@article {4997, title = {Permanent stress adaptation and unexpected high light tolerance in the shade-adapted Chlamydomonas priscui}, journal = {Plants}, volume = {13}, year = {2024}, month = {08/2024}, pages = {2254}, abstract = {

The Antarctic photopsychrophile, Chlamydomonas priscui UWO241, is adapted to extreme environmental conditions, including permanent low temperatures, high salt, and shade. During long-term exposure to this extreme habitat, UWO241 appears to have lost several short-term mechanisms in favor of constitutive protection against environmental stress. This study investigated the physiological and growth responses of UWO241 to high-light conditions, evaluating the impacts of long-term acclimation to high light, low temperature, and high salinity on its ability to manage short-term photoinhibition. We found that UWO241 significantly increased its growth rate and photosynthetic activity at growth irradiances far exceeding native light conditions. Furthermore, UWO241 exhibited robust protection against short-term photoinhibition, particularly in photosystem I. Lastly, pre-acclimation to high light or low temperatures, but not high salinity, enhanced photoinhibition tolerance. These findings extend our understanding of stress tolerance in extremophilic algae. In the past 2 decades, climate change-related increasing glacial stream flow has perturbed long-term stable conditions, which has been associated with lake level rise, the thinning of ice covers, and the expansion of ice-free perimeters, leading to perturbations in light and salinity conditions. Our findings have implications for phytoplankton survival and the response to change scenarios in the light-limited environment of Antarctic ice-covered lakes.

}, keywords = {LTER-MCM, Cyclic electron flow, environmental change, extremophile, photo-acclimation, photoinhibition}, doi = {10.3390/plants13162254}, url = {https://www.mdpi.com/2223-7747/13/16/2254}, author = {Popson, Devon and D{\textquoteright}Silva, Susanna and Wheeless, Kaylie and Rachael M. Morgan-Kiss} } @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 {4758, title = {Patterns of interdisciplinary collaboration resemble biogeochemical relationships in the McMurdo Dry Valleys, Antarctica: A historical social network analysis of science, 1907{\textendash}2016}, journal = {Polar Research}, volume = {41}, year = {2022}, month = {04/2022}, pages = {8037}, abstract = {

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

}, keywords = {LTER-MCM, critical physical geography, environmental history, history of science, science and technology studies, scientometrics, visual network analysis}, doi = {10.33265/polar.v41.8037}, url = {https://polarresearch.net/index.php/polar/article/view/8037}, author = {Chignell, Stephen M. and Howkins, Adrian and Gullett, Poppie and Andrew G Fountain} } @article {4716, title = {Photosynthetic adaptation to polar life: Energy balance, photoprotection and genetic redundancy}, journal = {Journal of Plant Physiology}, volume = {268}, year = {2022}, month = {01/2022}, pages = {153557}, abstract = {

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

}, keywords = {LTER-MCM, genomic redundancy, light, photoprotection, photopsychrophily, photopsychrotolerance, Photosynthesis, temperature}, doi = {10.1016/j.jplph.2021.153557}, url = {https://www.sciencedirect.com/science/article/pii/S0176161721001966}, author = {H{\"u}ner, Norman P. A. and Smith, David R. and Cvetkovska, Marina and Zhang, Xi and Alexander G. Ivanov and Szyszka-Mroz, Beth and Kalra, Isha and Rachael M. Morgan-Kiss} } @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 {4734, title = {Phagotrophic protists (protozoa) in Antarctic terrestrial ecosystems: Diversity, distribution, ecology, and best research practices}, journal = {Polar Biology}, volume = {44}, year = {2021}, month = {08/2021}, pages = {1467-1484}, abstract = {

Phagotrophic protists (formerly protozoa) are a highly diverse, polyphyletic grouping of generally unicellular, heterotrophic eukaryotes that are key regulators of the soil microbiome. The biodiversity and ecology of soil phagotrophic protists are still largely uncharacterized, especially in the Antarctic, which possesses some of the harshest terrestrial environments known and potentially many physiologically unique and scientifically interesting species. Antarctic soil systems are also highly limited in terms of moisture, temperature, and carbon, and the resulting reduced biological complexity can facilitate fine-tuned investigation of the drivers and functioning of microbial communities. To facilitate and encourage future research into protist biodiversity and ecology, especially in context of the broader functioning of Antarctic terrestrial communities, I review the biodiversity, distribution, and ecology of Antarctic soil phagotrophic protists. Biodiversity appears to be highly structured by region and taxonomic group, with the Antarctic Peninsula having the highest taxonomic diversity and ciliates (Ciliophora) being the most diverse taxonomic group. However, richness estimates are likely skewed by disproportionate sampling (over half of the studies are from the peninsula), habitat type bias (predominately moss-associated soils), investigator bias (toward ciliates and the testate amoeba morphogroup), and methodological approach (toward cultivation and morphological identification). To remedy these biases, a standardized methodology using both morphological and molecular identification and increased emphasis on microflagellate and naked amoeba morphogroups is needed. Additionally, future research should transition away from biodiversity survey studies to dedicated ecological studies that emphasize the function, ecophysiology, endemicity, dispersal, and impact of abiotic drivers beyond moisture and temperature.

