@article {4868, title = {An Antarctic worm and its soil ecosystem: A review of an emerging research program in ecological genomics}, journal = {Applied Soil Ecology}, volume = {193}, year = {2024}, month = {01/2024}, pages = {105110}, abstract = {

Relationships between the evolution of species and their ecosystems can be difficult to accurately assess due to the high number of confounding biological variables (e.g., biotic interactions among community members and the resulting complex relationships between genetic pathways and organism phenotypes). Thus, progress in ecological genomics by making inferences about fundamental ecological patterns and processes is hampered by high biodiversity and subsequent complex biotic interactions. Study systems that are naturally low in biological and ecological complexity, and strongly structured by abiotic drivers, can serve as models for bridging the gap between controlled mesocosm experiments and natural ecosystems. The terrestrial ecosystems of the Antarctic dry valleys have low biodiversity and constrained ecological complexity, primarily because ecological communities are so strongly shaped by physical, rather than biological, factors. The harsh constraints of the physical environment on organismal evolution and the structure of ecological communities make this an optimal natural system for disentangling the influence of specific environmental parameters on genotype/phenotype and gene by environment interactions. This work reviews the biology, evolution, and ecology of an emerging model organism, the free-living nematode Plectus murrayi, in a model ecosystem, the McMurdo Dry Valleys (MDVs) of Antarctica. In the MDVs, habitat suitability, including nutrient availability, has been shown to drive organismal (nematode) life history evolution, including growth and reproduction, primarily by way of changes in the expression of developmental genes. Changes in growth rates and reproductive schedules are accomplished primarily through alterations of nuclear rRNA gene copy number. The predicted and observed responses to natural experiments have been replicated in the laboratory, providing a synthesis of field observations and experimental evolution. Studying such natural model systems as this could fill several persistent knowledge gaps in our understanding of how genetic variation, genomic architecture, and gene regulation drive the genotype-phenotype paradigm, and the consequent effects of these drivers on ecosystem structure and functioning.

}, keywords = {LTER-MCM, ecological amplitude, ecological succession, elemental stoichiometry, extreme environments, life history evolution, model systems}, issn = {09291393}, doi = {10.1016/j.apsoil.2023.105110}, url = {https://www.sciencedirect.com/science/article/pii/S0929139323003086}, author = {Xue, Xia and Thompson, Andrew R. and Adams, Byron J.} } @article {4941, title = {Biogeographic survey of soil bacterial communities across Antarctica}, journal = {Microbiome}, volume = {12}, year = {2024}, month = {01/2024}, abstract = {

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.

}, keywords = {LTER-MCM, Antarctic Conservation Biogeographic Regions (ACBRs), Antarctic soil microbiome, bioclimatic variables, biogeography, microbial diversity, regionalization, soils}, doi = {10.1186/s40168-023-01719-3}, url = {https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-023-01719-3}, author = {Varliero, Gilda and Lebre, Pedro H. and Byron Adams and Steven L. Chown and Peter Convey and Dennis, Paul G. and Fan, Dandan and Ferrari, Belinda and Frey, Beat and Hogg, Ian D. and Hopkins, David W. and Kong, Weidong and Makhalanyane, Thulani and Matcher, Gwynneth and Newsham, Kevin K. and Stevens, Mark I. and Weigh, Katherine V. and Cowan, Don A.} } @article {4940, title = {McMurdo Dry Valley lake edge {\textquoteleft}moats{\textquoteright}: The ecological intersection between terrestrial and aquatic polar desert habitat}, journal = {Antarctic Science}, year = {2024}, month = {04/2024}, pages = {1 - 17}, abstract = {

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.

}, keywords = {LTER-MCM, connectivity, ecosystem, ice, microbial mats, transition}, issn = {0954-1020}, doi = {10.1017/S0954102024000087}, url = {https://www.cambridge.org/core/journals/antarctic-science/article/mcmurdo-dry-valley-lake-edge-moats-the-ecological-intersection-between-terrestrial-and-aquatic-polar-desert-habitats/31D94DD51E651603482A3AE6E8A52A57}, author = {Stone, Michael S. and Devlin, Shawn and Ian Hawes and Kathleen A. Welch and Michael N. Gooseff and Cristina D. Takacs-Vesbach and Rachael M. Morgan-Kiss and Byron Adams and John E. Barrett and John C. Priscu and Peter T. Doran} } @article {4928, title = {Remotely characterizing photosynthetic biocrust in snowpack-fed microhabitats of Taylor Valley, Antarctica}, journal = {Science of Remote Sensing}, year = {2024}, month = {02/2024}, pages = {100120}, abstract = {

Microbial communities are the primary drivers of carbon cycling in the McMurdo Dry Valleys of Antarctica. Dense microbial mats, consisting mainly of photosynthetic cyanobacteria, occupy aquatic areas associated with streams and lakes. Other microbial communities also occur at lower densities as patchy surface biological soil crusts (hereafter, biocrusts) across the terrestrial landscape. Multispectral satellite data have been used to model microbial mat abundance in high-density areas like stream and lake margins, but no previous studies have investigated the lower detection limits of biocrusts. Here, we describe remote sensing and field-based survey and sampling approaches to study the detectability and distribution of biocrusts in the McMurdo Dry Valleys. Using a combination of multi- and hyperspectral tools and spectral linear unmixing, we modeled the abundances of biocrust in eastern Taylor Valley. Our spectral approaches can detect low masses of biocrust material in laboratory microcosms down to biocrust concentrations of 1\% by mass. These techniques also distinguish the spectra of biocrust from both surface rock and mineral signatures from orbit. We found that biocrusts are present throughout the soils of eastern Taylor Valley and are associated with diverse underlying soil communities. The densest biocrust communities identified in this study had total organic carbon 5x greater than the content of typical arid soils. The most productive biocrusts were located downslope of melting snowpacks in unique soil ecosystems that are distinct from the surrounding arid landscape. There are similarities between the snowpack and stream sediment communities (high diversity of soil invertebrates) as well as their ecosystem properties (e.g., persistence of liquid water, high transfer of available nutrients, lower salinity from flushing) compared to the typical arid terrestrial ecosystem of the dry valleys. Our approach extends the capability of orbital remote sensing of photosynthetic communities out of the aquatic margins and into the drier soils which comprise most of this landscape. This interdisciplinary work is critical for measuring and monitoring terrestrial carbon stocks and predicting future ecosystem dynamics in this currently water-limited but increasingly dynamic Antarctic landscape, which is particularly climate-sensitive and difficult to access.

}, keywords = {LTER-MCM, Antarctica, biocrust, carbon, reflectance spectroscopy, snow, soil ecology}, issn = {26660172}, doi = {10.1016/j.srs.2024.100120}, url = {https://www.sciencedirect.com/science/article/pii/S266601722400004X}, author = {Power, Sarah N. and Salvatore, Mark R. and Eric R. Sokol and Lee F. Stanish and Borges, Schuyler R. and Byron Adams and John E. Barrett} } @article {4855, title = {Better together? The values, obstacles, opportunities, and prospects for collaborative research in environmental history}, journal = {Environmental History}, volume = {28}, year = {2023}, month = {04/2023}, pages = {269 - 299}, abstract = {

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.

}, keywords = {LTER-MCM}, issn = {1084-5453}, doi = {10.1086/723784}, url = {https://www.journals.uchicago.edu/doi/full/10.1086/723784}, author = {Alagona, Peter and Carey, Mark and Howkins, Adrian} } @article {4842, title = {Biogeography and genetic diversity of terrestrial mites in the Ross Sea region, Antarctica}, journal = {Genes}, volume = {14}, year = {2023}, month = {03/2023}, pages = {606}, abstract = {

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.

}, keywords = {LTER-MCM, Acari, Antarctic conservation, DNA barcoding, geographic isolation, speciation}, doi = {10.3390/genes14030606}, url = {https://www.mdpi.com/2073-4425/14/3/606}, author = {Gemma E. Collins and Young, Monica R. and Peter Convey and Steven L. Chown and Craig S Cary and Byron Adams and Diana H. Wall and Hogg, Ian D.} } @article {4844, title = {Causes and characteristics of electrical resistivity variability in shallow (<4 m) soils in Taylor Valley, East Antarctica}, journal = {Journal of Geophysical Research: Earth Surface}, volume = {128}, year = {2023}, month = {02/2023}, pages = {e2022JF006696}, abstract = {

Airborne electromagnetic surveys collected in December 2011 and November 2018 and three soil sampling transects were used to analyze the spatial heterogeneity of shallow (\<4 m) soil properties in lower Taylor Valley (TV), East Antarctica. Soil resistivities from 2011 to 2018 ranged from \∼33 Ωm to \∼3,500 Ωm with 200 Ωm assigned as an upper boundary for brine-saturated sediments. Elevations below \∼50 m above sea level (masl) typically exhibit the lowest resistivities with resistivity increasing at high elevations on steeper slopes. Soil water content was empirically estimated from electrical resistivities using Archie\&$\#$39;s Law and range from \∼\<1\% to \∼68\% by volume. An increase in silt- and clay-sized particles at low elevations increases soil porosity but decreases hydraulic conductivity, promoting greater residence times of soil water at low elevations near Lake Fryxell. Soil resistivity variability between 2011 and 2018 shows soils at different stages of soil freeze-thaw cycles, which are caused predominantly by solar warming of soils as opposed to air temperature. This study furthers the understanding of the hydrogeologic structure of the shallow subsurface in TV and identifies locations of soils that are potentially prone to greater rates of thaw and resulting ecosystem homogenization of soil properties from projected increases in hydrological connectivity across the region over the coming decades.

}, keywords = {LTER-MCM, active layer, airborne electromagnetic surveys, McMurdo Dry Valleys, permafrost dynamics}, issn = {2169-9003}, doi = {10.1029/2022JF006696}, url = {https://onlinelibrary.wiley.com/doi/10.1029/2022JF006696}, author = {Gutterman, William S. and Peter T. Doran and Ross A. Virginia and John E. Barrett and Myers, Krista F. and Tulaczyk, Slawek M. and Foley, Neil T. and Jill A. Mikucki and Hilary A. Dugan and Grombacher, Denys and Bording, Thue S. and Auken, E.} } @article {4944, title = {Change at 85 degrees south: Shackleton Glacier region proglacial lakes from 1960 to 2020}, journal = {Annals of Glaciology}, year = {2023}, month = {05/2023}, abstract = {

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

}, keywords = {LTER-MCM, Antarctic glaciology, climate change, meltwater chemistry}, issn = {0260-3055}, doi = {10.1017/aog.2023.27}, url = {https://www.cambridge.org/core/journals/annals-of-glaciology/article/change-at-85-degrees-south-shackleton-glacier-region-proglacial-lakes-from-1960-to-2020/565D96AD7AE72BD22C49CCB772867AC4}, author = {Melisa A. Diaz and Christopher B. Gardner and Elliot, David H. and Byron Adams and W. Berry Lyons} } @article {4942, title = {The distribution of surface soil moisture over space and time in eastern Taylor Valley, Antarctica}, journal = {Remote Sensing}, volume = {15}, year = {2023}, month = {06/2023}, pages = {3170}, abstract = {

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

}, keywords = {LTER-MCM, Dry valleys, ecology, hydrology, remote sensing, soil moisture}, doi = {10.3390/rs15123170}, url = {https://www.mdpi.com/2072-4292/15/12/3170}, author = {Salvatore, Mark R. and Barrett, John E. and Fackrell, Laura E. and Sokol, Eric R. and Levy, Joseph S. and Kuentz, Lily C. and Gooseff, Michael N. and Adams, Byron J. and Power, Sarah N. and Knightly, J. Paul and Matul, Haley M. and Szutu, Brian and Doran, Peter T.} } @article {4833, title = {Ecological stoichiometry drives the evolution of soil nematode life history traits}, journal = {Soil Biology and Biochemistry}, volume = {177}, year = {2023}, month = {02/2023}, pages = {108891}, abstract = {

Ecological stoichiometry is a useful theoretical framework for understanding the sources and controls on nutrient availability that structure the composition and diversity of biotic communities. One such relationship is that organismal development rate is positively linked to cellular Phosphorus (P). We hypothesized that P availability, relative to other nutrients, e.g., nitrogen and carbon, would drive the evolution of traits associated with organismal growth and development. We examined the effects of P availability both in situ and in vitro, on free-living soil nematodes. We found that P-deficient environments produce predictable changes in the ecology and evolution of important life history traits. Our results identify altered rRNA gene copy number and subsequent changes in gene expression and protein synthesis as mechanisms by which P-deficiency influences these traits. These findings have important implications for explaining soil ecological and evolutionary patterns across multiple levels of organization, including the structure and functioning of organisms, populations, communities, and ecosystems.

}, keywords = {LTER-MCM, elemental stoichiometry, growth rate hypothesis, life history theory, molecular evolution, nematoda, rRNA}, doi = {10.1016/j.soilbio.2022.108891}, url = {https://www.sciencedirect.com/science/article/pii/S0038071722003480}, author = {Xue, Xia and Bishwo N. Adhikari and Ball, Becky and John E. Barrett and Miao, Jinxin and Perkes, Ammon and Martin, Mac and Breana L. Simmons and Diana H. Wall and Byron Adams} } @article {4839, title = {Impact of meltwater flow intensity on the spatiotemporal heterogeneity of microbial mats in the McMurdo Dry Valleys, Antarctica}, journal = {ISME Communications}, volume = {3}, year = {2023}, month = {01/2023}, pages = {3}, abstract = {

The meltwater streams of the McMurdo Dry Valleys are hot spots of biological diversity in the climate-sensitive polar desert landscape. Microbial mats, largely comprised of cyanobacteria, dominate the streams which flow for a brief window of time (~10 weeks) over the austral summer. These communities, critical to nutrient and carbon cycling, display previously uncharacterized patterns of rapid destabilization and recovery upon exposure to variable and physiologically detrimental conditions. Here, we characterize changes in biodiversity, transcriptional responses and activity of microbial mats in response to hydrological disturbance over spatiotemporal gradients. While diverse metabolic strategies persist between marginal mats and main channel mats, data collected from 4 time points during the austral summer revealed a homogenization of the mat communities during the mid-season peak meltwater flow, directly influencing the biogeochemical roles of this stream ecosystem. Gene expression pattern analyses identified strong functional sensitivities of nitrogen-fixing marginal mats to changes in hydrological activities. Stress response markers detailed the environmental challenges of each microhabitat and the molecular mechanisms underpinning survival in a polar desert ecosystem at the forefront of climate change. At mid and end points in the flow cycle, mobile genetic elements were upregulated across all mat types indicating high degrees of genome evolvability and transcriptional synchronies. Additionally, we identified novel antifreeze activity in the stream microbial mats indicating the presence of ice-binding proteins (IBPs). Cumulatively, these data provide a new view of active intra-stream diversity, biotic interactions and alterations in ecosystem function over a high-flow hydrological regime.

}, keywords = {LTER-MCM}, doi = {10.1038/s43705-022-00202-8}, url = {https://www.nature.com/articles/s43705-022-00202-8}, author = {Zoumplis, Angela and Kolody, Bethany C. and Kaul, Drishti and Zheng, Hong and Venepally, Pratap and Diane M. McKnight and Cristina D. Takacs-Vesbach and DeVries, Arthur L. and Allen, Andrew E.} } @article {4867, title = {Long-term changes in concentration and yield of riverine dissolved silicon from the poles to the tropics}, journal = {Global Biogeochemical Cycles}, year = {2023}, month = {08/2023}, abstract = {

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.

}, keywords = {LTER-MCM, biogeochemistry, river, silica, silicon, stream, trends}, issn = {0886-6236}, doi = {10.1029/2022GB007678}, url = {https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GB007678}, author = {Jankowski, Kathi Jo and Johnson, Keira and Sethna, Lienne and Julian, Paul and Wymore, Adam S. and Shogren, Arial J. and Thomas, Patrick K. and Sullivan, Pamela L. and Diane M. McKnight and McDowell, William H. and Heindel, Ruth C and Jones, Jeremy B. and Wollheim, Wilfred and Abbott, Benjamin and Deegan, Linda and Carey, Joanna C.} } @article {4841, title = {Postglacial adaptations enabled colonization and quasi-clonal dispersal of ammonia-oxidizing archaea in modern European large lakes}, journal = {Science Advances}, volume = {9}, year = {2023}, month = {02/2023}, pages = {eadc9392}, abstract = {

Ammonia-oxidizing archaea (AOA) play a key role in the aquatic nitrogen cycle. Their genetic diversity is viewed as the outcome of evolutionary processes that shaped ancestral transition from terrestrial to marine habitats. However, current genome-wide insights into AOA evolution rarely consider brackish and freshwater representatives or provide their divergence timeline in lacustrine systems. An unbiased global assessment of lacustrine AOA diversity is critical for understanding their origins, dispersal mechanisms, and ecosystem roles. Here, we leveraged continental-scale metagenomics to document that AOA species diversity in freshwater systems is remarkably low compared to marine environments. We show that the uncultured freshwater AOA, \“Candidatus Nitrosopumilus limneticus,\” is ubiquitous and genotypically static in various large European lakes where it evolved 13 million years ago. We find that extensive proteome remodeling was a key innovation for freshwater colonization of AOA. These findings reveal the genetic diversity and adaptive mechanisms of a keystone species that has survived clonally in lakes for millennia.

}, keywords = {LTER-MCM}, doi = {10.1126/sciadv.adc9392}, url = {https://www.science.org/doi/10.1126/sciadv.adc9392}, author = {Ngugi, David Kamanda and Salcher, Michaela M. and Andrei, Adrian-Stefan and Ghai, Rohit and Klotz, Franziska and Chiriac, Maria-Cecilia and Ionescu, Danny and B{\"u}sing, Petra and Grossart, Hans-Peter and Xing, Peng and John C. Priscu and Alymkulov, Salmor and Pester, Michael} } @article {4943, title = {Strong dispersal limitation of microbial communities at Shackleton Glacier, Antarctica}, journal = {mSystems}, volume = {8}, year = {2023}, month = {01/2023}, abstract = {

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.

}, keywords = {LTER-MCM, community assembly, determinism, dispersal, niche, stochasticity}, doi = {10.1128/msystems.01254-22}, url = {https://journals.asm.org/doi/full/10.1128/msystems.01254-22}, author = {Lemoine, Nathan P. and Byron Adams and Melisa A. Diaz and Dragone, Nicholas B. and Franco, Andr{\'e} L. C. and Noah Fierer and W. Berry Lyons and Hogg, Ian D. and Diana H. Wall}, editor = {Lurgi, Miguel} } @article {4840, title = {Temperature response of metabolic activity of an Antarctic nematode}, journal = {Biology}, volume = {12}, year = {2023}, month = {01/2023}, pages = {109}, abstract = {

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.

}, keywords = {LTER-MCM, Antarctica, carbon cycling, climate change, nematode, respiration rates, soil temperature}, doi = {10.3390/biology12010109}, url = {https://www.mdpi.com/2079-7737/12/1/109}, author = {Robinson, Colin Michael and Hansen, Lee D. and Xue, Xia and Adams, Byron J.} } @article {4713, title = {Blowin{\textquoteright} in the wind: Dispersal, structure, and metacommunity dynamics of aeolian diatoms in the McMurdo Sound region, Antarctica}, journal = {Journal of Phycology}, volume = {58}, year = {2022}, month = {02/2022}, pages = {36-54}, abstract = {

Diatom metacommunities are structured by environmental, historical, and spatial factors that are often attributed to organism dispersal. In the McMurdo Sound region (MSR) of Antarctica, wind connects aquatic habitats through delivery of inorganic and organic matter. We evaluated the dispersal of diatoms in aeolian material and its relation to the regional diatom metacommunity using light microscopy and 18S rRNA high-throughput sequencing. The concentration of diatoms ranged from 0 to 8.76 * 106 valves \· g-1 dry aeolian material. Up to 15\% of whole cells contained visible protoplasm, indicating that up to 3.43 * 104 potentially viable individuals could be dispersed in a year to a single 2 cm2\ site. Diatom DNA and RNA was detected at each site, reinforcing the likelihood that we observed dispersal of viable diatoms. Of the 50 known morphospecies in the MSR, 72\% were identified from aeolian material using microscopy. Aeolian community composition varied primarily by site. Meanwhile, each aeolian community was comprised of morphospecies found in aquatic communities from the same lake basin. These results suggest that aeolian diatom dispersal in the MSR is spatially structured, is predominantly local, and connects local aquatic habitats via a shared species pool. Nonetheless, aeolian community structure was distinct from that of aquatic communities, indicating that intrahabitat dispersal and environmental filtering also underlie diatom metacommunity dynamics. The present study confirms that a large number of diatoms are passively dispersed by wind across a landscape characterized by aeolian processes, integrating the regional flora and contributing to metacommunity structure and landscape connectivity.

