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/s40168-023-01719-302587nas a2200313 4500008004100000022001400041245012700055210006900182260001200251300001100263520145800274653001701732653001401749653000801763653001901771653001501790100002301805700001801828700001501846700002401861700002501885700003301910700002901943700001701972700002201989700002102011700002102032856022002053 2024 eng d a0954-102000aMcMurdo Dry Valley lake edge ‘moats’: The ecological intersection between terrestrial and aquatic polar desert habitat0 aMcMurdo Dry Valley lake edge moats The ecological intersection b c04/2024 a1 - 173 a

Aquatic ecosystems - lakes, ponds and streams - are hotspots of biodiversity in the cold and arid environment of Continental Antarctica. Environmental change is expected to increasingly alter Antarctic aquatic ecosystems and modify the physical characteristics and interactions within the habitats that they support. Here, we describe physical and biological features of the peripheral ‘moat’ of a closed-basin Antarctic lake. These moats mediate connectivity amongst streams, lake and soils. We highlight the cyclical moat transition from a frozen winter state to an active open-water summer system, through refreeze as winter returns. Summer melting begins at the lakebed, initially creating an ice-constrained lens of liquid water in November, which swiftly progresses upwards, creating open water in December. Conversely, freezing progresses slowly from the water surface downwards, with water at 1 m bottom depth remaining liquid until May. Moats support productive, diverse benthic communities that are taxonomically distinct from those under the adjacent permanent lake ice. We show how ion ratios suggest that summer exchange occurs amongst moats, streams, soils and sub-ice lake water, perhaps facilitated by within-moat density-driven convection. Moats occupy a small but dynamic area of lake habitat, are disproportionately affected by recent lake-level rises and may thus be particularly vulnerable to hydrological change.

10aconnectivity10aecosystem10aice10amicrobial mats10atransition1 aStone, Michael, S.1 aDevlin, Shawn1 aHawes, Ian1 aWelch, Kathleen, A.1 aGooseff, Michael, N.1 aTakacs-Vesbach, Cristina, D.1 aMorgan-Kiss, Rachael, M.1 aAdams, Byron1 aBarrett, John, E.1 aPriscu, John, C.1 aDoran, Peter, T. uhttps://www.cambridge.org/core/journals/antarctic-science/article/mcmurdo-dry-valley-lake-edge-moats-the-ecological-intersection-between-terrestrial-and-aquatic-polar-desert-habitats/31D94DD51E651603482A3AE6E8A52A5701497nas a2200169 4500008004100000022001400041245012500055210006900180260001200249300001400261490000700275520092800282100001901210700001601229700002001245856006201265 2023 eng d a1084-545300aBetter together? The values, obstacles, opportunities, and prospects for collaborative research in environmental history0 aBetter together The values obstacles opportunities and prospects c04/2023 a269 - 2990 v283 a

Environmental historians have long argued for the value of collaborative research, many have called for more of it, and some have experimented with new forms of teamwork. Yet data gathered from three prominent journals—Environmental History, Environment and History, and the Journal of Historical Geography—show that, over the fifteen-year period from 2006 through 2020, coauthorship on published research remained remarkably rare, with no discernible trend over time. Why do environmental historians still collaborate so infrequently on published research? What are the causes and consequences of this failure to work together? And how can we help better fulfill long-standing calls in our field for a more collaborative research culture? This essay answers these questions, and it offers practical remedies for fostering a culture of greater collaboration in environmental history.

1 aAlagona, Peter1 aCarey, Mark1 aHowkins, Adrian uhttps://www.journals.uchicago.edu/doi/full/10.1086/72378402499nas a2200277 4500008004100000245009500041210006900136260001200205300000800217490000700225520169100232653001001923653002701933653001801960653002501978653001502003100002302018700002202041700001802063700002202081700001902103700001702122700002002139700001802159856004402177 2023 eng d00aBiogeography and genetic diversity of terrestrial mites in the Ross Sea region, Antarctica0 aBiogeography and genetic diversity of terrestrial mites in the R c03/2023 a6060 v143 a

Free-living terrestrial mites (Acari) have persisted through numerous glacial cycles in Antarctica. Very little is known, however, of their genetic diversity and distribution, particularly within the Ross Sea region. To redress this gap, we sampled mites throughout the Ross Sea region, East Antarctica, including Victoria Land and the Queen Maud Mountains (QMM), covering a latitudinal range of 72–85 °S, as well as Lauft Island near Mt. Siple (73 °S) in West Antarctica and Macquarie Island (54 °S) in the sub-Antarctic. We assessed genetic diversity using mitochondrial cytochrome c oxidase subunit I gene sequences (COI-5P DNA barcode region), and also morphologically identified voucher specimens. We obtained 130 sequences representing four genera: Nanorchestes (n = 30 sequences), Stereotydeus (n = 46), Coccorhagidia (n = 18) and Eupodes (n = 36). Tree-based analyses (maximum likelihood) revealed 13 genetic clusters, representing as many as 23 putative species indicated by barcode index numbers (BINs) from the Barcode of Life Datasystems (BOLD) database. We found evidence for geographically-isolated cryptic species, e.g., within Stereotydeus belli and S. punctatus, as well as unique genetic groups occurring in sympatry (e.g., Nanorchestes spp. in QMM). Collectively, these data confirm high genetic divergence as a consequence of geographic isolation over evolutionary timescales. From a conservation perspective, additional targeted sampling of understudied areas in the Ross Sea region should be prioritised, as further diversity is likely to be found in these short-range endemic mites.

10aAcari10aAntarctic conservation10aDNA barcoding10ageographic isolation10aspeciation1 aCollins, Gemma, E.1 aYoung, Monica, R.1 aConvey, Peter1 aChown, Steven, L.1 aCary, Craig, S1 aAdams, Byron1 aWall, Diana, H.1 aHogg, Ian, D. uhttps://www.mdpi.com/2073-4425/14/3/60603072nas a2200253 4500008004100000022001400041245011200055210006900167260001200236490000700248520227400255653001902529653001702548653002102565653002002586653001902606653001502625100002202640700002402662700002502686700002402711700002602735856005702761 2023 eng d a2161-954900aDifferentiating physical and biological storage of nitrogen along an intermittent Antarctic stream corridor0 aDifferentiating physical and biological storage of nitrogen alon c09/20230 v423 a

In many temperate streams, biological uptake of N acts to attenuate the transport of excess N from allochthonous anthropogenic imports. Relatively few studies have determined how this N uptake relates to the magnitude of physical vs. biological N storage in the stream corridor, especially for intermittent systems where allochthonous N imports are often low and N transport may only occur during brief periods of streamflow. Glacial meltwater streams in the McMurdo Dry Valleys of Antarctica provide an excellent setting to quantify autochthonous N cycling and storage processes supported by abundant algal mats and well-connected hyporheic zones. We combined historic point-scale sediment and periphyton sample datasets with remote sensing-based modeling of periphyton coverage to estimate how much N was stored in periphyton biomass and the hyporheic zone of a 5-km long McMurdo Dry Valley stream corridor (>100,000 m2). We contextualized these N storage calculations by estimating the magnitude of annual N imports to and exports from the stream corridor based on >2 decades of streamflow and surface water data, source glacier ice cores and meltwater data, and past studies of local aeolian deposition and biological N fixation rates. We found that in this highly oligotrophic system, stream corridor-scale N storage was ~1000x that of total annual N import or export fluxes. More than 90% of this temporarily stored N was autochthonous organic matter in the shallow (<10 cm) hyporheic zone, which acts as a reservoir that sustains N availability in the water column. Despite its location in a polar desert devoid of higher-order vegetation, area-normalized N storage (~40 g N/m2) was greater than that reported for streams at lower latitudes (~1–22 g N/m2). We also demonstrated that NH4+ sorption to stream sediment may be an important physicochemical N storage mechanism that responds to short-term fluctuations in streamflow and governs the mobility of inorganic N. Altogether, this research illustrates the importance of quantifying N storage within stream corridors when evaluating the significance of internal cycling and physical retention processes that modulate N availability.

10ahyporheic zone10aMcMurdo LTER10anitrogen cycling10anutrient budget10aorganic matter10aperiphyton1 aSingley, Joel, G.1 aSalvatore, Mark, R.1 aGooseff, Michael, N.1 aMcKnight, Diane, M.1 aHinckley, Eve-Lyn, S. uhttps://www.journals.uchicago.edu/doi/10.1086/72567602814nas a2200373 4500008004100000022001400041245010900055210006900164260001200233520170200245653002001947653001001967653001101977653001201988653001102000653001102011100002502022700001902047700001902066700001702085700002102102700002302123700002402146700002502170700002402195700002602219700002102245700002202266700002202288700002102310700001802331700002202349856006902371 2023 eng d a0886-623600aLong-term changes in concentration and yield of riverine dissolved silicon from the poles to the tropics0 aLongterm changes in concentration and yield of riverine dissolve c08/20233 a

Riverine exports of silicon (Si) influence global carbon cycling through the growth of marine diatoms, which account for ∼25% of global primary production. Climate change will likely alter river Si exports in biome-specific ways due to interacting shifts in chemical weathering rates, hydrologic connectivity, and metabolic processes in aquatic and terrestrial systems. Nonetheless, factors driving long-term changes in Si exports remain unexplored at local, regional, and global scales. We evaluated how concentrations and yields of dissolved Si (DSi) changed over the last several decades of rapid climate warming using long-term datasets from 60 rivers and streams spanning the globe (e.g., Antarctic, tropical, temperate, boreal, alpine, Arctic systems). We show that widespread changes in river DSi concentration and yield have occurred, with the most substantial shifts occurring in alpine and polar regions. The magnitude and direction of trends varied within and among biomes, were most strongly associated with differences in land cover, and were often independent of changes in river discharge. These findings indicate that there are likely diverse mechanisms driving change in river Si biogeochemistry that span the land-water interface, which may include glacial melt, changes in terrestrial vegetation, and river productivity. Finally, trends were often stronger in months outside of the growing season, particularly in temperate and boreal systems, demonstrating a potentially important role of shifting seasonality for the flux of Si from rivers. Our results have implications for the timing and magnitude of silica processing in rivers and its delivery to global oceans.

10abiogeochemistry10ariver10asilica10asilicon10astream10atrends1 aJankowski, Kathi, Jo1 aJohnson, Keira1 aSethna, Lienne1 aJulian, Paul1 aWymore, Adam, S.1 aShogren, Arial, J.1 aThomas, Patrick, K.1 aSullivan, Pamela, L.1 aMcKnight, Diane, M.1 aMcDowell, William, H.1 aHeindel, Ruth, C1 aJones, Jeremy, B.1 aWollheim, Wilfred1 aAbbott, Benjamin1 aDeegan, Linda1 aCarey, Joanna, C. uhttps://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GB00767802348nas a2200253 4500008004100000022001400041245009900055210006900154260001200223300001100235520137700246653002501623653001901648653002401667653003201691653001701723100002601740700002401766700002501790700002501815700003201840700002001872856020201892 2023 eng d a0022-143000aMeteorological drivers of melt at two nearby glaciers in the McMurdo Dry Valleys of Antarctica0 aMeteorological drivers of melt at two nearby glaciers in the McM c12/2023 a1 - 133 a

We study the meteorological drivers of melt at two glaciers in Taylor Valley, Antarctica, using 22 years of weather station observations and surface energy fluxes. The glaciers are located only 30 km apart, but have different local climates; Taylor Glacier is generally drier and windier than Commonwealth Glacier, which receives more snowfall due to its proximity to the coast. Commonwealth Glacier shows more inter-annual melt variability, explained by variable albedo due to summer snowfall events. A significant increase in surface melt at Commonwealth Glacier is associated with a decrease in summer minimum albedo. Inter-annual variability in melt at both glaciers is linked to degree-days above freezing during föhn events, occurring more frequently at Taylor Glacier. At Taylor Glacier melt occurs most often with positive air temperatures, but föhn conditions also favour sublimation, which cools the surface and prevents melt for the majority of the positive air temperatures. At Commonwealth Glacier, most of the melt instead occurs with sub-zero air temperatures, driven by strong solar radiative heating. Future melt at Taylor Glacier will likely be more sensitive to changes in föhn events, while Commonwealth Glacier will be impacted more by changes in near coastal weather, where moisture inputs can drive cloud cover, snowfall and change albedo.

10aAntarctic glaciology10aenergy balance10aglacier meteorology10aice/atmosphere interactions10amelt-surface1 aHofsteenge, Marte, G.1 aCullen, Nicolas, J.1 aConway, Jonathan, P.1 aReijmer, Carleen, H.1 avan den Broeke, Michiel, R.1 aKaturji, Marwan uhttps://www.cambridge.org/core/journals/journal-of-glaciology/article/meteorological-drivers-of-melt-at-two-nearby-glaciers-in-the-mcmurdo-dry-valleys-of-antarctica/2B8ED17DEC26AB5F0905BC4C7ACA02FA02259nas 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.01254-2202770nas a2200241 4500008004100000245007200041210006900113260001200182300000800194490000700202520208300209653001502292653001902307653001902326653001302345653002202358653002102380100002902401700002002430700001302450700002102463856004402484 2023 eng d00aTemperature response of metabolic activity of an Antarctic nematode0 aTemperature response of metabolic activity of an Antarctic nemat c01/2023 a1090 v123 a

Because of climate change, the McMurdo Dry Valleys of Antarctica (MCM) have experienced an increase in the frequency and magnitude of summer pulse warming and surface ice and snow melting events. In response to these environmental changes, some nematode species in the MCM have experienced steady population declines over the last three decades, but Plectus murrayi, a mesophilic nematode species, has responded with a steady increase in range and abundance. To determine how P. murrayi responds to increasing temperatures, we measured metabolic heat and CO2 production rates and calculated O2 consumption rates as a function of temperature at 5 °C intervals from 5 to 50 °C. Heat, CO2 production, and O2 consumption rates increase approximately exponentially up to 40 °C, a temperature never experienced in their polar habitat. Metabolic rates decline rapidly above 40 °C and are irreversibly lost at 50 °C due to thermal stress and mortality. Caenorhabditis elegans, a much more widespread nematode that is found in more temperate environments reaches peak metabolic heat rate at just 27 °C, above which it experiences high mortality due to thermal stress. At temperatures from 10 to 40 °C, P. murrayi produces about 6 times more CO2 than the O2 it consumes, a respiratory quotient indicative of either acetogenesis or de novo lipogenesis. No potential acetogenic microbes were identified in the P. murrayi microbiome, suggesting that P. murrayi is producing increased CO2 as a byproduct of de novo lipogenesis. This phenomenon, in conjunction with increased summer temperatures in their polar habitat, will likely lead to increased demand for carbon and subsequent increases in CO2 production, population abundance, and range expansion. If such changes are not concomitant with increased carbon inputs, we predict the MCM soil ecosystems will experience dramatic declines in functional and taxonomic diversity.

10aAntarctica10acarbon cycling10aclimate change10anematode10arespiration rates10asoil temperature1 aRobinson, Colin, Michael1 aHansen, Lee, D.1 aXue, Xia1 aAdams, Byron, J. uhttps://www.mdpi.com/2079-7737/12/1/10901137nas 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.2022.74083802206nas a2200229 4500008004100000022001400041245015000055210006900205260001200274300001400286490000700300520141400307653001801721653001501739653001801754100002101772700001601793700001901809700002901828700002601857856009301883 2022 eng d a0954-102000aAntibiotic resistance genes and taxa analysis from mat and planktonic microbiomes of Antarctic perennial ice-covered Lake Fryxell and Lake Bonney0 aAntibiotic resistance genes and taxa analysis from mat and plank c12/2022 a408 - 4220 v343 a

The perennial ice-covered lakes of the Antarctic McMurdo Dry Valleys harbour oligotrophic microbial communities that are separated geographically from other aquatic systems. Their microbiomes include planktonic microbes as well as lift-off mat communities that emerge from the ice. We used the ShortBRED protein family profiler to quantify the antibiotic resistance genes (ARGs) from metagenomes of lift-off mats emerging from ice and from filtered water samples of Lake Fryxell and Lake Bonney. The overall proportion of ARG hits was similar to that found in temperate-zone rural ponds with moderate human inputs. Specific ARGs showed distinct distributions for the two lakes and for mat vs planktonic sources. Metagenomic taxa distributions showed that mat phototrophs consisted mainly of cyanobacteria or Betaproteobacteria, whereas the water column phototrophs were mainly protists. An enrichment culture of the Betaproteobacterium Rhodoferax antarcticus from a Lake Fryxell mat sample showed an unusual mat-forming phenotype not previously reported for this species. Its genome showed no ARGs associated with Betaproteobacteria but had ARGs consistent with a minor Pseudomonas component. The Antarctic lake mats and water showed specific ARGs distinctive to the mat and water sources, but overall ARG levels were similar to those of temperate water bodies with moderate human inputs.

10amicrobial mat10aRhodoferax10aTaylor Valley1 aTallada, Sheetal1 aHall, Grant1 aBarich, Daniel1 aMorgan-Kiss, Rachael, M.1 aSlonczewski, Joan, L. uhttps://www.cambridge.org/core/product/identifier/S0954102022000360/type/journal_article02219nas a2200349 4500008004100000022001400041245012300055210006900178260001200247520113200259653000901391653001901400653001601419653001201435653000901447653001301456100002001469700002501489700001601514700002501530700002101555700001701576700002501593700002501618700002101643700002501664700002601689700002201715700002301737700001801760856009101778 2022 eng d a0006-356800aCross-site comparisons of dryland ecosystem response to climate change in the US Long-Term Ecological Research Network0 aCrosssite comparisons of dryland ecosystem response to climate c c08/20223 a

Long-term observations and experiments in diverse drylands reveal how ecosystems and services are responding to climate change. To develop generalities about climate change impacts at dryland sites, we compared broadscale patterns in climate and synthesized primary production responses among the eight terrestrial, nonforested sites of the United States Long-Term Ecological Research (US LTER) Network located in temperate (Southwest and Midwest) and polar (Arctic and Antarctic) regions. All sites experienced warming in recent decades, whereas drought varied regionally with multidecadal phases. Multiple years of wet or dry conditions had larger effects than single years on primary production. Droughts, floods, and wildfires altered resource availability and restructured plant communities, with greater impacts on primary production than warming alone. During severe regional droughts, air pollution from wildfire and dust events peaked. Studies at US LTER drylands over more than 40 years demonstrate reciprocal links and feedbacks among dryland ecosystems, climate-driven disturbance events, and climate change.

10aANPP10aclimate change10aDisturbance10adrought10aLTER10awildfire1 aHudson, Amy, R.1 aPeters, Debra, P. C.1 aBlair, J.M.1 aChilders, Daniel, L.1 aDoran, Peter, T.1 aGeil, Kerrie1 aGooseff, Michael, N.1 aGross, Katherine, L.1 aHaddad, Nick, M.1 aPastore, Melissa, A.1 aRudgers, Jennifer, A.1 aSala, Osvaldo, E.1 aSeabloom, Eric, W.1 aShaver, Gaius uhttps://academic.oup.com/bioscience/advance-article/doi/10.1093/biosci/biab134/665484002454nas a2200277 4500008004100000245020000041210006900241260001200310300001400322490000800336520152000344653001501864653001401879653002501893653001801918653001701936653000801953100002401961700001601985700002102001700001902022700001802041700002302059700002902082856006502111 2022 eng d00aCyclic electron flow (CEF) and ascorbate pathway activity provide constitutive photoprotection for the photopsychrophile, Chlamydomonas sp. UWO 241 (renamed Chlamydomonas priscuii)0 aCyclic electron flow CEF and ascorbate pathway activity provide  c03/2022 a235 - 2500 v1513 a

Under environmental stress, plants and algae employ a variety of strategies to protect the photosynthetic apparatus and maintain photostasis. To date, most studies on stress acclimation have focused on model organisms which possess limited to no tolerance to stressful extremes. We studied the ability of the Antarctic alga Chlamydomonas sp. UWO 241 (UWO 241) to acclimate to low temperature, high salinity or high light. UWO 241 maintained robust growth and photosynthetic activity at levels of temperature (2 °C) and salinity (700 mM NaCl) which were nonpermissive for a mesophilic sister species, Chlamydomonas raudensis SAG 49.72 (SAG 49.72). Acclimation in the mesophile involved classic mechanisms, including downregulation of light harvesting and shifts in excitation energy between photosystem I and II. In contrast, UWO 241 exhibited high rates of PSI-driven cyclic electron flow (CEF) and a larger capacity for nonphotochemical quenching (NPQ). Furthermore, UWO 241 exhibited constitutively high activity of two key ascorbate cycle enzymes, ascorbate peroxidase and glutathione reductase and maintained a large ascorbate pool. These results matched the ability of the psychrophile to maintain low ROS under short-term photoinhibition conditions. We conclude that tight control over photostasis and ROS levels are essential for photosynthetic life to flourish in a native habitat of permanent photooxidative stress. We propose to rename this organism Chlamydomonas priscuii.

