02348nas a2200217 4500008004100000022001400041245012100055210006900176260001200245520149200257653001101749653001801760653002201778653001501800653001301815653001701828100002101845700002301866700002201889856021901911 2025 eng d a0954-102000aMicrobial mat activity and soil biogeochemistry across variable phosphorus availability in Taylor Valley, Antarctica0 aMicrobial mat activity and soil biogeochemistry across variable  c05/20253 a

Primary production is fundamental to ecosystems, and in many extreme environments production is facilitated by microbial mats. Microbial mats are complex assemblages of photo- and heterotrophic microorganisms colonizing sediment and soil surfaces. These communities are the dominant producers of the McMurdo Dry Valleys, Antarctica, where they occupy lentic and lotic environments as well as intermittently wet soils. While the influence of microbial mats on stream nutrient dynamics and lake organic matter cycling is well documented, the influence of microbial mats on underlying soil is less well understood, particularly the effects of microbial mat nitrogen and carbon fixation. Taylor Valley soils occur across variable levels of inorganic phosphorus availability, with the Ross Sea drift containing four times that of the Taylor drifts, providing opportunities to examine how soil geochemistry influences microbial mats and the ecological functions they regulate. We found that inorganic phosphorus availability is positively correlated with microbial mat biomass, pigment concentration and nitrogen fixation potential. Additionally, our results demonstrate that dense microbial mats influence the ecological functioning of underlying soils by enriching organic carbon and total nitrogen stocks (two times higher). This work contributes to ongoing questions regarding the sources of energy fuelling soil food webs and the regional carbon balance in the McMurdo Dry Valleys.

10acarbon10acyanobacteria10anitrogen fixation10aphosphorus10apigments10asoil ecology1 aPower, Sarah, N.1 aOsburn, Ernest, D.1 aBarrett, John, E. uhttps://www.cambridge.org/core/journals/antarctic-science/article/microbial-mat-activity-and-soil-biogeochemistry-across-variable-phosphorus-availability-in-taylor-valley-antarctica/0655E2F09B8D6961618B8F396BA692F202426nas a2200241 4500008004100000022001400041245010000055210006900155260001200224490000800236520166500244653001501909653001701924653002901941653002401970653002201994653001902016100002202035700002202057700001502079700002102094856006902115 2025 eng d a2169-895300aMorphology and distribution of bubble-supported microbial mats from ice-covered Antarctic lakes0 aMorphology and distribution of bubblesupported microbial mats fr c03/20250 v1303 a

Gas bubbles directly influence the macromorphology of benthic microbial mats resulting in preservable biosedimentary structures. This study characterizes the morphology and distribution of microbial mats growing in gas-supersaturated, perennially ice-covered lakes Fryxell, Joyce, and Hoare of the McMurdo Dry Valleys of Antarctica. Photosynthetic benthic mats within the gas-supersaturated zone trap oxygen-rich bubbles and become buoyant, tearing off the bottom as “liftoff mats.” These liftoff mats form a succession of morphologies starting with bubble-induced deformation of flat mats into tent, ridge, and finger liftoff mat. With progressive deformation, mats tear, forming sheet liftoff, while multiple cycles of deformation and tearing transform sheet into strip liftoff. Some mats detach from the substrate and float to the underside of the ice. The depth range of the liftoff zone has varied over time at each lake. Downslope expansion of bubble formation brings previously bubble-free, deep-water pinnacle mats into the liftoff zone. When the liftoff zone shallows, liftoff mats at the deeper end deflate and can become scaffolding for additional mat growth. The superposition and relative orientation of liftoff and pinnacle mats can be used to track the maximum depth of the liftoff zone and changes in gas saturation state in these lakes through time. Our results demonstrate that gas bubbles, even when they are transitory, can exert a significant impact on the morphology of microbial mats at larger scales. This provides a way to identify similar structures and gas supersaturated environments in the biosedimentary record.

10aAntarctica10abiosediments10abubble-driven morphology10agas-supersaturation10aice-covered lakes10amicrobial mats1 aJuarez-Rivera, M.1 aMackey, Tyler, J.1 aHawes, Ian1 aSumner, Dawn, Y. uhttps://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024JG00851602587nas a2200313 4500008004100000022001400041245012700055210006900182260001200251300001100263520145800274653001701732653001401749653000801763653001901771653001501790100002301805700001801828700001501846700002401861700002501885700003301910700002901943700001701972700002201989700002102011700002102032856022002053 2024 eng d a0954-102000aMcMurdo Dry Valley lake edge ‘moats’: The ecological intersection between terrestrial and aquatic polar desert habitat0 aMcMurdo Dry Valley lake edge moats The ecological intersection b c04/2024 a1 - 173 a

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

10aconnectivity10aecosystem10aice10amicrobial mats10atransition1 aStone, Michael, S.1 aDevlin, Shawn1 aHawes, Ian1 aWelch, Kathleen, A.1 aGooseff, Michael, N.1 aTakacs-Vesbach, Cristina, D.1 aMorgan-Kiss, Rachael, M.1 aAdams, Byron1 aBarrett, John, E.1 aPriscu, John, C.1 aDoran, Peter, T. uhttps://www.cambridge.org/core/journals/antarctic-science/article/mcmurdo-dry-valley-lake-edge-moats-the-ecological-intersection-between-terrestrial-and-aquatic-polar-desert-habitats/31D94DD51E651603482A3AE6E8A52A5701966nas a2200253 4500008004100000022001400041245010100055210006900156260001200225490000700237520119400244653001701438653001301455653002401468653000901492653000901501653002101510100002301531700002401554700002201578700002001600700002101620856007101641 2024 eng d a1523-043000aMeasuring and modelling functional moat area in perennially ice-covered Lake Fryxell, Antarctica0 aMeasuring and modelling functional moat area in perennially icec c10/20240 v563 a

The perennially ice-covered lakes of the McMurdo Dry Valleys (MDVs), Antarctica, are an important reservoir of liquid water in an arid and largely frozen environment. During the austral summer, the margins of these ice covers melt, forming a “moat” of liquid water and thin ice, allowing exchange between lake waters and the atmosphere to occur and serving as an interface between lake, soil, and stream ecosystems. The size of these moats varies from year to year. Here, we have established the first published record of moat area changes at MDVs’ Lake Fryxell through time using manual traces of the moat as observed via satellite imagery. We have also tested a semi-automated approach for measuring moat area and found that it consistently underestimated the manual record, which we suspect may be due to the lower spatial resolution of images used in this versus the manual approach. Finally, we developed a predictive model based on readily available climate data, allowing moat area to be predicted beyond the limits of the satellite-based records. We found that functional moat area varies annually, potentially influencing ecosystem processes in the moats.

10aLake Fryxell10alake ice10aMcMurdo Dry Valleys10amoat10aNDWI10apredictive model1 aStone, Michael, S.1 aSalvatore, Mark, R.1 aDugan, Hilary, A.1 aMyers, Madeline1 aDoran, Peter, T. uhttps://www.tandfonline.com/doi/full/10.1080/15230430.2024.240662602619nas a2200205 4500008004100000245006000041210006000101260006000161300000800221490001000229520198900239653001302228653002702241653001302268653001702281653001002298100002402308700003302332856004802365 2024 eng d00aMetagenomic analysis of Antarctic microbial communities0 aMetagenomic analysis of Antarctic microbial communities aAlbuquerque, NM, USAbUniversity of New Mexicoc06/2024 a1360 vPh.D.3 a

The research presented in this dissertation focuses on microbial roles in biogeochemical cycling in Antarctic aquatic environments. The major objective of my research was to examine the impact of biotic and abiotic pressures on nutrient cycling in microbially dominated systems. I used three perennially ice covered lakes in the McMurdo Dry Valleys (MDVs) along with subglacial lakes Whillans and Mercer as natural case studies. The MDVs are located in Victoria Land, East Antarctica and have been studied since 1993 as part of the McMurdo Long Term Ecological Research Project. Viruses in the MDVs were shown to be seasonally abundant and have high infection rates. My work built upon this previous research by showing that viruses are also diverse and potentially re-direct host metabolism through auxiliary metabolic genes (AMGs). Subglacial lake Whillans and Mercer lie underneath 800 and 1100 meters of ice respectively beneath the West Antarctic Ice Sheet. Previous studies in subglacial lakes Whillans have shown an active prokaryotic community. Through viral-like particle counts, microscopy, and metagenomics, we established the presence and potential metabolic influence of viruses in both Whillans and Mercer. In MDV lakes have an extensive high-throughput DNA dataset studying microbial communities through the 16S rRNA gene. We used metagenomic sequencing within two MCM lakes at multiple depths to build upon these previous datasets by annotating metagenomically assembled genomes for functional characteristics. This project highlights the lakes' vertical redox gradient, showing that dominant taxa, nutrient cycling genes, and metabolic potentials change down the water column. The MDVs serve as a biological indicator for climate change in continental Antarctica and functional changes serve as important indicators of climate change. Taken together, this dissertation shows the importance of multi-kingdom microbial function under oligotrophic conditions.