}, keywords = {LTER-MCM, 18S rRNA, airborne, algae, assembly, Bacillariophyta, biogeography, connectivity, high-throughput sequencing}, issn = {0022-3646}, doi = {10.1111/jpy.13223}, url = {https://onlinelibrary.wiley.com/doi/10.1111/jpy.13223}, author = {Schulte, Nicholas O. and Khan, Alia L. and Smith, Emma W. and Zoumplis, Angela and Kaul, Drishti and Allen, Andrew E. and Adams, Byron J. and Diane M. McKnight} } @article {4826, title = {Community assembly in the wake of glacial retreat: A meta-analysis}, journal = {Global Change Biology}, year = {2022}, month = {09/2022}, abstract = {

Antarctic biodiversity faces an unknown future with a changing climate. Most terrestrial biota is restricted to limited patches of ice-free land in a sea of ice, where they are adapted to the continent\&$\#$39;s extreme cold and wind and exploit microhabitats of suitable conditions. As temperatures rise, ice-free areas are predicted to expand, more rapidly in some areas than others. There is high uncertainty as to how species\&$\#$39; distributions, physiology, abundance, and survivorship will be affected as their habitats transform. Here we use current knowledge to propose hypotheses that ice-free area expansion (i) will increase habitat availability, though the quality of habitat will vary; (ii) will increase structural connectivity, although not necessarily increase opportunities for species establishment; (iii) combined with milder climates will increase likelihood of non-native species establishment, but may also lengthen activity windows for all species; and (iv) will benefit some species and not others, possibly resulting in increased homogeneity of biodiversity. We anticipate considerable spatial, temporal, and taxonomic variation in species responses, and a heightened need for interdisciplinary research to understand the factors associated with ecosystem resilience under future scenarios. Such research will help identify at-risk species or vulnerable localities and is crucial for informing environmental management and policymaking into the future.

}, keywords = {LTER-MCM, chronosequence, climate change, community assembly, deglaciation, ecological succession, glacial forefields, soil ecosystems}, doi = {10.1111/gcb.16427}, url = {https://onlinelibrary.wiley.com/doi/10.1111/gcb.16427}, author = {Pothula, Satyendra K. and Byron Adams} } @article {4836, title = {A draft mitogenome of Plectus murrayi}, journal = {Journal of Nematology}, volume = {54}, year = {2022}, month = {02/2022}, abstract = {

Plectus murrayi is a free-living microbivorous nematode endemic to Antarctic soils. Our draft assembly of its mitogenome was 15,656 bp long, containing 12 protein-coding, eight transfer RNA (tRNA), and two ribosomal RNA (rRNA) genes. Mitophylogenomic analyses extend our understanding of mitochondrial evolution in Nematoda

}, keywords = {LTER-MCM, Antarctica, genome decay, genomics, mitochondrial genome, MitoZ, phylogeny}, doi = {10.2478/jofnem-2022-0035}, url = {https://www.sciendo.com/article/10.2478/jofnem-2022-0035https://www.sciendo.com/pdf/10.2478/jofnem-2022-0035}, author = {Xue, Xia and Adams, Byron J. and Dilman, Adler R.} } @thesis {4835, title = {Effect of climate history on the genetic structure of an Antarctic soil nematode}, volume = {MS}, year = {2022}, month = {12/2022}, school = {Brigham Young University}, type = {Master{\textquoteright}s thesis}, address = {Provo, UT, USA}, abstract = {

Historical climate disturbances such as glacial cycling and fluctuating stream, lake, and sea levels strongly influence the distribution and evolutionary trajectories of Antarctic terrestrial species. Antarctic invertebrates, with limited long-range mobility, including the ubiquitous sentinel nematode species Scottnema lindsayae, are especially sensitive to climate disturbances. We tested hypotheses associated with the historical geographic and population genetic structure of this species as it occurs across the McMurdo Dry Valleys (MDVs) of Antarctica. In order to reconstruct the influence of climate disturbance and ecological conditions on this species, partial mitochondrial COI gene sequences were sequenced and analyzed from individual S. lindsayae collected from sites across the MDVs reflecting a opposing gradients of climate disturbance during the Last Glacial Maximum (LGM). We found that populations were strongly geomorphic barriers with distinct haplotypes associated with valleys except among valleys that experienced glacial advance and retreat during the LGM. One monophyletic clade corresponds with valley systems that were undisturbed during the LGM indicating putative refugia areas. A second monophyletic clade corresponds to recent dispersal and expansion of evolutionarily younger populations into valleys that were strongly reworked by glacial activity during the LGM. Our work shows that contemporary populations of these animals are strongly structured by prior climate history. Such findings can be useful for interpreting long-term monitoring of demographic shifts of soil organisms in response to changing climate trends in the McMurdo Dry Valleys.

}, keywords = {LTER-MCM, Antarctica, biogeography, climate disturbance, evolution, McMurdo Dry Valleys, polar, population genetics}, url = {http://hdl.lib.byu.edu/1877/etd12622}, author = {Jackson, Abigail C.}, editor = {Adams, Byron J.} } @article {4718, title = {Elevational constraints on the composition and genomic attributes of microbial communities in Antarctic soils}, journal = {mSystems}, volume = {7}, year = {2022}, month = {01/2022}, pages = {e01330-21}, abstract = {

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.

}, keywords = {LTER-MCM, Antarctica, microbial ecology, soil microbiology, soils}, doi = {10.1128/msystems.01330-21}, url = {https://journals.asm.org/doi/full/10.1128/msystems.01330-21}, author = {Dragone, Nicholas B. and Henley, Jessica B. and Holland-Moritz, Hannah and Melisa A. Diaz and Hogg, Ian D. and W. Berry Lyons and Diana H. Wall and Byron Adams and Noah Fierer}, editor = {Mackelprang, Rachel} } @article {4825, title = {Glacial legacies: Microbial communities of Antarctic refugia}, journal = {Biology}, volume = {11}, year = {2022}, month = {10/2022}, pages = {1440}, abstract = {

In the cold deserts of the McMurdo Dry Valleys (MDV) the suitability of soil for microbial life is determined by both contemporary processes and legacy effects. Climatic changes and accompanying glacial activity have caused local extinctions and lasting geochemical changes to parts of these soil ecosystems over several million years, while areas of refugia may have escaped these disturbances and existed under relatively stable conditions. This study describes the impact of historical glacial and lacustrine disturbance events on microbial communities across the MDV to investigate how this divergent disturbance history influenced the structuring of microbial communities across this otherwise very stable ecosystem. Soil bacterial communities from 17 sites representing either putative refugia or sites disturbed during the Last Glacial Maximum (LGM) (22\–17 kya) were characterized using 16 S metabarcoding. Regardless of geographic distance, several putative refugia sites at elevations above 600 m displayed highly similar microbial communities. At a regional scale, community composition was found to be influenced by elevation and geographic proximity more so than soil geochemical properties. These results suggest that despite the extreme conditions, diverse microbial communities exist in these putative refugia that have presumably remained undisturbed at least through the LGM. We suggest that similarities in microbial communities can be interpreted as evidence for historical climate legacies on an ecosystem-wide scale.

}, keywords = {LTER-MCM, Antarctica, McMurdo Dry Valleys, metabarcoding, microbial communities, refugia, soil biodiversity}, doi = {10.3390/biology11101440}, url = {https://www.mdpi.com/2079-7737/11/10/1440}, author = {Jackson, Abigail C. and Jorna, Jesse and Chaston, J and Adams, Byron J.} } @article {4689, title = {Response of Antarctic soil fauna to climate-driven changes since the Last Glacial Maximum}, journal = {Global Change Biology}, volume = {28}, year = {2022}, month = {01/2022}, abstract = {

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.

}, keywords = {LTER-MCM, biodiversity, climate change, glacial retreat, nematodes, Shackleton Glacier, soil invertebrates}, issn = {1354-1013}, doi = {10.1111/gcb.15940}, url = {https://onlinelibrary.wiley.com/doi/10.1111/gcb.15940}, author = {Franco, Andr{\'e} L. C. and Byron Adams and Melisa A. Diaz and Lemoine, Nathan P. and Dragone, Nicholas B. and Noah Fierer and W. Berry Lyons and Hogg, Ian D. and Diana H. Wall} } @article {4735, title = {Ten scientific messages on risks and opportunities for life in the Antarctic}, year = {2022}, month = {02/2022}, institution = {Antarctic Environments Portal}, abstract = {

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.

}, keywords = {LTER-MCM}, url = {https://environments.aq/publications/ten-scientific-messages-on-risks-and-opportunities-for-life-in-the-antarctic/}, author = {Gutt, Julian and Isla, Enrique and Xavier, Jos{\'e} C. and Adams, Byron J. and Ahn, In-Young and Cheng, C.-H. Christina and Colesie, Claudia and Cummings, Vonda J. and Griffiths, Huw J. and Hogg, Ian D. and McIntyre, Trevor and Meiners, Klaus M. and Pearce, David A. and Lloyd S. Peck and Piepenburg, Dieter and Reisinger, Ryan R. and Saba, Grace and Schloss, Irene R. and Signori, Camila N. and Smith, Craig R. and Vacchi, Marino and Verde, Cinzia and Diana H. Wall} } @article {4838, title = {The time is right for an Antarctic biorepository network}, journal = {Proceedings of the National Academy of Sciences}, volume = {119}, year = {2022}, month = {12/2022}, abstract = {

Antarctica is a central driver of the Earth\’s climate and health. The Southern Ocean surrounding Antarctica serves as a major sink for anthropogenic CO2 and heat, and the loss of Antarctic ice sheets contributes significantly to sea level rise and will continue to do so as the loss of ice sheets accelerates, with sufficient water stores to raise sea levels by 58 m. Antarctica\&$\#$39;s marine environment is home to a number of iconic species, and the terrestrial realm harbors a remarkable oasis for life, much of which has yet to be discovered. Distinctive oceanographic features of the Southern Ocean\—including the Antarctic Circumpolar Current, the Antarctic Polar Front, and exceptional depths surrounding the continent\—coupled with chronically cold temperatures have fostered the evolution of a vast number of uniquely coldadapted species, many of which are found nowhere else on the Earth. The Antarctic marine biota, for example, displays the highest level of species endemism on the Earth. However, warming, ocean acidification, pollution, and commercial exploitation threaten the integrity of Antarctic ecosystems. Understanding changes in the biota and its capacities for adaptation is imperative for establishing effective policies for mitigating the impacts of climate change and sustaining the Antarctic ecosystems that are vital to global health.

}, keywords = {LTER-MCM}, issn = {0027-8424}, doi = {10.1073/pnas.2212800119}, url = {https://www.pnas.org/doi/10.1073/pnas.2212800119}, author = {O{\textquoteright}Brien, Kristin M. and Crockett, Elizabeth L. and Byron Adams and Amsler, Charles D. and Appiah-Madson, Hannah J. and Collins, Allen and Desvignes, Thomas and Detrich, H. William and Distel, Daniel L. and Eppley, Sarah M. and Frable, Benjamin W. and Franz, Nico M. and Grim, Jeffrey M. and Kocot, Kevin M. and Mahon, Andrew R. and Mayfield-Meyer, Teresa J. and Jill A. Mikucki and Moser, William E. and Schmull, Michaela and Seid, Charlotte A. and Smith, Craig R. and Todgham, Anne E. and Watkins-Colwell, Gregory J.} } @article {4578, title = {Antarctic ecosystems in transition {\textendash} life between stresses and opportunities}, journal = {Biological Reviews}, year = {2021}, month = {06/2021}, abstract = {

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.

}, keywords = {LTER-MCM, adaptation, benthic dynamism, biogeochemical cycles, climate change, invasion, new habitats, ocean acidification, Primary production, range shifts, sea ice}, doi = {10.1111/brv.12679}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/brv.12679}, author = {Gutt, Julian and Isla, Enrique and Xavier, Jos{\'e} C. and Adams, Byron J. and Ahn, In-Young and Cheng, C.-H. Christina and Colesie, Claudia and Cummings, Vonda J. and di Prisco, Guido and Griffiths, Huw J. and Ian Hawes and Hogg, Ian D. and McIntyre, Trevor and Meiners, Klaus M. and Pearce, David A. and Lloyd S. Peck and Piepenburg, Dieter and Reisinger, Ryan R. and Saba, Grace and Schloss, Irene R. and Signori, Camila N. and Smith, Craig R. and Vacchi, Marino and Verde, Cinzia and Diana H. Wall} } @article {4585, title = {Antarctic water tracks: Microbial community responses to variation in soil moisture, pH, and salinity}, journal = {Frontiers in Microbiology}, volume = {12}, year = {2021}, month = {01/2021}, abstract = {

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

}, keywords = {LTER-MCM, Antarctica, extremophiles, Mars analog, microbial ecology, water tracks}, doi = {10.3389/fmicb.2021.616730}, url = {https://www.frontiersin.org/articles/10.3389/fmicb.2021.616730}, author = {George, Scott F. and Noah Fierer and Joseph S. Levy and Byron Adams} } @article {4627, title = {Connectivity: Insights from the U.S. Long Term Ecological Research Network}, journal = {Ecosphere}, volume = {12}, year = {2021}, month = {05/2021}, pages = {e03432}, abstract = {

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.

}, keywords = {LTER-MCM, alpine tundra, Antarctic polar desert, arid grassland, arid shrubland, coastal, estuary, salt marsh, Special Feature: Forecasting Earth{\textquoteright}s Ecosystems with Long-Term Ecological Research, urban ecosystem}, issn = {2150-8925}, doi = {10.1002/ecs2.v12.510.1002/ecs2.3432}, url = {https://onlinelibrary.wiley.com/doi/10.1002/ecs2.3432}, author = {Iwaniec, David M. and Michael N. Gooseff and Suding, Katharine N. and Johnson, David Samuel and Reed, Daniel C. and Debra P. C. Peters and Byron Adams and John E. Barrett and Bestelmeyer, Brandon T. and Castorani, Max C. N. and Cook, Elizabeth M. and Davidson, Melissa J. and Groffman, Peter M. and Hanan, Niall P. and Huenneke, L and Johnson, Pieter T. J. and Diane M. McKnight and Miller, Robert J. and Okin, Gregory S. and Preston, Daniel L. and Rassweiler, Andrew and Ray, Chris and Osvaldo E. Sala and Schooley, Robert and Seastedt, Timothy and Spasojevic, Marko J. and Vivoni, Enrique R.} } @article {4576, title = {Diatoms define a novel freshwater biogeography of the Antarctic}, journal = {Ecography}, volume = {44}, year = {2021}, month = {01/2021}, pages = {1-13}, abstract = {

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.

}, keywords = {LTER-MCM, Antarctica, biogeography, diatoms, endemism, freshwater, lake}, doi = {10.1111/ecog.05374}, url = {https://onlinelibrary.wiley.com/doi/10.1111/ecog.05374}, author = {Elie Verleyen and Bart Van de Vijver and Tytgat, Bjorn and Pinseel, Eveline and Hodgson, Dominic A. and Kopalov{\'a}, Kate{\v r}ina and Steven L. Chown and Van Ranst, Eric and Imura, Satoshi and Kudoh, Sakae and Van Nieuwenhuyze, Wim and Sabbe, Koen and Vyverman, Wim} } @article {4636, title = {Exploring the boundaries of microbial habitability in soil}, journal = {Journal of Geophysical Research: Biogeosciences}, volume = {126}, year = {2021}, month = {06/2021}, abstract = {

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.

}, keywords = {LTER-MCM, Antarctica, astrobiology, bacteria, extremophiles, fungi, soils}, issn = {2169-8953}, doi = {10.1029/2020JG006052}, url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020JG006052}, author = {Dragone, Nicholas B. and Melisa A. Diaz and Hogg, Ian D. and W. Berry Lyons and W. Andrew Jackson and Diana H. Wall and Adams, Byron J. and Noah Fierer} } @article {4583, title = {Genome analysis of Plectus murrayi, a nematode from continental Antarctica}, journal = {G3 Genes|Genomes|Genetics}, year = {2021}, month = {01/2021}, abstract = {

Plectus murrayi is one of the most common and locally abundant invertebrates of continental Antarctic ecosystems. Because it is readily cultured on artificial medium in the laboratory and highly tolerant to an extremely harsh environment, Plectus murrayi is emerging as a model organism for understanding the evolutionary origin and maintenance of adaptive responses to multiple environmental stressors, including freezing and desiccation. The de novo assembled genome of Plectus murrayi contains 225.741 million base pairs and a total of 14,689 predicted genes. Compared to Caenorhabditis elegans, the architectural components of Plectus murrayi are characterized by a lower number of protein-coding genes, fewer transposable elements, but more exons, than closely related taxa from less harsh environments. We compared the transcriptomes of lab-reared Plectus murrayi with wild-caught Plectus murrayi and found genes involved in growth and cellular processing were up-regulated in lab-cultured Plectus murrayi, while a few genes associated with cellular metabolism and freeze tolerance were expressed at relatively lower levels. Preliminary comparative genomic and transcriptomic analyses suggest that the observed constraints on P. murrayi genome architecture and functional gene expression, including genome decay and intron retention, may be an adaptive response to persisting in a biotically simplified, yet consistently physically harsh environment.

}, keywords = {LTER-MCM, gene loss, genome architecture, genome assembly, genome decay, Plectus murrayi}, doi = {10.1093/g3journal/jkaa045}, url = {https://academic.oup.com/g3journal/advance-article/doi/10.1093/g3journal/jkaa045/6044189}, author = {Xue, Xia and Suvorov, Anton and Fujimoto, Stanley and Dilman, Adler R. and Byron Adams} } @article {4646, title = {Geochemical zones and environmental gradients for soils from the central Transantarctic Mountains, Antarctica}, journal = {Biogeosciences}, volume = {18}, year = {2021}, month = {03/2021}, pages = {1629 - 1644}, abstract = {

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.

}, keywords = {LTER-MCM}, doi = {10.5194/bg-18-1629-2021}, url = {https://bg.copernicus.org/articles/18/1629/2021/}, author = {Melisa A. Diaz and Christopher B. Gardner and Welch, Susan A. and W. Andrew Jackson and Adams, Byron J. and Diana H. Wall and Hogg, Ian D. and Noah Fierer and W. Berry Lyons} } @article {4768, title = {Patterns and trends of organic matter processing and transport: Insights from the US Long-term Ecological Research Network}, journal = {Climate Change Ecology}, volume = {2}, year = {2021}, month = {12/2021}, pages = {100025}, abstract = {

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.

}, keywords = {LTER-MCM, coupled biogeochemical cycles, cross-site synthesis, organic matter composition, organic matter storage, stabilization, transport}, issn = {26669005}, doi = {10.1016/j.ecochg.2021.100025}, url = {https://www.sciencedirect.com/science/article/pii/S2666900521000253}, author = {Harms, Tamara K. and Groffman, Peter M. and Aluwihare, Lihini and Craft, Christopher and Wieder, William R and Hobbie, S and Baer, Sara G. and J.M. Blair and Frey, Serita D. and Remucal, Christina K. and Rudgers, Jennifer A. and Collins, SL and Kominoski, John S. and Ball, Becky and John C. Priscu and John E. Barrett} } @article {4645, title = {Phagotrophic protists and their associates: Evidence for preferential grazing in an abiotically driven soil ecosystem}, journal = {Microorganisms}, volume = {9}, year = {2021}, month = {08/2021}, pages = {1555}, abstract = {

The complex relationship between ecosystem function and soil food web structure is governed by species interactions, many of which remain unmapped. Phagotrophic protists structure soil food webs by grazing the microbiome, yet their involvement in intraguild competition, susceptibility to predator diversity, and grazing preferences are only vaguely known. These species-dependent interactions are contextualized by adjacent biotic and abiotic processes, and thus obfuscated by typically high soil biodiversity. Such questions may be investigated in the McMurdo Dry Valleys (MDV) of Antarctica because the physical environment strongly filters biodiversity and simplifies the influence of abiotic factors. To detect the potential interactions in the MDV, we analyzed the co-occurrence among shotgun metagenome sequences for associations suggestive of intraguild competition, predation, and preferential grazing. In order to control for confounding abiotic drivers, we tested co-occurrence patterns against various climatic and edaphic factors. Non-random co-occurrence between phagotrophic protists and other soil fauna was biotically driven, but we found no support for competition or predation. However, protists predominately associated with Proteobacteria and avoided Actinobacteria, suggesting grazing preferences were modulated by bacterial cell-wall structure and growth rate. Our study provides a critical starting-point for mapping protist interactions in native soils and highlights key trends for future targeted molecular and culture-based approaches.