}, keywords = {LTER-MCM, abiotic drivers of protist communities, Antarctic protozoa, Corythion dubium, phagotrophic soil protists, protist diversity}, issn = {0722-4060}, doi = {10.1007/s00300-021-02896-3}, url = {https://link.springer.com/article/10.1007/s00300-021-02896-3}, author = {Thompson, Andrew R.} } @article {4410, title = {Picocyanobacterial cells in near-surface air above terrestrial and freshwater substrates in Greenland and Antarctica}, journal = {Environmental Microbiology Reports}, year = {2020}, month = {03/2020}, abstract = {

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

}, keywords = {LTER-MCM}, doi = {10.1111/1758-2229.12832}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/1758-2229.12832}, author = {Trout-Haney, Jessica V. and Heindel, Ruth C and Ross A. Virginia} } @inbook {4333, title = {Placing the past: The McMurdo Dry Valleys and the problem of geographical specificity in Antarctic history}, booktitle = {Anthropocene Antarctica: Perspectives from the Humanities, Law and Social Sciences}, year = {2019}, publisher = {Routledge}, organization = {Routledge}, edition = {1st}, chapter = {11}, address = {London}, abstract = {

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

}, keywords = {LTER-MCM}, issn = {9780429429705}, doi = {10.4324/9780429429705}, url = {https://www.taylorfrancis.com/books/e/9780429429705}, author = {Howkins, Adrian} } @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 {4151, title = {Prediction of ice-free conditions for a perennially ice-covered Antarctic lake}, journal = {Journal of Geophysical Research: Earth Surface}, volume = {124}, year = {2019}, month = {02/2019}, abstract = {

Although perennially ice-covered Antarctic lakes have experienced variable ice thicknesses over the past several decades, future ice thickness trends and associated aquatic biological responses under projected global warming remain unknown. Heat stored in the water column in chemically stratified Antarctic lakes that have mid-depth temperature maxima, can significantly influence the ice thickness trends via upward heat flux to the ice/water interface. We modeled ice thickness of the west of lobe of Lake Bonney, Antarctica based on possible future climate scenarios utilizing a 1D thermodynamic model that accounts for surface radiative fluxes as well as the heat flux associated with the temperature evolution of the water column. Model results predict that the ice cover of Lake Bonney will shift from perennial to seasonal within one to four decades, a change that will drastically influence ecosystem processes within the lake.

}, keywords = {LTER-MCM}, doi = {10.1029/2018JF004756}, url = {https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018JF004756}, author = {Maciek K. Obryk and Peter T. Doran and John C. Priscu} } @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 {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 {4061, title = {The physical limnology of a permanently ice-covered and chemically stratified Antarctic lake using high resolution spatial data from an autonomous underwater vehicle}, journal = {Limnology and Oceanography}, volume = {63}, year = {2018}, month = {05/2018}, pages = {1234 - 1252}, abstract = {

We used an Environmentally Non-Disturbing Under-ice Robotic ANtarctic Explorer to make measurements of conductivity and temperature in Lake Bonney, a chemically stratified, permanently ice-covered Antarctic lake that abuts Taylor Glacier, an outlet glacier from the Polar Plateau. The lake is divided into two lobes \– East Lobe Bonney (ELB) and West Lobe Bonney (WLB), each with unique temperature and salinity profiles. Most of our data were collected in November 2009 from WLB to examine the influence of the Taylor Glacier on the structure of the water column. Temperatures adjacent to the glacier face between 20 m and 22 m were 38C colder than in the rest of WLB, due to latent heat transfer associated with melting of the submerged glacier face and inflow of cold brines that originate beneath the glacier. Melting of the glacier face into the salinity gradient below the chemocline generates a series of nearly horizontal intrusions into WLB that were previously documented in profiles measured with 3 cm vertical resolution in 1990\–1991. WLB and ELB are connected by a narrow channel through which water can be exchanged over a shallow sill that controls the position of the chemocline in WLB. A complex exchange flow appears to exist through the narrows, driven by horizontal density gradients and melting at the glacier face. Superimposed on the exchange is a net west- to-east flow generated by the higher volume of meltwater inflows to WLB. Both of these processes can be expected to be enhanced in the future as more meltwater is produced.\ 

}, keywords = {LTER-MCM}, doi = {10.1002/lno.10768}, url = {http://onlinelibrary.wiley.com/wol1/doi/10.1002/lno.10768/full}, author = {Spigel, Robert H. and John C. Priscu and Maciek K. Obryk and Stone, William C. and Peter T. Doran} } @inbook {4113, title = {Physiological and Biochemical Adaptations of Psychrophiles}, booktitle = {Extremophiles}, year = {2018}, publisher = {CRC Press}, organization = {CRC Press}, chapter = {9}, address = {Boca Raton}, abstract = {

The cold biosphere encompasses many microorganism-dominated habitats that rely on light-dependent primary production. Within these environments, there are numerous physical and chemical factors limiting metabolism and growth that the microorganisms must overcome. The psychrophilic microorganisms discussed herein integrate a complex spectrum of adaptive strategies to survive these physiological challenges, including genome evolution, enzyme structure and catalysis rate changes, cryoprotectant formation, and a multitude of photosynthetic adaptations. Psychrophilic organisms also hold the key to biotechnical advances and the future, such that psychrophilic enzymes are used for everything from laboratory reagents and industrial work to medical research and environmental sustainability. Researchers have learned to exploit psychrophiles\’ efficiency at low temperatures (i.e., cooler washing machines and energy-saving, cost-effective enzyme production), their higher energy activity (thus allowing lower concentrations of needed catalysts, reducing costs and procedure time), and their ability to contribute to hydrocarbon bioremediation. Although psychrophilic microbes exist in numerous habitats and undergo various adaptive strategies, an understanding of what makes an organism psychrophilic is still unknown in a large majority of cold-adapted organisms, and thus future investigations are needed regarding cold adaptation and their biotechnological potential. Even as research has increased over the last decade, new technological advances and high-throughput DNA sequencing will continue to provide information about cold adaptation or the mechanisms needed for survival in a changing world.