10abacteria10abiogeochemical cycling10afunction10ametagenomics10avirus1 aRobinson, David, M.1 aTakacs-Vesbach, Cristina, D. uhttps://www.proquest.com/docview/311991058501851nas a2200229 4500008004100000022001400041245013100055210006900186260001200255300001400267490000600281520108300287100002201370700001801392700002501410700002201435700001801457700002701475700002101502700002501523856007301548 2023 eng d a2378-224200aMacroSheds: A synthesis of long-term biogeochemical, hydroclimatic, and geospatial data from small watershed ecosystem studies0 aMacroSheds A synthesis of longterm biogeochemical hydroclimatic  c06/2023 a419 - 4520 v83 a

The US Federal Government supports hundreds of watershed monitoring efforts from which solute fluxes can be calculated. Although instrumentation and methods vary between studies, the data collected and their motivating questions are remarkably similar. Nevertheless, little effort toward their compilation has previously been made. The MacroSheds project has developed a future-friendly system for harmonizing daily time series of streamflow, precipitation, and solute chemistry from 169+ watersheds, and supplementing each with watershed attributes. Here, we describe the breadth of MacroSheds data, and detail the steps involved in rendering each data product. We provide recommendations for usage and discuss when other datasets might be more suitable. The MacroSheds dataset is an unprecedented resource for watershed science, and for hydrology, as a small-watershed supplement to existing collections of streamflow predictors, like CAMELS and GAGES-II. The MacroSheds platform includes a web dashboard for visualization and an R package for data access and analysis.

1 aVlah, Michael, J.1 aRhea, Spencer1 aBernhardt, Emily, S.1 aSlaughter, Weston1 aGubbins, Nick1 aDelVecchia, Amanda, G.1 aThellman, Audrey1 aRoss, Matthew, R. V. uhttps://aslopubs.onlinelibrary.wiley.com/doi/full/10.1002/lol2.1032502348nas a2200253 4500008004100000022001400041245009900055210006900154260001200223300001100235520137700246653002501623653001901648653002401667653003201691653001701723100002601740700002401766700002501790700002501815700003201840700002001872856020201892 2023 eng d a0022-143000aMeteorological drivers of melt at two nearby glaciers in the McMurdo Dry Valleys of Antarctica0 aMeteorological drivers of melt at two nearby glaciers in the McM c12/2023 a1 - 133 a

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

10aAntarctic glaciology10aenergy balance10aglacier meteorology10aice/atmosphere interactions10amelt-surface1 aHofsteenge, Marte, G.1 aCullen, Nicolas, J.1 aConway, Jonathan, P.1 aReijmer, Carleen, H.1 avan den Broeke, Michiel, R.1 aKaturji, Marwan uhttps://www.cambridge.org/core/journals/journal-of-glaciology/article/meteorological-drivers-of-melt-at-two-nearby-glaciers-in-the-mcmurdo-dry-valleys-of-antarctica/2B8ED17DEC26AB5F0905BC4C7ACA02FA02238nas a2200205 4500008004100000245004700041210004700088260004800135490001000183520164300193653001501836653002901851653002201880653001901902653001001921653001001931100002601941700001701967856004801984 2023 eng d00aMicrobial life in challenging environments0 aMicrobial life in challenging environments aBoulder, CObUniversity of Colorado Boulder0 vPh.D.3 a

Microorganisms are nearly ubiquitous on Earth, but the identity and function of microbial communities are inherently dependent on the properties of the specific environment in question. Here, I have studied soils around the world to answer questions about how the functional attributes of microorganisms allow them to respond to challenging environmental conditions. First, I explore how microbial communities in soils change across environmental gradients in Antarctica. I show that microbes in Antarctic surface soils are most restricted by low temperatures, low water availability, and high concentrations of salt. Microbial communities near the polar plateau, the most challenging environment, are dominated by Actinobacteria and Chloroflexi, and are enriched in genes associated with the oxidation of hydrogen gas as an energy source. Second, I show that the earliest microbial colonizers of a newly-formed volcanic island in the Kingdom of Tonga are chemolithotrophs that appear to have come from nearby geothermal systems. While many of these microbes utilize sulfur as an energy source, the most abundant organisms have genes that indicate they can oxidize trace gases including carbon monoxide and hydrogen. Finally, I show that organisms associated with carbon limited subsurface soils tend to have smaller genomes, grow more slowly, and have more gene pathways associated with metabolism and the storage of carbon. Taken together, these studies shed light on microbial survival in challenging soil environments and show the varied ways in which microbial communities interact with and are affected by their surroundings.

10aAntarctica10aenvironmental conditions10amicrobial ecology10amicroorganisms10asoils10atonga1 aDragone, Nicholas, B.1 aFierer, Noah uhttps://www.proquest.com/docview/281473420902981nas a2200253 4500008004100000022001400041245011200055210006900167260001200236300001400248490000700262520216600269653002102435653002602456653002602482100002802508700002202536700002202558700002102580700002202601700001802623700001502641856007102656 2021 eng d a1523-043000aThe magnitude and climate sensitivity of isotopic fractionation from ablation of Antarctic Dry Valley lakes0 amagnitude and climate sensitivity of isotopic fractionation from c12/2021 a352 - 3710 v533 a

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

10aDry Valley lakes10aisotope fractionation10astable water isotopes1 aBellagamba, Anthony, W.1 aBerkelhammer, Max1 aWinslow, Luke, A.1 aDoran, Peter, T.1 aMyers, Krista, F.1 aDevlin, Shawn1 aHawes, Ian uhttps://www.tandfonline.com/doi/full/10.1080/15230430.2021.200189901707nam a2200205 4500008004100000020001800041245013400059210006900193260001300262520102300275653001501298653001701313653001201330653001201342653001801354653000901372100002401381700002101405856007501426 2021 eng d a978012820245600aThe McMurdo Dry Valleys of Antarctica: A geological, environmental, and ecological analog to the Martian surface and near surface0 aMcMurdo Dry Valleys of Antarctica A geological environmental and bElsevier3 a

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

10aAntarctica10aastrobiology10aclimate10ageology10ageomorphology10aMars1 aSalvatore, Mark, R.1 aLevy, Joseph, S. uhttps://www.sciencedirect.com/science/article/pii/B978012820245600011202329nas a2200193 4500008004100000022001400041245010500055210006900160260001200229300001200241490000700253520164000260100002301900700002601923700001901949700002201968700002601990856011902016 2021 eng d a1527-140400aMeta-analysis of Cryogenian through modern quartz microtextures reveals sediment transport histories0 aMetaanalysis of Cryogenian through modern quartz microtextures r c09/2021 a929-9440 v913 a

Quantitative analysis of quartz microtextures by means of scanning electron microscopy (SEM) can reveal the transport histories of modern and ancient sediments. However, because workers identify and count microtextures differently, it is difficult to directly compare quantitative microtextural data analyzed by different workers. As a result, the defining microtextures of certain transport modes and their probabilities of occurrence are not well constrained. We used principal-component analysis (PCA) to directly compare modern and ancient aeolian, fluvial, and glacial samples from the literature with nine new samples from active aeolian and glacial environments. Our results demonstrate that PCA can group microtextural samples by transport mode and differentiate between aeolian transport and fluvial and glacial transport across studies. The PCA ordination indicates that aeolian samples are distinct from fluvial and glacial samples, which are in turn difficult to disambiguate from each other. Ancient and modern sediments are also shown to have quantitatively similar microtextural relationships. Therefore, PCA may be a useful tool to constrain the ambiguous transport histories of some ancient sediment grains. As a case study, we analyzed two samples with ambiguous transport histories from the Cryogenian Bråvika Member (Svalbard). Integrating PCA with field observations, we find evidence that the Bråvika Member facies investigated here includes aeolian deposition and may be analogous to syn-glacial Marinoan aeolian units including the Bakoye Formation in Mali and the Whyalla Sandstone in South Australia.