}, keywords = {LTER-MCM, Antarctica, co-occurrence networks, McMurdo Dry Valleys, Rhogostoma sp., Sandona sp., soil food webs, variation partitioning}, doi = {10.3390/microorganisms9081555}, url = {https://www.mdpi.com/2076-2607/9/8/1555}, author = {Thompson, Andrew R. and Roth-Monz{\'o}n, Andrea J. and Aanderud, Zachary T. and Adams, Byron J.} } @article {4647, title = {Thermal legacy of a large paleolake in Taylor Valley, East Antarctica, as evidenced by an airborne electromagnetic survey}, journal = {The Cryosphere}, volume = {15}, year = {2021}, month = {08/2021}, pages = {3577 - 3593}, abstract = {

Previous studies of the lakes of the McMurdo Dry Valleys have attempted to constrain lake level history, and results suggest the lakes have undergone hundreds of meters of lake level change within the last 20 000 years. Past studies have utilized the interpretation of geologic deposits, lake chemistry, and ice sheet history to deduce lake level history; however a substantial amount of disagreement remains between the findings, indicating a need for further investigation using new techniques. This study utilizes a regional airborne resistivity survey to provide novel insight into the paleohydrology of the region. Mean resistivity maps revealed an extensive brine beneath the Lake Fryxell basin, which is interpreted as a legacy groundwater signal from higher lake levels in the past. Resistivity data suggest that active permafrost formation has been ongoing since the onset of lake drainage and that as recently as 1500\–4000 years BP, lake levels were over 60 m higher than present. This coincides with a warmer-than-modern paleoclimate throughout the Holocene inferred by the nearby Taylor Dome ice core record. Our results indicate Mid to Late Holocene lake level high stands, which runs counter to previous research finding a colder and drier era with little hydrologic activity throughout the last 5000 years.

}, keywords = {LTER-MCM}, doi = {10.5194/tc-15-3577-2021}, url = {https://tc.copernicus.org/articles/15/3577/2021/}, author = {Myers, Krista F. and Peter T. Doran and Tulaczyk, Slawek M. and Foley, Neil T. and Bording, Thue S. and Auken, Esben and Hilary A. Dugan and Jill A. Mikucki and Foged, Nikolaj and Grombacher, Denys and Ross A. Virginia} } @article {4488, title = {Genetic diversity of soil invertebrates corroborates timing estimates for past collapses of the West Antarctic Ice Sheet}, journal = {Proceedings of the National Academy of Sciences}, year = {2020}, month = {08/2020}, abstract = {

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.

}, keywords = {LTER-MCM, climate change, microarthropods, molecular clock, phylogeography, terrestrial biodiversity}, doi = {10.1073/pnas.2007925117}, url = {https://www.pnas.org/content/early/2020/08/19/2007925117}, author = {Gemma E. Collins and Hogg, Ian D. and Convey, Peter and Sancho, Leopoldo G. and Cowan, Don A. and W. Berry Lyons and Byron Adams and Diana H. Wall and Allan Green, T. G.} } @article {4471, title = {Geochemistry of aeolian material from the McMurdo Dry Valleys, Antarctica: Insights into Southern Hemisphere dust sources}, journal = {Earth and Planetary Science Letters}, volume = {547}, year = {2020}, month = {10/2020}, abstract = {

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

}, keywords = {LTER-MCM, aeolian material, Antarctica, major oxides, mineralogy, rare earth elements, trace elements}, doi = {10.1016/j.epsl.2020.116460}, url = {https://www.sciencedirect.com/science/article/pii/S0012821X20304040}, author = {Melisa A. Diaz and Welch, Susan A. and Sheets, J. M. and Kathleen A. Welch and Khan, Alia L. and Byron Adams and Diane M. McKnight and Craig S Cary and W. Berry Lyons} } @article {4418, title = {GIS tool to predict photosynthetically active radiation in a Dry Valley}, journal = {Antarctic Science}, year = {2020}, month = {04/2020}, abstract = {

Understanding primary productivity is a core research area of the National Science Foundation\&$\#$39;s Long-Term Ecological Research Network. This study presents the development of the GIS-based Topographic Solar Photosynthetically Active Radiation (T-sPAR) toolbox for Taylor Valley. It maps surface photosynthetically active radiation using four meteorological stations with ~20 years of data. T-sPAR estimates were validated with ground-truth data collected at Taylor Valley\&$\#$39;s major lakes during the 2014\–15 and 2015\–16 field seasons. The average daily error ranges from 0.13 mol photons m-2 day-1 (0.6\%) at Lake Fryxell to 3.8 mol photons m-2 day-1 (5.8\%) at Lake Hoare. We attribute error to variability in terrain and sun position. Finally, a user interface was developed in order to estimate total daily surface photosynthetically active radiation for any location and date within the basin. T-sPAR improves upon existing toolboxes and models by allowing for the inclusion of a statistical treatment of light attenuation due to cloud cover. The T-sPAR toolbox could be used to inform biological sampling sites based on radiation distribution, which could collectively improve estimates of net primary productivity, in some cases by up to 25\%.

}, keywords = {LTER-MCM, ArcMap, automated weather station, digital elevation model, ice-covered lakes, McMurdo Dry Valleys, R model, Taylor Valley}, doi = {10.1017/S0954102020000218}, url = {https://www.cambridge.org/core/journals/antarctic-science/article/gis-tool-to-predict-photosynthetically-active-radiation-in-a-dry-valley/BD0BE4FF6A8F3DAAF32D698797287078}, author = {Acosta, Dimitri R. and Peter T. Doran and Myers, Madeline} } @article {4420, title = {A global database of soil nematode abundance and functional group composition}, journal = {Scientific Data}, volume = {7}, year = {2020}, month = {03/2020}, abstract = {

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.

}, keywords = {LTER-MCM}, doi = {10.1038/s41597-020-0437-3}, url = {https://www.nature.com/articles/s41597-020-0437-3}, author = {van den Hoogen, Johan and Geisen, Stefan and Diana H. Wall and Wardle, D and Traunspurger, Walter and de Goede, Ron G. M. and Byron Adams and Ahmad, Wasim and Ferris, Howard and Richard D. Bardgett and Bonkowski, Michael and Campos-Herrera, Raquel and Cares, Juvenil E. and Caruso, Tancredi and de Brito Caixeta, Larissa and Chen, Xiaoyun and Costa, Sofia R. and Creamer, Rachel and da Cunha e Castro, Jos{\'e} and Dam, Marie and Djigal, Djibril and Escuer, Miguel and Griffiths, Bryan S. and Guti{\'e}rrez, Carmen and Hohberg, Karin and Kalinkina, Daria and Kardol, Paul and Kergunteuil, Alan and Korthals, Gerard and Krashevska, Valentyna and Kudrin, Alexey A. and Li, Qi and Liang, Wenju and Magilton, Matthew and Marais, Mariette and Mart{\'\i}n, Jos{\'e} Antonio Rodr{\'\i}guez and Matveeva, Elizaveta and Mayad, El Hassan and Mzough, E. and Mulder, Christian and Mullin, Peter and Neilson, Roy and Nguyen, T. A. Duong and Uffe N. Nielsen and Okada, Hiroaki and Rius, Juan Emilio Palomares and Pan, Kaiwen and Peneva, Vlada and Pellissier, Lo{\"\i}c and Carlos Pereira da Silva, Julio and Pitteloud, Camille and Powers, Thomas O. and Powers, Kirsten and Quist, Casper W. and Rasmann, Sergio and Moreno, Sara S{\'a}nchez and Scheu, Stefan and Set{\"a}l{\"a}, Heikki and Sushchuk, Anna and Tiunov, Alexei V. and Trap, Jean and Vesterg{\r a}rd, Mette and Villenave, Cecile and Waeyenberge, Lieven and Wilschut, Rutger and Wright, Daniel G. and Keith, Aidan M. and Yang, Jiue-in and Schmidt, Olaf and Bouharroud, R. and Ferji, Z. and van der Putten, Wim H. and Routh, Devin and Crowther, Thomas Ward} } @article {4439, title = {The rise of technocratic environmentalism: the United States, Antarctica, and the globalisation of the environmental impact statement}, journal = {Journal of Historical Geography}, year = {2020}, month = {05/2020}, abstract = {

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.

}, keywords = {LTER-MCM, Antarctica, Conservation, Environmental impact statements, Environmental protection, National Environmental Policy Act (NEPA)}, doi = {10.1016/j.jhg.2020.03.004}, url = {https://www.sciencedirect.com/science/article/abs/pii/S030574882030027X}, author = {Antonello, Alessandro and Howkins, Adrian} } @article {4490, title = {Shotgun metagenomics reveal a diverse assemblage of protists in a model Antarctic soil ecosystem}, journal = {Environmental Microbiology}, year = {2020}, month = {08/2020}, abstract = {

The soils of the McMurdo Dry Valleys (MDV) of Antarctica are established models for understanding fundamental processes in soil ecosystem functioning (e.g. ecological tipping points, community structuring, and nutrient cycling) because the extreme physical environment drastically reduces biodiversity and ecological complexity. Understanding the functioning of MDV soils requires in-depth knowledge of the diversity of MDV soil species. Protists, which contribute significantly to soil ecosystem functioning worldwide, remain poorly characterized in the MDV. To better assess the diversity of MDV protists, we performed shotgun metagenomics on 18 sites representing a variety of landscape features and edaphic variables. Our results show MDV soil protists are diverse at both the genus (155 of 281 eukaryote genera) and family (120) levels, but comprise only 6\% of eukaryotic reads. Protists are structured by moisture, total N, and distance from the local coast, and possess limited richness in arid (\<5\% moisture) and at high elevation sites, known drivers of communities in the MDV. High relative diversity and broad distribution of protists in our study promotes these organisms as key members of MDV soil microbiomes and the MDV as a useful system for understanding the contribution of soil protists to the structure of soil microbiomes.

}, keywords = {LTER-MCM, Antarctica, extremophiles, functional groups, metagenomics, protozoa, soil microbiology}, doi = {10.1111/1462-2920.15198}, url = {https://sfamjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1462-2920.15198}, author = {Thompson, Andrew R. and Geisen, Stefan and Byron Adams} } @article {4153, title = {Biotic interactions are an unexpected yet critical control on the complexity of an abiotically driven polar ecosystem}, journal = {Communications Biology}, volume = {2}, year = {2019}, month = {02/2019}, abstract = {

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.

}, keywords = {LTER-MCM}, doi = {10.1038/s42003-018-0274-5}, url = {https://www.nature.com/articles/s42003-018-0274-5}, author = {Charles K. Lee and Laughlin, Daniel C. and Bottos, Eric M. and Caruso, Tancredi and Joy, Kurt and John E. Barrett and Brabyn, Lars and Uffe N. Nielsen and Byron Adams and Diana H. Wall and D. W. Hopkins and Pointing, Steve B. and McDonald, Ian R. and Cowan, Don A. and Banks, Jonathan C. and Stichbury, Glen A. and Jones, Irfon and Zawar-Reza, Peyman and Katurji, Marwan and Hogg, Ian D. and Sparrow, Ashley D. and Storey, Bryan C. and Allan Green, T. G. and Craig S Cary} } @phdthesis {4761, title = {Heterotrophic protists as useful models for studying microbial food webs in a model soil ecosystem and the universality of complex unicellular life}, volume = {PhD}, year = {2019}, school = {Brigham Young University}, type = {doctoral}, address = {Provo, UT}, abstract = {

Heterotrophic protists, consisting largely of the Cercozoa, Amoebozoa, Ciliophora, Discoba and some Stramenopiles, are a poorly characterized component of life on Earth. They play an important ecological role in soil communities and provide key insights into the nature of one of life\’s most enigmatic evolutionary transitions: the development of the complex unicell. Soil ecosystems are crucial to the functioning of global biogeochemical cycles (e.g. carbon and nitrogen) but are at risk of drastic change from anthropogenic climate change. Heterotrophic protists are the primary regulators of bacterial diversity in soils and as such play integral roles in biogeochemical cycling, nutrient mobilization, and trophic cascades in food webs under stress. Understanding the nature of these changes requires examining the rates, diversity, and resiliency of interactions that occur between soil organisms. However, soils are the most taxonomically diverse ecosystems on Earth and disentangling the complexities of dynamic and varied biotic interactions in them requires a unique model system. The McMurdo Dry Valleys of Antarctica, one of the harshest terrestrial environments on Earth, serve as a model soil ecosystem owing to their highly reduced biological diversity. Exploring the functioning of heterotrophic protists in these valleys provides a way to test the applicability of this model system to other soil food webs. However, very little is known about their taxonomic diversity, which is a strong predictor of function. Therefore, I reviewed the Antarctic literature to compile a checklist of all known terrestrial heterotrophic protists in Antarctica. I found significant geographical, methodological, and taxonomic biases and outlined how to address these in future research programs. I also conducted a molecular survey of whole soil communities using 18 shotgun metagenomes representing major landscape features of the McMurdo Dry Valleys. The results revealed the dominance of Cercozoa and point to an Antarctic heterotrophic protist soil community that is taxonomically diverse and reflects the structure and composition of communities at lower latitudes. To investigate whether biotic interactions or abiotic factors were a larger driver for Antarctic heterotrophic protists, I conducted variation partitioning using environmental data (e.g. moisture, pH and electrical conductivity). Biotic variables were more significant and accounted for more of the variation than environmental variables. Taken together, it is clear that heterotrophic protists play key ecological roles in this ecosystem. Deeper insights into the ecology of these organisms in the McMurdo Dry Valleys also have implications for the search for complex unicellular life in our universe. I discuss the theoretical underpinnings of searching for these forms of life outside of Earth, conclude that they are likely to occur, and postulate how future missions could practically search for complex unicells.

}, keywords = {LTER-MCM, heterotrophic soil protists, key evolutionary innovations, life on Mars, McMurdo Dry Valleys, network analysis, shotgun metagenomics, universal complex unicellular life}, url = {https://www.proquest.com/docview/2310631977}, author = {Thompson, Andrew R.}, editor = {Adams, Byron J.} } @article {4373, title = {The hydroecology of an ephemeral wetland in the McMurdo Dry Valleys, Antarctica}, journal = {Journal of Geophysical Research: Biogeosciences}, year = {2019}, month = {11/2019}, abstract = {

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

}, keywords = {LTER-MCM, Antarctica, desert hydrology, diatom biodiversity, hyporheic interactions, wetlands}, doi = {10.1029/2019JG005153}, url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JG005153}, author = {Wlostowski, Adam and Schulte, Nicholas O. and Byron Adams and Ball, Becky and Rhea M.M. Esposito and Michael N. Gooseff and W. Berry Lyons and Uffe N. Nielsen and Ross A. Virginia and Diana H. Wall and Kathleen A. Welch and Diane M. McKnight} } @article {4140, title = {In a PICL: The sedimentary deposits and facies of perennially ice-covered lakes}, journal = {Sedimentology}, volume = {66}, year = {2019}, month = {04/2019}, abstract = {

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.

}, keywords = {LTER-MCM}, doi = {10.1111/sed.12522}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/sed.12522}, author = {Rivera-Hernandez, Frances and Sumner, Dawn Y. and Mackey, Tyler J. and Ian Hawes and Dale T. Andersen} } @article {4164, title = {Nematodes in a polar desert reveal the relative role of biotic interactions in the coexistence of soil animals}, journal = {Communications Biology}, volume = {2}, year = {2019}, month = {02/2019}, abstract = {

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.

}, keywords = {LTER-MCM}, doi = {10.1038/s42003-018-0260-y}, url = {http://www.nature.com/articles/s42003-018-0260-y}, author = {Caruso, Tancredi and Hogg, Ian D. and Uffe N. Nielsen and Bottos, Eric M. and Charles K. Lee and D. W. Hopkins and Craig S Cary and John E. Barrett and Green, T. G. Allan and Storey, Bryan C. and Diana H. Wall and Byron Adams} } @article {4374, title = {The polar regions in a 2{\textdegree}C warmer world}, journal = {Science Advances}, volume = {5}, year = {2019}, month = {12/2019}, pages = {eaaw9883}, abstract = {

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

}, keywords = {LTER-MCM}, doi = {10.1126/sciadv.aaw9883}, url = {http://advances.sciencemag.org/lookup/doi/10.1126/sciadv.aaw9883}, author = {Post, Eric and Alley, Richard B. and Christensen, Torben R. and Macias-Fauria, Marc and Forbes, Bruce C. and Michael N. Gooseff and Iler, Amy and Kerby, Jeffrey T. and Laidre, Kristin L. and Mann, Michael E. and Olofsson, Johan and Stroeve, Julienne C. and Ulmer, Fran and Ross A. Virginia and Wang, Muyin} } @article {4360, title = {Provisional checklist of terrestrial heterotrophic protists from Antarctica}, journal = {Antarctic Science}, year = {2019}, month = {11/2019}, abstract = {

Heterotrophic soil protists encompass lineages that are both evolutionarily ancient and highly diverse, providing an untapped wealth of scientific insight. Yet the diversity of free-living heterotrophic terrestrial protists is still largely unknown. To contribute to our understanding of this diversity, we present a checklist of heterotrophic protists currently reported from terrestrial Antarctica, for which no comprehensive evaluation currently exists. As a polar continent, Antarctica is especially susceptible to rising temperatures caused by anthropogenic climate change. Establishing a baseline for future conservation efforts of Antarctic protists is therefore important. We performed a literature search and found 236 taxa identified to species and an additional 303 taxa identified to higher taxonomic levels in 54 studies spanning over 100 years of research. Isolated by distance, climate and the circumpolar vortex, Antarctica is the most extreme continent on Earth: it is not unreasonable to think that it may host physiologically and evolutionarily unique species of protists, yet currently most species discovered in Antarctica are considered cosmopolitan. Additional sampling of the more extreme intra-continental zones will probably result in the discovery of more novel and unique taxa.

}, keywords = {LTER-MCM}, doi = {10.1017/S0954102019000361}, url = {https://www.cambridge.org/core/journals/antarctic-science/article/provisional-checklist-of-terrestrial-heterotrophic-protists-from-antarctica/DC08D89ABDC5AF2CC83E38B1C6F1F78C}, author = {Thompson, Andrew R. and Powell, Gareth S. and Byron Adams} } @article {4295, title = {Soil nematode abundance and functional group composition at a global scale}, journal = {Nature}, volume = {572}, year = {2019}, month = {08/2019}, abstract = {

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.

}, keywords = {LTER-MCM}, doi = {10.1038/s41586-019-1418-6}, url = {https://www.nature.com/articles/s41586-019-1418-6}, author = {van den Hoogen, Johan and Geisen, Stefan and Routh, Devin and Ferris, Howard and Traunspurger, Walter and Wardle, D and de Goede, Ron G. M. and Byron Adams and Ahmad, Wasim and Andriuzzi, Walter S. and Richard D. Bardgett and Bonkowski, Michael and Campos-Herrera, Raquel and Cares, Juvenil E. and Caruso, Tancredi and de Brito Caixeta, Larissa and Chen, Xiaoyun and Costa, Sofia R. and Creamer, Rachel and Mauro da Cunha Castro, Jos{\'e} and Dam, Marie and Djigal, Djibril and Escuer, Miguel and Griffiths, Bryan S. and Guti{\'e}rrez, Carmen and Hohberg, Karin and Kalinkina, Daria and Kardol, Paul and Kergunteuil, Alan and Korthals, Gerard and Krashevska, Valentyna and Kudrin, Alexey A. and Li, Qi and Liang, Wenju and Magilton, Matthew and Marais, Mariette and Mart{\'\i}n, Jos{\'e} Antonio Rodr{\'\i}guez and Matveeva, Elizaveta and Mayad, El Hassan and Mulder, Christian and Mullin, Peter and Neilson, Roy and Nguyen, T. A. Duong and Uffe N. Nielsen and Okada, Hiroaki and Rius, Juan Emilio Palomares and Pan, Kaiwen and Peneva, Vlada and Pellissier, Lo{\"\i}c and Carlos Pereira da Silva, Julio and Pitteloud, Camille and Powers, Thomas O. and Powers, Kirsten and Quist, Casper W. and Rasmann, Sergio and Moreno, Sara S{\'a}nchez and Scheu, Stefan and Set{\"a}l{\"a}, Heikki and Sushchuk, Anna and Tiunov, Alexei V. and Trap, Jean and van der Putten, W and Vesterg{\r a}rd, Mette and Villenave, Cecile and Waeyenberge, Lieven and Diana H. Wall and Wilschut, Rutger and Wright, Daniel G. and Yang, Jiue-in and Crowther, Thomas Ward} } @article {4156, title = {Aeolian material transport and its role in landscape connectivity in the McMurdo Dry Valleys, Antarctica}, journal = {Journal of Geophysical Research: Earth Surface}, volume = {123}, year = {2018}, month = {12/2018}, pages = {3323 - 3337}, abstract = {

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

}, keywords = {LTER-MCM}, doi = {10.1029/2017JF004589}, url = {https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2017JF004589}, author = {Melisa A. Diaz and Byron Adams and Kathleen A. Welch and Sue Welch and Opiyo, Stephen O. and Khan, Alia L. and Diane M. McKnight and Craig S Cary and W. Berry Lyons} } @article {4159, title = {BioTIME: A database of biodiversity time series for the Anthropocene}, journal = {Global Ecology and Biogeography}, volume = {27}, year = {2018}, month = {07/2018}, pages = {760-786}, abstract = {

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.