}, keywords = {LTER-MCM}, url = {https://www.taylorfrancis.com/books/e/9781498774932/chapters/10.1201\%2F9781315154695-9}, author = {Teufel, Amber G. and Rachael M. Morgan-Kiss} } @article {4021, title = {Primary productivity as a control over soil microbial diversity along environmental gradients in a polar desert ecosystem}, journal = {PeerJ}, volume = {5}, year = {2017}, month = {07/2017}, pages = {e3377}, abstract = {

Primary production is the fundamental source of energy to foodwebs and ecosystems, and is thus an important constraint on soil communities. This coupling is particularly evident in polar terrestrial ecosystems where biological diversity and activity is tightly constrained by edaphic gradients of productivity (e.g., soil moisture, organic carbon availability) and geochemical severity (e.g., pH, electrical conductivity). In the McMurdo Dry Valleys of Antarctica, environmental gradients determine numerous properties of soil communities and yet relatively few estimates of gross or net primary productivity (GPP, NPP) exist for this region. Here we describe a survey utilizing pulse amplitude modulation (PAM) fluorometry to estimate rates of GPP across a broad environmental gradient along with belowground microbial diversity and decomposition. PAM estimates of GPP ranged from an average of 0.27 mmol O2/m2/s in the most arid soils to an average of 6.97 mmol O2/m2/s in the most productive soils, the latter equivalent to 217 g C/m2/y in annual NPP assuming a 60 day growing season. A diversity index of four carbon-acquiring enzyme activities also increased with soil productivity, suggesting that the diversity of organic substrates in mesic environments may be an additional driver of microbial diversity. Overall, soil productivity was a stronger predictor of microbial diversity and enzymatic activity than any estimate of geochemical severity. These results highlight the fundamental role of environmental gradients to control community diversity and the dynamics of ecosystem-scale carbon pools in arid systems.\ 

}, keywords = {LTER-MCM}, doi = {10.7717/peerj.3377}, url = {https://peerj.com/articles/3377/}, author = {Kevin M. Geyer and Cristina D. Takacs-Vesbach and Michael N. Gooseff and John E. Barrett} } @article {3958, title = {Patterns of bacterial biodiversity in the glacial meltwater streams of the McMurdo Dry Valleys, Antarctica}, journal = {FEMS Microbiology Ecology}, volume = {92}, year = {2016}, month = {08/2016}, pages = {fiw148}, abstract = {

Microbial consortia dominate glacial meltwater streams from polar regions, including the McMurdo Dry Valleys (MDV), where they thrive under physiologically stressful conditions. In this study, we examined microbial mat types and sediments found in 12 hydrologically diverse streams to describe the community diversity and composition within and across sites. Sequencing of the 16S rRNA gene from 129 samples revealed \∼24 000 operational taxonomic units (\<97\% DNA similarity), making streams the most biodiverse habitat in the MDV. Principal coordinate analyses revealed significant but weak clustering by mat type across all streams (ANOSIM R-statistic = 0.28) but stronger clustering within streams (ANOSIM R-statistic from 0.28 to 0.94). Significant relationships (P \< 0.05) were found between bacterial diversity and mat ash-free dry mass, suggesting that diversity is related to the hydrologic regimes of the various streams, which are predictive of mat biomass. However, correlations between stream chemistry and community members were weak, possibly reflecting the importance of internal processes and hydrologic conditions. Collectively, these results suggest that localized conditions dictate bacterial community composition of the same mat types and sediments from different streams, and while MDV streams are hotspots of biodiversity in an otherwise depauperate landscape, controls on community structure are complex and site specific.

}, keywords = {LTER-MCM}, doi = {10.1093/femsec/fiw148}, url = {http://femsec.oxfordjournals.org/lookup/doi/10.1093/femsec/fiw148}, author = {David J. Van Horn and Wolf, Caitlin R. and Colman, Daniel R. and Jiang, Xiaoben and Tyler J. Kohler and Diane M. McKnight and Lee F. Stanish and Yazzie, Terrill and Cristina D. Takacs-Vesbach} } @article {3718, title = {Patterns of hydrologic connectivity in the McMurdo dry valleys, Antarctica: a synthesis of 20 years of hydrologic data}, journal = {Hydrological Processes}, volume = {30}, year = {2016}, month = {04/2016}, pages = {2958-2975}, chapter = {2958}, abstract = {

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

}, keywords = {LTER-MCM}, doi = {10.1002/hyp.10818}, url = {http://onlinelibrary.wiley.com/doi/10.1002/hyp.10818}, author = {Wlostowski, Adam and Michael N. Gooseff and Diane M. McKnight and Chris Jaros and W. Berry Lyons} } @article {1061, title = {Photoadaptation to the polar night by phytoplankton in a permanently ice-covered Antarctic lake}, journal = {Limnology and Oceanography}, volume = {61}, year = {2016}, month = {05/2015}, abstract = {

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

}, keywords = {LTER-MCM}, doi = {10.1002/lno.10107}, url = {https://aslopubs.onlinelibrary.wiley.com/doi/full/10.1002/lno.10107}, author = {Rachael M. Morgan-Kiss and Michael P. Lizotte and Weidong Kong and John C. Priscu} } @mastersthesis {4088, title = {Physiological characteristics of fungi associated with Antarctic environments}, volume = {M.S.}, year = {2016}, school = {Montana State University}, type = {masters}, address = {Bozeman, MT}, abstract = {