1 aReahl, Jocelyn, N.1 aCantine, Marjorie, D.1 aWilcots, Julia1 aMackey, Tyler, J.1 aBergmann, Kristin, D. uhttps://pubs.geoscienceworld.org/jsedres/article/91/9/929/607764/Meta-analysis-of-Cryogenian-through-modern-quartz02224nas a2200229 4500008004100000245016400041210006900205260001200274300000800286490000700294520144700301100002401748700002301772700002201795700001501817700002101832700002201853700002201875700003201897700002101929856004401950 2021 eng d00aMetabolic capacity of the Antarctic cyanobacterium Phormidium pseudopriestleyi that sustains oxygenic photosynthesis in the presence of hydrogen sulfide0 aMetabolic capacity of the Antarctic cyanobacterium IPhormidium p c03/2021 a4260 v123 a

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

1 aLumian, Jessica, E.1 aJungblut, Anne, D.1 aDillon, Megan, L.1 aHawes, Ian1 aDoran, Peter, T.1 aMackey, Tyler, J.1 aDick, Gregory, J.1 aGrettenberger, Christen, L.1 aSumner, Dawn, Y. uhttps://www.mdpi.com/2073-4425/12/3/42602448nas a2200217 4500008004100000245010000041210006900141260001200210490000700222520174400229100001201973700001901985700002702004700002102031700001602052700001702068700002902085700002302114700002102137856007202158 2020 eng d00aMethane production in the oxygenated water column of a perennially ice‐covered Antarctic lake0 aMethane production in the oxygenated water column of a perennial c01/20200 v653 a

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

1 aLi, Wei1 aDore, John, E.1 aSteigmeyer, August, J.1 aCho, Yong‐Joon1 aKim, Ok-Sun1 aLiu, Yongqin1 aMorgan-Kiss, Rachael, M.1 aSkidmore, Mark, L.1 aPriscu, John, C. uhttps://aslopubs.onlinelibrary.wiley.com/doi/full/10.1002/lno.1125702112nas a2200229 4500008004100000245006600041210006600107260001200173490000700185520130800192653001901500653001901519653002001538653002301558653001301581100002801594700002201622700002201644700002401666700002301690856016901713 2020 eng d00aModeling present and future ice covers in two Antarctic lakes0 aModeling present and future ice covers in two Antarctic lakes c02/20200 v663 a

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

10aclimate change10aenergy balance10aice and climate10aice-sheet modeling10alake ice1 aEcheverría, Sebastián1 aHausner, Mark, B.1 aBambach, Nicolás1 aVicuña, Sebastián1 aSuárez, Francisco uhttps://www.cambridge.org/core/journals/journal-of-glaciology/article/modeling-present-and-future-ice-covers-in-two-antarctic-lakes/9306439ADD5492BC05F3BAF0E076B1C302454nas a2200289 4500008004100000022001400041245011100055210006900166260001200235300001600247490000700263520153600270653001501806653001501821653003701836653002101873653002401894653003201918100002001950700001601970700002601986700002102012700001402033700002302047700001502070856007902085 2019 eng d a1558-842400aMeteorological connectivity from regions of high biodiversity within the McMurdo Dry Valleys of Antarctica0 aMeteorological connectivity from regions of high biodiversity wi c11/2019 a2437 - 24520 v583 a

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

10aAntarctica10aatmosphere10abiosphere-atmosphere interaction10amesoscale models10amesoscale processes10anumerical analysis/modeling1 aKaturji, Marwan1 aKhan, Basit1 aSprenger, Michael, A.1 aDatta, Rajasweta1 aJoy, Kurt1 aZawar-Reza, Peyman1 aHawes, Ian uhttps://journals.ametsoc.org/view/journals/apme/58/11/jamc-d-18-0336.1.xml01901nas a2200169 4500008004100000245010500041210006900146260004900215490000900264520132500273653001301598653001201611653001301623100002401636700002601660856004501686 2018 eng d00aMicrobial and CO2 responses to water stresses show decreased productivity and diversity through time0 aMicrobial and CO2 responses to water stresses show decreased pro aProvo, UTbBrigham Young Universityc05/20180 vM.S.3 a

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.

10adormancy10aPiCRUST10aturnover1 aRobinson, David, M.1 aAanderud, Zachary, T. uhttps://scholarsarchive.byu.edu/etd/683002036nas a2200145 4500008004100000245014100041210006900182260001200251490000700263520148900270100002301759700002901782700001701811856006201828 2017 eng d00aMultiple ice-binding proteins of probable prokaryotic origin in an Antarctic lake alga, Chlamydomonas sp. ICE-MDV (Chlorophyceae)0 aMultiple icebinding proteins of probable prokaryotic origin in a c08/20170 v533 a

Ice‐associated algae produce ice‐binding proteins (IBPs) to prevent freezing damage. The IBPs of the three chlorophytes that have been examined so far share little similarity across species, making it likely that they were acquired by horizontal gene transfer (HGT). To clarify the importance and source of IBPs in chlorophytes, we sequenced the IBP genes of another Antarctic chlorophyte, Chlamydomonas sp. ICE‐MDV (Chlamy‐ICE). Genomic DNA and total RNA were sequenced and screened for known ice‐associated genes. Chlamy‐ICE has as many as 50 IBP isoforms, indicating that they have an important role in survival. The IBPs are of the DUF3494 type and have similar exon structures. The DUF3494 sequences are much more closely related to prokaryotic sequences than they are to sequences in other chlorophytes, and the chlorophyte IBP and ribosomal 18S phylogenies are dissimilar. The multiple IBP isoforms found in Chlamy‐ICE and other algae may allow the algae to adapt to a greater variety of ice conditions than prokaryotes, which typically have a single IBP gene. The predicted structure of the DUF3494 domain has an ice‐binding face with an orderly array of hydrophilic side chains. The results indicate that Chlamy‐ICE acquired its IBP genes by HGT in a single event. The acquisitions of IBP genes by this and other species of Antarctic algae by HGT appear to be key evolutionary events that allowed algae to extend their ranges into polar environments.