}, keywords = {LTER-MCM, biodiversity, global, spatial, species richness, temporal, turnover}, doi = {10.1111/geb.12729}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/geb.12729}, author = {Dornelas, Maria and Ant{\~a}o, Laura H. and Moyes, Faye and Bates, Amanda E. and Magurran, Anne E. and Adam, Du{\v s}an and Akhmetzhanova, Asem A. and Appeltans, Ward and Arcos, Jos{\'e} Manuel and Arnold, Haley and Ayyappan, Narayanan and Badihi, Gal and Baird, Andrew H. and Barbosa, Miguel and Barreto, Tiago Egydio and B{\"a}ssler, Claus and Bellgrove, Alecia and Belmaker, Jonathan and Benedetti-Cecchi, Lisandro and Bett, Brian J. and Bjorkman, Anne D. and B{\l}a{\.z}ewicz, Magdalena and Blowes, Shane A. and Bloch, Christopher P. and Bonebrake, Timothy C. and Boyd, Susan and Bradford, Matt and Brooks, Andrew J. and Brown, James H. and Bruelheide, Helge and Budy, Phaedra and Carvalho, Fernando and Casta{\~n}eda-Moya, Edward and Chen, Chaolun Allen and Chamblee, John F. and Chase, Tory J. and Siegwart Collier, Laura and Collinge, Sharon K. and Condit, Richard and Cooper, Elisabeth J. and Cornelissen, J. Hans C. and Cotano, Unai and Kyle Crow, Shannan and Damasceno, Gabriella and Davies, Claire H. and Davis, Robert A. and Day, Frank P. and Degraer, Steven and Doherty, Tim S. and Dunn, Timothy E. and Durigan, Giselda and Duffy, J. Emmett and Edelist, Dor and Edgar, Graham J. and Elahi, Robin and Elmendorf, Sarah C. and Enemar, Anders and Ernest, S. K. Morgan and Escribano, Rub{\'e}n and Estiarte, Marc and Evans, Brian S. and Fan, Tung-Yung and Turini Farah, Fabiano and Loureiro Fernandes, Luiz and Farneda, F{\'a}bio Z. and Fidelis, Alessandra and Fitt, Robert and Fosaa, Anna Maria and Daher Correa Franco, Geraldo Antonio and Frank, Grace E. and Fraser, William R. and Garc{\'\i}a, Hernando and Cazzolla Gatti, Roberto and Givan, Or and Gorgone-Barbosa, Elizabeth and Gould, William A. and Gries, Corinna and Grossman, Gary D. and Gutierr{\'e}z, Julio R. and Hale, Stephen and Harmon, Mark E. and Harte, John and Haskins, Gary and Henshaw, Donald L. and Hermanutz, Luise and Hidalgo, Pamela and Higuchi, Pedro and Hoey, Andrew and Van Hoey, Gert and Hofgaard, Annika and Holeck, Kristen and Hollister, Robert D. and Holmes, Richard and Hoogenboom, Mia and Hsieh, Chih-hao and Hubbell, Stephen P. and Huettmann, Falk and Huffard, Christine L. and Hurlbert, Allen H. and Macedo Ivanauskas, Nat{\'a}lia and Jan{\'\i}k, David and Jandt, Ute and Ja{\.z}d{\.z}ewska, Anna and Johannessen, Tore and Johnstone, Jill and Jones, Julia and Jones, Faith A. M. and Kang, Jungwon and Kartawijaya, Tasrif and Keeley, Erin C. and Kelt, Douglas A. and Kinnear, Rebecca and Klanderud, Kari and Knutsen, Halvor and Koenig, Christopher C. and Kortz, Alessandra R. and Kr{\'a}l, Kamil and Kuhnz, Linda A. and Kuo, Chao-Yang and Kushner, David J. and Laguionie-Marchais, Claire and Lancaster, Lesley T. and Min Lee, Cheol and Lefcheck, Jonathan S. and L{\'e}vesque, Esther and Lightfoot, David and Lloret, Francisco and Lloyd, John D. and L{\'o}pez-Baucells, Adri{\`a} and Louzao, Maite and Madin, Joshua S. and Magn{\'u}sson, Borg{\th}{\'o}r and Malamud, Shahar and Matthews, Iain and McFarland, Kent P. and McGill, Brian and Diane M. McKnight and McLarney, William O. and Meador, Jason and Meserve, Peter L. and Metcalfe, Daniel J. and Meyer, Christoph F. J. and Michelsen, Anders and Milchakova, Nataliya and Moens, Tom and Moland, Even and Moore, Jon and Mathias Moreira, Carolina and M{\"u}ller, J{\"o}rg and Murphy, Grace and Myers-Smith, Isla H. and Myster, Randall W. and Naumov, Andrew and Neat, Francis and Nelson, James A. and Paul Nelson, Michael and Newton, Stephen F. and Norden, Natalia and Oliver, Jeffrey C. and Olsen, Esben M. and Onipchenko, Vladimir G. and Pabis, Krzysztof and Pabst, Robert J. and Paquette, Alain and Pardede, Sinta and Paterson, David M. and P{\'e}lissier, Rapha{\"e}l and Pe{\~n}uelas, Josep and P{\'e}rez-Matus, Alejandro and Pizarro, Oscar and Pomati, Francesco and Post, Eric and Prins, Herbert H. T. and John C. Priscu and Provoost, Pieter and Prudic, Kathleen L. and Pulliainen, Erkki and Ramesh, B. R. and Mendivil Ramos, Olivia and Rassweiler, Andrew and Rebelo, Jose Eduardo and Reed, Daniel C. and Reich, Peter B. and Remillard, Suzanne M. and Richardson, Anthony J. and Richardson, J. Paul and van Rijn, Itai and Rocha, Ricardo and Rivera-Monroy, Victor H. and Rixen, Christian and Robinson, Kevin P. and Ribeiro Rodrigues, Ricardo and de Cerqueira Rossa-Feres, Denise and Rudstam, Lars and Ruhl, Henry and Ruz, Catalina S. and Sampaio, Erica M. and Rybicki, Nancy and Rypel, Andrew and Sal, Sofia and Salgado, Beatriz and Santos, Flavio A. M. and Savassi-Coutinho, Ana Paula and Scanga, Sara and Schmidt, Jochen and Schooley, Robert and Setiawan, Fakhrizal and Shao, Kwang-Tsao and Shaver, Gaius R. and Sherman, Sally and Sherry, Thomas W. and Sici{\'n}ski, Jacek and Sievers, Caya and da Silva, Ana Carolina and Rodrigues da Silva, Fernando and Silveira, Fabio L. and Slingsby, Jasper and Smart, Tracey and Snell, Sara J. and Soudzilovskaia, Nadejda A. and Souza, Gabriel B. G. and Maluf Souza, Flaviana and Castro Souza, Vin{\'\i}cius and Stallings, Christopher D. and Stanforth, Rowan and Stanley, Emily H. and Mauro Sterza, Jos{\'e} and Stevens, Maarten and Stuart-Smith, Rick and Rondon Suarez, Yzel and Supp, Sarah} } @phdthesis {4363, title = {Genomics and transcriptomics of Antarctic nematodes reveal drivers of life history evolution and genome evolution}, volume = {Ph.D.}, year = {2018}, school = {Brigham Young University}, type = {doctoral}, address = {Provo, UT}, abstract = {

Elemental stoichiometry defines a critical understanding of the relationship between\ nutrient availability and usage throughout different levels of the biological community. We\ found there is a link between available phosphorus (P), cellular phosphorus, and nematode development as postulated by the growth rate hypothesis (GRH). I predicted that in a P-poor environment, cellular RNA concentrations would be lower than they are in P-rich environment, and thus the 18srRNA expression level will have reduced. To most efficiently regulate the\ uptake of limited P, I predicted that nematodes in P-poor environments would decrease the number of copies of the 18s rRNA gene in their genome. I measured life history traits as well as rRNA gene expression and gene copy number. We found that elemental stoichiometry predicts evolutionary changes consistent with the Growth Rate Hypothesis. We sequenced and assembled a draft genome of P. murrayi. Although we expected to find genes responsible for stress tolerance, we hypothesized that in response to strong selection pressure associated with living in\ a simplified ecosystem, over time the genome of P. murrayi should have undergone significant decay (gene loss) relative to species in ecosystems structured more strongly by biotic interactions. We found significantly fewer genes in P. murrayi. To compare patterns of gene expression between two highly divergent Antarctic nematode species, we sequenced and assembled the transcriptomes of S. lindsayae and P. murrayi. Under laboratory conditions at 4\  ̊C, S. lindsayae had significantly lower rates of gene expression but expressed a significantly larger number of genes. We speculate that the differences in gene expression are correlated with life history traits (developmental rates) while the differences in the number of genes expressed can be explained\ by their different genetic systems (S. lindsayae is amphimictic, P. murrayi is parthenogenic) and the soil environments to which they are adapted. Since we previously showed that differences in available P content can influence the evolution of gene expression via gene copy number, and that this ultimately influences growth rate, we wondered how much of this response is driven by genetics versus how strongly these patterns are driven by temperature. To better understand this, we maintained wild type populations of P. murrayi in P-rich and P-poor conditions at 5\  ̊C, 10\  ̊C and 15 ̊C in the laboratory for over 40 generations and sequenced the transcriptomes prepared from each treatment group. We found that nutrient levels played an important role in gene expression when the temperature is optimal for P. murrayi culturing and that temperature is more important in gene expression when the available P is limited. This work underscores the utility of using principles of elemental stoichiometry coupled with genomic and transcriptomics research tools to make and test predictions about life history evolution. The results of my work also\ inform inferences about the ways in which nutrient availability also drives the organization of trophic interactions and ultimately ecosystems.

}, keywords = {LTER-MCM, Antarctic nematodes, Caenorhabditis elegans, genome evolution, growth rate hypothesis, Plectus murrayi, Scottnema lindsayae, transcriptome}, url = {https://search.proquest.com/docview/2081899003}, author = {Xue, Xia and Byron Adams} } @mastersthesis {4441, title = {Microbial and CO2 responses to water stresses show decreased productivity and diversity through time}, volume = {M.S.}, year = {2018}, month = {05/2018}, school = {Brigham Young University}, type = {masters}, address = {Provo, UT}, abstract = {

Some bacterial taxa when stimulated by water additions will break dormancy, grow, and become dominant members of the community and contribute significant pulses of\ CO2 associated with the rewetting event. These pulses of activity are associated with high levels of bacterial productivity in soils. (Aanderud et al. 2011) We examined the bacterial taxa that resuscitate and become metabolically active following two forms of water stress (soil drying- rewetting and freeze-thaw cycles) and we captured and measured the CO2 emanating from those soils. Specifically, We used target metagenomics, which uses a specific gene pool within bacteria that is associated with a function of an ecological process, in this case active (16S rRNA communities) bacteria and all bacteria (16S rRNA communities) during drying-rewetting and freeze-thaw cycles. We measured an array of community dynamics (i.e., evenness, richness, diversity, relative abundance of taxa, and network analyses between taxa) as dry soils are rewetted and as frozen soils thaw multiple times in three cold desert soils. Soils from all three locations exhibited some similar bacterial taxa and gene function but were large in part their own community derived from the evolutionary history of the continent in which they reside.

}, keywords = {LTER-MCM, dormancy, PiCRUST, turnover}, url = {https://scholarsarchive.byu.edu/etd/6830}, author = {Robinson, David M. and Aanderud, Zachary T.} } @article {4060, title = {Observed trends of soil fauna in the Antarctic Dry Valleys: early signs of shifts predicted under climate change}, journal = {Ecology}, volume = {99}, year = {2018}, month = {02/2018}, pages = {312 - 321}, abstract = {

Long-term observations of ecological communities are necessary for generating and testing predictions of ecosystem responses to climate change. We investigated temporal trends and spatial patterns of soil fauna along similar environmental gradients in three sites of the McMurdo Dry Valleys, Antarctica, spanning two distinct climatic phases: a decadal cool- ing trend from the early 1990s through the austral summer of February 2001, followed by a shift to the current trend of warming summers and more frequent discrete warming events. After February 2001, we observed a decline in the dominant species (the nematode Scottnema lindsayae) and increased abundance and expanded distribution of less common taxa (rotifers, tardigrades, and other nematode species). Such diverging responses have resulted in slightly greater evenness and spatial homogeneity of taxa. However, total abundance of soil fauna appears to be declining, as positive trends of the less common species so far have not compen- sated for the declining numbers of the dominant species. Interannual variation in the propor- tion of juveniles in the dominant species was consistent across sites, whereas trends in abundance varied more. Structural equation modeling supports the hypothesis that the observed biological trends arose from dissimilar responses by dominant and less common spe- cies to pulses of water availability resulting from enhanced ice melt. No direct effects of mean summer temperature were found, but there is evidence of indirect effects via its weak but signif- icant positive relationship with soil moisture. Our findings show that combining an under- standing of species responses to environmental change with long-term observations in the field can provide a context for validating and refining predictions of ecological trends in the abun- dance and diversity of soil fauna.\ 

}, keywords = {LTER-MCM}, doi = {10.1002/ecy.2090}, url = {http://doi.wiley.com/10.1002/ecy.2090/full}, author = {Andriuzzi, Walter S. and Byron Adams and John E. Barrett and Ross A. Virginia and Diana H. Wall} } @article {4155, title = {Photoecology of the Antarctic cyanobacterium Leptolyngbya sp. BC1307 brought to light through community analysis, comparative genomics and in vitro photophysiology}, journal = {Molecular Ecology}, volume = {27}, year = {2018}, month = {11/2018}, pages = {5279 - 5293}, abstract = {

Cyanobacteria are important photoautotrophs in extreme environments such as the McMurdo Dry Valleys, Antarctica. Terrestrial Antarctic cyanobacteria experience constant darkness during the winter and constant light during the summer which influences the ability of these organisms to fix carbon over the course of an annual cycle. Here, we present a unique approach combining community structure, genomic and photophysiological analyses to understand adaptation to Antarctic light regimes in the cyanobacterium Leptolyngbya sp. BC1307. We show that Leptolyngbya sp. BC1307 belongs to a clade of cyanobacteria that inhabits near-surface environments in the McMurdo Dry Valleys. Genomic analyses reveal that, unlike close relatives, Leptolyngbya sp. BC1307 lacks the genes necessary for production of the pigment phycoerythrin and is incapable of complimentary chromatic acclimation, while containing several genes responsible for known photoprotective pigments. Photophysiology experiments confirmed Leptolyngbya sp. BC1307 to be tolerant of short-term exposure to high levels of photosynthetically active radiation, while sustained exposure reduced its capacity for photoprotection. As such, Leptolyngbya sp. BC1307 likely exploits low-light microenvironments within cyanobacterial mats in the McMurdo Dry Valleys.

}, keywords = {LTER-MCM, Antarctica, cyanobacteria, genomics, photoecology, photophysiology}, doi = {10.1111/mec.14953}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/mec.14953}, author = {Chrismas, Nathan A. M. and Williamson, Christopher J. and Yallop, Marian L. and Alexandre M. Anesio and S{\'a}nchez-Baracaldo, Patricia} } @article {4080, title = {Soil biological responses to C, N and P fertilization in a polar desert of Antarctica}, journal = {Soil Biology and Biochemistry}, volume = {122}, year = {2018}, month = {07/2018}, chapter = {7}, abstract = {

In the polar desert ecosystem of the McMurdo Dry Valleys of Antarctica, biology is constrained by available liquid water, low temperatures, as well as the availability of organic matter and nutrient elements. These soil ecosystems are climate-sensitive, where projected future warming may have profound effects on biological communities and biogeochemical cycling. Warmer temperatures will mobilize meltwater from permafrost and glaciers, may increase precipitation and may be accompanied by pulses of nutrient availability. Enhanced water and nutrient availability have the potential to greatly influence desert soil biology and ecosystem processes. The objectives of this 5-year study were to determine which nutrient elements (C, N, P) are most limiting to dry valley soil communities and whether landscape history (i.e.,\ in situ\ soil type and stoichiometry) influences soil community response to nutrient additions. After 3 years of no noticeable response, soil CO2\ flux was significantly higher under addition of C+ N than the other treatments, regardless of\ in situ\ soil stoichiometry, but microbial biomass and invertebrate abundance were variable and not influenced in the same manner. A stable isotope incubation suggests that fertilization increases C and N mineralization from organic matter via stimulating microbial activity, with loss of both the applied treatments as well\ in situ\ C and N. However, these responses are relatively short-lived, suggesting long-term impacts on C and N cycling would only occur if meltwater and nutrient pulses are sustained over time, a scenario that is increasingly likely for the dry valleys.

}, keywords = {LTER-MCM}, issn = {00380717}, doi = {10.1016/j.soilbio.2018.03.025}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0038071718301081}, author = {Ball, Becky and Byron Adams and John E. Barrett and Diana H. Wall and Ross A. Virginia} } @article {4058, title = {Soil Moisture Controls the Thermal Habitat of Active Layer Soils in the McMurdo Dry Valleys, Antarctica}, journal = {Journal of Geophysical Research: Biogeosciences}, volume = {123}, year = {2018}, month = {01/2018}, chapter = {46-59}, abstract = {

Antarctic soil ecosystems are strongly controlled by abiotic habitat variables. Regional climate change in the McMurdo Dry Valleys is expected to cause warming over the next century, leading to an increase in frequency of freeze-thaw cycling in the soil habitat. Previous studies show that physiological stress associated with freeze-thaw cycling adversely affects invertebrate populations by decreasing abundance and positively selecting for larger body sizes. However, it remains unclear whether or not climate warming will indeed enhance the frequency of annual freeze-thaw cycling and associated physiological stresses. This research quantifies the frequency, rate, and spatial heterogeneity of active layer freezing to better understand how regional climate change may affect active layer soil thermodynamics, and, in turn, affect soil macroinvertebrate communities. Shallow active layer temperature, specific conductance, and soil moisture were observed along natural wetness gradients. Field observations show that the frequency and rate of freeze events are nonlinearly related to freezable soil moisture (θf). Over a 2 year period, soils at θf \< 0.080 m3/m3 experienced between 15 and 35 freeze events and froze rapidly compared to soils with θf \> 0.080 m3/m3, which experienced between 2 and 6 freeze events and froze more gradually. A numerical soil thermodynamic model is able to simulate observed freezing rates across a range of θf, reinforcing a well-known causal relationship between soil moisture and active layer freezing dynamics. Findings show that slight increases in soil moisture can potentially offset the effect of climate warming on exacerbating soil freeze-thaw cycling.

}, keywords = {LTER-MCM}, doi = {10.1002/2017JG004018}, url = {https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017JG004018}, author = {Wlostowski, Adam and Michael N. Gooseff and Byron Adams} } @article {4107, title = {Spatial and temporal patterns of microbial mats and associated invertebrates along an Antarctic stream}, journal = {Polar Biology}, volume = {41}, year = {2018}, month = {10/2018}, pages = {1911{\textendash}1921}, abstract = {

Microbial biofilms are biological hotspots in many alpine and polar ecosystems, but the controls on and functional significance of their fauna are little known. We studied cyanobacterial mats and the underlying sediment in a glacial meltwater stream in the McMurdo Dry Valleys, Antarctica. We investigated mat biomass (total and phototrophic), diatoms, and micro-meiofauna (nematodes, rotifers, and tardigrades) at nine sites along a 1670 m stream reach in a cold, low-flow growing season, and in a warmer growing season in which peak flows (above 100 L s\−1) scoured the mats. Diatom and invertebrate communities were not related, but mat biomass in the low-flow year was negatively related to nematode abundance, including that of the omnivore\ Eudorylaimus. In the high-flow year that followed, invertebrate abundance was reduced in the mats, diatom community structure was altered, and mat biomass was higher. The difference in invertebrate abundance between years was greater in mats in upstream reaches, where the greatest increases in flow velocity may have occurred, and was negligible in mats in downstream reaches as well as in the sediment beneath the mats. Integrating our results with previous findings, we generate two predictive hypotheses to be tested in glacial meltwater streams: (1) under peak flows invertebrates decline in the microbial mats, while (2) the sediment beneath the mats is a refuge from the flow disturbance. Our results also suggest that, under stable flow conditions, microinvertebrate grazers could exert top-down control on microbial mat biomass.