The permanent ice covers on the lakes of Antarctica\&$\#$39;s McMurdo Dry Valleys region harbor a diverse group of phototrophic and heterotrophic microorganisms that metabolize during the short summer months when solar radiation produces melt inclusions within the ice and provides energy to drive photosynthesis. Laboratory cultures of fungi were obtained from ice cores taken from Lakes Bonney (east lobe) and Chad, and sediments collected from Subglacial Lake Whillans (West Antarctica). Using molecular techniques, the internal transcribed spacer (ITS) region of the ribosomal DNA (rDNA) was sequenced to identify fungal types and to determine whether they may be unique to this region. Four axenic fungal cultures, Tetracladium ellipsoideum, Lecythophora hoffmannii, Mucor sp., and an unidentified Ascomycota were successfully isolated. These isolates are closely related to organisms that have been previously reported in Antarctica and other cold habitats. The isolates were tested for growth characteristics under various temperature and nutrient regimes. Temperature response experiments revealed that all the isolated fungi were psychrotolerant and growth rates were greatest at 25\°C. Of major significance in evaluating the potential of Antarctic fungi as a bioresource is their ability to produce bioactive compounds. Two out of four isolated organisms exhibited antimicrobial activity against several plant pathogens. The metabolic potential and preferred substrate utilization was examined by exposing fungal isolates to a variety of substrates in a 96 well \"Biolog\" plate. A strong correlation was found among substrate utilization, isolates, temperature and the different carbon substrates. This experiment revealed that the isolated fungi have preferences for different labile carbon substrates at 4\°C and 24\°C which may imply different physiologies at different times of year in the lake ice-covers. Results from my studies will help understand the role of fungi in lake ice and subglacial lake sediment ecosystems, and the physiology of fungi living in cold environments.

}, keywords = {LTER-MCM}, url = {https://scholarworks.montana.edu/xmlui/handle/1/9835}, author = {Kudalkar, Priyanka S. and John C. Priscu} } @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 {3205, title = {Patterns and processes of salt efflorescences in the McMurdo region, Antarctica}, journal = {Artic, Antarctic and Alpine Research}, year = {2015}, abstract = {

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

}, keywords = {LTER-MCM}, url = {http://aaarjournal.org/doi/abs/10.1657/AAAR0014-024}, author = {Bisson, K. M. and Kathleen A. Welch and Sue Welch and Sheets, J. M. and W. Berry Lyons and Joseph S. Levy and Andrew G Fountain} } @phdthesis {4087, title = {Physical and chemical controls on the abundance and composition of stream microbial mats from the McMurdo Dry Valleys, Antarctica}, volume = {Ph.D.}, year = {2015}, pages = {272}, school = {University of Colorado}, type = {doctoral}, address = {Boulder, CO}, abstract = {

The McMurdo Dry Valleys of Antarctica are a cold, dry desert, yet perennial microbial mats are abundant in the ephemeral glacial meltwater streams that flow during austral summers. Three types of mats are present (orange, black, and green), and are primarily comprised of filamentous cyanobacteria,\ Nostoc, and chlorophytes, respectively. Mat types furthermore occupy distinct habitats within streams, utilizing the benthos, hyporheic zone, and water column, which expose them to different environmental conditions. Due to a lack of lateral inflows, allochthonous organic inputs, and negligible grazing activity, these streams are ideal for the controlled ecological study of microbial mats. Here, I investigated how mats will respond to physical disturbance, alterations in the hydrologic regime, and nutrient liberation from permafrost melt in the future. Specifically, I: 1) quantified and characterized the regrowth of mat biomass, community structure, and elemental stoichiometry after a scouring disturbance, 2) investigated how geomorphology and taxonomic identity influences the response of mat biomass to hydrologic regime in transects monitored over two decades, and 3) evaluated relationships between water chemistry and the elemental and isotopic composition of mat types over longitudinal and valley-wide gradients in Taylor Valley. I found that mats recovered ~20-50\% of their biomass over the course of an austral summer following scour. Algal communities were significantly different in composition between disturbed and control treatments, but all samples naturally varied in species and elemental stoichiometry over the study period. When the long- term record of mat biomass was compared with hydrologic variables, stream channel mats (orange and green) had the greatest correlations, while marginal mats (black) showed weaker relationships with flow regime. Relationships also differed as a function of stream geomorphology, indicating the importance of substrata and gradient in conjunction with discharge. Lastly, mats showed unique elemental and isotopic compositions. Green and orange mats within the stream channel most reflected water column nutrient concentrations, while black mats showed significant nitrogen fixation. These results highlight the importance of taxonomic identity and habitat to modeling primary production here and elsewhere, and provide insight to how stream microbial mat communities are formed, maintained, and ultimately persist in an isolated polar desert.

}, keywords = {LTER-MCM, algae, Antarctica, biological sciences, climate change, Disturbance, earth sciences, McMurdo Dry Valleys, microbial mats}, url = {https://search.proquest.com/docview/1690497718?accountid=14503}, author = {Tyler J. Kohler}, editor = {Diane M. McKnight} } @book {3305, title = {The Polar Regions: An Environmental History}, year = {2015}, pages = {248}, publisher = {Polity}, organization = {Polity}, address = {Cambridge}, abstract = {

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

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

}, keywords = {LTER-MCM}, isbn = {978-0-7456-7080-5}, url = {http://www.wiley.com/WileyCDA/WileyTitle/productCd-0745670806.html}, author = {Howkins, Adrian} } @article {3712, title = {Potential for real-time understanding of coupled hydrologic and biogeochemical processes in stream ecosystems: Future integration of telemetered data with process models for glacial meltwater streams}, journal = {Water Resources Research}, volume = {51}, year = {2015}, month = {08/2015}, pages = {6725 - 6738}, keywords = {LTER-MCM}, doi = {10.1002/2015WR017618}, url = {http://doi.wiley.com/10.1002/2015WR017618http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002\%2F2015WR017618}, author = {Diane M. McKnight and Cozzetto, K and Cullis, James D.S. and Michael N. Gooseff and Chris Jaros and Koch, J. and W. Berry Lyons and Neupauer, R. M. and Wlostowski, Adam} } @article {3189, title = {Pressure-driven, shoreline currents in a perennially ice-covered, pro-glacial lake in Antarctica, identified from a LiCl tracer injected into a pro-glacial stream}, journal = {Hydrological Processes}, volume = {29}, year = {2015}, month = {05-2015}, pages = {2212 - 2231}, abstract = {

