffe, N.1 aVirginia, Ross, A.1 aWall, Diana, H.1 aWelch, Kathleen, A.1 aMcKnight, Diane, M. uhttps://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JG00515302372nas a2200193 4500008004100000245016100041210006900202260001200271490000700283520165600290653002101946653002601967653002701993653001702020653002902037100001202066700002902078856007102107 2019 eng d00aInfluence of environmental drivers and potential interactions on the distribution of microbial communities from three permanently stratified Antarctic lakes0 aInfluence of environmental drivers and potential interactions on c05/20190 v103 a

The McMurdo Dry Valley (MDV) lakes represent unique habitats in the microbial world. Perennial ice covers protect liquid water columns from either significant allochthonous inputs or seasonal mixing, resulting in centuries of stable biogeochemistry. Extreme environmental conditions including low seasonal photosynthetically active radiation (PAR), near freezing temperatures, and oligotrophy have precluded higher trophic levels from the food webs. Despite these limitations, diverse microbial life flourishes in the stratified water columns, including Archaea, bacteria, fungi, protists, and viruses. While a few recent studies have applied next generation sequencing, a thorough understanding of the MDV lake microbial diversity and community structure is currently lacking. Here we used Illumina MiSeq sequencing of the 16S and 18S rRNA genes combined with a microscopic survey of key eukaryotes to compare the community structure and potential interactions among the bacterial and eukaryal communities within the water columns of Lakes Bonney (east and west lobes, ELB, and WLB, respectively) and Fryxell (FRX). Communities were distinct between the upper, oxic layers and the dark, anoxic waters, particularly among the bacterial communities residing in WLB and FRX. Both eukaryal and bacterial community structure was influenced by different biogeochemical parameters in the oxic and anoxic zones. Bacteria formed complex interaction networks which were lake-specific. Several eukaryotes exhibit potential interactions with bacteria in ELB and WLB, while interactions between these groups in the more productive FRX were relatively rare.

10aAquatic protists10aenvironmental drivers10aheterotrophic bacteria10ainteractions10aMcMurdo Dry Valley lakes1 aLi, Wei1 aMorgan-Kiss, Rachael, M. uhttps://www.frontiersin.org/articles/10.3389/fmicb.2019.01067/full01860nas a2200253 4500008004100000245011500041210006900156260001200225490000600237520106300243100002101306700001801327700002201345700002101367700002101388700002001409700001901429700002201448700002401470700002201494700002001516700001701536856005301553 2019 eng d00aNematodes in a polar desert reveal the relative role of biotic interactions in the coexistence of soil animals0 aNematodes in a polar desert reveal the relative role of biotic i c02/20190 v23 a

Abiotic factors are major determinants of soil animal distributions and their dominant role is pronounced in extreme ecosystems, with biotic interactions seemingly playing a minor role. We modelled co-occurrence and distribution of the three nematode species that dominate the soil food web of the McMurdo Dry Valleys (Antarctica). Abiotic factors, other biotic groups, and autocorrelation all contributed to structuring nematode species distributions. However, after removing their effects, we found that the presence of the most abundant nematode species greatly, and negatively, affected the probability of detecting one of the other two species. We observed similar patterns in relative abundances for two out of three pairs of species. Harsh abiotic conditions alone are insufficient to explain contemporary nematode distributions whereas the role of negative biotic interactions has been largely underestimated in soil. The future challenge is to understand how the effects of global change on biotic interactions will alter species coexistence.

1 aCaruso, Tancredi1 aHogg, Ian, D.1 aNielsen, Uffe, N.1 aBottos, Eric, M.1 aLee, Charles, K.1 aHopkins, D., W.1 aCary, Craig, S1 aBarrett, John, E.1 aGreen, T., G. Allan1 aStorey, Bryan, C.1 aWall, Diana, H.1 aAdams, Byron uhttp://www.nature.com/articles/s42003-018-0260-y01888nas a2200301 4500008004100000245004500041210004100086260001200127300001300139490000600152520103800158100001501196700002301211700002801234700002401262700002201286700002501308700001401333700002301347700002401370700002201394700002001416700002601436700001601462700002301478700001601501856006901517 2019 eng d00aThe polar regions in a 2°C warmer world0 apolar regions in a 2°C warmer world c12/2019 aeaaw98830 v53 a

Over the past decade, the Arctic has warmed by 0.75°C, far outpacing the global average, while Antarctic tem- peratures have remained comparatively stable. As Earth approaches 2°C warming, the Arctic and Antarctic may reach 4°C and 2°C mean annual warming, and 7°C and 3°C winter warming, respectively. Expected consequences of increased Arctic warming include ongoing loss of land and sea ice, threats to wildlife and traditional human livelihoods, increased methane emissions, and extreme weather at lower latitudes. With low biodiversity, Antarctic ecosystems may be vulnerable to state shifts and species invasions. Land ice loss in both regions will contribute substantially to global sea level rise, with up to 3 m rise possible if certain thresholds are crossed. Mitigation efforts can slow or reduce warming, but without them northern high latitude warming may accelerate in the next two to four decades. International cooperation will be crucial to foreseeing and adapting to expected changes.

1 aPost, Eric1 aAlley, Richard, B.1 aChristensen, Torben, R.1 aMacias-Fauria, Marc1 aForbes, Bruce, C.1 aGooseff, Michael, N.1 aIler, Amy1 aKerby, Jeffrey, T.1 aLaidre, Kristin, L.1 aMann, Michael, E.1 aOlofsson, Johan1 aStroeve, Julienne, C.1 aUlmer, Fran1 aVirginia, Ross, A.1 aWang, Muyin uhttp://advances.sciencemag.org/lookup/doi/10.1126/sciadv.aaw988303892nas a2200949 4500008004100000245007900041210006900120260001200189490000800201520116600209100002601375700001901401700001701420700001901437700002501456700001401481700002501495700001701520700001701537700002601554700002601580700002301606700002701629700002301656700002101679700003101700700001801731700002101749700002001770700003001790700001501820700002001835700001901855700002501874700002301899700001901922700002101941700001701962700002201979700002102001700002602022700002302048700001102071700001702082700002202099700002102121700003102142700002402173700002202197700002202219700001802241700001702259700002502276700002202301700001902323700002702342700001602369700001802385700002202403700003202425700002302457700002302480700002002503700002202523700002002545700002702565700001802592700002102610700001902631700002302650700001502673700002202688700002302710700002202733700002402755700002002779700002102799700002302820700001802843700002702861856005402888 2019 eng d00aSoil nematode abundance and functional group composition at a global scale0 aSoil nematode abundance and functional group composition at a gl c08/20190 v5723 a

Soil organisms are a crucial part of the terrestrial biosphere. Despite their importance for ecosystem functioning, few quantitative, spatially explicit models of the active belowground community currently exist. In particular, nematodes are the most abundant animals on Earth, filling all trophic levels in the soil food web. Here we use 6,759 georeferenced samples to generate a mechanistic understanding of the patterns of the global abundance of nematodes in the soil and the composition of their functional groups. The resulting maps show that 4.4 ± 0.64 × 1020 nematodes (with a total biomass of approximately 0.3 gigatonnes) inhabit surface soils across the world, with higher abundances in sub-Arctic regions (38% of total) than in temperate (24%) or tropical (21%) regions. Regional variations in these global trends also provide insights into local patterns of soil fertility and functioning. These high-resolution models provide the first steps towards representing soil ecological processes in global biogeochemical models and will enable the prediction of elemental cycling under current and future climate scenarios.

1 avan den Hoogen, Johan1 aGeisen, Stefan1 aRouth, Devin1 aFerris, Howard1 aTraunspurger, Walter1 aWardle, D1 ade Goede, Ron, G. M.1 aAdams, Byron1 aAhmad, Wasim1 aAndriuzzi, Walter, S.1 aBardgett, Richard, D.1 aBonkowski, Michael1 aCampos-Herrera, Raquel1 aCares, Juvenil, E.1 aCaruso, Tancredi1 aCaixeta, Larissa, de Brito1 aChen, Xiaoyun1 aCosta, Sofia, R.1 aCreamer, Rachel1 aCastro, José, Mauro da C1 aDam, Marie1 aDjigal, Djibril1 aEscuer, Miguel1 aGriffiths, Bryan, S.1 aGutiérrez, Carmen1 aHohberg, Karin1 aKalinkina, Daria1 aKardol, Paul1 aKergunteuil, Alan1 aKorthals, Gerard1 aKrashevska, Valentyna1 aKudrin, Alexey, A.1 aLi, Qi1 aLiang, Wenju1 aMagilton, Matthew1 aMarais, Mariette1 aMartín, José, Antonio Ro1 aMatveeva, Elizaveta1 aMayad, El, Hassan1 aMulder, Christian1 aMullin, Peter1 aNeilson, Roy1 aNguyen, T., A. Duong1 aNielsen, Uffe, N.1 aOkada, Hiroaki1 aRius, Juan, Emilio Pal1 aPan, Kaiwen1 aPeneva, Vlada1 aPellissier, Loïc1 ada Silva, Julio, Carlos Per1 aPitteloud, Camille1 aPowers, Thomas, O.1 aPowers, Kirsten1 aQuist, Casper, W.1 aRasmann, Sergio1 aMoreno, Sara, Sánchez1 aScheu, Stefan1 aSetälä, Heikki1 aSushchuk, Anna1 aTiunov, Alexei, V.1 aTrap, Jean1 avan der Putten, W1 aVestergård, Mette1 aVillenave, Cecile1 aWaeyenberge, Lieven1 aWall, Diana, H.1 aWilschut, Rutger1 aWright, Daniel, G.1 aYang, Jiue-in1 aCrowther, Thomas, Ward uhttps://www.nature.com/articles/s41586-019-1418-602534nas a2200229 4500008004100000245010900041210006900150260001200219300001600231490000800247520179600255100002102051700001702072700002402089700001502113700002302128700001902151700002402170700001902194700001702213856007402230 2018 eng d00aAeolian material transport and its role in landscape connectivity in the McMurdo Dry Valleys, Antarctica0 aAeolian material transport and its role in landscape connectivit c12/2018 a3323 - 33370 v1233 a

Arid regions, particularly polar and alpine desert environments, have diminished landscape connectivity compared to temperate regions due to limited and/or seasonal hydrological processes. For these environments, aeolian processes play a particularly important role in landscape evolution and biotic community vitality through nutrient and solute additions. The McMurdo Dry Valleys (MDV) are the largest ice-free area in Antarctica and are potentially a major source of aeolian material for the continent. From this region, samples were collected at five heights (~5, 10, 20, 50, and 100 cm) above the surface seasonally for 2013 through 2015 from Alatna Valley, Victoria Valley, Miers Valley, and Taylor Valley (Taylor Glacier, East Lake Bonney, F6 (Lake Fryxell), and Explorer’s Cove). Despite significant geological separation and varying glacial histories, low-elevation and coastal sites had similar major ion chemistries, as did high-elevation and inland locations. This locational clustering of compositions was also evident in scanning electron microscopy images and principal component analyses, particularly for samples collected at ~100 cm above the surface. Compared to published soil literature, aeolian material in Taylor Valley demonstrates a primarily down-valley transport of material toward the coast. Soluble N:P ratios in the aeolian material reflect relative nutrient enrichments seen in MDV soils and lakes, where younger, coastal soils are relatively N depleted, while older, up-valley soils are relatively P depleted. The aeolian transport of materials, including water-soluble nutrients, is an important vector of connectivity within the MDV and provides a mechanism to help “homogenize” the geochemistry of both soil and aquatic ecosystems.

1 aDiaz, Melisa, A.1 aAdams, Byron1 aWelch, Kathleen, A.1 aWelch, Sue1 aOpiyo, Stephen, O.1 aKhan, Alia, L.1 aMcKnight, Diane, M.1 aCary, Craig, S1 aLyons, Berry uhttps://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2017JF00458901847nas a2200193 4500008004100000022001400041245005200055210005200107260001200159300001400171490000700185520124200192100002201434700002901456700002401485700001501509700001701524856011201541 2018 eng d a0091-761300aBarium and barite dynamics in Antarctic streams0 aBarium and barite dynamics in Antarctic streams c08/2018 a811 - 8140 v463 a

Most natural waters are undersaturated with respect to barite (BaSO4), and while much work has focused on the processes of microbially mediated barite precipitation in undersaturated solutions, particularly in marine environments, little documentation exists on the changes in barite saturation in stream waters. We examined ephemeral glacial meltwater streams in the McMurdo Dry Valleys, Antarctica, that undergo large variations in streamflow and temperature on both a diel and seasonal basis. We measured dissolved Ba in stream water in downstream transects and on a diel cycle, total Ba in stream sediments, algal mats, and lake sediments. Ba concentrations decreased downstream in all four transects, and mineral saturation modeling indicates these waters go from supersaturated to undersaturated with respect to barite in very short distances. Ba is concentrated in stream benthic algal mats at a factor less than observed in marine systems. Both seasonal and diel changes in stream water temperature affect the solubility of barite near glacial sources. Our work shows that both changing stream temperature and the presence of algal materials likely play significant roles in controlling Ba concentrations in polar streams.

1 aSaelens, Elsa, D.1 aGardner, Christopher, B.1 aWelch, Kathleen, A.1 aWelch, Sue1 aLyons, Berry uhttps://pubs.geoscienceworld.org/gsa/geology/article/545184/Barium-and-barite-dynamics-in-Antarctic-streams02347nas a2200193 4500008004100000022001300041245009200054210006900146260001200215300001200227490000800239520173400247100002101981700001702002700001502019700002402034700002302058856007202081 2018 eng d a0016706100aBiogeochemical weathering of soil apatite grains in the McMurdo Dry Valleys, Antarctica0 aBiogeochemical weathering of soil apatite grains in the McMurdo  c01/2018 a136-1450 v3203 a

The biogeochemical weathering of the mineral apatite links the lithosphere to the biosphere by releasing the essential nutrient phosphorus (P) into the soil ecosystem. In Taylor Valley, Antarctica, faster rates of apatite weathering may be responsible for the higher concentrations of bioavailable soil P that exist in the Fryxell Basin as compared to the Bonney Basin. In this study, we use scanning electron microscopy to quantify the morphology and surface etching of individual apatite grains to determine whether the degree of apatite weathering differs between the Fryxell and Bonney Basins as well as saturated and dry soil sediments. We show that apatite grains from the Fryxell Basin are rounder, have fewer intact crystal faces, and are more chemically etched than grains from the Bonney Basin. In the Bonney Basin, apatite grains from dry soils show few signs of chemical dissolution, suggesting that soil moisture is a stronger control on the rate of apatite weathering in the Bonney Basin than in the Fryxell Basin. In addition, etch-pit morphologies in the Bonney Basin are more clearly controlled by the hexagonal crystal structure of apatite, while in the Fryxell Basin, etch pits demonstrate a wide range of morphologies without clear crystallographic control. Higher rates of apatite weathering in the Fryxell Basin may be due to the legacy of the physical abrasion of apatite grains during transport by a warm-based ice sheet, as well as the higher levels of precipitation and soil moisture closer to the coast. Our grain-scale approach provides a new perspective on P cycling in the McMurdo Dry Valleys and has implications for apatite weathering and P dynamics in the early stages of soil development.

1 aHeindel, Ruth, C1 aLyons, Berry1 aWelch, Sue1 aSpickard, Angela, M1 aVirginia, Ross, A. uhttps://www.sciencedirect.com/science/article/pii/S001670611732069410050nas a2202965 4500008004100000245007300041210006900114260001200183300001200195490000700207520154900214653001701763653001101780653001201791653002101803653001301824653001301837100002001850700002201870700001601892700002201908700002301930700001701953700002801970700002001998700002502018700001802043700002402061700001602085700002202101700002002123700002702143700002002170700002202190700002302212700003102235700002002266700002302286700002702309700002202336700002702358700002702385700001602412700001902428700002302447700002102470700002202491700001802513700002302531700002802554700002502582700002302607700002002630700002902650700002502679700002002704700002602724700002602750700001702776700002402793700002502817700002302842700002202865700001902887700002002906700002102926700002202947700002102969700001802990700001703008700002203025700001703047700002503064700001903089700002603108700002203134700001903156700002103175700001903196700002703215700003003242700002403272700002403296700001703320700002303337700003203360700002103392700002403413700002203437700002903459700001403488700003103502700002303533700001903556700002303575700002603598700001803624700002103642700001603663700001803679700002403697700002103721700002003742700001903762700001703781700001903798700002103817700002003838700002603858700002003884700002003904700002003924700002503944700002003969700002703989700002404016700003304040700001804073700001504091700002304106700002204129700002004151700001704171700002404188700001804212700002404230700002104254700002204275700002104297700002004318700002004338700002804358700002604386700001704412700002104429700001904450700002304469700003104492700002604523700002004549700002704569700002204596700002104618700002204639700002004661700002804681700001804709700002204727700002604749700002004775700001904795700002404814700001804838700002404856700002604880700001804906700002304924700002504947700002804972700002205000700002505022700001505047700001705062700001505079700003105094700001905125700001805144700002605162700002405188700001905212700001805231700002205249700002605271700002405297700002005321700002405341700002105365700002905386700002105415700002205436700002005458700001905478700002405497700002505521700002105546700002805567700001905595700002205614700001505636700002605651700002105677700002105698700002505719700002205744700001905766700002805785700002305813700002605836700002105862700002105883700002705904700002805931700002105959700001905980700001905999700003006018700002106048700002406069700003206093700003606125700001806161700001606179700002206195700002306217700001906240700001806259700001506277700002106292700002606313700003306339700001706372700002006389700002106409700002406430700002106454700002206475700001906497700002306516700002106539700001806560700002806578700003406606700002406640700002106664700001806685700002006703700003206723700002606755700002706781700002906808700003106837700002106868700002306889700002506912700002106937700002306958700002506981700001607006856006207022 2018 eng d00aBioTIME: A database of biodiversity time series for the Anthropocene0 aBioTIME A database of biodiversity time series for the Anthropoc c07/2018 a760-7860 v273 a

Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time series. Our goal is to accelerate and facilitate quantitative analysis of temporal patterns of biodiversity in the Anthropocene.

Main types of variables included: The database contains 8,777,413 species abundance records, from assemblages consistently sampled for a minimum of 2 years, which need not necessarily be consecutive. In addition, the database contains metadata relating to sampling methodology and contextual information about each record.

Spatial location and grain: BioTIME is a global database of 547,161 unique sampling locations spanning the marine, freshwater and terrestrial realms. Grain size varies across datasets from 0.0000000158 km2 (158 cm2) to 100 km2 (1,000,000,000,000 cm2). Time period and grain BioTIME records span from 1874 to 2016. The minimal temporal grain across all datasets in BioTIME is a year.

Major taxa and level of measurement: BioTIME includes data from 44,440 species across the plant and animal kingdoms, ranging from plants, plankton and terrestrial invertebrates to small and large vertebrates.

Software format: .csv and .SQL.

10abiodiversity10aglobal10aspatial10aspecies richness10atemporal10aturnover1 aDornelas, Maria1 aAntão, Laura, H.1 aMoyes, Faye1 aBates, Amanda, E.1 aMagurran, Anne, E.1 aAdam, Dušan1 aAkhmetzhanova, Asem, A.1 aAppeltans, Ward1 aArcos, José, Manuel1 aArnold, Haley1 aAyyappan, Narayanan1 aBadihi, Gal1 aBaird, Andrew, H.1 aBarbosa, Miguel1 aBarreto, Tiago, Egydio1 aBässler, Claus1 aBellgrove, Alecia1 aBelmaker, Jonathan1 aBenedetti-Cecchi, Lisandro1 aBett, Brian, J.1 aBjorkman, Anne, D.1 aBłażewicz, Magdalena1 aBlowes, Shane, A.1 aBloch, Christopher, P.1 aBonebrake, Timothy, C.1 aBoyd, Susan1 aBradford, Matt1 aBrooks, Andrew, J.1 aBrown, James, H.1 aBruelheide, Helge1 aBudy, Phaedra1 aCarvalho, Fernando1 aCastañeda-Moya, Edward1 aChen, Chaolun, Allen1 aChamblee, John, F.1 aChase, Tory, J.1 aCollier, Laura, Siegwart1 aCollinge, Sharon, K.1 aCondit, Richard1 aCooper, Elisabeth, J.1 aCornelissen, Hans, C.1 aCotano, Unai1 aCrow, Shannan, Kyle1 aDamasceno, Gabriella1 aDavies, Claire, H.1 aDavis, Robert, A.1 aDay, Frank, P.1 aDegraer, Steven1 aDoherty, Tim, S.1 aDunn, Timothy, E.1 aDurigan, Giselda1 aDuffy, Emmett1 aEdelist, Dor1 aEdgar, Graham, J.1 aElahi, Robin1 aElmendorf, Sarah, C.1 aEnemar, Anders1 aErnest, S., K. Morgan1 aEscribano, Rubén1 aEstiarte, Marc1 aEvans, Brian, S.1 aFan, Tung-Yung1 aFarah, Fabiano, Turini1 aFernandes, Luiz, Loureiro1 aFarneda, Fábio, Z.1 aFidelis, Alessandra1 aFitt, Robert1 aFosaa, Anna, Maria1 aFranco, Geraldo, Antonio Da1 aFrank, Grace, E.1 aFraser, William, R.1 aGarcía, Hernando1 aGatti, Roberto, Cazzolla1 aGivan, Or1 aGorgone-Barbosa, Elizabeth1 aGould, William, A.1 aGries, Corinna1 aGrossman, Gary, D.1 aGutierréz, Julio, R.1 aHale, Stephen1 aHarmon, Mark, E.1 aHarte, John1 aHaskins, Gary1 aHenshaw, Donald, L.1 aHermanutz, Luise1 aHidalgo, Pamela1 aHiguchi, Pedro1 aHoey, Andrew1 aVan Hoey, Gert1 aHofgaard, Annika1 aHoleck, Kristen1 aHollister, Robert, D.1 aHolmes, Richard1 aHoogenboom, Mia1 aHsieh, Chih-hao1 aHubbell, Stephen, P.1 aHuettmann, Falk1 aHuffard, Christine, L.1 aHurlbert, Allen, H.1 aIvanauskas, Natália, Macedo1 aJaník, David1 aJandt, Ute1 aJażdżewska, Anna1 aJohannessen, Tore1 aJohnstone, Jill1 aJones, Julia1 aJones, Faith, A. M.1 aKang, Jungwon1 aKartawijaya, Tasrif1 aKeeley, Erin, C.1 aKelt, Douglas, A.1 aKinnear, Rebecca1 aKlanderud, Kari1 aKnutsen, Halvor1 aKoenig, Christopher, C.1 aKortz, Alessandra, R.1 aKrál, Kamil1 aKuhnz, Linda, A.1 aKuo, Chao-Yang1 aKushner, David, J.1 aLaguionie-Marchais, Claire1 aLancaster, Lesley, T.1 aLee, Cheol, Min1 aLefcheck, Jonathan, S.1 aLévesque, Esther1 aLightfoot, David1 aLloret, Francisco1 aLloyd, John, D.1 aLópez-Baucells, Adrià1 aLouzao, Maite1 aMadin, Joshua, S.1 aMagnússon, Borgþór1 aMalamud, Shahar1 aMatthews, Iain1 aMcFarland, Kent, P.1 aMcGill, Brian1 aMcKnight, Diane, M.1 aMcLarney, William, O.1 aMeador, Jason1 aMeserve, Peter, L.1 aMetcalfe, Daniel, J.1 aMeyer, Christoph, F. J.1 aMichelsen, Anders1 aMilchakova, Nataliya1 aMoens, Tom1 aMoland, Even1 aMoore, Jon1 aMoreira, Carolina, Mathias1 aMüller, Jörg1 aMurphy, Grace1 aMyers-Smith, Isla, H.1 aMyster, Randall, W.1 aNaumov, Andrew1 aNeat, Francis1 aNelson, James, A.1 aNelson, Michael, Paul1 aNewton, Stephen, F.1 aNorden, Natalia1 aOliver, Jeffrey, C.1 aOlsen, Esben, M.1 aOnipchenko, Vladimir, G.1 aPabis, Krzysztof1 aPabst, Robert, J.1 aPaquette, Alain1 aPardede, Sinta1 aPaterson, David, M.1 aPélissier, Raphaël1 aPeñuelas, Josep1 aPérez-Matus, Alejandro1 aPizarro, Oscar1 aPomati, Francesco1 aPost, Eric1 aPrins, Herbert, H. T.1 aPriscu, John, C.1 aProvoost, Pieter1 aPrudic, Kathleen, L.1 aPulliainen, Erkki1 aRamesh, B., R.1 aRamos, Olivia, Mendivil1 aRassweiler, Andrew1 aRebelo, Jose, Eduardo1 aReed, Daniel, C.1 aReich, Peter, B.1 aRemillard, Suzanne, M.1 aRichardson, Anthony, J.1 aRichardson, Paul1 avan Rijn, Itai1 aRocha, Ricardo1 aRivera-Monroy, Victor, H.1 aRixen, Christian1 aRobinson, Kevin, P.1 aRodrigues, Ricardo, Ribeiro1 aRossa-Feres, Denise, de Cerquei1 aRudstam, Lars1 aRuhl, Henry1 aRuz, Catalina, S.1 aSampaio, Erica, M.1 aRybicki, Nancy1 aRypel, Andrew1 aSal, Sofia1 aSalgado, Beatriz1 aSantos, Flavio, A. M.1 aSavassi-Coutinho, Ana, Paula1 aScanga, Sara1 aSchmidt, Jochen1 aSchooley, Robert1 aSetiawan, Fakhrizal1 aShao, Kwang-Tsao1 aShaver, Gaius, R.1 aSherman, Sally1 aSherry, Thomas, W.1 aSiciński, Jacek1 aSievers, Caya1 ada Silva, Ana, Carolina1 ada Silva, Fernando, Rodrigues1 aSilveira, Fabio, L.1 aSlingsby, Jasper1 aSmart, Tracey1 aSnell, Sara, J.1 aSoudzilovskaia, Nadejda, A.1 aSouza, Gabriel, B. G.1 aSouza, Flaviana, Maluf1 aSouza, Vinícius, Castro1 aStallings, Christopher, D.1 aStanforth, Rowan1 aStanley, Emily, H.1 aSterza, José, Mauro1 aStevens, Maarten1 aStuart-Smith, Rick1 aSuarez, Yzel, Rondon1 aSupp, Sarah uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/geb.1272901794nas a2200181 4500008004100000245015800041210006900199260001200268300001400280490000600294520113500300100002201435700002101457700001601478700002201494700002401516856007201540 2018 eng d00aCatch and release: Hyporheic retention and mineralization of N-fixing Nostoc sustains downstream microbial mat biomass in two polar desert streams0 aCatch and release Hyporheic retention and mineralization of Nfix c07/2018 a357 - 3640 v33 a

 

Much work has been performed to investigate controls on nitrogen (N) uptake in streams, yet the fate of assimilated N is comparatively poorly resolved. Here, we use in-stream fixed N as an isotopic tracer to study the fate of assimilated N in glacial meltwater streams. We characterized d15N signatures of Oscillatorean, Chlorophyte, and N-fixing Nostoc mats over the lengths of two streams, and transported particulate organic matter (POM) in one. POM was isotopically most similar to Nostoc, which always had values near the atmospheric standard, suggesting N-fixation. Other mat types were depleted upstream, and became progressively enriched downstream, indicating a shift in N source. These results collectively show that Nostoc-derived N is mobilized, mineralized, and increasingly assimilated downstream as more depleted glacier-derived N is exhausted, demonstrating the importance of organic matter processing to balancing elemental budgets, and improving our understanding of nutrient cycling in lotic environments.

 

1 aKohler, Tyler, J.1 aStanish, Lee, F.1 aLiptzin, D.1 aBarrett, John, E.1 aMcKnight, Diane, M. uhttps://aslopubs.onlinelibrary.wiley.com/doi/abs/10.1002/lol2.1008702146nas a2200193 4500008004100000245011200041210006900153260001200222490000600234520149600240653001501736653002101751653002701772653002501799653001901824100001901843700001701862856007301879 2018 eng d00aDissolved Trace and Minor Elements in Cryoconite Holes and Supraglacial Streams, Canada Glacier, Antarctica0 aDissolved Trace and Minor Elements in Cryoconite Holes and Supra c04/20180 v63 a

 

We present a synthesis of the trace element chemistry in melt on the surface Canada Glacier, Taylor Valley, McMurdo Dry Valleys (MDV), Antarctica (∼78◦S). The MDV is largely ice-free. Low accumulation rates, strong winds, and proximity to the valley floor make these glaciers dusty in comparison to their inland counterparts. This study examines both supraglacial melt streams and cryoconite holes. Supraglacial streams on the lower Canada Glacier have median dissolved (<0.4 μm) concentrations of Fe, Mn, As, Cu, and V of 71.5, 75.5, 3.7, 4.6, and 4.3 nM. All dissolved Cd concentrations and the vast majority of Pb values are below our analytical detection (i.e., 0.4 and 0.06 nM). Chemical behavior did not follow similar trends for eastern and western draining waters. Heterogeneity likely reflects distinctions eolian deposition, rock:water ratios, and hydrologic connectivity. Future increases in wind-delivered sediment will likely drive dynamic responses in melt chemistry. For elements above detection limits, dissolved concentrations in glacier surface melt are within an order of magnitude of concentrations observed in proglacial streams (i.e., flowing on the valley floor). The Fe enrichment of cryoconite water relative to N, P, or Si exceeds enrichment observed in marine phytoplankton. This suggests that the glacier surface is an important source of Fe to downstream ecosystems.

 

10aAntarctica10acryoconite holes10aglacier melt chemistry10asupraglacial streams10atrace elements1 aFortner, Sarah1 aLyons, Berry uhttp://journal.frontiersin.org/article/10.3389/feart.2018.00031/full01630nas a2200169 4500008004100000245008200041210006900123260001200192490000600204520109200210100002201302700002401324700002101348700001701369700001601386856005801402 2018 eng d00aDrivers of solar radiation variability in the McMurdo Dry Valleys, Antarctica0 aDrivers of solar radiation variability in the McMurdo Dry Valley c03/20180 v83 a

 

Annually averaged solar radiation in the McMurdo Dry Valleys, Antarctica has varied by over 20 W m−2 during the past three decades; however, the drivers of this variability are unknown. Because small differences in radiation are important to water availability and ecosystem functioning in polar deserts, determining the causes are important to predictions of future desert processes. We examine the potential drivers of solar variability and systematically eliminate all but stratospheric sulfur dioxide. We argue that increases in stratospheric sulfur dioxide increase stratospheric aerosol optical depth and decrease solar intensity. Because of the polar location of the McMurdo Dry Valleys (77–78°S) and relatively long solar ray path through the stratosphere, terrestrial solar intensity is sensitive to small differences in stratospheric transmissivity. Important sources of sulfur dioxide include natural (wildfires and volcanic eruptions) and anthropogenic emission.

 

1 aObryk, Maciek, K.1 aFountain, Andrew, G1 aDoran, Peter, T.1 aLyons, Berry1 aEastman, R. uhttp://www.nature.com/articles/s41598-018-23390-7.pdf02262nas a2200181 4500008004100000022001400041245010300055210006900158260001200227300001600239490000800255520165500263100002201918700001701940700001501957700002401972856008401996 2018 eng d a2169-895300aFe and Nutrients in Coastal Antarctic Streams: Implications for Primary Production in the Ross Sea0 aFe and Nutrients in Coastal Antarctic Streams Implications for P c12/2018 a3507 - 35220 v1233 a

The Southern Ocean (SO) has been an area of biogeochemical interest due to the presence of macronutrients (N, P, and Si) but lack of the expected primary production response, which is thought to be primarily due to Fe limitation. Because primary production is associated with increased drawdown of atmospheric CO2, it is important to quantify the fluxes of Fe and other nutrients into the SO. Here we present data from subaerial streams that flow into the Ross Sea, a sector of the coastal SO. Water samples were collected in the McMurdo Dry Valleys, Antarctica, and analyzed for macronutrients and Fe to determine the potential impact of terrestrial water input on the biogeochemistry of coastal oceanic waters. The physiochemical forms of Fe were investigated through analysis of three operationally defined forms: acid-dissolvable Fe (no filtration), filterable Fe (<0.4 μm), and dissolved Fe (<0.2 μm). The combined average flux from two McMurdo Dry Valley streams was approximately 240 moles of filterable Fe per year. The dissolved fraction of Fe made up 18%–27% of the filterable Fe. The stream data yield an average filterable stoichiometry of N3P1Si100Fe0.8, which is substantially different from the planktonic composition and suggests that these streams are a potential source of Fe and P, relative to N and Si, to coastal phytoplankton communities. While the Fe flux from these streams is orders of magnitude less than estimated eolian and iceberg sources, terrestrial streams are expected to become a more significant source of Fe to the Ross Sea in the future.