}, keywords = {LTER-MCM, diatoms, Disturbance, Dry valleys, Epilithon, Microfauna, Stream flow}, doi = {10.1007/s00300-018-2331-4}, url = {http://link.springer.com/10.1007/s00300-018-2331-4}, author = {Andriuzzi, Walter S. and Lee F. Stanish and Breana L. Simmons and Chris Jaros and Byron Adams and Diana H. Wall and Diane M. McKnight} } @article {4059, title = {Stable C and N isotope ratios reveal soil food web structure and identify the nematode Eudorylaimus antarcticus as an omnivore{\textendash}predator in~Taylor Valley, Antarctica}, journal = {Polar Biology}, volume = {41}, year = {2018}, month = {05/2018}, pages = {1013{\textendash}1018}, abstract = {

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

}, keywords = {LTER-MCM}, doi = {10.1007/s00300-017-2243-8}, url = {http://link.springer.com/10.1007/s00300-017-2243-8}, author = {Shaw, E. Ashley and Byron Adams and John E. Barrett and W. Berry Lyons and Ross A. Virginia and Diana H. Wall} } @article {4139, title = {Stoichiometric Shifts in Soil C:N:P Promote Bacterial Taxa Dominance, Maintain Biodiversity, and Deconstruct Community Assemblages}, journal = {Frontiers in Microbiology}, volume = {9}, year = {2018}, month = {07/2018}, abstract = {

Imbalances in C:N:P supply ratios may cause bacterial resource limitations and constrain biogeochemical processes, but the importance of shifts in soil stoichiometry are complicated by the nearly limitless interactions between an immensely rich species pool and a multiple chemical resource forms. To more clearly identify the impact of soil C:N:P on bacteria, we evaluated the cumulative effects of single and coupled long-term nutrient additions (i.e., C as mannitol, N as equal concentrations NH4 + and NO3 \− , and P as Na3PO4) and water on communities in an Antarctic polar desert, Taylor Valley. Untreated soils possessed relatively low bacterial diversity, simplified organic C sources due to the absence of plants, limited inorganic N, and excess soil P potentially attenuating links between C:N:P. After 6 years of adding resources, an alleviation of C and N colimitation allowed one rare Micrococcaceae, an Arthrobacter species, to dominate, comprising 47\% of the total community abundance and elevating soil respiration by 136\% relative to untreated soils. The addition of N alone reduced C:N ratios, elevated bacterial richness and diversity, and allowed rare taxa relying on ammonium and nitrite for metabolism to become more abundant [e.g., nitrite oxidizing Nitrospira species (Nitrosomonadaceae), denitrifiers utilizing nitrite (Gemmatimonadaceae) and members of Rhodobacteraceae with a high affinity for ammonium]. Based on community co-occurrence networks, lower C:P ratios in soils following P and CP additions created more diffuse and less connected communities by disrupting 73\% of species interactions and selecting for taxa potentially exploiting abundant P. Unlike amended nutrients, water additions alone elicited no lasting impact on communities. Our results suggest that as soils become nutrient rich a wide array of outcomes are possible from species dominance and the deconstruction of species interconnectedness to the maintenance of biodiversity.

}, keywords = {LTER-MCM, ecological stoichiometry, Lake Fryxell Basin, McMurdo Dry Valleys, network community modeling, nutrient colimitation, Solirubrobacteriaceae}, doi = {10.3389/fmicb.2018.01401}, url = {https://www.frontiersin.org/article/10.3389/fmicb.2018.01401/full}, author = {Aanderud, Zachary T. and Saurey, Sabrina D. and Ball, Becky and Diana H. Wall and John E. Barrett and Muscarella, Mario E. and Griffin, Natasha A. and Ross A. Virginia and Byron Adams} } @article {4112, title = {A communal catalogue reveals Earth{\textquoteright}s multiscale microbial diversity}, journal = {Nature}, volume = {551}, year = {2017}, month = {11/2017}, chapter = {457}, abstract = {

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.

}, keywords = {LTER-MCM}, doi = {10.1038/nature24621}, url = {https://www.nature.com/articles/nature24621}, author = {Thompson, Luke R. and Sanders, Jon G. and McDonald, Daniel and Amir, Amnon and Ladau, Joshua and Locey, Kenneth J. and Prill, Robert J. and Tripathi, Anupriya and Gibbons, Sean M. and Ackermann, Gail and Navas-Molina, Jose A. and Janssen, Stefan and Kopylova, Evguenia and V{\'a}zquez-Baeza, Yoshiki and Antonio Gonz{\'a}lez and Morton, James T. and Mirarab, Siavash and Zech Xu, Zhenjiang and Jiang, Lingjing and Haroon, Mohamed F. and Kanbar, Jad and Zhu, Qiyun and Jin Song, Se and Kosciolek, Tomasz and Bokulich, Nicholas A. and Lefler, Joshua and Brislawn, Colin J. and Humphrey, Gregory and Owens, Sarah M. and Hampton-Marcell, Jarrad and Berg-Lyons, Donna and McKenzie, Valerie and Noah Fierer and Fuhrman, Jed A. and Clauset, Aaron and Stevens, Rick L. and Shade, Ashley and Pollard, Katherine S. and Goodwin, Kelly D. and Jansson, Janet K. and Gilbert, Jack A. and Knight, Rob and The Earth Microbiome Project Consortium} } @article {4022, title = {Decadal ecosystem response to an anomalous melt season in a polar desert in Antarctica}, journal = {Nature Ecology \& Evolution}, volume = {1}, year = {2017}, month = {09/2017}, pages = {1334-1338}, keywords = {LTER-MCM}, doi = {10.1038/s41559-017-0253-0}, url = {https://www.nature.com/articles/s41559-017-0253-0}, author = {Michael N. Gooseff and John E. Barrett and Byron Adams and Peter T. Doran and Andrew G Fountain and W. Berry Lyons and Diane M. McKnight and John C. Priscu and Eric R. Sokol and Cristina D. Takacs-Vesbach and Martijn L. Vandegehuchte and Ross A. Virginia and Diana H. Wall} } @article {4024, title = {Decoupled responses of soil bacteria and their invertebrate consumer to warming, but not freeze-thaw cycles, in the Antarctic Dry Valleys}, journal = {Ecology Letters}, volume = {20}, year = {2017}, month = {10/2017}, pages = {1242-1249}, abstract = {

Altered temperature profiles resulting in increased warming and freeze\–thaw cycle (FTC) frequency pose great ecological challenges to organisms in alpine and polar ecosystems. We performed a laboratory microcosm experiment to investigate how temperature variability affects soil bacterial cell numbers, and abundance and traits of soil microfauna (the microbivorous nematode Scottnema lindsayae) from McMurdo Dry Valleys, Antarctica. FTCs and constant freezing shifted nematode body size distribution towards large individuals, driven by higher mortality among smaller individuals. FTCs reduced both bacterial and nematode abundance, but bacterial cell numbers also declined under warming, demonstrating decoupled consumer\–prey responses. We predict that higher occurrence of FTCs in cold ecosystems will select for large body size within soil microinvertebrates and overall reduce their abundance. In contrast, warm temperatures without FTCs could lead to divergent responses in soil bacteria and their microinvertebrate consumers, potentially affecting energy and nutrient transfer rates in soil food webs of cold ecosystems.

}, keywords = {LTER-MCM}, doi = {10.1111/ele.12819}, url = {http://onlinelibrary.wiley.com/doi/10.1111/ele.12819/full}, author = {Matthew Knox and Andriuzzi, Walter S. and Heather N. Buelow and Cristina D. Takacs-Vesbach and Byron Adams and Diana H. Wall} } @article {4002, title = {Dissolved black carbon in the global cryosphere: Concentrations and chemical signatures}, journal = {Geophysical Research Letters}, volume = {44}, year = {2017}, month = {06/2017}, pages = {6226-6234}, abstract = {

Black carbon (BC) is derived from the incomplete combustion of biomass and fossil fuels and can enhance glacial recession when deposited on snow and ice surfaces. Here we explore the influence of environmental conditions and the proximity to anthropogenic sources on the concentration and composition of dissolved black carbon (DBC), as measured by benzenepolycaroxylic acid (BPCA) markers, across snow, lakes, and streams from the global cryosphere. Data are presented from Antarctica, the Arctic, and high alpine regions of the Himalayas, Rockies, Andes, and Alps. DBC concentrations spanned from 0.62 μg/L to 170 μg/L. The median and (2.5, 97.5) quantiles in the pristine samples were 1.8 μg/L (0.62, 12), and nonpristine samples were 21 μg/L (1.6, 170). DBC is susceptible to photodegradation when exposed to solar radiation. This process leads to a less condensed BPCA signature. In general, DBC across the data set was composed of less polycondensed DBC. However, DBC from the Greenland Ice Sheet (GRIS) had a highly condensed BPCA molecular signature. This could be due to recent deposition of BC from Canadian wildfires. Variation in DBC appears to be driven by a combination of photochemical processing and the source combustion conditions under which the DBC was formed. Overall, DBC was found to persist across the global cryosphere in both pristine and nonpristine snow and surface waters. The high concentration of DBC measured in supraglacial melt on the GRIS suggests that DBC can be mobilized across ice surfaces. This is significant because these processes may jointly exacerbate surface albedo reduction in the cryosphere.\ 

}, keywords = {LTER-MCM}, doi = {10.1002/2017GL073485}, url = {http://doi.wiley.com/10.1002/2017GL073485}, author = {Khan, Alia L. and Wagner, Sasha and Jaff{\'e}, Rudolf and Xian, Peng and Williams, Mark and Armstrong, Richard and Diane M. McKnight} } @article {3713, title = {Aerobiology Over Antarctica {\textendash} A New Initiative for Atmospheric Ecology}, journal = {Frontiers in Microbiology}, volume = {776796194610314927235011365134445142846479110123936574}, year = {2016}, month = {02/2016}, keywords = {LTER-MCM}, doi = {10.3389/fmicb.2016.00016}, url = {http://journal.frontiersin.org/Article/10.3389/fmicb.2016.00016/abstract}, author = {Pearce, David A. and Alekhina, Irina A. and Terauds, Aleks and Wilmotte, Annick and Quesada, Antonio and Edwards, Arwyn and Dommergue, Aurelien and Sattler, Birgit and Byron Adams and Magalhaes, Catarina and Chu, Wan-Loy and Lau, Maggie C. Y. and Craig S Cary and Smith, David J. and Diana H. Wall and Eguren, Gabriela and Matcher, Gwynneth and Bradley, James A. and de Vera, Jean-Pierre and Elster, Josef and Hughes, Kevin A. and Cuthbertson, Lewis and Benning, Liane G. and Gunde-Cimerman, Nina and Convey, Peter and Hong, Soon Gyu and Pointing, Steve B. and Pellizari, Vivian H. and Vincent, Warwick F.} } @article {3717, title = {Biogeochemistry and microbial diversity in the marine cavity beneath the McMurdo Ice Shelf, Antarctica}, journal = {Limnology and Oceanography}, volume = {61}, year = {2016}, month = {11/2015}, pages = {572 - 586}, keywords = {LTER-MCM}, doi = {10.1002/lno.v61.210.1002/lno.10234}, url = {http://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.10234}, author = {Trista J. Vick-Majors and Achberger, Amanda and Santib{\'a}{\~n}ez, Pamela and John E. Dore and Hodson, Timothy and Alexander B. Michaud and Brent C. Christner and Jill Ai, Jill. Mikucki and Skidmore, Mark L. and Powell, Ross and Adkins, W. Peyton and Barbante, Carlo and Mitchell, Andrew and Scherer, Reed and John C. Priscu} } @article {4014, title = {Genetic diversity among populations of Antarctic springtails (Collembola) within the Mackay Glacier ecotone 1}, journal = {Genome}, volume = {59}, year = {2016}, month = {Jan-09-2016}, pages = {762 - 770}, keywords = {LTER-MCM}, issn = {0831-2796}, doi = {10.1139/gen-2015-0194}, url = {http://www.nrcresearchpress.com/doi/10.1139/gen-2015-0194}, author = {Clare R. Beet and Hogg, Ian D. and Gemma E. Collins and Cowan, Don A. and Diana H. Wall and Byron Adams and John-James Wilson} } @article {4015, title = {High levels of intraspecific genetic divergences revealed for Antarctic springtails: evidence for small-scale isolation during Pleistocene glaciation}, journal = {Biological Journal of the Linnean Society}, volume = {119}, year = {2016}, month = {Jan-09-2016}, pages = {166 - 178}, keywords = {LTER-MCM}, doi = {10.1111/bij.12796}, url = {https://academic.oup.com/biolinnean/article-lookup/doi/10.1111/bij.12796https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111\%2Fbij.12796}, author = {Bennett, Kristi R. and Hogg, Ian D. and Byron Adams and Hebert, Paul D. N.} } @article {3707, title = {High-resolution ground-penetrating radar profiles of perennial lake ice in the McMurdo Dry Valleys, Antarctica: Horizon attributes, unconformities, and subbottom penetration}, journal = {GEOPHYSICS}, volume = {81}, year = {2016}, month = {01/2016}, pages = {WA13 - WA20}, keywords = {LTER-MCM}, issn = {0016-8033}, doi = {10.1190/geo2015-0159.1}, url = {http://library.seg.org/doi/10.1190/geo2015-0159.1}, author = {Hilary A. Dugan and Arcone, Steven A. and Maciek K. Obryk and Peter T. Doran} } @article {4102, title = {The Impact of a Large-Scale Climate Event on Antarctic Ecosystem Processes}, journal = {BioScience}, volume = {66}, year = {2016}, month = {10/2016}, pages = {848 - 863}, abstract = {

Extreme climate and weather events, such as a drought, hurricanes, or ice storms, can strongly imprint ecosystem processing and may alter ecosystem structure. Ecosystems in extreme environments are particularly vulnerable because of their adaptation to severe limitations in energy, water, or nutrients. The vulnerability can be expressed as a relatively long-lasting ecosystem response to a small or brief change in environmental conditions. Such an event occurred in Antarctica and affected two vastly different ecosystems: a marine-dominated coastal system and a terrestrial polar desert. Both sites experienced winds that warmed air temperatures above the 0\°C threshold, resulting in extensive snow and ice melt and triggering a series of cascading effects through the ecosystems that are continuing to play out more than a decade later. This highlights the sensitivity of Antarctic ecosystems to warming events, which should occur more frequently in the future with global climate warming.

}, keywords = {LTER-MCM}, issn = {0006-3568}, doi = {10.1093/biosci/biw110}, url = {http://academic.oup.com/bioscience/article-pdf/66/10/848/7510601/biw110.pdf}, author = {Andrew G Fountain and Saba, Grace and Byron Adams and Peter T. Doran and Fraser, William and Michael N. Gooseff and Maciek K. Obryk and John C. Priscu and Sharon E. Stammerjohn and Ross A. Virginia} } @article {4025, title = {Impact of diurnal freeze{\textendash}thaw cycles on the soil nematode Scottnema lindsayae in Taylor Valley, Antarctica}, journal = {Polar Biology}, volume = {39}, year = {2016}, month = {04/2016}, pages = {583 - 592}, keywords = {LTER-MCM}, issn = {0722-4060}, doi = {10.1007/s00300-015-1809-6}, url = {https://link.springer.com/article/10.1007/s00300-015-1809-6}, author = {Matthew Knox and Diana H. Wall and Ross A. Virginia and Martijn L. Vandegehuchte and Inigo San Gil and Byron Adams} } @article {4013, title = {Microbial Community Structure of Subglacial Lake Whillans, West Antarctica}, journal = {Frontiers in Microbiology}, volume = {7}, year = {2016}, month = {Oct-09-2017}, keywords = {LTER-MCM}, doi = {10.3389/fmicb.2016.01457}, url = {http://journal.frontiersin.org/Article/10.3389/fmicb.2016.01457/abstract}, author = {Achberger, Amanda and Brent C. Christner and Alexander B. Michaud and John C. Priscu and Skidmore, Mark L. and Trista J. Vick-Majors} } @mastersthesis {4081, title = {Modeling Surface Photosynthetic Active Radiation in Taylor Valley, McMurdo Dry Valleys, Antarctica}, volume = {M.S.}, year = {2016}, school = {University of Illinois at Chicago}, type = {masters}, address = {Chicago, IL}, abstract = {

Understanding primary productivity is a core research area of the National Science Foundation\’s Long-Term Ecological Research Network. This study maps surface Photosynthetically Active Radiation (PAR) using long term data collected by a meteorological network in the McMurdo Dry Valleys. Four stations with ~20 years of records were used to correct T-sPAR, a topographic surface PAR model. Maximum expected daily surface PAR at meteorological stations was calculated for Taylor Valley, through statistical analysis of location records using a local regression model that included 84\% of all observations. Expected values represent daily surface PAR under cloudless conditions. Daily measured and expected PAR was used to model cloud coverage at each location, corroborating that overcast conditions are positively correlated with proximity to the ocean. Ground-truth data collected for TaylorValley\’s major lakes\ during the 2015/2016 field season were used to validate T-sPAR estimates. The final model approximates total seasonal surface PAR for the Taylor Valley basin. Bi- monthly maps estimate total surface PAR by lake to assist in future sampling site selection. Finally, a user interface was developed to estimate total daily surface PAR by coordinate or surface based on a user input date.

}, keywords = {LTER-MCM, digital elevation model (DEM), geographical information system (GIS), ice-covered lakes, meteorological data, R model}, url = {http://indigo.uic.edu/handle/10027/21180}, author = {Acosta, Dimitri R.}, editor = {Berkelhammer, Max} } @article {4033, title = {Physiological Ecology of Microorganisms in Subglacial Lake Whillans}, journal = {Frontiers in Microbiology}, volume = {7}, year = {2016}, month = {Mar-10-2018}, keywords = {LTER-MCM}, doi = {10.3389/fmicb.2016.01705}, url = {http://journal.frontiersin.org/article/10.3389/fmicb.2016.01705/fullhttp://journal.frontiersin.org/article/10.3389/fmicb.2016.01705/full}, author = {Trista J. Vick-Majors and Mitchell, Andrew and Achberger, Amanda and Brent C. Christner and John E. Dore and Alexander B. Michaud and Jill A. Mikucki and Purcell, Alicia M. and Skidmore, Mark L. and John C. Priscu} } @article {3254, title = {Cyanobacterial diversity in benthic mats of the McMurdo Dry Valley lakes, Antarctica}, journal = {Polar Biology}, volume = {38}, year = {2015}, month = {01/2015}, pages = {1097 - 1110}, abstract = {
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.
}, keywords = {LTER-MCM}, issn = {0722-4060}, doi = {10.1007/s00300-015-1669-0}, url = {http://link.springer.com/10.1007/s00300-015-1669-0http://link.springer.com/content/pdf/10.1007/s00300-015-1669-0}, author = {Zhang, L. and Jungblut, Anne D. and Ian Hawes and Dale T. Andersen and Sumner, Dawn Y. and Mackey, Tyler J.} } @article {3012, title = {Deep groundwater and potential subsurface habitats beneath an Antarctic dry valley}, journal = {Nature Communications}, volume = {6}, year = {2015}, month = {Apr-04-2017}, pages = {6831}, abstract = {The occurrence of groundwater in Antarctica, particularly in the ice-free regions and along the coastal margins is poorly understood. Here we use an airborne transient electromagnetic (AEM) sensor to produce extensive imagery of resistivity beneath Taylor Valley. Regional-scale zones of low subsurface resistivity were detected that are inconsistent with the high resistivity of glacier ice or dry permafrost in this region. We interpret these results as an indication that liquid, with sufficiently high solute content, exists at temperatures well below freezing and considered within the range suitable for microbial life. These inferred brines are widespread within permafrost and extend below glaciers and lakes. One system emanates from below Taylor Glacier into Lake Bonney and a second system connects the ocean with the eastern 18 km of the valley. A connection between these two basins was not detected to the depth limitation of the AEM survey (~350 m).}, keywords = {LTER-MCM}, doi = {10.1038/ncomms7831}, url = {http://www.nature.com/doifinder/10.1038/ncomms7831}, author = {Jill A. Mikucki and Auken, E. and Tulaczyk, S and Ross A. Virginia and Schamper, C. and S{\o}rensen, K. I. and Peter T. Doran and Hilary A. Dugan and Foley, N.} } @article {3716, title = {Mitochondrial DNA analyses reveal widespread tardigrade diversity in Antarctica}, journal = {Invertebrate Systematics}, volume = {29}, year = {2015}, month = {12/2015}, pages = {578}, keywords = {LTER-MCM}, issn = {1445-5226}, doi = {10.1071/IS14019}, url = {http://www.publish.csiro.au/?paper=IS14019}, author = {Velasco-Castrillon, Alejandro and McInnes, Sandra J. and Schultz, Mark B. and Arroniz-Crespo, Maria and D{\textquoteright}Haese, Cyrille A. and Gibson, John A. E. and Byron Adams and Page, Timothy J. and Austin, Andrew D. and Cooper, Steven J. B. and Stevens, Mark I.} } @article {3222, title = {A roadmap for Antarctic and Southern Ocean science for the next two decades and beyond}, journal = {Antarctic Science}, volume = {27}, year = {2015}, month = {Jan-02-2015}, pages = {3 - 18}, abstract = {

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

}, keywords = {LTER-MCM}, issn = {0954-1020}, doi = {10.1017/S0954102014000674}, url = {http://www.journals.cambridge.org/abstract_S0954102014000674}, author = {Kennicutt, M.C. and Steven L. Chown and Cassano, J.J. and Liggett, D. and Lloyd S. Peck and Massom, R. and Rintoul, S.R. and Storey, J. and Vaughan, D.G. and Wilson, T.J. and Allison, I. and Ayton, J. and Badhe, R. and Baeseman, J. and Barrett, P.J. and Elanor R. Bell and Bertler, N. and Bo, S. and Brandt, A. and David Bromwich and Craig S Cary and Clark, M.S. and Peter Convey and Costa, E.S. and Cowan, D. and Deconto, R. and Dunbar, R. and Elfring, C. and Escutia, C. and Francis, J. and Fricker, H.A. and Fukuchi, M. and Gilbert, N. and Gutt, J. and Havermans, C. and Hik, D. and Hosie, G. and Jones, C. and Kim, Y.D. and Le Maho, Y. and Lee, S.H. and Leppe, M. and Leitchenkov, G. and Li, X. and Lipenkov, V. and Lochte, K. and L{\'o}pez-Mart{\'\i}nez, J. and {\"u}decke, C. and W. Berry Lyons and Marenssi, S. and Miller, H. and Morozova, P. and Naish, T. and Nayak, S. and Ravindra, R. and Retamales, J. and Ricci, C.A. and Rogan-Finnemore, M. and Ropert-Coudert, Y. and Samah, A.A. and Sanson, L. and Scambos, T. and I.R. Schloss and Shiraishi, K. and Siegert, M.J. and Sim{\~o}es, J.C. and Storey, B. and Sparrow, M.D. and Diana H. Wall and Walsh, J.C. and Wilson, G. and Winther, J.G. and J.C. Xavier and Yang, H. and Sutherland, W.J.} } @article {1063, title = {Sediment transport dynamics on an ice-covered lake: The {\textquotedblleft}floating{\textquotedblright} boulders of Lake Hoare, Antarctica}, journal = {Antartic Science}, volume = {firstview}, year = {2015}, month = {04/2015}, pages = {1-12}, chapter = {1}, abstract = {

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.