The distribution of streamwater within ice-covered lakes influences sub-ice currents, biological activity and shoreline morphology. Perennially ice-covered lakes in the McMurdo Dry Valleys, Antarctica, provide an excellent natural laboratory to study hydrologic\–limnologic interactions under ice cover. For a 2\ h period on 17 December 2012, we injected a lithium chloride tracer into Andersen Creek, a pro-glacial stream flowing into Lake Hoare. Over 4\ h, we collected 182 water samples from five stream sites and 15 ice boreholes. Geochemical data showed that interflow travelled West of the stream mouth along the shoreline and did not flow towards the lake interior. The chemistry of water from Andersen Creek was similar to the chemistry of water below shoreline ice. Additional evidence for Westward flow included the morphology of channels on the ice surface, the orientation of ripple marks in lake sediments at the stream mouth and equivalent temperatures between Andersen Creek and water below shoreline ice. Streamwater deflected to the right of the mouth of the stream, in the opposite direction predicted by the Coriolis force. Deflection of interflow was probably caused by the diurnal addition of glacial runoff and stream discharge to the Eastern edge of the lake, which created a strong pressure gradient sloping to the West. This flow directed stream momentum away from the lake interior, minimizing the impact of stream momentum on sub-ice currents. It also transported dissolved nutrients and suspended sediments to the shoreline region instead of the lake interior, potentially affecting biological productivity and bedform development.

}, keywords = {LTER-MCM}, doi = {10.1002/hyp.v29.910.1002/hyp.10352}, url = {http://doi.wiley.com/10.1002/hyp.v29.9http://doi.wiley.com/10.1002/hyp.10352}, author = {Castendyk, Devin and Diane M. McKnight and Kathleen A. Welch and Niebuhr, Spencer and Chris Jaros} } @article {3212, title = {The permanent ice cover of Lake Bonney, Antarctica: The influence of thickness and sediment distribution on photosynthetically available radiation and chlorophyll-a distribution in the underlying water column}, journal = {Journal of Geophysical Research: Biogeosciences}, volume = {119}, year = {2014}, month = {09/2014}, pages = {1879 - 1891}, chapter = {1879}, abstract = {

The thick permanent ice cover on the lakes of the McMurdo Dry Valleys, Antarctica, inhibits spatial lake sampling due to logistical constraints of penetrating the ice cover. To date most sampling of these lakes has been made at only a few sites with the assumption that there is a spatial homogeneity of the physical and biogeochemical properties of the ice cover and the water column at any given depth. To test this underlying assumption, an autonomous underwater vehicle (AUV) was deployed in Lake Bonney, Taylor Valley. Measurements were obtained over the course of 2 years in a 100 \× 100 m horizontal sampling grid (at a 0.2\ m vertical resolution). Additionally, the AUV measured the ice thickness (in water equivalent) and collected images looking up through the ice, which were used to quantify sediment distribution on the surface and within the ice. Satellite imagery was used to map sediment distribution on the surface of the ice. We present results of the spatial investigation of the sediment distribution on the ice cover and its effects on biological processes, with particular emphasis on photosynthetically active radiation (PAR). The surface sediment is a secondary controller of the ice cover thickness, which in turn controls the depth-integrated PAR in the water column. Our data revealed that depth-integrated PAR was negatively correlated with depth-integrated chlorophyll-a (r\ =\ 0.88,\ p\ \<\ 0.001,\ n\ =\ 83), which appears to be related to short-term photoadaptation of phytoplanktonic communities to spatial and temporal variation in PAR within the water column.