1 aOlund, Sydney, A.1 aLyons, Berry1 aWelch, Sue1 aWelch, Kathleen, A. uhttps://agupubs.pericles-prod.literatumonline.com/doi/full/10.1029/2017JG00435202094nas a2200241 4500008004100000245014400041210006900185260001200254490000600266520131100272653002001583653001401603653001701617653001501634653001501649653002401664653001301688653002201701100001701723700002201740700002401762856006601786 2018 eng d00aThe impact of fossil fuel burning related to scientific activities in the McMurdo Dry Valleys, Antarctica: Revisited0 aimpact of fossil fuel burning related to scientific activities i c04/20180 v63 a

 

Fossil fuel use associated with scienti c activities in the Taylor Valley, Antarctic has been examined to determine the fluxes of particulate organic and elemental carbon and nitrogen as well as NOx for the 2015–2016 austral summer field season. These carbon and nitrogen fluxes are compared to our previously published calculations for the 1997–1998 austral summer. In addition, we compile fossil fuel usage and resulting C and N fluxes from the major field camp in Taylor Valley, Lake Hoare Camp (LHC) from the late 1990’s through 2017. In general, the annual fluxes do vary from year to year, but there is no significant trend, at least during the primary summer field season. There is indication that increasing the length of scientific operations does increase the C and N inputs via fossil fuel burning. This works supports our original results demonstrating that over long periods of time the anthropogenic flux of N from local fossil fuel burning could become quantitatively important in the region. Although the particulate C fluxes remain very low, the recent finding of black carbon in the Taylor Valley landscape indicates more on-going monitoring of the source of this material is merited.

 

10acarbon dynamics10aemissions10afossil fuels10ahelicopter10amanagement10aMcMurdo Dry Valleys10anitrogen10ascience activites1 aLyons, Berry1 aSaelens, Elsa, D.1 aWelch, Kathleen, A. uhttps://www.elementascience.org/article/10.1525/elementa.288/04038nas a2200205 4500008004100000245015700041210006900198260001200267300001600279490000800295520333900303100001903642700002103661700002403682700001503706700002403721700001703745700002403762856004603786 2018 eng d00aNear-surface refractory black carbon observations in the atmosphere and snow in the McMurdo Dry Valleys, Antarctica and potential impacts of foehn winds0 aNearsurface refractory black carbon observations in the atmosphe c01/2018 a2877 - 28870 v1233 a

Measurements of light absorbing particles in the boundary layer of the high southern latitudes are scarce, particularly in the McMurdo Dry Valleys (MDV), Antarctica. During the 2013 - 2014 austral summer near-surface boundary layer refractory black carbon (rBC) aerosols were measured in air by a single particle soot photometer (SP2) at multiple locations in the MDV. Near-continuous rBC atmospheric measurements were collected at Lake Hoare Camp (LH) over two months and for several hours at more remote locations away from established field camps. We investigated periods dominated by both up and down-valley winds to explore the causes of differences in rBC concentrations and size distributions. Snow samples were also collected in a 1m pit on a glacier near the camp. The range of concentrations rBC in snow were 0.3 1.2 ± 0.3 μg-rBC/L-H2O, and total organic carbon were 0.3 1.4 ± 0.3 mg/L. The rBC concentrations measured in this snow pit are not sufficient to reduce surface albedo, however, there is potential for accumulation of rBC on snow and ice surfaces at low elevation throughout the MDV which were not measured as part of this study. At LH, the average background rBC mass aerosol concentrations was 1.3 ng/m3. rBC aerosol mass concentrations were slightly lower, 0.09 1.3 ng/m3, at the most remote sites in the MDV. Concentration spikes as high as 200 ng/m3 were observed at LH, associated with local activities. During a foehn wind event, the average rBC mass concentration increased to 30-50 ng m-3. Here we show the rBC increase could be due to resuspension of locally produced BC from generators, rocket toilets, and helicopters, which may remain on the soil surface until redistributed during high wind events. Quantification of local production and long-range atmospheric transport of rBC to the MDV is necessary for understanding the impacts of this species on regional climate. 

 

1 aKhan, Alia, L.1 aMcMeeking, Gavin1 aSchwarz, Joshua, P.1 aXian, Peng1 aWelch, Kathleen, A.1 aLyons, Berry1 aMcKnight, Diane, M. uhttp://doi.wiley.com/10.1002/2017JD02769602332nas a2200193 4500008004100000245017900041210006900220260001200289300001600301490000700317520164300324100001701967700001701984700002202001700001702023700002302040700002002063856005502083 2018 eng d00aStable C and N isotope ratios reveal soil food web structure and identify the nematode Eudorylaimus antarcticus as an omnivore–predator in Taylor Valley, Antarctica0 aStable C and N isotope ratios reveal soil food web structure and c05/2018 a1013–10180 v413 a

Soil food webs of the McMurdo Dry Valleys, Antarctica are simple. These include primary trophic levels of mosses, algae, cyanobacteria, bacteria, archaea, and fungi, and their protozoan and metazoan consumers (including relatively few species of nematodes, tardigrades, rotifers, and microarthropods). These biota are patchily distributed across the landscape, with greatest faunal biodiversity associated with wet soil. Understanding trophic structure is critical to studies of biotic interactions and distribution; yet, McMurdo Dry Valley soil food web structure has been inferred from limited laboratory culturing and micro- scopic observations. To address this, we measured stable isotope natural abundance ratios of C (13C/12C) and N (15N/14N) for di erent metazoan taxa (using whole body biomass) to determine soil food web structure in Taylor Valley, Antarctica. Nitrogen isotopes were most useful in di erentiating trophic levels because they fractionated predictably at higher trophic levels. Using 15N/14N, we found that three trophic levels were present in wet soil habitats. While cyanobacterial mats were the primary trophic level, the nematode Plectus murrayi, tardigrade Acutuncus antarcticus, and rotifers composed a secondary trophic level of grazers. Eudorylaimus antarcticus had a 15N/14N ratio that was 2–4‰ higher than that of grazers, indicating that this species is the sole member of a tertiary trophic level. Understanding the trophic positions of soil fauna is critical to predictions of current and future species interactions and their distributions for the McMurdo Dry Valleys, Antarctica.

1 aShaw, Ashley1 aAdams, Byron1 aBarrett, John, E.1 aLyons, Berry1 aVirginia, Ross, A.1 aWall, Diana, H. uhttp://link.springer.com/10.1007/s00300-017-2243-801835nas a2200169 4500008004100000245013700041210006900178260001200247300001800259490000700277520122000284100002101504700002501525700002401550700001701574856007401591 2018 eng d00aTransit times and rapid chemical equilibrium explain chemostasis in glacial meltwater streams in the McMurdo Dry Valleys, Antarctica0 aTransit times and rapid chemical equilibrium explain chemostasis c12/2018 a13322 - 133310 v453 a

Fluid  transit  time  is  understood  to  be  an  important  control  on  the  shape  of concentration-discharge (C-q) relationships, yet empirical evidence supporting this linkage is limited. We investigated C-q relationships for weathering-derived solutes across seven Antarctic glacial meltwate streams. We hypothesized that (H1) solute fluxes in McMurdo Dry Valley streams are reaction limited so that C-q relationships are characterized by dilution and that (H2) transit time explains between-stream variability in the degree of C-q dilution. Results show that C-q relationships are chemostatic because solute equilibrium times are shorter than stream corridor fluid transit times. Between-stream variability in the efficiency of solute production is positively correlated with transit time, suggesting that transit time is an important control on the solute export regime. These results provide empirical evidence for the controls on weathering-derived C-q relationships and have important implications for Antarctic ecosystems and solute export regimes of watersheds worldwide.

1 aWlostowski, Adam1 aGooseff, Michael, N.1 aMcKnight, Diane, M.1 aLyons, Berry uhttps://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018GL08036902937nas a2200157 4500008004100000245006000041210006000101260001200161300001400173490000700187520246500194100001702659700001402676700002402690856006502714 2017 eng d00aCa isotopic geochemistry of an Antarctic aquatic system0 aCa isotopic geochemistry of an Antarctic aquatic system c01/2017 a882 - 8910 v443 a

The McMurdo Dry Valleys, Antarctica, are a polar desert ecosystem. The hydrologic system of the dry valleys is linked to climate with ephemeral streams that flow from glacial melt during the austral summer. Past climate variations have strongly influenced the closed-basin, chemically stratified lakes on the valley floor. Results of previous work point to important roles for both in-stream processes (e.g., mineral weathering, precipitation and dissolution of salts) and in-lake processes (e.g., mixing with paleo-seawater and calcite precipitation) in determining the geochemistry of these lakes. These processes have a significant influence on calcium (Ca) biogeochemistry in this aquatic ecosystem, and thus variations in Ca stable isotope compositions of the waters can aid in validating the importance of these processes. We have analyzed the Ca stable isotope compositions of streams and lakes in the McMurdo Dry Valleys. The results validate the important roles of weathering of aluminosilicate minerals and/or CaCO3 in the hyporheic zone of the streams, and mixing of lake surface water with paleo-seawater and precipitation of Ca-salts during cryo-concentration events to form the deep lake waters. The lakes in the McMurdo Dry Valleys evolved following different geochemical pathways, evidenced by their unique, nonsystematic Ca isotope signatures. 

1 aLyons, Berry1 aBullen, T1 aWelch, Kathleen, A. uhttp://onlinelibrary.wiley.com/doi/10.1002/2016GL071169/full02880nas a2200625 4500008004100000245007400041210006900115260001200184490000800196520106500204100002301269700002101292700002101313700001601334700001801350700002301368700002201391700002301413700002201436700002001458700002701478700002001505700002301525700002801548700002301576700002201599700002101621700002401642700002001666700002401686700001601710700001501726700001801741700002201759700002701781700001901808700002401827700002201851700002101873700002801894700002201922700002201944700001701966700002101983700001902004700002202023700001802045700002702063700002302090700002302113700002202136700001602158700003202174856004802206 2017 eng d00aA communal catalogue reveals Earth’s multiscale microbial diversity0 acommunal catalogue reveals Earth s multiscale microbial diversit c11/20170 v5513 a

Our growing awareness of the microbial world’s importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth’s microbial diversity.

1 aThompson, Luke, R.1 aSanders, Jon, G.1 aMcDonald, Daniel1 aAmir, Amnon1 aLadau, Joshua1 aLocey, Kenneth, J.1 aPrill, Robert, J.1 aTripathi, Anupriya1 aGibbons, Sean, M.1 aAckermann, Gail1 aNavas-Molina, Jose, A.1 aJanssen, Stefan1 aKopylova, Evguenia1 aVázquez-Baeza, Yoshiki1 aGonzález, Antonio1 aMorton, James, T.1 aMirarab, Siavash1 aXu, Zhenjiang, Zech1 aJiang, Lingjing1 aHaroon, Mohamed, F.1 aKanbar, Jad1 aZhu, Qiyun1 aSong, Se, Jin1 aKosciolek, Tomasz1 aBokulich, Nicholas, A.1 aLefler, Joshua1 aBrislawn, Colin, J.1 aHumphrey, Gregory1 aOwens, Sarah, M.1 aHampton-Marcell, Jarrad1 aBerg-Lyons, Donna1 aMcKenzie, Valerie1 aFierer, Noah1 aFuhrman, Jed, A.1 aClauset, Aaron1 aStevens, Rick, L.1 aShade, Ashley1 aPollard, Katherine, S.1 aGoodwin, Kelly, D.1 aJansson, Janet, K.1 aGilbert, Jack, A.1 aKnight, Rob1 aConsortium, The, Earth Micr uhttps://www.nature.com/articles/nature2462102219nas a2200133 4500008004100000245013600041210006900177260004400246490000900290520170700299100002502006700001702031856003702048 2017 eng d00aComparing the Weathering Environment of Permian and Modern Antarctic Proglacial Lake Sediments: Mineralogical and Geochemical Study0 aComparing the Weathering Environment of Permian and Modern Antar aColumbus, OHbThe Ohio State University0 vB.S.3 a

The Antarctic continent has been in a polar to subpolar position since the Permian period. Although it has experienced milder climates over this time period as evidenced by corals in the fossil record, Antarctica did undergo extensive glaciation during the Permian. This is based on the abundance of Permian tillites (sedimentary rocks derived from glacier tills) found in the Transantarctic Mountains. In this research, I have compared Permian age proglacial lake sediments that are associated with tilites to modern proglacial lake siltstones and mudstones from Antarctica. This was done to determine the climate, especially the amount of glacier melt that occurred when these Permian sediments were deposited. The modern lake sediments are deposited in perennially ice-covered lakes by ephemeral streams that only flow 6 to 12 weeks a year. The geochemical analyses of the Permian samples and the modern sediments from Lake Hoare in the McMurdo Dry Valleys suggest that the Permian samples are more highly chemically weathered than the modern sediments. The mineralogy of Lake Hoare sediments contain more primary minerals than chemical weathering produced minerals in the Pagoda Formation rocks, thus supporting the geochemical analysis that the Pagoda Formation minerals have been more weathered. All these data suggest that the Permian lake samples were deposited in a warmer, more hydrogeologically active environment than were the modern lake sediments. These data support previously published sedimentological and paleontological data that the Pagoda samples were deposited under more temperate or warm-based proglacial conditions than what is observed in the McMurdo Dry Valleys today.

1 aBrewster, Shelby, A.1 aLyons, Berry uhttp://hdl.handle.net/1811/8076300851nas a2200265 4500008004100000245009100041210006900132260001200201300001400213490000600227100002500233700002200258700001700280700002100297700002400318700001700342700002400359700002100383700002000404700003300424700003100457700002300488700002000511856005400531 2017 eng d00aDecadal ecosystem response to an anomalous melt season in a polar desert in Antarctica0 aDecadal ecosystem response to an anomalous melt season in a pola c09/2017 a1334-13380 v11 aGooseff, Michael, N.1 aBarrett, John, E.1 aAdams, Byron1 aDoran, Peter, T.1 aFountain, Andrew, G1 aLyons, Berry1 aMcKnight, Diane, M.1 aPriscu, John, C.1 aSokol, Eric, R.1 aTakacs-Vesbach, Cristina, D.1 aVandegehuchte, Martijn, L.1 aVirginia, Ross, A.1 aWall, Diana, H. uhttps://www.nature.com/articles/s41559-017-0253-002279nas a2200133 4500008004100000245013700041210006900178260004800247490000900295520174300304100001902047700002102066856005802087 2017 eng d00aEvidence of subglacial brine inflow and wind-induced mixing from high resolution temperature measurements in Lake Bonney, Antarctica0 aEvidence of subglacial brine inflow and windinduced mixing from  aBaton Rouge, LAbLouisiana State University0 vM.S.3 a

Hypersaline brine beneath Taylor Glacier enters proglacial West Lobe Lake Bonney (WLB) subglacially as well as from Blood Falls, a surface discharge point at the Taylor Glacier terminus. The brine strongly influences the water column of WLB. Because of the extremely high salinities below the chemocline in WLB, density is determined almost entirely by salinity and temperature can be used as a passive tracer. Cold brine intrusions enter WLB at the glacier face and intrude in to the water column at the depth of neutral buoyancy, where they can be identified by anomalously cold temperatures at that depth. This study is the first to definitively identify subglacial brine intrusions in WLB, since the absence of an open water moat in the winter prevents brine entry from the surface at Blood Falls. High resolution thermistors and CTDs deployed year-round beneath the perennial ice cover demonstrate that brine intrusions can influence the thermal stratification of the water column near the glacier terminus for the majority of the year, and that the effects diminish with distance from the glacier terminus. High volumes of brine inflow alter the density stratification of the water column at the depth of the intrusion and cause turbulent mixing near the glacier terminus. High resolution measurements also reveal internal water movements associated with katabatic wind events, a novel finding that challenges long held assumptions about the stability of the WLB water column. The long term records of Blood Falls flow and of temperature anomalies in WLB indicate that brine release from the subglacial system has been a persistent feature in the region for decades, with implications for the geochemistry and biology of WLB.

1 aLawrence, Jade1 aDoran, Peter, T. uhttps://digitalcommons.lsu.edu/gradschool_theses/434302715nas a2200133 4500008004100000245011000041210006900151260002600220490000900246520222000255100002202475700001702497856006702514 2017 eng d00aFe and Nutrients in Coastal Antarctic Streams: Implications for Marine Primary Production in the Ross Sea0 aFe and Nutrients in Coastal Antarctic Streams Implications for M bOhio State University0 vM.S.3 a

The Southern Ocean (SO) has been an area of much biogeochemical interest due to the role of Fe limitation for primary production. Primary production is associated with increased carbon sequestration, making it important to characterize and quantify the fluxes of Fe and other nutrients to the ocean. Water samples were collected in the McMurdo Dry Valleys, Antarctica (MDV) from four subaerial streams flowing into the Ross Sea. They were analyzed for macronutrients (N, P, Si) and Fe to determine the potential impact of terrestrial water input on the biogeochemistry of coastal oceanic waters. Our stream data yield an average filterable composition of N3P1 Si100Fe0.8, which is substantially different from the planktonic composition as demonstrated by empirical measurements, and suggests that these streams are a potential source of Fe and P, relative to N and Si, to coastal phytoplankton communities.

The behavior and potential colloidal/nanoparticulate speciation of the Fe in these streams was investigated through analysis of three physiochemical forms of Fe - environmentally active Fe (acid-soluble/no filtration), filterable Fe (filtered through 0.4 μm), and dissolved Fe (filtered through 0.2 μm). It has been suggested that the dissolved fraction is mainly nanoparticulate and represents a more bioavailable form of Fe, as compared with colloids and particles. Overall, the combined average annual flux from two MDV streams is approximately 240 moles fFe yr-1, which is consistent with previously predicted values. The dissolved fraction of Fe (<0.2 μm) was between 18% and 27% percent of the fFe, meaning the fFe pool is mostly colloidal. While the Fe flux from these streams is several orders of magnitude less than aeolian and iceberg sources, terrestrial streams are expected to become a more significant source of Fe to the Ross Sea. As the Antarctic climate warms, ice-free regions similar to the MDV should increase in extent and glacier melt. This study questions how, and in what quantities, Fe is solubilized and transported from the landscape into the SO to better inform predictions of Fe fluxes following continued warming.
1 aOlund, Sydney, A.1 aLyons, Berry uhttp://rave.ohiolink.edu/etdc/view?acc_num=osu149269789434354600489nas a2200121 4500008004100000245011200041210006900153260004400222490000900266100002200275700001700297856005300314 2017 eng d00aThe geochemistry of minor cations within Antarctic stream water: Determining the role of the hyporheic zone0 ageochemistry of minor cations within Antarctic stream water Dete aColumbus, OHbThe Ohio State University0 vB.A.1 aSaelens, Elsa, D.1 aLyons, Berry uhttp://library.ohio-state.edu/record=b8218699~S701634nas a2200217 4500008004100000245010200041210006900143260001200212300001400224490000600238520092200244100002401166700002901190700002201219700002101241700002501262700002401287700001301311700002101324856007101345 2017 eng d00aHigh-resolution elevation mapping of the McMurdo Dry Valleys, Antarctica, and surrounding regions0 aHighresolution elevation mapping of the McMurdo Dry Valleys Anta c07/2017 a435 - 4430 v93 a

We present detailed surface elevation measurements for the McMurdo Dry Valleys, Antarctica derived from aerial lidar surveys flown in the austral summer of 2014–2015 as part of an effort to understand geomorphic changes over the past decade. Lidar return density varied from 2 to > 10 returns  m−2 with an average of about 5  returns  m−2. Vertical and horizontal accuracies are estimated to be 7 and 3 cm, respectively. In addition to our intended targets, other ad hoc regions were also surveyed including the Pegasus flight facility and two regions on Ross Island, McMurdo Station, Scott Base (and surroundings), and the coastal margin between Cape Royds and Cape Evans. These data are included in this report and data release. The combined data are freely available at https://doi.org/10.5069/G9D50JX3.

1 aFountain, Andrew, G1 aFernandez-Diaz, Juan, C.1 aObryk, Maciek, K.1 aLevy, Joseph, S.1 aGooseff, Michael, N.1 aVan Horn, David, J.1 aMorin, P1 aShrestha, Ramesh uhttps://www.earth-syst-sci-data.net/9/435/2017/essd-9-435-2017.pdf02691nas a2200229 4500008004100000022001400041245015500055210006900210260001200279490000700291520189400298653003402192653001902226653002402245653002202269653002302291100002202314700001202336700002002348700002902368856006402397 2017 eng d a0722-406000aImpact of nitrogen and phosphorus on phytoplankton production and bacterial community structure in two stratified Antarctic lakes: a bioassay approach0 aImpact of nitrogen and phosphorus on phytoplankton production an c05/20170 v403 a

Arctic, Antarctic, and alpine ecosystems are recognized as sensors and sentinels of global change. As a consequence of their high sensitivity to minor climatic perturbations, permanently ice-covered lakes located in the McMurdo Dry Valleys (MDV), Antarctica, represent end members in the global network of inland bodies of water. Episodic climatic events in the form of increased summer glacial melt result in inputs of organic sediment and nutrients from glacial streams to these closed basins. Phytoplankton communities residing in the oligotrophic water columns are highly responsive to pulses in nutrient availability; however, there is a lack of understanding on whether specific phytoplankton groups are more competitive during a summer flood event and how shifts in the phytoplankton community may influence heterotrophic bacteria. A bioassay approach in 3-l bottles was used to investigate the influence of inorganic nitrogen and phosphorus availability on planktonic communities from the oligotrophic upper waters of two chemically distinct MDV lakes (Lakes Bonney and Fryxell) which differ in their external inputs and water column N/P stoichiometry. While microbial community responses varied between lakes and were nutrient-dependent, stimulation of phytoplankton biomass and productivity across all treatments was strongly linked with increased abundance of a single phytoplankton phylum (Chlorophyta). Despite stimulation of phytoplankton growth, primary and bacterial productivity was generally uncoupled; however, shifts in bacterial community diversity were observed in bioassays amended with either P or NP. We suggest that climate-associated increases in phytoplankton production and concomitant shifts in diversity will influence MDV bacterial community structure by altering the availability and composition of autochthonous carbon for heterotrophic production.

10aAlgal–bacteria interactions10aclimate change10aMcMurdo Dry Valleys10aNutrient bioassay10aPrimary production1 aTeufel, Amber, G.1 aLi, Wei1 aKiss, Andor, J.1 aMorgan-Kiss, Rachael, M. uhttps://link.springer.com/article/10.1007/s00300-016-2025-802255nas a2200193 4500008004100000245007900041210006900120260001200189300001400201490000800215520163600223100002001859700002501879700002401904700002101928700002201949700002401971856006601995 2017 eng d00aImpacts of permafrost degradation on a stream in Taylor Valley, Antarctica0 aImpacts of permafrost degradation on a stream in Taylor Valley A c05/2017 a205 - 2130 v2853 a

The McMurdo Dry Valleys (MDV) of Antarctica are an ice-free landscape that supports a complex, microbially dominated ecosystem despite a severely arid, cold environment (b 5 cm water equivalent/y, − 18 °C mean annual air temperature). Recent observations of permafrost degradation in the coastal zones of the MDV suggest that this region is nearing a threshold of rapid landscape change. In 2012, substantial thermokarst development was observed along several kilometers of the west branch of Crescent Stream in Taylor Valley mostly in the form of bank failures, whereas the adjacent east branch was unaffected. The objective of this study was to quantify the changes to the stream banks of the west branch of Crescent Stream and to determine the impacts on the composition of the stream bed material. Three annually repeated terrestrial LiDAR scans were compared to determine the rates of ground surface change caused by thermokarst formation on the stream bank. The areal extent of the thermokarst was shown to be decreasing; however, the average vertical rate of retreat remained constant. Field measurements of bed materials indicated that the west branch and the reach downstream of the confluence (of east and west branches) consistently contained more fines than the unaffected east branch. This suggests that the finer bed material is a result of the thermokarst development on the west branch. These finer bed material compositions are likely to increase the mobility of the bed material, which will have implications for stream morphology, stream algal mat communities, and downstream aquatic ecosystems.

1 aSudman, Zachary1 aGooseff, Michael, N.1 aFountain, Andrew, G1 aLevy, Joseph, S.1 aObryk, Maciek, K.1 aVan Horn, David, J. uhttp://linkinghub.elsevier.com/retrieve/pii/S0169555X1630846702127nas a2200217 4500008004100000245010900041210006900150260001200219300001600231490000700247520142800254100001501682700001801697700003301715700001601748700002001764700002001784700002101804700001601825856006801841 2017 eng d00aNiche specialization of bacteria in permanently ice-covered lakes of the McMurdo Dry Valleys, Antarctica0 aNiche specialization of bacteria in permanently icecovered lakes c06/2017 a2258 - 22710 v193 a

Perennially ice‐covered lakes in the McMurdo Dry Valleys, Antarctica, are chemically stratified with depth and have distinct biological gradients. Despite long‐term research on these unique environments, data on the structure of the microbial communities in the water columns of these lakes are scarce. Here, we examined bacterial diversity in five ice‐covered Antarctic lakes by 16S rRNA gene‐based pyrosequencing. Distinct communities were present in each lake, reflecting the unique biogeochemical characteristics of these environments. Further, certain bacterial lineages were confined exclusively to specific depths within each lake. For example, candidate division WM88 occurred solely at a depth of 15 m in Lake Fryxell, whereas unknown lineages of Chlorobi were found only at a depth of 18 m in Lake Miers, and two distinct classes of Firmicutes inhabited East and West Lobe Bonney at depths of 30 m. Redundancy analysis revealed that community variation of bacterioplankton could be explained by the distinct conditions of each lake and depth; in particular, assemblages from layers beneath the chemocline had biogeochemical associations that differed from those in the upper layers. These patterns of community composition may represent bacterial adaptations to the extreme and unique biogeochemical gradients of ice‐covered lakes in the McMurdo Dry Valleys.

1 aKwon, Miye1 aKim, Mincheol1 aTakacs-Vesbach, Cristina, D.1 aLee, Jaejin1 aHong, Soon, Gyu1 aKim, Sang, Jong1 aPriscu, John, C.1 aKim, Ok-Sun uhttps://onlinelibrary.wiley.com/doi/pdf/10.1111/1462-2920.1372103009nas a2200133 4500008004100000245011500041210006900156260002600225490000900251520251000260100002102770700001702791856006702808 2017 eng d00aSpatial and Temporal Geochemical Characterization of Aeolian Material from the McMurdo Dry Valleys, Antarctica0 aSpatial and Temporal Geochemical Characterization of Aeolian Mat bOhio State University0 vM.S.3 a

Aeolian processes play an important role in the transport of both geological and biological materials globally, on the biogeochemistry of ecosystems, and in landscape evolution. As the largest ice free area on the Antarctic continent (approximately 4800 km2), the McMurdo Dry Valleys (MDV) are potentially a major source of aeolian material for Antarctica, but information on the spatial and temporal variability of this material is needed to understand its soluble and bulk geochemistry, deposition and source, and hence influence on ecosystem dynamics. 53 samples of aeolian material from Alatna Valley, Victoria Valley, Miers Valley, and Taylor Valley (Taylor Glacier, East Lake Bonney, F6 (Lake Fryxell), and Explorer’s Cove) were collected at five heights (5, 10, 20, 50, 100 cm) above the surface seasonally for 2013 through 2015. The sediment was analyzed for soluble solids, total and organic carbon, minerology, and bulk chemistry. Of the soluble component, the major anions varied between Cl- and HCO3-, and the major cation was Na+ for all sites. Soluble N:P ratios in the aeolian material reflect nutrient limitations seen in MDV soils, where younger, coastal soils are N-limited, while older, up valley soils are P-limited. Material from East Lake Bonney was P-limited in the winter samples, but N-limited in the full year samples, suggesting different sources of material based on season. Analysis of soluble salts in aeolian material in Taylor Valley compared to published soil literature demonstrates a primarily down valley transport of materials from Taylor Glacier towards the coast. The bulk chemistry suggests that the aeolian material is highly unweathered (CIA values less than 60 %), but scanning electron microscope images show alteration for some individual sediment grains. The mineralogy was reflective of local rocks, specifically the McMurdo Volcanics, Ferrar Dolerite, Beacon Sandstone and granite, but variations in major oxide percentages and rare earth element signatures could not be explained by mixing lines between these four rock types. This potentially suggests that there may be an additional, and possibly distant, source of aeolian material to the MDV that is not accounted for. This work provides the first fully elevated spatial and temporal analysis of the geochemistry of aeolian material from the Dry Valleys, and contributes to a better understanding of sediment provenance and how aeolian deposition may affect surface biological communities.

1 aDiaz, Melisa, A.1 aLyons, Berry uhttp://rave.ohiolink.edu/etdc/view?acc_num=osu150046821614772503797nas a2200157 4500008004100000245012100041210007100162260001200233300001600245490000700261520325100268100001703519700002403536700001703560856006203577 2017 eng d00aA temporal stable isotopic (δ18O, δD, d-excess) comparison in glacier meltwater streams, Taylor Valley, Antarctica0 atemporal stable isotopic δ18O δD dexcess comparison in glacier m c08/2017 a3069 - 30830 v313 a

In this paper, we describe the importance of hyporheic dynamics within Andersen Creek and Von Guerard Stream, Taylor Valley, Antarctica, from the 20102011 melt season using natural tracers. Water collection started at flow onset and continued, with weekly hyporheiczone sampling. The water δ18O and δD values were isotopically lighter in the beginning and heavier later in the season. Dexcess measurements were used as an indicator of mixing because an evaporative signature was evident and distinguishable between 2 primary endmembers (glacier meltwater and hyporheic zone). Hyporheiczone influence on the channel water was variable with a strong control on streamwater chemistry, except at highest discharges. This work supports previous research indicating that Von Guerard Stream has a large, widespread hyporheic zone that varies in size with time and discharge. Andersen Creek, with a smaller hyporheic zone, displayed hyporheiczone solute interaction through the influence from subsurface hypersaline flow. Overall, the evolution of Taylor Valley hyporheiczone hydrology is described seasonally. In midDecember, the hyporheic zone is a dynamic system exchanging with the glacier meltwater in the channel, and with diminishing flow in January, the hyporheic zone drains back into the channel flow also impacting stream chemistry. This work adds new information on the role of hyporheic zonestream interaction in these glacier meltwater streams. 