10aAntarctica10aascorbate10aCyclic electron flow10aPhotosystem I10aPsychrophile10aROS1 aStahl-Rommel, Sarah1 aKalra, Isha1 aD'Silva, Susanna1 aHahn, Mark, M.1 aPopson, Devon1 aCvetkovska, Marina1 aMorgan-Kiss, Rachael, M. uhttps://link.springer.com/article/10.1007/s11120-021-00877-502367nas 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.01330-2103274nas a2200313 4500008004100000245011700041210006900158260001200227300001100239490000700250520227300257653001502530653002502545653001802570653002702588653002802615653002302643653001902666100002202685700002802707700002302735700002302758700002502781700002202806700002202828700001502850700002302865856007202888 2022 eng d00aLipid biomarkers from microbial mats on the McMurdo Ice Shelf, Antarctica: Signatures for life in the cryosphere0 aLipid biomarkers from microbial mats on the McMurdo Ice Shelf An c06/2022 a9036210 v133 a

Persistent cold temperatures, a paucity of nutrients, freeze-thaw cycles, and the strongly seasonal light regime make Antarctica one of Earth’s least hospitable surface environments for complex life. Cyanobacteria, however, are well-adapted to such conditions and are often the dominant primary producers in Antarctic inland water environments. In particular, the network of meltwater ponds on the ‘dirty ice’ of the McMurdo Ice Shelf is an ecosystem with extensive cyanobacteria-dominated microbial mat accumulations. This study investigated intact polar lipids (IPLs), heterocyte glycolipids (HGs), and bacteriohopanepolyols (BHPs) in combination with 16S and 18S rRNA gene diversity in microbial mats of twelve ponds in this unique polar ecosystem. To constrain the effects of nutrient availability, temperature and freeze-thaw cycles on the lipid membrane composition, lipids were compared to stromatolite-forming cyanobacterial mats from ice-covered lakes in the McMurdo Dry Valleys as well as from (sub)tropical regions and hot springs. The 16S rRNA gene compositions of the McMurdo Ice Shelf mats confirm the dominance of Cyanobacteria and Proteobacteria while the 18S rRNA gene composition indicates the presence of Ochrophyta, Chlorophyta, Ciliophora, and other microfauna. IPL analyses revealed a predominantly bacterial community in the meltwater ponds, with archaeal lipids being barely detectable. IPLs are dominated by glycolipids and phospholipids, followed by aminolipids. The high abundance of sugar-bound lipids accords with a predominance of cyanobacterial primary producers. The phosphate-limited samples from the (sub)tropical, hot spring, and Lake Vanda sites revealed a higher abundance of aminolipids compared to those of the nitrogen-limited meltwater ponds, affirming the direct affects that N and P availability have on IPL compositions. The high abundance of polyunsaturated IPLs in the Antarctic microbial mats suggests that these lipids provide an important mechanism to maintain membrane fluidity in cold environments. High abundances of HG keto-ols and HG keto-diols, produced by heterocytous cyanobacteria, further support these findings and reveal a unique distribution compared to those from warmer climates.

10aAntarctica10abacteriohopanepolyol10acyanobacteria10aheterocyte glycolipids10ahomeoviscous adaptation10aintact polar lipid10amicrobial mats1 aEvans, Thomas, W.1 aKalambokidis, Maria, J.1 aJungblut, Anne, D.1 aMillar, Jasmin, L.1 aBauersachs, Thorsten1 aGrotheer, Hendrik1 aMackey, Tyler, J.1 aHawes, Ian1 aSummons, Roger, E. uhttps://www.frontiersin.org/articles/10.3389/fmicb.2022.903621/full02675nas a2200241 4500008004100000245018700041210006900228260001200297300000900309490000700318520179100325653003202116653002602148653002302174653003502197653001902232653002802251100002602279700002002305700002002325700002402345856006402369 2022 eng d00aPatterns of interdisciplinary collaboration resemble biogeochemical relationships in the McMurdo Dry Valleys, Antarctica: A historical social network analysis of science, 1907–20160 aPatterns of interdisciplinary collaboration resemble biogeochemi c04/2022 a80370 v413 a

Co-authorship networks can provide key insights into the production of scientific knowledge. This is particularly interesting in Antarctica, where most human activity relates to scientific research. Bibliometric studies of Antarctic science have provided a useful understanding of international and interdisciplinary collaboration, yet most research has focused on broad-scale analyses over recent time periods. Here, we take advantage of a ‘Goldilocks’ opportunity in the McMurdo Dry Valleys, an internationally important region of Antarctica and the largest ice-free region on the continent. The McMurdo Dry Valleys have attracted continuous and diverse scientific activity since 1958. It is a geographically confined region with limited access, making it possible to evaluate the influence of specific events and individuals. We trace the history of environmental science in this region using bibliometrics and social network analysis. Our results show a marked shift in focus from the geosciences to the biosciences, which mirrors wider trends in the history of science. Collaboration among individuals and academic disciplines increased through time, and the most productive scientists in the network are also the most interdisciplinary. Patterns of collaboration among disciplines resemble the biogeochemical relationships among respective landscape features, raising interesting questions about the role of the material environment in the development of scientific networks in the region, and the dynamic interaction with socio-cultural and political factors. Our focused, historical approach adds nuance to broad-scale bibliometric studies and could be applied to understanding the dynamics of scientific research in other regions of Antarctica and elsewhere.

10acritical physical geography10aenvironmental history10ahistory of science10ascience and technology studies10ascientometrics10avisual network analysis1 aChignell, Stephen, M.1 aHowkins, Adrian1 aGullett, Poppie1 aFountain, Andrew, G uhttps://polarresearch.net/index.php/polar/article/view/803703572nas a2200301 4500008004100000245010000041210006900141260001200210300001100222490000800233520264300241653002302884653001002907653002002917653002202937653002602959653001902985653001603004100002603020700002103046700002303067700001403090700002603104700002303130700001603153700002903169856007203198 2022 eng d00aPhotosynthetic adaptation to polar life: Energy balance, photoprotection and genetic redundancy0 aPhotosynthetic adaptation to polar life Energy balance photoprot c01/2022 a1535570 v2683 a

The persistent low temperature that characterize polar habitats combined with the requirement for light for all photoautotrophs creates a conundrum. The absorption of too much light at low temperature can cause an energy imbalance that decreases photosynthetic performance that has a negative impact on growth and can affect long-term survival. The goal of this review is to survey the mechanism(s) by which polar photoautotrophs maintain cellular energy balance, that is, photostasis to overcome the potential for cellular energy imbalance in their low temperature environments. Photopsychrophiles are photosynthetic organisms that are obligately adapted to low temperature (0-15 °C) but usually die at higher temperatures (≥20 °C). In contrast, photopsychrotolerant species can usually tolerate and survive a broad range of temperatures (5-40 °C). First, we summarize the basic concepts of excess excitation energy, energy balance, photoprotection and photostasis and their importance to survival in polar habitats. Second, we compare the photoprotective mechanisms that underlie photostasis and survival in aquatic cyanobacteria and green algae as well as terrestrial Antarctic and Arctic plants. We show that polar photopsychrophilic and photopsychrotolerant organisms attain energy balance at low temperature either through a regulated reduction in the efficiency of light absorption or through enhanced capacity to consume photosynthetic electrons by the induction of O2 as an alternative electron acceptor. Finally, we compare the published genomes of three photopsychrophilic and one photopsychrotolerant alga with five mesophilic green algae including the model green alga, Chlamydomonas reinhardtii. We relate our genomic analyses to photoprotective mechanisms that contribute to the potential attainment of photostasis. Finally, we discuss how the observed genomic redundancy in photopsychrophilic genomes may confer energy balance, photoprotection and resilience to their harsh polar environment. Primary production in aquatic, Antarctic and Arctic environments is dependent on diverse algal and cyanobacterial communities. Although mosses and lichens dominate the Antarctic terrestrial landscape, only two extant angiosperms exist in the Antarctic. The identification of a single ‘molecular key’ to unravel adaptation of photopsychrophily and photopsychrotolerance remains elusive. Since these photoautotrophs represent excellent biomarkers to assess the impact of global warming on polar ecosystems, increased study of these polar photoautotrophs remains essential.

10agenomic redundancy10alight10aphotoprotection10aphotopsychrophily10aphotopsychrotolerance10aPhotosynthesis10atemperature1 aHüner, Norman, P. A.1 aSmith, David, R.1 aCvetkovska, Marina1 aZhang, Xi1 aIvanov, Alexander, G.1 aSzyszka-Mroz, Beth1 aKalra, Isha1 aMorgan-Kiss, Rachael, M. uhttps://www.sciencedirect.com/science/article/pii/S017616172100196602944nas 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.1594002569nas a2200373 4500008004100000245008100041210006900122260004300191520135400234100001701588700001801605700002201623700002101645700002001666700003001686700002101716700002401737700002301761700001801784700002101802700002301823700002201846700002001868700002301888700002401911700001601935700002301951700002401974700002101998700001902019700001802038700002002056856011902076 2022 eng d00aTen scientific messages on risks and opportunities for life in the Antarctic0 aTen scientific messages on risks and opportunities for life in t bAntarctic Environments Portalc02/20223 a

Initiated by the SCAR scientific research programme “Antarctic Thresholds – Ecosystem Resilience and Adaptation” (AnT-ERA, 2013-2021), 26 experts synthesized knowledge on impacts and risks of climate-change on biological processes and ecosystem functions in the Antarctic. The ten main scientific messages that emerged addressed (1) accelerating marine and terrestrial biogeochemical cycles, (2) response to ocean acidification, (3) ecological changes in climate change hot spots, (4) unexpected dynamism of marine seafloor communities, (5) biodiversity shifts, (6) low temperature limitation of protein synthesis, (7) life intrinsically linked to changing sea ice conditions, (8) pollution, (9) genetically distinct terrestrial populations under threat, and (10) newly discovered habitats. Two-thirds of the literature included in this synthesis was published between 2010 and 2020 and only one-third was published earlier. The fast mounting, recent decadal evidence indicates various Antarctic biological communities now experience climate stress, or will experience such stress in the coming decades. The responses of organisms, ecosystem functions and services to environmental changes are complex and varied. Key knowledge gaps remain and need addressing to adequately assess future prospects for life in the Antarctic.

1 aGutt, Julian1 aIsla, Enrique1 aXavier, José, C.1 aAdams, Byron, J.1 aAhn, In‐Young1 aCheng, C.‐H., Christina1 aColesie, Claudia1 aCummings, Vonda, J.1 aGriffiths, Huw, J.1 aHogg, Ian, D.1 aMcIntyre, Trevor1 aMeiners, Klaus, M.1 aPearce, David, A.1 aPeck, Lloyd, S.1 aPiepenburg, Dieter1 aReisinger, Ryan, R.1 aSaba, Grace1 aSchloss, Irene, R.1 aSignori, Camila, N.1 aSmith, Craig, R.1 aVacchi, Marino1 aVerde, Cinzia1 aWall, Diana, H. uhttps://environments.aq/publications/ten-scientific-messages-on-risks-and-opportunities-for-life-in-the-antarctic/03115nas a2200517 4500008004100000245008300041210006900124260001200193520161800205653001501823653002101838653002601859653001901885653001301904653001701917653002401934653002301958653001701981653001201998100001702010700001802027700002202045700002102067700002002088700003002108700002102138700002402159700002102183700002302204700001502227700001802242700002102260700002302281700002202304700002002326700002302346700002402369700001602393700002302409700002402432700002102456700001902477700001802496700002002514856006302534 2021 eng d00aAntarctic ecosystems in transition – life between stresses and opportunities0 aAntarctic ecosystems in transition life between stresses and opp c06/20213 a

Important findings from the second decade of the 21st century on the impact of environmental change on biological processes in the Antarctic were synthesised by 26 international experts. Ten key messages emerged that have stakeholder‐relevance and/or a high impact for the scientific community. They address (i) altered biogeochemical cycles, (ii) ocean acidification, (iii) climate change hotspots, (iv) unexpected dynamism in seabed‐dwelling populations, (v) spatial range shifts, (vi) adaptation and thermal resilience, (vii) sea ice related biological fluctuations, (viii) pollution, (ix) endangered terrestrial endemism and (x) the discovery of unknown habitats. Most Antarctic biotas are exposed to multiple stresses and considered vulnerable to environmental change due to narrow tolerance ranges, rapid change, projected circumpolar impacts, low potential for timely genetic adaptation, and migration barriers. Important ecosystem functions, such as primary production and energy transfer between trophic levels, have already changed, and biodiversity patterns have shifted. A confidence assessment of the degree of ‘scientific understanding’ revealed an intermediate level for most of the more detailed sub‐messages, indicating that process‐oriented research has been successful in the past decade. Additional efforts are necessary, however, to achieve the level of robustness in scientific knowledge that is required to inform protection measures of the unique Antarctic terrestrial and marine ecosystems, and their contributions to global biodiversity and ecosystem services.

10aadaptation10abenthic dynamism10abiogeochemical cycles10aclimate change10ainvasion10anew habitats10aocean acidification10aPrimary production10arange shifts10asea ice1 aGutt, Julian1 aIsla, Enrique1 aXavier, José, C.1 aAdams, Byron, J.1 aAhn, In‐Young1 aCheng, C.‐H., Christina1 aColesie, Claudia1 aCummings, Vonda, J.1 adi Prisco, Guido1 aGriffiths, Huw, J.1 aHawes, Ian1 aHogg, Ian, D.1 aMcIntyre, Trevor1 aMeiners, Klaus, M.1 aPearce, David, A.1 aPeck, Lloyd, S.1 aPiepenburg, Dieter1 aReisinger, Ryan, R.1 aSaba, Grace1 aSchloss, Irene, R.1 aSignori, Camila, N.1 aSmith, Craig, R.1 aVacchi, Marino1 aVerde, Cinzia1 aWall, Diana, H. uhttps://onlinelibrary.wiley.com/doi/full/10.1111/brv.1267902885nas 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.ch1104166nas a2200565 4500008004100000022001400041245007900055210006900134260001200203300001100215490000700226520245300233653001802686653002702704653001902731653001902750653001202769653001202781653001502793653008902808653002002897100002302917700002502940700002602965700002702991700002103018700002503039700001703064700002203081700002903103700002603132700002403158700002603182700002403208700002103232700001603253700002703269700002403296700002303320700002203343700002403365700002303389700001503412700002203427700002103449700002203470700002603492700002403518856005803542 2021 eng d a2150-892500aConnectivity: Insights from the U.S. Long Term Ecological Research Network0 aConnectivity Insights from the US Long Term Ecological Research  c05/2021 ae034320 v123 a

Ecosystems across the United States are changing in complex and surprising ways. Ongoing demand for critical ecosystem services requires an understanding of the populations and communities in these ecosystems in the future. This paper represents a synthesis effort of the U.S. National Science Foundation-funded Long-Term Ecological Research (LTER) network addressing the core research area of “populations and communities.” The objective of this effort was to show the importance of long-term data collection and experiments for addressing the hardest questions in scientific ecology that have significant implications for environmental policy and management. Each LTER site developed at least one compelling case study about what their site could look like in 50–100 yr as human and environmental drivers influencing specific ecosystems change. As the case studies were prepared, five themes emerged, and the studies were grouped into papers in this LTER Futures Special Feature addressing state change, connectivity, resilience, time lags, and cascading effects. This paper addresses the “connectivity” theme and has examples from the Phoenix (urban), Niwot Ridge (alpine tundra), McMurdo Dry Valleys (polar desert), Plum Island (coastal), Santa Barbara Coastal (coastal), and Jornada (arid grassland and shrubland) sites. Connectivity has multiple dimensions, ranging from multi-scalar interactions in space to complex interactions over time that govern the transport of materials and the distribution and movement of organisms. The case studies presented here range widely, showing how land-use legacies interact with climate to alter the structure and function of arid ecosystems and flows of resources and organisms in Antarctic polar desert, alpine, urban, and coastal marine ecosystems. Long-term ecological research demonstrates that connectivity can, in some circumstances, sustain valuable ecosystem functions, such as the persistence of foundation species and their associated biodiversity or, it can be an agent of state change, as when it increases wind and water erosion. Increased connectivity due to warming can also lead to species range expansions or contractions and the introduction of undesirable species. Continued long-term studies are essential for addressing the complexities of connectivity. The diversity of ecosystems within the LTER network is a strong platform for these studies.

10aalpine tundra10aAntarctic polar desert10aarid grassland10aarid shrubland10acoastal10aestuary10asalt marsh10aSpecial Feature: Forecasting Earth’s Ecosystems with Long-Term Ecological Research10aurban ecosystem1 aIwaniec, David, M.1 aGooseff, Michael, N.1 aSuding, Katharine, N.1 aJohnson, David, Samuel1 aReed, Daniel, C.1 aPeters, Debra, P. C.1 aAdams, Byron1 aBarrett, John, E.1 aBestelmeyer, Brandon, T.1 aCastorani, Max, C. N.1 aCook, Elizabeth, M.1 aDavidson, Melissa, J.1 aGroffman, Peter, M.1 aHanan, Niall, P.1 aHuenneke, L1 aJohnson, Pieter, T. J.1 aMcKnight, Diane, M.1 aMiller, Robert, J.1 aOkin, Gregory, S.1 aPreston, Daniel, L.1 aRassweiler, Andrew1 aRay, Chris1 aSala, Osvaldo, E.1 aSchooley, Robert1 aSeastedt, Timothy1 aSpasojevic, Marko, J.1 aVivoni, Enrique, R. uhttps://onlinelibrary.wiley.com/doi/10.1002/ecs2.343202080nas a2200361 4500008004100000245006800041210006800109260001200177300000900189490000700198520108000205653001501285653001701300653001201317653001301329653001501342653000901357100001901366700002401385700001801409700002101427700002501448700002501473700002201498700002001520700001901540700001701559700002601576700001601602700001801618710002301636856005901659 2021 eng d00aDiatoms define a novel freshwater biogeography of the Antarctic0 aDiatoms define a novel freshwater biogeography of the Antarctic c01/2021 a1-130 v443 a

Terrestrial biota in the Antarctic are more globally distinct and highly structured biogeographically than previously believed, but information on biogeographic patterns and endemism in freshwater communities is largely lacking. We studied biogeographic patterns of Antarctic freshwater diatoms based on the analysis of species occurrences in a dataset of 439 lakes spread across the Antarctic realm. Highly distinct diatom floras, both in terms of composition and richness, characterize Continental Antarctica, Maritime Antarctica and the sub-Antarctic islands, with marked biogeographic provincialism in each region. A total of 44% of all species is estimated to be endemic to the Antarctic, and most of them are confined to a single biogeographic region. The level of endemism significantly increases with increasing latitude and geographic isolation. Our results have implications for conservation planning, and suggest that successful dispersal of freshwater diatoms to and within the Antarctic is limited, fostering the evolution of highly endemic diatom floras.

10aAntarctica10abiogeography10adiatoms10aendemism10afreshwater10alake1 aVerleyen, Elie1 aVan de Vijver, Bart1 aTytgat, Bjorn1 aPinseel, Eveline1 aHodgson, Dominic, A.1 aKopalová, Kateřina1 aChown, Steven, L.1 aVan Ranst, Eric1 aImura, Satoshi1 aKudoh, Sakae1 aVan Nieuwenhuyze, Wim1 aSabbe, Koen1 aVyverman, Wim1 aANTDIAT consortium uhttps://onlinelibrary.wiley.com/doi/10.1111/ecog.0537402809nas 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/10.1029/2020JG00609701659nas a2200193 4500008004100000022001300041245008600054210006900140260001200209300001100221490000700232520104000239100001401279700002301293700002901316700002601345700002201371856007201393 2021 eng d a2589004200aDraft genome sequence of the Antarctic green alga Chlamydomonas sp. UWO2410 aDraft genome sequence of the Antarctic green alga IChlamydomonas c2021-02 a1020840 v243 a

Antarctica is home to an assortment of psychrophilic algae, which have evolved various survival strategies for coping with their frigid environments. Here, we explore Antarctic psychrophily by examining the ∼212 Mb draft nuclear genome of the green alga Chlamydomonas sp. UWO241, which resides within the water column of a perennially ice-covered, hypersaline lake. Like certain other Antarctic algae, UWO241 encodes a large number (≥37) of ice-binding proteins, putatively originating from horizontal gene transfer. Even more striking, UWO241 harbors hundreds of highly similar duplicated genes involved in diverse cellular processes, some of which we argue are aiding its survival in the Antarctic via gene dosage. Gene and partial gene duplication appear to be an ongoing phenomenon within UWO241, one which might be mediated by retrotransposons. Ultimately, we consider how such a process could be associated with adaptation to extreme environments but explore potential non-adaptive hypotheses as well.