}, keywords = {LTER-MCM}, doi = {10.1002/2014JG002672}, url = {http://doi.wiley.com/10.1002/2014JG002672}, author = {Maciek K. Obryk and Peter T. Doran and John C. Priscu} } @article {3525, title = {Polar and alpine microbiology in a changing world}, journal = {FEMS Microbiology Ecology}, volume = {89}, year = {2014}, month = {08/2014}, pages = {209 - 210}, chapter = {209}, keywords = {LTER-MCM}, doi = {10.1111/fem.2014.89.issue-210.1111/1574-6941.12371}, url = {http://onlinelibrary.wiley.com/doi/10.1111/1574-6941.12371/abstract}, author = {John C. Priscu and Johanna Laybourn-Parry and H{\"a}ggblom, Max} } @article {1081, title = {Physicochemical and biological dynamics in a coastal Antarctic lake as it transitions from frozen to open water}, journal = {Antarctic Science}, volume = {25}, year = {2013}, month = {12/2013}, pages = {663{\textendash}675}, keywords = {LTER-MCM}, author = {Markus Dieser and Christine M. Foreman and Chris Jaros and John T. Lisle and Mark C. Greenwood and Johanna Laybourn-Parry and Penney L. Miller and Yu-Ping Chin and Diane M. McKnight} } @article {1107, title = {Perchlorate and chlorate biogeochemistry in ice-covered lakes of the McMurdo Dry Valleys, Antarctica}, journal = {Geochimica et Cosmochimica Acta}, volume = {98}, year = {2012}, month = {12/2012}, pages = {19 - 30}, keywords = {LTER-MCM}, doi = {10.1016/j.gca.2012.09.014}, url = {http://www.sciencedirect.com/science/article/pii/S001670371200511X}, author = {W. Andrew Jackson and Alfonso F. Davila and Nubia Estrada and W. Berry Lyons and John D. Coates and John C. Priscu} } @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 {1125, title = {Protist diversity in a permanently ice-covered Antarctic Lake during the polar night transition}, journal = {The ISME Journal}, volume = {5}, year = {2011}, month = {9/2011}, pages = {1559 - 1564}, keywords = {LTER-MCM}, doi = {10.1038/ismej.2011.23}, url = {http://www.nature.com/ismej/journal/v5/n9/abs/ismej201123a.html}, author = {Scott Bielewicz and Elanor R. Bell and Weidong Kong and Iddo Friedberg and John C. Priscu and Rachael M. Morgan-Kiss} } @article {1158, title = {Palaeoenvironmental implications derived from a piston core from east lobe Bonney, Taylor Valley, Antarctica}, journal = {Antarctic Science}, volume = {22}, year = {2010}, month = {10/2010}, pages = {522 - 530}, keywords = {LTER-MCM}, doi = {10.1017/S0954102010000556}, author = {Wagner, Bernd and Ortlepp, Sabrina and Kenig, Fabien and Peter T. Doran and Melles, Martin} } @article {1174, title = {Physiochemical properties influencing biomass abundance and primary production in Lake Hoare, Antarctica}, journal = {Ecological Modelling}, year = {2010}, keywords = {LTER-MCM}, doi = {LTER}, author = {Herbei, Radu and W. Berry Lyons and Johanna Laybourn-Parry and Christopher B. Gardner and John C. Priscu and Diane M. McKnight} } @article {1191, title = {Particulate organic and dissolved inorganic carbon stable isotopic compositions in Taylor Valley lakes, Antarctica: the effect of legacy}, journal = {Hydrobiologia}, volume = {632}, year = {2009}, pages = {139-156}, keywords = {LTER-MCM}, doi = {LTER}, author = {Knoepfle, J and Peter T. Doran and Kenig, Fabien and W. Berry Lyons and Galchenko, V} } @article {1203, title = {Persistent effects of a discrete climate event on a polar desert ecosystem}, journal = {Global Change Biology}, volume = {14}, year = {2008}, month = {06/2008}, pages = {2249-2261}, type = {Journal}, keywords = {LTER-MCM, Climate Response, nematodes}, doi = {10.1111/j.1365-2486.2008.01641.x}, author = {John E. Barrett and Ross A. Virginia and Diana H. Wall} } @article {1221, title = {Plankton Dynamics in the McMurdo Dry Valley Lakes During the Transition to Polar Night - A Project Contributing to EBA}, journal = {SCAR EBA (Evolution and Biodiversity in the Antarctic) Newsletter, October 2008}, volume = {2}, year = {2008}, keywords = {LTER-MCM}, doi = {LTER}, author = {John C. Priscu} } @mastersthesis {1222, title = {Provenance of organic matter in Taylor Valley, Antarctica lakes: Scanning Electron Microscopy of sediment}, volume = {M.S.}, year = {2008}, school = {University of Illinois, Chicago}, type = {masters}, keywords = {LTER-MCM}, doi = {LTER}, author = {Jonathan P. Warnock} } @inbook {1273, title = {Pedogenic carbonate distribution within glacial till in Taylor Valley, Southern Victoria Land, Antarctica}, booktitle = {Paleoenvironmental Record and Applications of Calcretes and Palustrine Carbonates}, year = {2006}, pages = {89-103}, publisher = {Geological Society of America}, organization = {Geological Society of America}, keywords = {LTER-MCM}, doi = {10.1130/2006.2416(06)}, author = {Foley, K and W. Berry Lyons and John E. Barrett and Ross A. Virginia} } @article {1281, title = {Phosphorus fractions in soils of Taylor Valley, Antarctica}, journal = {Soil Science Society of America Journal}, volume = {70}, year = {2006}, pages = {806-815}, keywords = {LTER-MCM}, doi = {LTER}, author = {Blecker, S and Ippolito, J and John E. Barrett and Diana H. Wall and Ross A. Virginia and Norvell, K} } @mastersthesis {1316, title = {Pedogenic Carbonate Distribution within Glacial Till in Taylor Valley, Southern Victoria Land, Antarctica}, volume = {M.S.}, year = {2005}, school = {The Ohio State University}, type = {masters}, keywords = {LTER-MCM}, doi = {LTER}, author = {Foley, K} } @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} } @article {1305, title = {Perturbation of hydrochemical conditions in natural microcosms entombed within Antarctic ice}, journal = {Ice and Climate News}, volume = {6}, year = {2005}, pages = {22-23}, keywords = {LTER-MCM}, author = {Martyn Tranter and Andrew G Fountain and Christian H. Fritsen and W. Berry Lyons and John C. Priscu and Stratham, P and Kathleen A. Welch} } @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} } @article {1289, title = {Potential soil organic matter turnover in Taylor Valley, Antarctica}, journal = {Arctic, Antarctic, and Alpine Research}, volume = {37}, year = {2005}, month = {02/2005}, pages = {108-117}, type = {Journal}, abstract = {