1 aLeslie, D.L.1 aWelch, Kathleen, A.1 aLyons, Berry uhttp://onlinelibrary.wiley.com/doi/10.1002/hyp.11245/full01407nas a2200445 4500008004100000245007700041210006900118260001200187490005900199100002200258700002400280700001900304700002100323700002100344700001900365700002400384700002000408700001700428700002400445700001700469700002300486700001900509700002100528700002000549700002100569700002200590700002300612700002500635700001800660700002200678700002300700700002300723700002500746700001800771700002000789700002400809700002600833700002500859856007700884 2016 eng d00aAerobiology Over Antarctica – A New Initiative for Atmospheric Ecology0 aAerobiology Over Antarctica A New Initiative for Atmospheric Eco c02/20160 v7767961946103149272350113651344451428464791101239365741 aPearce, David, A.1 aAlekhina, Irina, A.1 aTerauds, Aleks1 aWilmotte, Annick1 aQuesada, Antonio1 aEdwards, Arwyn1 aDommergue, Aurelien1 aSattler, Birgit1 aAdams, Byron1 aMagalhaes, Catarina1 aChu, Wan-Loy1 aLau, Maggie, C. Y.1 aCary, Craig, S1 aSmith, David, J.1 aWall, Diana, H.1 aEguren, Gabriela1 aMatcher, Gwynneth1 aBradley, James, A.1 ade Vera, Jean-Pierre1 aElster, Josef1 aHughes, Kevin, A.1 aCuthbertson, Lewis1 aBenning, Liane, G.1 aGunde-Cimerman, Nina1 aConvey, Peter1 aHong, Soon, Gyu1 aPointing, Steve, B.1 aPellizari, Vivian, H.1 aVincent, Warwick, F. uhttp://journal.frontiersin.org/Article/10.3389/fmicb.2016.00016/abstract00939nas a2200217 4500008004100000022001400041245011900055210006900174260001200243100001600255700002000271700002200291700002100313700002500334700002000359700002400379700001700403700002200420700002400442856025500466 2016 eng d a0722-406000aEvidence for dispersal and habitat controls on pond diatom communities from the McMurdo Sound Region of Antarctica0 aEvidence for dispersal and habitat controls on pond diatom commu c02/20161 aSakaeva, A.1 aSokol, Eric, R.1 aKohler, Tyler, J.1 aStanish, Lee, F.1 aSpaulding, Sarah, A.1 aHowkins, Adrian1 aWelch, Kathleen, A.1 aLyons, Berry1 aBarrett, John, E.1 aMcKnight, Diane, M. uhttp://link.springer.com/10.1007/s00300-016-1901-6http://link.springer.com/content/pdf/10.1007/s00300-016-1901-6http://link.springer.com/content/pdf/10.1007/s00300-016-1901-6.pdfhttp://link.springer.com/article/10.1007/s00300-016-1901-6/fulltext.html00639nas a2200205 4500008004100000245007600041210006900117260001200186300001300198490000700211100001700218700002500235700001700260700002400277700001700301700002500318700002100343700001700364856005200381 2016 eng d00aHydrological Controls on Ecosystem Dynamics in Lake Fryxell, Antarctica0 aHydrological Controls on Ecosystem Dynamics in Lake Fryxell Anta c07/2016 ae01590380 v111 aHerbei, Radu1 aRytel, Alexander, L.1 aLyons, Berry1 aMcKnight, Diane, M.1 aJaros, Chris1 aGooseff, Michael, N.1 aPriscu, John, C.1 aHewitt, Judi uhttp://dx.plos.org/10.1371/journal.pone.015903803056nas a2200133 4500008004100000245014700041210006900188260003900257490001000296520251200306100001202818700002902830856006302859 2016 eng d00aInfluence of environmental drivers and interactions on the microbial community structures in permanently stratified meromictic Antarctic lakes0 aInfluence of environmental drivers and interactions on the micro aOxford, OHbMiami Universityc20160 vPh.D.3 a

The microbial loop plays important roles in the cycling of energy, carbon and elements in aquatic ecosystems. Viruses, bacteria, Archaea and microbial eukaryotes are key players in global carbon cycle and biogeochemical cycles. Investigating microbial diversity and community structure is crucial first step for understanding the ecological functioning in aquatic environment. Meromictic lakes are bodies of water and exhibit permanent stratification of major physical and chemical environmental factors. Microbial consortia residing in permanently stratified lakes exhibit relatively constant spatial stratification throughout the water column and are adapted to vastly different habitats within the same water. Pristine perennially-ice-covered lakes (Lake Bonney, Lake Fryxell and Lake Vanda) are meromictic lakes located in the McMurdo Dry Valleys (MDV) of Southern Victoria Land, Antarctica. The lakes have isolated water bodies and extremely stable strata that vary physically, chemically, and biologically within and between the water columns. The unique characteristics support microbially dominated food webs in these lakes.

In the research presented here, we gathered new understanding of how environmental drivers influence microbial community structure in these aquatic ecosystems. We explored the lake microbial ecology from three major approaches: 1). Assess trophic activities in the natural environment and identify potential environmental drivers impacting heterotrophic (β Glucosaminidase) and autotrophic (Ribulose 1,5 bisphosphate carboxylase) enzyme activities; 2). Resolve the protist community composition (i.e. autotrophic, heterotrophic and mixotrophic groups) based on high throughput sequencing and bioinformatics. Identify how the community structures correlate with specific environmental and biological factors; 3). Reveal the diversity of potential microbial interactions between the microorganisms in the MDV lakes at individual cell level, and investigate how the interactions vary between organisms with different nutritional strategies.

Studies of polar microbial communities on the cusp of environmental change will be important for predicting how microbial communities in low latitude aquatic systems will respond. This study expands the understanding of how environmental drivers interact with microbial communities in the Antarctica lakes, and provide new information to predict how the community structure will alter as response to climate changes.

1 aLi, Wei1 aMorgan-Kiss, Rachael, M. uhttp://rave.ohiolink.edu/etdc/view?acc_num=miami146975731602462nas a2200193 4500008004100000022001300041245008800054210006900142260001600211300001400227490000800241520184200249100002102091700002202112700002302134700002502157700001502182856007102197 2016 eng d a0921818100aLake Vanda: A sentinel for climate change in the McMurdo Sound Region of Antarctica0 aLake Vanda A sentinel for climate change in the McMurdo Sound Re cJan-09-2016 a213 - 2270 v1443 a

Lake Vanda is a perennially ice-covered, meromictic, endorheic lake located in the McMurdo Dry Valleys of Antarctica, and an exceptional sentinel of climate change within the region. Lake levels rose 15 m over the past 68 years in response to climate-driven variability in ice-cover sublimation, meltwater production, and annual discharge of the Onyx River, the main source of water to the lake. Evidence from a new bathymetric map and water balance model combined with annual growth laminations in benthic mats suggest that the most recent filling trend began abruptly 80 years ago, in the early 1930s. This change increased lake volume by > 50%, triggered the formation of a new, upper, thermohaline convection cell, and cooled the lower convection cell by at least 2 °C and the bottom-most waters by at > 4 °C. Additionally, the depth of the deep chlorophyll a maximum rose by > 2 m, and deep-growing benthic algal mats declined while shallow benthic mats colonized freshly inundated areas. We attribute changes in hydrology to regional variations in air flow related to the strength and position of the Amundsen Sea Low (ASL) pressure system which have increased the frequency of down-valley, föhn winds associated with surface air temperature warming in the McMurdo Dry Valleys. The ASL has also been implicated in the recent warming of the Antarctic Peninsula, and provides a common link for climate-related change on opposite sides of the continent. If this trend persists, Lake Vanda should continue to rise and cool over the next 200 years until a new equilibrium lake level is achieved. Most likely, future lake rise will lead to isothermal conditions not conducive to thermohaline convection, resulting in a drastically different physical, biogeochemical, and biological structure than observed today.

1 aCastendyk, Devin1 aObryk, Maciek, K.1 aLeidman, Sasha, Z.1 aGooseff, Michael, N.1 aHawes, Ian uhttp://www.sciencedirect.com/science/article/pii/S092181811530014X02242nas a2200181 4500008004100000245012300041210006900164260001200233300001400245490000700259520163300266100002101899700002501920700002401945700001701969700001701986856005702003 2016 eng d00aPatterns of hydrologic connectivity in the McMurdo dry valleys, Antarctica: a synthesis of 20 years of hydrologic data0 aPatterns of hydrologic connectivity in the McMurdo dry valleys A c04/2016 a2958-29750 v303 a

Streams in the McMurdo Dry Valleys (MDVs) of Antarctica moderate an important hydrologic and biogeochemical connection between upland alpine glaciers, valley-bottom soils, and lowland closed-basin lakes. Moreover, MDV streams are simple but dynamic systems ideal for studying interacting hydrologic and ecological dynamics. This work synthesizes 20 years of hydrologic data, collected as part of the MDVs Long-Term Ecological Research project, to assess spatial and temporal dynamics of hydrologic connectivity between glaciers, streams, and lakes. Long-term records of stream discharge (Q), specific electrical conductance (EC), and water temperature (T) from 18 streams were analysed in order to quantify the magnitude, duration, and frequency of hydrologic connections over daily, annual, and inter-annual timescales. At a daily timescale, we observe predictable diurnal variations in Q, EC, and T. At an annual timescale, we observe longer streams to be more intermittent, warmer, and have higher median EC values, compared to shorter streams. Longer streams also behave chemostatically with respect to EC, whereas shorter streams are more strongly characterized by dilution. Inter-annually, we observe significant variability in annual runoff volumes, likely because of climatic variability over the 20 record years considered. Hydrologic connections at all timescales are vital to stream ecosystem structure and function. This synthesis of hydrologic connectivity in the MDVs provides a useful end-member template for assessing hydrologic connectivity in more structurally complex temperate watersheds. 

1 aWlostowski, Adam1 aGooseff, Michael, N.1 aMcKnight, Diane, M.1 aJaros, Chris1 aLyons, Berry uhttp://onlinelibrary.wiley.com/doi/10.1002/hyp.1081804082nas a2200157 4500008004100000245010000041210006900141260001200210490000700222520353000229100002903759700002503788700001803813700002103831856007203852 2016 eng d00aPhotoadaptation to the polar night by phytoplankton in a permanently ice-covered Antarctic lake0 aPhotoadaptation to the polar night by phytoplankton in a permane c05/20150 v613 a

Photosynthetic microorganisms are a primary source of new organic carbon production in polar ecosystems. Despite their importance, relatively little is known about how they adapt to the bimodal solar cycles that exist at high latitudes. To understand how phytoplankton adapt to the extreme seasonal change in photoperiod, we transplanted cultures of a well-studied laboratory model for photosynthetic cold adaptation, Chlamydomonas raudensis UWO241, back to the water column of Lake Bonney (McMurdo Dry Valleys, Antarctica) at the depth from which it was originally cultured. The organism was suspended at this depth in dialysis tubing to allow the microalga to respond to the in situ light, temperature and dissolved ions. We then integrated in situ biological and chemical measurements with environmental molecular analyses and compared the responses of transplanted C. raudensis cultures with the natural phytoplankton community over the 6-week transition from Antarctic summer (24-h daylight) to polar night (24-h darkness). As solar radiation declined, natural communities exhibited a cessation of inorganic carbon fixation which was accompanied by a downregulation of expression of genes encoding for essential carbon fixation and photochemistry proteins. Transplanted C. raudensis cultures matched natural community trends in the regulation of photochemistry and carbon fixation gene expression, and shifted photochemical function to a shade adapted state in response to the polar night transition. We present a conceptual model for seasonal shifts in microbial community energy and carbon acquisition which integrates past cultivation-based studies in this model photopsychrophile with a body of recent work on adaptation of natural populations to polar night.

1 aMorgan-Kiss, Rachael, M.1 aLizotte, Michael, P.1 aKong, Weidong1 aPriscu, John, C. uhttps://aslopubs.onlinelibrary.wiley.com/doi/full/10.1002/lno.1010700943nas a2200253 4500008004100000022001400041245008700055210006900142260001600211300001400227490000700241100002200248700002100270700002600291700002500317700001200342700002900354700002100383700002100404700002800425700002700453700002200480856018700502 2016 eng d a0006-356800aResponses of Antarctic Marine and Freshwater Ecosystems to Changing Ice Conditions0 aResponses of Antarctic Marine and Freshwater Ecosystems to Chang cJan-10-2016 a864 - 8790 v661 aObryk, Maciek, K.1 aDoran, Peter, T.1 aFriedlaender, Ari, S.1 aGooseff, Michael, N.1 aLi, Wei1 aMorgan-Kiss, Rachael, M.1 aPriscu, John, C.1 aSchofield, Oscar1 aStammerjohn, Sharon, E.1 aSteinberg, Deborah, K.1 aDucklow, Hugh, W. uhttps://academic.oup.com/bioscience/article-lookup/doi/10.1093/biosci/biw109https://academic.oup.com/bioscience/article/66/10/864/2415532/Responses-of-Antarctic-Marine-and-Freshwater01836nas a2200193 4500008004100000245013000041210006900171260001200240300001600252490000700268520116600275100002501441700002401466700002001490700002401510700002401534700001701558856006701575 2016 eng d00aStream biogeochemical and suspended sediment responses to permafrost degradation in stream banks in Taylor Valley, Antarctica0 aStream biogeochemical and suspended sediment responses to permaf c03/2016 a1723 - 17320 v133 a

 Stream channels in the McMurdo Dry Valleys are characteristically wide, incised, and stable. At typical flows, streams occupy a fraction of the oversized channels, providing habitat for algal mats. In January 2012, we discovered substantial channel erosion and subsurface thermomechanical erosion undercutting banks of the Crescent Stream. We sampled stream water along the impacted reach and compared concentrations of solutes to the long-term data from this stream ( ∼  20 years of monitoring). Thermokarst-impacted stream water demonstrated higher electrical conductivity, and concentrations of chloride, sulfate, sodium, and nitrate than the long-term medians. These results suggest that this mode of lateral permafrost degradation may substantially impact stream solute loads and potentially fertilize stream and lake ecosystems. The potential for sediment to scour or bury stream algal mats is yet to be determined, though it may offset impacts of associated increased nutrient loads to streams.

1 aGooseff, Michael, N.1 aVan Horn, David, J.1 aSudman, Zachary1 aMcKnight, Diane, M.1 aWelch, Kathleen, A.1 aLyons, Berry uhttp://www.biogeosciences.net/13/1723/2016/bg-13-1723-2016.pdf04687nas a2200181 4500008004100000022001400041245015900055210006900214260001200283300001600295490000700311520405500318100001204373700001804385700002904403700001804432856005504450 2016 eng d a0099-224000aUltrastructural and Single-Cell-Level Characterization Reveals Metabolic Versatility in a Microbial Eukaryote Community from an Ice-Covered Antarctic Lake0 aUltrastructural and SingleCellLevel Characterization Reveals Met c06/2016 a3659 - 36700 v823 a

The McMurdo Dry Valleys (MCM) of southern Victoria Land, Antarctica, harbor numerous ice-covered bodies of water that provide year-round liquid water oases for isolated food webs dominated by the microbial loop. Single-cell microbial eukaryotes (protists) occupy major trophic positions within this truncated food web, ranging from primary producers (e.g., chlorophytes, haptophytes, and cryptophytes) to tertiary predators (e.g., ciliates, dinoflagellates, and choanoflagellates). To advance the understanding of MCM protist ecology and the roles of MCM protists in nutrient and energy cycling, we investigated potential metabolic strategies and microbial interactions of key MCM protists isolated from a well-described lake (Lake Bonney). Fluorescence-activated cell sorting (FACS) of enrichment cultures, combined with single amplified genome/amplicon sequencing and fluorescence microscopy, revealed that MCM protists possess diverse potential metabolic capabilities and interactions. Two metabolically distinct bacterial clades (Flavobacteria and Methylobacteriaceae) were independently associated with two key MCM lake microalgae (Isochrysis and Chlamydomonas, respectively). We also report on the discovery of two heterotrophic nanoflagellates belonging to the Stramenopila supergroup, one of which lives as a parasite ofChlamydomonas, a dominate primary producer in the shallow, nutrient-poor layers of the lake.

IMPORTANCE Single-cell eukaryotes called protists play critical roles in the cycling of organic matter in aquatic environments. In the ice-covered lakes of Antarctica, protists play key roles in the aquatic food web, providing the majority of organic carbon to the rest of the food web (photosynthetic protists) and acting as the major consumers at the top of the food web (predatory protists). In this study, we utilized a combination of techniques (microscopy, cell sorting, and genomic analysis) to describe the trophic abilities of Antarctic lake protists and their potential interactions with other microbes. Our work reveals that Antarctic lake protists rely on metabolic versatility for their energy and nutrient requirements in this unique and isolated environment.

1 aLi, Wei1 aPodar, Mircea1 aMorgan-Kiss, Rachael, M.1 aKelly, R., M. uhttp://aem.asm.org/lookup/doi/10.1128/AEM.00478-1603321nas a2200205 4500008004100000022001400041245008600055210006900141260001200210300001600222490000700238520262100245100001702866700002302883700002402906700002502930700001502955700002402970856012102994 2015 eng d a0091-761300aAntarctic streams as a potential source of iron for the Southern Ocean: Figure 1.0 aAntarctic streams as a potential source of iron for the Southern c11/2016 a1003 - 10060 v433 a

Due to iron’s role in oceanic primary production, there has been great interest in quantifying the importance of Fe in regions where concentrations are very low and macronutrients, nitrate and phosphate, are available. Measurements of filterable (i.e., <0.4 μm) Fe concentrations in streams from Taylor Valley, McMurdo Dry Valleys, Antarctica, suggest that coastal-zone stream Fe input to the Southern Ocean could potentially play an important role in primary production in nearshore regions. Filterable Fe (fFe) data from streams in the McMurdo Dry Valleys were used to represent glacier meltwater that flows through ice-free landscape with the potential of transporting Fe to the Antarctic coastal zone. Estimates of potential fFe flux to the Antarctic Peninsula region using our mean fFe concentration of 10.6 µg L–1 combined with an estimate of ice-free area for the Antarctic Peninsula result in an fFe flux of 1.2 × 107 g yr–1. Although small compared to iceberg and aeolian Fe fluxes, future stream input to the Southern Ocean could increase due to glacier retreat and 

1 aLyons, Berry1 aDailey, Kelsey, R.1 aWelch, Kathleen, A.1 aDeuerling, Kelly, M.1 aWelch, Sue1 aMcKnight, Diane, M. uhttp://geology.gsapubs.org/lookup/doi/10.1130/G36989.1http://geology.geoscienceworld.org/lookup/doi/10.1130/G36989.103075nas a2200157 4500008004100000024003700041245014500078210006900223260003500292300000700327490002500334520248000359100002402839700001702863856003702880 2015 eng d ahttp://hdl.handle.net/1811/6888700aChemical Weathering and Mineralogy of McMurdo Dry Valley Streams: Examining the Controls of Current and Future Ephemeral Stream Geochemistry0 aChemical Weathering and Mineralogy of McMurdo Dry Valley Streams aOhio State Universityc05/2015 a380 vUndergraduate Theses3 a

The McMurdo Dry Valleys form the largest ice-free region in Antarctica and are the coldest, driest deserts in the world. But, for approximately 6-12 weeks per year in the austral summer, continuous sunlight and near-freezing temperatures create meltwater streams that descend from the surrounding alpine glaciers. These ephemeral streams are a distinctive feature in the barren dry valley landscape and are important sources of nutrients and solutes from the weathering of streambed and hyporheic zone materials. This setting has been a US National Science Foundation funded Long-Term Ecological Research (LTER) project since 1993. A major goal of the McMurdo LTER is to understand how liquid water, the primary limiting condition for life in Antarctica, is affected by climate variability. The McMurdo Dry Valleys are extremely climate-sensitive and even seemingly small variations in temperature can have a drastic effect on hydrological activity. The McMurdo LTER program has been successful in collecting and analyzing a large amount of stream data pertaining to weathering products but, a more comprehensive analysis and interpretation of the data have yet to be undertaken. Assessment of current and future stream geochemistry is critical to predict the impact of increased water flow due to glacier melt and increasing temperature which could greatly influence the ecological function and biologic diversity in the McMurdo Dry Valleys. Surface sediments were collected at multiple locations from ephemeral streams and analyzed using a scanning electron microscope and x-ray diffraction to determine sediment mineralogy and evidence of chemical weathering. Geochemical reactions were modeled using previously collected stream water data and the USGS PHREEQC software for the speciation calculations and the assessment of the solubility controlling solid phases. Chemical weathering was apparent through visible mineral alteration and the formation of secondary weathering products. Modeling results indicate that stream geochemistry will not significantly be affected by increased water temperature in the future. These results suggest stream geochemistry and chemical weathering may instead be controlled primarily through hydrologic exchange in the hyporheic zone.

1 aScheuermann, Jordan1 aLyons, Berry uhttp://hdl.handle.net/1811/6888708594nas a2200241 4500008004100000022001300041245020300054210006900257260001200326300001400338490000800352520755800360100001907918700002407937700002007961700002407981700002308005700002308028700001708051700002708068700002708095856023008122 2015 eng d a0009254100aComparison of arsenic and molybdenum geochemistry in meromictic lakes of the McMurdo Dry Valleys, Antarctica: Implications for oxyanion-forming trace element behavior in permanently stratified lakes0 aComparison of arsenic and molybdenum geochemistry in meromictic  c05/2015 a110 - 1250 v4043 a

Water samples were collected for arsenic (As) and molybdenum (Mo) analysis from different depths in Lakes Hoare and Fryxell, both of which are located in the Taylor Valley within the McMurdo Dry Valleys of Antarctica. Sampling depths within each lake were chosen to capture variations in As and Mo concentrations and As speciation in the oxic mixolimnia and anoxic monimolimnia of these meromictic lakes. Arsenic concentrations ranged from 0.67 nmol kg− 1 to 3.54 nmol kg− 1 in Lake Hoare and from 1.69 nmol kg− 1 to 17.5 nmol kg− 1 in Lake Fryxell. Molybdenum concentrations varied between 5.05 nmol kg− 1 and 43 nmol kg− 1 in Lake Hoare, and between 3.52 nmol kg− 1 and 25.5 nmol kg− 1 in Lake Fryxell. Concentrations of As and Mo generally increased with depth in the mixolimnion of each lake, consistent with uptake near the ice–water interface by organic particles and/or Fe/Mn oxides/oxyhydroxides, followed by gravitational settling and regeneration/remineralization at depth in the vicinity of the redoxcline. Arsenic concentrations either remained constant (Hoare) or increased with depth (Fryxell) in the anoxic monimolimnia, whereas Mo exhibited dramatic decreases in concentrations across the redoxcline in both lakes. Geochemical modeling predicts that As and Mo occur as thioanions in the anoxic bottom waters of Lakes Hoare and Fryxell, and further that the contrasting behavior of both trace elements reflects the respective reactivity of their thioanions towards Fe-sulfide minerals such as mackinawite (FeS) and/or pyrite (FeS2). More specifically, the geochemical model suggests that Fe-sulfide mineral precipitation in the anoxic monimolimnia of both lakes regulates dissolved sulfide concentrations at levels that are too low for As-sulfide minerals (e.g., orpiment, realgar) to precipitate, whereas mackinawite and/or pyrite react(s) with particle reactive thiomolybdate anions, possibly forming an Fe–Mo–S mineral that precipitates and, hence, leads to Mo removal from solution.

1 aYang, Ningfang1 aWelch, Kathleen, A.1 aMohajerin, Jade1 aTelfeyan, Katherine1 aChevis, Darren, A.1 aGrimm, Deborah, A.1 aLyons, Berry1 aWhite, Christopher, D.1 aJohannesson, Karen, H. uhttp://linkinghub.elsevier.com/retrieve/pii/S0009254115001874http://api.elsevier.com/content/article/PII:S0009254115001874?httpAccept=text/xmlhttp://api.elsevier.com/content/article/PII:S0009254115001874?httpAccept=text/plain01522nas a2200181 4500008004100000022001400041245007100055210006900126260001200195300001400207490000700221520096100228100002101189700002401210700001701234700002401251856006501275 2015 eng d a0954-102000aExperimental formation of pore fluids in McMurdo Dry Valleys soils0 aExperimental formation of pore fluids in McMurdo Dry Valleys soi c04/2015 a163 - 1710 v273 a

The aim of the study was to determine if soil salt deliquescence and brine hydration can occur under laboratory conditions using natural McMurdo Dry Valleys soils. The experiment was a laboratory analogue for the formation of isolated patches of hypersaline, damp soil, referred to as ‘wet patches’. Soils were oven dried and then hydrated in one of two humidity chambers: one at 100% relative humidity and the second at 75% relative humidity. Soil hydration is highly variable, and over the course of 20 days of hydration, ranged from increases in water content by mass from 0–16% for 122 soil samples from Taylor Valley. The rate and absolute amount of soil hydration correlates well with the soluble salt content of the soils but not with grain size distribution. This suggests that the formation of bulk pore waters in these soils is a consequence of salt deliquescence and hydration of the brine from atmospheric water vapour.

1 aLevy, Joseph, S.1 aFountain, Andrew, G1 aLyons, Berry1 aWelch, Kathleen, A. uhttp://www.journals.cambridge.org/abstract_S095410201400047902358nas a2200229 4500008004100000022001400041245011300055210006900168260001200237490000600249520163400255100002801889700001901917700001901936700002401955700001601979700001701995700001902012700002002031700002102051856005602072 2015 eng d a2150-892500aFostering ecological data sharing: collaborations in the International Long Term Ecological Research Network0 aFostering ecological data sharing collaborations in the Internat c10/20150 v63 a

The International Long Term Ecological Research (ILTER) Network was established in 1993 and is now composed of thirty-eight national networks representing a diversity of ecosystems around the globe. Data generated by the ILTER Network are valuable for scientists addressing broad spatial and temporal scale research questions, but only if these data can be easily discovered, accessed, and understood. Challenges to publishing ILTER data have included unequal distribution among networks of information management expertise, user-friendly tools, and resources. Language and translation have also been issues. Despite these significant obstacles, ILTER information managers have formed grassroots partnerships and collaborated to provide information management training, adopt a common metadata standard, develop information management tools useful throughout the network, and organize scientist/information manager workshops that encourage scientists to share and integrate data. Throughout this article, we share lessons learned from the successes of these grassroots international partnerships to inform others who wish to collaborate internationally on projects that depend on data sharing entailing similar management challenges.
 

1 aVanderbilt, Kristin, L.1 aLin, Chau-Chin1 aLu, Sheng-Shan1 aKassim, Abd, Rahman1 aHe, Honglin1 aGuo, Xuebing1 aSan Gil, Inigo1 aBlankman, David1 aPorter, John, H. uhttp://www.esajournals.org/doi/10.1890/ES14-00281.100932nas a2200265 4500008004100000022001400041245013400055210006900189260001200258300001400270490000800284100002300292700002800315700001600343700002000359700002500379700002200404700002100426700001700447700002300464700002200487700002400509700001600533856011700549 2015 eng d a0029-854900aGlobal environmental change and the nature of aboveground net primary productivity responses: insights from long-term experiments0 aGlobal environmental change and the nature of aboveground net pr c04/2015 a935 - 9470 v1771 aSmith, Melinda, D.1 aLa Pierre, Kimberly, J.1 aCollins, SL1 aKnapp, Alan, K.1 aGross, Katherine, L.1 aBarrett, John, E.1 aFrey, Serita, D.1 aGough, Laura1 aMiller, Robert, J.1 aMorris, James, T.1 aRustad, Lindsey, E.1 aYarie, John uhttp://link.springer.com/10.1007/s00442-015-3230-9http://link.springer.com/content/pdf/10.1007/s00442-015-3230-902538nas a2200205 4500008004100000245010400041210006900145260001200214300001200226490000700238520189000245100002202135700002102157700001902178700001302197700001602210700001702226700002402243856006502267 2015 eng d00a Long-Term Hydrologic Control of Microbial Mat Abundance in McMurdo Dry Valley Streams, Antarctica.0 aLongTerm Hydrologic Control of Microbial Mat Abundance in McMurd c03/2015 a310-3270 v183 a

Given alterations in global hydrologic regime, we examine the role of hydrology in regulating stream microbial mat abundance in the McMurdo Dry Valleys, Antarctica. Here, perennial mats persist as a desiccated crust until revived by summer streamflow, which varies inter-annually, and has increased since the 1990s. We predicted high flows to scour mats, and intra-seasonal drying to slow growth. Responses were hypothesized to differ based on mat location within streams, along with geomorphology, which may promote (high coverage) or discourage (low coverage) accrual. We compared hydrologic trends with the biomass of green and orange mats, which grow in the channel, and black mats growing at stream margins for 16 diverse stream transects over two decades. We found mat biomass collectively decreased during first decade coinciding with low flows, and increased following elevated discharges. Green mat biomass showed the greatest correlations with hydrology and was stimulated by discharge in high coverage transects, but negatively correlated in low coverage due to habitat scour. In contrast, orange mat biomass was negatively related to flow in high coverage transects, but positively correlated in low coverage because of side-channel expansion. Black mats were weakly correlated with all hydrologic variables regardless of coverage. Lastly, model selection indicated the best combination of predictive hydrologic variables for biomass differed between mat types, but also high and low coverage transects. These results demonstrate the importance of geomorphology and species composition to modeling primary production, and will be useful in predicting ecological responses of benthic habitats to altered hydrologic regimes.

1 aKohler, Tyler, J.1 aStanish, Lee, F.1 aCrisp, Stenven1 aKoch, J.1 aLiptzin, D.1 aBaeseman, J.1 aMcKnight, Diane, M. uhttp://link.springer.com/article/10.1007%2Fs10021-014-9829-606572nas a2200169 4500008004100000245008400041210006900125520601300194100001906207700002406226700001506250700001906265700001706284700002106301700002406322856005606346 2015 eng d00aPatterns and processes of salt efflorescences in the McMurdo region, Antarctica0 aPatterns and processes of salt efflorescences in the McMurdo reg3 a

Evaporite salts are abundant around the McMurdo region, Antarctica (~78°S) due to very low precipitation, low relative humidity, and limited overland flow. Hygroscopic salts in the McMurdo Dry Valleys (MDVs) are preferentially formed in locations where liquid water is present in the austral summer, including along ephemeral streams, ice-covered lake boundaries, or shallow groundwater tracks. In this study, we collected salts from the Miers, Garwood, and Taylor Valleys on the Antarctic continent, as well as around McMurdo Station on Ross Island in close proximity to water sources with the goal of understanding salt geochemistry in relationship to the hydrology of the area. Halite is ubiquitous; sodium is the major cation (ranging from 70%–90% of cations by meq kg−1 sediment) and chloride is the major anion (>50%) in nearly all samples. However, a wide variety of salt phases and morphologies are tentatively identified through scanning electron microscopy (SEM) and X-ray diffraction (XRD) work. We present new data that identifies trona (Na3(CO3)(HCO3)·2H2O), tentative gaylussite (Na2Ca(CO3)2·5H2O), and tentative glauberite (Na2Ca(SO4)2) in the MDV, of which the later one has not been documented previously. Our work allows for the evaluation of processes that influence brine evolution on a local scale, consequently informing assumptions underlying large-scale processes (such as paleoclimate) in the MDV. Hydrological modeling conducted in FREZCHEM and PHREEQC suggests that a model based on aerosol deposition alone in low elevations on the valley floor inadequately characterizes salt distributions found on the surfaces of the soil because it does not account for other hydrologic inputs/outputs. Implications for the salt distributions include their use as tracers for paleolake levels, geochemical tracers of ephemeral water tracks or “wet patches” in the soil, indicators of chemical weathering products, and potential delineators of ecological communities.