1 aRaymond, James, A.1 aMorgan-Kiss, Rachael, M.1 aValentin, K. uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/jpy.1255000845nas a2200193 4500008004100000022001400041245014300055210006900198260001600267300001400283490000700297100002100304700002800325700002900353700003300382700002200415700002100437856019300458 2016 eng d a0006-356800aMicrobial Community Dynamics in Two Polar Extremes: The Lakes of the McMurdo Dry Valleys and the West Antarctic Peninsula Marine Ecosystem0 aMicrobial Community Dynamics in Two Polar Extremes The Lakes of  cJan-10-2016 a829 - 8470 v661 aBowman, Jeff, S.1 aVick-Majors, Trista, J.1 aMorgan-Kiss, Rachael, M.1 aTakacs-Vesbach, Cristina, D.1 aDucklow, Hugh, W.1 aPriscu, John, C. uhttps://academic.oup.com/bioscience/article-lookup/doi/10.1093/biosci/biw103https://academic.oup.com/bioscience/article/66/10/829/2236137/Microbial-Community-Dynamics-in-Two-Polar-Extremes00676nas a2200181 4500008004100000245012900041210006900170260001200239490000600251100002400257700002000281700002400301700002200325700002500347700002100372700003300393856006800426 2016 eng d00aMicrobial Community Responses to Increased Water and Organic Matter in the Arid Soils of the McMurdo Dry Valleys, Antarctica0 aMicrobial Community Responses to Increased Water and Organic Mat c07/20160 v71 aBuelow, Heather, N.1 aWinter, Ara, S.1 aVan Horn, David, J.1 aBarrett, John, E.1 aGooseff, Michael, N.1 aSchwartz, Egbert1 aTakacs-Vesbach, Cristina, D. uhttp://journal.frontiersin.org/article/10.3389/fmicb.2016.0104000604nas a2200169 4500008004100000245007900041210006900120260001600189490000600205100002200211700002500233700002700258700002100285700002300306700002800329856007700357 2016 eng d00aMicrobial Community Structure of Subglacial Lake Whillans, West Antarctica0 aMicrobial Community Structure of Subglacial Lake Whillans West A cOct-09-20170 v71 aAchberger, Amanda1 aChristner, Brent, C.1 aMichaud, Alexander, B.1 aPriscu, John, C.1 aSkidmore, Mark, L.1 aVick-Majors, Trista, J. uhttp://journal.frontiersin.org/Article/10.3389/fmicb.2016.01457/abstract00761nas a2200241 4500008004100000022001400041245009900055210006900154260001200223300001400235490000700249100002300256700001500279700002200294700001800316700002100334700002100355700002400376700001900400700002700419700001800446856005500464 2016 eng d a0099-224000aMicrobial Mat Communities along an Oxygen Gradient in a Perennially Ice-Covered Antarctic Lake0 aMicrobial Mat Communities along an Oxygen Gradient in a Perennia c01/2016 a620 - 6300 v821 aJungblut, Anne, D.1 aHawes, Ian1 aMackey, Tyler, J.1 aKrusor, Megan1 aDoran, Peter, T.1 aSumner, Dawn, Y.1 aEisen, Jonathan, A.1 aHillman, Colin1 aGoroncy, Alexander, K.1 aStams, A., J. uhttp://aem.asm.org/lookup/doi/10.1128/AEM.02699-1502725nas a2200133 4500008004100000245007400041210006900115260004200184490001000226520224900236100002702485700002102512856005802533 2016 eng d00aMicrobially mediated biogeochemical cycles in polar ice covered lakes0 aMicrobially mediated biogeochemical cycles in polar ice covered  aBozeman, MTbMontana State University0 vPh.D.3 a

Lakes are important sites for globally-relevant biogeochemical cycles mediated by microorganisms. In the Arctic, seasonally ice covered thermokarst lakes are a large component in Earth's carbon cycle due to their methane emissions from organic carbon degradation. In the Antarctic, over 400 unexplored lakes exist beneath the Antarctic ice sheet with unknown biogeochemical contributions to the Earth system. This dissertation seeks to investigate the biogeochemical role of microorganisms in the lake habitat and how they interact with the seasonal and permanent ice covers of lakes in polar environments. Microbiologically clean hot water drilling was used to access a subglacial lake beneath Antarctica's ice to collect, for the first time, intact sediment and water samples. Laboratory experiments on Arctic and Antarctic, seasonally and perennially, respectively, ice covered lakes were used to investigate the impact of lake ice freezing regimes on microorganisms. My results show that subglacial lake sediments beneath the West Antarctic Ice Sheet contain solute ratios that suggest relict marine sediments were deposited during previous interglacial periods. Microbial activity overprints the marine geochemical signature to produce fluxes of ions into the Subglacial Lake Whillans water column, which ultimately drains to the Southern Ocean. Microbial activity in Subglacial Lake Whillans is partially fueled by biologically-formed methane diffusing from below our deepest collected (~38 cm) subglacial sediment samples. The ice above Subglacial Lake Whillans appears to be an important source of molecular oxygen for microorganisms to drive oxidative physiologies. My experimental evidence shows microorganisms incorporate into lake ice cover to, potentially, avoid increasing stressors from progressive lake ice freezing. Taken together, the results from this dissertation reinforce the hypothesis that subglacial environments beneath the Antarctic ice sheet are habitats for life. Further, the microorganisms in subglacial lakes participate in globally-relevant biogeochemical cycles. Here, I extend the extent of the biosphere and show sediments at the base of ice sheets are an active component of the Earth system.

1 aMichaud, Alexander, B.1 aPriscu, John, C. uhttps://scholarworks.montana.edu/xmlui/handle/1/1379302072nas a2200193 4500008004100000245010300041210006900144260005100213490000900264520138000273653003401653653004201687653002201729653002401751653001201775100002401787700002201811856004501833 2016 eng d00aModeling Surface Photosynthetic Active Radiation in Taylor Valley, McMurdo Dry Valleys, Antarctica0 aModeling Surface Photosynthetic Active Radiation in Taylor Valle aChicago, ILbUniversity of Illinois at Chicago0 vM.S.3 a

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.

 

10adigital elevation model (DEM)10ageographical information system (GIS)10aice-covered lakes10ameteorological data10aR model1 aAcosta, Dimitri, R.1 aBerkelhammer, Max uhttp://indigo.uic.edu/handle/10027/2118002208nas a2200181 4500008004100000022001400041245010400055210006900159260001200228300001100240520160100251100002201852700002101874700001801895700002701913700002101940856006501961 2016 eng d a0022-143000aModeling the thickness of perennial ice covers on stratified lakes of the Taylor Valley, Antarctica0 aModeling the thickness of perennial ice covers on stratified lak c06/2016 a1 - 103 a
A 1-D ice cover model was developed to predict and constrain drivers of long-term ice thickness trends in chemically stratified lakes of Taylor Valley, Antarctica. The model is driven by surface radiative heat fluxes and heat fluxes from the underlying water column. The model successfully reproduced 16 a (between 1996 and 2012) of ice thickness changes for the west lobe of Lake Bonney (average ice thickness = 3.53 m) and Lake Fryxell (average ice thickness = 4.22 m). Long-term ice thickness trends require coupling with the thermal structure of the water column. The heat stored within the temperature maximum of lakes exceeding a liquid water column depth of 20 m can either impede or facilitate ice thickness change depending on the predominant climatic trend (cooling or warming). As such, shallow (<20 m deep water columns) perennially ice-covered lakes without deep temperature maxima are more sensitive indicators of climate change. The long-term ice thickness trends are a result of surface energy flux and heat flux from the deep temperature maximum in the water column, the latter of which results from absorbed solar radiation.

 

1 aObryk, Maciek, K.1 aDoran, Peter, T.1 aHicks, J., A.1 aMcKay, Christopher, P.1 aPriscu, John, C. uhttp://www.journals.cambridge.org/abstract_S002214301600069100801nas a2200253 4500008004100000022001400041245008400055210006900139260001200208300000800220490000700228100003400235700002400269700002200293700002600315700002500341700002400366700001700390700002200407700002300429700002600452700002200478856004700500 2015 eng d a1445-522600aMitochondrial DNA analyses reveal widespread tardigrade diversity in Antarctica0 aMitochondrial DNA analyses reveal widespread tardigrade diversit c12/2015 a5780 v291 aVelasco-Castrillon, Alejandro1 aMcInnes, Sandra, J.1 aSchultz, Mark, B.1 aArroniz-Crespo, Maria1 aD'Haese, Cyrille, A.1 aGibson, John, A. E.1 aAdams, Byron1 aPage, Timothy, J.1 aAustin, Andrew, D.1 aCooper, Steven, J. B.1 aStevens, Mark, I. uhttp://www.publish.csiro.au/?paper=IS1401902542nas a2200181 4500008004100000022001300041245006800054210006300122260001200185300001200197490000800209520181900217100002402036700002102060700002502081700002402106856023002130 2014 eng d a0169555X00aThe McMurdo Dry Valleys: A landscape on the threshold of change0 aMcMurdo Dry Valleys A landscape on the threshold of change c11/2014 a25 - 350 v2253 a