}, keywords = {LTER-MCM}, issn = {1365-2079}, doi = {10.1017/S0954102014000558}, url = {http://dx.doi.org/10.1017/S0954102014000558}, author = {P. P. Allen and R. Hewitt and Maciek K. Obryk and Peter T. Doran} } @article {1054, title = {Bacterial community composition of divergent soil habitats from a polar desert.}, journal = {FEMS Microbiology Ecology}, volume = {89}, year = {2014}, month = {08/2014}, pages = {490-494}, type = {Short Communication}, chapter = {490}, abstract = {Edaphic factors such as pH, organic matter, and salinity are often the most significant drivers of diversity patterns in soil bacterial communities. Desert ecosystems in particular are model locations for examining such relationships as food web complexity is low and the soil environment is biogeochemically heterogeneous. Here, we present the findings from a 16S rRNA gene sequencing approach used to observe the differences in diversity and community composition among three divergent soil habitats of the McMurdo Dry Valleys, Antarctica. Results show that alpha diversity is significantly lowered in high pH soils, which contain higher proportions of the phyla Acidobacteria and Actinobacteria, while mesic soils with higher soil organic carbon (and ammonium) content contain high proportions of Nitrospira, a nitrite-oxidizing bacteria. Taxonomic community resolution also had a significant impact on our conclusions, as pH was the primary predictor of phylum-level diversity, while moisture was the most significant predictor of diversity at the genus level. Predictive power also increased with increasing taxonomic resolution, suggesting a potential increase in nic}, keywords = {LTER-MCM}, doi = {10.1111/1574-6941.12306}, author = {Kevin M. Geyer and Adam E. Altrichter and Cristina D. Takacs-Vesbach and Michael N. Gooseff and John E. Barrett} } @article {1056, title = {Ciliate diversity, community structure and novel taxa in lakes of the McMurdo Dry Valleys, Antarctica}, journal = {Biological Bulleting}, volume = {227}, year = {2014}, month = {10/2014}, pages = {175-190}, chapter = {175}, abstract = {We report an in-depth survey of next-generation DNA sequencing of ciliate diversity and community structure in two permanently ice-covered McMurdo Dry Valley lakes during the austral summer and autumn (November 2007 and March 2008). We tested hypotheses on the relationship between species richness and environmental conditions including environmental extremes, nutrient status, and day length. On the basis of the unique environment that exists in these high-latitude lakes, we expected that novel taxa would be present. Alpha diversity analyses showed that extreme conditions-that is, high salinity, low oxygen, and extreme changes in day length-did not impact ciliate richness; however, ciliate richness was 30\% higher in samples with higher dissolved organic matter. Beta diversity analyses revealed that ciliate communities clustered by dissolved oxygen, depth, and salinity, but not by season (i.e., day length). The permutational analysis of variance test indicated that depth, dissolved oxygen, and salinity had significant influences on the ciliate community for the abundance matrices of resampled data, while lake and season were not significant. This result suggests that the vertical trends in dissolved oxygen concentration and salinity may play a critical role in structuring ciliate communities. A PCR-based strategy capitalizing on divergent eukaryotic V9 hypervariable region ribosomal RNA gene targets unveiled two new genera in these lakes. A novel taxon belonging to an unknown class most closely related to Cryptocaryon irritans was also inferred from separate gene phylogenies.}, keywords = {LTER-MCM}, author = {Yuan, Xu and Trista J. Vick-Majors and Rachael M. Morgan-Kiss and John C. Priscu and Linda A. Amaral-Zettler} } @article {3218, title = {Ecological Biogeography of the Terrestrial Nematodes~of Victoria Land, Antarctica}, journal = {ZooKeys}, volume = {419}, year = {2014}, month = {06/2015}, pages = {29 - 71}, keywords = {LTER-MCM}, issn = {1313-2989}, doi = {10.3897/zookeys.419.7180}, url = {http://zookeys.pensoft.net/articles.php?id=3899}, author = {Byron Adams and Diana H. Wall and Ross A. Virginia and Broos, Emma and Matthew Knox} } @article {3533, title = {Global-scale patterns of assemblage structure of soil nematodes in relation to climate and ecosystem properties}, journal = {Global Ecology and Biogeography}, volume = {23}, year = {2014}, month = {01/2014}, pages = {968 - 978}, keywords = {LTER-MCM}, doi = {10.1111/geb.2014.23.issue-910.1111/geb.12177}, url = {http://doi.wiley.com/10.1111/geb.12177}, author = {Uffe N. Nielsen and Edward Ayres and Diana H. Wall and Li, Grace and Richard D. Bardgett and Wu, Tiehang and James R. Garey} } @article {1085, title = {Modular community structure suggests metabolic plasticity during the transition to polar night in ice-covered Antarctic lakes}, journal = {The ISME Journal}, year = {2014}, month = {10/2013}, keywords = {LTER-MCM}, doi = {10.1038/ismej.2013.190}, url = {http://www.nature.com/ismej/journal/vaop/ncurrent/full/ismej2013190a.html}, author = {Trista J. Vick-Majors and John C. Priscu and Linda A. Amaral-Zettler} } @article {3206, title = {Spring thaw ionic pulses boost nutrient availability and microbial growth in entombed Antarctic Dry Valley cryoconite holes}, journal = {Frontiers in Microbiology}, volume = {5}, year = {2014}, month = {12/2014}, abstract = {

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

}, keywords = {LTER-MCM}, doi = {10.3389/fmicb.2014.00694}, url = {http://journal.frontiersin.org/article/10.3389/fmicb.2014.00694/abstract}, author = {Telling, J. and Alexandre M. Anesio and Martyn Tranter and Andrew G Fountain and Thomas H. Nylen and Hawkings, Jon and Singh, Virendra B. and Kaur, Preeti and Musilova, Michaela and Wadham, J. L.} } @article {3217, title = {Antarctic Thresholds - Ecosystem Resilience and Adaptation (AnT-ERA), a new SCAR-biology programme}, journal = {Polarforschung}, volume = {82}, year = {2013}, month = {10/2013}, pages = {147-150.}, chapter = {147}, abstract = {

Stresses on Antarctic ecosystems result from environmental change, including extreme events, and from (other) human impacts. Consequently, Antarctic habitats are changing, some at a rapid pace while others are relatively stable. A cascade of responses from molecular through organismic to the community level are expected. The differences in biological complexity and evolutionary histories between both polar regions and the rest of the planet suggest that stresses on polar ecosystem function may have fundamentally different outcomes from those at lower latitudes. Polar ecosystem processes are therefore key to informing wider ecological debate about the nature of stability and potential changes across the biosphere. The main goal of AnT-ERA is to facilitate the science required to examine changes in biological processes in Antarctic and sub-Antarctic marine-, freshwater and terrestrial ecosystems. Tolerance limits, as well as thresholds, resistance and resilience to environmental change will be determined. AnT-ERA is classified into three overlapping themes, which represent three levels of biological organisation: (1) molecular and physiological performance, (2) population processes and species traits, (3) ecosystem function and services.

}, keywords = {LTER-MCM}, url = {http://epic.awi.de/34238/1/Polarforschung_82-2_147-150.pdf}, author = {Gutt, J. and Byron Adams and T Bracegirdle and Cowan, D. and Vonda Cummings and di Prisco, G. and Gradinger, R. and Isla, E. and McIntyre, T. and Murphy, E and Lloyd S. Peck and I.R. Schloss and Smith, C. and Suckling, C. C. and Takahashi, A. and Diana H. Wall and J.C. Xavier} } @article {1084, title = {Environmental controls over bacterial communities in polar desert soils}, journal = {Ecosphere}, volume = {4}, year = {2013}, month = {10/2013}, pages = {art127}, keywords = {LTER-MCM}, doi = {10.1890/ES13-00048.1}, author = {Kevin M. Geyer and Adam E. Altrichter and David J. Van Horn and Cristina D. Takacs-Vesbach and Michael N. Gooseff and John E. Barrett} } @article {1092, title = {Factors Controlling Soil Microbial Biomass and Bacterial Diversity and Community Composition in a Cold Desert Ecosystem: Role of Geographic Scale}, journal = {PLoS ONE}, volume = {8}, year = {2013}, month = {06/2013}, pages = {e66103}, keywords = {LTER-MCM}, doi = {10.1371/journal.pone.0066103.s003}, url = {http://www.plosone.org/article/info\%3Adoi\%2F10.1371\%2Fjournal.pone.0066103}, author = {David J. Van Horn and Van Horn, M. Lee and John E. Barrett and Michael N. Gooseff and Adam E. Altrichter and Kevin M. Geyer and Lydia H. Zeglin and Cristina D. Takacs-Vesbach} } @article {1075, title = {The Life Cycle of the Antarctic Nematode Plectus murrayi Under Laboratory Conditions.}, journal = {Journal of nematology}, volume = {45}, year = {2013}, month = {2013 Mar}, pages = {39-42}, keywords = {LTER-MCM}, url = {http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3625130/}, author = {Cecilia M. Tomasel and Byron Adams and Fernando G. Tomasel and Diana H. Wall} } @mastersthesis {4093, title = {Resource Legacies and Priming Regulate Microbial Communities in Antarctica{\textquoteright}s Dry Valleys}, volume = {M.S.}, year = {2013}, school = {Brigham Young University}, type = {masters}, address = {Provo, UT}, abstract = {

Multiple mechanisms control bacterial community structure but two in particular, the \"legacy\" of past environmental conditions, and the \"priming\" of bacteria to respond to seasonal or reoccurring fluctuations in resources, have the potential to determine both bacterial communities, as well as, temporal shifts in active bacterial taxa. To begin to evaluate the legacy effects of resources on microbial communities, we added four limiting resources annually (i.e., water only; C-mannitol + water; N-NH4NO3 + water; and C, N + water) and measured shifts in bacterial community composition after seven years in a cold desert ecosystem in the McMurdo Dry Valleys, Antarctica. Further, to investigate the ecological significance of priming, we conducted a series of stable isotope probing experiments (i.e., 18O-DNA SIP with 18O-labeled water, 13C-DNA SIP with 13C-labeled mannitol, 15N-DNA with 15N- NH4NO3, and a combined C and N SIP) and characterized the responding (i.e., isotopically labeled) and seed bank (i.e., unlabeled) bacterial communities. We performed each of the SIPs in soil microcosms corresponding to a single resource manipulation (e.g., 13C-labeled mannitol in C addition soils). We hypothesized that all long-term additions of nutrients and water will lead to a distinct bacterial community\—a legacy effect due to the nutrient and water impoverished state of Antarctica soils. We also hypothesized that the stronger the legacy effects demonstrated by a specific community the more adapted or primed bacterial species will be to take advantage of the resource and respond. As hypothesized, resource additions created distinct bacterial legacy but to different degrees among the treatments. The extent of the resource legacy effects was greatest in the CN, intermediate in water and N, and lowest in C communities relative to the control communities, suggesting that C induced changes in communities were intensified by tandem N additions and that water alone created a more distinct legacy than water and C additions combined. Contrary to our hypothesis, the stronger the legacy effects, the less adapted or primed the community was to take advantage of resource additions. For example, the CN treatment that induced the greatest effect on bacterial communities had the lowest number of species (20.9\%) in common between the responding and seed bank communities. This inverse relationship may be due to only two species (i.e., Arthrobacter, Actinobacteria and Massilia, Betaproteobacteria) really being primed to take advantage of CN and these species constituting over 75\% of the seed bank community. Water, N, and C additions had similar levels of priming with 38.4\%, 41.4\%, and 36.3\% of the responding species being present in the seed bank community, respectively. But of these three treatments, only the priming with water resulted in a unique responding community, suggesting that water, a universal bacterial resource, was enough to prime bacteria. Furthermore, water generates the most diverse responding community of all the resources with stemming from all of the fourteen dominant phyla. We did find patterns of ecological coherence among the responders, especially in the major responders (i.e., responders that increased in relative recovery by at least ten-fold). These responders were predominantly found in only three phyla (i.e., Actinobacteria, Bacteriodetes, and Gammaproteobacteria) regardless of resource addition. Alternatively minor responders (i.e., responders that increased in relative recovery at least two-fold) were contained in fourteen different phyla with specific taxa stimulated by CN (i.e., Betaproteobacteria) and N and water (i.e., Deltaproteobacteria). Further, resource additions elicited responses from 37\% of bacterial species with species specializing on a specific resource (e.g., Chloroflexi) or being a generalist (e.g., Planctomycetes and Gammaproteobacteria). Our results offer the first direct links between legacy and priming effects on bacterial community composition and demonstrate that these mechanisms are not always complimentary leading to the formation of similar communities but may both be essential to maintain the high levels of bacterial diversity. Further, all resources produced elicited responders that were either specialists of generalists demonstrating that even bacteria in the extreme environment of Antarctica respond to pulses of resources.

}, keywords = {LTER-MCM, 454 pyrosequencing, Antarctica, bacteria, microbial ecology, soil, soil ecology, stable isotope probing, target metagenomics}, url = {http://hdl.lib.byu.edu/1877/etd6229}, author = {Saurey, Sabrina D.}, editor = {Aanderud, Zachary T.} } @article {1099, title = {Understanding Terrestrial Ecosystem Response to Antarctic Climate Change}, journal = {Eos, Transactions American Geophysical Union}, volume = {94}, year = {2013}, month = {01/2013}, pages = {33 - 33}, keywords = {LTER-MCM}, doi = {10.1002/2013EO030009}, url = {http://onlinelibrary.wiley.com/doi/10.1002/2013EO030009/abstract}, author = {Joseph S. Levy and W. Berry Lyons and Byron Adams} } @article {1105, title = {Antarctic Tardigrada: a first step in understanding molecular operational taxonomic units (MOTUs) and biogeography of cryptic meiofauna}, journal = {Invertebrate Systematics}, volume = {26}, year = {2012}, month = {12/2012}, pages = {526}, keywords = {LTER-MCM}, doi = {10.1071/IS12034}, author = {Czechowski, Paul and Sands, Chester J. and Byron Adams and D{\textquoteright}Haese, Cyrille A. and John A. E. Gibson and McInnes, Sandra J. and Stevens, Mark I.} } @article {1108, title = {Cross-biome metagenomic analyses of soil microbial communities and their functional attributes}, journal = {Proceedings Bational Academy of Sciences}, year = {2012}, month = {11/2012}, keywords = {LTER-MCM}, doi = {10.1073/pnas.1215210110}, url = {www.pnas.org/cgi/doi/10.1073/pnas.1215210110}, author = {Noah Fierer and Jonathan W. Leff and Byron Adams and Uffe N. Nielsen and Scott T. Bates and Christian L. Lauber and Sarah Owens and Jack A. Gilbert and Diana H. Wall and J. Gregory Caporaso} } @article {1122, title = {The ecology of pulse events: insights from an extreme climatic event in a polar desert ecosystem}, journal = {Ecosphere}, volume = {3}, year = {2012}, month = {02/2012}, pages = {art17}, keywords = {LTER-MCM}, doi = {10.1890/ES11-00325.1}, url = {http://www.esajournals.org/doi/abs/10.1890/ES11-00325.1}, author = {Uffe N. Nielsen and Diana H. Wall and Byron Adams and Ross A. Virginia and Ball, Becky and Michael N. Gooseff and Diane M. McKnight} } @book {1123, title = {Poisson Reconstruction of Extreme Submersed Environments: The ENDURANCE Exploration of an Under-Ice Antarctic Lake}, series = {Advances in Visual Computing. ISVC 2012. Lecture Notes in Computer Science.}, volume = {7431}, year = {2012}, pages = {394 - 403}, publisher = {Springer Berlin Heidelberg}, organization = {Springer Berlin Heidelberg}, address = {Berlin, Heidelberg}, abstract = {

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.

}, keywords = {LTER-MCM}, isbn = {978-3-642-33179-4}, doi = {10.1007/978-3-642-33179-4_38}, url = {http://www.springerlink.com/content/hg97w43588229087/}, author = {Alessandro Febretti and Kristof Richmond and Gulati, Shilpa and Flesher, Christopher and Hogan, Bartholomew P. and Andrew Johnson and Stone, William C. and John C. Priscu and Peter T. Doran}, editor = {Bebis, George and Boyle, Richard and Parvin, Bahram and Koracin, Darko and Fowlkes, Charless and Wang, Sen and Choi, Min-Hyung and Mantler, Stephan and Schulze, J{\"u}rgen and Acevedo, Daniel and Mueller, Klaus and Papka, Michael} } @article {1102, title = {Thawing permafrost alters nematode populations and soil habitat characteristics in an Antarctic polar desert ecosystem}, journal = {Pedobiologia}, volume = {55}, year = {2012}, month = {3/2012}, pages = {75 - 81}, keywords = {LTER-MCM}, doi = {10.1016/j.pedobi.2011.11.001}, url = {http://www.sciencedirect.com/science/article/pii/S0031405611001156}, author = {Smith, T.E. and Diana H. Wall and Hogg, I and Byron Adams and Uffe N. Nielsen and Ross A. Virginia} } @article {1132, title = {Antarctic nematode communities: observed and predicted responses to climate change}, journal = {Polar Biology}, volume = {34}, year = {2011}, month = {11/2011}, pages = {1701 - 1711}, keywords = {LTER-MCM}, doi = {10.1007/s00300-011-1021-2}, url = {http://www.springerlink.com/content/v588t5671p1w1323/}, author = {Uffe N. Nielsen and Diana H. Wall and Byron Adams and Ross A. Virginia} } @inbook {1144, title = {Molecular analysis of desiccation survival in Antarctic nematodes}, booktitle = {Molecular and Physiological Basis of Nematode Survival}, year = {2011}, pages = {205-232}, publisher = {CABI International}, organization = {CABI International}, address = {Wallingford}, keywords = {LTER-MCM}, isbn = {9781845936877}, author = {Bishwo N. Adhikari and Byron Adams} } @book {1145, title = {Molecular and physiological basis of nematode survival: Molecular analyses of desiccation survival in Antarctic nematodes.}, year = {2011}, pages = {205 - 232}, publisher = {CABI}, organization = {CABI}, address = {Wallingford}, keywords = {LTER-MCM}, doi = {10.1079/9781845936877.0205}, author = {Bishwo N. Adhikari and Byron Adams}, editor = {Perry, R. N. and Wharton, D. A.} } @article {1134, title = {Molecular study of worldwide distribution and diversity of soil animals}, journal = {Proceedings of the National Academy of Sciences}, volume = {108}, year = {2011}, month = {10/2011}, pages = {17720 - 17725}, keywords = {LTER-MCM}, doi = {10.1073/pnas.1103824108}, author = {Tiehang Wu and Edward Ayres and Richard D. Bardgett and Diana H. Wall and James R. Garey} } @article {1126, title = {Nematode communities of Byers Peninsula, Livingston Island, maritime Antarctica}, journal = {Antarctic Science}, volume = {23}, year = {2011}, month = {8/2011}, pages = {349 - 357}, keywords = {LTER-MCM}, doi = {10.1017/S0954102011000174}, author = {Uffe N. Nielsen and Diana H. Wall and Li, Grace and Toro, Manuel and Byron Adams and Ross A. Virginia} } @article {1155, title = {The Antarctic Nematode Plectus murrayi: An Emerging Model to Study Multiple Stress Survival}, journal = {Cold Spring Harbor Protocols}, volume = {2010}, year = {2010}, month = {11/2010}, pages = {pdb.emo142 - pdb.emo142}, keywords = {LTER-MCM}, doi = {10.1101/pdb.emo142}, author = {Bishwo N. Adhikari and Cecilia M. Tomasel and Li, G and Diana H. Wall and Byron Adams} } @article {1156, title = {Culturing the Antarctic Nematode Plectus murrayi}, journal = {Cold Spring Harbor Protocols}, volume = {2010}, year = {2010}, month = {11/2010}, pages = {pdb.prot5522 - pdb.prot5522}, keywords = {LTER-MCM}, doi = {10.1101/pdb.prot5522}, url = {http://cshprotocols.cshlp.org/content/2010/11/pdb.emo142.short}, author = {Bishwo N. Adhikari and Cecilia M. Tomasel and Li, G and Diana H. Wall and Byron Adams} } @article {1163, title = {Effect of slow desiccation and freezing on gene transcription and stress survival of an Antarctic nematode}, journal = {Journal of Experimental Biology}, volume = {213}, year = {2010}, month = {06/2010}, pages = {1803 - 1812}, keywords = {LTER-MCM}, doi = {10.1242/jeb.032268}, author = {Bishwo N. Adhikari and Diana H. Wall and Byron Adams} } @article {1147, title = {Experimentally increased snow accumulation alters soil moisture and animal community structure in a polar desert}, journal = {Polar Biology}, volume = {33}, year = {2010}, month = {7/2010}, pages = {897 - 907}, keywords = {LTER-MCM}, doi = {10.1007/s00300-010-0766-3}, author = {Edward Ayres and Johnson N. Nkem and Diana H. Wall and Byron Adams and John E. Barrett and Breana L. Simmons and Ross A. Virginia and Andrew G Fountain} } @phdthesis {4442, title = {Genomic analysis of nematode-environment interaction}, volume = {Ph.D.}, year = {2010}, month = {08/2010}, school = {Brigham Young University}, type = {doctoral}, address = {Provo, UT}, abstract = {