1 aZhang, Xi1 aCvetkovska, Marina1 aMorgan-Kiss, Rachael, M.1 aHüner, Norman, P. A.1 aSmith, David, Roy uhttps://www.sciencedirect.com/science/article/pii/S258900422100052302506nas 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/10.1029/2020JG00605201860nas a2200205 4500008004100000022001400041245015300055210006900208260001200277520112000289100002201409700002001431700002001451700002501471700001701496700002401513700002501537700002401562856006801586 2021 eng d a2378-224200aFrom the Heroic Age to today: What diatoms from Shackleton's Nimrod expedition can tell us about the ecological trajectory of Antarctic ponds0 aFrom the Heroic Age to today What diatoms from Shackletons iNimr c07/20213 a

Biological invasion and environmental change pose major threats to ecosystems. While long-term ecological change is commonly evaluated through sediment cores in lakes, it is generally not feasible for smaller ponds, and spatial resolution is limited. Here, we analyze pond diatom communities collected during Shackleton's Nimrod expedition at Cape Royds, Antarctica, to compare with the same waterbodies a century later. We find historical samples to be almost identical to modern counterparts, and provide no evidence of exotic introductions despite increasing human activity. However, a shift occurred in the pond nearest Shackleton's hut, Pony Lake, which was dominated by Luticola muticopsis a century ago, and was replaced by Craspedostauros laevissimus. Both are endemic species previously and currently present at Cape Royds, and we hypothesize that a shift in conductivity accompanying changing precipitation patterns may be responsible. Collectively, these results provide important data for assessing human and climate impacts among Antarctic lacustrine habitats.

1 aKohler, Tyler, J.1 aHowkins, Adrian1 aSokol, Eric, R.1 aKopalová, Kateřina1 aCox, Aneliya1 aDarling, Joshua, P.1 aGooseff, Michael, N.1 aMcKnight, Diane, M. uhttps://aslopubs.onlinelibrary.wiley.com/doi/10.1002/lol2.1020002615nas 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-Taylor01774nas a2200229 4500008004100000245011600041210006900157260001200226520104400238653001601282653001801298653001401316653001801330653002401348653001601372653001501388100001801403700001901421700002501440700002101465856005801486 2021 eng d00aHow long do population level field experiments need to be? Utilising data from the 40‐year‐old LTER network0 aHow long do population level field experiments need to be Utilis c02/20213 a

We utilise the wealth of data accessible through the 40‐year‐old Long‐Term Ecological Research (LTER) network to ask if aspects of the study environment or taxa alter the duration of research necessary to detect consistent results. To do this, we use a moving‐window algorithm. We limit our analysis to long‐term (> 10 year) press experiments recording organismal abundance. We find that studies conducted in dynamic abiotic environments need longer periods of study to reach consistent results, as compared to those conducted in more moderated environments. Studies of plants were more often characterised by spurious results than those on animals. Nearly half of the studies we investigated required 10 years or longer to become consistent, where all significant trends agreed in direction, and four studies (of 100) required longer than 20 years. Here, we champion the importance of long‐term data and bolster the value of multi‐decadal experiments in understanding, explaining and predicting long‐term trends.

10adata mining10aisothermality10along-term10amoving window10apopulation dynamics10atime series10atrajectory1 aCusser, Sarah1 aHelms, Jackson1 aBahlai, Christie, A.1 aHaddad, Nick, M. uhttps://onlinelibrary.wiley.com/doi/10.1111/ele.1371001609nas a2200157 4500008004100000022001400041245012700055210007100182260001200253520103400265100002401299700002501323700002401348700002101372856005801393 2021 eng d a0885-608700aLong‐term shifts in feedbacks among glacier surface change, melt generation, and runoff, McMurdo Dry Valleys, Antarctica0 aLong‐term shifts in feedbacks among glacier surface change melt  c07/20213 a

Glaciers of the McMurdo Dry Valleys (MDVs) Antarctica are the main source of streamflow in this polar desert. Because summer air temperatures hover near 0°C small changes in the energy balance strongly affect meltwater generation. Here we demonstrate that increased surface roughness, which alters the turbulent transfer of energy between the ice surface and atmosphere, yields a detectable increase in meltwater runoff. At low elevations on the glaciers, basin-like topography became significantly rougher over 13 years between repeat lidar surveys, yielding greater melt. In contrast, the smoother ice at higher elevation exhibited no detectable change in roughness. We pose a conceptual model of the cycle of glacier surface change as a result of climate forcing whereby glacier surfaces transition from being dominated by sublimation to becoming increasingly melt-dominated, which is reversible under prolonged cool periods. This research advances our understanding of warm season effects on polar glaciers.

1 aBergstrom, Anna, J.1 aGooseff, Michael, N.1 aFountain, Andrew, G1 aHoffman, Matthew uhttps://onlinelibrary.wiley.com/doi/10.1002/hyp.1429202981nas a2200253 4500008004100000022001400041245011200055210006900167260001200236300001400248490000700262520216600269653002102435653002602456653002602482100002802508700002202536700002202558700002102580700002202601700001802623700001502641856007102656 2021 eng d a1523-043000aThe magnitude and climate sensitivity of isotopic fractionation from ablation of Antarctic Dry Valley lakes0 amagnitude and climate sensitivity of isotopic fractionation from c12/2021 a352 - 3710 v533 a

There has been extensive research on the effects of evaporation on the isotopic ratio of lacustrine and marine water bodies; however, there are limited data on how ablation or sublimation from lake or sea ice influences the isotopic ratio of the residual water body. This is a challenging problem because there remains uncertainty on the magnitude of fractionation during sublimation and because ablation can involve mixed-phase processes associated with simultaneous sublimation, melting, evaporation, and refreezing. This uncertainty limits the ability to draw quantitative inferences on changing hydrological budgets from stable isotope records in arctic, Antarctic, and alpine lakes. Here, we use in situ measurements of the isotopic ratio of water vapor along with the gradient diffusion method to constrain the isotopic ratio of the ablating ice from two lakes in the McMurdo Dry Valleys, Antarctica. We find that during austral summer, the isotopic fractionation of ablation was insignificant during periods of boundary layer instability that are typical during midday when latent heat is highest. This implies that the loss of mass during these periods did not yield any isotopic enrichment to the residual lake mass. However, fractionation increased after midday when the boundary layer stabilized and the latent heat flux was small. This diurnal pattern was mirrored on synoptic timescales, when following warm and stable conditions latent heat flux was low and dominated by higher fractionation for a few days. We hypothesize that the shifting from negligible to large isotopic fractionation reflects the development and subsequent exhaustion of liquid water on the surface. The results illustrate the complex and nonlinear controls on isotopic fractionation from icy lakes, which implies that the isotopic enrichment from ablation could vary significantly over timescales relevant for changing lake volumes. Future work using water isotope fluxes for longer periods of time and over additional perennial and seasonal ice-covered lake systems is critical for developing models of the isotopic mass balance of arctic and Antarctic lake systems.

10aDry Valley lakes10aisotope fractionation10astable water isotopes1 aBellagamba, Anthony, W.1 aBerkelhammer, Max1 aWinslow, Luke, A.1 aDoran, Peter, T.1 aMyers, Krista, F.1 aDevlin, Shawn1 aHawes, Ian uhttps://www.tandfonline.com/doi/full/10.1080/15230430.2021.200189902224nas 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/2073-4425/12/3/42602579nas a2200397 4500008004100000022001300041245012700054210006900181260001200250300001100262490000600273520134500279653003401624653002501658653003101683653002701714653001801741653001401759100002201773700002401795700002201819700002301841700002301864700001401887700001901901700001601920700002101936700002701957700002601984700001602010700002402026700001602050700002102066700002202087856007202109 2021 eng d a2666900500aPatterns and trends of organic matter processing and transport: Insights from the US Long-term Ecological Research Network0 aPatterns and trends of organic matter processing and transport I c12/2021 a1000250 v23 a

Organic matter (OM) dynamics determine how much carbon is stored in ecosystems, a service that modulates climate. We synthesized research from across the US Long-Term Ecological Research (LTER) Network to assemble a conceptual model of OM dynamics that is consistent with inter-disciplinary perspectives and emphasizes vulnerability of OM pools to disturbance. Guided by this conceptual model, we identified unanticipated patterns and long-term trends in processing and transport of OM emerging from terrestrial, freshwater, wetland, and marine ecosystems. Cross-ecosystem synthesis combined with a survey of researchers revealed several themes: 1) strong effects of climate change on OM dynamics, 2) surprising patterns in OM storage and dynamics resulting from coupling with nutrients, 3) characteristic and often complex legacies of land use and disturbance, 4) a significant role of OM transport that is often overlooked in terrestrial ecosystems, and 5) prospects for reducing uncertainty in forecasting OM dynamics by incorporating the chemical composition of OM. Cross-fertilization of perspectives and approaches across LTER sites and other research networks can stimulate the comprehensive understanding required to support large-scale characterizations of OM budgets and the role of ecosystems in regulating global climate.

10acoupled biogeochemical cycles10across-site synthesis10aorganic matter composition10aorganic matter storage10astabilization10atransport1 aHarms, Tamara, K.1 aGroffman, Peter, M.1 aAluwihare, Lihini1 aCraft, Christopher1 aWieder, William, R1 aHobbie, S1 aBaer, Sara, G.1 aBlair, J.M.1 aFrey, Serita, D.1 aRemucal, Christina, K.1 aRudgers, Jennifer, A.1 aCollins, SL1 aKominoski, John, S.1 aBall, Becky1 aPriscu, John, C.1 aBarrett, John, E. uhttps://www.sciencedirect.com/science/article/pii/S266690052100025301817nas a2200169 4500008004100000245017100041210006900212260001200281300001300293490000700306520116600313100002601479700002001505700002001525700002401545856007801569 2021 eng d00aResearch sites get closer to field camps over time: Informing environmental management through a geospatial analysis of science in the McMurdo Dry Valleys, Antarctica0 aResearch sites get closer to field camps over time Informing env c11/2021 ae02579500 v163 a

As in many parts of the world, the management of environmental science research in Antarctica relies on cost-benefit analysis of negative environmental impact versus positive scientific gain. Several studies have examined the environmental impact of Antarctic field camps, but very little work looks at how the placement of these camps influences scientific research. In this study, we integrate bibliometrics, geospatial analysis, and historical research to understand the relationship between field camp placement and scientific production in the McMurdo Dry Valleys of East Antarctica. Our analysis of the scientific corpus from 1907–2016 shows that, on average, research sites have become less dispersed and closer to field camps over time. Scientific output does not necessarily correspond to the number of field camps, and constructing a field camp does not always lead to a subsequent increase in research in the local area. Our results underscore the need to consider the complex historical and spatial relationships between field camps and research sites in environmental management decision-making in Antarctica and other protected areas.

1 aChignell, Stephen, M.1 aMyers, Madeline1 aHowkins, Adrian1 aFountain, Andrew, G uhttps://journals.plos.org/plosone/article?id=10.1371/journal.pone.025795002603nas a2200217 4500008004100000022001400041245012400055210006900179260001200248520186200260653001502122653002702137653001902164653002102183653001502204100002202219700002502241700002402266700002602290856006902316 2021 eng d a2169-895300aThe role of hyporheic connectivity in determining nitrogen availability: Insights from an intermittent Antarctic stream0 arole of hyporheic connectivity in determining nitrogen availabil c04/20223 a

Due to widespread manipulation of nitrogen (N), much research has focused on processes controlling the fate of anthropogenic N in streams. Yet, in a variety of oligotrophic systems, N fixed by periphyton is a significant driver of ecosystem metabolism. Due to difficulties partitioning allochthonous and autochthonous sources, there is limited information regarding how the latter is processed. Autochthonous N may be particularly important in alpine, arid, or polar environments. We test the hypothesis that the availability of remineralized autochthonous N is controlled by connectivity between the hyporheic zone and main channel due to the contrasting biogeochemical functions of benthic autotrophs (including N‐fixing Nostoc) and hyporheic heterotrophs in an intermittent Antarctic stream. There, we collected surface water and hyporheic water concurrently at 4‐6 hour intervals over a 32.5‐hr period during one flow season and opportunistically throughout a second. Hyporheic water had 7 to 30 times greater nitrate‐N concentrations relative to surface water across all flow conditions. In contrast, ammonium concentrations were generally lower, although similar among locations. Additionally, nitrate in hyporheic water was positively correlated with silica, an indicator of hyporheic residence time. A laboratory assay confirmed prior inferences that hyporheic microbial communities possess the functional potential to perform nitrification. Together, these findings suggest that remineralized autochthonous N accumulates in the hyporheic zone even as streamflow varies and likely subsidizes stream N availability—which supports prior inferences from N stable isotope data at this site. These results highlight the importance of hyporheic connectivity in controlling autochthonous N cycling and availability in streams.

10aAntarctica10aautochthonous nitrogen10ahyporheic zone10anitrogen cycling10astreamflow1 aSingley, Joel, G.1 aGooseff, Michael, N.1 aMcKnight, Diane, M.1 aHinckley, Eve-Lyn, S. uhttps://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021JG00630903417nas a2200193 4500008004100000245006200041210006200103260006200165490000800227520280000235653001503035653001903050653002103069653001203090100002203102700002603124700002503150856004803175 2021 eng d00aStream corridor connectivity controls on nitrogen cycling0 aStream corridor connectivity controls on nitrogen cycling aBoulder, CO, USAbUniversity of Colorado Boulderc05/20210 vPhD3 a

As water flows downstream, it is transported to and from environments that surround the visible stream. Along with surface water, these laterally and vertically connected environments comprise the stream corridor. Stream corridor connectivity influences many ecosystem services, including retention of excess nutrients. The subsurface area where stream water and groundwater mixes—the hyporheic zone—represents one of the most biogeochemically active parts of stream corridors.

The goal of my research is to advance understanding of how connectivity between different parts of a stream corridor controls the availability and retention of nitrogen (N), a nutrient that can limit primary productivity (low-N) and negatively impact water quality (excess N). First, I developed and applied a new machine learning method to objectively characterize the extent and variability of hyporheic exchange in terms of statistically unique functional zones using geophysical data. In applying this method to a benchmark dataset, I found that hyporheic extent does not scale uniformly with streamflow and that changes in the heterogeneity of connectivity differ over small (<10 m) distances. Next, I leveraged the relative simplicity of ephemeral streams of the McMurdo Dry Valleys (MDVs), Antarctica, to isolate stream corridor processes that influence the fate of N. Through intensive field sampling campaigns, I found that the hyporheic zone can be a persistent source of N even in this low nutrient environment. Next, I combined historic sample data and remote sensing analysis to estimate how much N is stored in an MDV stream corridor. My results indicate that up to 103 times more N is stored in this system than is exported each year, with most of this storage in the shallow (< 10 cm) hyporheic zone. Lastly, I examined 25 years of data for 10 streams to assess how stream corridor processes control concentration-discharge relationships. I found that in the absence of hillslope connectivity, stream corridor processes alone can maintain chemostasis – relatively small concentration changes with large fluctuations in streamflow – of both geogenic solutes and primary nutrients. My analysis also revealed that solutes subject to greater control by biological processes exhibit more variability within chemostatic relationships than weathering solutes that are only minimally influenced by biota.

Altogether, this research advances understanding of processes that are difficult to measure or are often overlooked in typical studies of temperate stream corridors. My findings provide insight into the surprising ways in which N is mobilized, transformed, and retained due to stream corridor connectivity in intermittent stream systems with few N inputs.

10aAntarctica10ahyporheic zone10anitrogen cycling10astreams1 aSingley, Joel, G.1 aHinckley, Eve-Lyn, S.1 aGooseff, Michael, N. uhttps://www.proquest.com/docview/257259312704249nas a2200253 4500008004100000245009000041210006900131260001200200490000600212520350100218653002003719653002003739653001303759100001903772700002003791700002203811700002403833700002503857700001903882700001203901700001703913700002103930856004403951 2020 eng d00aChange in Pictures: Creating best practices in archiving ecological imagery for reuse0 aChange in Pictures Creating best practices in archiving ecologic c09/20200 v43 a

The research data repository of the Environmental Data Initiative (EDI) is building on over 30 years of data curation research and experience in the National Science Foundation-funded US Long-Term Ecological Research (LTER) Network. It provides mature functionalities, well established workflows, and now publishes all ‘long-tail’ environmental data. High quality scientific metadata are enforced through automatic checks against community developed rules and the Ecological Metadata Language (EML) standard. Although the EDI repository is far along in making its data findable, accessible, interoperable, and reusable (FAIR), representatives from EDI and the LTER are developing best practices for the edge cases in environmental data publishing. One of these is the vast amount of imagery taken in the context of ecological research, ranging from wildlife camera traps to plankton imaging systems to aerial photography. Many images are used in biodiversity research for community analyses (e.g., individual counts, species cover, biovolume, productivity), while others are taken to study animal behavior and landscape-level change.

Some examples from the LTER Network include: using photos of a heron colony to measure provisioning rates for chicks (Clarkson and Erwin 2018) or identifying changes in plant cover and functional type through time (Peters et al. 2020). Multi-spectral images are employed to identify prairie species. Underwater photo quads are used to monitor changes in benthic biodiversity (Edmunds 2015). Sosik et al. (2020) used a continuous Imaging FlowCytobot to identify and measure phyto- and microzooplankton. Cameras at McMurdo Dry Valleys assess snow and ice cover on Antarctic lakes allowing estimation of primary production (Myers 2019).

It has been standard practice to publish numerical data extracted from images in EDI; however, the supporting imagery generally has not been made publicly available. Our goal in developing best practices for documenting and archiving these images is for them to be discovered and re-used. Our examples demonstrate several issues. The research questions, and hence, the image subjects are variable. Images frequently come in logical sets of time series. The size of such sets can be large and only some images may be contributed to a dedicated specialized repository. Finally, these images are taken in a larger monitoring context where many other environmental data are collected at the same time and location.

Currently, a typical approach to publishing image data in EDI are packages containing compressed (ZIP or tar) files with the images, a directory manifest with additional image-specific metadata, and a package-level EML metadata file. Images in the compressed archive may be organized within directories with filenames corresponding to treatments, locations, time periods, individuals, or other grouping attributes. Additionally, the directory manifest table has columns for each attribute. Package-level metadata include standard coverage elements (e.g., date, time, location) and sampling methods. This approach of archiving logical ‘sets’ of images reduces the effort of providing metadata for each image when most information would be repeated, but at the expense of not making every image individually searchable. The latter may be overcome if the provided manifest contains standard metadata that would allow searching and automatic integration with other images.

10adata repository10aecological data10ametadata1 aGries, Corinna1 aBeaulieu, Stace1 aBrown, Renée, F.1 aGastil-Buhl, Gastil1 aElmendorf, Sarah, C.1 aHsieh, Hsun-Yi1 aKui, Li1 aMaurer, Greg1 aPorter, John, H. uhttps://biss.pensoft.net/article/59082/02207nas a2200205 4500008004100000245010800041210006900149260001200218520152500230100001601755700001401771700002301785700001901808700002201827700001401849700001901863700002101882700002901903856006901932 2020 eng d00aChlamydomonas sp. UWO 241 exhibits high cyclic electron flow and rewired metabolism under high salinity0 aChlamydomonas sp UWO 241 exhibits high cyclic electron flow and  c03/20203 a

The Antarctic green alga Chlamydomonas sp. UWO 241 (UWO 241) is adapted to permanent low temperatures, hypersalinity, and extreme shade. one of the most striking phenotypes of UWO 241 is an altered photosystem I (PSI) organization and constitutive PSI cyclic electron flow (CEF). To date, little attention has been paid to CEF during long-term stress acclimation, and the consequences of sustained CEF in UWO 241 are not known. In this study, we combined photobiology, proteomics, and metabolomics to understand the underlying role of sustained CEF in high salinity stress acclimation. High salt-grown UWO 241 exhibited increased thylakoid proton motive flux and an increased capacity for non-photochemical quenching. Under high salt, a significant proportion of the upregulated enzymes were associated with the Calvin Benson Bassham Cycle, carbon storage metabolism, and protein translation. Two key enzymes of the Shikimate pathway, DAHP synthase and chorismate synthase, were also upregulated, as well as indole-3-glycerol phosphate synthase, an enzyme involved in the biosynthesis of L-tryptophan and indole acetic acid. In addition, several compatible solutes (glycerol, proline, and sucrose) accumulated to high levels in high salt-grown UWO 241 cultures. We suggest that UWO 241 maintains constitutively high CEF through the associated PSI-cytochrome b6f supercomplex to support robust growth and strong photosynthetic capacity under a constant growth regime of low temperatures and high salinity.