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

1 aFountain, Andrew, G1 aLevy, Joseph, S.1 aGooseff, Michael, N.1 aVan Horn, David, J. uhttp://linkinghub.elsevier.com/retrieve/pii/S0169555X14001780http://api.elsevier.com/content/article/PII:S0169555X14001780?httpAccept=text/xmlhttp://api.elsevier.com/content/article/PII:S0169555X14001780?httpAccept=text/plain00428nas a2200109 4500008004100000245009200041210006900133260001200202100001600214700002300230856006500253 2014 eng d00aMicrobial biomass and respiration responses to nitrogen fertilization in a polar desert0 aMicrobial biomass and respiration responses to nitrogen fertiliz c01/20141 aBall, Becky1 aVirginia, Ross, A. uhttp://link.springer.com/article/10.1007%2Fs00300-014-1459-000531nas a2200121 4500008004100000245013000041210006900171260001200240100002800252700002100280700003000301856007800331 2014 eng d00aModular community structure suggests metabolic plasticity during the transition to polar night in ice-covered Antarctic lakes0 aModular community structure suggests metabolic plasticity during c10/20131 aVick-Majors, Trista, J.1 aPriscu, John, C.1 aAmaral-Zettler, Linda, A. uhttp://www.nature.com/ismej/journal/vaop/ncurrent/full/ismej2013190a.html02033nas a2200229 4500008004100000245011500041210006900156260001200225300001100237490000600248520129700254100002701551700001901578700002101597700002901618700002001647700002001667700002301687700001801710700002401728856005101752 2013 eng d00aMicrobial growth under humic-free conditions in a supraglacial stream system on the Cotton Glacier, Antarctica0 aMicrobial growth under humicfree conditions in a supraglacial st c09/2013 a0350220 v83 aDuring the austral summers of 2004 and 2009, we sampled a supraglacial stream on the Cotton Glacier, Antarctica. The stream dissolved organic matter (DOM) was low (44–48 μM C) and lacked detectable humic fluorescence signatures. Analysis of the excitation emissions matrices (EEMs) indicated that amino-acid fluorophores dominated, consistent with DOM of microbial origin, with little humic-like fluorescence. In most aquatic ecosystems, humic DOM attenuates harmful UV radiation and its absence may represent an additional stressor influencing the microbial community. Nonetheless, the stream contained an active microbial assemblage with bacterial cell abundances from 2.94 × 104 to 4.97 × 105 cells ml−1, and bacterial production ranging from 58.8 to 293.2 ng C l−1 d−1. Chlorophyll-a concentrations ranged from 0.3 to 0.53 μg l−1 indicating that algal phototrophs were the probable source of the DOM. Microbial isolates produced a rainbow of pigment colors, suggesting adaptation to stress, and were similar to those from other cryogenic systems (Proteobacteria and Bacteroidetes lineages). Supraglacial streams provide an example of contemporary microbial processes on the glacier surface and a natural laboratory for studying microbial adaptation to the absence of humics.1 aForeman, Christine, M.1 aCory, Rose, M.1 aMorris, Cindy, E1 aSanClements, Michael, D.1 aSmith, Heidi, J1 aLisle, John, T.1 aMiller, Penney, L.1 aChin, Yu-Ping1 aMcKnight, Diane, M. uhttp://iopscience.iop.org/1748-9326/8/3/03502200572nas a2200145 4500008004100000245015400041210006900195260001200264300001400276490000700290100001900297700002100316700001800337856007100355 2013 eng d00aMicro-hole and multigrain quartz luminescence dating of Paleodeltas at Lake Fryxell, McMurdo Dry Valleys (Antarctica), and relevance for lake history0 aMicrohole and multigrain quartz luminescence dating of Paleodelt c12/2013 a119 - 1340 v181 aBerger, G., W.1 aDoran, Peter, T.1 aThomsen, K.J. uhttp://www.sciencedirect.com/science/article/pii/S187110141300042300548nas a2200133 4500008004100000245010500041210006900146260001200215300001400227490001200241100001600253700002300269856012200292 2012 eng d00aMeltwater seep patches increase heterogeneity of soil geochemistry and therefore habitat suitability0 aMeltwater seep patches increase heterogeneity of soil geochemist c11/2012 a652 - 6600 v189-1901 aBall, Becky1 aVirginia, Ross, A. uhttps://mcm.lternet.edu/content/meltwater-seep-patches-increase-heterogeneity-soil-geochemistry-and-therefore-habitat00684nas a2200193 4500008004100000245011200041210006900153260001200222300001400234490000700248100001800255700002200273700002100295700002100316700002800337700002000365700002800385856007700413 2012 eng d00aMicrobial dynamics and flagellate grazing during transition to winter in Lakes Hoare and Bonney, Antarctica0 aMicrobial dynamics and flagellate grazing during transition to w c11/2012 a449 - 4580 v821 aThurman, Jill1 aParry, Jacqueline1 aHill, Philip, J.1 aPriscu, John, C.1 aVick-Majors, Trista, J.1 aChiuchiolo, Amy1 aLaybourn-Parry, Johanna uhttp://onlinelibrary.wiley.com/doi/10.1111/j.1574-6941.2012.01423.x/full01017nas a2200337 4500008004100000022001400041245007500055210006900130260001200199300001800211490000800229100001900237700001800256700002700274700002700301700002300328700002000351700001900371700002400390700002500414700001700439700001800456700002100474700002700495700002400522700001800546700001900564700001900583700002100602856005600623 2012 eng d a0027-842400aMicrobial life at -13  C in the brine of an ice-sealed Antarctic lake0 aMicrobial life at 13 C in the brine of an icesealed Antarctic la c12/2012 a20626 - 206310 v1091 aMurray, A., E.1 aKenig, Fabien1 aFritsen, Christian, H.1 aMcKay, Christopher, P.1 aCawley, Kaelin, M.1 aEdwards, R., L.1 aKuhn, Emanuele1 aMcKnight, Diane, M.1 aOstrom, Nathaniel, E1 aPeng, Vivian1 aPonce, Adrian1 aPriscu, John, C.1 aSamarkin, Vladimir, A.1 aTownsend, Ashley, T1 aWagh, Protima1 aYoung, Seth, A1 aYung, Pung, To1 aDoran, Peter, T. uhttp://www.pnas.org/cgi/doi/10.1073/pnas.120860710902199nas a2200205 4500008004100000245013600041210006900177260003400246490000900280520151100289653001401800653001901814653001201833653001401845653002501859653001101884100002401895700002501919856004901944 2012 eng d00aModeling nitrate concentrations in an Antarctic glacial meltwater stream under fluctuating hydrologic conditions and nitrate inputs0 aModeling nitrate concentrations in an Antarctic glacial meltwate bPennsylvania State University0 vM.S.3 a

The McMurdo Dry Valleys comprise a unique polar desert ecosystem in Victoria Land, Antarctica. The hydrologic system in the Dry Valleys is often characterized as being simplified compared to temperate watersheds, due to the ability to identify physical boundaries and nutrient sources and sinks. We seek to characterize the evolution of streamflow, solutes, and nutrients along a glacial meltwater stream in the McMurdo Dry Valleys, and to understand the role of different sources and sinks under varying hydrologic conditions. The study presented here includes streamflow routing, solute modeling, and nitrate concentration modeling in Von Guerard stream, a stream with abundant algal coverage in the McMurdo Dry Valleys region of Antarctica. The streamflow model is a solution to the kinematic wave routing problem. Solute modeling addresses advection, dispersion, as well as hyporheic zone inputs, which are controlled by weathering and hyporheic exchange. Lastly, the nitrate model builds on the solute model with the addition of a gross primary production (GPP) component. Results indicate that the hyporheic source of nitrate is controlling due to rapid exchange with the main channel. GPP impacts are small due to light-saturated conditions for a majority of the season, but provide a consistent sink for nitrate. The role of advective and dispersive transport is highly dependent on flow conditions, with advective transport controlling at high flows and dispersive controlling at low flows.