The natural environments of organisms present a multitude of biotic and abiotic challenges that require both short-term ecological and long-term evolutionary responses. Though most environmental response studies have focused on effects at the ecosystem, community and organismal levels, the ultimate controls of these responses are located in the genome of the organism. Soil nematodes are highly responsive to, and display a wide variety of responses to changing environmental conditions, making them ideal models for the study of organismal interactions with their environment. In an attempt to examine responses to environmental stress (desiccation and freezing), genomic level analyses of gene expression during anhydrobiosis of the Antarctic nematode Plectus murrayi was undertaken. An EST library representative of the desiccation induced transcripts was established and the transcripts differentially expressed during desiccation stress were identified. The expressed genome of P. murrayi showed that desiccation survival in nematodes involves differential expression of a suite of genes from diverse functional areas, and constitutive expression of a number of stress related genes. My study also revealed that exposure to slow desiccation and freezing plays an important role in the transcription of stress related genes, improves desiccation and freezing survival of nematodes. Deterioration of traits essential for biological control has been recognized in diverse biological control agents including insect pathogenic nematodes. I studied the genetic mechanisms behind such deterioration using expression profiling. My results showed that trait deterioration of insect pathogenic nematode induces substantial overall changes in the nematode transcriptome and exhibits a general pattern of metabolic shift causing massive changes in metabolic and other processes. Finally, through field observations and molecular laboratory experiments the validity of the growth rate hypothesis in natural populations of Antarctic nematodes was tested. My results indicated that elemental stoichiometry influences evolutionary adaptations in gene expression and genome evolution. My study, in addition to providing immediate insight into the mechanisms by which multicellular animals respond to their environment, is transformative in its potential to inform other fundamental ecological and evolutionary questions, such as the evolution of life-history patterns and the relationship between community structure and ecological function in ecosystems.

}, keywords = {LTER-MCM, anhydrobiosis, Antarctic nematode, comparative transcriptomics, complementary DNA library, desiccation, functional analysis, Heterorhabditis bacteriophora, McMurdo Dry Valleys, microarray analysis, Plectus murrayi, quantative real-time polymerase chain reaction, Scottnema lindsayae, stoichiometry, stress survival, subtractive hybridization, trait deterioration, transcriptional profiling}, url = {https://scholarsarchive.byu.edu/etd/2578}, author = {Bishwo N. Adhikari and Byron Adams} } @mastersthesis {4082, title = {Landscape history and contemporary environmental drivers of microbial community structure and function}, volume = {MS}, year = {2010}, school = {Virginia Tech}, type = {masters}, address = {Blacksburg, VA}, abstract = {

Recent work in microbial ecology has focused on elucidating controls over biogeographic patterns and connecting microbial community composition to ecosystem function. My objective was to investigate the relative influences of landscape legacies and contemporary environmental factors on the distribution of soil microbial communities and their contribution to ecosystem processes across a glacial till sequence in Taylor Valley, Antarctica. Within each till unit, I sampled from dry areas and areas with visible evidence of recent surface water movement generated by seasonal melting of ephemeral snow packs and hillslope ground ice. Using T-RFLP 16S rRNA gene profiles of microbial communities, I analyzed the contribution of till and environmental factors to community similarity, and assessed the functional potential of the microbial community using extracellular enzyme activity assays. Microbial communities were influenced by geochemical differences among both tills and local environments, but especially organized by variables associated with water availability as the first axis of an NMDS ordination was strongly related to shifts in soil moisture content. CCA revealed that tills explained only 3.4\% of the variability in community similarity among sites, while geochemical variables explained 18.5\%. Extracellular enzyme activity was correlated with relevant geochemical variables reflecting the influence of nutrient limitation on microbial activity. In addition, enzyme activity was related to changes in community similarity, particularly in wet environments with a partial Mantel correlation of 0.32. These results demonstrate how landscape history and environmental conditions can shape the functional potential of a microbial community mediated through shifts in microbial community composition.

}, keywords = {LTER-MCM, community similarity, extracellular enzyme activity, McMurdo Dry Valleys, microbial biogeography, soil geochemistry, T-RFLP}, url = {http://hdl.handle.net/10919/31883}, author = {Adam E. Altrichter}, editor = {John E. Barrett} } @article {1152, title = {Latitudinal distribution and mitochondrial DNA (COI) variability of Stereotydeus spp. (Acari: Prostigmata) in Victoria Land and the central Transantarctic Mountains}, journal = {Antarctic Science}, volume = {22}, year = {2010}, month = {12/2010}, pages = {749 - 756}, keywords = {LTER-MCM}, doi = {10.1017/S0954102010000659}, author = {Demetras, Nicholas J. and Hogg, I and Banks, Jonathan C. and Byron Adams} } @article {1176, title = {Sediment Melt Dynamics in Permanent Antarctic Lake Ice}, journal = {Arctic, Antarctic, and Alpine Research}, volume = {42}, year = {2010}, pages = {57-66}, keywords = {LTER-MCM}, doi = {10.1657/1938-4246-42.1.57}, url = {http://mcmlter.lternet.edu/reports/lakes/JepsenEtAl2010SedimentMeltMigration.pdf}, author = {Steven M. Jepsen and Edward E. Adams and John C. Priscu} } @article {1197, title = {Accelerate Synthesis in Ecology and Environmental Sciences.}, journal = {Bioscience}, volume = {59}, year = {2009}, pages = {699-701}, keywords = {LTER-MCM}, doi = {LTER}, author = {Carpenter, S and Lundberg, P and Mangel, M and Merchant, N and Murdoch, W and Palmer, M and Debra P. C. Peters and Pickett, S and Smith, K and Diana H. Wall and Maggie K. Zimmerman and Armbrust, E and Arzberger, E and F. S. Chapin and Elser, J and Hackett, E and Ives, A and Kareiva, P and Leibold, M} } @article {1184, title = {A Contemporary Microbially Maintained Subglacial Ferrous "Ocean"}, journal = {Science}, volume = {324}, year = {2009}, month = {04/2009}, pages = {397-400}, type = {Journal}, abstract = {

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

}, keywords = {LTER-MCM, Biggie}, doi = {10.1126/science.1167350}, url = {http://www.sciencemag.org/content/324/5925/397.short}, author = {Jill A. Mikucki and Pearson, A and Johnston, D and Turchyn, A and Farquhar, J and Schrag, D and Anbar, A and John C. Priscu and Lee, P} } @article {1182, title = {Desiccation survival in an Antarctic nematode: molecular analysis using expressed sequenced tags.}, journal = {BMC GENOMICS}, volume = {10}, year = {2009}, month = {09/2009}, pages = {69}, keywords = {LTER-MCM}, doi = {10.1186/1471-2164-10-69}, url = {http://www.biomedcentral.com/1471-2164/10/69}, author = {Bishwo N. Adhikari and Diana H. Wall and Byron Adams} } @article {1180, title = {Environmental DNA sequencing primers for eutardigrades and bdelloid rotifers}, journal = {BMC Ecology}, volume = {9}, year = {2009}, month = {11/2009}, pages = {25}, keywords = {LTER-MCM}, doi = {10.1186/1472-6785-9-25}, author = {Robeson, Michael S and Costello, Elizabeth K and Freeman, Kristen R and Whiting, Jeremy and Byron Adams and Martin, Andrew P and Schmidt, Steve K} } @article {1190, title = {Long-term experimental warming reduces soil nematode populations in the McMurdo Dry Valleys, Antarctica}, journal = {Soil Biology \& Biochemistry}, volume = {41}, year = {2009}, pages = {2052-2060}, keywords = {LTER-MCM}, doi = {10.1016/j.soilbio.2009.07.009}, author = {Breana L. Simmons and Diana H. Wall and Byron Adams and Edward Ayres and John E. Barrett and Ross A. Virginia} } @article {1198, title = {Managing for ocean biodiversity to sustain marine ecosystem services}, journal = {FRONTIERS IN ECOLOGY AND THE ENVIRONMENT}, volume = {7}, year = {2009}, pages = {204-211}, keywords = {LTER-MCM}, doi = {LTER}, author = {Palumbi, S and Norse, E and Stachowicz, J and Diana H. Wall and Sandifer, P and Allan, J and Beck, M and Fautin, D and Fogerty, M and Halpern, B and Incze, L and Leong, J} } @article {1200, title = {Molecular profiling of soil animal diversity in natural ecosystems: incongruence of molecular and morphological results}, journal = {Soil Biology and Biochemistry}, year = {2009}, pages = {849-857}, keywords = {LTER-MCM}, doi = {10.1016/j.soilbio.2009.02.003}, author = {Wu, T and Edward Ayres and Li, G and Richard D. Bardgett and Diana H. Wall and James R. Garey} } @article {1194, title = {State of the Antarctic and the Southern Ocean climate system,}, journal = {Review of Geophysics}, volume = {47}, year = {2009}, keywords = {LTER-MCM}, doi = {LTER}, author = {Paul A. Mayewski and David Bromwich and Campbell, H and Hamilton, G and W. Berry Lyons and Maasch, K and Aoki, S and Xiao, C and van Ommen, T and Meredith, M and Summerhayes, C and Turner, J and Worby, A and John E. Barrett and Casassa, G and Bertler, N and T Bracegirdle} } @article {1195, title = {Terrestrial mesofauna in above- and below-ground habitats: Taylor Valley, Antarctica}, journal = {Polar Biology}, volume = {32}, year = {2009}, pages = {1549-1558}, keywords = {LTER-MCM}, doi = {LTER}, author = {Breana L. Simmons and Diana H. Wall and Byron Adams and Edward Ayres and John E. Barrett and Ross A. Virginia} } @article {1183, title = {Where{\textquoteright}s the ecology in molecular ecology?}, journal = {Oikos}, volume = {118}, year = {2009}, month = {05/2009}, pages = {1601-1609}, keywords = {LTER-MCM}, doi = {10.1111/j.1600-0706.2009.17557.x}, author = {Jerry B. Johnson and Scott M. Peat and Byron Adams} } @article {1208, title = {Bacteriophage in polar inland waters}, journal = {Extremophiles}, volume = {12}, year = {2008}, pages = {167-175}, keywords = {LTER-MCM}, doi = {LTER}, url = {/reports/lakes/SawstromEtAl2008Bacteriophage.pdf}, author = {Sawstrom, C and John T. Lisle and Alexandre M. Anesio and John C. Priscu and Johanna Laybourn-Parry} } @article {1210, title = {Decline in a dominant invertebrate species contributes to altered carbon cycling in a low-diversity soil ecosystem}, journal = {Global Change Biology}, volume = {14}, year = {2008}, pages = {1734-1744}, keywords = {LTER-MCM}, doi = {LTER}, author = {John E. Barrett and Ross A. Virginia and Diana H. Wall and Byron Adams} } @article {1211, title = {Effects of Human Trampling on Populations of Soil Fauna in the McMurdo Dry Valleys, Antarctica.}, journal = {Conservation Biology}, volume = {22}, year = {2008}, month = {12/2008}, pages = {1544-1551}, abstract = {

Antarctic ecosystems are often considered nearly pristine because levels of anthropogenic disturbance are extremely low there. Nevertheless, over recent decades there has been a rapid increase in the number of people, researchers and tourists, visiting Antarctica. We evaluated, over 10 years, the direct impact of foot traffic on the abundance of soil animals and soil properties in Taylor Valley within the McMurdo Dry Valleys region of Antarctica. We compared soils from minimally disturbed areas with soils from nearby paths that received intermediate and high levels of human foot traffic (i.e., up to approximately 80 passes per year). The nematodes Scottnema lindsayae and Eudorylaimus sp. were the most commonly found animal species, whereas rotifers and tardigrades were found only occasionally. On the highly trampled footpaths, abundance of S. lindsayae and Eudorylaimus sp. was up to 52 and 76\% lower, respectively, than in untrampled areas. Moreover, reduction in S. lindsayae abundance was more pronounced after 10 years than 2 years and in the surface soil than in the deeper soil, presumably because of the longer period of disturbance and the greater level of physical disturbance experienced by the surface soil. The ratio of living to dead Eudorylaimus sp. also declined with increased trampling intensity, which is indicative of increased mortality or reduced fecundity. At one site there was evidence that high levels of trampling reduced soil CO2 fluxes, which is related to total biological activity in the soil. Our results show that even low levels of human traffic can significantly affect soil biota in this ecosystem and may alter ecosystem processes, such as carbon cycling. Consequently, management and conservation plans for Antarctic soils should consider the high sensitivity of soil fauna to physical disturbance as human presence in this ecosystem increases.

}, keywords = {LTER-MCM}, doi = {10.1111/j.1523-1739.2008.01034.x}, author = {Edward Ayres and Johnson N. Nkem and Diana H. Wall and Byron Adams and John E. Barrett and Broos, E and Andrew N. Parsons and Powers, Laura E. and Breana L. Simmons and Ross A. Virginia} } @inbook {1213, title = {Glacial ecosystems}, booktitle = {Ecological Monographs}, volume = {78}, year = {2008}, pages = {41-67}, edition = {1}, abstract = {
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.
}, keywords = {LTER-MCM, Biggie, snow ecology}, doi = {10.1890/07-0187.1}, url = {http://dx.doi.org/10.1890/07-0187.1}, author = {Hodson, A and Alexandre M. Anesio and Martyn Tranter and Andrew G Fountain and Osborn, M and John C. Priscu and Johanna Laybourn-Parry and Sattler, B} } @article {1202, title = {Global decomposition experiment shows soil animal impacts on decomposition are climate dependent}, journal = {Global Change Biology}, volume = {14}, year = {2008}, month = {11/2008}, pages = {2661-2677}, keywords = {LTER-MCM}, doi = {10.1111/j.1365-2486.2008.01672.x}, url = {http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2486.2008.01672.x/full}, author = {Diana H. Wall and Mark A. Bradford and Mark G. StJohn and John A. Trofymow and Valerie Behan-Pelletier and David E. Bignell and J. Mark Dangerfield and William J. Parton and Josef Rusek and Winfried Voigt and Volkmar Wolters and Holley Zadeh Gardel and Fred O. Ayuke and Richard Bashford and Olga I. Beljakova and Patrick J. Bohlen and Alain Brauman and Stephen Flemming and Joh R. Henschel and Dan L. Johnson and T. Hefin Jones and Marcela Kovarova and J. Marty Kranabetter and Les Kutny and Kuo-Chuan Lin and Mohamed Maryati and Dominique Masse and Andrei Pokarzhevskii and Homathevi Rahman and Millor G. Sabara and Joerg-Alfred Salamon and Michael J. Swift and Amanda Varela and Heraldo L. Vasconcelos and Don White and Xiaming Zou} } @article {1201, title = {Reply to comment by K. Gajewski on {\textquotedblleft}Abrupt environmental change in Canada{\textquoteright}s northernmost lake{\textquotedblright}}, journal = {Geophysical Research Letters}, volume = {35}, year = {2008}, month = {2008}, keywords = {LTER-MCM}, doi = {10.1029/2007GL032889}, url = {http://www.agu.org/pubs/crossref/2008/2007GL032889.shtml}, author = {Dermot Antoniades and Catherine Crawley and Douglas, Marianne S. V. and Pienitz, R and Dale T. Andersen and Peter T. Doran and Ian Hawes and Pollard, W and Warwick F. Vincent} } @article {1224, title = {Stoichiometry of soil enzyme activity at global scale.}, journal = {Ecology Letters}, volume = {11}, year = {2008}, pages = {1252-1264}, keywords = {LTER-MCM}, doi = {LTER}, author = {Sinsabaugh, R and Gallo, M and Gartner, T and Hobbie, S and Holland, K and Keeler, B and Powers, J and Stursova, M and Cristina D. Takacs-Vesbach and Waldrop, M and Wallenstein, M and Lauber, M and Zak, D and Lydia H. Zeglin and Weintraub, M and Ahmed, B and Allison, S and Crenshaw, C and Contosta, A and Cusack, D and Frey, S} } @article {1235, title = {Reactivation of a cryptobiotic stream ecosystem in the McMurdo Dry Valleys, Antarctica: A long-term geomorphological experiment}, journal = {Geomorphology}, volume = {89}, year = {2007}, month = {09/2007}, pages = {186-204}, keywords = {LTER-MCM}, doi = {10.1016/j.geomorph.2006.07.025}, author = {Diane M. McKnight and Cathy M. Tate and Edmund D. Andrews and Dev K. Niyogi and Cozzetto, K and Kathleen A. Welch and W. Berry Lyons and D. G. Capone} } @article {1248, title = {The southernmost worm, Scottnema lindsayae (Nematoda): diversity, dispersal and ecological stability.}, journal = {Polar Biology}, volume = {30}, year = {2007}, pages = {809-815}, keywords = {LTER-MCM}, doi = {LTER}, author = {Byron Adams and Diana H. Wall and Gozel, U and Dillman, A and Chaston, J and Hogg, I} } @article {1252, title = {Unique similarity of faunal communities across aquatic terrestrial interfaces in a polar desert ecosystem}, journal = {Ecosystems}, year = {2007}, keywords = {LTER-MCM}, doi = {LTER}, author = {Edward Ayres and Diana H. Wall and Byron Adams and John E. Barrett and Ross A. Virginia} } @article {1263, title = {Biotic interactions in Antarctic terrestrial ecosystems: Are they a factor?}, journal = {Soil Biology and Biochemistry}, volume = {38}, year = {2006}, pages = {3035-3040}, keywords = {LTER-MCM}, doi = {10.1016/j.soilbio.2006.04.026}, url = {http://www.sciencedirect.com/science/article/pii/S0038071706002173}, author = {Hogg, I and Diana H. Wall and Craig S Cary and Convey, K and Newsham, K and ODonnell, G and Byron Adams and Aislabie, J and Francesco Frati and Stevens, M} } @article {1264, title = {Co-variation in soil biodiversity and biogeochemistry in Northern and Southern Victoria Land, Antarctica}, journal = {Antarctic Science}, volume = {18}, year = {2006}, pages = {535-548}, keywords = {LTER-MCM}, doi = {10.1017/S0954102006000587}, url = {https://www.cambridge.org/core/journals/antarctic-science/article/covariation-in-soil-biodiversity-and-biogeochemistry-in-northern-and-southern-victoria-land-antarctica/C3514C28DB75F3A19DB5F266D4B1B56E}, author = {John E. Barrett and Ross A. Virginia and Diana H. Wall and Craig S Cary and Byron Adams and Hacker, A and Aislabie, J} } @article {1265, title = {Diversity and distribution of Victoria Land biota}, journal = {Soil Biology and Biochemistry}, volume = {38}, year = {2006}, pages = {3003-3018}, keywords = {LTER-MCM}, doi = {10.1016/j.soilbio.2006.04.030}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0038071706002215}, author = {Byron Adams and Connell, L and Peter Convey and Fell, J and Francesco Frati and Hogg, I and Newsham, K and O{\textquoteright}Donnell, A and Russell, N and Seppelt, R and Stevens, M and Richard D. Bardgett and Edward Ayres and Diana H. Wall and Aislabie, J and Bamforth, S and Bargagli, R and Craig S Cary and Cavacini, P} } @article {1268, title = {Fuel movement between grain boundaries in ice}, journal = {Cold Regions Science and Technology}, volume = {45}, year = {2006}, pages = {158-165}, keywords = {LTER-MCM}, doi = {LTER}, author = {Steven M. Jepsen and Edward E. Adams and John C. Priscu} } @article {1269, title = {Glacial and postglacial sedimentation in the Fryxell basin, Taylor Valley, Southern Victoria Land, Antarctica}, journal = {Palaeography, Palaeoclimatology, Palaeoecology}, volume = {341}, year = {2006}, pages = {320}, keywords = {LTER-MCM}, doi = {LTER}, author = {Wagner, B and Melles, M and Peter T. Doran and Kenig, Fabien and Forman, S and Pierau, R and Allan, P} } @article {1277, title = {A synthesis of soil biodiversity and ecosystem functioning in Victoria Land, Antarctica}, journal = {Soil Biology and Biochemistry}, volume = {38}, year = {2006}, pages = {3001-3002}, keywords = {LTER-MCM}, doi = {LTER}, author = {Diana H. Wall and Byron Adams and John E. Barrett and D. W. Hopkins} } @article {1278, title = {Terrestrial ecosystem processes of Victoria Land, Antarctica}, journal = {Soil Biology and Biochemistry}, volume = {38}, year = {2006}, pages = {3019-3034}, keywords = {LTER-MCM}, doi = {LTER}, author = {John E. Barrett and Johnson N. Nkem and Sletten, R and Steltzer, H and Diana H. Wall and Wallenstein, M and Ross A. Virginia and D. W. Hopkins and Aislabie, J and Bargagli, R and Bockheim, J and Campbell, I and W. Berry Lyons and Daryl L. Moorhead} } @article {1279, title = {Wind dispersal of soil invertebrates in the McMurdo Dry Valleys, Antarctica}, journal = {Polar Biology}, volume = {29}, year = {2006}, pages = {346-352}, abstract = {

Dispersal of soil organisms is crucial for their spatial distribution and adaptation to the prevailing conditions of the Antarctic Dry Valleys. This study investigated the possibility of wind dispersal of soil invertebrates within the dry valleys. Soil invertebrates were evaluated in (1) pockets of transported sediments to lake ice and glacier surfaces, (2) wind-transported dust particles in collection pans (Bundt pans) 100\ cm above the soil surface, and (3) sediments transported closer to the surface (\<50\ cm) and collected in open top chambers (OTCs). Invertebrates were extracted and identified. Nematodes were identified to species and classified according to life stage and sex. Three species of nematodes were recovered and\ Scottnema lindsayae\ was the most dominant. There were more juveniles (\∼71\%) in the transported sediments than adults (29\%). Tardigrades and rotifers were more abundant in sediments on lake and glacier surfaces while nematodes were more abundant in the dry sediment collections of Bundt pans and OTCs. The abundance of immobile (dead) nematodes in the Bundt pans and OTCs was three times greater than active (live) nematodes. Anhydrobiosis constitutes a survival mechanism that allows wind dispersal of nematodes in the McMurdo Dry Valleys. Our results show that soil invertebrates are dispersed by wind in the Dry Valleys and are viable in ice communities on lake surfaces and glaciers.