1 aKalra, Isha1 aWang, Xin1 aCvetkovska, Marina1 aJeong, Jooyeon1 aMcHargue, William1 aZhang, Ru1 aHüner, Norman1 aYuan, Joshua, S.1 aMorgan-Kiss, Rachael, M. uhttp://www.plantphysiol.org/content/early/2020/04/03/pp.19.0128002447nas a2200181 4500008004100000245007900041210006900120260001200189490000700201520187300208100002002081700002602101700002002127700002402147700001902171700002102190856005402211 2020 eng d00aA digital archive of human activity in the McMurdo Dry Valleys, Antarctica0 adigital archive of human activity in the McMurdo Dry Valleys Ant c05/20200 v123 a

Over the last half century, the McMurdo Dry Valleys (MDV) of East Antarctica have become a globally important site for scientific research and environmental monitoring. Historical data can make important contributions to current research activities and environmental management in Antarctica but tend to be widely scattered and difficult to access. We address this need in the MDV by compiling over 5000 historical photographs, sketches, maps, oral interviews, publications, and other archival resources into an online digital archive. The data have been digitized and georeferenced using a standardized metadata structure, which enables intuitive searches and data discovery via an online interface. The ultimate aim of the archive is to create as comprehensive as possible a record of human activity in the MDV to support ongoing research, management, and conservation efforts. This is a valuable tool for scientists seeking to understand the dynamics of change in lakes, glaciers, and other physical systems, as well as humanistic inquiry into the history of the Southern Continent. In addition to providing benchmarks for understanding change over time, the data can help target field sampling for studies working under the assumption of a pristine landscape by enabling researchers to identify the date and extent of past human activities. The full database is accessible via a web browser-based interface hosted by the McMurdo Long Term Ecological Research site: http://mcmurdohistory.lternet.edu/ (last access: 5 May 2020). The complete metadata data for all resources in the database are also available at the Environmental Data Initiative: https://doi.org/10.6073/pasta/6744cb28a544fda827805db123d36557 (Howkins et al., 2019).

1 aHowkins, Adrian1 aChignell, Stephen, M.1 aGullett, Poppie1 aFountain, Andrew, G1 aBrett, Melissa1 aPreciado, Evelin uhttps://www.earth-syst-sci-data.net/12/1117/2020/02314nas a2200265 4500008004100000245012500041210006900166260001200235490000700247520147000254653001501724653001101739653001701750653001801767653001101785653004001796100002201836700001501858700002301873700002201896700002401918700002101942700002101963856006401984 2020 eng d00aEnergetic and environmental constraints on the community structure of benthic microbial mats in Lake Fryxell, Antarctica0 aEnergetic and environmental constraints on the community structu c02/20200 v963 a

Ecological communities are regulated by the flow of energy through environments. Energy flow is typically limited by access to photosynthetically active radiation (PAR) and oxygen concentration (O2). The microbial mats growing on the bottom of Lake Fryxell, Antarctica, have well-defined environmental gradients in PAR and (O2). We analyzed the metagenomes of layers from these microbial mats to test the extent to which access to oxygen and light controls community structure. We found variation in the diversity and relative abundances of Archaea, Bacteria and Eukaryotes across three (O2) and PAR conditions: high (O2) and maximum PAR, variable (O2) with lower maximum PAR, and low (O2) and maximum PAR. We found distinct communities structured by the optimization of energy use on a millimeter-scale across these conditions. In mat layers where (O2) was saturated, PAR structured the community. In contrast, (O2) positively correlated with diversity and affected the distribution of dominant populations across the three habitats, suggesting that meter-scale diversity is structured by energy availability. Microbial communities changed across covarying gradients of PAR and (O2). The comprehensive metagenomic analysis suggests that the benthic microbial communities in Lake Fryxell are structured by energy flow across both meter- and millimeter-scales.

10aAntarctica10aenergy10aLake Fryxell10amicrobial mat10aOxygen10aPhotosynthetically Active Radiation1 aDillon, Megan, L.1 aHawes, Ian1 aJungblut, Anne, D.1 aMackey, Tyler, J.1 aEisen, Jonathan, A.1 aDoran, Peter, T.1 aSumner, Dawn, Y. uhttps://academic.oup.com/femsec/article/96/2/fiz207/569719602205nas a2200205 4500008004100000245012400041210006900165260001200234300001300246490000700259520150700266100002201773700001501795700002301810700002201833700002401855700002101879700002101900856007801921 2020 eng d00aEnvironmental control on the distribution of metabolic strategies of benthic microbial mats in Lake Fryxell, Antarctica0 aEnvironmental control on the distribution of metabolic strategie c04/2020 ae02310530 v153 a

Ecological theories posit that heterogeneity in environmental conditions greatly affects community structure and function. However, the degree to which ecological theory developed using plant- and animal-dominated systems applies to microbiomes is unclear. Investigating the metabolic strategies found in microbiomes are particularly informative for testing the universality of ecological theories because microorganisms have far wider metabolic capacity than plants and animals. We used metagenomic analyses to explore the relationships between the energy and physicochemical gradients in Lake Fryxell and the metabolic capacity of its benthic microbiome. Statistical analysis of the relative abundance of metabolic marker genes and gene family diversity shows that oxygenic photosynthesis, carbon fixation, and flavin-based electron bifurcation differentiate mats growing in different environmental conditions. The pattern of gene family diversity points to the likely importance of temporal environmental heterogeneity in addition to resource gradients. Overall, we found that the environmental heterogeneity of photosynthetically active radiation (PAR) and oxygen concentration ([O2]) in Lake Fryxell provide the framework by which metabolic diversity and composition of the community is structured, in accordance with its phylogenetic structure. The organization of the resulting microbial ecosystems are consistent with the maximum power principle and the species sorting model.

1 aDillon, Megan, L.1 aHawes, Ian1 aJungblut, Anne, D.1 aMackey, Tyler, J.1 aEisen, Jonathan, A.1 aDoran, Peter, T.1 aSumner, Dawn, Y. uhttps://journals.plos.org/plosone/article?id=10.1371/journal.pone.023105302303nas 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/2020/08/19/200792511703683nas 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/s41597-020-0437-302112nas a2200229 4500008004100000245006600041210006600107260001200173490000700185520130800192653001901500653001901519653002001538653002301558653001301581100002801594700002201622700002201644700002401666700002301690856016901713 2020 eng d00aModeling present and future ice covers in two Antarctic lakes0 aModeling present and future ice covers in two Antarctic lakes c02/20200 v663 a

Antarctic lakes with perennial ice covers provide the opportunity to investigate in-lake processes without direct atmospheric interaction, and to study their ice-cover sensitivity to climate condi- tions. In this study, a numerical model – driven by radiative, atmospheric and turbulent heat fluxes from the water body beneath the ice cover – was implemented to investigate the impact of climate change on the ice covers from two Antarctic lakes: west lobe of Lake Bonney (WLB) and Crooked Lake. Model results agreed well with measured ice thicknesses of both lakes (WLB – RMSE= 0.11 m over 16 years of data; Crooked Lake – RMSE= 0.07 m over 1 year of data), and had acceptable results with measured ablation data at WLB (RMSE= 0.28 m over 6 years). The differences between measured and modeled ablation occurred because the model does not consider interannual variability of the ice optical properties and seasonal changes of the lake’s thermal structure. Results indicate that projected summer air temperatures will increase the ice-cover annual melting in WLB by 2050, but that the ice cover will remain peren- nial through the end of this century. Contrarily, at Crooked Lake the ice cover becomes ephem- eral most likely due to the increase in air temperatures.

10aclimate change10aenergy balance10aice and climate10aice-sheet modeling10alake ice1 aEcheverría, Sebastián1 aHausner, Mark, B.1 aBambach, Nicolás1 aVicuña, Sebastián1 aSuárez, Francisco uhttps://www.cambridge.org/core/journals/journal-of-glaciology/article/modeling-present-and-future-ice-covers-in-two-antarctic-lakes/9306439ADD5492BC05F3BAF0E076B1C301899nas a2200133 4500008004100000245012300041210007100164260001200235520137500247100003101622700002101653700002301674856006801697 2020 eng d00aPicocyanobacterial cells in near‐surface air above terrestrial and freshwater substrates in Greenland and Antarctica0 aPicocyanobacterial cells in near‐surface air above terrestrial a c03/20203 a

Bioaerosols are an important component of the total atmospheric aerosol load, with implications for human health, climate feedbacks, and the distribution and dispersal of microbial taxa. Bioaerosols are sourced from marine, freshwater, and terrestrial surfaces, with different mechanisms potentially responsible for releasing biological particles from these substrates. Little is known about the production of freshwater and terrestrial bioaerosols in polar regions. We used portable collection devices to test for the presence of picocyanobacterial aerosols above freshwater and soil substrates in the southwestern Greenland tundra and the McMurdo Dry Valleys of Antarctica. We show that picocyanobacterial cells are present in the near‐surface air at concentrations ranging from 2,431 to 28,355 cells m^−3 of air, with no significant differences among substrates or between polar regions. Our concentrations are lower than those measured using the same methods in temperate ecosystems. We suggest that aerosolization is an important process linking terrestrial and aquatic ecosystems in these polar environments, and that future work is needed to explore aerosolization mechanisms and taxon‐specific aerosolization rates. Our study is a first step toward understanding the production of bioaerosols in extreme environments dominated by microbial life.

1 aTrout‐Haney, Jessica, V.1 aHeindel, Ruth, C1 aVirginia, Ross, A. uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/1758-2229.1283202115nas a2200181 4500008004100000245013800041210006900179260001200248520140900260653001501669653001701684653003601701653002901737653004501766100002601811700002001837856007601857 2020 eng d00aThe rise of technocratic environmentalism: the United States, Antarctica, and the globalisation of the environmental impact statement0 arise of technocratic environmentalism the United States Antarcti c05/20203 a

Environmental impact statements (EISs), and the related environmental impact assessments (EIAs) which precede them, have become central elements of environmental management, governance, and policy worldwide since their introduction in the United States in 1970. Assessing environmental impact has a particular force and centrality within modern Antarctic environmental management and governance too. This article investigates the ways in which the United States used EISs and EIAs in Antarctica between 1970 and 1982 – during their first decade of existence in US law and during a geopolitically and scientifically vibrant decade in Antarctic affairs – as a way of illuminating the broader conceptual and historical aspects of this central, though understudied, environmental governance tool and framework. We historicise and draw attention to the EIS – individually, as a regulatory genre, and as a genre that articulates regional, global and planetary environments – as highly influential and powerful documents demanding attention from environmental historians and historical geographers. We argue that the prominence of EISs in Antarctica arose because they appealed to top-down, process-oriented approaches favoured in Antarctic governance – a technocratic environmentalism – and because of their spatial elements, particularly their tendency to upscaling.

10aAntarctica10aConservation10aEnvironmental impact statements10aEnvironmental protection10aNational Environmental Policy Act (NEPA)1 aAntonello, Alessandro1 aHowkins, Adrian uhttps://www.sciencedirect.com/science/article/abs/pii/S030574882030027X02966nas 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/full02353nas 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/s42003-018-0274-502475nas a2200229 4500008004100000020002200041245008100063210006900144260004400213300001300257520171900270653001201989653002202001653002502023653003102048653001702079100001502096700002102111700002302132700002402155856006602179 2019 eng d a978-3-030-16775-200aComplex Structure but Simple Function in Microbial Mats from Antarctic Lakes0 aComplex Structure but Simple Function in Microbial Mats from Ant aChambSpringer International Publishing a91 - 1203 a

Microbial mats growing under the permanent ice cover of Antarctic lakes occupy an exceptionally low-disturbance regime. Constant temperature, the absence of bioturbation or physical disturbance from wind action or ice formation allow mats to accumulate, as annual growth layers, over many decades or even centuries. In so doing they often assume decimetre scale, three-dimensional morphologies such as elaborate pinnacle structures and conical mounds. Here we combine existing and new information to describe microbial structures in three Antarctic lakes—simple prostrate mats in Lake Hoare, emergent cones in Lake Untersee and elaborate pinnacles in Lake Vanda. We attempt to determine whether structures emerge simply from uncoordinated organism-environment interactions or whether they represent an example of “emergent complexity”, within which some degree of self-organisation occurs to confer a holistic functional advantage to component organisms. While some holistic advantages were evident from the structures—the increase in surface area allows greater biomass and overall productivity and nutrient exchange with overlying water—the structures could also be understood in terms of potential interactions between individuals, their orientation and their environment. The data lack strong evidence of coordinated behaviour directed towards holistic advantages to the structure, though hints of coordinated behaviour are present as non-random distributions of structural elements. The great size of microbial structures in Antarctic lakes, and their relatively simple community composition, makes them excellent models for more focused research on microbial cooperation.

10abiofilm10amicrobial ecology10amicrobial structures10aself-organising structures10astromatolite1 aHawes, Ian1 aSumner, Dawn, Y.1 aJungblut, Anne, D.1 aHurst, Christon, J. uhttps://link.springer.com/chapter/10.1007/978-3-030-16775-2_402367nas a2200205 4500008004100000245011400041210006900155260001200224300001400236490000800250520166200258100002501920700002701945700002801972700002602000700002002026700002002046700002102066856007402087 2019 eng d00aDifferential incorporation of bacteria, organic matter, and inorganic ions into lake ice during ice formation0 aDifferential incorporation of bacteria organic matter and inorga c02/2019 a585 - 6000 v1243 a

The segregation of bacteria, inorganic solutes, and total organic carbon between liquid water and ice during winter ice formation on lakes can significantly influence the concentration and survival of microorganisms in icy systems, and their roles in biogeochemical processes. Our study quantifies the distributions of bacteria and solutes between liquid and solid water phases during progressive freezing. We simulated lake ice formation in mesocosm experiments using water from perennially (Antarctica) and seasonally (Alaska and Montana, USA) ice covered lakes. We then computed concentration factors and effective segregation coefficients, which are parameters describing the incorporation of bacteria and solutes into ice. Experimental results revealed that, contrary to major ions, bacteria were readily incorporated into ice and did not concentrate in the liquid phase. The organic matter incorporated into the ice was labile, amino acid-like material, differing from the humic-like compounds that remained in the liquid phase. Results from a control mesocosm experiment (dead bacterial cells) indicated that viability of bacterial cells did not influence the incorporation of free bacterial cells into ice, but did have a role in the formation and incorporation of bacterial aggregates. Together, these findings demonstrate that bacteria, unlike other solutes, were preferentially incorporated into lake-ice during our freezing experiments, a process controlled mainly by the initial solute concentration of the liquid water source, regardless of cell viability.

1 aSantibáñez, Pamela1 aMichaud, Alexander, B.1 aVick-Majors, Trista, J.1 aD’Andrilli, Juliana1 aChiuchiolo, Amy1 aHand, Kevin, P.1 aPriscu, John, C. uhttps://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018JG00482501931nas 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.html02611nas a2200253 4500008004100000245011600041210006900157260001200226520177500238653001202013653002502025653003202050653001402082653002402096100002102120700002202141700002802163700002102191700002302212700002102235700001502256700002302271856006302294 2019 eng d00aEnvironmental controls on bacteriohopanepolyol profiles of benthic microbial mats from Lake Fryxell, Antarctica0 aEnvironmental controls on bacteriohopanepolyol profiles of benth c07/20193 a

Bacteriohopanepolyols (BHPs) are pentacyclic triterpenoid lipids that contribute to the structural integrity and physiology of some bacteria. Because some BHPs originate from specific classes of bacteria, BHPs have potential as taxonomically and environmentally diagnostic biomarkers. For example, a stereoisomer of bacteriohopanetetrol (informally BHT II) has been associated with anaerobic ammonium oxidation (anammox) bacteria and suboxic to anoxic marine environments where anammox is active. As a result, the detection of BHT II in the sedimentary record and fluctuations in the relative abundance of BHT II may inform reconstructions of nitrogen cycling and ocean redox changes through the geological record. However, there are uncertainties concerning the sources of BHT II and whether or not BHT II is produced in abundance in non‐marine environments, both of which are pertinent to interpretations of BHT II signatures in sediments. To address these questions, we investigate the BHP composition of benthic microbial mats from Lake Fryxell, Antarctica. Lake Fryxell is a perennially ice‐covered lake with a sharp oxycline in a density‐stabilized water column. We describe the diversity and abundance of BHPs in benthic microbial mats across a transect from oxic to anoxic conditions. Generally, BHP abundances and diversity vary with the morphologies of microbial mats, which were previously shown to reflect local environmental conditions, such as irradiance and oxygen and sulfide concentrations. BHT II was identified in mats that exist within oxic to anoxic portions of the lake. However, anammox bacteria have yet to be identified in Lake Fryxell. We examine our results in the context of BHPs as biomarkers in modern and ancient environments.

10aanammox10abacteriohopanepolyol10abacteriohopanetetrol isomer10abiomarker10aMcMurdo Dry Valleys1 aMatys, Emily, D.1 aMackey, Tyler, J.1 aGrettenberger, Christen1 aMueller, Elliott1 aJungblut, Anne, D.1 aSumner, Dawn, Y.1 aHawes, Ian1 aSummons, Roger, E. uhttps://onlinelibrary.wiley.com/doi/full/10.1111/gbi.1235302449nas a2200169 4500008004100000245008400041210006900125260001200194490000700206520189300213100003002106700002102136700002202157700001502179700002302194856006202217 2019 eng d00aIn a PICL: The sedimentary deposits and facies of perennially ice-covered lakes0 aIn a PICL The sedimentary deposits and facies of perennially ice c04/20190 v663 a

Perennially ice‐covered lakes can have significantly different facies than open‐water lakes because sediment is transported onto the ice, where it accumulates, and sand grains preferentially melt through to be deposited on the lake floor. To characterize the facies in these lakes, sedimentary deposits from five Antarctic perennially ice‐covered lakes were described using lake‐bottom observations, underwater video and images, and sediment cores. One lake was dominated by laminated microbial mats and mud (derived from an abutting glacier), with disseminated sand and rare gravel. The other four lakes were dominated by laminated microbial mats and moderately well to moderately sorted medium to very coarse sand with sparse granules and pebbles; they contained minor interstitial or laminated mud (derived from streams and abutting glaciers). The sand was disseminated or localized in mounds and 1 m to more than 10 m long elongate ridges. Mounds were centimetres to metres in diameter; conical, elongate or round in shape; and isolated or deposited near or on top of one another. Sand layers in the mounds had normal, inverse, or no grading. Nine mixed mud and sand facies were defined for perennially ice‐covered lakes based on the relative proportion of mud to sand and the style of sand deposition. While perennially ice‐covered lake facies overlap with other ice‐influenced lakes and glaciomarine facies, they are characterized by a paucity of grains coarser than granules, a narrow range in sand grain sizes, and inverse grading in the sand mounds. These facies can be used to infer changes in ice cover through time and to identify perennially ice‐covered lakes in the rock record. Ancient perennially ice‐covered lakes are expected on Earth and Mars, and their characterization will provide new insights into past climatic conditions and habitability.

1 aRivera-Hernandez, Frances1 aSumner, Dawn, Y.1 aMackey, Tyler, J.1 aHawes, Ian1 aAndersen, Dale, T. uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/sed.1252202454nas a2200289 4500008004100000022001400041245011100055210006900166260001200235300001600247490000700263520153600270653001501806653001501821653003701836653002101873653002401894653003201918100002001950700001601970700002601986700002102012700001402033700002302047700001502070856007902085 2019 eng d a1558-842400aMeteorological connectivity from regions of high biodiversity within the McMurdo Dry Valleys of Antarctica0 aMeteorological connectivity from regions of high biodiversity wi c11/2019 a2437 - 24520 v583 a

Meteorological connectivity between biological hot spots of the McMurdo Dry Valleys (MDVs) of Antarctica is thought to play a role in species distribution and abundance through the aeolian transport of bioaerosols. Understanding the potential role of such meteorological connectivity requires an understanding of near-surface wind flow within and between valley airsheds. To address this, we applied Lagrangian wind trajectory modeling to mesoscale (spatial resolution of ~1 km) weather model output to predict connectivity pathways, focusing on regions of high biodiversity. Our models produce maps of a likelihood metric of wind connectivity that demonstrate the synoptic and mesoscale dependence of connections between local, near-local, and nonlocal areas on wind transport, modulated by synoptic weather and topographic forcing. These connectivity areas can have spatial trends modulated by the synoptic weather patterns and locally induced topographically forced winds. This method is transferrable to other regions of Antarctica for broader terrestrial, coastal, and offshore ecological connectivity research. Also, our analysis and methods can inform better placement of aeolian dust and bioaerosol samplers in the McMurdo Dry Valleys, provide preliminary guidelines behind the meteorological controls of sediment transport and smaller particle distribution, and present quantifiable knowledge informing new hypotheses around the potential of wind acting as a physical driver for biological connectivity in the MDVs.