10ahydrology10ahyporheic zone10anitrate10anutrients10aprimary productivity10astream1 aBernzott, Emily, D.1 aGooseff, Michael, N. uhttps://etda.libraries.psu.edu/catalog/1531600324nas a2200121 4500008004100000245003000041210002900071250001400100260001400114490000900128100002000137856004500157 2011 eng d00aMCM IV: Getting Connected0 aMCM IV Getting Connected aFall 2011 bLTER News0 v20131 aHowkins, Adrian uhttp://news.lternet.edu/Article2316.html00668nas a2200205 4500008004100000022001400041245010700055210006900162260001200231300001600243490000700259100001900266700001600285700001800301700002400319700002000343700002400363700002000387856005500407 2011 eng d a0722-406000aMicroclimate impacts of passive warming methods in Antarctica: implications for climate change studies0 aMicroclimate impacts of passive warming methods in Antarctica im c10/2011 a1421 - 14350 v341 aBokhorst, Stef1 aHuiskes, Ad1 aConvey, Peter1 aSinclair, Brent, J.1 aLebouvier, Marc1 aVan de Vijver, Bart1 aWall, Diana, H. uhttp://link.springer.com/10.1007/s00300-011-0997-y00518nas a2200133 4500008004100000020001800041245007000059210006900129260003600198300001200234100002500246700001700271856009600288 2011 eng d a978184593687700aMolecular analysis of desiccation survival in Antarctic nematodes0 aMolecular analysis of desiccation survival in Antarctic nematode aWallingfordbCABI International a205-2321 aAdhikari, Bishwo, N.1 aAdams, Byron uhttps://mcm.lternet.edu/content/molecular-analysis-desiccation-survival-antarctic-nematodes00627nam a2200145 4500008004100000245012700041210006900168260002200237300001400259100002500273700001700298700001800315700002000333856012800353 2011 eng d00aMolecular and physiological basis of nematode survival: Molecular analyses of desiccation survival in Antarctic nematodes.0 aMolecular and physiological basis of nematode survival Molecular aWallingfordbCABI a205 - 2321 aAdhikari, Bishwo, N.1 aAdams, Byron1 aPerry, R., N.1 aWharton, D., A. uhttps://mcm.lternet.edu/content/molecular-and-physiological-basis-nematode-survival-molecular-analyses-desiccation-survival00597nas a2200169 4500008004100000245007600041210006900117260001200186300001800198490000800216100001600224700001800240700002600258700002000284700002100304856010200325 2011 eng d00aMolecular study of worldwide distribution and diversity of soil animals0 aMolecular study of worldwide distribution and diversity of soil  c10/2011 a17720 - 177250 v1081 aWu, Tiehang1 aAyres, Edward1 aBardgett, Richard, D.1 aWall, Diana, H.1 aGarey, James, R. uhttps://mcm.lternet.edu/content/molecular-study-worldwide-distribution-and-diversity-soil-animals00474nas a2200109 4500008004100000245008300041210006900124260002700193100001400220700002400234856010600258 2010 eng d00aMicrobial interactions with dissolved organic matter in saline natural waters0 aMicrobial interactions with dissolved organic matter in saline n bUniversity of Colorado1 aCawley, K1 aMcKnight, Diane, M. uhttps://mcm.lternet.edu/content/microbial-interactions-dissolved-organic-matter-saline-natural-waters00718nas a2200241 4500008004100000245007300041210006900114300001200183490000600195100001500201700001300216700001800229700002000247700001600267700001300283700001200296700001400308700001500322700001500337700001300352700001300365856009800378 2009 eng d00aManaging for ocean biodiversity to sustain marine ecosystem services0 aManaging for ocean biodiversity to sustain marine ecosystem serv a204-2110 v71 aPalumbi, S1 aNorse, E1 aStachowicz, J1 aWall, Diana, H.1 aSandifer, P1 aAllan, J1 aBeck, M1 aFautin, D1 aFogerty, M1 aHalpern, B1 aIncze, L1 aLeong, J uhttps://mcm.lternet.edu/content/managing-ocean-biodiversity-sustain-marine-ecosystem-services00480nas a2200109 4500008004100000245008700041210006900128260003000197100001600227700001700243856011000260 2009 eng d00aThe Minor Alkaline Earth Element and Alkali Metal Behavior in Closed-basin Lakes0 aMinor Alkaline Earth Element and Alkali Metal Behavior in Closed bThe Ohio State University1 aWitherow, R1 aLyons, Berry uhttps://mcm.lternet.edu/content/minor-alkaline-earth-element-and-alkali-metal-behavior-closed-basin-lakes00633nas a2200157 4500008004100000245012400041210006900165300001200234100001000246700001800256700001000274700002600284700002000310700002100330856012400351 2009 eng d00aMolecular profiling of soil animal diversity in natural ecosystems: incongruence of molecular and morphological results0 aMolecular profiling of soil animal diversity in natural ecosyste a849-8571 aWu, T1 aAyres, Edward1 aLi, G1 aBardgett, Richard, D.1 aWall, Diana, H.1 aGarey, James, R. uhttps://mcm.lternet.edu/content/molecular-profiling-soil-animal-diversity-natural-ecosystems-incongruence-molecular-and00397nas a2200121 4500008004100000245005100041210005100092300001400143490000700157100001600164700001700180856007800197 2008 eng d00aMercury Deposition in a Polar Desert Ecosystem0 aMercury Deposition in a Polar Desert Ecosystem a4710-47160 v421 aWitherow, R1 aLyons, Berry uhttps://mcm.lternet.edu/content/mercury-deposition-polar-desert-ecosystem00626nas a2200181 4500008004100000245008300041210006900124300001400193490000700207100002000214700001600234700001400250700001100264700002200275700002000297700001900317856010800336 2008 eng d00aMicrobial community composition in soils of Northern Victoria Land, Antarctica0 aMicrobial community composition in soils of Northern Victoria La a1713-17240 v101 aNiederberger, T1 aMcDonald, i1 aHacker, A1 aSoo, R1 aBarrett, John, E.1 aWall, Diana, H.1 aCary, Craig, S uhttps://mcm.lternet.edu/content/microbial-community-composition-soils-northern-victoria-land-antarctica00539nas a2200121 4500008004100000245009500041210006900136260002900205490001000234100002200244700003300266856011800299 2008 eng d00aMicrobial diversity and function at aquatic- terrestrial interfaces in desert ecosystems.0 aMicrobial diversity and function at aquatic terrestrial interfac bUniversity of New Mexico0 vPh.D.1 aZeglin, Lydia, H.1 aTakacs-Vesbach, Cristina, D. uhttps://mcm.lternet.edu/content/microbial-diversity-and-function-aquatic-terrestrial-interfaces-desert-ecosystems00539nas a2200145 4500008004100000245008300041210006900124300001200193490000700205100001200212700002000224700002000244700002300264856010600287 2007 eng d00aA mathematical model for variation in water-retention curves among sandy soils0 amathematical model for variation in waterretention curves among  a427-4360 v191 aHunt, H1 aTreonis, Amy, M1 aWall, Diana, H.1 aVirginia, Ross, A. uhttps://mcm.lternet.edu/content/mathematical-model-variation-water-retention-curves-among-sandy-soils00503nas a2200097 4500008004100000245013700041210006900178300001000247100002400257856012400281 2007 eng d00aMesoscale dynamics of ephemeral wetlands in the Antarctic Dry Valleys: Implications to production and distribution of organic matter0 aMesoscale dynamics of ephemeral wetlands in the Antarctic Dry Va a87-951 aMoorhead, Daryl, L. uhttps://mcm.lternet.edu/content/mesoscale-dynamics-ephemeral-wetlands-antarctic-dry-valleys-implications-production-and00558nas a2200145 4500008004100000245008500041210006900126490000800195100002700203700001500230700002200245700001800267700002100285856010600306 2007 eng d00aMetabolic activity and diversity of cryoconites in the Taylor Valley, Antarctica0 aMetabolic activity and diversity of cryoconites in the Taylor Va0 v1121 aForeman, Christine, M.1 aSattler, B1 aMikucki, Jill, A.1 aPorazinska, D1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/metabolic-activity-and-diversity-cryoconites-taylor-valley-antarctica00476nas a2200121 4500008004100000245007900041210006900120260002900189490000900218100001300227700002100240856009300261 2007 eng d00aMicrobial Processes in the Moats of Lakes in the Taylor Valley, Antarctica0 aMicrobial Processes in the Moats of Lakes in the Taylor Valley A bMontana State University0 vM.S.1 aMoore, J1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/microbial-processes-moats-lakes-taylor-valley-antarctica00592nas a2200145 4500008004100000245010200041210006900143490000700212100002700219700001600246700001700262700002300279700002100302856012300323 2006 eng d00aMeasuring ecosystem response in a rapidly changing environment: the Latitudinal Gradient Project0 aMeasuring ecosystem response in a rapidly changing environment t0 v101 aHoward-Williams, Clive1 aPeterson, D1 aLyons, Berry1 aCattaneo-Vietti, R1 aGordon, Shulamit uhttps://mcm.lternet.edu/content/measuring-ecosystem-response-rapidly-changing-environment-latitudinal-gradient-project02329nas a2200181 4500008004100000245009400041210006900135260004900204300000800253490000900261520166100270100002201931700001701953700002001970700002001990700002702010856011002037 2005 eng d00aMathematical Modeling of a Hydrocarbon Spill on the Ice Cover of Lake Fryxell, Antarctica0 aMathematical Modeling of a Hydrocarbon Spill on the Ice Cover of aColumbusbThe Ohio State Universityc06/2005 a1140 vM.S.3 a