1 aBisson, K., M.1 aWelch, Kathleen, A.1 aWelch, Sue1 aSheets, J., M.1 aLyons, Berry1 aLevy, Joseph, S.1 aFountain, Andrew, G uhttp://aaarjournal.org/doi/abs/10.1657/AAAR0014-02400864nas a2200217 4500008004100000245020400041210006900245260001200314300001600326490000700342100002400349700001600373700002400389700002500413700001700438700001300455700001700468700002100485700002100506856011900527 2015 eng d00aPotential for real-time understanding of coupled hydrologic and biogeochemical processes in stream ecosystems: Future integration of telemetered data with process models for glacial meltwater streams0 aPotential for realtime understanding of coupled hydrologic and b c08/2015 a6725 - 67380 v511 aMcKnight, Diane, M.1 aCozzetto, K1 aCullis, James, D.S.1 aGooseff, Michael, N.1 aJaros, Chris1 aKoch, J.1 aLyons, Berry1 aNeupauer, R., M.1 aWlostowski, Adam uhttp://doi.wiley.com/10.1002/2015WR017618http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2F2015WR01761804591nas a2201033 4500008004100000022001400041245009100055210006900146260001600215300001100231490000700242520199300249100002002242700002202262700001802284700001602302700002002318700001502338700001802353700001502371700001802386700001702404700001602421700001402437700001402451700001702465700001802482700002102500700001602521700001102537700001502548700002002563700001902583700001602602700001802618700001602636700001402652700001602666700001502682700001602697700001602713700001602729700001802745700001602763700001602779700001302795700001802808700001202826700001402838700001402852700001402866700001602880700001402896700001402910700002002924700001102944700001702955700001502972700002502987700001603012700001703028700001703045700001503062700001703077700001403094700001403108700001703122700001803139700001603157700002403173700002303197700001603220700001503236700001603251700001803267700001803285700001803303700001803321700001503339700001803354700002003372700001603392700001503408700001803423700001703441700001303458700002103471856006503492 2015 eng d a0954-102000aA roadmap for Antarctic and Southern Ocean science for the next two decades and beyond0 aroadmap for Antarctic and Southern Ocean science for the next tw cJan-02-2015 a3 - 180 v273 a

Antarctic and Southern Ocean science is vital to understanding natural variability, the processes that govern global change and the role of humans in the Earth and climate system. The potential for new knowledge to be gained from future Antarctic science is substantial. Therefore, the international Antarctic community came together to ‘scan the horizon’ to identify the highest priority scientific questions that researchers should aspire to answer in the next two decades and beyond. Wide consultation was a fundamental principle for the development of a collective, international view of the most important future directions in Antarctic science. From the many possibilities, the horizon scan identified 80 key scientific questions through structured debate, discussion, revision and voting. Questions were clustered into seven topics: i) Antarctic atmosphere and global connections, ii) Southern Ocean and sea ice in a warming world, iii) ice sheet and sea level, iv) the dynamic Earth, v) life on the precipice, vi) near-Earth space and beyond, and vii) human presence in Antarctica. Answering the questions identified by the horizon scan will require innovative experimental designs, novel applications of technology, invention of next-generation field and laboratory approaches, and expanded observing systems and networks. Unbiased, non-contaminating procedures will be required to retrieve the requisite air, biota, sediment, rock, ice and water samples. Sustained year-round access to Antarctica and the Southern Ocean will be essential to increase winter-time measurements. Improved models are needed that represent Antarctica and the Southern Ocean in the Earth System, and provide predictions at spatial and temporal resolutions useful for decision making. A co-ordinated portfolio of cross-disciplinary science, based on new models of international collaboration, will be essential as no scientist, programme or nation can realize these aspirations alone

1 aKennicutt, M.C.1 aChown, Steven, L.1 aCassano, J.J.1 aLiggett, D.1 aPeck, Lloyd, S.1 aMassom, R.1 aRintoul, S.R.1 aStorey, J.1 aVaughan, D.G.1 aWilson, T.J.1 aAllison, I.1 aAyton, J.1 aBadhe, R.1 aBaeseman, J.1 aBarrett, P.J.1 aBell, Elanor, R.1 aBertler, N.1 aBo, S.1 aBrandt, A.1 aBromwich, David1 aCary, Craig, S1 aClark, M.S.1 aConvey, Peter1 aCosta, E.S.1 aCowan, D.1 aDeconto, R.1 aDunbar, R.1 aElfring, C.1 aEscutia, C.1 aFrancis, J.1 aFricker, H.A.1 aFukuchi, M.1 aGilbert, N.1 aGutt, J.1 aHavermans, C.1 aHik, D.1 aHosie, G.1 aJones, C.1 aKim, Y.D.1 aLe Maho, Y.1 aLee, S.H.1 aLeppe, M.1 aLeitchenkov, G.1 aLi, X.1 aLipenkov, V.1 aLochte, K.1 aLópez-Martínez, J.1 aüdecke, C.1 aLyons, Berry1 aMarenssi, S.1 aMiller, H.1 aMorozova, P.1 aNaish, T.1 aNayak, S.1 aRavindra, R.1 aRetamales, J.1 aRicci, C.A.1 aRogan-Finnemore, M.1 aRopert-Coudert, Y.1 aSamah, A.A.1 aSanson, L.1 aScambos, T.1 aSchloss, I.R.1 aShiraishi, K.1 aSiegert, M.J.1 aSimões, J.C.1 aStorey, B.1 aSparrow, M.D.1 aWall, Diana, H.1 aWalsh, J.C.1 aWilson, G.1 aWinther, J.G.1 aXavier, J.C.1 aYang, H.1 aSutherland, W.J. uhttp://www.journals.cambridge.org/abstract_S095410201400067401763nas a2200157 4500008004100000245010800041210006900149260001200218300001200230490000700242520123700249100002101486700002501507700002501532856004801557 2015 eng d00aSpatiotemporal Dynamics of Wetted Soils across a Polar Desert Landscape, McMurdo Dry Valleys Antarctica0 aSpatiotemporal Dynamics of Wetted Soils across a Polar Desert La c04/2015 a197-2090 v273 aLiquid water is scarce across the landscape of the McMurdo Dry Valleys (MDV), Antarctica, a 3800 km2 ice-free region, and is chiefly associated with soils that are adjacent to streams and lakes (i.e. wetted margins) during the annual thaw season. However, isolated wetted soils have been observed at locations distal from water bodies. The source of water for the isolated patches of wet soil is potentially generated by a combination of infiltration from melting snowpacks, melting of pore ice at the ice table, and melting of buried segregation ice formed during winter freezing. High resolution remote sensing data gathered several times per summer in the MDV region were used to determine the spatial and temporal distribution of wet soils. The spatial consistency with which the wet soils occurred was assessed for the 2009–10 to 2011–12 summers. The remote sensing analyses reveal that cumulative area and number of wet soil patches varies among summers. The 2010–11 summer provided the most wetted soil area (10.21 km2) and 2009–10 covered the least (5.38 km2). These data suggest that wet soils are a significant component of the MDV cold desert land system and may become more prevalent as regional climate changes.1 aLangford, Z., L.1 aGooseff, Michael, N.1 aLampkin, Derrick, J. uhttp://dx.doi.org/10.1017/S095410201400060104850nas a2200217 4500008004100000022001300041245007600054210006900130260001200199300001400211490000800225520403500233100001704268700001704285700002204302700001904324700001404343700002404357700002104381856023004402 2014 eng d a0009254100aBoron isotopic geochemistry of the McMurdo Dry Valley lakes, Antarctica0 aBoron isotopic geochemistry of the McMurdo Dry Valley lakes Anta c10/2014 a152 - 1640 v3863 a

 

The geochemistry of boron was investigated in the ice-covered lakes and glacier meltwater streams within Taylor and Wright Valley of the McMurdo Dry Valleys (MCM), Antarctica, in order to achieve a greater understanding of the source of boron to these aquatic systems and how in-lake processes control boron concentration. Selected lake depths (surface and bottom water) and streams were analyzed for boron geochemistry. Boron stable isotope values in these waters span the range of + 12.3‰ to + 51.4‰, which corresponds to the variations from glacier meltwater streams to the hypolimnion of a highly evaporated hypersaline lake. The data demonstrate that the major sources of B to the aquatic system are via terrestrial chemical weathering of aluminosilicates within the stream channels, and a marine source, either currently being introduced by marine-derived aerosols or in the form of ancient seawater. Lakes Fryxell, Hoare, and upper waters of Lake Joyce, which experience more terrestrial influence of aluminosilicate chemical weathering via glacial meltwater streams, display a mixture of these two major sources, while the source of B in the bottom waters of Lake Joyce appears to be primarily of marine origin. Lakes Bonney and Vanda and the Blood Falls brine have a marine-like source whose δ11B values have become more positive by mineral precipitation and/or adsorption. Don Juan Pond displays a terrestrial aluminosilicate influence of a marine-like source. These hypersaline lake waters from Antarctica are similar in δ11B to other hypersaline lake waters globally, suggesting that similar processes control their B geochemistry.

 

 

1 aLeslie, D.L.1 aLyons, Berry1 aWarner, Nathaniel1 aVengosh, Avner1 aOlesik, J1 aWelch, Kathleen, A.1 aDeuerling, Kelly uhttp://linkinghub.elsevier.com/retrieve/pii/S000925411400391Xhttp://api.elsevier.com/content/article/PII:S000925411400391X?httpAccept=text/xmlhttp://api.elsevier.com/content/article/PII:S000925411400391X?httpAccept=text/plain02515nas a2200169 4500008004100000022001400041245016900055210006900224260001600293300001400309490000700323520188900330100002102219700002302240700001702263856006502280 2014 eng d a0954-102000aThe effects of high meltwater on the limnology of Lake Fryxell and Lake Hoare, Taylor Valley, Antarctica, as shown by dissolved gas, tritium and chlorofluorocarbons0 aeffects of high meltwater on the limnology of Lake Fryxell and L cJan-08-2014 a331 - 3400 v263 a

Small changes in the availability of liquid water can have profound effects on the water levels, aqueous chemistry and biogeochemical dynamics of the closed-basin, perennially ice-covered lakes of the McMurdo Dry Valleys, Antarctica. We have compiled the published and unpublished data on dissolved gas, tritium and chlorofluorocarbons (CFCs) for Lake Fryxell and Lake Hoare to determine the effects of a high meltwater year (2001–02 summer) on the lakes. The dissolved gas, tritium and CFC data indicate that the pulse of freshwater that flowed onto the surfaces of the lakes did not mix extensively with the upper water column. At the bottom of Lake Hoare, the measurable CFC and lower dissolved gas values suggest that the recent meltwater may have mixed with bottom waters. The probable mechanism for this transportation is weak density currents with c. 0.1–1.5% surface water being transported downwards in Lake Hoare. This deep water input, while not constant, may have a significant effect on the chemistry of the bottom waters in Lake Hoare over time. In Lake Fryxell, the tritium and CFC data indicate that the recent meltwater did not significantly affect the bottom water chemistry; therefore, weak density currents may not be present in Lake Fryxell.

1 aDowling, Carolyn1 aPoreda, Robert, J.1 aLyons, Berry uhttp://www.journals.cambridge.org/abstract_S095410201300062X03450nas a2200169 4500008004100000245009600041210006900137260004500206300000800251490001800259520283100277100003003108700001703138700002003155700001803175856008703193 2014 eng d00aElemental Cycling in a Flow-Through Lake in the McMurdo Dry Valleys, Antarctica: Lake Miers0 aElemental Cycling in a FlowThrough Lake in the McMurdo Dry Valle aColumbusbOhio State Universityc06/2014 a1220 vMaster Thesis3 a

The ice-free area in Antarctica known as the McMurdo Dry Valleys has been monitored biologically, meteorologically, hydrologically, and geochemically continuously since the onset of the MCM-LTER in 1993. This area contains a functioning ecosystem living in an extremely delicate environment. Only a few degrees of difference in air temperature can effect on the hydrologic system, making it a prime area to study ongoing climate change. The unique hydrology of Lake Miers, i.e. its flowthrough nature, makes it an ideal candidate to study the mass balance of a McMurdo Dry Valley lake because both input and output concentrations can be analyzed. This study seeks to understand the physical and geochemical hydrology of Lake Miers relative to other MCMDV lakes. Samples were collected from the two inflowing streams, the outflowing stream, and the lake itself at 11 depths to analyze a suite of major cations (Li+ , Na+ , K+ , Mg+ , Ca2+), major anions (Cl- , Br- , F- , SO4 2- , ΣCO2), nutrients (NO2 - , NO3 - , NH4 + , PO4 3- , Si), trace elements (Mo, Rb, Sr, Ba, U, V, Cu, As), water isotopes (δD, δ 18O), and dissolved organic carbon (DOC). The lake acts as a sink for all constituents analyzed, but by amounts varying from ~10% (DOC, NH4 + , and NO2 - ) to PO4 3- at nearly 100%, indicating this lake may be P-limited. Cl- , a typically conservative element, was only 79% retained, which could be due to the late season sample collection, hyperheic zone influences, or other factors. The hyperheic zone’s role in lake and stream iii geochemistry was analyzed with a 24-hour sampling event. The positive relationships between stream flow and solute concentrations indicate that the delta in Miers Valley plays a role in controlling stream geochemistry and future work could help to explain this relationship. Lake depth profiles of trace elements U, V, Cu, and As decrease relative to Cl in the deepest part of the lake, while non-reducing trace elements show increases with depth. SO4 2- and dissolved O2 lake depth profiles decrease from 53 μM and 22.3 mg/L to 18 μM and 1.8 mg/L, respectively, at depth, indicating that the lake bottom is under reducing and near anoxic conditions. Lake depth profiles show that, while the “biological pump” may be a factor controlling lake chemistry, it is masked by the stronger signal of diffusion from the lake bottom sediments and requires future work to understand fully. The “age” of Lake Miers was calculated with a diffusion model to be 84 years, which agrees with other estimates of 100-300 years. The diffusion of solutes from the lake bottom and the redox conditions at depth are two major processes controlling the geochemistry of Lake Miers, and future work can help determine their extent and relationship with other processes.

1 aFair, Alexandria, Corinne1 aLyons, Berry1 aCarey, Anne, E.1 aChin, Yu-Ping uhttps://etd.ohiolink.edu/!etd.send_file?accession=osu1413291502&disposition=inline00633nas a2200193 4500008004100000245011600041210006900157260001200226300001400238490000700252100002200259700001800281700002000299700001400319700002600333700001600359700002100375856004300396 2014 eng d00aGlobal-scale patterns of assemblage structure of soil nematodes in relation to climate and ecosystem properties0 aGlobalscale patterns of assemblage structure of soil nematodes i c01/2014 a968 - 9780 v231 aNielsen, Uffe, N.1 aAyres, Edward1 aWall, Diana, H.1 aLi, Grace1 aBardgett, Richard, D.1 aWu, Tiehang1 aGarey, James, R. uhttp://doi.wiley.com/10.1111/geb.1217701695nas a2200181 4500008004100000022001400041245013500055210006900190260001200259300001400271490000700285520107500292100002101367700001601388700002401404700002001428856006501448 2014 eng d a0954-102000aHyperspectral measurements of wet, dry and saline soils from the McMurdo Dry Valleys: soil moisture properties from remote sensing0 aHyperspectral measurements of wet dry and saline soils from the  c10/2014 a565 - 5720 v263 a

Soil moisture is a spatially heterogeneous quantity in the McMurdo Dry Valleys of Antarctica that exerts a large influence on the biological community and on the thermal state of Dry Valleys permafrost. The goal of this project was to determine whether hyperspectral remote sensing techniques could be used to determine soil moisture conditions in the Dry Valleys. We measured the spectral reflectance factors of wetted soil samples from the Dry Valleys under natural light conditions and related diagnostic spectral features to surface layer soil moisture content. Diagnostic water absorption features in the spectra at 1.4 µm and 1.9 µm were present in all samples, including samples doped with high concentrations of chloride salts. The depth of the 1.4 µm absorption is shown to increase linearly with increasing gravimetric water content. These results suggest that airborne hyperspectral imaging of the Dry Valleys could generate soil moisture maps of this environment over large spatial areas using non-invasive remote-sensing techniques.

1 aLevy, Joseph, S.1 aNolin, Anne1 aFountain, Andrew, G1 aHead, James, W. uhttp://www.journals.cambridge.org/abstract_S095410201300097702542nas a2200181 4500008004100000022001300041245006800054210006300122260001200185300001200197490000800209520181900217100002402036700002102060700002502081700002402106856023002130 2014 eng d a0169555X00aThe McMurdo Dry Valleys: A landscape on the threshold of change0 aMcMurdo Dry Valleys A landscape on the threshold of change c11/2014 a25 - 350 v2253 a

Field observations of coastal and lowland regions in the McMurdo Dry Valleys suggest they are on the threshold of rapid topographic change, in contrast to the high elevation upland landscape that represents some of the lowest rates of surface change on Earth. A number of landscapes have undergone dramatic and unprecedented landscape changes over the past decade including, the Wright Lower Glacier (Wright Valley) — ablated several tens of meters, the Garwood River (Garwood Valley) has incised > 3 m into massive ice permafrost, smaller streams in Taylor Valley (Crescent, Lawson, and Lost Seal Streams) have experienced extensive down-cutting and/or bank undercutting, and Canada Glacier (Taylor Valley) has formed sheer, > 4 meter deep canyons. The commonality between all these landscape changes appears to be sediment on ice acting as a catalyst for melting, including ice-cement permafrost thaw. We attribute these changes to increasing solar radiation over the past decade despite no significant trend in summer air temperature. To infer possible future landscape changes in the McMurdo Dry Valleys, due to anticipated climate warming, we map ‘at risk’ landscapes defined as those with buried massive ice in relative warm regions of the valleys. Results show that large regions of the valley bottoms are ‘at risk’. Changes in surface topography will trigger important responses in hydrology, geochemistry, and biological community structure and function.

1 aFountain, Andrew, G1 aLevy, Joseph, S.1 aGooseff, Michael, N.1 aVan Horn, David, J. uhttp://linkinghub.elsevier.com/retrieve/pii/S0169555X14001780http://api.elsevier.com/content/article/PII:S0169555X14001780?httpAccept=text/xmlhttp://api.elsevier.com/content/article/PII:S0169555X14001780?httpAccept=text/plain01831nas a2200157 4500008004100000245009400041210006900135260001200204300001200216490000700228520126700235100001501502700002401517700001401541856011801555 2014 eng d00aNear-Surface Internal Melting - a Substantial Mass Loss on Antarctic Dry Valley Glaciers.0 aNearSurface Internal Melting a Substantial Mass Loss on Antarcti c04/2014 a361-3740 v603 aThe McMurdo Dry Valleys, southern Victoria Land, East Antarctica, are a polar desert, and melt from glacial ice is the primary source of water to streams, lakes and associated ecosystems. Previous work found that to adequately model glacier ablation and subsurface ice temperatures with a surface energy-balance model required including the transmission of solar radiation into the ice. Here we investigate the contribution of subsurface melt to the mass balance of (and runoff from) Dry Valley glaciers by including a drainage process in the model and applying the model to three glacier sites using 13years of hourly meteorological data. Model results for the smooth glacier surfaces common to many glaciers in the Dry Valleys showed that sublimation was typically the largest component of surface lowering, with rare episodes of surface melting, consistent with anecdotal field observations. Results also showed extensive internal melting 5-15 cm below the ice surface, the drainage of which accounted for 50% of summer ablation. This is consistent with field observations of subsurface streams and formation of a weathering crust. We identify an annual cycle of weathering crust formation in summer and its removal during the 10 months of winter sublimation.1 aHoffman, M1 aFountain, Andrew, G1 aListon, G uhttps://mcm.lternet.edu/content/near-surface-internal-melting-substantial-mass-loss-antarctic-dry-valley-glaciers00468nas a2200145 4500008004100000245005400041210005400095260001200149300001400161490000700175100002100182700002800203700001900231856007200250 2014 eng d00aPolar and alpine microbiology in a changing world0 aPolar and alpine microbiology in a changing world c08/2014 a209 - 2100 v891 aPriscu, John, C.1 aLaybourn-Parry, Johanna1 aHäggblom, Max uhttp://onlinelibrary.wiley.com/doi/10.1111/1574-6941.12371/abstract00623nas a2200169 4500008004100000245009600041210006900137260001200206300001200218490000700230100002100237700001800258700002100276700002200297700001700319856011700336 2014 eng d00aRadiocarbon abundance and reservoir effects in lakes of the McMurdo Dry Valleys, Antarctica0 aRadiocarbon abundance and reservoir effects in lakes of the McMu c05/2014 a811-8260 v591 aDoran, Peter, T.1 aKenig, Fabien1 aKnoepfle, Lawson1 aMikucki, Jill, A.1 aLyons, Berry uhttps://mcm.lternet.edu/content/radiocarbon-abundance-and-reservoir-effects-lakes-mcmurdo-dry-valleys-antarctica03560nas a2200397 4500008004100000022001400041245005200055210004800107260001200155300001400167490000700181520243500188100001802623700002202641700001902663700002502682700001902707700002002726700002202746700002102768700002402789700002102813700002302834700002702857700002302884700002802907700001702935700001902952700002202971700002002993700002103013700002503034700002603059700002003085856005703105 2014 eng d a0012-961500aThe spatial structure of Antarctic biodiversity0 aspatial structure of Antarctic biodiversity c05/2014 a203 - 2440 v843 a

Patterns of environmental spatial structure lie at the heart of the most fundamental and familiar patterns of diversity on Earth. Antarctica contains some of the strongest environmental gradients on the planet and therefore provides an ideal study ground to test hypotheses on the relevance of environmental variability for biodiversity. To answer the pivotal question, “How does spatial variation in physical and biological environmental properties across the Antarctic drive biodiversity?” we have synthesized current knowledge on environmental variability across terrestrial, freshwater, and marine Antarctic biomes and related this to the observed biotic patterns. The most important physical driver of Antarctic terrestrial communities is the availability of liquid water, itself driven by solar irradiance intensity. Patterns of biota distribution are further strongly influenced by the historical development of any given location or region, and by geographical barriers. In freshwater ecosystems, free water is also crucial, with further important influences from salinity, nutrient availability, oxygenation, and characteristics of ice cover and extent. In the marine biome there does not appear to be one major driving force, with the exception of the oceanographic boundary of the Polar Front. At smaller spatial scales, ice cover, ice scour, and salinity gradients are clearly important determinants of diversity at habitat and community level. Stochastic and extreme events remain an important driving force in all environments, particularly in the context of local extinction and colonization or recolonization, as well as that of temporal environmental variability. Our synthesis demonstrates that the Antarctic continent and surrounding oceans provide an ideal study ground to develop new biogeographical models, including life history and physiological traits, and to address questions regarding biological responses to environmental variability and change.

 

1 aConvey, Peter1 aChown, Steven, L.1 aClarke, Andrew1 aBarnes, David, K. A.1 aBokhorst, Stef1 aCummings, Vonda1 aDucklow, Hugh, W.1 aFrati, Francesco1 aGreen, T., G. Allan1 aGordon, Shulamit1 aGriffiths, Huw, J.1 aHoward-Williams, Clive1 aHuiskes, Ad, H. L.1 aLaybourn-Parry, Johanna1 aLyons, Berry1 aMcMinn, Andrew1 aMorley, Simon, A.1 aPeck, Lloyd, S.1 aQuesada, Antonio1 aRobinson, Sharon, A.1 aSchiaparelli, Stefano1 aWall, Diana, H. uhttp://www.esajournals.org/doi/abs/10.1890/12-2216.100634nas a2200181 4500008004100000245007700041210006900118260001200187490000600199100002100205700002400226700002300250700002000273700001900293700002400312700002000336856009600356 2013 eng d00aAccelerated thermokarst formation in the McMurdo Dry Valleys, Antarctica0 aAccelerated thermokarst formation in the McMurdo Dry Valleys Ant c07/20130 v31 aLevy, Joseph, S.1 aFountain, Andrew, G1 aDickson, James, L.1 aHead, James, W.1 aOkal, Marianne1 aMarchant, David, R.1 aWatters, Jaclyn uhttp://www.nature.com/srep/2013/130724/srep02269/full/srep02269.html?WT.ec_id=SREP-2013073003970nas a2200217 4500008004100000245011000041210007200151260004000223490001000263520322300273653001503496653001903511653001903530653002403549653003003573653003703603653001603640100001703656700001703673856006203690 2013 eng d00aThe application of stable isotopes, δ11B, δ18O, and δD, in geochemical and hydrological investigations0 aapplication of stable isotopes δ11B δ18O and δD in geochemical a aColumbus, OHbOhio State University0 vPh.D.3 a

My dissertation research utilizes stable isotopes as tracers of water and solute sources to study specific geochemical (solute origin) and hydrological (glacier meltwater source across a season comparing water contributions from hyporheic zone and/or glacier melt and residence time of precipitation within a managed water supply) problems within McMurdo Dry Valleys (MCM), Antarctica, and Central Ohio, USA. In Chapter II, δ11B isotopic and dissolved B measurements are used to infer the origin of B within MCM aquatic system. Boron stable isotopic values span the range of +12.3‰ to +51.4‰, varying from glacier meltwater streams to the hypolimnion of a highly evaporated hypersaline lake. These data demonstrate that the major sources of B are chemical weathering of alumniosilicates within the stream channels, and a marine source, either currently introduced by marine-derived aerosols or from ancient seawater. In-lake processes create a more positive δ11B through adsorption or mineral precipitation. The glacier meltwater streams, Lakes Fryxell, Hoare, and upper waters of Lake Joyce display a mixture of these two sources, with Lake Joyce bottom waters primarily of marine origin. Lakes Bonney and Vanda and Blood Falls brine are interpreted as having a marine-like source changed by in-lake processes to result in a more positive δ11B, while Don Juan Pond displays a more terrestrial influence. In Chapter III, δ18O and δD are used to trace water source variation via hyporheic zone or glacier melt within two MCM streams over an entire melt season. The isotopic variation of these streams was more negative at the beginning of the season and more positive later. D-excess measurements were used to infer mixing between hyporheic storage and glacier meltwater. It was supported that Von Guerard Stream has a large, widespread hyporheic zone that changes with time and discharge amounts. The chemistry of Andersen Creek also displayed hyporheic zone influence at certain times of the year. This work adds important new information on the role of hyperheic zone-stream interactions, and supports the short term, more physically based, descriptions of hyporheic dynamics explained in the past decade. Chapter IV describes water flow and travel time within a human managed watershed-reservoir system by measuring the δ18O and δD of the precipitation source to the reservoirs and finally to the distribution system, the tap. Generally, the tap waters experienced little lag time in the managed system, having a residence time of about two months. Tap and reservoir waters preserved the precipitation signal with the reservoir morphology acting as an important control. These water supply reservoirs functioned more like a river system with a faster throughput of water and larger variations in chemical parameters. Other water supply reservoirs have a greater capacity with a larger amount of water supply usage through a more lacustrine environment, which displays more constant solute concentrations and longer flow-through times. This work provides a basic understanding of a regional water supply system in central Ohio, reservoir isotopic dynamics, and Ohio precipitation sources.

10aAntarctica10aboron isotopes10ahyporheic zone10aMcMurdo Dry Valleys10aOhio precipitation source10aoxygen-18 and deuterium isotopes10asaline lake1 aLeslie, D.L.1 aLyons, Berry u http://rave.ohiolink.edu/etdc/view?acc_num=osu138600003702257nas a2200133 4500008004100000245011700041210006900158260004000227490000900267520175200276100002102028700002502049856004902074 2013 eng d00aAre the Dry Valleys getting wetter? A preliminary assessment of wetness across the McMurdo Dry Valleys landscape0 aAre the Dry Valleys getting wetter A preliminary assessment of w bPennsylvania State Universityc20130 vM.S.3 a

Liquid water is scarce across the landscape of the McMurdo Dry Valleys (MDV), Antarctica and is associated with soils that are adjacent to streams and lakes, during the annual thaw season. However, seeps, water tracks, and wet patches have been observed at several other locations as well. The source of water for these is likely generated by a combination of infiltration from melting snowpacks, melting of pore ice at the ice table beneath the water tracks, and melting of buried segregation ice formed during winter freezing. We are using high resolution (<1m pixel) remote sensing data gathered several times per week in the MDV region to determine the spatial and temporal distribution of wet soils. We assess the spatial consistency with which these wet soils occur for the 2008-2009 to 2011-2012 austral summers with complete coverage and partial coverage for 2003-2004 and 2006-2007 austral summers using a land cover classification. We also quantify the soil moisture of wetted soils using an artificial neural network (ANN). The ANN utilizes field radiometer data to retrieve estimates of surface moisture based on the spectral measurements and soil moisture samples collected during the 2010-2011 field season. The remote sensing based analyses of the wetted soils have shown the magnitude to vary greatly and how topography and regional microclimates influence the wetted soils in the MDV. The 2010-2011 austral summer provided the most wetted soil area, 10.21 km2, and 2008- 2009 covered the least, 5.38 km2. The ANN soil moisture distribution in the MDV shows values ranging from 0.36 % to over 19 %. We suggest that wet soils are a significant component of this cold desert land system and ecosystem.

1 aLangford, Z., L.1 aGooseff, Michael, N. uhttps://etda.libraries.psu.edu/catalog/1736400663nas a2200193 4500008004100000245008400041210006900125260001200194300001200206490000700218100001700225700001700242700001700259700001900276700002400295700001900319700002400338856010700362 2013 eng d00aThe carbon stable isotope biogeochemistry of streams, Taylor Valley, Antarctica0 acarbon stable isotope biogeochemistry of streams Taylor Valley A c05/2013 a26 - 360 v321 aLyons, Berry1 aLeslie, D.L.1 aHarmon, R.S.1 aNeumann, Klaus1 aWelch, Kathleen, A.1 aBisson, K., M.1 aMcKnight, Diane, M. uhttps://mcm.lternet.edu/content/carbon-stable-isotope-biogeochemistry-streams-taylor-valley-antarctica00625nas a2200145 4500008004100000245013000041210006900171260001100240490000600251100002300257700002000280700002100300700002400321856013400345 2013 eng d00aCORRIGENDUM: Don Juan Pond, Antarctica: Near-surface CaCl2-brine feeding Earth’s most saline lake and implications for Mars0 aCORRIGENDUM Don Juan Pond Antarctica Nearsurface CaCl2brine feed c3/20130 v31 aDickson, James, L.1 aHead, James, W.1 aLevy, Joseph, S.1 aMarchant, David, R. uhttps://mcm.lternet.edu/content/corrigendum-don-juan-pond-antarctica-near-surface-cacl2-brine-feeding-earth%E2%80%99s-most-saline00735nas a2200181 4500008004100000245015100041210006900192260001200261300001400273490000700287100002300294700002000317700002400337700002400361700002400385700001700409856012700426 2013 eng d00aDo Cryoconite Holes have the Potential to be Significant Sources of C, N, and P to Downstream Depauperate Ecosystems of Taylor Valley, Antarctica?0 aDo Cryoconite Holes have the Potential to be Significant Sources c11/2013 a440 - 4540 v451 aBagshaw, Elizabeth1 aTranter, Martyn1 aFountain, Andrew, G1 aWelch, Kathleen, A.1 aBasagic, Hassan, J.1 aLyons, Berry uhttps://mcm.lternet.edu/content/do-cryoconite-holes-have-potential-be-significant-sources-c-n-and-p-downstream-depauperate00577nas a2200145 4500008004100000245011500041210006900156260001200225490000600237100002300243700002000266700002100286700002400307856010000331 2013 eng d00aDon Juan Pond, Antarctica: Near-surface CaCl2-brine feeding Earth's most saline lake and implications for Mars0 aDon Juan Pond Antarctica Nearsurface CaCl2brine feeding Earths m c01/20130 v31 aDickson, James, L.1 aHead, James, W.1 aLevy, Joseph, S.1 aMarchant, David, R. uhttp://www.nature.com/srep/2013/130130/srep01166/full/srep01166.html?WT.ec_id=SREP-704-2013020100638nas a2200169 4500008004100000245013200041210006900173260001200242300001600254490000800270100002100278700002400299700002100323700002400344700001700368856008300385 2013 eng d00aGarwood Valley, Antarctica: A new record of Last Glacial Maximum to Holocene glaciofluvial processes in the McMurdo Dry Valleys0 aGarwood Valley Antarctica A new record of Last Glacial Maximum t c09/2013 a1484 - 15020 v1251 aLevy, Joseph, S.1 aFountain, Andrew, G1 aO'Connor, J., E.1 aWelch, Kathleen, A.1 aLyons, Berry uhttp://bulletin.geoscienceworld.org/content/early/2013/06/07/B30783.1.abstract00495nas a2200121 4500008004100000245009100041210006900132260001200201300001400213490000700227100002100234856011800255 2013 eng d00aHow big are the McMurdo Dry Valleys? Estimating ice-free area using Landsat image data0 aHow big are the McMurdo Dry Valleys Estimating icefree area usin c02/2013 a119 - 1200 v251 aLevy, Joseph, S. uhttps://mcm.lternet.edu/content/how-big-are-mcmurdo-dry-valleys-estimating-ice-free-area-using-landsat-image-data00643nas a2200169 4500008004100000245010200041210006900143260001200212300001100224490000600235100002000241700002300261700002100284700001900305700002200324856012700346 2013 eng d00aLocal and regional influences over soil microbial metacommunities in the Transantarctic Mountains0 aLocal and regional influences over soil microbial metacommunitie c11/2013 aart1360 v41 aSokol, Eric, R.1 aHerbold, Craig, W.1 aLee, Charles, K.1 aCary, Craig, S1 aBarrett, John, E. uhttps://mcm.lternet.edu/content/local-and-regional-influences-over-soil-microbial-metacommunities-transantarctic-mountains02033nas a2200229 4500008004100000245011500041210006900156260001200225300001100237490000600248520129700254100002701551700001901578700002101597700002901618700002001647700002001667700002301687700001801710700002401728856005101752 2013 eng d00aMicrobial growth under humic-free conditions in a supraglacial stream system on the Cotton Glacier, Antarctica0 aMicrobial growth under humicfree conditions in a supraglacial st c09/2013 a0350220 v83 aDuring the austral summers of 2004 and 2009, we sampled a supraglacial stream on the Cotton Glacier, Antarctica. The stream dissolved organic matter (DOM) was low (44–48 μM C) and lacked detectable humic fluorescence signatures. Analysis of the excitation emissions matrices (EEMs) indicated that amino-acid fluorophores dominated, consistent with DOM of microbial origin, with little humic-like fluorescence. In most aquatic ecosystems, humic DOM attenuates harmful UV radiation and its absence may represent an additional stressor influencing the microbial community. Nonetheless, the stream contained an active microbial assemblage with bacterial cell abundances from 2.94 × 104 to 4.97 × 105 cells ml−1, and bacterial production ranging from 58.8 to 293.2 ng C l−1 d−1. Chlorophyll-a concentrations ranged from 0.3 to 0.53 μg l−1 indicating that algal phototrophs were the probable source of the DOM. Microbial isolates produced a rainbow of pigment colors, suggesting adaptation to stress, and were similar to those from other cryogenic systems (Proteobacteria and Bacteroidetes lineages). Supraglacial streams provide an example of contemporary microbial processes on the glacier surface and a natural laboratory for studying microbial adaptation to the absence of humics.1 aForeman, Christine, M.1 aCory, Rose, M.1 aMorris, Cindy, E1 aSanClements, Michael, D.1 aSmith, Heidi, J1 aLisle, John, T.1 aMiller, Penney, L.1 aChin, Yu-Ping1 aMcKnight, Diane, M. uhttp://iopscience.iop.org/1748-9326/8/3/03502200803nas a2200217 4500008004100000245011600041210006900157260001200226300001400238490000700252100001900259700002700278700001700305700002000322700002400342700002800366700002300394700001800417700002400435856012600459 2013 eng d00aPhysicochemical and biological dynamics in a coastal Antarctic lake as it transitions from frozen to open water0 aPhysicochemical and biological dynamics in a coastal Antarctic l c12/2013 a663–6750 v251 aDieser, Markus1 aForeman, Christine, M.1 aJaros, Chris1 aLisle, John, T.1 aGreenwood, Mark, C.1 aLaybourn-Parry, Johanna1 aMiller, Penney, L.1 aChin, Yu-Ping1 aMcKnight, Diane, M. uhttps://mcm.lternet.edu/content/physicochemical-and-biological-dynamics-coastal-antarctic-lake-it-transitions-frozen-open00637nas a2200169 4500008004100000245013500041210006900176260001200245300001400257490000600271100002100277700002500298700002500323700002200348700003300370856006400403 2013 eng d00aSeasonal controls on snow distribution and aerial ablation at the snow-patch and landscape scales, McMurdo Dry Valleys, Antarctica0 aSeasonal controls on snow distribution and aerial ablation at th c09/2013 a917 - 9310 v71 aEveland, Jeffery1 aGooseff, Michael, N.1 aLampkin, Derrick, J.1 aBarrett, John, E.1 aTakacs-Vesbach, Cristina, D. uhttp://www.the-cryosphere.net/7/917/2013/tc-7-917-2013.html00493nas a2200145 4500008004100000245007100041210006900112260001200181300001400193490000700207100002500214700002200239700002100261856006500282 2013 eng d00aShallow groundwater systems in a polar desert, McMurdo Dry Valleys0 aShallow groundwater systems in a polar desert McMurdo Dry Valley c02/2013 a171 - 1830 v211 aGooseff, Michael, N.1 aBarrett, John, E.1 aLevy, Joseph, S. uhttp://link.springer.com/article/10.1007%2Fs10040-012-0926-300619nas a2200169 4500008004100000245011800041210006900159260001200228300001600240490000700256100002100263700002500284700002500309700002200334700003300356856006000389 2013 eng d00aSpatial and temporal patterns of snow accumulation and aerial ablation across the McMurdo Dry Valleys, Antarctica0 aSpatial and temporal patterns of snow accumulation and aerial ab c09/2013 a2864 - 28750 v271 aEveland, Jeffery1 aGooseff, Michael, N.1 aLampkin, Derrick, J.1 aBarrett, John, E.1 aTakacs-Vesbach, Cristina, D. uhttp://onlinelibrary.wiley.com/doi/10.1002/hyp.9407/pdf00488nas a2200145 4500008004100000245007700041210006900118260001200187300001200199490000700211100002100218700001700239700001700256856006900273 2013 eng d00aUnderstanding Terrestrial Ecosystem Response to Antarctic Climate Change0 aUnderstanding Terrestrial Ecosystem Response to Antarctic Climat c01/2013 a33 - 330 v941 aLevy, Joseph, S.1 aLyons, Berry1 aAdams, Byron uhttp://onlinelibrary.wiley.com/doi/10.1002/2013EO030009/abstract00730nas a2200193 4500008004100000245009900041210006900140300001100209100002100220700002400241700002500265700002200290700002200312700002400334700001700358700002200375700002000397856011900417 2013 eng d00aWater track modification of soil ecosystems in the Lake Hoare basin, Taylor Valley, Antarctica0 aWater track modification of soil ecosystems in the Lake Hoare ba a1 - 101 aLevy, Joseph, S.1 aFountain, Andrew, G1 aGooseff, Michael, N.1 aBarrett, John, E.1 aVantreese, Robert1 aWelch, Kathleen, A.1 aLyons, Berry1 aNielsen, Uffe, N.1 aWall, Diana, H. uhttps://mcm.lternet.edu/content/water-track-modification-soil-ecosystems-lake-hoare-basin-taylor-valley-antarctica00656nas a2200181 4500008004100000245009100041210006900132260001200201100002100213700002200234700002300256700002100279700002000300700002400320700002500344700002400369856008100393 2012 eng d00aBacteria and diatom co-occurrence patterns in microbial mats from polar desert streams0 aBacteria and diatom cooccurrence patterns in microbial mats from c10/20121 aStanish, Lee, F.1 aO'Neill, Sean, P.1 aGonzález, Antonio1 aLegg, Teresa, M.1 aKnelman, Joseph1 aMcKnight, Diane, M.1 aSpaulding, Sarah, A.1 aNemergut, Diana, R. uhttp://onlinelibrary.wiley.com/doi/10.1111/j.1462-2920.2012.02872.x/abstract04191nas a2200445 4500008004100000022001400041245005900055210005900114260001600173300001400189490000800203520302300211100002203234700001603256700001903272700001503291700001803306700002003324700001503344700001903359700001603378700001303394700001503407700001803422700001303440700002203453700001503475700001503490700002303505700001303528700001903541700001703560700001503577700001703592700001803609700002003627700001603647700002003663856006203683 2012 eng d a0036-807500aChallenges to the Future Conservation of the Antarctic0 aChallenges to the Future Conservation of the Antarctic cJan-07-2013 a158 - 1590 v3373 a