10aAntarctica10aatmosphere10abiosphere-atmosphere interaction10amesoscale models10amesoscale processes10anumerical analysis/modeling1 aKaturji, Marwan1 aKhan, Basit1 aSprenger, Michael, A.1 aDatta, Rajasweta1 aJoy, Kurt1 aZawar-Reza, Peyman1 aHawes, Ian uhttps://journals.ametsoc.org/view/journals/apme/58/11/jamc-d-18-0336.1.xml01860nas 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-y01803nas a2200133 4500008004100000022001800041245011100059210006900170250000800239260002200247520132400269100002001593856005601613 2019 eng d a978042942970500aPlacing the past: The McMurdo Dry Valleys and the problem of geographical specificity in Antarctic history0 aPlacing the past The McMurdo Dry Valleys and the problem of geog a1st aLondonbRoutledge3 a

This chapter uses the history of the McMurdo Dry Valleys to think about the problem of geographical specificity in Antarctica. As the largest predominantly ice-free region in the Antarctic continent, the McMurdo Dry Valleys are in some ways quite different from the surrounding landscape. But despite this difference, the region has been used by scientists to make broad claims about Antarctica as a whole. While using the McMurdo Dry Valleys in this way helps to increase the relevance of the research conducted in this part of the continent, it also risks ‘flattening’ the rest of Antarctica and assuming that there are connections and similarities where none may exist. These risks of flattening the continent are arguably exacerbated by the concept of the Anthropocene, which assumes a universal human impact across the planet. Such observations call for a nuanced understanding of regions such as the McMurdo Dry Valleys which acknowledge the specificity of place, but also consider how they fit into the broader picture of Antarctic history. The paper concludes by arguing that a one-size-fits-all vision of the Anthropocene does not seem appropriate for thinking about the past, present, or future of a continent where we are only just coming to appreciate the richness and diversity of place.

1 aHowkins, Adrian uhttps://www.taylorfrancis.com/books/e/978042942970503892nas 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/s41586-019-1418-602347nas 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.1272902723nas a2200229 4500008004100000245015600041210006900197260001200266300001600278490000700294520192000301100002202221700002102243700002402264700002002288700002502308700001702333700002402350700002902374700002502403856006502428 2017 eng d00aCharacterizing hyporheic exchange processes using high-frequency electrical conductivity-discharge relationships on subhourly to interannual timescales0 aCharacterizing hyporheic exchange processes using highfrequency  c05/2017 a4124 - 41410 v533 a

Concentration-discharge (C-Q) relationships are often used to quantify source water contributions and biogeochemical processes occurring within catchments, especially during discrete hydrological events. Yet, the interpretation of C-Q hysteresis is often confounded by complexity of the critical zone, such as numerous source waters and hydrochemical nonstationarity. Consequently, researchers must often ignore important runoff pathways and geochemical sources/sinks, especially the hyporheic zone because it lacks a distinct hydrochemical signature. Such simplifications limit efforts to identify processes responsible for the transience of C-Q hysteresis over time. To address these limitations, we leverage the hydrologic simplicity and long-term, high-frequency Q and electrical conductivity (EC) data from streams in the McMurdo Dry Valleys, Antarctica. In this two end-member system, EC can serve as a proxy for the concentration of solutes derived from the hyporheic zone. We utilize a novel approach to decompose loops into subhysteretic EC-Q dynamics to identify individual mechanisms governing hysteresis across a wide range of timescales. We find that hydrologic and hydraulic processes govern EC response to diel and seasonal Q variability and that the effects of hyporheic mixing processes on C-Q transience differ in short and long streams. We also observe that variable hyporheic turnover rates govern EC-Q patterns at daily to interannual timescales. Last, subhysteretic analysis reveals a period of interannual freshening of glacial meltwater streams related to the effects of unsteady flow on hyporheic exchange. The subhysteretic analysis framework we introduce may be applied more broadly to constrain the processes controlling C-Q transience and advance understanding of catchment evolution. 

1 aSingley, Joel, G.1 aWlostowski, Adam1 aBergstrom, Anna, J.1 aSokol, Eric, R.1 aTorrens, Christa, L.1 aJaros, Chris1 aWilson, Colleen, E.1 aHendrickson, Patrick, J.1 aGooseff, Michael, N. uhttp://onlinelibrary.wiley.com/doi/10.1002/2016WR019739/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/nature2462102308nas a2200217 4500008004100000022001400041245010100055210006900156260001200225300001400237490000700251520161900258100002501877700001601902700002001918700002201938700002401960700001801984700002402002856006402026 2017 eng d a0722-406000aFreshwater diatom biogeography and the genus Luticola: an extreme case of endemism in Antarctica0 aFreshwater diatom biogeography and the genus Luticola an extreme c03/2017 a1185-11960 v403 a

Historical views have characterized Antarctica as a frozen desert with low diversity, although recent studies suggest that this may not be true for microscopic organisms. For microbes, assessing endemism in the Antarctic region has been particularly important, especially against a backdrop of debate regarding their presumed cosmopolitan nature. To contribute to this conversation, we highlight the observed endemism of the freshwater diatom genus Luti- cola in Antarctica by synthesizing the results of a modern high-resolution taxonomy from the Continental, Maritime, and sub-Antarctic regions. We report that Luticola has one of the highest endemic rates of any diatom genus in Antarctica, in terms of total number of species (taxon endemism) and percentage of the entire genus (phylogenetic endemism). Of the over 200 species of Luticola globally, nearly 20% (43) occur in the Antarctic, with 42 of these being endemic. Within regions, Maritime Antarctica has the largest number of Luticola species and endemics (28 and 23, respectively), followed by Continental Antarctica (14, 9) and sub-Antarctic islands (8, 6). Thus, 38 of the 42 endemics are found in a single region only. While the timing of Luticola diversi cation has not been established, fossil evidence suggests recent invasions and/or diversi cation over a relatively short geologic timescale. Understanding the origin and evolution of endemic diatom species in Antarctica will help us better understand microbial biogeography, as well as assess and interpret impacts of large-scale environmental change taking place at southern latitudes.

1 aKociolek, J. Patrick1 aKopalova, K1 aHamsher, S., E.1 aKohler, Tyler, J.1 aVan de Vijver, Bart1 aConvey, Peter1 aMcKnight, Diane, M. uhttps://link.springer.com/article/10.1007/s00300-017-2090-700535nas a2200145 4500008004100000245008700041210006900128260001200197300001200209490000700221100002100228700002400249700002300273856009300296 2017 eng d00aLandscape-scale soil phosphorus variability in the McMurdo Dry Valleys, Antarctica0 aLandscapescale soil phosphorus variability in the McMurdo Dry Va c06/2017 a252-2630 v291 aHeindel, Ruth, C1 aSpickard, Angela, M1 aVirginia, Ross, A. uhttps://www.cambridge.org/core/product/identifier/S0954102016000742/type/journal_article02127nas 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/10.1111/1462-2920.1372102681nas a2200133 4500008004100000245008100041210006900122260003800191490000900229520214800238100002202386700002602408856011302434 2017 eng d00aNitrate Dynamics Under Unsteady and Intermittent Flow in an Antarctic Stream0 aNitrate Dynamics Under Unsteady and Intermittent Flow in an Anta bUniversity of Colorado at Boulder0 vM.S.3 a

Low order streams are a primary vector and modulator for the transport of anthropogenically derived reactive nitrogen, especially as nitrate (NO3–). A large proportion of low orders streams experience short-term unsteady and intermittent flow conditions, and the prevalence of these dynamics is likely to increase due to climate change and human management. While such hydrologic variability is recognized as an important first-order control on the transport of NO3–, prior reliance on manual sampling has resulted in a disparity between our understanding physical and hydrochemical dynamics at short-timescales, such that a large gap exists in our understanding of how unsteady and intermittent sub-daily discharge affects instream NO3– transport patterns. To address this challenge, I used in situ sensors to collect high-frequency (i.e., 15 minute) NO3– concentration and discharge data in an ephemeral, oligotrophic glacial meltwater stream in the McMurdo Dry Valleys, Antarctica. I analyzed concentration-discharge relationships using a power-law framework to identify a flow threshold that governed NO3– transport dynamics. I observed relative chemostasis of NO3– during large magnitude diel flood pulsing events. This suggests that biological and physical processes controlling the transport and transformation of NO3–, and N more generally, are likely to exhibit spatial and temporal variability at very short timescales in response to extreme hydrologic variability. Such spatiotemporal variability in N processing dynamics has not been included in prior conceptual models of N cycling in MDV streams. As such, I propose a conceptual model in which short-term flow pulsing and cessation shift sediment redox conditions and microbial processes such that the shallow hyporheic zone temporally becomes a net source and storage zone for a spatially distributed pool of NO3–. The results of this approach will inform understanding of how highly variable hydrological conditions measured at very short timescales interacts with instream biogeochemical processes to control N transport.

1 aSingley, Joel, G.1 aHinckley, Eve-Lyn, S. uhttp://search.proquest.com/openview/88a6ce6614e2a0cfc757c8fd7a887504/1?pq-origsite=gscholar&cbl=18750&diss=y01407nas 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/abstract01022nas a2200289 4500008004100000245010700041210006900148260001200217300001400229490000700243100002800250700002200278700002500300700001900325700002000344700002700364700002500391700002600416700002300442700001700465700001900482700002000501700002100521700001800542700002100560856015100581 2016 eng d00aBiogeochemistry and microbial diversity in the marine cavity beneath the McMurdo Ice Shelf, Antarctica0 aBiogeochemistry and microbial diversity in the marine cavity ben c11/2015 a572 - 5860 v611 aVick-Majors, Trista, J.1 aAchberger, Amanda1 aSantibáñez, Pamela1 aDore, John, E.1 aHodson, Timothy1 aMichaud, Alexander, B.1 aChristner, Brent, C.1 aAi, Jill., Mikucki Ji1 aSkidmore, Mark, L.1 aPowell, Ross1 aAdkins, Peyton1 aBarbante, Carlo1 aMitchell, Andrew1 aScherer, Reed1 aPriscu, John, C. uhttp://doi.wiley.com/10.1002/lno.v61.2http://doi.wiley.com/10.1002/lno.10234http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Flno.1023400939nas 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.html00694nas a2200205 4500008004100000022001400041245012500055210006900180260001600249300001400265490000700279100002000286700001800306700002300324700001900347700002000366700001700386700002300403856006200426 2016 eng d a0831-279600aGenetic diversity among populations of Antarctic springtails (Collembola) within the Mackay Glacier ecotone 10 aGenetic diversity among populations of Antarctic springtails Col cJan-09-2016 a762 - 7700 v591 aBeet, Clare, R.1 aHogg, Ian, D.1 aCollins, Gemma, E.1 aCowan, Don, A.1 aWall, Diana, H.1 aAdams, Byron1 aWilson, John-James uhttp://www.nrcresearchpress.com/doi/10.1139/gen-2015-019402953nas a2200169 4500008004100000245010500041210006900146260001200215300001400227490000700241520241100248100001502659700002302674700002202697700002102719856004302740 2016 eng d00aGrowth dynamics of a laminated microbial mat in response to variable irradiance in an Antarctic lake0 aGrowth dynamics of a laminated microbial mat in response to vari c02/2016 a396 - 4100 v613 a
  1. Laminated microbial mats are important ecosystem components of perennially ice-covered Antarctic dry valley lakes. In order to understand better their response to changing environment, we made observations and carried out a manipulation experiment to determine their response to variations in irradiance in Lake Hoare (77°38′ S, 162°53′ E).
  2. Ice transparency was the most variable parameter that affected benthic light dose, both spatially and between years. Patterns of lamina accrual corresponded to irradiance history, with laminae that were initiated in high transmission years thicker than those from low transmission years.
  3. A shading experiment confirmed that accrual of lamina thickness, calcite precipitation and ash-free dry mass were determined by irradiance, but photosynthetic biomass and phototrophic species composition were less affected.
  4. Buried laminae decomposed only slowly over time, with potentially viable phototrophs many laminae down into the microbial mat. Decay rate increased only slightly with shading.
  5. We conclude that the microbial mats in Lake Hoare are characterised by remarkable stability, with slow accumulation rates and turnover of biomass over time. Photosynthetic biomass and species composition appeared to be stable across long time periods, with interannual variation in lamination pattern due to differential accumulation of extracellular polysaccharide and representing the visible expression of annual growth conditions.
1 aHawes, Ian1 aJungblut, Anne, D.1 aObryk, Maciek, K.1 aDoran, Peter, T. uhttp://doi.wiley.com/10.1111/fwb.1271500691nas a2200157 4500008004100000245015400041210006900195260001600264300001400280490000800294100002400302700001800326700001700344700002400361856014800385 2016 eng d00aHigh levels of intraspecific genetic divergences revealed for Antarctic springtails: evidence for small-scale isolation during Pleistocene glaciation0 aHigh levels of intraspecific genetic divergences revealed for An cJan-09-2016 a166 - 1780 v1191 aBennett, Kristi, R.1 aHogg, Ian, D.1 aAdams, Byron1 aHebert, Paul, D. N. uhttps://academic.oup.com/biolinnean/article-lookup/doi/10.1111/bij.12796https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fbij.1279600639nas 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.015903802462nas 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/S092181811530014X00761nas a2200241 4500008004100000022001400041245009900055210006900154260001200223300001400235490000700249100002300256700001500279700002200294700001800316700002100334700002100355700002400376700001900400700002700419700001800446856005500464 2016 eng d a0099-224000aMicrobial Mat Communities along an Oxygen Gradient in a Perennially Ice-Covered Antarctic Lake0 aMicrobial Mat Communities along an Oxygen Gradient in a Perennia c01/2016 a620 - 6300 v821 aJungblut, Anne, D.1 aHawes, Ian1 aMackey, Tyler, J.1 aKrusor, Megan1 aDoran, Peter, T.1 aSumner, Dawn, Y.1 aEisen, Jonathan, A.1 aHillman, Colin1 aGoroncy, Alexander, K.1 aStams, A., J. uhttp://aem.asm.org/lookup/doi/10.1128/AEM.02699-1502208nas a2200181 4500008004100000022001400041245010400055210006900159260001200228300001100240520160100251100002201852700002101874700001801895700002701913700002101940856006501961 2016 eng d a0022-143000aModeling the thickness of perennial ice covers on stratified lakes of the Taylor Valley, Antarctica0 aModeling the thickness of perennial ice covers on stratified lak c06/2016 a1 - 103 a
A 1-D ice cover model was developed to predict and constrain drivers of long-term ice thickness trends in chemically stratified lakes of Taylor Valley, Antarctica. The model is driven by surface radiative heat fluxes and heat fluxes from the underlying water column. The model successfully reproduced 16 a (between 1996 and 2012) of ice thickness changes for the west lobe of Lake Bonney (average ice thickness = 3.53 m) and Lake Fryxell (average ice thickness = 4.22 m). Long-term ice thickness trends require coupling with the thermal structure of the water column. The heat stored within the temperature maximum of lakes exceeding a liquid water column depth of 20 m can either impede or facilitate ice thickness change depending on the predominant climatic trend (cooling or warming). As such, shallow (<20 m deep water columns) perennially ice-covered lakes without deep temperature maxima are more sensitive indicators of climate change. The long-term ice thickness trends are a result of surface energy flux and heat flux from the deep temperature maximum in the water column, the latter of which results from absorbed solar radiation.

 

1 aObryk, Maciek, K.1 aDoran, Peter, T.1 aHicks, J., A.1 aMcKay, Christopher, P.1 aPriscu, John, C. uhttp://www.journals.cambridge.org/abstract_S002214301600069100627nas a2200133 4500008004100000022001300041245014500054210006900199260001200268300001100280490000700291100002000298856017500318 2016 eng d a0967340700aTaylor's Valley: What the History of Antarctica's 'Heroic Era' Can Contribute to Contemporary Ecological Research in the McMurdo Dry Valleys0 aTaylors Valley What the History of Antarcticas Heroic Era Can Co c01/2016 a3 - 280 v221 aHowkins, Adrian uhttp://openurl.ingenta.com/content/xref?genre=article&issn=0967-3407&volume=22&issue=1&spage=3http://www.ingentaconnect.com/content/whp/eh/2016/00000022/00000001/art0000303338nas a2200193 4500008004100000022001400041245010600055210006900161260001600230300001400246490000600260520270300266100002102969700002302990700002503013700002603038700002703064856005303091 2015 eng d a1752-089400aAccumulation and marine forcing of ice dynamics in the western Ross Sea during the last deglaciation0 aAccumulation and marine forcing of ice dynamics in the western R cJan-07-2016 a625 - 6280 v83 a

The grounding line of the ice sheet in the Ross Sea, Antarctica, retreated between the Last Glacial Maximum and the present. However, the timing of the retreat and the interplay of factors controlling ice stability in this region1 remain uncertain. Here we use 180 radiocarbon dates to reconstruct the chronology of moraine construction on the headlands adjacent to western McMurdo Sound. On the basis of these dates we then assess the timing of ice expansion and retreat in the Ross drainage system that is fed from both the East and West Antarctic ice sheets. We find that grounded ice in the western Ross Sea achieved its greatest thickness and extent during the last termination, between 12,800 and 18,700 years ago. Maximum ice thickness at our site coincides with a period of high accumulation as recorded by the West Antarctic Ice Sheet Divide ice core2. Recession of the ice sheet from the headland moraines began about 12,800 years ago, despite continued high accumulation and the expansion of land-based glaciers at this time. We therefore suggest that the grounding-line retreat reflects an increased marine influence as sea levels rose and the ocean warmed. We suggest that future instability in the ice sheet grounding line may occur whenever the ocean forcing is stronger than forcing from accumulation.

 
 
1 aHall, Brenda, L.1 aDenton, George, H.1 aHeath, Stephanie, L.1 aJackson, Margaret, S.1 aKoffman, Tobias, N. B. uhttp://www.nature.com/doifinder/10.1038/ngeo247804921nas a2200181 4500008004100000022001400041245008200055210006900137260001200206300001300218520434700231100002104578700001504599700002204614700002304636700002104659856005904680 2015 eng d a0091-761300aAntarctic microbial mats: A modern analog for Archean lacustrine oxygen oases0 aAntarctic microbial mats A modern analog for Archean lacustrine  c10/2015 aG36966.13 a

The evolution of oxygenic photosynthesis was the most important geochemical event in

Earth history, causing the Great Oxidation Event (GOE) ~2.4 b.y. ago. However, evidence is mixed as to whether O2 production occurred locally as much as 2.8 b.y. ago, creating O2 oases, or initiated just prior to the GOE. The biogeochemical dynamics of possible O2 oases have been poorly constrained due to the absence of modern analogs. However, cyanobacteria in microbial mats in a perennially anoxic region of Lake Fryxell, Antarctica, create a 1–2 mm O2-containing layer in the upper mat during summer, providing the first known modern analog for formation of benthic O2 oases. In Lake Fryxell, benthic cyanobacteria are present below the oxycline in the lake. Mat photosynthesis rates were slow due to low photon flux rate (1–2 μmol m-2 s-1) under thick ice cover, but photosynthetic O2 production was sufficient to sustain up to 50 μmol O2 L-1, sandwiched between anoxic overlying water and anoxic sedi- ments. We hypothesize that Archean cyanobacteria could have similarly created O2 oases in benthic mats prior to the GOE. Analogous mats may have been at least partly responsible for geological evidence of oxidative weathering prior to the GOE, and habitats such as Lake Fryxell provide natural laboratories where the impact of benthic O2 oases on biogeochemical signatures can be investigated. 

 

1 aSumner, Dawn, Y.1 aHawes, Ian1 aMackey, Tyler, J.1 aJungblut, Anne, D.1 aDoran, Peter, T. uhttp://geology.gsapubs.org/lookup/doi/10.1130/G36966.103959nas a2200205 4500008004100000022001400041245008900055210006900144260001200213300001600225490000700241520327000248100001403518700002303532700001503555700002303570700002103593700002203614856011703636 2015 eng d a0722-406000aCyanobacterial diversity in benthic mats of the McMurdo Dry Valley lakes, Antarctica0 aCyanobacterial diversity in benthic mats of the McMurdo Dry Vall c01/2015 a1097 - 11100 v383 a
Perennially ice-covered, meromictic lakes in the McMurdo Dry Valleys, Antarctica, are useful models to study the relationship between cyanobacterial and environmental variables. They have rich benthic cyanobacterial mat accumulations and stable stratification of physical and chemical conditions. Here, we evaluated cyanobacteria from benthic mats from multiple depths in three geographically separated ice-covered lakes, Lakes Vanda, Hoare and Joyce, using 16S rRNA gene clone libraries. We identified 19 ribotypes, mostly Oscillatoriales and several
Chroococcales, as well as potentially novel cyanobacterial ribotypes. The majority of ribotype diversity was shared between lakes, and only a weak relationship between ribotype community structure and environmental variables was evident. Multivariate analysis of all lake–depth combinations implied that photosynthetically active radiation, dissolved reactive phosphorus and conductivity were potentially important for shaping benthic communities in McMurdo Dry Valley lakes. Cyanobacterial-specific pigment signature analysis by high-performance liquid chromatography
showed that the cyanobacterial communities responded to light conditions similarly, irrespective of community composition. The results imply a capability within a suite of cyanobacteria to colonise, adapt and grow across broad environmental ranges and geographic space, and such adaptability may provide a high degree of community resistance and resilience to future climate-driven environmental change in Antarctic terrestrial aquatic
ecosystems.
1 aZhang, L.1 aJungblut, Anne, D.1 aHawes, Ian1 aAndersen, Dale, T.1 aSumner, Dawn, Y.1 aMackey, Tyler, J. uhttp://link.springer.com/10.1007/s00300-015-1669-0http://link.springer.com/content/pdf/10.1007/s00300-015-1669-002358nas 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/ES14-00281.102023nam a2200133 4500008004100000020002200041245004800063210004300111260002200154300000800176520161400184100002001798856007101818 2015 eng d a978-0-7456-7080-500aThe Polar Regions: An Environmental History0 aPolar Regions An Environmental History aCambridgebPolity a2483 a

The environmental histories of the Arctic and Antarctica are characterised by contrast and contradiction. These are places that have witnessed some of the worst environmental degradation in recent history. But they are also the locations of some of the most farsighted measures of environmental protection. They are places where people have sought to conquer nature through exploration and economic development, but in many ways they remain wild and untamed. They are the coldest places on Earth, yet have come to occupy an important role in the science and politics of global warming. 