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

1 aKarnovic, Marinko1 aLyons, Berry1 aCarey, Anne, E.1 aBair, Scott, E.1 avan der Veen, Cornelis uhttps://mcm.lternet.edu/content/mathematical-modeling-hydrocarbon-spill-ice-cover-lake-fryxell-antarctica00509nas a2200121 4500008004100000245009200041210006900133260003000202490000900232100001600241700001700257856011300274 2005 eng d00aMercury Concentrations in Snow and the Modern Mercury Flux to Taylor Valley, Antarctica0 aMercury Concentrations in Snow and the Modern Mercury Flux to Ta bThe Ohio State University0 vM.S.1 aWitherow, R1 aLyons, Berry uhttps://mcm.lternet.edu/content/mercury-concentrations-snow-and-modern-mercury-flux-taylor-valley-antarctica00454nas a2200121 4500008004100000245006100041210006100102260002900163490001000192100002200202700002100224856008700245 2005 eng d00aMicrobial Ecology of an Antarctic Subglacial Environment0 aMicrobial Ecology of an Antarctic Subglacial Environment bMontana State University0 vPh.D.1 aMikucki, Jill, A.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/microbial-ecology-antarctic-subglacial-environment00526nas a2200133 4500008004100000245008200041210006900123300001200192490000700204100002300211700002100234700002800255856010900283 2004 eng d00aMicroplankton dynamics in a perennially ice-covered Antarctic lake-Lake Hoare0 aMicroplankton dynamics in a perennially icecovered Antarctic lak a238-2490 v271 aRoberts, Emily, C.1 aPriscu, John, C.1 aLaybourn-Parry, Johanna uhttps://mcm.lternet.edu/content/microplankton-dynamics-perennially-ice-covered-antarctic-lake-lake-hoare00462nas a2200121 4500008004100000245007200041210006900113300001200182490000700194100001500201700002400216856010000240 2003 eng d00aMap-based methods for estimating glacier equilibrium-line altitudes0 aMapbased methods for estimating glacier equilibriumline altitude a329-3360 v491 aLeonard, K1 aFountain, Andrew, G uhttps://mcm.lternet.edu/content/map-based-methods-estimating-glacier-equilibrium-line-altitudes00452nas a2200121 4500008004100000245007700041210006900118300001000187490000600197100001200203700002000215856009500235 2002 eng d00aModeling the effects of loss of soil biodiversity on ecosystem function0 aModeling the effects of loss of soil biodiversity on ecosystem f a32-490 v81 aHunt, H1 aWall, Diana, H. uhttps://mcm.lternet.edu/content/modeling-effects-loss-soil-biodiversity-ecosystem-function00774nas a2200193 4500008004100000245014400041210006900185300001200254490000700266100001700273700002400290700002100314700002800335700002400363700002400387700002100411700002000432856012800452 2001 eng d00aThe McMurdo Dry Valleys Long-Term Ecological Research Program: new understanding of the biogeochemistry of the Dry Valley lakes: a review.0 aMcMurdo Dry Valleys LongTerm Ecological Research Program new und a202-2170 v251 aLyons, Berry1 aWelch, Kathleen, A.1 aPriscu, John, C.1 aLaybourn-Parry, Johanna1 aMoorhead, Daryl, L.1 aMcKnight, Diane, M.1 aDoran, Peter, T.1 aTranter, Martyn uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-long-term-ecological-research-program-new-understanding-biogeochemistry00770nas a2200193 4500008004100000245019000041210006900231300001400300490000700314100002300321700001500344700001400359700002100373700001600394700001300410700001500423700001700438856012100455 2001 eng d00aMineralogical and geochemical analyses of Antarctic lake sediments: A study of reflectanceand Mossbauer spectroscopy and C, N and S isotopes with applications for remote sensing on Mars0 aMineralogical and geochemical analyses of Antarctic lake sedimen a2875-28970 v651 aBishop, Janice, L.1 aLougear, A1 aNewton, J1 aDoran, Peter, T.1 aFroeschl, H1 aKrner, W1 aKoeberl, C1 aTrautwein, A uhttps://mcm.lternet.edu/content/mineralogical-and-geochemical-analyses-antarctic-lake-sediments-study-reflectanceand03621nas a2200133 4500008004100000245010500041210006900146260002700215490001000242520306700252100002503319700002403344856011903368 2001 eng d00aModeling hyporheic exchange influences on biogeochemical processes in dry valley streams, Antarctica0 aModeling hyporheic exchange influences on biogeochemical process bUniversity of Colorado0 vPh.D.3 a

The ephemeral streams of the Dry Valleys of Antarctica provide habitat to benthic algal mats, and greatly control the quantity and quality of glacial melt water that enters closed basin Dry Valley lakes. Dry Valley watersheds are composed of streambeds and adjacent hyporheic zones. Hydrologic exchange of water and solutes between the stream and the hyporheic zone has the overall effect of increasing residence time in the stream/hyporheic system. Biogeochemical reactions (e.g. chemical weathering, nutrient assimilation) occur both in the water column and in the hyporheic zone. Field experiments and solute transport modeling were employed to elucidate the effects of rapid hyporheic exchange on biogeochemical cycling in Antarctic streams. The results presented here show that (1) large portions of the wetted zone that surrounds each stream is a hyporheic zone, and that stream water exchanges into and out of extended portions of this zone on the order of weeks, (2) the rapid exchange of stream water between the water column and the hyporheic zone controls the rate of weathering in streambed sediments, and (3) denitrification in streams is limited by the conversion of NO2 to N2O, while the conversion of NO3 to NO2 occurs very quickly.