The Antarctic Treaty System, acknowledged as a successful model of cooperative regulation of one of the globe's largest commons (1), is under substantial pressure. Concerns have been raised about increased stress on Antarctic systems from global environmental change and growing interest in the region's resources (23). Although policy-makers may recognize these challenges, failure to respond in a timely way can have substantial negative consequences. We provide a horizon scan, a systematic means for identifying emerging trends and assisting decision-makers in identifying policies that address future challenges (23). Previous analyses of conservation threats in the Antarctic have been restricted to matters for which available evidence is compelling (4). We reconsider these concerns because they might escalate quickly, judging from recent rapid environmental change in parts of Antarctica and increasing human interest in the region (see the map). We then focus on a more distant time horizon.

1 aChown, Steven, L.1 aLee, J., E.1 aHughes, K., A.1 aBarnes, J.1 aBarrett, P.J.1 aBergstrom, D.M.1 aConvey, P.1 aCowan, Don, A.1 aCrosbie, K.1 aDyer, G.1 aFrenot, Y.1 aGrant, S., M.1 aHerr, D.1 aKennicutt, M., C.1 aLamers, M.1 aMurray, A.1 aPossingham, H., P.1 aReid, K.1 aRiddle, M., J.1 aRyan, P., G.1 aSanson, L.1 aShaw, J., D.1 aSparrow, M.D.1 aSummerhayes, C.1 aTerauds, A.1 aWall, Diana, H. uhttp://www.sciencemag.org/cgi/doi/10.1126/science.122282100683nas a2200205 4500008004100000245009900041210006900140260001200209100001700221700002300238700001700261700002200278700002100300700002600321700001700347700002200364700002000386700002200406856004900428 2012 eng d00aCross-biome metagenomic analyses of soil microbial communities and their functional attributes0 aCrossbiome metagenomic analyses of soil microbial communities an c11/20121 aFierer, Noah1 aLeff, Jonathan, W.1 aAdams, Byron1 aNielsen, Uffe, N.1 aBates, Scott, T.1 aLauber, Christian, L.1 aOwens, Sarah1 aGilbert, Jack, A.1 aWall, Diana, H.1 aCaporaso, Gregory uwww.pnas.org/cgi/doi/10.1073/pnas.121521011000619nas a2200193 4500008004100000245006400041210005800105260001100163300001100174490000700185100001700192700002400209700002900233700001700262700002400279700001600303700002100319856008500340 2012 eng d00aThe geochemistry of upland ponds, Taylor Valley, Antarctica0 ageochemistry of upland ponds Taylor Valley Antarctica c2/2012 a3 - 140 v241 aLyons, Berry1 aWelch, Kathleen, A.1 aGardner, Christopher, B.1 aJaros, Chris1 aMoorhead, Daryl, L.1 aKnoepfle, J1 aDoran, Peter, T. uhttp://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=848335100514nas a2200145 4500008004100000245006300041210005600104260001200160490000700172100002100179700002400200700002400224700001700248856010300265 2012 eng d00aHypersaline “wet patches” in Taylor Valley, Antarctica0 aHypersaline wet patches in Taylor Valley Antarctica c03/20120 v391 aLevy, Joseph, S.1 aFountain, Andrew, G1 aWelch, Kathleen, A.1 aLyons, Berry uhttps://mcm.lternet.edu/content/hypersaline-%E2%80%9Cwet-patches%E2%80%9D-taylor-valley-antarctica00684nas a2200193 4500008004100000245011200041210006900153260001200222300001400234490000700248100001800255700002200273700002100295700002100316700002800337700002000365700002800385856007700413 2012 eng d00aMicrobial dynamics and flagellate grazing during transition to winter in Lakes Hoare and Bonney, Antarctica0 aMicrobial dynamics and flagellate grazing during transition to w c11/2012 a449 - 4580 v821 aThurman, Jill1 aParry, Jacqueline1 aHill, Philip, J.1 aPriscu, John, C.1 aVick-Majors, Trista, J.1 aChiuchiolo, Amy1 aLaybourn-Parry, Johanna uhttp://onlinelibrary.wiley.com/doi/10.1111/j.1574-6941.2012.01423.x/full00621nas a2200181 4500008004100000245010500041210006900146260001200215300001200227490000700239100002000246700002400266700001900290700001700309700002100326700002100347856007100368 2012 eng d00aPerchlorate and chlorate biogeochemistry in ice-covered lakes of the McMurdo Dry Valleys, Antarctica0 aPerchlorate and chlorate biogeochemistry in icecovered lakes of  c12/2012 a19 - 300 v981 aJackson, Andrew1 aDavila, Alfonso, F.1 aEstrada, Nubia1 aLyons, Berry1 aCoates, John, D.1 aPriscu, John, C. uhttp://www.sciencedirect.com/science/article/pii/S001670371200511X00474nas a2200133 4500008004100000245010000041210006900141260002700210490000900237100001200246700002000258700001700278856004500295 2012 eng d00aTaylor’s ‘missing’ lake: Integrating history into LTER research in the McMurdo Dry Valley0 aTaylor s missing lake Integrating history into LTER research in  aAlbuquerquebLTER News0 v20131 aKhan, A1 aHowkins, Adrian1 aLyons, Berry uhttp://news.lternet.edu/Article2568.html00581nas a2200169 4500008004100000245008600041210006900127260001200196300001400208490000600222100002500228700002400253700002100277700002400298700001700322856007200339 2011 eng d00aHydrological Connectivity of the Landscape of the McMurdo Dry Valleys, Antarctica0 aHydrological Connectivity of the Landscape of the McMurdo Dry Va c09/2011 a666 - 6810 v51 aGooseff, Michael, N.1 aMcKnight, Diane, M.1 aDoran, Peter, T.1 aFountain, Andrew, G1 aLyons, Berry uhttp://onlinelibrary.wiley.com/doi/10.1111/j.1749-8198.2011.00445.x00651nas a2200205 4500008004100000022001400041245007900055210006900134260001200203300000800215490000700223100002000230700001700250700002200267700001800289700002700307700002100334700002500355856006500380 2011 eng d a0954-102000aLong-term ecosystem networks to record change: an international imperative0 aLongterm ecosystem networks to record change an international im c06/2011 a2090 v231 aWall, Diana, H.1 aLyons, Berry1 aChown, Steven, L.1 aConvey, Peter1 aHoward-Williams, Clive1 aQuesada, Antonio1 aVincent, Warwick, F. uhttp://www.journals.cambridge.org/abstract_S095410201100031900668nas a2200205 4500008004100000022001400041245010700055210006900162260001200231300001600243490000700259100001900266700001600285700001800301700002400319700002000343700002400363700002000387856005500407 2011 eng d a0722-406000aMicroclimate impacts of passive warming methods in Antarctica: implications for climate change studies0 aMicroclimate impacts of passive warming methods in Antarctica im c10/2011 a1421 - 14350 v341 aBokhorst, Stef1 aHuiskes, Ad1 aConvey, Peter1 aSinclair, Brent, J.1 aLebouvier, Marc1 aVan de Vijver, Bart1 aWall, Diana, H. uhttp://link.springer.com/10.1007/s00300-011-0997-y00632nas a2200181 4500008004100000245008400041210006900125260001100194300001400205490000700219100002200226700002000248700001400268700001700282700001700299700002300316856011100339 2011 eng d00aNematode communities of Byers Peninsula, Livingston Island, maritime Antarctica0 aNematode communities of Byers Peninsula Livingston Island mariti c8/2011 a349 - 3570 v231 aNielsen, Uffe, N.1 aWall, Diana, H.1 aLi, Grace1 aToro, Manuel1 aAdams, Byron1 aVirginia, Ross, A. uhttps://mcm.lternet.edu/content/nematode-communities-byers-peninsula-livingston-island-maritime-antarctica00685nam a2200193 4500008004100000020002200041245010600063210006900169260003600238300001400274490000800288100001900296700002500315700002400340700002300364700002600387700002000413856005800433 2011 eng d a978-94-007-1363-500aSpectral Methods to Advance Understanding of Dissolved Organic Carbon Dynamics in Forested Catchments0 aSpectral Methods to Advance Understanding of Dissolved Organic C aDordrechtbSpringer Netherlands a117 - 1350 v2161 aCory, Rose, M.1 aBoyer, Elizabeth, W.1 aMcKnight, Diane, M.1 aLevia, Delphis, F.1 aCarlyle-Moses, Darryl1 aTanaka, Tadashi uhttp://www.springerlink.com/content/lv9365ml54192m29/00630nas a2200169 4500008004100000245013600041210006900177260001200246300001400258490000800272100002100280700002400301700002500325700002400350700001700374856006900391 2011 eng d00aWater tracks and permafrost in Taylor Valley, Antarctica: Extensive and shallow groundwater connectivity in a cold desert ecosystem0 aWater tracks and permafrost in Taylor Valley Antarctica Extensiv c11/2011 a2295-23110 v1231 aLevy, Joseph, S.1 aFountain, Andrew, G1 aGooseff, Michael, N.1 aWelch, Kathleen, A.1 aLyons, Berry uhttp://bulletin.geoscienceworld.org/content/123/11-12/2295.short00776nas a2200229 4500008004100000245011100041210006900152260001200221300001400233490000700247100002700254700001900281700002000300700001900320700002800339700002000367700001700387700002300404700001800427700002400445856007700469 2011 eng d00aWhen a habitat freezes solid: microorganisms over-winter within the ice column of a coastal Antarctic lake0 aWhen a habitat freezes solid microorganisms overwinter within th c06/2011 a401 - 4120 v761 aForeman, Christine, M.1 aDieser, Markus1 aGreenwood, Mark1 aCory, Rose, M.1 aLaybourn-Parry, Johanna1 aLisle, John, T.1 aJaros, Chris1 aMiller, Penney, L.1 aChin, Yu-Ping1 aMcKnight, Diane, M. uhttp://onlinelibrary.wiley.com/doi/10.1111/j.1574-6941.2011.01061.x/full05611nas a2200229 4500008004100000245006100041210006000102260004000162490000900202520491500211653002205126653001505148653000905163653002605172653001705198653002405215653002405239653001505263100002505278700001705303856006105320 2010 eng d00aAeolian sediments of the McMurdo Dry Valleys, Antarctica0 aAeolian sediments of the McMurdo Dry Valleys Antarctica aColumbus, OHbOhio State University0 vM.S.3 a

The role of dust has become a topic of increasing interest in the interface between climate and geological/ecological sciences. Dust emitted from major sources, the majority of which are desert regions in the Northern Hemisphere, is transported via suspension in global wind systems and incorporated into the biogeochemical cycles of the ecosystems where it is ultimately deposited. While emissions within the McMurdo Dry Valleys (MDV) region of Antarctica are small compared to other source regions, the redistribution of new, reactive material by wind may be important to sustaining life in the ecosystem.


The interaction of the dry, warm foehn winds and the cool, moist coastal breezes “recycles” soil particles throughout the landscape. The bulk of sediment movement occurs during foehn events in the winter that redistribute material throughout the MDV. To understand the source and transfer of this material samples were collected early in the austral summer (November 2008) prior to the initiation of extensive ice melt from glacial and lake surfaces, aeolian landforms, and elevated sediment traps. These were preserved and processed for grain size distribution and major element composition at the sand and silt particle sizes. Major elemental oxide analysis indicated that the silt and sand size particles are of different composition: SiO2 values for silt range from 50 to 59% by weight and for sand range from 59 to 74%. When compared to the elemental oxide composition four rock types present in the MDV, the composition of the silt indicates a mixing influenced mostly by the igneous rock types (Ferrar Dolerite and McMurdo Volcanic basanite) and sand a mixing influenced largely by the sedimentary rocks (Beacon Sandstone and the metasedimentary Basement Complex). This could imply a local source of the aeolian material that is corroborated by low CIA values at both particle sizes (44-57%) indicating low degrees of chemical weathering. In addition, comparison of 87Sr/86Sr and 143Nd/144Nd to values published for the major MDV rock types and ice core dust to values analyzed in 3 silt size glacier sample and one bulk glacier sample also indicates a local source of sediments and that it is not likely to be transferred inland.


During the melt season, the aeolian material is actively solubilized where it interacts with water, releasing solutes and vital bioavailable nutrients throughout the aquatic system. Differences in the chemistry of supra- and proglacial streams as well as lake surface waters may be derived from the deposition and dissolution of these aeolian sediments. To simulate these conditions, a two-step leaching method using deionized water to represent glacial melt in field conditions was employed and leachates analyzed for major ion and nutrient constituents. Leachates represent a small degree (<0.7%) of dissolution of major elements, and are solubilized to a greater extent from samples closer to the coast or with increased silt content. The composition of the leachates reflects the dissolution of the major salts found in the MDV. Leach 1 (cold water) indicates that Na- and Cl-bearing salt phases are dissolved to a greater extent than seen in Leach 2 (freeze-thaw). Conversely, Leach 2 compositions indicate that carbonate mineral dissolution and Mg-bearing silicate weathering are proceeding to a greater extent than in Leach 1.


Inorganic N:P ratios follow the same patterns of nutrient limitations based on the Redfield Ratio found by Priscu (1995) in the terminal lakes of the Taylor Valley: N-limited in the Fryxell and Hoare basins (east) and P-limited in the Bonney basin (west). This is also consistent with the age of the tills in the area, as found by Gudding (2003). The concentration of soluble Fe in the leachates is about the same as soluble inorganic P, and thus is not a limiting nutrient in the leachates. Comparison of total dissolved N and P to their inorganic counterparts reveals increased organic nutrients in the glacier and lake leachates that may indicate the influence of biota. Nutrient fluxes based on known sediment fluxes from elevated sediment traps deployed throughout the MDV and the composition of these leachates range from 0.34-330 g a-1 for N, 0.02-8.3 g a-1 for P, and 0.03-8.6 g a-1 for Fe. These are at least two orders of magnitude less than calculated loads from streams to the lakes in the Taylor Valley and, thus, should be considered underestimations or minima.


This work provides the first investigation into the composition and source of aeolian transported materials in the MDV, as well of what is potentially solubilized from it during the austral summer melt season. In addition, it will contribute to the understanding of the interplay between aeolian and aquatic processes in the MDV and further the understanding of this unique ecosystem.

10aaeolian transport10aAntarctica10adust10aexperimental leaching10ageochemistry10aMcMurdo Dry Valleys10asediment provenance10aweathering1 aDeuerling, Kelly, M.1 aLyons, Berry uhttp://rave.ohiolink.edu/etdc/view?acc_num=osu129052486200722nas a2200193 4500008004100000020001800041245008800059210006900147260004200216300001400258100002500272700002400297700001700321700001700338700002100355700001700376700002400393856011100417 2010 eng d a978052188919300aAntarctic McMurdo Dry Valley stream ecosystems as analog to fluvial systems on Mars0 aAntarctic McMurdo Dry Valley stream ecosystems as analog to fluv aCambridgebCambridge University Press a139 - 1591 aGooseff, Michael, N.1 aMcKnight, Diane, M.1 aCarr, M., H.1 aBaeseman, J.1 aDoran, Peter, T.1 aLyons, Berry1 aMcKnight, Diane, M. uhttps://mcm.lternet.edu/content/antarctic-mcmurdo-dry-valley-stream-ecosystems-analog-fluvial-systems-mars00639nas a2200169 4500008004100000245009600041210006900137260001200206300002800218490000900246100002500255700002500280700001000305700002000315700001700335856011700352 2010 eng d00aThe Antarctic Nematode Plectus murrayi: An Emerging Model to Study Multiple Stress Survival0 aAntarctic Nematode Plectus murrayi An Emerging Model to Study Mu c11/2010 apdb.emo142 - pdb.emo1420 v20101 aAdhikari, Bishwo, N.1 aTomasel, Cecilia, M.1 aLi, G1 aWall, Diana, H.1 aAdams, Byron uhttps://mcm.lternet.edu/content/antarctic-nematode-plectus-murrayi-emerging-model-study-multiple-stress-survival00620nas a2200205 4500008004100000245005400041210005300095260000900148490000700157100001900164700002000183700001600203700001900219700002100238700001700259700001400276700001300290700002600303856008500329 2010 eng d00aBiogeochemical weathering under ice: Size matters0 aBiogeochemical weathering under ice Size matters c20100 v241 aWadham, J., L.1 aTranter, Martyn1 aSkidmore, M1 aHodson, A., J.1 aPriscu, John, C.1 aLyons, Berry1 aSharp, M.1 aWynn, P.1 aJackson, Margaret, S. uhttps://mcm.lternet.edu/content/biogeochemical-weathering-under-ice-size-matters00534nas a2200169 4500008004100000245005300041210005300094260001200147300003200159490000900191100002500200700002500225700001000250700002000260700001700280856006700297 2010 eng d00aCulturing the Antarctic Nematode Plectus murrayi0 aCulturing the Antarctic Nematode Plectus murrayi c11/2010 apdb.prot5522 - pdb.prot55220 v20101 aAdhikari, Bishwo, N.1 aTomasel, Cecilia, M.1 aLi, G1 aWall, Diana, H.1 aAdams, Byron uhttp://cshprotocols.cshlp.org/content/2010/11/pdb.emo142.short00763nam a2200241 4500008004100000020001800041245005800059210005800117260004300175300000800218490000600226653002200232100002100254700001700275700002400292700002400316700002500340700003300365700002200398700002000420700001800440856006300458 2010 eng d a978051171225800aLife in Antarctic Deserts and Other Cold Environments0 aLife in Antarctic Deserts and Other Cold Environments aCambridgebCambridge University Press. a3070 v510aPlanetary Science1 aDoran, Peter, T.1 aLyons, Berry1 aMcKnight, Diane, M.1 aMcKnight, Diane, M.1 aGooseff, Michael, N.1 aTakacs-Vesbach, Cristina, D.1 aMikucki, Jill, A.1 aTranter, Martyn1 aSun, Henry, J uhttp://ebooks.cambridge.org/ebook.jsf?bid=CBO978051171225800627nas a2200145 4500008004100000245010900041210006900150100001700219700001700236700002800253700002900281700002100310700002400331856012600355 2010 eng d00aPhysiochemical properties influencing biomass abundance and primary production in Lake Hoare, Antarctica0 aPhysiochemical properties influencing biomass abundance and prim1 aHerbei, Radu1 aLyons, Berry1 aLaybourn-Parry, Johanna1 aGardner, Christopher, B.1 aPriscu, John, C.1 aMcKnight, Diane, M. uhttps://mcm.lternet.edu/content/physiochemical-properties-influencing-biomass-abundance-and-primary-production-lake-hoare00649nas a2200169 4500008004100000020001800041245010800059210006900167260004200236300001400278100002200292700001700314700001500331700002200346700002100368856009000389 2010 eng d a978052188919300aSaline lakes and ponds in the McMurdo Dry Valleys: ecological analogs to martian paleolake environments0 aSaline lakes and ponds in the McMurdo Dry Valleys ecological ana aCambridgebCambridge University Press a160 - 1941 aMikucki, Jill, A.1 aLyons, Berry1 aHawes, Ian1 aLanoil, Brian, D.1 aDoran, Peter, T. uhttp://ebooks.cambridge.org/chapter.jsf?bid=CBO9780511712258&cid=CBO9780511712258A01300685nas a2200193 4500008004100000245010500041210006900146260001200215300001400227490000700241100002400248700001700272700001900289700002900308700002500337700002400362700002100386856008400407 2010 eng d00aSpatial variations in the geochemistry of glacial meltwater streams in the Taylor Valley, Antarctica0 aSpatial variations in the geochemistry of glacial meltwater stre c12/2010 a662 - 6720 v221 aWelch, Kathleen, A.1 aLyons, Berry1 aWhisner, Carla1 aGardner, Christopher, B.1 aGooseff, Michael, N.1 aMcKnight, Diane, M.1 aPriscu, John, C. uhttp://www.montana.edu/lkbonney/DOCS/Publications/WelchEtAl2010Geochemistry.pdf00918nas a2200325 4500008004100000245006400041210006300105300001200168490000700180100001700187700001600204700001400220700001600234700001500250700001400265700002500279700001500304700001300319700002000332700002600352700001600378700001700394700001900411700001300430700001500443700001200458700001500470700001500485856009200500 2009 eng d00aAccelerate Synthesis in Ecology and Environmental Sciences.0 aAccelerate Synthesis in Ecology and Environmental Sciences a699-7010 v591 aCarpenter, S1 aLundberg, P1 aMangel, M1 aMerchant, N1 aMurdoch, W1 aPalmer, M1 aPeters, Debra, P. C.1 aPickett, S1 aSmith, K1 aWall, Diana, H.1 aZimmerman, Maggie, K.1 aArmbrust, E1 aArzberger, E1 aChapin, F., S.1 aElser, J1 aHackett, E1 aIves, A1 aKareiva, P1 aLeibold, M uhttps://mcm.lternet.edu/content/accelerate-synthesis-ecology-and-environmental-sciences01755nas a2200241 4500008004100000245006900041210006500110260001200175300001200187490000800199520109500207653001101302100002201313700001501335700001601350700001501366700001601381700001401397700001301411700002101424700001101445856005701456 2009 eng d00aA Contemporary Microbially Maintained Subglacial Ferrous "Ocean"0 aContemporary Microbially Maintained Subglacial Ferrous Ocean c04/2009 a397-4000 v3243 a

An active microbial assemblage cycles sulfur in a sulfate-rich, ancient marine brine beneath Taylor Glacier, an outlet glacier of the East Antarctic Ice Sheet, with Fe(III) serving as the terminal electron acceptor. Isotopic measurements of sulfate, water, carbonate, and ferrous iron and functional gene analyses of adenosine 5′-phosphosulfate reductase imply that a microbial consortium facilitates a catalytic sulfur cycle. These metabolic pathways result from a limited organic carbon supply because of the absence of contemporary photosynthesis, yielding a subglacial ferrous brine that is anoxic but not sulfidic. Coupled biogeochemical processes below the glacier enable subglacial microbes to grow in extended isolation, demonstrating how analogous organic-starved systems, such as Neoproterozoic oceans, accumulated Fe(II) despite the presence of an active sulfur cycle.

10aBiggie1 aMikucki, Jill, A.1 aPearson, A1 aJohnston, D1 aTurchyn, A1 aFarquhar, J1 aSchrag, D1 aAnbar, A1 aPriscu, John, C.1 aLee, P uhttp://www.sciencemag.org/content/324/5925/397.short01451nas a2200481 4500008004100000245006900041210006900110260001200179300001600191490001400207100002200221700002200243700002200265700002500287700002400312700002600336700001800362700001800380700002100398700002200419700002800441700001700469700001800486700002200504700002000526700002300546700002400569700002100593700001900614700002200633700001800655700002500673700001800698700002600716700002500742700002100767700002000788700002300808700002700831700002700858700002600885856005800911 2009 eng d00aLakes and reservoirs as regulators of carbon cycling and climate0 aLakes and reservoirs as regulators of carbon cycling and climate c11/2009 a2298–23140 v54 part 21 aTranvik, Lars, J.1 aDowning, John, A.1 aCotner, James, B.1 aLoiselle, Steven, A.1 aStriegl, Robert, G.1 aBallatore, Thomas, J.1 aDillon, Peter1 aFinlay, Kerri1 aFortino, Kenneth1 aKnoll, Lesley, B.1 aKortelainen, Pirkko, L.1 aKutser, Tiit1 aLarsen, Soren1 aLaurion, Isabelle1 aLeech, Dina, M.1 aMcCallister, Leigh1 aMcKnight, Diane, M.1 aMelack, John, M.1 aOverholt, Erin1 aPorter, Jason, A.1 aPrairie, Yves1 aRenwick, William, H.1 aRoland, Fabio1 aSherman, Bradford, S.1 aSchindler, David, W.1 aSobek, Sebastian1 aTremblay, Alain1 aVanni, Michael, J.1 aVerschoor, Antonie, M.1 avon Wachenfeldt, Eddie1 aWeyhenmeyer, Gesa, A. uhttp://aslo.org/lo/toc/vol_54/issue_6_part_2/2298.pdf00380nas a2200133 4500008004100000245002400041210002400065260002700089300001200116100002100128700002700149700001700176856005300193 2009 eng d00aLakes of Antarctica0 aLakes of Antarctica aOxfordbElsevier Press a555-5661 aPriscu, John, C.1 aForeman, Christine, M.1 aLikens, G.E. uhttps://mcm.lternet.edu/content/lakes-antarctica00718nas a2200241 4500008004100000245007300041210006900114300001200183490000600195100001500201700001300216700001800229700002000247700001600267700001300283700001200296700001400308700001500322700001500337700001300352700001300365856009800378 2009 eng d00aManaging for ocean biodiversity to sustain marine ecosystem services0 aManaging for ocean biodiversity to sustain marine ecosystem serv a204-2110 v71 aPalumbi, S1 aNorse, E1 aStachowicz, J1 aWall, Diana, H.1 aSandifer, P1 aAllan, J1 aBeck, M1 aFautin, D1 aFogerty, M1 aHalpern, B1 aIncze, L1 aLeong, J uhttps://mcm.lternet.edu/content/managing-ocean-biodiversity-sustain-marine-ecosystem-services00480nas a2200109 4500008004100000245008700041210006900128260003000197100001600227700001700243856011000260 2009 eng d00aThe Minor Alkaline Earth Element and Alkali Metal Behavior in Closed-basin Lakes0 aMinor Alkaline Earth Element and Alkali Metal Behavior in Closed bThe Ohio State University1 aWitherow, R1 aLyons, Berry uhttps://mcm.lternet.edu/content/minor-alkaline-earth-element-and-alkali-metal-behavior-closed-basin-lakes00633nas a2200157 4500008004100000245012400041210006900165300001200234100001000246700001800256700001000274700002600284700002000310700002100330856012400351 2009 eng d00aMolecular profiling of soil animal diversity in natural ecosystems: incongruence of molecular and morphological results0 aMolecular profiling of soil animal diversity in natural ecosyste a849-8571 aWu, T1 aAyres, Edward1 aLi, G1 aBardgett, Richard, D.1 aWall, Diana, H.1 aGarey, James, R. uhttps://mcm.lternet.edu/content/molecular-profiling-soil-animal-diversity-natural-ecosystems-incongruence-molecular-and00641nas a2200157 4500008004100000245014100041210006900182300001200251490000800263100001600271700002100287700001800308700001700326700001700343856012300360 2009 eng d00aParticulate organic and dissolved inorganic carbon stable isotopic compositions in Taylor Valley lakes, Antarctica: the effect of legacy0 aParticulate organic and dissolved inorganic carbon stable isotop a139-1560 v6321 aKnoepfle, J1 aDoran, Peter, T.1 aKenig, Fabien1 aLyons, Berry1 aGalchenko, V uhttps://mcm.lternet.edu/content/particulate-organic-and-dissolved-inorganic-carbon-stable-isotopic-compositions-taylor00399nas a2200109 4500008004100000245006100041210005500102300001200157100002300169700001700192856008000209 2009 eng d00aThe saline lakes of the McMurdo Dry Valleys, Antarctica,0 asaline lakes of the McMurdo Dry Valleys Antarctica a321-3481 aGreen, William, J.1 aLyons, Berry uhttps://mcm.lternet.edu/content/saline-lakes-mcmurdo-dry-valleys-antarctica00835nas a2200289 4500008004100000245006600041210006500107490000700172100002300179700002000202700001600222700001600238700001700254700001400271700001200285700001200297700001700309700001600326700001900342700001400361700001300375700002200388700001500410700001500425700001900440856008600459 2009 eng d00aState of the Antarctic and the Southern Ocean climate system,0 aState of the Antarctic and the Southern Ocean climate system0 v471 aMayewski, Paul, A.1 aBromwich, David1 aCampbell, H1 aHamilton, G1 aLyons, Berry1 aMaasch, K1 aAoki, S1 aXiao, C1 avan Ommen, T1 aMeredith, M1 aSummerhayes, C1 aTurner, J1 aWorby, A1 aBarrett, John, E.1 aCasassa, G1 aBertler, N1 aBracegirdle, T uhttps://mcm.lternet.edu/content/state-antarctic-and-southern-ocean-climate-system00464nas a2200157 4500008004100000245004100041210004100082300001200123490000700135100001600142700002000158700002600178700002100204700002800225856005300253 2008 eng d00aBacteriophage in polar inland waters0 aBacteriophage in polar inland waters a167-1750 v121 aSawstrom, C1 aLisle, John, T.1 aAnesio, Alexandre, M.1 aPriscu, John, C.1 aLaybourn-Parry, Johanna u/reports/lakes/SawstromEtAl2008Bacteriophage.pdf00512nas a2200133 4500008004100000245006300041210006200104260003600166100001700202700001400219700002500233700002800258856009200286 2008 eng d00aBiogeochemical processes in high-latitude lakes and rivers0 aBiogeochemical processes in highlatitude lakes and rivers aOxfordbOxford University Press1 aLyons, Berry1 aFinlay, J1 aVincent, Warwick, F.1 aLaybourn-Parry, Johanna uhttps://mcm.lternet.edu/content/biogeochemical-processes-high-latitude-lakes-and-rivers00522nas a2200121 4500008004100000245009800041210006900139260003000208490001000238100001900248700001700267856011600284 2008 eng d00aThe geochemistry of glacier snow and melt: The Oregon Cascades and Taylor Valley, Antarctica.0 ageochemistry of glacier snow and melt The Oregon Cascades and Ta bThe Ohio State University0 vPh.D.1 aFortner, Sarah1 aLyons, Berry uhttps://mcm.lternet.edu/content/geochemistry-glacier-snow-and-melt-oregon-cascades-and-taylor-valley-antarctica02787nas a2200241 4500008004100000245002300041210002300064250000600087300001000093490000700103520220500110653001102315653001702326100001402343700002602357700002002383700002402403700001402427700002102441700002802462700001502490856004002505 2008 eng d00aGlacial ecosystems0 aGlacial ecosystems a1 a41-670 v783 a
There is now compelling evidence that microbially mediated reactions impart a significant effect upon the dynamics, composition, and abundance of nutrients in glacial melt water. Consequently, we must now consider ice masses as ecosystem habitats in their own right and address their diversity, functional potential, and activity as part of alpine and polar environments. Although such research is already underway, its fragmentary nature provides little basis for developing modern concepts of glacier ecology. This paper therefore provides a much-needed framework for development by reviewing the physical, biogeochemical, and microbiological characteristics of microbial habitats that have been identified within glaciers and ice sheets. Two key glacial ecosystems emerge, one inhabiting the glacier surface (the supraglacial ecosystem) and one at the ice-bed interface (the subglacial ecosystem). The supraglacial ecosystem is characterized by a diverse consortium of microbes (usually bacteria, algae, phytoflagellates, fungi, viruses and occasional rotifers, tardigrades, and diatoms) within the snowpack, supraglacial streams, and melt pools (cryoconite holes). The subglacial system is dominated by aerobic/anaerobic bacteria and most probably viruses in basal ice/till mixtures and subglacial lakes. A third, so-called englacial ecosystem is also described, but it is demonstrated that conditions within glacier ice are sufficient to make metabolic activity and its impact upon nutrient dynamics negligible at the glacier scale.
 