Despite being located at opposite ends of the planet and being significantly different in many ways, Adrian Howkins argues that the environmental histories of the Arctic and Antarctica share much in common and have often been closely connected. This book also argues that the Polar Regions are strongly linked to the rest of the world, both through physical processes and through intellectual and political themes. As places of inherent contradiction, the Polar Regions have much to contribute to the way we think about environmental history and the environment more generally.

1 aHowkins, Adrian uhttp://www.wiley.com/WileyCDA/WileyTitle/productCd-0745670806.html04908nas a2200193 4500008004100000022001300041245008800054210006900142260001600211300001200227490000700239520413400246100002304380700002204403700002004425700001804445700002104463856023004484 2015 eng d a0883292700aReconstructing the evolution of Lake Bonney, Antarctica using dissolved noble gases0 aReconstructing the evolution of Lake Bonney Antarctica using dis cJan-07-2015 a46 - 610 v583 a

Lake Bonney (LB), located in Taylor valley, Antarctica, is a perennially ice-covered lake with two lobes, West Lake Bonney (WLB) and East Lake Bonney (ELB), which are separated by a narrow ridge. Numerous studies have attempted to reconstruct the evolution of LB because of its sensitivity to climatic variations and the lack of reliable millennial-scale continental records of climate in this region of Antarctica. However, these studies are limited by the availability of accurate lacustrine chronologies. Here, we attempt to better constrain the chronology of LB and thus, the evolution of past regional climate by estimating water residence times based on He, Ne and Ar concentrations and isotopic ratios in both WLB and ELB.

3He and 4He excesses up to two and three orders of magnitude and 35–150 times the atmospheric values are observed for WLB and ELB samples, respectively. In comparison, while measured 40Ar/36Ar ratios are atmospheric (∼295.5) in ELB, WLB samples display 40Ar/36Ar ratios of up to ∼315 reflecting addition of radiogenic 40Ar. Both4He and 40Ar excesses clearly identify the addition of subglacial discharge (SGD) from underneath Taylor Glacier into WLB at depths of 25 m and 35 m. He isotopic ratios suggest that He excesses are predominantly crustal (>93%) in origin with small mantle contributions (<7%). These crustal 4He and 40Ar excesses are used together with basement rock production rates of these isotopes to derive first-order approximations of water residence times for both lobes. Numerous factors capable of affecting water residence times are evaluated and corrected 4He and 40Ar water ages are used to place further constrains into the reconstruction of both WLB and ELB history. Combined 4He and 40Ar ages in WLB suggest maximum water residence times of ∼250 kyrs BP. These results support the presence of remnant water from proglacial lakes that existed during Marine Isotope Stage 7 (160–240 kyrs) in WLB, in agreement with previous studies. In comparison, 4He ages in ELB are much younger (<27 kyrs BP) and display a complex evolutionary history that is very different from WLB. 4He ages also suggest that the ELB ice cover formed significantly earlier (∼1.5 kyrs BP) than previously reported. The timing of these hydrologic changes in ELB appears to correspond to regional and global climatic events that are recorded in both the Taylor Dome ice-core record as well as in other Dry Valley Lakes.

1 aWarrier, Rohit, B.1 aCastro, Clara, M.1 aHall, Chris, M.1 aKenig, Fabien1 aDoran, Peter, T. uhttp://linkinghub.elsevier.com/retrieve/pii/S088329271500044Xhttp://api.elsevier.com/content/article/PII:S088329271500044X?httpAccept=text/xmlhttp://api.elsevier.com/content/article/PII:S088329271500044X?httpAccept=text/plain04591nas 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_S095410201400067402038nas a2200181 4500008004100000022001400041245011000055210006900165260001200234300000900246490001400255520146300269100001801732700001501750700002201765700002101787856004801808 2015 eng d a1365-207900aSediment transport dynamics on an ice-covered lake: The “floating” boulders of Lake Hoare, Antarctica0 aSediment transport dynamics on an icecovered lake The floating b c04/2015 a1-120 vfirstview3 a

Between 1995 and 2011 a global positioning system survey of 13 boulders and three ablation stakes (long stakes frozen in the ice) on the frozen surface of Lake Hoare was undertaken. Data interpretation illustrates complexities of post-depositional transport dynamics of boulders. Earlier studies on comparable datasets have suggested linear ‘conveyor’ type transport mechanisms for lake surface boulders. Yet explanations for non-linear boulder displacements or ‘walks’ and the mechanisms responsible for movements are inadequate. Two modes of boulder specific movement were observed. First, localized changes in the ice surface promote individual boulder movement (rolling). Second, ice rafting, which indicates the displacement of ‘plates’ of lake ice on which the boulder is located. Ablation stakes used as fixed survey control points support the hypothesis that ice cover moves as discrete plates rather than as a single homogenous mass. Factors that create the conditions to generate either of the two modes of movement may be related to location specific energy budgets. A relationship between average orientations and prevailing wind direction was also observed. The investigation describes the local-scale behaviour of surveyed boulders, and offers methodologies and interpretive frameworks for additional studies of modern and ancient sediment transportation dynamics in Antarctic lacustrine environments.

1 aAllen, P., P.1 aHewitt, R.1 aObryk, Maciek, K.1 aDoran, Peter, T. uhttp://dx.doi.org/10.1017/S095410201400055800545nas a2200133 4500008004100000245014400041210006900185260001200254300001200266490000700278100001800285700002000303856008800323 2015 eng d00aTipping the Iceberg: A Collaborative Approach to Redesigning the Undergraduate Research Assignment in an Antarctic History Capstone Seminar0 aTipping the Iceberg A Collaborative Approach to Redesigning the  c03/2015 a339-3700 v481 aHicks, Alison1 aHowkins, Adrian uhttp://scholar.colorado.edu/cgi/viewcontent.cgi?article=1034&context=libr_facpapers02755nas a2200169 4500008004100000020002200041245005500063210005300118260005100171300001200222520220300234100001902437700001802456700002202474700002002496856006902516 2014 eng d a978-3-642-45212-300aAntarctic Terrestrial Microbiology : Invertebrates0 aAntarctic Terrestrial Microbiology Invertebrates aBerlin, HeidelbergbSpringer Berlin Heidelberg a55 - 783 a

Terrestrial invertebrates are the largest permanent residents for much of the Antarctic continent with body lengths < 2 mm for most. The fauna consists of the arthropod taxa Collembola (springtails) and Acari (mites) as well as the microinvertebrates Nematoda, Tardigrada and Rotifera. Diversity in continental Antarctica is lower compared with warmer regions such as the Antarctic Peninsula and the subantarctic islands and several taxa such as the arthropods have considerably restricted distributions. The highest diversity of invertebrates is found along the Transantarctic Mountains of the Ross Sea Region and taxa are likely to be relicts from a warmer past that have survived in glacial refugia. Dispersal among the extremely fragmented Antarctic landscape is likely to be limited to transport via fresh- or salt-waters, particularly for the arthropod taxa, although long-distance wind dispersal is also possible for the microinvertebrates. Invertebrates possess several adaptations to low moisture levels and extreme cold temperatures in Antarctica. For example, nematodes and tardigrades avoid extreme dry and cold temperatures by entering a desiccation-resistant anhydrobiotic state. In contrast, arthropods do not have such a resistant state and freezing is lethal. Adaptations for the arthropod taxa include freeze avoidance and the production of intracellular, antifreeze proteins. Climate changes in Antarctica are likely to pose significant challenges for the invertebrate fauna. Changes in temperature, soil moisture and associated shifts in taxon distributions as well as the potential for non-indigenous species introductions are all likely to have considerable impacts on the Antarctic fauna. From a conservation perspective, there is a pressing need for terrestrial observation networks to record the present state of Antarctic terrestrial ecosystems as well as to monitor impending changes. Biosecurity measures which minimize species introductions or transfers of organisms within Antarctica will be essential.

1 aCowan, Don, A.1 aHogg, Ian, D.1 aStevens, Mark, I.1 aWall, Diana, H. uhttp://link.springer.com/content/pdf/10.1007/978-3-642-45213-0_402341nas a2200157 4500008004100000245017500041210006900216260001200285300001200297490000700309520168800316100001502004700001402019700002102033856012902054 2014 eng d00aEstimating photosynthetic activity in microbial mats in an ice-covered Antarctic lake using automated oxygen microelectode profiling and variable chlorophyll fluorescence0 aEstimating photosynthetic activity in microbial mats in an iceco c08/2014 a674-6880 v593 a An automated oxygen microprofiler measured a positive flux of oxygen from microbial mats in ice-covered Lake Hoare, Antarctica, from noon, at a photon flux of 20 µmol m−2 s−1, through to midnight (< 2 µmol photons m−2 s−1). Daily average oxygen flux was 200 µmol m−2 h−1; and, whereas it was maximal at noon, when a 10 mm broad concentration peak was observed 5 mm below the mat surface, flux correlated only weakly with irradiance. In contrast, relative electron transfer rate, estimated from variable chlorophyll fluorescence, suggested a linear relationship between photosystem activity and irradiance. This contradiction arose because of the conjunction of photosynthetic production of oxygen deep into these transparent, gelatinous mats (diel oxygen change was observed to 17 mm depth) and oxygen diffusion rates too slow to allow equilibration of oxygen concentration profiles with instantaneous production and consumption of oxygen. To confirm this, we developed a mathematical simulation of oxygen dynamics that included diffusion, photosynthesis, and respiration. The simulation further indicated that (1) net oxygen evolution is light limited is and confined to the upper few millimeters of the mat, (2) below 5–7 mm, respiration balanced photosynthesis, (3) below 17 mm, respiration and photosynthesis approached zero, even though organic carbon and dissolved oxygen were present, and (4) photosynthesis deep into the mat was dependent on high light transmission through the gelatinous matrix. These conclusions are consistent with current understanding of mat growth dynamics and point to approaches for long-term analysis of microbial mat productivity.1 aHawes, Ian1 aGiles, H.1 aDoran, Peter, T. uhttps://mcm.lternet.edu/content/estimating-photosynthetic-activity-microbial-mats-ice-covered-antarctic-lake-using-automated01873nas a2200241 4500008004100000022001400041245005200055210005100107260001200158300001400170490000700184520122300191100001401414700001501428700002001443700002101463700001501484700001401499700001601513700002001529700001501549856006701564 2014 eng d a1084-545300aForum: Climate Change and Environmental History0 aForum Climate Change and Environmental History c04/2014 a281 - 3640 v193 a

This Forum explores global climate change, one of this century's most prominent environmental issues. Authors answer two critical questions: (1) How does the study of climate history enrich the field of environmental history more broadly? (2) How can environmental historians contribute to present-day understandings of and responses to global climate change? This introductory essay (and the Forum more generally) contribute to both environmental history research and climate change discussions by grappling with several key issues including the agency of nonhuman nature and environmental determinism, environmental governance, climate as a cultural construction, the history of environmental ideas and discourse, environmental narratives, the commodification of nature, and the politicization of the natural and life sciences. This essay also shows how the study of climate history provides methodological and practical tools for environmental historians. It analyzes the role of interdisciplinary sources and archives, scale, the place of science in environmental history scholarship, and the relevance of environmental histories for present-day policymaking and public discussions about climate change.

1 aCarey, M.1 aGarone, P.1 aHowkins, Adrian1 aEndfield, G., H.1 aCulver, L.1 aWhite, S.1 aJohnson, S.1 aFleming, J., R.1 aGarone, P. uhttp://envhis.oxfordjournals.org/cgi/doi/10.1093/envhis/emu00401695nas 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_S095410201300097701831nas 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/abstract03560nas 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/10.1890/12-2216.102923nas a2200229 4500008004100000245012800041210006900169260001200238490000600250520215100256100001602407700002602423700002002449700002402469700002202493700001802515700002402533700001702557700002302574700001902597856007702616 2014 eng d00aSpring thaw ionic pulses boost nutrient availability and microbial growth in entombed Antarctic Dry Valley cryoconite holes0 aSpring thaw ionic pulses boost nutrient availability and microbi c12/20140 v53 a

The seasonal melting of ice entombed cryoconite holes on McMurdo Dry Valley glaciers provides oases for life in the harsh environmental conditions of the polar desert where surface air temperatures only occasionally exceed 0°C during the Austral summer. Here we follow temporal changes in cryoconite hole biogeochemistry on Canada Glacier from fully frozen conditions through the initial stages of spring thaw toward fully melted holes. The cryoconite holes had a mean isolation age from the glacial drainage system of 3.4 years, with an increasing mass of aqueous nutrients (dissolved organic carbon, total nitrogen, total phosphorus) with longer isolation age. During the initial melt there was a mean nine times enrichment in dissolved chloride relative to mean concentrations of the initial frozen holes indicative of an ionic pulse, with similar mean nine times enrichments in nitrite, ammonium, and dissolved organic matter. Nitrate was enriched twelve times and dissolved organic nitrogen six times, suggesting net nitrification, while lower enrichments for dissolved organic phosphorus and phosphate were consistent with net microbial phosphorus uptake. Rates of bacterial production were significantly elevated during the ionic pulse, likely due to the increased nutrient availability. There was no concomitant increase in photosynthesis rates, with a net depletion of dissolved inorganic carbon suggesting inorganic carbon limitation. Potential nitrogen fixation was detected in fully melted holes where it could be an important source of nitrogen to support microbial growth, but not during the ionic pulse where nitrogen availability was higher. This study demonstrates that ionic pulses significantly alter the timing and magnitude of microbial activity within entombed cryoconite holes, and adds credence to hypotheses that ionic enrichments during freeze-thaw can elevate rates of microbial growth and activity in other icy habitats, such as ice veins and subglacial regelation zones

1 aTelling, J.1 aAnesio, Alexandre, M.1 aTranter, Martyn1 aFountain, Andrew, G1 aNylen, Thomas, H.1 aHawkings, Jon1 aSingh, Virendra, B.1 aKaur, Preeti1 aMusilova, Michaela1 aWadham, J., L. uhttp://journal.frontiersin.org/article/10.3389/fmicb.2014.00694/abstract00634nas 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-2013073000663nas 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-saline00577nas 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-704-2013020100643nas 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-mountains04191nas 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.122282100684nas 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/full01724nam a2200385 4500008004100000020002200041245011900063210006900182260005100251300001400302490000900316520052100325100002500846700002200871700001900893700002500912700002700937700002000964700002300984700002101007700002101028700001801049700001901067700001901086700001901105700002201124700001401146700002001160700002101180700002101201700002001222700001901242700001901261856005801280 2012 eng d a978-3-642-33179-400aPoisson Reconstruction of Extreme Submersed Environments: The ENDURANCE Exploration of an Under-Ice Antarctic Lake0 aPoisson Reconstruction of Extreme Submersed Environments The END aBerlin, HeidelbergbSpringer Berlin Heidelberg a394 - 4030 v74313 a

We evaluate the use of Poisson reconstruction to generate a 3D bathymetric model of West Lake Bonney, Antarctica. The source sonar dataset has been collected by the ENDURANCE autonomous ve- hicle in the course of two Antarctic summer missions. The reconstruction workflow involved processing 200 million datapoints to generate a high resolution model of the lake bottom, Narrows region and underwater glacier face. A novel and flexible toolset has been developed to automate the processing of the Bonney data.

1 aFebretti, Alessandro1 aRichmond, Kristof1 aGulati, Shilpa1 aFlesher, Christopher1 aHogan, Bartholomew, P.1 aJohnson, Andrew1 aStone, William, C.1 aPriscu, John, C.1 aDoran, Peter, T.1 aBebis, George1 aBoyle, Richard1 aParvin, Bahram1 aKoracin, Darko1 aFowlkes, Charless1 aWang, Sen1 aChoi, Min-Hyung1 aMantler, Stephan1 aSchulze, Jürgen1 aAcevedo, Daniel1 aMueller, Klaus1 aPapka, Michael uhttp://www.springerlink.com/content/hg97w43588229087/02772nas a2200169 4500008004100000245009200041210006900133260001200202490000800214520222300222100002302445700001502468700001502483700002402498700001502522856006502537 2012 eng d00aSeismic multiplet response triggered by melt at Blood Falls, Taylor Glacier, Antarctica0 aSeismic multiplet response triggered by melt at Blood Falls Tayl c07/20120 v1173 a

Meltwater input often triggers a seismic response from glaciers and ice sheets. It is difficult, however, to measure melt production on glaciers directly, while subglacial water storage is not directly observable. Therefore, we document temporal changes in seismicity from a dry-based polar glacier (Taylor Glacier, Antarctica) during a melt season using a synthesis of seismic observation and melt modeling. We record icequakes using a dense six-receiver network of three-component geophones and compare this with melt input generated from a calibrated surface energy balance model. In the absence of modeled surface melt, we find that seismicity is well-described by a diurnal signal composed of microseismic events in lake and glacial ice. During melt events, the diurnal signal is suppressed and seismicity is instead characterized by large glacial icequakes. We perform network-based correlation and clustering analyses of seismic record sections and determine that 18% of melt-season icequakes are repetitive (multiplets). The epicentral locations for these multiplets suggest that they are triggered by meltwater produced near a brine seep known as Blood Falls. Our observations of the correspondingp-wave first motions are consistent with volumetric source mechanisms. We suggest that surface melt enables a persistent pathway through this cold ice to an englacial fracture system that is responsible for brine release episodes from the Blood Falls seep. The scalar moments for these events suggest that the volumetric increase at the source region can be explained by melt input.