}, keywords = {LTER-MCM, Biggie}, doi = {10.1007/s00300-005-0061-x}, url = {http://link.springer.com/content/pdf/10.1007\%2Fs00300-005-0061-x}, author = {Johnson N. Nkem and Diana H. Wall and Ross A. Virginia and John E. Barrett and Broos, E and Porazinska, D and Byron Adams} } @inbook {1304, title = {Perennial Antarctic lake ice: A refuge for cyanobacteria in an extreme environment}, booktitle = {Life in Ancient Ice}, year = {2005}, pages = {22-49}, publisher = {Princeton University Press}, organization = {Princeton University Press}, keywords = {LTER-MCM}, url = {http://www.montana.edu/lkbonney/DOCS/Publications/PriscuEtAl2005CyanobacteriaRefuge.pdf}, author = {John C. Priscu and Edward E. Adams and Hans W. Paerl and Christian H. Fritsen and John E. Dore and John T. Lisle and Craig F. Wolf and Jill A. Mikucki}, editor = {S. O. Rogers and J. Castello} } @inbook {1306, title = {Polar lakes, streams, and springs as analogs for the hydrological cycle on Mars.}, booktitle = {Advances in Astrobiology and Biogeophysics}, year = {2005}, pages = {219-233}, publisher = {Springer Verlag}, organization = {Springer Verlag}, address = {Berlin, Heidelberg}, keywords = {LTER-MCM}, doi = {LTER}, url = {/reports/lakes/McKayEtAl2005StreamsSprings.pdf}, author = {Christopher P. McKay and Dale T. Andersen and Pollard, W and Heldmann, J and Peter T. Doran and Christian H. Fritsen and John C. Priscu} } @inbook {1307, title = {Polar Systems}, booktitle = {Millennium Ecosystem Assessment. Current State and Trends: Findings of the Condition and Trends Working Group}, year = {2005}, pages = {717-743}, publisher = {Island Press}, organization = {Island Press}, keywords = {LTER-MCM}, doi = {LTER}, author = {F. S. Chapin and McGuire, A and Nuttall, M and Ross A. Virginia and Young, O and Zimov, S and Christensen, T and Godduhn, A and Murphy, E and Diana H. Wall and Zockler, C and Berman, M and Callaghan, T and Peter Convey and A. S. Crepin and Danell, K and Hugh W. Ducklow and Forbes, B and Kofinas, G}, editor = {R. Hassan and R. Scholes and N. Ash} } @inbook {1309, title = {Soils, freshwater and marine sediments: the need for integrative landscape science}, booktitle = {Marine Ecology Progress Series}, series = {Theme Section: Bridging the Gap between Aquatic and Terrestrial Ecology.}, volume = {304}, year = {2005}, pages = {302-307}, keywords = {LTER-MCM}, doi = {LTER}, author = {Diana H. Wall and Edward Ayres and Valerie Behan-Pelletier and Covich, A and P.V.R. Snelgrove}, editor = {H. Browman and K. I. Stergiou} } @inbook {1339, title = {Paleolimnology of extreme cold terrestrial and extraterrestrial environments.}, booktitle = {Long-Term Environmental Change in Arctic and Antarctic Lakes}, year = {2004}, pages = {475-507}, publisher = {Kluwer Academic Publishers}, organization = {Kluwer Academic Publishers}, address = {Dordrecht, The Netherlands}, keywords = {LTER-MCM}, isbn = {978-1-4020-2125-1}, author = {Peter T. Doran and John C. Priscu and W. Berry Lyons and Powell, R and Robert J. Poreda and Dale T. Andersen} } @inbook {1348, title = {Vulnerability to global change of ecosystem goods and services driven by soil biota}, booktitle = {Sustaining Biodiversity and Ecosystem Services in Soil and Sediments}, year = {2004}, pages = {101-136}, publisher = {Island Press}, organization = {Island Press}, keywords = {LTER-MCM}, isbn = {1-55963-760-9}, author = {Wardle, D and V.K. Brown and Valerie Behan-Pelletier and St. John, M and Wojtowicz, T and Richard D. Bardgett and Brown, G. G. and Ineson, P. and Lavelle, P and van der Putten, W and Anderson, J. M. and Brussaard, L and H. William Hunt and E. A. Paul and Diana H. Wall}, editor = {Diana H. Wall} } @article {1357, title = {Formation and character of an ancient 19 m ice cover and underlying trapped brine in an}, journal = {Proceedings of National Academy of Sciences}, volume = {100}, year = {2003}, month = {01/2003}, pages = {26-31}, type = {Journal}, keywords = {LTER-MCM}, doi = {10.1073/pnas.222680999}, url = {http://www.pnas.org/content/100/1/26.short}, author = {Peter T. Doran and Christian H. Fritsen and Christopher P. McKay and John C. Priscu and Edward E. Adams} } @article {1402, title = {The influence of soil biodiversity on hydrological pathways and the transfer of materials between terrestrial and aquatic ecosystems}, journal = {Ecosystems}, volume = {4}, year = {2001}, keywords = {LTER-MCM}, author = {Richard D. Bardgett and Anderson, J. M. and Valerie Behan-Pelletier and Brussaard, L and David C. Coleman and Ettma, C and Moldenke, A and Schimel, J and Diana H. Wall} } @article {1406, title = {Retrospective simulation of lake level rise in Lake Bonney based on recent 21-year record: indication of recent climate change in the McMurdo Dry Valleys, Antarctica}, journal = {Journal of Paleolimnology}, volume = {25}, year = {2001}, pages = {477-492}, keywords = {LTER-MCM, Climate Response}, author = {Bomblies, Arne and Diane M. McKnight and Edmund D. Andrews} } @inbook {1407, title = {Soil Biodiversity}, booktitle = {Global Biodiversity in a Changing Environment}, year = {2001}, pages = {47-82}, publisher = {Springer Verlag}, organization = {Springer Verlag}, address = {New York}, keywords = {LTER-MCM}, author = {Diana H. Wall and Gina A. Adams and Andrew N. Parsons}, editor = {F. S. Chapin and Osvaldo E. Sala and E. Huber-Sannwald} } @article {1408, title = {Spectrofluorometric characterization of aquatic fulvic acid for determination of precursor organic material and general structural properties.}, journal = {Limnology and Oceanography}, volume = {46}, year = {2001}, pages = {38-48}, keywords = {LTER-MCM}, author = {Diane M. McKnight and Elizabeth W. Boyer and Paul K. Westerhoff and Peter T. Doran and Thomas Kulbe and Dale T. Andersen} } @article {1425, title = {Biodiversity above and below the surface of soils and sediments: linkages and implications for global change}, journal = {Bioscience}, volume = {50}, year = {2000}, pages = {1043-1048}, keywords = {LTER-MCM}, doi = {10.1641/0006-3568(2000)050[1043:BAABTS]2.0.CO;2}, author = {Gina A. Adams and Diana H. Wall} } @article {1441, title = {Global biodiversity scenarios for the year 2100}, journal = {Science}, volume = {287}, year = {2000}, pages = {1770-1774}, keywords = {LTER-MCM}, doi = {LTER}, author = {Osvaldo E. Sala and Kinzig, A and Leemans, R and Lodge, D and Mooney, H and Oesterheld, M and Poff, N and Sykes, M and Walker, B and Walkder, M and Diana H. Wall and F. S. Chapin and Armesto, J and Berlow, E and Bloomfield, J and Dirzo, R and Huber-Sanwald, E and Huenneke, L and Jackson, R} } @inbook {1449, title = {Arctic and Antarctic lakes: contrast or continuum?}, booktitle = {Poles Apart: A Study in Contrasts}, year = {1999}, pages = {59-68}, publisher = {University of Ottawa Press}, organization = {University of Ottawa Press}, keywords = {LTER-MCM, Biggie}, author = {Peter T. Doran and Peter Adams and Ecclestone, M} } @mastersthesis {1454, title = {Diatoms of the McMurdo Dry Valleys, Antarctica: A taxonomic appraisal including a detailed study of the genus Hantzschia.}, volume = {M.S.}, year = {1999}, school = {University of Michigan}, type = {masters}, address = {Ann Arbor, Michigan}, keywords = {LTER-MCM}, author = {Alexander S. Alger} } @article {1456, title = {Dry Valley streams in Antarctica: ecosystems waiting for water}, journal = {Bioscience}, volume = {49}, year = {1999}, pages = {985-995}, keywords = {LTER-MCM}, author = {Diane M. McKnight and Dev K. Niyogi and Alexander S. Alger and Bomblies, Arne and Peter A. Conovitz and Cathy M. Tate} } @article {1457, title = {Effects of research diving on a stratified antarctic lake}, journal = {Water Research}, year = {1999}, keywords = {LTER-MCM}, author = {Kepner, R.L. and A. Kortyna and Robert A. Wharton Jr. and Peter T. Doran and Dale T. Andersen and Emily C. Roberts} } @article {1459, title = {Geomicrobiology of sub-glacial ice above Vostok Station}, journal = {Science}, volume = {286}, year = {1999}, pages = {2141-2144}, keywords = {LTER-MCM}, doi = {10.1126/science.286.5447.2141}, author = {John C. Priscu and Edward E. Adams and W. Berry Lyons and Mary A. Voytek and David W. Mogk and Robert L. Brown and Christopher P. McKay and Cristina D. Takacs-Vesbach and Kathleen A. Welch and Craig F. Wolf and Julie D. Kirshtein and Recep Avci} } @article {1481, title = {Analysis of transient storage subject to unsteady flow: diel flow variation in an Antarctic stream}, journal = {Journal of the North American Benthological Society}, volume = {17}, year = {1998}, month = {06/1998}, pages = {143-154}, keywords = {LTER-MCM}, url = {http://www.jstor.org/stable/1467958}, author = {Robert L. Runkel and Diane M. McKnight and Edmund D. Andrews} } @article {1493, title = {Dissolved gases in perennially ice-covered lakes of the McMurdo Dry Valleys, Antarctica}, journal = {Antarctic Science}, volume = {10}, year = {1998}, pages = {124-133}, keywords = {LTER-MCM}, author = {Dale T. Andersen and Christopher P. McKay and Robert A. Wharton Jr.} } @article {1504, title = {Longitudinal Patterns in Algal Abundance and Species Distribution in Meltwater Streams in Taylor Valley, Southern Victoria Land, Antarctica, in Ecosystem Processes in a Polar Desert: The McMurdo Dry Valleys, Antarctica}, journal = {Antarctic Research Series}, volume = {72}, year = {1998}, pages = {109-127}, keywords = {LTER-MCM}, author = {Diane M. McKnight and Alexander S. Alger and Cathy M. Tate and Gordon H Shupe and Sarah A. Spaulding} } @article {1482, title = {Perennial Antarctic Lake Ice: An Oasis for Life in a Polar Desert}, journal = {Science}, volume = {280}, year = {1998}, month = {06/1998}, pages = {2095-2098}, type = {Journal}, keywords = {LTER-MCM, Biggie}, doi = {10.1126/science.280.5372.2095}, url = {http://www.sciencemag.org/content/280/5372/2095.short}, author = {John C. Priscu and Christian H. Fritsen and Edward E. Adams and Stephen J. Giovannoni and Hans W. Paerl and Christopher P. McKay and Peter T. Doran and Douglas A. Gordon and Brian D. Lanoil and James L. Pinckney} } @inbook {1521, title = {Permanent Ice Covers of the McMurdo Dry Valley Lakes, Antarctica: Bubble Formation and Metamorphism}, booktitle = {Ecosystem Processes in a Polar Desert: The McMurdo Dry Valleys, Antarctica}, series = {Antarctic Research Series}, volume = {72}, year = {1998}, pages = {281-295}, keywords = {LTER-MCM}, author = {Edward E. Adams and John C. Priscu and Christian H. Fritsen and Scott R.Smith and Steven L. Brackman} } @inbook {1522, title = {Permanent Ice Covers of the McMurdo Dry Valleys Lakes, Antarctica: Liquid Water Contents}, booktitle = {Ecosystem Processes in a Polar Desert: The McMurdo Dry Valleys, Antarctica}, series = {Antarctic Research Series}, volume = {72}, year = {1998}, pages = {269-280}, keywords = {LTER-MCM}, author = {Christian H. Fritsen and Edward E. Adams and Christopher P. McKay and John C. Priscu} } @inbook {1554, title = {Ecological processes in a cold desert ecosystem: the abundance and species distribution of algal mats in glacial meltwater streams in Taylor Valley}, booktitle = {Institute of Arctic and Alpine Research}, series = {Occasional Paper}, volume = {51}, year = {1997}, pages = {108 pp}, publisher = {University of Colorado}, organization = {University of Colorado}, keywords = {LTER-MCM}, url = {http://instaar.colorado.edu/other/download/OP51-ECOLOGICAL-PROCESSES.pdf}, author = {Alexander S. Alger and Diane M. McKnight and Sarah A. Spaulding and Cathy M. Tate}, editor = {Gordon H Shupe and Kathleen A. Welch and R. L. Edwards and Edmund D. Andrews} } @inbook {1564, title = {Species composition and primary production of algal communities in Dry Valley streams in Antarctica: Examination of the functional role of biodiversity}, booktitle = {Ecosystem Processes in Antarctic Ice-free Landscapes}, year = {1997}, pages = {171-179}, publisher = {Balkema Press, Rotterdam}, organization = {Balkema Press, Rotterdam}, keywords = {LTER-MCM}, author = {Dev K. Niyogi and Cathy M. Tate and Diane M. McKnight and John H. Duff and Alexander S. Alger} } @article {1574, title = {Geochemistry of aquatic humic substances in the Lake Fryxell Basin, Antarctica}, journal = {Biogeochemistry}, volume = {34}, year = {1996}, pages = {157-188}, keywords = {LTER-MCM}, author = {George R. Aiken and Diane M. McKnight and Richard A. Harnish and Robert Wershaw} } @article {1580, title = {Reflectance spectroscopy and geochemical analyses of Lake Hoare sediments, Antarctica: Implications for remote sensing of the Earth and Mars}, journal = {Geochimica et Cosmochimica Acta}, volume = {60}, year = {1996}, pages = {765-785}, keywords = {LTER-MCM}, author = {Bishop, Janice L. and Koeberl, C and C. Kralik and H. Froschl}, editor = {P.A.J. Englert and Dale T. Andersen and C.M. Pieters and Robert A. Wharton Jr.} } @article {1594, title = {McMurdo LTER: Species composition and spatial distribution of algal mats in Green Creek, Taylor Valley, Antarctica}, journal = {Antarctic Journal of the U. S.}, volume = {30}, year = {1995}, pages = {289-291}, keywords = {LTER-MCM}, author = {Alexander S. Alger and Sarah A. Spaulding and Gordon H Shupe and Diane M. McKnight} } @article {1604, title = {Some metamorphic processes in the lake ice of the McMurdo Dry Valleys}, journal = {Antarctic Journal of the U.S.}, volume = {30}, year = {1995}, pages = {307-309}, keywords = {LTER-MCM}, author = {Edward E. Adams and John C. Priscu and Atsushi Sato} } @article {1606, title = {Streamflow, water-temperature, and specific-conductance data for selected streams draining into Lake Fryxell, Lower Taylor Valley, Victoria Land, Antarctica, 1990-92}, journal = {U.S. Geological Survey. Open-File Report 94-545}, year = {1995}, keywords = {LTER-MCM}, author = {Paul Von Guerard and Diane M. McKnight and Richard A. Harnish and J. W. Gartner and Edmund D. Andrews} } @article {1611, title = {Aquatic fulvic acids in algal-rich antarctic ponds}, journal = {Limnology and Oceanography}, volume = {39}, year = {1994}, month = {07/1994}, pages = {1972-1979}, keywords = {LTER-MCM, Biggie}, author = {Diane M. McKnight and Edmund D. Andrews and Sarah A. Spaulding and George R. Aiken} } @article {1612, title = {Light transmission and reflection in perennially ice-covered Lake Hoare, Antarctica}, journal = {Journal Geophysics Research}, volume = {99}, year = {1994}, month = {06/1994}, pages = {20427-20444}, keywords = {LTER-MCM}, doi = {10.1029/94JC01414}, author = {Christopher P. McKay and Gary D. Clow and Dale T. Andersen and Robert A. Wharton Jr.} } @article {1632, title = {Dissolved Organic Material in Dry Valley Lakes: A Comparison of Lake Fryxell, Lake Hoare, and Lake Vanda, in Physical and Biogeochemical Processes in Antarctic Lakes}, journal = {Antarctic Research Series}, volume = {59}, year = {1993}, pages = {119-133}, keywords = {LTER-MCM}, author = {Diane M. McKnight and George R. Aiken and Edmund D. Andrews and E. C. Bowles and Richard A. Harnish} } @article {1642, title = {Perennial ice covers and their influence on antarctic lake ecosystems, in Physical and Biogeochemical Processes in Antarctic Lakes}, journal = {Antarctic Research Series}, volume = {59}, year = {1993}, pages = {53-70}, keywords = {LTER-MCM}, author = {Robert A. Wharton Jr. and Christopher P. McKay and Gary D. Clow and Dale T. Andersen} } @article {1644, title = {Potential hydrologic and geochemical consequences of the 1992 merging of Lake Chad with Lake Hoare in Taylor Valley}, journal = {Antarctic Journal of the U.S.}, volume = {28}, year = {1993}, pages = {249-251}, keywords = {LTER-MCM}, author = {Diane M. McKnight and Edmund D. Andrews} } @inbook {1646, title = {Terrigenous clastic sedimentation in antarctic dry valley lakes}, booktitle = {Physical and Biogeochemical Processes in Antarctic Lakes}, series = {Antarctic Research Series}, volume = {59}, year = {1993}, pages = {71-81}, publisher = {Wiley}, organization = {Wiley}, keywords = {LTER-MCM}, isbn = {9780875908304}, doi = {10.1029/AR059p0071}, author = {David W. Andersen and Robert A. Wharton Jr. and Steven W. Squyres} }