Consideration of the surface and internal heat balances of the glacier show that all glacial ecosystems are sensitive to climate change, although at different timescales. Thus, while rapid, melt-driven habitat changes lead to melt-out, resuscitation, and redistribution of microorganisms in many supraglacial ecosystems, much slower climatic and glacial mass-balance processes effect such changes in the subglacial ecosystem. Paradoxically, it is shown that these forces have brought about net refreezing and the onset of cryostasis in the subglacial ecosystems of many Arctic glaciers subject to thinning in recent decades.
10aBiggie10asnow ecology1 aHodson, A1 aAnesio, Alexandre, M.1 aTranter, Martyn1 aFountain, Andrew, G1 aOsborn, M1 aPriscu, John, C.1 aLaybourn-Parry, Johanna1 aSattler, B uhttp://dx.doi.org/10.1890/07-0187.101642nas a2200541 4500008004100000245010100041210006900142260001200211300001400223490000700237100002000244700002300264700002100287700002300308700002900331700002300360700002200383700002400405700001700429700002000446700002100466700002600487700002000513700002200533700002400555700002400579700001900603700002200622700002200644700002100666700001700687700002200704700002300726700001500749700001900764700002100783700002100804700002400825700002200849700002300871700002600894700002300920700001900943700002900962700001500991700001701006856007701023 2008 eng d00aGlobal decomposition experiment shows soil animal impacts on decomposition are climate dependent0 aGlobal decomposition experiment shows soil animal impacts on dec c11/2008 a2661-26770 v141 aWall, Diana, H.1 aBradford, Mark, A.1 aStJohn, Mark, G.1 aTrofymow, John, A.1 aBehan-Pelletier, Valerie1 aBignell, David, E.1 aDangerfield, Mark1 aParton, William, J.1 aRusek, Josef1 aVoigt, Winfried1 aWolters, Volkmar1 aGardel, Holley, Zadeh1 aAyuke, Fred, O.1 aBashford, Richard1 aBeljakova, Olga, I.1 aBohlen, Patrick, J.1 aBrauman, Alain1 aFlemming, Stephen1 aHenschel, Joh, R.1 aJohnson, Dan, L.1 aJones, Hefin1 aKovarova, Marcela1 aKranabetter, Marty1 aKutny, Les1 aLin, Kuo-Chuan1 aMaryati, Mohamed1 aMasse, Dominique1 aPokarzhevsk, Andrei1 aRahman, Homathevi1 aSabara, Millor, G.1 aSalamon, Joerg-Alfred1 aSwift, Michael, J.1 aVarela, Amanda1 aVasconcelos, Heraldo, L.1 aWhite, Don1 aZou, Xiaming uhttp://onlinelibrary.wiley.com/doi/10.1111/j.1365-2486.2008.01672.x/full00521nas a2200157 4500008004100000245003800041210003600079260003600115100002400151700002500175700002500200700001600225700002500241700002800266856006900294 2008 eng d00aHigh-latitude rivers and streams.0 aHighlatitude rivers and streams aOxfordbOxford University Press1 aMcKnight, Diane, M.1 aGooseff, Michael, N.1 aVincent, Warwick, F.1 aPeterson, B1 aVincent, Warwick, F.1 aLaybourn-Parry, Johanna uhttps://mcm.lternet.edu/content/high-latitude-rivers-and-streams00481nas a2200145 4500008004100000245003600041210003500077260003600112100001500148700002700163700002400190700002500214700002800239856006800267 2008 eng d00aIce-based freshwater ecosystems0 aIcebased freshwater ecosystems aOxfordbOxford University Press1 aHawes, Ian1 aHoward-Williams, Clive1 aFountain, Andrew, G1 aVincent, Warwick, F.1 aLaybourn-Parry, Johanna uhttps://mcm.lternet.edu/content/ice-based-freshwater-ecosystems00672nas a2200193 4500008004100000245008200041210006900123300001400192490000700206100002500213700002500238700002400263700001700287700001600304700001600320700002100336700001700357856010400374 2008 eng d00aInland diatoms from the McMurdo Dry Valleys and James Ross Island, Antarctica0 aInland diatoms from the McMurdo Dry Valleys and James Ross Islan a1378-13920 v121 aEsposito, Rhea, M.M.1 aSpaulding, Sarah, A.1 aMcKnight, Diane, M.1 aDe Vijver, B1 aKopalova, K1 aLubinski, D1 aHall, Brenda, L.1 aWhittaker, T uhttps://mcm.lternet.edu/content/inland-diatoms-mcmurdo-dry-valleys-and-james-ross-island-antarctica00397nas a2200121 4500008004100000245005100041210005100092300001400143490000700157100001600164700001700180856007800197 2008 eng d00aMercury Deposition in a Polar Desert Ecosystem0 aMercury Deposition in a Polar Desert Ecosystem a4710-47160 v421 aWitherow, R1 aLyons, Berry uhttps://mcm.lternet.edu/content/mercury-deposition-polar-desert-ecosystem00528nas a2200145 4500008004100000245005900041210005900100260003600159100001500195700002100210700001700231700002500248700002800273856008100301 2008 eng d00aOrigin and geomorphology of lakes in the polar regions0 aOrigin and geomorphology of lakes in the polar regions aOxfordbOxford University Press1 aPienitz, R1 aDoran, Peter, T.1 aLamoureuz, S1 aVincent, Warwick, F.1 aLaybourn-Parry, Johanna uhttps://mcm.lternet.edu/content/origin-and-geomorphology-lakes-polar-regions00949nas a2200349 4500008004100000245005900041210005800100300001400158490000700172100001800179700001300197700001500210700001400225700001500239700001400254700001400268700001600282700003300298700001500331700001900346700001400365700001100379700002200390700001700412700001300429700001500442700001600457700001600473700001400489700001200503856008400515 2008 eng d00aStoichiometry of soil enzyme activity at global scale.0 aStoichiometry of soil enzyme activity at global scale a1252-12640 v111 aSinsabaugh, R1 aGallo, M1 aGartner, T1 aHobbie, S1 aHolland, K1 aKeeler, B1 aPowers, J1 aStursova, M1 aTakacs-Vesbach, Cristina, D.1 aWaldrop, M1 aWallenstein, M1 aLauber, M1 aZak, D1 aZeglin, Lydia, H.1 aWeintraub, M1 aAhmed, B1 aAllison, S1 aCrenshaw, C1 aContosta, A1 aCusack, D1 aFrey, S uhttps://mcm.lternet.edu/content/stoichiometry-soil-enzyme-activity-global-scale00658nas a2200181 4500008004100000245013600041210006900177300001400246490000700260100002100267700002500288700001900313700002400332700002000356700002500376700001700401856005800418 2008 eng d00aSupersaturated N2O in a perennially ice-covered Antarctic lake: Molecular and stable isotopic evidence for a biogeochemical relict.0 aSupersaturated N2O in a perennially icecovered Antarctic lake Mo a2439-24500 v531 aPriscu, John, C.1 aChristner, Brent, C.1 aDore, John, E.1 aWestley, Marian, B.1 aPopp, Brian, N.1 aCasciotti, Karen, L.1 aLyons, Berry uhttp://brent.xner.net/pdf/Priscu_etal2008_ELB-N2O.pdf00503nas a2200121 4500008004100000245009100041210006900132490000800201100001500209700002400224700001400248856011900262 2008 eng d00aSurface energy balance and melt thresholds over 11 years at Taylor Glacier, Antarctica0 aSurface energy balance and melt thresholds over 11 years at Tayl0 v1131 aHoffman, M1 aFountain, Andrew, G1 aListon, G uhttps://mcm.lternet.edu/content/surface-energy-balance-and-melt-thresholds-over-11-years-taylor-glacier-antarctica00637nas a2200169 4500008004100000245009400041210006900135300001100204490000800215100002300223700002000246700002400266700002400290700002400314700001700338856011200355 2007 eng d00aThe biogeochemical evolution of cryoconite holes on glaciers in Taylor Valley, Antarctica0 abiogeochemical evolution of cryoconite holes on glaciers in Tayl aG04S350 v1131 aBagshaw, Elizabeth1 aTranter, Martyn1 aFountain, Andrew, G1 aWelch, Kathleen, A.1 aBasagic, Hassan, J.1 aLyons, Berry uhttps://mcm.lternet.edu/content/biogeochemical-evolution-cryoconite-holes-glaciers-taylor-valley-antarctica03147nas a2200241 4500008004100000245006800041210006800109260001200177300001400189490000800203520239000211653001102601100002202612700002302634700001702657700002402674700002102698700002402719700002002743700002402763700002102787856009702808 2007 eng d00aBiogeochemical stoichiometry of Antarctic Dry Valley ecosystems0 aBiogeochemical stoichiometry of Antarctic Dry Valley ecosystems c02/2007 aG01010+120 v1123 a

Among aquatic and terrestrial landscapes of the McMurdo Dry Valleys, Antarctica, ecosystem stoichiometry ranges from values near the Redfield ratios for C:N:P to nutrient concentrations in proportions far above or below ratios necessary to support balanced microbial growth. This polar desert provides an opportunity to evaluate stoichiometric approaches to understand nutrient cycling in an ecosystem where biological diversity and activity are low, and controls over the movement and mass balances of nutrients operate over 10–106 years. The simple organisms (microbial and metazoan) comprising dry valley foodwebs adhere to strict biochemical requirements in the composition of their biomass, and when activated by availability of liquid water, they influence the chemical composition of their environment according to these ratios. Nitrogen and phosphorus varied significantly in terrestrial and aquatic ecosystems occurring on landscape surfaces across a wide range of exposure ages, indicating strong influences of landscape development and geochemistry on nutrient availability. Biota control the elemental ratio of stream waters, while geochemical stoichiometry (e.g., weathering, atmospheric deposition) evidently limits the distribution of soil invertebrates. We present a conceptual model describing transformations across dry valley landscapes facilitated by exchanges of liquid water and biotic processing of dissolved nutrients. We conclude that contemporary ecosystem stoichiometry of Antarctic Dry Valley soils, glaciers, streams, and lakes results from a combination of extant biological processes superimposed on a legacy of landscape processes and previous climates.

10aBiggie1 aBarrett, John, E.1 aVirginia, Ross, A.1 aLyons, Berry1 aMcKnight, Diane, M.1 aPriscu, John, C.1 aFountain, Andrew, G1 aWall, Diana, H.1 aMoorhead, Daryl, L.1 aDoran, Peter, T. uhttps://mcm.lternet.edu/content/biogeochemical-stoichiometry-antarctic-dry-valley-ecosystems00393nas a2200121 4500008004100000245004600041210004600087490000700133100001700140700002400157700001500181856007500196 2007 eng d00aOrganic carbon in Antarctic precipitation0 aOrganic carbon in Antarctic precipitation0 v341 aLyons, Berry1 aWelch, Kathleen, A.1 aDoggett, J uhttps://mcm.lternet.edu/content/organic-carbon-antarctic-precipitation00763nas a2200205 4500008004100000245013200041210006900173260001200242300001200254490000700266100002400273700002000297700002400317700002000341700001600361700002400377700001700401700001900418856012000437 2007 eng d00aReactivation of a cryptobiotic stream ecosystem in the McMurdo Dry Valleys, Antarctica: A long-term geomorphological experiment0 aReactivation of a cryptobiotic stream ecosystem in the McMurdo D c09/2007 a186-2040 v891 aMcKnight, Diane, M.1 aTate, Cathy, M.1 aAndrews, Edmund, D.1 aNiyogi, Dev, K.1 aCozzetto, K1 aWelch, Kathleen, A.1 aLyons, Berry1 aCapone, D., G. uhttps://mcm.lternet.edu/content/reactivation-cryptobiotic-stream-ecosystem-mcmurdo-dry-valleys-antarctica-long-term00599nas a2200181 4500008004100000245009400041210006900135260001200204300001200216490000800228653002100236100001400257700002000271700002400291700001700315700002400332856006100356 2007 eng d00aSolute and isotope geochemistry of subsurface ice melt seeps in Taylor Valley, Antarctica0 aSolute and isotope geochemistry of subsurface ice melt seeps in  c01/2007 a548-5550 v11910aClimate Response1 aHarris, K1 aCarey, Anne, E.1 aWelch, Kathleen, A.1 aLyons, Berry1 aFountain, Andrew, G uhttp://gsabulletin.gsapubs.org/content/119/5-6/548.short00704nas a2200169 4500008004100000245010300041210006900144260005400213100002500267700002400292700002100316700001700337700001700354700001900371700002700390856011700417 2007 eng d00aTrends in discharge and flow season timing of the Onyx River, Wright Valley, Antarctica since 19690 aTrends in discharge and flow season timing of the Onyx River Wri bU.S. Geological Survey Open-File Report 2007-10471 aGooseff, Michael, N.1 aMcKnight, Diane, M.1 aDoran, Peter, T.1 aLyons, Berry1 aCooper, Alan1 aRaymond, Carol1 aTeam, ISAES, Editorial uhttps://mcm.lternet.edu/content/trends-discharge-and-flow-season-timing-onyx-river-wright-valley-antarctica-196900754nas a2200205 4500008004100000245012400041210006900165300001200234490000700246100001600253700001500269700002400284700001700308700002300325700001300348700002200361700001500383700002400398856012600422 2006 eng d00aThe aeolian flux of calcium, chloride and nitrate to the McMurdo Dry Valleys landscape: Evidence from snow pit analysis0 aaeolian flux of calcium chloride and nitrate to the McMurdo Dry  a497-5050 v181 aWitherow, R1 aBertler, N1 aWelch, Kathleen, A.1 aLyons, Berry1 aMayewski, Paul, A.1 aSneed, S1 aNylen, Thomas, H.1 aHandley, M1 aFountain, Andrew, G uhttps://mcm.lternet.edu/content/aeolian-flux-calcium-chloride-and-nitrate-mcmurdo-dry-valleys-landscape-evidence-snow-pit00563nas a2200169 4500008004100000245004600041210004600087260003400133100001700167700002800184700002400212700002100236700002000257700001800277700002000295856007800315 2006 eng d00aAntarctic lake systems and climate change0 aAntarctic lake systems and climate change aDordrecht, The NetherlandsbS1 aLyons, Berry1 aLaybourn-Parry, Johanna1 aWelch, Kathleen, A.1 aPriscu, John, C.1 aBergstrom, D.M.1 aConvey, Peter1 aHuiskes, A.H.L. uhttps://mcm.lternet.edu/content/antarctic-lake-systems-and-climate-change00592nas a2200145 4500008004100000245010200041210006900143490000700212100002700219700001600246700001700262700002300279700002100302856012300323 2006 eng d00aMeasuring ecosystem response in a rapidly changing environment: the Latitudinal Gradient Project0 aMeasuring ecosystem response in a rapidly changing environment t0 v101 aHoward-Williams, Clive1 aPeterson, D1 aLyons, Berry1 aCattaneo-Vietti, R1 aGordon, Shulamit uhttps://mcm.lternet.edu/content/measuring-ecosystem-response-rapidly-changing-environment-latitudinal-gradient-project00612nas a2200145 4500008004100000245011000041210006900151260003400220300001100254100001300265700001700278700002200295700002300317856012600340 2006 eng d00aPedogenic carbonate distribution within glacial till in Taylor Valley, Southern Victoria Land, Antarctica0 aPedogenic carbonate distribution within glacial till in Taylor V bGeological Society of America a89-1031 aFoley, K1 aLyons, Berry1 aBarrett, John, E.1 aVirginia, Ross, A. uhttps://mcm.lternet.edu/content/pedogenic-carbonate-distribution-within-glacial-till-taylor-valley-southern-victoria-land00487nas a2200109 4500008004100000245009400041210006900135260003000204100001400234700001700248856011200265 2006 eng d00aA Qualitative Approach to Understanding the Rate of Weathering, Taylor Valley, Antarctica0 aQualitative Approach to Understanding the Rate of Weathering Tay bThe Ohio State University1 aMiller, E1 aLyons, Berry uhttps://mcm.lternet.edu/content/qualitative-approach-understanding-rate-weathering-taylor-valley-antarctica00583nas a2200157 4500008004100000245008700041210006900128300001200197490000700209100002200216700002300238700002200261700002000283700001000303856011200313 2006 eng d00aSalt tolerance and survival thresholds for two species of Antarctic soil nematodes0 aSalt tolerance and survival thresholds for two species of Antarc a643-6510 v291 aNkem, Johnson, N.1 aVirginia, Ross, A.1 aBarrett, John, E.1 aWall, Diana, H.1 aLi, G uhttps://mcm.lternet.edu/content/salt-tolerance-and-survival-thresholds-two-species-antarctic-soil-nematodes00556nas a2200145 4500008004100000245008200041210006900123300001200192490000800204100001500212700002400227700002300251700002800274856010800302 2006 eng d00aSimulating energy flow through a pelagic food web in Lake Fryxell, Antarctica0 aSimulating energy flow through a pelagic food web in Lake Fryxel a457-4720 v1921 aMcKenna, K1 aMoorhead, Daryl, L.1 aRoberts, Emily, C.1 aLaybourn-Parry, Johanna uhttps://mcm.lternet.edu/content/simulating-energy-flow-through-pelagic-food-web-lake-fryxell-antarctica00687nas a2200181 4500008004100000245010500041210006900146260001200215300001000227490000700237100002500244700001700269700002400286700002200310700002400332700002100356856012800377 2006 eng d00aA stable isotopic investigation of a polar desert hydrologic system, McMurdo Dry Valleys, Antarctica0 astable isotopic investigation of a polar desert hydrologic syste c02/2006 a60-710 v381 aGooseff, Michael, N.1 aLyons, Berry1 aMcKnight, Diane, M.1 aVaughn, Bruce, H.1 aFountain, Andrew, G1 aDowling, Carolyn uhttps://mcm.lternet.edu/content/stable-isotopic-investigation-polar-desert-hydrologic-system-mcmurdo-dry-valleys-antarctica00812nas a2200265 4500008004100000245006500041210006400106300001400170490000700184100002200191700002200213700001500235700001600250700002000266700001900286700002300305700002000328700001600348700001600364700001600380700001600396700001700412700002400429856009300453 2006 eng d00aTerrestrial ecosystem processes of Victoria Land, Antarctica0 aTerrestrial ecosystem processes of Victoria Land Antarctica a3019-30340 v381 aBarrett, John, E.1 aNkem, Johnson, N.1 aSletten, R1 aSteltzer, H1 aWall, Diana, H.1 aWallenstein, M1 aVirginia, Ross, A.1 aHopkins, D., W.1 aAislabie, J1 aBargagli, R1 aBockheim, J1 aCampbell, I1 aLyons, Berry1 aMoorhead, Daryl, L. uhttps://mcm.lternet.edu/content/terrestrial-ecosystem-processes-victoria-land-antarctica00648nas a2200157 4500008004100000245012800041210006900169300001000238490000700248100002000255700002400275700001700299700002200316700002400338856012800362 2005 eng d00aThe chemical composition of runoff from Canada Glacier, Antarctica: implications for glacier hydrology during a cool summer0 achemical composition of runoff from Canada Glacier Antarctica im a15-190 v401 aTranter, Martyn1 aFountain, Andrew, G1 aLyons, Berry1 aNylen, Thomas, H.1 aWelch, Kathleen, A. uhttps://mcm.lternet.edu/content/chemical-composition-runoff-canada-glacier-antarctica-implications-glacier-hydrology-during00884nas a2200265 4500008004100000245007800041210007000119300001100189490000700200653002500207100002100232700001900253700002700272700002700299700002400326700002100350700001700371700001300388700002400401700002400425700002400449700002300473700002000496856010200516 2005 eng d00aComment on ``El Niño suppresses Antarctic warming'' by N. Bertler et al.0 aComment on El Niño suppresses Antarctic warming by N Bertler et  aL077060 v3210aTropical meteorology1 aDoran, Peter, T.1 aClow, Gary, D.1 aFritsen, Christian, H.1 aMcKay, Christopher, P.1 aParsons, Andrew, N.1 aPriscu, John, C.1 aLyons, Berry1 aWalsh, J1 aFountain, Andrew, G1 aMcKnight, Diane, M.1 aMoorhead, Daryl, L.1 aVirginia, Ross, A.1 aWall, Diana, H. uhttps://mcm.lternet.edu/content/comment-el-ni%C3%B1o-suppresses-antarctic-warming-n-bertler-et-al00618nas a2200181 4500008004100000245006900041210006800110300000900178490000700187100001700194700002100211700002400232700001400256700002300270700002100293700002400314856009800338 2005 eng d00aDating water and solute additions to ice-covered Antarctic lakes0 aDating water and solute additions to icecovered Antarctic lakes aA7200 v691 aLyons, Berry1 aDowling, Carolyn1 aWelch, Kathleen, A.1 aSnyder, G1 aPoreda, Robert, J.1 aDoran, Peter, T.1 aFountain, Andrew, G uhttps://mcm.lternet.edu/content/dating-water-and-solute-additions-ice-covered-antarctic-lakes00646nas a2200157 4500008004100000245013500041210006900176300001200245490000700257100001900264700002000283700002400303700001700327700002400344856012000368 2005 eng d00aThe Geochemistry of Supraglacial Streams of Canada Glacier, Taylor Valley (Antarctica), and their Evolution into Proglacial Waters0 aGeochemistry of Supraglacial Streams of Canada Glacier Taylor Va a391-4120 v111 aFortner, Sarah1 aTranter, Martyn1 aFountain, Andrew, G1 aLyons, Berry1 aWelch, Kathleen, A. uhttps://mcm.lternet.edu/content/geochemistry-supraglacial-streams-canada-glacier-taylor-valley-antarctica-and-their00711nas a2200205 4500008004100000245008900041210006900130300001200199490000700211100001700218700002400235700002000259700002000279700002300299700002400322700002100346700001400367700001500381856010900396 2005 eng d00aGroundwater seeps in Taylor Valley Antarctica: An example of a subsurface melt event0 aGroundwater seeps in Taylor Valley Antarctica An example of a su a200-2060 v401 aLyons, Berry1 aWelch, Kathleen, A.1 aCarey, Anne, E.1 aWall, Diana, H.1 aVirginia, Ross, A.1 aFountain, Andrew, G1 aDoran, Peter, T.1 aCsatho, B1 aTremper, C uhttps://mcm.lternet.edu/content/groundwater-seeps-taylor-valley-antarctica-example-subsurface-melt-event00681nas a2200181 4500008004100000245012100041210006900162300001200231490000700243100001700250700002400267700001400291700001400305700001400319700001900333700002300352856012400375 2005 eng d00aHalogen geochemistry of the McMurdo Dry Valleys Lakes, Antarctica: clues to the origin of solutes and lake evolution0 aHalogen geochemistry of the McMurdo Dry Valleys Lakes Antarctica a305-3230 v691 aLyons, Berry1 aWelch, Kathleen, A.1 aSnyder, G1 aOlesik, J1 aGraham, E1 aMarion, G., M.1 aPoreda, Robert, J. uhttps://mcm.lternet.edu/content/halogen-geochemistry-mcmurdo-dry-valleys-lakes-antarctica-clues-origin-solutes-and-lake00443nas a2200121 4500008004100000245005800041210005800099260003600157490001000193100001400203700002100217856008300238 2005 eng d00aLacustrine Biogeochemistry of the McMurdo Dry Valleys0 aLacustrine Biogeochemistry of the McMurdo Dry Valleys bUniversity of Illinois, Chicago0 vPh.D.1 aLawson, J1 aDoran, Peter, T. uhttps://mcm.lternet.edu/content/lacustrine-biogeochemistry-mcmurdo-dry-valleys02329nas a2200181 4500008004100000245009400041210006900135260004900204300000800253490000900261520166100270100002201931700001701953700002001970700002001990700002702010856011002037 2005 eng d00aMathematical Modeling of a Hydrocarbon Spill on the Ice Cover of Lake Fryxell, Antarctica0 aMathematical Modeling of a Hydrocarbon Spill on the Ice Cover of aColumbusbThe Ohio State Universityc06/2005 a1140 vM.S.3 a

Numerous perennially ice-covered lakes exist in the McMurdo Dry Valleys region of Antarctica. Ice cover melting on these lakes and meltwater infiltration are important processes affecting the ecology of these lakes. The three lakes in Taylor Valley, Lakes Bonney, Fryxell and Hoare, have been investigated since 1993 as part of the McMurdo Dry Valleys Long Term Ecological Research (MCM LTER) site. A Bell 212 helicopter flying in support of the National Science Foundation's Antarctic Research Program crashed on the frozen surface of Lake Fryxell on January 17, 2003. This resulted in the release of approximately 731 Liters (193 gallons) of diesel fuel and amounts of engine oil and hydraulic fluid. Two physically based models are developed that simulate heat, meltwater flow and solute transport. The first is a transient, one-dimensional, thermodynamic model, which can predict the temperature distribution in the ice cover, melting rate at the surface and at the bottom of ice cover, and ice thickness. The second model simulates unsaturated flow and solute transport and is used to estimate water content distribution and solute transport through the ice cover. The validation of heat transport model was accomplished by comparing model results with the original measurements of ice temperature at various depth in Lake Fryxell. Because of lack of the field data, validation of the unsaturated flow and solute transport model couldn't been accomplished, instead of model validation, programming code has been verified by comparing results with results generated by the HYDRUS 1D software, developed by U.S. Salinity Laboratory, USDA.