1 aCarmichael, J., D.1 aPettit, E.1 aHoffman, M1 aFountain, Andrew, G1 aHallet, B. uhttp://onlinelibrary.wiley.com/doi/10.1029/2011JF002221/full00474nas 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.html00626nas a2200181 4500008004100000245012300041210006900164260001100233300001200244490000700256100001600263700002000279700001200299700001700311700002200328700002300350856007100373 2012 eng d00aThawing permafrost alters nematode populations and soil habitat characteristics in an Antarctic polar desert ecosystem0 aThawing permafrost alters nematode populations and soil habitat  c3/2012 a75 - 810 v551 aSmith, T.E.1 aWall, Diana, H.1 aHogg, I1 aAdams, Byron1 aNielsen, Uffe, N.1 aVirginia, Ross, A. uhttp://www.sciencedirect.com/science/article/pii/S003140561100115600443nas a2200145 4500008004100000022001400041245005700055210005700112260001200169300001600181490000700197100001800204700002000222856005500242 2011 eng d a0722-406000aGlobal change and Antarctic terrestrial biodiversity0 aGlobal change and Antarctic terrestrial biodiversity c11/2011 a1625 - 16270 v341 aHogg, Ian, D.1 aWall, Diana, H. uhttp://link.springer.com/10.1007/s00300-011-1108-900651nas 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_S095410201100031900324nas a2200121 4500008004100000245003000041210002900071250001400100260001400114490000900128100002000137856004500157 2011 eng d00aMCM IV: Getting Connected0 aMCM IV Getting Connected aFall 2011 bLTER News0 v20131 aHowkins, Adrian uhttp://news.lternet.edu/Article2316.html00668nas 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-y00519nas a2200121 4500008004100000245009200041210006900133260004900202300000800251490001000259100001500269856011300284 2011 eng d00aSpatial and Temporal Variability of Glacier Melt in the McMurdo Dry Valleys, Antarctica0 aSpatial and Temporal Variability of Glacier Melt in the McMurdo  aPortlandbPortland State Universityc01/2011 a2960 vPh.D.1 aHoffman, M uhttps://mcm.lternet.edu/content/spatial-and-temporal-variability-glacier-melt-mcmurdo-dry-valleys-antarctica00618nas a2200169 4500008004100000245011400041210006900155260001200224300001800236490000800254100002100262700002300283700002400306700002100330700002600351856007100377 2010 eng d00aAntarctic lakes suggest millennial reorganizations of Southern Hemisphere atmospheric and oceanic circulation0 aAntarctic lakes suggest millennial reorganizations of Southern H c12/2010 a21355 - 213590 v1071 aHall, Brenda, L.1 aDenton, George, H.1 aFountain, Andrew, G1 aHendy, Chris, H.1 aHenderson, Gideon, M. uhttp://www.pnas.org/content/107/50/21355.full.pdf#page=1&view=FitH00620nas 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-matters00861nas a2200253 4500008004100000245013000041210006900171260001200240300001400252490000800266100001300274700002600287700001500313700001400328700002200342700001500364700001500379700001500394700001400409700001600423700002100439700002100460856012600481 2010 eng d00aDesign and deployment of a four-degrees-of-freedom hovering autonomous underwater vehicle for sub-ice exploration and mapping0 aDesign and deployment of a fourdegreesoffreedom hovering autonom c11/2010 a341 - 3610 v2241 aStone, W1 aHogan, Bartholomew, P1 aFlesher, C1 aGulati, S1 aRichmond, Kristof1 aMurarka, A1 aKuhlman, G1 aIdharan, M1 aSiegel, V1 aPrice, R, M1 aDoran, Peter, T.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/design-and-deployment-four-degrees-freedom-hovering-autonomous-underwater-vehicle-sub-ice00711nas a2200181 4500008004100000020001800041245009200059210006900151250000600220260003100226100002500257700002400282700001500306700002400321700001900345700002100364856014400385 2010 eng d a978052150996100aDiatoms as indicators of environmental change in Antarctic and subantarctic freshwaters0 aDiatoms as indicators of environmental change in Antarctic and s a2 bCambridge University Press1 aSpaulding, Sarah, A.1 aVan de Vijver, Bart1 aHodgson, D1 aMcKnight, Diane, M.1 aVerleyen, Elie1 aStanish, Lee, F. uhttp://www.cambridge.org/us/academic/subjects/life-sciences/plant-science/diatoms-applications-environmental-and-earth-sciences-2nd-edition00571nas a2200145 4500008004100000245009100041210006900132260001500201300001200216100001700228700002400245700002100269700002400290856011100314 2010 eng d00aA dynamic physical model for soil temperature and water in Taylor Valley, Antarctica.0 adynamic physical model for soil temperature and water in Taylor  c05/13/2010 a419-4341 aHunt, H., W.1 aFountain, Andrew, G1 aDoran, Peter, T.1 aBasagic, Hassan, J. uhttps://mcm.lternet.edu/content/dynamic-physical-model-soil-temperature-and-water-taylor-valley-antarctica00672nas a2200157 4500008004100000245016900041210006900210260001200279300001400291490000700305100002700312700001200339700002400351700001700375856012200392 2010 eng d00aLatitudinal distribution and mitochondrial DNA (COI) variability of Stereotydeus spp. (Acari: Prostigmata) in Victoria Land and the central Transantarctic Mountains0 aLatitudinal distribution and mitochondrial DNA COI variability o c12/2010 a749 - 7560 v221 aDemetras, Nicholas, J.1 aHogg, I1 aBanks, Jonathan, C.1 aAdams, Byron uhttps://mcm.lternet.edu/content/latitudinal-distribution-and-mitochondrial-dna-coi-variability-stereotydeus-spp-acari00662nas a2200181 4500008004100000245013300041210006900174260001200243300001400255490000800269100002400277700002200301700002000323700002100343700001800364700002700382856007100409 2010 eng d00aNew insights into the origin and evolution of Lake Vida, McMurdo Dry Valleys, Antarctica — A noble gas study in ice and brines0 aNew insights into the origin and evolution of Lake Vida McMurdo  c01/2010 a112 - 1220 v2891 aMalone, Jessica, L.1 aCastro, Clara, M.1 aHall, Chris, M.1 aDoran, Peter, T.1 aKenig, Fabien1 aMcKay, Christopher, P. uhttp://www.sciencedirect.com/science/article/pii/S0012821X0900633500627nas 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=CBO9780511712258A01300839nas a2200217 4500008004100000020002200041245013600063210007100199260003300270300001400303100001400317700002200331700001500353700002600368700001500394700002200409700002100431700001300452700002100465856013500486 2010 eng d a978-1-4244-5038-100aToward autonomous scientific exploration of ice-covered lakes—Field experiments with the ENDURANCE AUV in an Antarctic Dry Valley0 aToward autonomous scientific exploration of icecovered lakes—Fie aAnchorage, AKbIEEEc05/2010 a308 - 3151 aGulati, S1 aRichmond, Kristof1 aFlesher, C1 aHogan, Bartholomew, P1 aMurarka, A1 aKuhlmann, Gregory1 aSridharan, Mohan1 aStone, W1 aDoran, Peter, T. uhttps://mcm.lternet.edu/content/toward-autonomous-scientific-exploration-ice-covered-lakes%E2%80%94field-experiments-endurance-auv00918nas 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-sciences00683nas a2200169 4500008004100000245011900041210006900160300001400229490000700243100001700250700002500267700002200292700002200314700003300336700001600369856012800385 2009 eng d00aHydrologic characteristics of lake- and stream-side riparian wetted margins in the McMurdo Dry Valleys, Antarctica0 aHydrologic characteristics of lake and streamside riparian wette a1255-12670 v231 aNorthcott, M1 aGooseff, Michael, N.1 aBarrett, John, E.1 aZeglin, Lydia, H.1 aTakacs-Vesbach, Cristina, D.1 aHumphrey, J uhttps://mcm.lternet.edu/content/hydrologic-characteristics-lake-and-stream-side-riparian-wetted-margins-mcmurdo-dry-valleys00718nas 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-services00835nas 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-system02787nas 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/full00481nas 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-antarctica00626nas a2200181 4500008004100000245008300041210006900124300001400193490000700207100002000214700001600234700001400250700001100264700002200275700002000297700001900317856010800336 2008 eng d00aMicrobial community composition in soils of Northern Victoria Land, Antarctica0 aMicrobial community composition in soils of Northern Victoria La a1713-17240 v101 aNiederberger, T1 aMcDonald, i1 aHacker, A1 aSoo, R1 aBarrett, John, E.1 aWall, Diana, H.1 aCary, Craig, S uhttps://mcm.lternet.edu/content/microbial-community-composition-soils-northern-victoria-land-antarctica00685nas a2200205 4500008004100000245010300041210006900144260000900213490000700222100002300229700002300252700002900275700001500304700002300319700002100342700001500363700001500378700002500393856006100418 2008 eng d00aReply to comment by K. Gajewski on “Abrupt environmental change in Canada's northernmost lake”0 aReply to comment by K Gajewski on Abrupt environmental change in c20080 v351 aAntoniades, Dermot1 aCrawley, Catherine1 aDouglas, Marianne, S. V.1 aPienitz, R1 aAndersen, Dale, T.1 aDoran, Peter, T.1 aHawes, Ian1 aPollard, W1 aVincent, Warwick, F. uhttp://www.agu.org/pubs/crossref/2008/2007GL032889.shtml00949nas 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-scale00503nas 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-antarctica00701nas a2200193 4500008004100000245009100041210006900132300001200201490000600213100002500219700002200244700002700266700001500293700002200308700002200330700001200352700003300364856011000397 2007 eng d00aControls on the spatial dimensions of wetted hydrologic margins of two antarctic lakes0 aControls on the spatial dimensions of wetted hydrologic margins  a841-8480 v61 aGooseff, Michael, N.1 aBarrett, John, E.1 aNorthcott, Melissa, L.1 aBate, Brad1 aHill, Kenneth, R.1 aZeglin, Lydia, H.1 aBobb, M1 aTakacs-Vesbach, Cristina, D. uhttps://mcm.lternet.edu/content/controls-spatial-dimensions-wetted-hydrologic-margins-two-antarctic-lakes00539nas a2200145 4500008004100000245008300041210006900124300001200193490000700205100001200212700002000224700002000244700002300264856010600287 2007 eng d00aA mathematical model for variation in water-retention curves among sandy soils0 amathematical model for variation in waterretention curves among  a427-4360 v191 aHunt, H1 aTreonis, Amy, M1 aWall, Diana, H.1 aVirginia, Ross, A. uhttps://mcm.lternet.edu/content/mathematical-model-variation-water-retention-curves-among-sandy-soils00599nas 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.short00625nas a2200169 4500008004100000245010600041210006900147300001200216490000700228100001700235700002000252700001300272700001500285700001500300700001200315856012800327 2007 eng d00aThe southernmost worm, Scottnema lindsayae (Nematoda): diversity, dispersal and ecological stability.0 asouthernmost worm Scottnema lindsayae Nematoda diversity dispers a809-8150 v301 aAdams, Byron1 aWall, Diana, H.1 aGozel, U1 aDillman, A1 aChaston, J1 aHogg, I uhttps://mcm.lternet.edu/content/southernmost-worm-scottnema-lindsayae-nematoda-diversity-dispersal-and-ecological-stability02534nas a2200193 4500008004100000245009700041210006900138260001200207300001200219490000700231520185500238653001102093100002902104700002102133700001402154700002502168700002402193856012302217 2006 eng d00aAdaptation and acclimation of photosynthetic microorganisms to permanently cold environments0 aAdaptation and acclimation of photosynthetic microorganisms to p c03/2006 a222-2520 v703 a

Persistently cold environments constitute one of our world's largest ecosystems, and microorganisms dominate the biomass and metabolic activity in these extreme environments. The stress of low temperatures on life is exacerbated in organisms that rely on photoautrophic production of organic carbon and energy sources. Phototrophic organisms must coordinate temperature-independent reactions of light absorption and photochemistry with temperature-dependent processes of electron transport and utilization of energy sources through growth and metabolism. Despite this conundrum, phototrophic microorganisms thrive in all cold ecosystems described and (together with chemoautrophs) provide the base of autotrophic production in low-temperature food webs. Psychrophilic (organisms with a requirement for low growth temperatures) and psychrotolerant (organisms tolerant of low growth temperatures) photoautotrophs rely on low-temperature acclimative and adaptive strategies that have been described for other low-temperature-adapted heterotrophic organisms, such as cold-active proteins and maintenance of membrane fluidity. In addition, photoautrophic organisms possess other strategies to balance the absorption of light and the transduction of light energy to stored chemical energy products (NADPH and ATP) with downstream consumption of photosynthetically derived energy products at low temperatures. Lastly, differential adaptive and acclimative mechanisms exist in phototrophic microorganisms residing in low-temperature environments that are exposed to constant low-light environments versus high-light- and high-UV-exposed phototrophic assemblages.

10aBiggie1 aMorgan-Kiss, Rachael, M.1 aPriscu, John, C.1 aPocock, T1 aGudynaite-Savitch, L1 aHuner, Norman, P.A. uhttps://mcm.lternet.edu/content/adaptation-and-acclimation-photosynthetic-microorganisms-permanently-cold-environments00754nas 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-pit01738nas a2200229 4500008004100000245008300041210006900124260001200193300001100205490000700216520101800223653001101241100002501252700001201277700002401289700001101313700001301324700002501337700002101362700001601383856010901399 2006 eng d00aAntarctic Climate Cooling and Response of Diatoms in Glacial Meltwater Streams0 aAntarctic Climate Cooling and Response of Diatoms in Glacial Mel c04/2006 aL074060 v333 a

To understand biotic responses to an Antarctic cooling trend, we analyzed diatom samples from glacial meltwater streams in the McMurdo Dry Valleys, the largest ice-free area in Antarctica. Diatoms are abundant in these streams, and 24 of 40 species have only been found in the Antarctic. The percentage of these Antarctic diatom species increased with decreasing annual stream flow and increasing harshness of the stream habitat. The species diversity of assemblages reached a maximum when the Antarctic species accounted for 40–60% of relative diatom abundance. Decreased solar radiation and air-temperatures reduce annual stream flow, raising the dominance of these Antarctic species to levels above 60%. Thus, cooling favors the Antarctic species, and lowers diatom species diversity in this region.