Antarctic Dry Valley ecosystems are among the most inhospitable soil ecosystems on earth with simple food webs and nearly undetectable fluxes of carbon (C) and nitrogen (N). Due to the lack of vascular plants, soil organic matter concentrations are extremely low, and it is unclear how much of the contemporary soil C budget is actively cycling or a legacy of paleolake production and sedimentation. While recent work indicates multiple sources of organic matter for dry valley soils, the composition and kinetics of organic pools remain poorly characterized. We examined soil organic matter pools and potential C and N turnover in soils from within six sites located across three hydrological basins of Taylor Valley, Antarctica that differed in surface age, microclimate and proximity to legacy (paleolake) sources of organic matter. We estimated potential C and N mineralization, and rate kinetics using gas exchange and repeated leaching techniques during 90-d incubations of surface soils collected from valley basin and valley slope positions in three basins of Taylor Valley. Soil organic C content was negatively correlated with the ages of underlying tills, supporting previous descriptions of legacy organic matter. Carbon and N mineralization generally followed 1st order kinetics and were well described by exponential models. Labile pools of C (90 d) were 10\% of the total organic C in the upper 5 cm of the soil profile. Labile N was 50\% of the total N in surface soils of Taylor Valley. These results show that a large proportion of soil C and particularly N are mineralizable under suitable conditions and suggest that a kinetically defined labile pool of organic matter is potentially active in the field during brief intervals of favorable microclimate. Climate variation changing the duration of these conditions may have potentially large effects on the small pools of C and N in these soils.