1 aKarnovic, Marinko1 aLyons, Berry1 aCarey, Anne, E.1 aBair, Scott, E.1 avan der Veen, Cornelis uhttps://mcm.lternet.edu/content/mathematical-modeling-hydrocarbon-spill-ice-cover-lake-fryxell-antarctica00509nas a2200121 4500008004100000245009200041210006900133260003000202490000900232100001600241700001700257856011300274 2005 eng d00aMercury Concentrations in Snow and the Modern Mercury Flux to Taylor Valley, Antarctica0 aMercury Concentrations in Snow and the Modern Mercury Flux to Ta bThe Ohio State University0 vM.S.1 aWitherow, R1 aLyons, Berry uhttps://mcm.lternet.edu/content/mercury-concentrations-snow-and-modern-mercury-flux-taylor-valley-antarctica00539nas a2200121 4500008004100000245011000041210006900151260003000220490000900250100001300259700001700272856012800289 2005 eng d00aPedogenic Carbonate Distribution within Glacial Till in Taylor Valley, Southern Victoria Land, Antarctica0 aPedogenic Carbonate Distribution within Glacial Till in Taylor V bThe Ohio State University0 vM.S.1 aFoley, K1 aLyons, Berry uhttps://mcm.lternet.edu/content/pedogenic-carbonate-distribution-within-glacial-till-taylor-valley-southern-victoria-land-000755nas a2200217 4500008004100000245008700041210006900128260003100197300001000228100002100238700002200259700002000281700002700301700001900328700002000347700002000367700002200387700001900409700001700428856009200445 2005 eng d00aPerennial Antarctic lake ice: A refuge for cyanobacteria in an extreme environment0 aPerennial Antarctic lake ice A refuge for cyanobacteria in an ex bPrinceton University Press a22-491 aPriscu, John, C.1 aAdams, Edward, E.1 aPaerl, Hans, W.1 aFritsen, Christian, H.1 aDore, John, E.1 aLisle, John, T.1 aWolf, Craig, F.1 aMikucki, Jill, A.1 aRogers, S., O.1 aCastello, J. uhttp://www.montana.edu/lkbonney/DOCS/Publications/PriscuEtAl2005CyanobacteriaRefuge.pdf00677nas a2200181 4500008004100000245009700041210006900138300001000207490000600217100002000223700002400243700002700267700001700294700002100311700001600332700002400348856012300372 2005 eng d00aPerturbation of hydrochemical conditions in natural microcosms entombed within Antarctic ice0 aPerturbation of hydrochemical conditions in natural microcosms e a22-230 v61 aTranter, Martyn1 aFountain, Andrew, G1 aFritsen, Christian, H.1 aLyons, Berry1 aPriscu, John, C.1 aStratham, P1 aWelch, Kathleen, A. uhttps://mcm.lternet.edu/content/perturbation-hydrochemical-conditions-natural-microcosms-entombed-within-antarctic-ice00642nas a2200145 4500008004100000245014700041210006900188490000700257100001900264700001700283700002100300700002500321700002400346856012600370 2004 eng d00aThe Carbon Isotopic Composition of Dissolved Inorganic Carbon in Perennially Ice-Covered Antarctica Lakes: Searching for a Biogenic Signature.0 aCarbon Isotopic Composition of Dissolved Inorganic Carbon in Per0 v391 aNeumann, Klaus1 aLyons, Berry1 aPriscu, John, C.1 aDesMarais, David, J.1 aWelch, Kathleen, A. uhttps://mcm.lternet.edu/content/carbon-isotopic-composition-dissolved-inorganic-carbon-perennially-ice-covered-antarctica00572nas a2200157 4500008004100000245008100041210006900122300001000191490000700201100002400208700002000232700002200252700001300274700002100287856010600308 2004 eng d00aCryoconite holes on polar glaciers and their importance for meltwater runoff0 aCryoconite holes on polar glaciers and their importance for melt a25-450 v501 aFountain, Andrew, G1 aTranter, Martyn1 aNylen, Thomas, H.1 aBooth, D1 aLewis, Karen, J. uhttps://mcm.lternet.edu/content/cryoconite-holes-polar-glaciers-and-their-importance-meltwater-runoff00670nas a2200157 4500008004100000245014600041210006900187300001200256490000700268100002300275700002100298700002000319700001700339700002800356856012800384 2004 eng d00aThe distribution of microplankton in the McMurdo dry valley lakes, Antarctica: Response to ecosystem legacy or present-day climate controls?0 adistribution of microplankton in the McMurdo dry valley lakes An a238-2490 v271 aRoberts, Emily, C.1 aPriscu, John, C.1 aWolf, Craig, F.1 aLyons, Berry1 aLaybourn-Parry, Johanna uhttps://mcm.lternet.edu/content/distribution-microplankton-mcmurdo-dry-valley-lakes-antarctica-response-ecosystem-legacy-or00627nas a2200169 4500008004100000245010400041210006900145300001400214490000700228100001100235700002100246700001900267700001500286700001500301700001400316856012700330 2004 eng d00aElevated levels of dimethylated-sulfur compounds in Lake Bonney, a poorly ventilated Antarctic lake0 aElevated levels of dimethylatedsulfur compounds in Lake Bonney a a1044-10550 v491 aLee, P1 aPriscu, John, C.1 aDiTullio, G, R1 aRiseman, S1 aTursich, N1 aDeMora, S uhttps://mcm.lternet.edu/content/elevated-levels-dimethylated-sulfur-compounds-lake-bonney-poorly-ventilated-antarctic-lake00673nas a2200169 4500008004100000245013000041210006900171260001200240300001000252490000700262100002400269700002000293700002200313700002100335700002300356856012400379 2004 eng d00aEvolution of cryoconite holes and their contribution to meltwater runoff from glaciers in the McMurdo Dry Valleys, Antarctica0 aEvolution of cryoconite holes and their contribution to meltwate c01/2004 a35-450 v501 aFountain, Andrew, G1 aTranter, Martyn1 aNylen, Thomas, H.1 aLewis, Karen, J.1 aMueller, Derek, R. uhttps://mcm.lternet.edu/content/evolution-cryoconite-holes-and-their-contribution-meltwater-runoff-glaciers-mcmurdo-dry00667nas a2200181 4500008004100000245009000041210006900131300001200200490000700212100002000219700002400239700002700263700001700290700002100307700001500328700002400343856011800367 2004 eng d00aExtreme hydrochemical conditions in natural microcosms entombed within Antarctic ice.0 aExtreme hydrochemical conditions in natural microcosms entombed  a379-3870 v181 aTranter, Martyn1 aFountain, Andrew, G1 aFritsen, Christian, H.1 aLyons, Berry1 aPriscu, John, C.1 aStathan, P1 aWelch, Kathleen, A. uhttps://mcm.lternet.edu/content/extreme-hydrochemical-conditions-natural-microcosms-entombed-within-antarctic-ice00629nas a2200157 4500008004100000245011500041210006900156300001200225490000700237100002200244700002700266700001500293700001700308700002100325856012500346 2004 eng d00aGeomicrobiology of Blood Fall: An iron-rich saline discharge at the terminus of the Taylor Glacier, Antarctica0 aGeomicrobiology of Blood Fall An ironrich saline discharge at th a199-2000 v101 aMikucki, Jill, A.1 aForeman, Christine, M.1 aSattler, B1 aLyons, Berry1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/geomicrobiology-blood-fall-iron-rich-saline-discharge-terminus-taylor-glacier-antarctica00667nas a2200169 4500008004100000245013500041210006900176300001400245490000700259100001400266700001600280700001700296700002100313700001100334700002400345856012800369 2004 eng d00aIdentification of a psychrophilic green alga from Lake Bonney, Antarctica: Chlamydomonas raudensis ETTL. (UWO 241) (Chlorophyceae)0 aIdentification of a psychrophilic green alga from Lake Bonney An a1138-11480 v401 aPocock, T1 aLachance, M1 aProschold, T1 aPriscu, John, C.1 aKim, S1 aHuner, Norman, P.A. uhttps://mcm.lternet.edu/content/identification-psychrophilic-green-alga-lake-bonney-antarctica-chlamydomonas-raudensis-ettl00526nas a2200133 4500008004100000245008200041210006900123300001200192490000700204100002300211700002100234700002800255856010900283 2004 eng d00aMicroplankton dynamics in a perennially ice-covered Antarctic lake-Lake Hoare0 aMicroplankton dynamics in a perennially icecovered Antarctic lak a238-2490 v271 aRoberts, Emily, C.1 aPriscu, John, C.1 aLaybourn-Parry, Johanna uhttps://mcm.lternet.edu/content/microplankton-dynamics-perennially-ice-covered-antarctic-lake-lake-hoare00538nas a2200121 4500008004100000245011800041210006900159300001200228490000700240100002000247700002100267856012800288 2004 eng d00aThe Occurrence of Lysogenic Bacteria and Microbial Aggregates in the Lakes of the McMurdo Dry Valleys, Antarctica0 aOccurrence of Lysogenic Bacteria and Microbial Aggregates in the a427-4390 v471 aLisle, John, T.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/occurrence-lysogenic-bacteria-and-microbial-aggregates-lakes-mcmurdo-dry-valleys-antarctica00791nas a2200217 4500008004100000020002200041245008200063210006900145260005900214300001200273100002100285700002100306700001700327700001400344700002300358700002300381700001500404700002900419700001500448856011000463 2004 eng d a978-1-4020-2125-100aPaleolimnology of extreme cold terrestrial and extraterrestrial environments.0 aPaleolimnology of extreme cold terrestrial and extraterrestrial  aDordrecht, The NetherlandsbKluwer Academic Publishers a475-5071 aDoran, Peter, T.1 aPriscu, John, C.1 aLyons, Berry1 aPowell, R1 aPoreda, Robert, J.1 aAndersen, Dale, T.1 aPienitz, R1 aDouglas, Marianne, S. V.1 aSmol, J.P. uhttps://mcm.lternet.edu/content/paleolimnology-extreme-cold-terrestrial-and-extraterrestrial-environments00602nas a2200193 4500008004100000245004700041210004600088260003100134300001200165100002100177700002100198700001700219700001400236700002300250700001500273700002900288700001500317856007600332 2004 eng d00aPaleolimnology of Ice-covered Environments0 aPaleolimnology of Icecovered Environments bKluwer Academic Publishers a475-5071 aDoran, Peter, T.1 aPriscu, John, C.1 aLyons, Berry1 aPowell, R1 aPoreda, Robert, J.1 aPienitz, R1 aDouglas, Marianne, S. V.1 aSmol, John uhttps://mcm.lternet.edu/content/paleolimnology-ice-covered-environments00661nas a2200157 4500008004100000245015000041210006900191300001200260490000700272100001400279700002100293700001800314700002500332700002100357856012500378 2004 eng d00aStable carbon and nitrogen isotopic compositions of benthic and pelagic organic matter in four polar lakes of the McMurdo Dry Valleys, Antarctica0 aStable carbon and nitrogen isotopic compositions of benthic and  a269-3010 v101 aLawson, J1 aDoran, Peter, T.1 aKenig, Fabien1 aDesMarais, David, J.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/stable-carbon-and-nitrogen-isotopic-compositions-benthic-and-pelagic-organic-matter-four00726nas a2200205 4500008004100000245011200041210006900153300000900222490000700231100001100238700002200249700002700271700002100298700001900319700001500338700001400353700002000367700001400387856011900401 2004 eng d00aThermodynamic constraints on microbially mediated processes in lakes of the McMurdo Dry Valleys, Antarctica0 aThermodynamic constraints on microbially mediated processes in l a1-170 v211 aLee, P1 aMikucki, Jill, A.1 aForeman, Christine, M.1 aPriscu, John, C.1 aDiTullio, G, R1 aRiseman, S1 aDeMora, S1 aWolf, Craig, F.1 aKester, L uhttps://mcm.lternet.edu/content/thermodynamic-constraints-microbially-mediated-processes-lakes-mcmurdo-dry-valleys00957nas a2200301 4500008004100000020001800041245008800059210006900147260001700216300001200233100001400245700001600259700002900275700001400304700001700318700002600335700001800361700001500379700001500394700002200409700002100431700001700452700001800469700001700487700002000504700002000524856011100544 2004 eng d a1-55963-760-900aVulnerability to global change of ecosystem goods and services driven by soil biota0 aVulnerability to global change of ecosystem goods and services d bIsland Press a101-1361 aWardle, D1 aBrown, V.K.1 aBehan-Pelletier, Valerie1 aJohn, St.1 aWojtowicz, T1 aBardgett, Richard, D.1 aBrown, G., G.1 aIneson, P.1 aLavelle, P1 avan der Putten, W1 aAnderson, J., M.1 aBrussaard, L1 aHunt, William1 aPaul, E., A.1 aWall, Diana, H.1 aWall, Diana, H. uhttps://mcm.lternet.edu/content/vulnerability-global-change-ecosystem-goods-and-services-driven-soil-biota00536nas a2200157 4500008004100000245006700041210006600108300001200174490000600186100001200192700002400204700001700228700002100245700002400266856008800290 2003 eng d00aBiochemistry of Si in the McMurdo Dry Valley lakes, Antarctica0 aBiochemistry of Si in the McMurdo Dry Valley lakes Antarctica a737-7490 v11 aPugh, H1 aWelch, Kathleen, A.1 aLyons, Berry1 aPriscu, John, C.1 aMcKnight, Diane, M. uhttps://mcm.lternet.edu/content/biochemistry-si-mcmurdo-dry-valley-lakes-antarctica00702nas a2200181 4500008004100000020001500041245009900056210006900155260004300224300001200267653002100279100002400300700001700324700001800341700001900359700001800378856012400396 2003 eng d a019515059700aCentury to millennial scale climate change and ecosystem response in Taylor Valley, Antarctica0 aCentury to millennial scale climate change and ecosystem respons aNew York CitybOxford University Press a319-34010aClimate Response1 aFountain, Andrew, G1 aLyons, Berry1 aGreenland, D.1 aGoodin, D., G.1 aSmith, R., C. uhttps://mcm.lternet.edu/content/century-millennial-scale-climate-change-and-ecosystem-response-taylor-valley-antarctica00679nas a2200169 4500008004100000245011200041210006900153260001700222100002400239700001900263700001700282700002400299700002700323700001700350700001500367856012700382 2003 eng d00aChemistry and lake dynamics of the Taylor Valley lakes, Antarctica: The importance of long-term monitoring.0 aChemistry and lake dynamics of the Taylor Valley lakes Antarctic bCaxton Press1 aWelch, Kathleen, A.1 aNeumann, Klaus1 aLyons, Berry1 aMcKnight, Diane, M.1 aHoward-Williams, Clive1 aDavidson, W.1 aBroady, P. uhttps://mcm.lternet.edu/content/chemistry-and-lake-dynamics-taylor-valley-lakes-antarctica-importance-long-term-monitoring00733nas a2200193 4500008004100000245014900041210006900190300001200259490000600271100001500277700002100292700001900313700001400332700001400346700001900360700001500379700002100394856012400415 2003 eng d00aFourier-transform raman spectroscopic studies of organic and inorganic chemical components in stromatolitic cores from Antarctic lake sediments0 aFouriertransform raman spectroscopic studies of organic and inor a325-3310 v11 aEdwards, H1 aWynn-Williams, D1 aEllis-Evans, J1 aNewton, E1 aLittle, S1 ade Oliveira, L1 aHodgson, D1 aDoran, Peter, T. uhttps://mcm.lternet.edu/content/fourier-transform-raman-spectroscopic-studies-organic-and-inorganic-chemical-components00548nas a2200145 4500008004100000245009000041210006900131300000900200490000800209100002100217700002400238700001400262700001600276856011000292 2003 eng d00aGlaciers of the McMurdo Dry Valleys: terrestrial analog for Martian polar sublimation0 aGlaciers of the McMurdo Dry Valleys terrestrial analog for Marti a50310 v1081 aLewis, Karen, J.1 aFountain, Andrew, G1 aKargel, J1 aMacAyeal, D uhttps://mcm.lternet.edu/content/glaciers-mcmurdo-dry-valleys-terrestrial-analog-martian-polar-sublimation00462nas a2200121 4500008004100000245007200041210006900113300001200182490000700194100001500201700002400216856010000240 2003 eng d00aMap-based methods for estimating glacier equilibrium-line altitudes0 aMapbased methods for estimating glacier equilibriumline altitude a329-3360 v491 aLeonard, K1 aFountain, Andrew, G uhttps://mcm.lternet.edu/content/map-based-methods-estimating-glacier-equilibrium-line-altitudes00570nas a2200121 4500008004100000245013800041210006900179260003000248490000900278100001500287700001700302856012900319 2003 eng d00aPhosphorus in Taylor Valley, Antarctica: the connection between landscape age and nutrient limitation in aquatic ecosystem components0 aPhosphorus in Taylor Valley Antarctica the connection between la bThe Ohio State University0 vM.S.1 aGudding, J1 aLyons, Berry uhttps://mcm.lternet.edu/content/phosphorus-taylor-valley-antarctica-connection-between-landscape-age-and-nutrient-limitation00478nas a2200085 4500008004100000245012900041210006900170100002800239856012500267 2003 eng d00aPolar Limnology - the past, the present, and the future. Review in the SCAR VIII International Biology Symposium Proceedings0 aPolar Limnology the past the present and the future Review in th1 aLaybourn-Parry, Johanna uhttps://mcm.lternet.edu/content/polar-limnology-past-present-and-future-review-scar-viii-international-biology-symposium00722nas a2200193 4500008004100000245015200041210006900193300001200262490000600274100001700280700001800297700001400315700001400329700001400343700001200357700002400369700001400393856012100407 2003 eng d00aStrontium isotopic signatures of the streams and lakes of Taylor Valley, southern Victoria Land, Antarctica: chemical weathering in a polar climate0 aStrontium isotopic signatures of the streams and lakes of Taylor a875-8950 v81 aLyons, Berry1 aNezat, C., A.1 aBenson, L1 aBullen, T1 aGraham, E1 aKidd, J1 aWelch, Kathleen, A.1 aThomas, J uhttps://mcm.lternet.edu/content/strontium-isotopic-signatures-streams-and-lakes-taylor-valley-southern-victoria-land00682nas a2200169 4500008004100000245012300041210006900164300001200233490000700245100001700252700002400269700002400293700002000317700002200337700002400359856012900383 2003 eng d00aSurface glaciochemistry of Taylor Valley, southern Victoria Land, Antarctica and its relationship to stream chemistry.0 aSurface glaciochemistry of Taylor Valley southern Victoria Land  a115-1300 v171 aLyons, Berry1 aWelch, Kathleen, A.1 aFountain, Andrew, G1 aDana, Gayle, L.1 aVaughn, Bruce, H.1 aMcKnight, Diane, M. uhttps://mcm.lternet.edu/content/surface-glaciochemistry-taylor-valley-southern-victoria-land-antarctica-and-its-relationship00890nas a2200277 4500008004100000245006500041210006500106260001200171300001200183490000800195653002100203100002100224700002100245700001700266700002000283700002400303700002400327700002400351700002300375700002000398700001900418700002700437700002700464700002400491856009700515 2002 eng d00aAntarctic climate cooling and terrestrial ecosystem response0 aAntarctic climate cooling and terrestrial ecosystem response c01/2002 a517-5200 v41510aClimate Response1 aDoran, Peter, T.1 aPriscu, John, C.1 aLyons, Berry1 aWalsh, John, E.1 aFountain, Andrew, G1 aMcKnight, Diane, M.1 aMoorhead, Daryl, L.1 aVirginia, Ross, A.1 aWall, Diana, H.1 aClow, Gary, D.1 aFritsen, Christian, H.1 aMcKay, Christopher, P.1 aParsons, Andrew, N. uhttps://mcm.lternet.edu/content/antarctic-climate-cooling-and-terrestrial-ecosystem-response00529nas a2200121 4500008004100000245010400041210006900145300001400214490000700228100001600235700002800251856012800279 2002 eng d00aThe balance between photosynthesis and grazing in Antarctic mixotrophic cryptophytes during summer0 abalance between photosynthesis and grazing in Antarctic mixotrop a2060-20700 v471 aMarshall, W1 aLaybourn-Parry, Johanna uhttps://mcm.lternet.edu/content/balance-between-photosynthesis-and-grazing-antarctic-mixotrophic-cryptophytes-during-summer00431nas a2200121 4500008004100000245006200041210005800103260003000161490000900191100001200200700001700212856008000229 2002 eng d00aThe biogeochemistry of Si in the McMurdo Dry Valley Lakes0 abiogeochemistry of Si in the McMurdo Dry Valley Lakes bThe Ohio State University0 vB.S.1 aPugh, H1 aLyons, Berry uhttps://mcm.lternet.edu/content/biogeochemistry-si-mcmurdo-dry-valley-lakes00539nas a2200121 4500008004100000245011500041210006900156260003000225490000900255100001200264700001700276856012400293 2002 eng d00aThe chemical evolution of Canada Glacier melt: supraglacial and proglacial waters in Taylor Valley, Antarctica0 achemical evolution of Canada Glacier melt supraglacial and progl bThe Ohio State University0 vM.S.1 aTegt, S1 aLyons, Berry uhttps://mcm.lternet.edu/content/chemical-evolution-canada-glacier-melt-supraglacial-and-proglacial-waters-taylor-valley00614nas a2200157 4500008004100000245010900041210006900150300001400219490000700233100001500240700002400255700001200279700001500291700002500306856012500331 2002 eng d00aDirect observation of aluminosilicate weathering in the hyporheic zone of an Antarctic Dry Valley stream0 aDirect observation of aluminosilicate weathering in the hyporhei a1335-13470 v661 aMaurice, P1 aMcKnight, Diane, M.1 aLeff, L1 aFulghun, J1 aGooseff, Michael, N. uhttps://mcm.lternet.edu/content/direct-observation-aluminosilicate-weathering-hyporheic-zone-antarctic-dry-valley-stream00460nas a2200109 4500008004100000245009300041210006900134300001200203490000700215100001700222856011100239 2002 eng d00aFlux of eolian sediment in the Mcmurdo Dry Valleys, Antarctica: a preliminary assessment0 aFlux of eolian sediment in the Mcmurdo Dry Valleys Antarctica a  a318-3230 v341 aLancaster, N uhttps://mcm.lternet.edu/content/flux-eolian-sediment-mcmurdo-dry-valleys-antarctica-preliminary-assessment00772nas a2200253 4500008004100000245004700041210004700088300001200135490000800147100002000155700001900175700002700194700002700221700002400248700002100272700002100293700001700314700002400331700002400355700002400379700002300403700002000426856007200446 2002 eng d00aRecent Temperature Trends in the Antarctic0 aRecent Temperature Trends in the Antarctic a291-2920 v4181 aWalsh, John, E.1 aClow, Gary, D.1 aFritsen, Christian, H.1 aMcKay, Christopher, P.1 aParsons, Andrew, N.1 aDoran, Peter, T.1 aPriscu, John, C.1 aLyons, Berry1 aFountain, Andrew, G1 aMcKnight, Diane, M.1 aMoorhead, Daryl, L.1 aVirginia, Ross, A.1 aWall, Diana, H. uhttps://mcm.lternet.edu/content/recent-temperature-trends-antarctic00760nas a2200229 4500008004100000245012700041210006900168260001200237300001000249490000700259653001100266100002500277700002200302700002100324700002400345700001700369700002400386700001800410700002300428700002000451856005900471 2002 eng d00aSnow patch influence on soil biogeochemical processes and invertebrate distribution in the McMurdo Dry Valleys, Antarctica0 aSnow patch influence on soil biogeochemical processes and invert c02/2003 a91-990 v3510aBiggie1 aGooseff, Michael, N.1 aBarrett, John, E.1 aDoran, Peter, T.1 aFountain, Andrew, G1 aLyons, Berry1 aParsons, Andrew, N.1 aPorazinska, D1 aVirginia, Ross, A.1 aWall, Diana, H. uhttp://instaar.metapress.com/content/r086455ju7213711/00357nas a2200109 4500008004100000245004300041210004300084300001200127490000800139100002800147856007200175 2002 eng d00aSurvival mechanisms in Antarctic lakes0 aSurvival mechanisms in Antarctic lakes a863-8690 v3571 aLaybourn-Parry, Johanna uhttps://mcm.lternet.edu/content/survival-mechanisms-antarctic-lakes03551nas a2200217 4500008004100000245009000041210006900131260001200200300001400212490000800226520282700234653001103061100002103072700002703093700001903120700002003139700002403159700002203183700001703205856011103222 2002 eng d00aValley floor climate observations from the McMurdo Dry Valleys, Antarctica, 1986-20000 aValley floor climate observations from the McMurdo Dry Valleys A c12/2002 a4772-47840 v1073 a

Climate observations from the McMurdo dry valleys, East Antarctica are presented from a network of seven valley floor automatic meteorological stations during the period 1986 to 2000. Mean annual temperatures ranged from −14.8°C to −30.0°C, depending on the site and period of measurement. Mean annual relative humidity is generally highest near the coast. Mean annual wind speed increases with proximity to the polar plateau. Site-to-site variation in mean annual solar flux and PAR is due to exposure of each station and changes over time are likely related to changes in cloudiness. During the nonsummer months, strong katabatic winds are frequent at some sites and infrequent at others, creating large variation in mean annual temperature owing to the warming effect of the winds. Katabatic wind exposure appears to be controlled to a large degree by the presence of colder air in the region that collects at low points and keeps the warm less dense katabatic flow from the ground. The strong influence of katabatic winds makes prediction of relative mean annual temperature based on geographical position (elevation and distance from the coast) alone, not possible. During the summer months, onshore winds dominate and warm as they progress through the valleys creating a strong linear relationship (r2 = 0.992) of increasing potential temperature with distance from the coast (0.09°C km−1). In contrast to mean annual temperature, summer temperature lends itself quite well to model predictions, and is used to construct a statistical model for predicting summer dry valley temperatures at unmonitored sites.