10aBiggie1 aEsposito, Rhea, M.M.1 aHorn, S1 aMcKnight, Diane, M.1 aCox, M1 aGrant, M1 aSpaulding, Sarah, A.1 aDoran, Peter, T.1 aCozzetto, K uhttps://mcm.lternet.edu/content/antarctic-climate-cooling-and-response-diatoms-glacial-meltwater-streams00563nas 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-change00665nas a2200217 4500008004100000245008000041210006900121300001400190490000700204100001200211700002000223700001900243700001400262700001500276700001600291700001700307700001600324700002100340700001500361856007100376 2006 eng d00aBiotic interactions in Antarctic terrestrial ecosystems: Are they a factor?0 aBiotic interactions in Antarctic terrestrial ecosystems Are they a3035-30400 v381 aHogg, I1 aWall, Diana, H.1 aCary, Craig, S1 aConvey, K1 aNewsham, K1 aODonnell, G1 aAdams, Byron1 aAislabie, J1 aFrati, Francesco1 aStevens, M uhttp://www.sciencedirect.com/science/article/pii/S003807170600217300757nas a2200181 4500008004100000245010900041210006900150300001200219490000700231100002200238700002300260700002000283700001900303700001700322700001400339700001600353856020600369 2006 eng d00aCo-variation in soil biodiversity and biogeochemistry in Northern and Southern Victoria Land, Antarctica0 aCovariation in soil biodiversity and biogeochemistry in Northern a535-5480 v181 aBarrett, John, E.1 aVirginia, Ross, A.1 aWall, Diana, H.1 aCary, Craig, S1 aAdams, Byron1 aHacker, A1 aAislabie, J uhttps://www.cambridge.org/core/journals/antarctic-science/article/covariation-in-soil-biodiversity-and-biogeochemistry-in-northern-and-southern-victoria-land-antarctica/C3514C28DB75F3A19DB5F266D4B1B56E00891nas a2200325 4500008004100000245005400041210005400095300001400149490000700163100001700170700001500187700001800202700001200220700002100232700001200253700001500265700001700280700001500297700001500312700001500327700002600342700001800368700002000386700001600406700001600422700001600438700001900454700001600473856007600489 2006 eng d00aDiversity and distribution of Victoria Land biota0 aDiversity and distribution of Victoria Land biota a3003-30180 v381 aAdams, Byron1 aConnell, L1 aConvey, Peter1 aFell, J1 aFrati, Francesco1 aHogg, I1 aNewsham, K1 aO'Donnell, A1 aRussell, N1 aSeppelt, R1 aStevens, M1 aBardgett, Richard, D.1 aAyres, Edward1 aWall, Diana, H.1 aAislabie, J1 aBamforth, S1 aBargagli, R1 aCary, Craig, S1 aCavacini, P uhttps://www.sciencedirect.com/science/article/abs/pii/S003807170600221500600nas a2200145 4500008004100000245011900041210006900160300001200229490000700241100001500248700002400263700001500287700002700302856012500329 2006 eng d00aEnvironmental factors associated with deep chlorophyll maxima in dry valley lakes, South Victoria Land, Antarctica0 aEnvironmental factors associated with deep chlorophyll maxima in a179-1890 v381 aBurnett, L1 aMoorhead, Daryl, L.1 aHawes, Ian1 aHoward-Williams, Clive uhttps://mcm.lternet.edu/content/environmental-factors-associated-deep-chlorophyll-maxima-dry-valley-lakes-south-victoria00592nas 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-project00563nas a2200145 4500008004100000245009200041210006900133300001400202490000700216100002000223700001700243700002200260700002000282856011500302 2006 eng d00aA synthesis of soil biodiversity and ecosystem functioning in Victoria Land, Antarctica0 asynthesis of soil biodiversity and ecosystem functioning in Vict a3001-30020 v381 aWall, Diana, H.1 aAdams, Byron1 aBarrett, John, E.1 aHopkins, D., W. uhttps://mcm.lternet.edu/content/synthesis-soil-biodiversity-and-ecosystem-functioning-victoria-land-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-antarctica00559nas a2200157 4500008004100000245008000041210006900121490000700190100001300197700001400210700001500224700001500239700002100254700001700275856010900292 2005 eng d00aBiogeological Raman spectroscopic studies of Antarctic lacustrine sediments0 aBiogeological Raman spectroscopic studies of Antarctic lacustrin0 v611 aMoody, C1 aVillar, S1 aEdwards, H1 aHodgson, D1 aDoran, Peter, T.1 aBishop, J.L. uhttps://mcm.lternet.edu/content/biogeological-raman-spectroscopic-studies-antarctic-lacustrine-sediments00509nas a2200121 4500008004100000245009600041210006900137490000700206100002400213700001700237700001500254856011800269 2005 eng d00aContributions of Benthic Microbial Mats to Net Primary Production in Lake Hoare, Antarctica0 aContributions of Benthic Microbial Mats to Net Primary Productio0 v171 aMoorhead, Daryl, L.1 aSchmeling, S1 aHawes, Ian uhttps://mcm.lternet.edu/content/contributions-benthic-microbial-mats-net-primary-production-lake-hoare-antarctica00612nas a2200169 4500008004100000245007600041210006900117260003100186300000900217100002000226700001500246700001700261700002600278700001800304700002000322856010000342 2005 eng d00aDeveloping new perspectives from advances in soil biodiversity research0 aDeveloping new perspectives from advances in soil biodiversity r bCambridge University Press a3-301 aWall, Diana, H.1 aFritter, A1 aPaul, E., A.1 aBardgett, Richard, D.1 aUsher, M., B.1 aHopkins, D., W. uhttps://mcm.lternet.edu/content/developing-new-perspectives-advances-soil-biodiversity-research00662nas a2200193 4500008004100000245008500041210006900126260004000195300001200235100002700247700002300274700001500297700001600312700002100328700002700349700002100376700002000397856005100417 2005 eng d00aPolar lakes, streams, and springs as analogs for the hydrological cycle on Mars.0 aPolar lakes streams and springs as analogs for the hydrological  aBerlin, HeidelbergbSpringer Verlag a219-2331 aMcKay, Christopher, P.1 aAndersen, Dale, T.1 aPollard, W1 aHeldmann, J1 aDoran, Peter, T.1 aFritsen, Christian, H.1 aPriscu, John, C.1 aTokano, Tetsuya u/reports/lakes/McKayEtAl2005StreamsSprings.pdf00875nas a2200361 4500008004100000245001800041210001800059260001700077300001200094100001900106700001500125700001500140700002300155700001300178700001300191700001900204700001500223700001400238700002000252700001500272700001400287700001700301700001800318700001900336700001400355700002200369700001400391700001500405700001500420700001600435700001200451856005000463 2005 eng d00aPolar Systems0 aPolar Systems bIsland Press a717-7431 aChapin, F., S.1 aMcGuire, A1 aNuttall, M1 aVirginia, Ross, A.1 aYoung, O1 aZimov, S1 aChristensen, T1 aGodduhn, A1 aMurphy, E1 aWall, Diana, H.1 aZockler, C1 aBerman, M1 aCallaghan, T1 aConvey, Peter1 aCrepin, A., S.1 aDanell, K1 aDucklow, Hugh, W.1 aForbes, B1 aKofinas, G1 aHassan, R.1 aScholes, R.1 aAsh, N. uhttps://mcm.lternet.edu/content/polar-systems00468nas a2200157 4500008004100000245002900041210002900070260003100099100001500130700002400145700002100169700001500190700002900205700001500234856006100249 2004 eng d00aAntarctic Paleolimnology0 aAntarctic Paleolimnology bKluwer Academic Publishers1 aHodgson, D1 aGibson, John, A. E.1 aDoran, Peter, T.1 aPienitz, R1 aDouglas, Marianne, S. V.1 aSmol, J.P. uhttps://mcm.lternet.edu/content/antarctic-paleolimnology00811nas a2200301 4500008004100000245004900041210004700090300001200137490000600149100001300155700001300168700001900181700001700200700001200217700001200229700001200241700002300253700002000276700001400296700002300310700002500333700001200358700001500370700001500385700001400400700001600414856007900430 2004 eng d00aDetritus, trophic dynamics and biodiversity.0 aDetritus trophic dynamics and biodiversity a584-6000 v71 aMoore, J1 aMorin, P1 aNadelhoffer, K1 aRosemound, A1 aPost, D1 aSabo, J1 aScow, K1 aVanni, Michael, J.1 aWall, Diana, H.1 aBerlow, E1 aColeman, David, C.1 aDe Ruiter, Peter, C.1 aDong, Q1 aHasting, A1 aJohnson, N1 aMcCann, K1 aMelville, K uhttps://mcm.lternet.edu/content/detritus-trophic-dynamics-and-biodiversity00594nas a2200193 4500008004100000245005000041210005000091260003100141100001200172700001400184700001300198700001400211700002100225700001600246700001500262700002900277700001500306856007900321 2004 eng d00aGeochronology of high latitude lake sediments0 aGeochronology of high latitude lake sediments bKluwer Academic Publishers1 aWolf, A1 aMiller, G1 aOlsen, C1 aForman, S1 aDoran, Peter, T.1 aHolmgren, S1 aPienitz, R1 aDouglas, Marianne, S. V.1 aSmol, J.P. uhttps://mcm.lternet.edu/content/geochronology-high-latitude-lake-sediments00667nas 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-ettl00957nas 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-biota00679nas 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-components00584nas a2200181 4500008004100000245006300041210006000104300001000164100001500174700001600189700002000205700001300225700001600238700001800254700002500272700001400297856009100311 2003 eng d00aLong-term perspectives on biodiversity-ecosystem function.0 aLongterm perspectives on biodiversityecosystem function a89-981 aSymstad, A1 aIII, Chapin1 aWall, Diana, H.1 aGross, K1 aHuenneke, L1 aMittelbach, G1 aPeters, Debra, P. C.1 aTilman, D uhttps://mcm.lternet.edu/content/long-term-perspectives-biodiversity-ecosystem-function00452nas a2200121 4500008004100000245007700041210006900118300001000187490000600197100001200203700002000215856009500235 2002 eng d00aModeling the effects of loss of soil biodiversity on ecosystem function0 aModeling the effects of loss of soil biodiversity on ecosystem f a32-490 v81 aHunt, H1 aWall, Diana, H. uhttps://mcm.lternet.edu/content/modeling-effects-loss-soil-biodiversity-ecosystem-function00582nas a2200145 4500008004100000245011800041210006900159300001200228490000700240100001400247700002400261700001200285700001200297856012700309 2002 eng d00aSynthetic aperture radar detection of the snowline on Commonwealth and Howard Glaciers, Taylor Valley, Antarctica0 aSynthetic aperture radar detection of the snowline on Commonweal a177-1830 v341 aBardel, P1 aFountain, Andrew, G1 aHall, D1 aKwok, R uhttps://mcm.lternet.edu/content/synthetic-aperture-radar-detection-snowline-commonwealth-and-howard-glaciers-taylor-valley00446nas a2200145 4500008004100000245005100041210005000092300001200142490000600154100001200160700002000172700001700192700001500209856007600224 2001 eng d00a519-529A model for nematode locomotion in soil0 a519529A model for nematode locomotion in soil a705-7160 v31 aHunt, H1 aWall, Diana, H.1 aDeCrappeo, N1 aBrenner, J uhttps://mcm.lternet.edu/content/519-529a-model-nematode-locomotion-soil00512nas a2200121 4500008004100000245010700041210006900148300000900217490000700226100001500233700001800248856012400266 2001 eng d00aAbsorption and utilization of low irradiance by cyanobacterial mats in two ice-covered Antarctic lakes0 aAbsorption and utilization of low irradiance by cyanobacterial m a5-150 v371 aHawes, Ian1 aSchwartz, A-M uhttps://mcm.lternet.edu/content/absorption-and-utilization-low-irradiance-cyanobacterial-mats-two-ice-covered-antarctic00696nas a2200157 4500008004100000245019500041210006900236300001000305490000700315100001500322700002400337700001800361700001700379700001600396856012600412 2001 eng d00aBenthic primary production in two perennially ice-covered Antarctic lakes: comparisons of annual accumulation predicted from photosynthesis models with estimates from internal growth markers0 aBenthic primary production in two perennially icecovered Antarct a18-270 v131 aHawes, Ian1 aMoorhead, Daryl, L.1 aSutherland, J1 aSchmeling, J1 aSchwartz, A uhttps://mcm.lternet.edu/content/benthic-primary-production-two-perennially-ice-covered-antarctic-lakes-comparisons-annual00477nas a2200169 4500008004100000245002200041210002200063260003000085300001000115100002000125700002000145700002400165700001900189700002200208700002300230856005400253 2001 eng d00aSoil Biodiversity0 aSoil Biodiversity aNew YorkbSpringer Verlag a47-821 aWall, Diana, H.1 aAdams, Gina, A.1 aParsons, Andrew, N.1 aChapin, F., S.1 aSala, Osvaldo, E.1 aHuber-Sannwald, E. uhttps://mcm.lternet.edu/content/soil-biodiversity00868nas 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-response00602nas a2200169 4500008004100000245007200041210006900113260003000182300001200212100002400224700001600248700002200264700001500286700001400301700001600315856010100331 2000 eng d00aExperimental Approaches to Investigate Belowground Animal Diversity0 aExperimental Approaches to Investigate Belowground Animal Divers aNew YorkbSpringer Verlag a318-3291 aFreckman, Diana, W.1 aReichman, O1 aSala, Osvaldo, E.1 aJackson, R1 aMooney, H1 aHowarth, R. uhttps://mcm.lternet.edu/content/experimental-approaches-investigate-belowground-animal-diversity00870nas 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-ecosystems00932nas 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-lakes00632nas a2200181 4500008004100000245008800041210006900129260001200198300001200210490000700222653001100229653001100240100002400251700001800275700001900293700002300312856011500335 2000 eng d00aPhytoplankton dynamics in a stably stratified Antarctic lake during winter darkness0 aPhytoplankton dynamics in a stably stratified Antarctic lake dur c10/2000 a852-8610 v3610aBiggie10awinter1 aMcKnight, Diane, M.1 aHowes, B., L.1 aTaylor, C., D.1 aGoehringer, D., D. uhttps://mcm.lternet.edu/content/phytoplankton-dynamics-stably-stratified-antarctic-lake-during-winter-darkness00523nas a2200121 4500008004100000245011300041210006900154300001200223490000700235100001500242700002400257856012000281 1999 eng d00aMcMurdo LTER: Photosynthesis in an extreme shade habitat: benthic microbial mats from Lake Hoare, Antarctica0 aMcMurdo LTER Photosynthesis in an extreme shade habitat benthic  a448-4590 v351 aHawes, Ian1 aSchwarz, Anne-Maree uhttps://mcm.lternet.edu/content/mcmurdo-lter-photosynthesis-extreme-shade-habitat-benthic-microbial-mats-lake-hoare00610nas a2200145 4500008004100000245012600041210006900167300001200236490000700248100002200255700001600277700002400293700002300317856012400340 1998 eng d00aDistribution, Community Structure, and Microhabitats of Soil Invertebrates along an Elevational Gradient in Taylor Valley0 aDistribution Community Structure and Microhabitats of Soil Inver a133-1410 v301 aPowers, Laura, E.1 aHo, Mengchi1 aFreckman, Diana, W.1 aVirginia, Ross, A. uhttps://mcm.lternet.edu/content/distribution-community-structure-and-microhabitats-soil-invertebrates-along-elevational00605nas a2200157 4500008004100000245008700041210006900128300001100197490000700208100002400215700002400239700002300263700002400286700002200310856011500332 1998 eng d00aHydrologic Processes Influencing Streamflow Variation in Fryxell Basin, Antarctica0 aHydrologic Processes Influencing Streamflow Variation in Fryxell a93-1080 v721 aConovitz, Peter, A.1 aMcKnight, Diane, M.1 aMacDonald, Lee, H.1 aFountain, Andrew, G1 aHouse, Harold, R. uhttps://mcm.lternet.edu/content/hydrologic-processes-influencing-streamflow-variation-fryxell-basin-antarctica00517nas a2200145 4500008004100000245006700041210006600108300001200174490000700186100002700193700002400220700001500244700002100259856009100280 1998 eng d00aOptical Properties of the McMurdo Dry Valley Lakes, Antarctica0 aOptical Properties of the McMurdo Dry Valley Lakes Antarctica a189-2030 v721 aHoward-Williams, Clive1 aSchwarz, Anne-Maree1 aHawes, Ian1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/optical-properties-mcmurdo-dry-valley-lakes-antarctica00480nas a2200121 4500008004100000245008300041210006900124300001200193490000700205100001500212700002700227856010400254 1998 eng d00aPrimary Production Processes in Streams of the McMurdo Dry Valleys, Antarctica0 aPrimary Production Processes in Streams of the McMurdo Dry Valle a129-1400 v721 aHawes, Ian1 aHoward-Williams, Clive uhttps://mcm.lternet.edu/content/primary-production-processes-streams-mcmurdo-dry-valleys-antarctica00556nas 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-land00492nas a2200109 4500008004100000245010400041210006900145300001200214490000700226100002200233856012700255 1998 eng d00aScience and Environmental Management in the McMurdo Dry Valleys, Southern Victoria Land, Antarctica0 aScience and Environmental Management in the McMurdo Dry Valleys  a337-3500 v721 aHarris, Colin, M. uhttps://mcm.lternet.edu/content/science-and-environmental-management-mcmurdo-dry-valleys-southern-victoria-land-antarctica00640nas a2200157 4500008004100000245011400041210006900155300001200224490000700236100002400243700002600267700002100293700002300314700002400337856012100361 1998 eng d00aStructure and composition of the photochemical apparatus of the Antarctic green alga Chlamydomonas subcaudata0 aStructure and composition of the photochemical apparatus of the  a303-3140 v561 aMorgan, Rachael, M.1 aIvanov, Alexander, G.1 aPriscu, John, C.1 aMaxwell, Denis, P.1 aHuner, Norman, P.A. uhttps://mcm.lternet.edu/content/structure-and-composition-photochemical-apparatus-antarctic-green-alga-chlamydomonas00564nas 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-synthesis00801nas a2200217 4500008004100000245015200041210006900193260002700262300001100289490000700300100002500307700002400332700002500356700002000381700002100401700002400422700002000446700002400466700001600490856007700506 1997 eng d00aEcological processes in a cold desert ecosystem: the abundance and species distribution of algal mats in glacial meltwater streams in Taylor Valley0 aEcological processes in a cold desert ecosystem the abundance an bUniversity of Colorado a108 pp0 v511 aAlger, Alexander, S.1 aMcKnight, Diane, M.1 aSpaulding, Sarah, A.1 aTate, Cathy, M.1 aShupe, Gordon, H1 aWelch, Kathleen, A.1 aEdwards, R., L.1 aAndrews, Edmund, D.1 aHouse, H.R. uhttp://instaar.colorado.edu/other/download/OP51-ECOLOGICAL-PROCESSES.pdf00594nas a2200169 4500008004100000245007400041210006900115300001200184490000700196100002400203700002000227700001700247700001800264700001700282700002200299856010300321 1997 eng d00aLinking biodiversity and ecosystem functioning of soils and sediments0 aLinking biodiversity and ecosystem functioning of soils and sedi a556-5620 v261 aFreckman, Diana, W.1 aBlackburn, T.H.1 aBrussaard, L1 aHutchings, P.1 aPalmer, M.A.1 aSnelgrove, P.V.R. uhttps://mcm.lternet.edu/content/linking-biodiversity-and-ecosystem-functioning-soils-and-sediments00462nas 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-lakes00806nas 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-antarctica00553nas a2200145 4500008004100000245008300041210006900124300001200193490000700205100002200212700002400234700002500258700002000283856010400303 1996 eng d00aGeochemistry of aquatic humic substances in the Lake Fryxell Basin, Antarctica0 aGeochemistry of aquatic humic substances in the Lake Fryxell Bas a157-1880 v341 aAiken, George, R.1 aMcKnight, Diane, M.1 aHarnish, Richard, A.1 aWershaw, Robert uhttps://mcm.lternet.edu/content/geochemistry-aquatic-humic-substances-lake-fryxell-basin-antarctica00623nas a2200157 4500008004100000245009800041210006900139300001200208490000700220100002000227700002500247700001800272700002300290700002400313856012800337 1996 eng d00aMicrocosms and Soil Ecology: Critical Linkages Between Field Studies and Modelling Food Webs0 aMicrocosms and Soil Ecology Critical Linkages Between Field Stud a694-7050 v771 aMoore, John, C.1 aDe Ruiter, Peter, C.1 aHunt, William1 aColeman, David, C.1 aFreckman, Diana, W. uhttps://mcm.lternet.edu/content/microcosms-and-soil-ecology-critical-linkages-between-field-studies-and-modelling-food-webs00502nas a2200133 4500008004100000245007700041210006900118300000800187490000700195100001600202700002300218700002400241856010300265 1996 eng d00aSoil spatial variation along a toposequence in Taylor Valley, Antarctica0 aSoil spatial variation along a toposequence in Taylor Valley Ant a1970 v771 aHo, Mengchi1 aVirginia, Ross, A.1 aFreckman, Diana, W. uhttps://mcm.lternet.edu/content/soil-spatial-variation-along-toposequence-taylor-valley-antarctica00575nas a2200133 4500008004100000245011800041210006900159300001200228490000700240100002200247700002400269700002200293856012600315 1995 eng d00aThe influence of stream channel characteristics on streamflow and annual water budgets for lakes in Taylor Valley0 ainfluence of stream channel characteristics on streamflow and an a284-2870 v301 aHouse, Harold, R.1 aMcKnight, Diane, M.1 aVon Guerard, Paul uhttps://mcm.lternet.edu/content/influence-stream-channel-characteristics-streamflow-and-annual-water-budgets-lakes-taylor00596nas a2200145 4500008004100000245010000041210006900141300001200210490000700222100002100229700002000250700002900270700002400299856012700323 1995 eng d00aMcMurdo Dry Valleys Long-Term Ecological Research (LTER): LTER automatic weather network (LAWN)0 aMcMurdo Dry Valleys LongTerm Ecological Research LTER LTER autom a276-2800 v301 aDoran, Peter, T.1 aDana, Gayle, L.1 aHastings, Jordan, Towner1 aWharton, Robert, A. uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-long-term-ecological-research-lter-lter-automatic-weather-network-lawn00496nas a2200121 4500008004100000245009200041210006900133300001200202490000700214100001500221700002400236856011400260 1995 eng d00aMcMurdo LTER: Photosynthesis in benthic cyanobacterial mats from Lake Hoare, Antarctica0 aMcMurdo LTER Photosynthesis in benthic cyanobacterial mats from  a296-2970 v301 aHawes, Ian1 aSchwarz, Anne-Maree uhttps://mcm.lternet.edu/content/mcmurdo-lter-photosynthesis-benthic-cyanobacterial-mats-lake-hoare-antarctica00450nas a2200109 4500008004100000245008000041210006900121300001200190490000700202100002900209856010200238 1995 eng d00aMcMurdo LTER: Progress with the Taylor Valley geographic information system0 aMcMurdo LTER Progress with the Taylor Valley geographic informat a297-2990 v301 aHastings, Jordan, Towner uhttps://mcm.lternet.edu/content/mcmurdo-lter-progress-taylor-valley-geographic-information-system00616nas a2200145 4500008004100000245013100041210006900172300001200241490000700253100002200260700002400282700001600306700002300322856012500345 1995 eng d00aMcMurdo LTER: Soil properties associated with nematode distribution along an elevational transect in Taylor Valley, Antarctica0 aMcMurdo LTER Soil properties associated with nematode distributi a282-2830 v301 aPowers, Laura, E.1 aFreckman, Diana, W.1 aHo, Mengchi1 aVirginia, Ross, A. uhttps://mcm.lternet.edu/content/mcmurdo-lter-soil-properties-associated-nematode-distribution-along-elevational-transect00550nas a2200145 4500008004100000245008200041210006900123300001200192490000700204100001600211700002300227700002200250700002400272856010800296 1995 eng d00aSoil chemistry along a glacial chronosequence on Andrews Ridge, Taylor Valley0 aSoil chemistry along a glacial chronosequence on Andrews Ridge T a310-3110 v301 aHo, Mengchi1 aVirginia, Ross, A.1 aPowers, Laura, E.1 aFreckman, Diana, W. uhttps://mcm.lternet.edu/content/soil-chemistry-along-glacial-chronosequence-andrews-ridge-taylor-valley00655nas a2200133 4500008004100000245017000041210006900211100002200280700002400302700002500326700002000351700002400371856012600395 1995 eng d00aStreamflow, water-temperature, and specific-conductance data for selected streams draining into Lake Fryxell, Lower Taylor Valley, Victoria Land, Antarctica, 1990-920 aStreamflow watertemperature and specificconductance data for sel1 aVon Guerard, Paul1 aMcKnight, Diane, M.1 aHarnish, Richard, A.1 aGartner, J., W.1 aAndrews, Edmund, D. uhttps://mcm.lternet.edu/content/streamflow-water-temperature-and-specific-conductance-data-selected-streams-draining-lake00478nas a2200121 4500008004100000245007500041210006900116300001200185490000700197100002900204700001900233856010400252 1994 eng d00aMcMurdo LTER: Developing a geographic information system access system0 aMcMurdo LTER Developing a geographic information system access s a246-2470 v291 aHastings, Jordan, Towner1 aButt, Anya, Z. uhttps://mcm.lternet.edu/content/mcmurdo-lter-developing-geographic-information-system-access-system00468nas a2200121 4500008004100000245007000041210006900111300001200180490000700192100001900199700002900218856009900247 1994 eng d00aMcMurdo LTER: Developing a geographic information system database0 aMcMurdo LTER Developing a geographic information system database a244-2450 v291 aButt, Anya, Z.1 aHastings, Jordan, Towner uhttps://mcm.lternet.edu/content/mcmurdo-lter-developing-geographic-information-system-database00688nas 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-dynamics00465nas a2200133 4500008004100000245005900041210005800100300001200158490000700170100002400177700002200201700002100223856008700244 1994 eng d00aMcMurdo LTER: Streamflow Measurements in Taylor Valley0 aMcMurdo LTER Streamflow Measurements in Taylor Valley a230-2320 v291 aMcKnight, Diane, M.1 aHouse, Harold, R.1 aVon Gerard, Paul uhttps://mcm.lternet.edu/content/mcmurdo-lter-streamflow-measurements-taylor-valley00587nas a2200145 4500008004100000245010700041210006900148300001200217490000700229100002200236700002400258700001600282700002300298856012000321 1994 eng d00aMcMurdo LTER:Soil and nematode distribution along an elevational gradient in Taylor Valley, Antarctica0 aMcMurdo LTERSoil and nematode distribution along an elevational  a228-2290 v291 aPowers, Laura, E.1 aFreckman, Diana, W.1 aHo, Mengchi1 aVirginia, Ross, A. uhttps://mcm.lternet.edu/content/mcmurdo-ltersoil-and-nematode-distribution-along-elevational-gradient-taylor-valley00696nas a2200157 4500008004100000245017100041210006900212300001200281490000700293100002400300700002200324700002400346700001900370700002500389856012400414 1993 eng d00aDissolved Organic Material in Dry Valley Lakes: A Comparison of Lake Fryxell, Lake Hoare, and Lake Vanda, in Physical and Biogeochemical Processes in Antarctic Lakes0 aDissolved Organic Material in Dry Valley Lakes A Comparison of L a119-1330 v591 aMcKnight, Diane, M.1 aAiken, George, R.1 aAndrews, Edmund, D.1 aBowles, E., C.1 aHarnish, Richard, A. uhttps://mcm.lternet.edu/content/dissolved-organic-material-dry-valley-lakes-comparison-lake-fryxell-lake-hoare-and-lake00573nas a2200133 4500008004100000245011000041210006900151300001200220490000700232100002100239700002500260700002700285856012700312 1989 eng d00aInorganic Nitrogen Uptake and Regeneration in Perennially Ice-Covered Lakes Fryxell and Vanda, Antarctica0 aInorganic Nitrogen Uptake and Regeneration in Perennially IceCov a335-3510 v111 aPriscu, John, C.1 aVincent, Warwick, F.1 aHoward-Williams, Clive uhttps://mcm.lternet.edu/content/inorganic-nitrogen-uptake-and-regeneration-perennially-ice-covered-lakes-fryxell-and-vanda00629nas a2200145 4500008004100000245013400041210006900175300001200244490000700256100002100263700002200284700002700306700002500333856012500358 1988 eng d00aDiel Patterns of Photosynthate Biosynthesis by Phytoplankton in Permanently Ice-Covered Antarctic Lakes Under Continuous Sunlight0 aDiel Patterns of Photosynthate Biosynthesis by Phytoplankton in  a333-3400 v101 aPriscu, John, C.1 aPriscu, Linda, R.1 aHoward-Williams, Clive1 aVincent, Warwick, F. uhttps://mcm.lternet.edu/content/diel-patterns-photosynthate-biosynthesis-phytoplankton-permanently-ice-covered-antarctic00592nas a2200145 4500008004100000245009800041210006900139300001200208490000700220100002100227700002200248700002500270700002700295856012400322 1987 eng d00aPhotosynthate Distribution by Microplankton in Permanently Ice-Covered Antarctic Desert Lakes0 aPhotosynthate Distribution by Microplankton in Permanently IceCo a260-2700 v321 aPriscu, John, C.1 aPriscu, Linda, R.1 aVincent, Warwick, F.1 aHoward-Williams, Clive uhttps://mcm.lternet.edu/content/photosynthate-distribution-microplankton-permanently-ice-covered-antarctic-desert-lakes