}, keywords = {LTER-MCM, Biggie}, doi = {10.1657/1523-0430(2005)037[0108:PSOMTI]2.0.CO;2}, url = {http://instaar.metapress.com/content/e653225425230175/}, author = {John E. Barrett and Ross A. Virginia and Andrew N. Parsons and Diana H. Wall} } @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 {1340, title = {Paleolimnology of Ice-covered Environments}, booktitle = {Long-term environmental change in Arctic and Antarctic lakes}, year = {2004}, pages = {475-507}, publisher = {Kluwer Academic Publishers}, organization = {Kluwer Academic Publishers}, keywords = {LTER-MCM}, author = {Peter T. Doran and John C. Priscu and W. Berry Lyons and Powell, R and Robert J. Poreda}, editor = {Pienitz, R and Douglas, Marianne S. V. and John Smol} } @mastersthesis {1372, title = {Phosphorus in Taylor Valley, Antarctica: the connection between landscape age and nutrient limitation in aquatic ecosystem components}, volume = {M.S.}, year = {2003}, school = {The Ohio State University}, type = {masters}, keywords = {LTER-MCM}, doi = {LTER}, author = {Gudding, J} } @inbook {1373, title = {Polar Limnology - the past, the present, and the future. Review in the SCAR VIII International Biology Symposium Proceedings}, booktitle = {Antarctic Biology in a global context}, year = {2003}, keywords = {LTER-MCM}, author = {Johanna Laybourn-Parry} } @article {1394, title = {Population age structure of nematodes in the Antarctic Dry Valleys: perspectives on time, space, and habitat suitability}, journal = {Arctic,Antarctic, and Alpine Research}, volume = {34}, year = {2002}, pages = {159-168}, keywords = {LTER-MCM}, author = {Porazinska, D and Diana H. Wall and Ross A. Virginia} } @article {1397, title = {Phytoplankton phosphorus deficiency and alkaline phosphatase activity in the McMurdo Dry Valley lakes, Antarctica.}, journal = {Limnology and Oceanography}, volume = {46}, year = {2001}, month = {09/2001}, pages = {1331-1346}, type = {Journal}, keywords = {LTER-MCM}, author = {John E. Dore and John C. Priscu} } @article {1422, title = {Phytoplankton dynamics in a stably stratified Antarctic lake during winter darkness}, journal = {Journal of Phycology}, volume = {36}, year = {2000}, month = {10/2000}, pages = {852-861}, type = {Journal}, keywords = {LTER-MCM, Biggie, winter}, doi = {10.1046/j.1529-8817.2000.00031.x}, author = {Diane M. McKnight and B. L. Howes and C. D. Taylor and D. D. Goehringer} } @article {1443, title = {Protozoan growth rates in Antarctic lakes}, journal = {Polar Biology}, volume = {23}, year = {2000}, pages = {445-451}, keywords = {LTER-MCM}, author = {Johanna Laybourn-Parry and Elanor R. Bell and Emily C. Roberts} } @article {1447, title = {Physical controls on the Taylor Valley Ecosystem, Antarctica}, journal = {BioScience}, volume = {49}, year = {1999}, month = {12/1999}, pages = {961-972}, type = {Journal}, keywords = {LTER-MCM, Water availability}, author = {Andrew G Fountain and W. Berry Lyons and Melody B. Burkins and Gayle L. Dana and Peter T. Doran and Karen J. Lewis and Diane M. McKnight and Daryl L. Moorhead and Andrew N. Parsons and John C. Priscu and Diana H. Wall and Robert A. Wharton Jr. and Ross A. Virginia} } @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} } @article {1523, title = {Photosynthetic characteristics of cyanobacteria in permanent ice covers on lakes in the McMurdo Dry Valleys, Antarctica}, journal = {Antarctic Journal of the United States - 1996 Review Issue (NSF 98-28)}, volume = {31}, year = {1998}, pages = {216-218}, keywords = {LTER-MCM}, author = {Christian H. Fritsen and John C. Priscu} } @article {1524, title = {Physical Limnology of the McMurdo Dry Valleys Lakes, in Ecosystem Processes in a Polar Desert: The McMurdo Dry Valleys, Antarctica}, journal = {Antarctic Research Series}, volume = {72}, year = {1998}, pages = {153-187}, keywords = {LTER-MCM}, author = {Spigel, Robert H. and John C. Priscu} } @inbook {1525, title = {Pigment Analysis of the Distribution, Succession, and Fate of Phytoplankton in the McMurdo Dry Valley Lakes of Antarctica}, booktitle = {Ecosystem Processes in a Polar Desert: The McMurdo Dry Valleys, Antarctica}, series = {Antarctic Research Series}, volume = {72}, year = {1998}, pages = {229-239}, keywords = {LTER-MCM}, author = {Michael P. Lizotte and John C. Priscu} } @inbook {1526, title = {Primary Production Processes in Streams of the McMurdo Dry Valleys, Antarctica}, booktitle = {Ecosystem Processes in a Polar Desert: The McMurdo Dry Valleys, Antarctica}, series = {Antarctic Research Series}, volume = {72}, year = {1998}, pages = {129-140}, keywords = {LTER-MCM}, author = {Ian Hawes and Clive Howard-Williams} } @inbook {1527, title = {Protozooplankton and Microzooplankton Ecology in Lakes of the Dry Valleys, Southern Victoria Land}, booktitle = {Ecosystem Processes in a Polar Desert: The McMurdo Dry Valleys, Antarctica}, series = {Antarctic Research Series}, volume = {72}, year = {1998}, pages = {255-267}, keywords = {LTER-MCM}, author = {Mark R. James and Julie A. Hall and Johanna Laybourn-Parry} } @phdthesis {1577, title = {Paleolimnology of Perenially Ice-Covered Antarctic Oasis Lakes}, volume = {Ph.D.}, year = {1996}, school = {University of Nevada Reno}, type = {doctoral}, address = {Reno, NV}, keywords = {LTER-MCM}, author = {Peter T. Doran and Robert A. Wharton Jr.} } @article {1578, title = {Phytoplankton Dynamics in the Stratified Water Column of Lake Bonney, Antarctica. I. Biomass and Productivity During the Winter-Spring Transition}, journal = {Polar Biology}, volume = {16}, year = {1996}, pages = {155-162}, keywords = {LTER-MCM}, author = {Michael P. Lizotte and Thomas R. Sharp and John C. Priscu} } @article {1596, title = {Paleolakes on Mars}, journal = {Journal of Paleolimnology}, volume = {13}, year = {1995}, pages = {267-283}, keywords = {LTER-MCM}, author = {Robert A. Wharton Jr. and J. Crosby and Christopher P. McKay and J. Rice} } @article {1597, title = {The Photosynthetic Apparatus of Phytoplankton from a Perennially Ice-Covered Antarctic Lake: Acclimation to an Extreme Shade Environment}, journal = {Plant Cell Physiology}, volume = {36}, year = {1995}, pages = {253-263}, keywords = {LTER-MCM}, author = {Patrick J. Neale and John C. Priscu} } @article {1598, title = {Phototactic response of phytoplankton forming discrete layers within the water column of Lake Bonney , Antarctica}, journal = {Antarctic Journal of the US}, volume = {30}, year = {1995}, pages = {301-303}, keywords = {LTER-MCM}, author = {John C. Priscu and Patrick J. Neale} } @article {1599, title = {Phytoplankton Nutrient Deficiency in Lakes of the McMurdo Dry Valleys, Antarctica}, journal = {Freshwater Biology}, volume = {34}, year = {1995}, pages = {215-227}, keywords = {LTER-MCM, legacy}, author = {John C. Priscu} } @article {1600, title = {Profiles of electrode potential and dissolved oxygen in lakes of the McMurdo Dry Valleys}, journal = {Antarctic Journal of the U.S.}, volume = {30}, year = {1995}, pages = {305-307}, keywords = {LTER-MCM}, author = {Malcolm T. Downes and John C. Priscu} } @article {1626, title = {Paleolimnology of the McMurdo Dry Valleys, Antarctica}, journal = {Journal of Paleolimnology}, volume = {10}, year = {1994}, pages = {85-114}, keywords = {LTER-MCM}, doi = {10.1007/BF00682507}, author = {Peter T. Doran and Robert A. Wharton Jr. and W. Berry Lyons} } @article {1627, title = {Phytoplankton population dynamics in perennially ice-covered Lake Fryxell, Antarctica}, journal = {Journal of Plankton Research}, volume = {16}, year = {1994}, pages = {527-541}, keywords = {LTER-MCM}, author = {Sarah A. Spaulding and Diane M. McKnight and Richard L. Smith and Richard Dufford} } @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 {1643, title = {Phytoplankton utilization of ammonium and nitrate in Lake Bonney: A preliminary assessment.}, journal = {Antarctic Journal of the U.S.}, volume = {28}, year = {1993}, pages = {241-243}, keywords = {LTER-MCM}, author = {Christopher D. Woolston and John C. Priscu} } @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} } @article {1651, title = {Photosynthesis-Irradiance Relationships in Phytoplankton From the Physically Stable Water Column of a Perennially Ice-Covered Lake (Lake Bonney, Antarctica)}, journal = {J. Phycol.}, volume = {28}, year = {1992}, pages = {179-185}, keywords = {LTER-MCM}, author = {Michael P. Lizotte and John C. Priscu} } @article {1659, title = {Photon Dependence of Inorganic Nitrogen Transport by Phytoplankton in Perennially Ice-Covered Antarctic Lakes}, journal = {Hydrobiologia}, volume = {172}, year = {1989}, pages = {173-182}, keywords = {LTER-MCM}, author = {John C. Priscu} } @article {1661, title = {Photosynthate Distribution by Microplankton in Permanently Ice-Covered Antarctic Desert Lakes}, journal = {Limnol. Oceanogr.}, volume = {32}, year = {1987}, pages = {260-270}, keywords = {LTER-MCM}, author = {John C. Priscu and Linda R. Priscu and Warwick F. Vincent and Clive Howard-Williams} }