10aBiggie1 aDoran, Peter, T.1 aMcKay, Christopher, P.1 aClow, Gary, D.1 aDana, Gayle, L.1 aFountain, Andrew, G1 aNylen, Thomas, H.1 aLyons, Berry uhttps://mcm.lternet.edu/content/valley-floor-climate-observations-mcmurdo-dry-valleys-antarctica-1986-200000603nas a2200169 4500008004100000245014000041210006900181260001200250300001400262490000700276653001100283100002500294700002400319700001700343700001200360856006100372 2002 eng d00aWeathering reactions and hyporheic exchange controls on stream water chemistry in a glacial meltwater stream in the McMurdo Dry Valleys0 aWeathering reactions and hyporheic exchange controls on stream w c12/2002 a1279-12960 v3810aBiggie1 aGooseff, Michael, N.1 aMcKnight, Diane, M.1 aLyons, Berry1 aBlum, A uhttp://www.agu.org/pubs/crossref/2002/2001WR000834.shtml00448nas a2200145 4500008004100000245004600041210004600087260001900133300001200152490000600164100002300170700002000193700001400213856007500227 2001 eng d00aBasic Principles in ecosystem functioning0 aBasic Principles in ecosystem functioning bAcademic Press a345-3520 v21 aVirginia, Ross, A.1 aWall, Diana, H.1 aLevin, S. uhttps://mcm.lternet.edu/content/basic-principles-ecosystem-functioning00510nas a2200133 4500008004100000245008300041210006900124300001400193490000800207100001800215700001700233700002400250856010200274 2001 eng d00aChemical weathering in streams of a polar desert (Taylor Valley, Antarctica).0 aChemical weathering in streams of a polar desert Taylor Valley A a1401-14080 v1131 aNezat, C., A.1 aLyons, Berry1 aWelch, Kathleen, A. uhttps://mcm.lternet.edu/content/chemical-weathering-streams-polar-desert-taylor-valley-antarctica00540nas a2200145 4500008004100000245008500041210006900126300001000195490000700205100001900212700001700231700002100248700001500269856011000284 2001 eng d00aCO2 concentrations in perennially ice-covered lakes of Taylor Valley, Antarctica0 aCO2 concentrations in perennially icecovered lakes of Taylor Val a27-500 v561 aNeumann, Klaus1 aLyons, Berry1 aPriscu, John, C.1 aDonahoe, R uhttps://mcm.lternet.edu/content/co2-concentrations-perennially-ice-covered-lakes-taylor-valley-antarctica00531nas a2200121 4500008004100000245009500041210006900136260003000205490001000235100002100245700002400266856011900290 2001 eng d00aEnergy balance of a rough glacier surface, Canada Glacier, McMurdo Dry Valleys, Antarctica0 aEnergy balance of a rough glacier surface Canada Glacier McMurdo bPortland State University0 vPh.D.1 aLewis, Karen, J.1 aFountain, Andrew, G uhttps://mcm.lternet.edu/content/energy-balance-rough-glacier-surface-canada-glacier-mcmurdo-dry-valleys-antarctica00774nas a2200193 4500008004100000245014400041210006900185300001200254490000700266100001700273700002400290700002100314700002800335700002400363700002400387700002100411700002000432856012800452 2001 eng d00aThe McMurdo Dry Valleys Long-Term Ecological Research Program: new understanding of the biogeochemistry of the Dry Valley lakes: a review.0 aMcMurdo Dry Valleys LongTerm Ecological Research Program new und a202-2170 v251 aLyons, Berry1 aWelch, Kathleen, A.1 aPriscu, John, C.1 aLaybourn-Parry, Johanna1 aMoorhead, Daryl, L.1 aMcKnight, Diane, M.1 aDoran, Peter, T.1 aTranter, Martyn uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-long-term-ecological-research-program-new-understanding-biogeochemistry00770nas a2200193 4500008004100000245019000041210006900231300001400300490000700314100002300321700001500344700001400359700002100373700001600394700001300410700001500423700001700438856012100455 2001 eng d00aMineralogical and geochemical analyses of Antarctic lake sediments: A study of reflectanceand Mossbauer spectroscopy and C, N and S isotopes with applications for remote sensing on Mars0 aMineralogical and geochemical analyses of Antarctic lake sedimen a2875-28970 v651 aBishop, Janice, L.1 aLougear, A1 aNewton, J1 aDoran, Peter, T.1 aFroeschl, H1 aKrner, W1 aKoeberl, C1 aTrautwein, A uhttps://mcm.lternet.edu/content/mineralogical-and-geochemical-analyses-antarctic-lake-sediments-study-reflectanceand00868nas a2200229 4500008004100000245013400041210006900175260002800244300001200272100002400284700001700308700002400325700001700349700002400366700002200390700002100412700002700433700001800460700001900478700001800497856012300515 2000 eng d00aClimate and hydrologic variations and implications for lake and stream ecological response in the McMurdo Dry Valleys, Antarctica0 aClimate and hydrologic variations and implications for lake and  bOxford University Press a174-1951 aWelch, Kathleen, A.1 aLyons, Berry1 aMcKnight, Diane, M.1 aJaros, Chris1 aFountain, Andrew, G1 aNylen, Thomas, H.1 aDoran, Peter, T.1 aHoward-Williams, Clive1 aGreenland, D.1 aGoodin, D., G.1 aSmith, R., C. uhttps://mcm.lternet.edu/content/climate-and-hydrologic-variations-and-implications-lake-and-stream-ecological-response00674nas a2200157 4500008004100000245016800041210006900209300001400278490000700292100001700299700001800316700002400334700001700358700002100375856012000396 2000 eng d00aFossil fuel burning in Taylor Valley, southern Victoria Land, Antarctica: estimating the role of scientific activities on carbon and nitrogen reservoirs and fluxes0 aFossil fuel burning in Taylor Valley southern Victoria Land Anta a1659-16620 v341 aLyons, Berry1 aNezat, C., A.1 aWelch, Kathleen, A.1 aKottmeier, S1 aDoran, Peter, T. uhttps://mcm.lternet.edu/content/fossil-fuel-burning-taylor-valley-southern-victoria-land-antarctica-estimating-role00870nas a2200325 4500008004100000245005200041210005200093300001400145490000800159100002200167700001400189700001500203700001300218700001400231700001800245700001200263700001300275700001400288700001500302700002000317700001900337700001500356700001400371700001800385700001300403700002100416700001600437700001500453856007600468 2000 eng d00aGlobal biodiversity scenarios for the year 21000 aGlobal biodiversity scenarios for the year 2100 a1770-17740 v2871 aSala, Osvaldo, E.1 aKinzig, A1 aLeemans, R1 aLodge, D1 aMooney, H1 aOesterheld, M1 aPoff, N1 aSykes, M1 aWalker, B1 aWalkder, M1 aWall, Diana, H.1 aChapin, F., S.1 aArmesto, J1 aBerlow, E1 aBloomfield, J1 aDirzo, R1 aHuber-Sanwald, E1 aHuenneke, L1 aJackson, R uhttps://mcm.lternet.edu/content/global-biodiversity-scenarios-year-210001013nas a2200313 4500008004100000245014800041210006900189300001400258490000700272100001500279700001400294700001700308700002200325700001300347700001400360700001400374700002200388700001400410700001600424700001400440700001500454700002300469700001500492700002200507700001600529700001700545700002000562856011700582 2000 eng d00aGlobal change effects on above and below ground biodiversity in terrestrial ecosystems: interactions and implications for ecosystem functioning0 aGlobal change effects on above and below ground biodiversity in  a1089-10990 v501 aWolters, V1 aWardle, D1 aBrussaard, L1 aDangerfield, Mark1 aBrown, V1 aGiller, K1 aHooper, D1 aSala, Osvaldo, E.1 aTiedje, J1 avan Veen, J1 aSilver, W1 aBignell, D1 aColeman, David, C.1 aLavelle, P1 avan der Putten, W1 aDeRuiter, P1 aRusek, Josef1 aWall, Diana, H. uhttps://mcm.lternet.edu/content/global-change-effects-above-and-below-ground-biodiversity-terrestrial-ecosystems00667nas a2200169 4500008004100000245011600041210006900157300001200226490000700238100001700245700002400262700002100286700002100307700001900328700002400347856012600371 2000 eng d00aThe importance of landscape position and legacy: The evolution of the Taylor Valley Lake District, Antarctica.0 aimportance of landscape position and legacy The evolution of the a355-3670 v431 aLyons, Berry1 aFountain, Andrew, G1 aDoran, Peter, T.1 aPriscu, John, C.1 aNeumann, Klaus1 aWelch, Kathleen, A. uhttps://mcm.lternet.edu/content/importance-landscape-position-and-legacy-evolution-taylor-valley-lake-district-antarctica00932nas a2200289 4500008004100000245012200041210006900163300001400232490000700246100001400253700001500267700002200282700001600304700001700320700001400337700001400351700001500365700001500380700001300395700001700408700002200425700002000447700001400467700002300481700001400504856012400518 2000 eng d00aInteractions between above and belowground biodiversity in terrestrial ecosystems: patterns, mechanisms and feedbacks0 aInteractions between above and belowground biodiversity in terre a1049-10610 v501 aHooper, D1 aLavelle, P1 avan der Putten, W1 aDeRuiter, P1 aRusek, Josef1 aSilver, W1 aTiedje, J1 aWolters, V1 aBignell, D1 aBrown, V1 aBrussaard, L1 aDangerfield, Mark1 aWall, Diana, H.1 aWardle, D1 aColeman, David, C.1 aGiller, K uhttps://mcm.lternet.edu/content/interactions-between-above-and-belowground-biodiversity-terrestrial-ecosystems-patterns00606nas a2200157 4500008004100000245008300041210006900124260001700193100002800210700002300238700002100261700002700282700001700309700001500326856010700341 2000 eng d00aMixotrophy as a survival strategy among planktonic protozoa in Antarctic lakes0 aMixotrophy as a survival strategy among planktonic protozoa in A bCaxton Press1 aLaybourn-Parry, Johanna1 aRoberts, Emily, C.1 aBell, Elanor, R.1 aHoward-Williams, Clive1 aDavidson, W.1 aBroady, P. uhttps://mcm.lternet.edu/content/mixotrophy-survival-strategy-among-planktonic-protozoa-antarctic-lakes00433nas a2200133 4500008004100000245004600041210004600087300001200133490000700145100002800152700002100180700002300201856007500224 2000 eng d00aProtozoan growth rates in Antarctic lakes0 aProtozoan growth rates in Antarctic lakes a445-4510 v231 aLaybourn-Parry, Johanna1 aBell, Elanor, R.1 aRoberts, Emily, C. uhttps://mcm.lternet.edu/content/protozoan-growth-rates-antarctic-lakes00594nas a2200193 4500008004100000245004800041210004800089260002500137300001200162100002000174700001600194700001500210700001600225700001600241700001900257700002000276700002400296856008000320 2000 eng d00aSoil Biodiversity and Ecosystem Functioning0 aSoil Biodiversity and Ecosystem Functioning aHeidelbergbSpringer a283-2901 aWall, Diana, H.1 aLynch, J.M.1 aBalazs, E.1 aGalante, E.1 aLynch, J.M.1 aSchepers, J.S.1 aToutant, Werner1 aWerry, P.A., Th. J. uhttps://mcm.lternet.edu/content/soil-biodiversity-and-ecosystem-functioning00374nas a2200145 4500008004100000245002200041210002200063260001900085300001200104490000600116100001800122700002000140700001400160856005400174 2000 eng d00aSoil Conservation0 aSoil Conservation bAcademic Press a315-3260 v51 aPorazinska, D1 aWall, Diana, H.1 aLevin, S. uhttps://mcm.lternet.edu/content/soil-conservation00609nas a2200181 4500008004100000245009000041210006900131260001200200300001200212490000700224653001100231653001300242100002300255700002800278700002400306700001600330856008100346 2000 eng d00aStratification and dynamics of microbial loop communities in Lake Fryxell, Antarctica0 aStratification and dynamics of microbial loop communities in Lak c12/2001 a649-6610 v4410aBiggie10aprotozoa1 aRoberts, Emily, C.1 aLaybourn-Parry, Johanna1 aMcKnight, Diane, M.1 aNovarino, G uhttp://onlinelibrary.wiley.com/doi/10.1046/j.1365-2427.2000.00612.x/abstract00522nas a2200157 4500008004100000245005500041210005300096260003100149300001000180653001100190100002100201700001700222700001800239700002200257856008500279 1999 eng d00aArctic and Antarctic lakes: contrast or continuum?0 aArctic and Antarctic lakes contrast or continuum bUniversity of Ottawa Press a59-6810aBiggie1 aDoran, Peter, T.1 aAdams, Peter1 aEcclestone, M1 aLewkowicz, A., G. uhttps://mcm.lternet.edu/content/arctic-and-antarctic-lakes-contrast-or-continuum00481nas a2200121 4500008004100000245007000041210006900111260003800180490001000218100001900228700001700247856009500264 1999 eng d00aCarbon dynamics in lakes and streams of Taylor Valley, Antarctica0 aCarbon dynamics in lakes and streams of Taylor Valley Antarctica bUniversity of Alabama, Tuscaloosa0 vPh.D.1 aNeumann, Klaus1 aLyons, Berry uhttps://mcm.lternet.edu/content/carbon-dynamics-lakes-and-streams-taylor-valley-antarctica00607nas a2200157 4500008004100000245007100041210006900112100002100181700002000202700003300222700002700255700002800282700002300310700001800333856009800351 1999 eng d00aCarbon transformations in a perennially ice-covered Antarctic lake0 aCarbon transformations in a perennially icecovered Antarctic lak1 aPriscu, John, C.1 aWolf, Craig, F.1 aTakacs-Vesbach, Cristina, D.1 aFritsen, Christian, H.1 aLaybourn-Parry, Johanna1 aRoberts, Emily, C.1 aSattl, Birgit uhttps://mcm.lternet.edu/content/carbon-transformations-perennially-ice-covered-antarctic-lake00557nas a2200133 4500008004100000245011000041210006900151300001200220490000700232100001700239700002400256700001900280856012400299 1999 eng d00aChlorine-36 in the waters of the McMurdo Dry Valley lakes, southern Victoria Land, Antarctica: revisited0 aChlorine36 in the waters of the McMurdo Dry Valley lakes souther a185-1910 v621 aLyons, Berry1 aWelch, Kathleen, A.1 aSharma, Pankaj uhttps://mcm.lternet.edu/content/chlorine-36-waters-mcmurdo-dry-valley-lakes-southern-victoria-land-antarctica-revisited00684nas a2200205 4500008004100000245008100041210006900122260001200191300001200203490000800215653001400223100002100237700001900258700001700277700002400294700002100318700001600339700001700355856010600372 1999 eng d00aDating quaternary lacustrine sediments in the McMurdo Dry Valleys Antarctica0 aDating quaternary lacustrine sediments in the McMurdo Dry Valley c03/1999 a223-2390 v14710asediments1 aDoran, Peter, T.1 aBerger, G., W.1 aLyons, Berry1 aWharton, Robert, A.1 aDavisson, M., L.1 aSouthon, J.1 aDibb, J., E. uhttps://mcm.lternet.edu/content/dating-quaternary-lacustrine-sediments-mcmurdo-dry-valleys-antarctica00781nas a2200241 4500008004100000245006000041210005900101300001400160490000800174100002100182700002200203700001700225700002100242700002000263700002200283700002700305700003300332700002400365700002000389700002500409700001600434856008900450 1999 eng d00aGeomicrobiology of sub-glacial ice above Vostok Station0 aGeomicrobiology of subglacial ice above Vostok Station a2141-21440 v2861 aPriscu, John, C.1 aAdams, Edward, E.1 aLyons, Berry1 aVoytek, Mary, A.1 aMogk, David, W.1 aBrown, Robert, L.1 aMcKay, Christopher, P.1 aTakacs-Vesbach, Cristina, D.1 aWelch, Kathleen, A.1 aWolf, Craig, F.1 aKirshtein, Julie, D.1 aAvci, Recep uhttps://mcm.lternet.edu/content/geomicrobiology-sub-glacial-ice-above-vostok-station00489nas a2200121 4500008004100000245008700041210006900128490000700197100001700204700001300221700002400234856010900258 1999 eng d00aHistory of McMurdo Dry Valley Lakes, Antarctica, from stable chlorine isotope data0 aHistory of McMurdo Dry Valley Lakes Antarctica from stable chlor0 v271 aLyons, Berry1 aFrape, S1 aWelch, Kathleen, A. uhttps://mcm.lternet.edu/content/history-mcmurdo-dry-valley-lakes-antarctica-stable-chlorine-isotope-data00533nas a2200133 4500008004100000245009300041210006900134300001200203490000700215100002100222700002400243700001900267856011300286 1999 eng d00aThe importance of terminus cliff melt on stream flow, Taylor Valley, McMurdo Dry Valleys0 aimportance of terminus cliff melt on stream flow Taylor Valley M a105-1150 v221 aLewis, Karen, J.1 aFountain, Andrew, G1 aLangevin, Paul uhttps://mcm.lternet.edu/content/importance-terminus-cliff-melt-stream-flow-taylor-valley-mcmurdo-dry-valleys00424nas a2200133 4500008004100000245004500041210004500086300001400131490000700145100001700152700002400169700002600193856007100219 1999 eng d00aMercury in aquatic systems in Antarctica0 aMercury in aquatic systems in Antarctica a2235-22380 v261 aLyons, Berry1 aWelch, Kathleen, A.1 aBonzongo, Jean-Claude uhttps://mcm.lternet.edu/content/mercury-aquatic-systems-antarctica00498nas a2200121 4500008004100000245008700041210006900128300001200197490000700209100002300216700002800239856010900267 1999 eng d00aMixotrophic cryptophytes and their predators in the Dry Valley lakes of Antarctica0 aMixotrophic cryptophytes and their predators in the Dry Valley l a737-7450 v411 aRoberts, Emily, C.1 aLaybourn-Parry, Johanna uhttps://mcm.lternet.edu/content/mixotrophic-cryptophytes-and-their-predators-dry-valley-lakes-antarctica00878nas a2200277 4500008004100000245006500041210006400106260001200170300001200182490000700194653002300201100002400224700001700248700002400265700002000289700002100309700002100330700002400351700002400375700002400399700002100423700002000444700002400464700002300488856008900511 1999 eng d00aPhysical controls on the Taylor Valley Ecosystem, Antarctica0 aPhysical controls on the Taylor Valley Ecosystem Antarctica c12/1999 a961-9720 v4910aWater availability1 aFountain, Andrew, G1 aLyons, Berry1 aBurkins, Melody, B.1 aDana, Gayle, L.1 aDoran, Peter, T.1 aLewis, Karen, J.1 aMcKnight, Diane, M.1 aMoorhead, Daryl, L.1 aParsons, Andrew, N.1 aPriscu, John, C.1 aWall, Diana, H.1 aWharton, Robert, A.1 aVirginia, Ross, A. uhttps://mcm.lternet.edu/content/physical-controls-taylor-valley-ecosystem-antarctica00492nas a2200121 4500008004100000245007500041210006900116260003800185490001000223100001800233700001700251856010200268 1998 eng d00aChemical Weathering in Taylor Valley, Antarctica: Quantity and Quality0 aChemical Weathering in Taylor Valley Antarctica Quantity and Qua bUniversity of Alabama, Tuscaloosa0 vPh.D.1 aNezat, C., A.1 aLyons, Berry uhttps://mcm.lternet.edu/content/chemical-weathering-taylor-valley-antarctica-quantity-and-quality00568nas a2200145 4500008004100000245008700041210006900128300001200197490000700209100002400216700002200240700002800262700002100290856011100311 1998 eng d00aCyanobacterial communities associated with mineral particles in antarctic lake ice0 aCyanobacterial communities associated with mineral particles in  a224-2250 v311 aGordon, Douglas, A.1 aLanoil, Brian, D.1 aGiovannoni, Stephen, J.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/cyanobacterial-communities-associated-mineral-particles-antarctic-lake-ice00540nas a2200133 4500008004100000245009300041210006900134300001200203490000700215100002100222700002400243700002000267856011900287 1998 eng d00aEnergy balance studies of Canada Glacier, Taylor Valley, McMurdo Dry Valleys, Antarctica0 aEnergy balance studies of Canada Glacier Taylor Valley McMurdo D a603-6090 v271 aLewis, Karen, J.1 aFountain, Andrew, G1 aDana, Gayle, L. uhttps://mcm.lternet.edu/content/energy-balance-studies-canada-glacier-taylor-valley-mcmurdo-dry-valleys-antarctica00605nas a2200169 4500008004100000245008000041210006900121300001200190490000700202100002100209700002000230700001900250700002200269700002100291700001700312856010600329 1998 eng d00aEvidence of deep circulation in two perennially ice-covered Antarctic lakes0 aEvidence of deep circulation in two perennially icecovered Antar a625-6350 v431 aTyler, Scott, W.1 aCook, Peter, G.1 aButt, Anya, Z.1 aThomas, James, M.1 aDoran, Peter, T.1 aLyons, Berry uhttps://mcm.lternet.edu/content/evidence-deep-circulation-two-perennially-ice-covered-antarctic-lakes00747nas a2200205 4500008004100000245009700041210006900138300001000207490000700217100001700224700002400241700001900265700002300284700002000307700002300327700002400350700002400374700002100398856012200419 1998 eng d00aGeochemical Linkages Among Glaciers, Streams, and Lakes Within the Taylor Valley, Antarctica0 aGeochemical Linkages Among Glaciers Streams and Lakes Within the a77-920 v721 aLyons, Berry1 aWelch, Kathleen, A.1 aNeumann, Klaus1 aToxey, Jeffrey, K.1 aMcArthur, Robyn1 aWilliams, Changela1 aMcKnight, Diane, M.1 aMoorhead, Daryl, L.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/geochemical-linkages-among-glaciers-streams-and-lakes-within-taylor-valley-antarctica00571nas a2200157 4500008004100000245007600041210006900117300001000186490000700196100002400203700002000227700002100247700002200268700002400290856009900314 1998 eng d00aGlaciers of the McMurdo Dry Valleys, Southern Victoria Land, Antarctica0 aGlaciers of the McMurdo Dry Valleys Southern Victoria Land Antar a65-750 v721 aFountain, Andrew, G1 aDana, Gayle, L.1 aLewis, Karen, J.1 aVaughn, Bruce, H.1 aMcKnight, Diane, M. uhttps://mcm.lternet.edu/content/glaciers-mcmurdo-dry-valleys-southern-victoria-land-antarctica00570nas a2200133 4500008004100000245012200041210006900163300001200232490000700244100001900251700001700270700002200287856012700309 1998 eng d00aInorganic carbon-isotope distribution and budget in the Lake Hoare and Lake Fryxell basins, Taylor Valley, Antarctica0 aInorganic carbonisotope distribution and budget in the Lake Hoar a685-6900 v271 aNeumann, Klaus1 aLyons, Berry1 aMarais, D.J., Des uhttps://mcm.lternet.edu/content/inorganic-carbon-isotope-distribution-and-budget-lake-hoare-and-lake-fryxell-basins-taylor00612nas a2200157 4500008004100000245009600041210006900137300001200206490000700218100001700225700002100242700002400263700002400287700002200311856012100333 1998 eng d00aA late holocene dessication of Lake Hoare and Lake Fryxell, McMurdo Dry Valleys, Antarctica0 alate holocene dessication of Lake Hoare and Lake Fryxell McMurdo a247-2560 v101 aLyons, Berry1 aTyler, Scott, W.1 aWharton, Robert, A.1 aMcKnight, Diane, M.1 aVaughn, Bruce, H. uhttps://mcm.lternet.edu/content/late-holocene-dessication-lake-hoare-and-lake-fryxell-mcmurdo-dry-valleys-antarctica00509nas a2200145 4500008004100000245006800041210006400109300000800173490000700181100001700188700002400205700002100229700001900250856009400269 1998 eng d00aMcMurdo Dry Valleys LTER: Density-driven mixing in Lake Hoare?0 aMcMurdo Dry Valleys LTER Densitydriven mixing in Lake Hoare a2050 v311 aLyons, Berry1 aWelch, Kathleen, A.1 aTyler, Scott, W.1 aSharma, Pankaj uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-lter-density-driven-mixing-lake-hoare00554nas a2200133 4500008004100000245010100041210006900142300001200211490000700223100002400230700002100254700002000275856012500295 1998 eng d00aMcMurdo Dry Valleys LTER: Spatial variation of glacier mass balance in Taylor Valley, Antarctica0 aMcMurdo Dry Valleys LTER Spatial variation of glacier mass balan a194-1950 v311 aFountain, Andrew, G1 aLewis, Karen, J.1 aDana, Gayle, L. uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-lter-spatial-variation-glacier-mass-balance-taylor-valley-antarctica00552nas a2200133 4500008004100000245010300041210006900144300001200213490000700225100002100232700002400253700001900277856012200296 1998 eng d00aMcMurdo Dry Valleys LTER: The role of terminus cliff melt in streamflow, Taylor Valley, Antarctica0 aMcMurdo Dry Valleys LTER The role of terminus cliff melt in stre a189-1900 v311 aLewis, Karen, J.1 aFountain, Andrew, G1 aLangevin, Paul uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-lter-role-terminus-cliff-melt-streamflow-taylor-valley-antarctica00762nas a2200241 4500008004100000245007100041210006900112260001200181300001400193490000800207653001100215100002100226700002700247700002200274700002800296700002000324700002700344700002100371700002400392700002200416700002400438856005800462 1998 eng d00aPerennial Antarctic Lake Ice: An Oasis for Life in a Polar Desert0 aPerennial Antarctic Lake Ice An Oasis for Life in a Polar Desert c06/1998 a2095-20980 v28010aBiggie1 aPriscu, John, C.1 aFritsen, Christian, H.1 aAdams, Edward, E.1 aGiovannoni, Stephen, J.1 aPaerl, Hans, W.1 aMcKay, Christopher, P.1 aDoran, Peter, T.1 aGordon, Douglas, A.1 aLanoil, Brian, D.1 aPinckney, James, L. uhttp://www.sciencemag.org/content/280/5372/2095.short00548nas a2200121 4500008004100000245012600041210006900167300001200236490000700248100002500255700002100280856012500301 1998 eng d00aPigment Analysis of the Distribution, Succession, and Fate of Phytoplankton in the McMurdo Dry Valley Lakes of Antarctica0 aPigment Analysis of the Distribution Succession and Fate of Phyt a229-2390 v721 aLizotte, Michael, P.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/pigment-analysis-distribution-succession-and-fate-phytoplankton-mcmurdo-dry-valley-lakes00556nas a2200133 4500008004100000245010200041210006900143300001200212490000700224100002000231700002000251700002800271856012300299 1998 eng d00aProtozooplankton and Microzooplankton Ecology in Lakes of the Dry Valleys, Southern Victoria Land0 aProtozooplankton and Microzooplankton Ecology in Lakes of the Dr a255-2670 v721 aJames, Mark, R.1 aHall, Julie, A.1 aLaybourn-Parry, Johanna uhttps://mcm.lternet.edu/content/protozooplankton-and-microzooplankton-ecology-lakes-dry-valleys-southern-victoria-land00560nas a2200133 4500008004100000245010400041210006900145300001200214490000700226100002100233700002400254700002000278856012800298 1998 eng d00aSurface energy balance and meltwater production for a Dry Valley glacier, Taylor Valley, Antarctica0 aSurface energy balance and meltwater production for a Dry Valley a603-6090 v271 aLewis, Karen, J.1 aFountain, Andrew, G1 aDana, Gayle, L. uhttps://mcm.lternet.edu/content/surface-energy-balance-and-meltwater-production-dry-valley-glacier-taylor-valley-antarctica00564nas a2200157 4500008004100000245007000041210006900111300001200180490000700192100002500199700001600224700002200240700002700262700002100289856009600310 1998 eng d00aTransparency of Antarctic ice-covered lakes to solar UV radiation0 aTransparency of Antarctic icecovered lakes to solar UV radiation a618-6240 v431 aVincent, Warwick, F.1 aRae, Rowena1 aLaurion, Isabelle1 aHoward-Williams, Clive1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/transparency-antarctic-ice-covered-lakes-solar-uv-radiation00597nas a2200169 4500008004100000245007200041210006700113260002900180300001200209100001700221700002400238700001700262700001700279700002700296700001500323856008900338 1997 eng d00aThe abundance of planktonic virus-like particles in Antarctic lakes0 aabundance of planktonic viruslike particles in Antarctic lakes aRotterdambBalkema Press a241-2501 aKepner, R.L.1 aWharton, Robert, A.1 aGalchenko, V1 aLyons, Berry1 aHoward-Williams, Clive1 aHawes, Ian uhttps://mcm.lternet.edu/content/abundance-planktonic-virus-particles-antarctic-lakes00661nas a2200169 4500008004100000245009900041210006900140260002900209300001200238100002400250700001700274700002400291700001700315700002700332700001500359856011700374 1997 eng d00aCarbon dynamics of aquatic microbial mats in the Antarctic dry valleys: A modelling synthesis0 aCarbon dynamics of aquatic microbial mats in the Antarctic dry v bBalkema Press, Rotterdam a181-1961 aMoorhead, Daryl, L.1 aDavis, Shane1 aWharton, Robert, A.1 aLyons, Berry1 aHoward-Williams, Clive1 aHawes, Ian uhttps://mcm.lternet.edu/content/carbon-dynamics-aquatic-microbial-mats-antarctic-dry-valleys-modelling-synthesis00811nas a2200217 4500008004100000245012400041210006900165260002900234300001200263100001700275700002400292700001800316700001400334700002300348700001900371700002400390700001700414700002700431700001500458856012000473 1997 eng d00aChemical weathering rates and reactions in the Lake Fryxell Basin, Taylor Valley : Comparison to temperate river basins0 aChemical weathering rates and reactions in the Lake Fryxell Basi bBalkema Press, Rotterdam a147-1541 aLyons, Berry1 aWelch, Kathleen, A.1 aNezat, C., A.1 aCrick, K.1 aToxey, Jeffrey, K.1 aMastrine, J.A.1 aMcKnight, Diane, M.1 aLyons, Berry1 aHoward-Williams, Clive1 aHawes, Ian uhttps://mcm.lternet.edu/content/chemical-weathering-rates-and-reactions-lake-fryxell-basin-taylor-valley-comparison00670nas a2200181 4500008004100000245009200041210006900133260002900202300001200231100001700243700002200260700002300282700002100305700001700326700002700343700001500370856010300385 1997 eng d00aClimate history of the McMurdo Dry Valleys since the last glacial maximum: A synthesis0 aClimate history of the McMurdo Dry Valleys since the last glacia bBalkema Press, Rotterdam a155-1621 aLyons, Berry1 aBartek, Louis, R.1 aMayewski, Paul, A.1 aDoran, Peter, T.1 aLyons, Berry1 aHoward-Williams, Clive1 aHawes, Ian uhttps://mcm.lternet.edu/content/climate-history-mcmurdo-dry-valleys-last-glacial-maximum-synthesis00602nas a2200145 4500008004100000245009900041210006900140260003900209300001200248100001400260700001900274700001700293700002400310856012200334 1997 eng d00aDetermination of rare earth elements in Antarctic lakes and streams of varying ionic strengths0 aDetermination of rare earth elements in Antarctic lakes and stre aLondonbRoyal Society of Chemistry a253-2621 aGraham, E1 aRamsey, L., A.1 aLyons, Berry1 aWelch, Kathleen, A. uhttps://mcm.lternet.edu/content/determination-rare-earth-elements-antarctic-lakes-and-streams-varying-ionic-strengths00369nas a2200121 4500008004100000245004000041210004000081300001400121490000700135100001700142700002400159856006400183 1997 eng d00aLithium in waters of a polar desert0 aLithium in waters of a polar desert a4309-43190 v611 aLyons, Berry1 aWelch, Kathleen, A. uhttps://mcm.lternet.edu/content/lithium-waters-polar-desert00462nas a2200145 4500008004100000245004200041210003800083260002900121300001200150100002800162700001700190700002700207700001500234856006700249 1997 eng d00aThe microbial loop in Antarctic lakes0 amicrobial loop in Antarctic lakes aRotterdambBalkema Press a231-2401 aLaybourn-Parry, Johanna1 aLyons, Berry1 aHoward-Williams, Clive1 aHawes, Ian uhttps://mcm.lternet.edu/content/microbial-loop-antarctic-lakes00675nas a2200169 4500008004100000245011500041210006900156300001000225490000700235100002800242700002000270700002400290700002100314700002500335700001900360856012600379 1997 eng d00aThe microbial plankton of Lake Fryxell, southern Victoria Land, Antarctica during the summers of 1992 and 19940 amicrobial plankton of Lake Fryxell southern Victoria Land Antarc a54-610 v171 aLaybourn-Parry, Johanna1 aJames, Mark, R.1 aMcKnight, Diane, M.1 aPriscu, John, C.1 aSpaulding, Sarah, A.1 aShiel, Russell uhttps://mcm.lternet.edu/content/microbial-plankton-lake-fryxell-southern-victoria-land-antarctica-during-summers-1992-and00806nas a2200253 4500008004100000245008400041210006900125260001200194300001000206490000600216100001900222700001800241700002400259700001800283700001400301700001600315700001700331700001400348700001800362700002400380700001600404700002300420856010900443 1997 eng d00aOpen-top Designs for Manipulating Field Temperature in High-Latitude Ecosystems0 aOpentop Designs for Manipulating Field Temperature in HighLatitu c12/1997 a20-320 v31 aMarion, G., M.1 aHenry, G.H.R.1 aFreckman, Diana, W.1 aJohnstone, J.1 aJones, G.1 aJones, M.H.1 aLevesque, E.1 aMolau, U.1 aMØLGAARD, P.1 aParsons, Andrew, N.1 aSvoboda, J.1 aVirginia, Ross, A. uhttps://mcm.lternet.edu/content/open-top-designs-manipulating-field-temperature-high-latitude-ecosystems00672nas a2200181 4500008004100000245008800041210006900129260002900198300001200227100002700239700001500266700002400281700002000305700001700325700002700342700001500369856010600384 1997 eng d00aSources and sinks of nutrients in a polar desert stream, the Onyx River, Antarctica0 aSources and sinks of nutrients in a polar desert stream the Onyx aRotterdambBalkema Press a155-1701 aHoward-Williams, Clive1 aHawes, Ian1 aSchwarz, Anne-Maree1 aHall, Julie, A.1 aLyons, Berry1 aHoward-Williams, Clive1 aHawes, Ian uhttps://mcm.lternet.edu/content/sources-and-sinks-nutrients-polar-desert-stream-onyx-river-antarctica00795nas a2200193 4500008004100000245015600041210006900197260002900266300001200295100002000307700002000327700002400347700001900371700002500390700001700415700002700432700001500459856012700474 1997 eng d00aSpecies composition and primary production of algal communities in Dry Valley streams in Antarctica: Examination of the functional role of biodiversity0 aSpecies composition and primary production of algal communities  bBalkema Press, Rotterdam a171-1791 aNiyogi, Dev, K.1 aTate, Cathy, M.1 aMcKnight, Diane, M.1 aDuff, John, H.1 aAlger, Alexander, S.1 aLyons, Berry1 aHoward-Williams, Clive1 aHawes, Ian uhttps://mcm.lternet.edu/content/species-composition-and-primary-production-algal-communities-dry-valley-streams-antarctica00641nas a2200169 4500008004100000245010500041210006900146300001200215490000800227100002400235700001700259700001400276700001900290700002200309700001700331856012300348 1996 eng d00aDetermination of major element chemistry in terrestrial waters from Antarctica by ion chromatography0 aDetermination of major element chemistry in terrestrial waters f a257-2630 v7391 aWelch, Kathleen, A.1 aLyons, Berry1 aGraham, E1 aNeumann, Klaus1 aThomas, James, M.1 aMikesell, D. uhttps://mcm.lternet.edu/content/determination-major-element-chemistry-terrestrial-waters-antarctica-ion-chromatography00603nas a2200133 4500008004100000245015200041210006900193300001200262490000700274100002500281700002200306700002100328856012000349 1996 eng d00aPhytoplankton Dynamics in the Stratified Water Column of Lake Bonney, Antarctica. I. Biomass and Productivity During the Winter-Spring Transition0 aPhytoplankton Dynamics in the Stratified Water Column of Lake Bo a155-1620 v161 aLizotte, Michael, P.1 aSharp, Thomas, R.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/phytoplankton-dynamics-stratified-water-column-lake-bonney-antarctica-i-biomass-and00546nas a2200121 4500008004100000245010400041210006900145260002700214490000900241100002100250700002400271856012900295 1996 eng d00aSurface energy balance and meltwater production for a dry valley glacier, Taylor Valley, Antarctica0 aSurface energy balance and meltwater production for a dry valley bUniversity of Colorado0 vM.S.1 aLewis, Karen, J.1 aFountain, Andrew, G uhttps://mcm.lternet.edu/content/surface-energy-balance-and-meltwater-production-dry-valley-glacier-taylor-valley-antarctic-000483nas a2200121 4500008004100000245008600041210006900127300001200196490000700208100002400215700001700239856010500256 1995 eng d00aMcMurdo LTER: Comparative limnology of the Taylor Valley lakes: The major solutes0 aMcMurdo LTER Comparative limnology of the Taylor Valley lakes Th a292-2930 v301 aWelch, Kathleen, A.1 aLyons, Berry uhttps://mcm.lternet.edu/content/mcmurdo-lter-comparative-limnology-taylor-valley-lakes-major-solutes00544nas a2200145 4500008004100000245008200041210006900123300001200192490000700204100002100211700002000232700002100252700002400273856010100297 1995 eng d00aMcMurdo LTER: The surface-energy balance of the Canada Glacier, Taylor Valley0 aMcMurdo LTER The surfaceenergy balance of the Canada Glacier Tay a280-2820 v301 aLewis, Karen, J.1 aDana, Gayle, L.1 aTyler, Scott, W.1 aFountain, Andrew, G uhttps://mcm.lternet.edu/content/mcmurdo-lter-surface-energy-balance-canada-glacier-taylor-valley00688nas a2200181 4500008004100000245010100041210006900142300001200211490000700223100002400230700001700254700002100271700002000292700002400312700002200336700002400358856012400382 1994 eng d00aMcMurdo LTER: Inorganic geochemical studies with special reference to calcium carbonate dynamics0 aMcMurdo LTER Inorganic geochemical studies with special referenc a237-2390 v291 aWelch, Kathleen, A.1 aLyons, Berry1 aPriscu, John, C.1 aEdwards, R., L.1 aMcKnight, Diane, M.1 aHouse, Harold, R.1 aWharton, Robert, A. uhttps://mcm.lternet.edu/content/mcmurdo-lter-inorganic-geochemical-studies-special-reference-calcium-carbonate-dynamics00545nas a2200121 4500008004100000245011800041210006900159300001400228490000700242100002500249700002100274856012800295 1994 eng d00aNatural Fluorescence and Quantum Yields in Vertically Stationary Phytoplankton from Perennially Ice-Covered Lakes0 aNatural Fluorescence and Quantum Yields in Vertically Stationary a1399-14100 v391 aLizotte, Michael, P.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/natural-fluorescence-and-quantum-yields-vertically-stationary-phytoplankton-perennially-ice00452nas a2200133 4500008004100000245005800041210005700099300001100156490000700167100002100174700002400195700001700219856008200236 1994 eng d00aPaleolimnology of the McMurdo Dry Valleys, Antarctica0 aPaleolimnology of the McMurdo Dry Valleys Antarctica a85-1140 v101 aDoran, Peter, T.1 aWharton, Robert, A.1 aLyons, Berry uhttps://mcm.lternet.edu/content/paleolimnology-mcmurdo-dry-valleys-antarctica00588nas a2200121 4500008004100000245016800041210006900209300001200278490000700290100001700297700002300314856012900337 1993 eng d00aThe geochemical evolution of terrestrial waters in the antarctic: the role of rock-water interactions, in Physical and Biogeochemical Processes in Antarctic Lakes0 ageochemical evolution of terrestrial waters in the antarctic the a135-1430 v591 aLyons, Berry1 aMayewski, Paul, A. uhttps://mcm.lternet.edu/content/geochemical-evolution-terrestrial-waters-antarctic-role-rock-water-interactions-physical-and00557nas a2200133 4500008004100000245010300041210006900144300001200213490000800225100002400233700001700257700002200274856012700296 1993 eng d00aStable isotopic biogeochemistry of carbon and nitrogen in a perennially ice-covered Antarctic lake0 aStable isotopic biogeochemistry of carbon and nitrogen in a pere a159-1720 v1071 aWharton, Robert, A.1 aLyons, Berry1 aMarais, D.J., Des uhttps://mcm.lternet.edu/content/stable-isotopic-biogeochemistry-carbon-and-nitrogen-perennially-ice-covered-antarctic-lake00579nas a2200121 4500008004100000245016100041210006900202300001200271490000700283100002500290700002100315856012100336 1992 eng d00aPhotosynthesis-Irradiance Relationships in Phytoplankton From the Physically Stable Water Column of a Perennially Ice-Covered Lake (Lake Bonney, Antarctica)0 aPhotosynthesisIrradiance Relationships in Phytoplankton From the a179-1850 v281 aLizotte, Michael, P.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/photosynthesis-irradiance-relationships-phytoplankton-physically-stable-water-column00550nas a2200121 4500008004100000245013100041210006900172300000900241490000700250100002500257700002100282856012500303 1992 eng d00aSpectral Irradiance and Bio-Optical Properties in Perennially Ice-Covered Lakes of the Dry Valleys (McMurdo Sound, Antarctica)0 aSpectral Irradiance and BioOptical Properties in Perennially Ice a1-140 v571 aLizotte, Michael, P.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/spectral-irradiance-and-bio-optical-properties-perennially-ice-covered-lakes-dry-valleys