1 aGooseff, Michael, N.1 aMcKnight, Diane, M. uhttps://mcm.lternet.edu/content/modeling-hyporheic-exchange-influences-biogeochemical-processes-dry-valley-streams00606nas a2200157 4500008004100000245008300041210006900124260001700193100002800210700002300238700002100261700002700282700001700309700001500326856010700341 2000 eng d00aMixotrophy as a survival strategy among planktonic protozoa in Antarctic lakes0 aMixotrophy as a survival strategy among planktonic protozoa in A bCaxton Press1 aLaybourn-Parry, Johanna1 aRoberts, Emily, C.1 aBell, Elanor, R.1 aHoward-Williams, Clive1 aDavidson, W.1 aBroady, P. uhttps://mcm.lternet.edu/content/mixotrophy-survival-strategy-among-planktonic-protozoa-antarctic-lakes00514nas a2200109 4500008004100000245006200041210006000103260010700163100002400270700002100294856008900315 1999 eng d00aMcMurdo Dry Valley Lakes: Impacts of Research Activities.0 aMcMurdo Dry Valley Lakes Impacts of Research Activities bDesert Research Institute, University and Community College System of Nevada, USA, special publication1 aWharton, Robert, A.1 aDoran, Peter, T. uhttps://mcm.lternet.edu/content/mcmurdo-dry-valley-lakes-impacts-research-activities00523nas a2200121 4500008004100000245011300041210006900154300001200223490000700235100001500242700002400257856012000281 1999 eng d00aMcMurdo LTER: Photosynthesis in an extreme shade habitat: benthic microbial mats from Lake Hoare, Antarctica0 aMcMurdo LTER Photosynthesis in an extreme shade habitat benthic  a448-4590 v351 aHawes, Ian1 aSchwarz, Anne-Maree uhttps://mcm.lternet.edu/content/mcmurdo-lter-photosynthesis-extreme-shade-habitat-benthic-microbial-mats-lake-hoare00424nas a2200133 4500008004100000245004500041210004500086300001400131490000700145100001700152700002400169700002600193856007100219 1999 eng d00aMercury in aquatic systems in Antarctica0 aMercury in aquatic systems in Antarctica a2235-22380 v261 aLyons, Berry1 aWelch, Kathleen, A.1 aBonzongo, Jean-Claude uhttps://mcm.lternet.edu/content/mercury-aquatic-systems-antarctica00498nas a2200121 4500008004100000245008700041210006900128300001200197490000700209100002300216700002800239856010900267 1999 eng d00aMixotrophic cryptophytes and their predators in the Dry Valley lakes of Antarctica0 aMixotrophic cryptophytes and their predators in the Dry Valley l a737-7450 v411 aRoberts, Emily, C.1 aLaybourn-Parry, Johanna uhttps://mcm.lternet.edu/content/mixotrophic-cryptophytes-and-their-predators-dry-valley-lakes-antarctica00576nas a2200121 4500008004100000245015400041210006900195300001200264490000700276100002400283700002100307856012600328 1998 eng d00aThe McMurdo Dry Valley Ecosystem: Organization, Controls, and Linkages, in Ecosystem Processes in a Polar Desert: The McMurdo Dry Valleys, Antarctica0 aMcMurdo Dry Valley Ecosystem Organization Controls and Linkages  a351-3630 v721 aMoorhead, Daryl, L.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/mcmurdo-dry-valley-ecosystem-organization-controls-and-linkages-ecosystem-processes-polar00531nas a2200121 4500008004100000245010700041210006900148300001200217490000700229100003000236700002400266856011900290 1998 eng d00aMcMurdo Dry Valleys Long-Term Ecological Research (LTER): An overview of 1995-1996 research activities0 aMcMurdo Dry Valleys LongTerm Ecological Research LTER An overvie a187-1880 v311 aJennings-Mays, Sherry, E.1 aWharton, Robert, A. uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-long-term-ecological-research-lter-overview-1995-1996-research00543nas a2200121 4500008004100000245012700041210006900168300001200237490000700249100001700256700002400273856012400297 1998 eng d00aMcMurdo Dry Valleys LTER: Characterization of protozoan communities in lakes Hoare and Fryxell using artificial substrates0 aMcMurdo Dry Valleys LTER Characterization of protozoan communiti a201-2020 v311 aKepner, R.L.1 aWharton, Robert, A. uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-lter-characterization-protozoan-communities-lakes-hoare-and-fryxell00509nas a2200145 4500008004100000245006800041210006400109300000800173490000700181100001700188700002400205700002100229700001900250856009400269 1998 eng d00aMcMurdo Dry Valleys LTER: Density-driven mixing in Lake Hoare?0 aMcMurdo Dry Valleys LTER Densitydriven mixing in Lake Hoare a2050 v311 aLyons, Berry1 aWelch, Kathleen, A.1 aTyler, Scott, W.1 aSharma, Pankaj uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-lter-density-driven-mixing-lake-hoare00599nas a2200145 4500008004100000245010700041210006900148300001200217490000700229100002600236700002400262700002300286700001900309856012500328 1998 eng d00aMcMurdo Dry Valleys LTER: Genetic diversity of soil nematodes in the McMurdo Dry Valleys of Antarctica0 aMcMurdo Dry Valleys LTER Genetic diversity of soil nematodes in  a203-2040 v311 aCourtright, Ericha, M1 aFreckman, Diana, W.1 aVirginia, Ross, A.1 aThomas, Kelley uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-lter-genetic-diversity-soil-nematodes-mcmurdo-dry-valleys-antarctica00591nas a2200145 4500008004100000245010800041210006900149260001200218300001200230490000700242100002100249700002400270700002400294856012700318 1998 eng d00aMcMurdo Dry Valleys LTER: Geophysical determination of bathymetry and morphology of Taylor Valley lakes0 aMcMurdo Dry Valleys LTER Geophysical determination of bathymetry c01/1996 a198-2000 v311 aDoran, Peter, T.1 aWharton, Robert, A.1 aSchmok, Jeffrey, P. uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-lter-geophysical-determination-bathymetry-and-morphology-taylor-valley00538nas a2200121 4500008004100000245012400041210006900165300001200234490000700246100001900253700002100272856012300293 1998 eng d00aMcMurdo Dry Valleys LTER: Phosphorus deficiency and alkaline phosphatase activity in lakes of Taylor Valley, Antarctica0 aMcMurdo Dry Valleys LTER Phosphorus deficiency and alkaline phos a206-2080 v311 aDore, John, E.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-lter-phosphorus-deficiency-and-alkaline-phosphatase-activity-lakes00529nas a2200133 4500008004100000245008700041210006900128300001200197490000700209100002000216700002400236700002400260856011100284 1998 eng d00aMcMurdo Dry Valleys LTER: Solar radiation on glaciers in Taylor Valley, Antarctica0 aMcMurdo Dry Valleys LTER Solar radiation on glaciers in Taylor V a191-1930 v311 aDana, Gayle, L.1 aWharton, Robert, A.1 aFountain, Andrew, G uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-lter-solar-radiation-glaciers-taylor-valley-antarctica00554nas a2200133 4500008004100000245010100041210006900142300001200211490000700223100002400230700002100254700002000275856012500295 1998 eng d00aMcMurdo Dry Valleys LTER: Spatial variation of glacier mass balance in Taylor Valley, Antarctica0 aMcMurdo Dry Valleys LTER Spatial variation of glacier mass balan a194-1950 v311 aFountain, Andrew, G1 aLewis, Karen, J.1 aDana, Gayle, L. uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-lter-spatial-variation-glacier-mass-balance-taylor-valley-antarctica00566nas a2200121 4500008004100000245014700041210006900188300001200257490000700269100002400276700002400300856012000324 1998 eng d00aMcMurdo Dry Valleys LTER: Stream discharge as a function of ambient temperature and incoming shortwave radiation in Taylor Valley, Antarctica0 aMcMurdo Dry Valleys LTER Stream discharge as a function of ambie a196-1970 v311 aMoorhead, Daryl, L.1 aMcKnight, Diane, M. uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-lter-stream-discharge-function-ambient-temperature-and-incoming00552nas a2200133 4500008004100000245010300041210006900144300001200213490000700225100002100232700002400253700001900277856012200296 1998 eng d00aMcMurdo Dry Valleys LTER: The role of terminus cliff melt in streamflow, Taylor Valley, Antarctica0 aMcMurdo Dry Valleys LTER The role of terminus cliff melt in stre a189-1900 v311 aLewis, Karen, J.1 aFountain, Andrew, G1 aLangevin, Paul uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-lter-role-terminus-cliff-melt-streamflow-taylor-valley-antarctica00602nas a2200145 4500008004100000245012200041210006900163300001200232490000800244100001700252700001600269700002400285700001900309856012800328 1998 eng d00aMercury speciation and distribution in a polar desert lake (Lake Hoare, Antarctica) and two glacial meltwater streams0 aMercury speciation and distribution in a polar desert lake Lake  a229-2370 v2131 aVandal, G.M.1 aMason, R.P.1 aMcKnight, Diane, M.1 aFitzgerald, W. uhttps://mcm.lternet.edu/content/mercury-speciation-and-distribution-polar-desert-lake-lake-hoare-antarctica-and-two-glacial00567nas a2200121 4500008004100000245015200041210006900193300001200262490000700274100002000281700002100301856012300322 1998 eng d00aMicrobial phototrophic, heterotrophic, and diazotrophic activities associated with aggregates in the permanent ice cover of Lake Bonney, Antarctica0 aMicrobial phototrophic heterotrophic and diazotrophic activities a221-2300 v361 aPaerl, Hans, W.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/microbial-phototrophic-heterotrophic-and-diazotrophic-activities-associated-aggregates00608nas a2200133 4500008004100000245015100041210006900192300001200261490000700273100002400280700002400304700002000328856012600348 1998 eng d00aModeling Nitrogen Transformations in Dry Valley Streams, Antarctica, in Ecosystem Processes in a Polar Desert: The McMurdo Dry Valleys, Antarctica0 aModeling Nitrogen Transformations in Dry Valley Streams Antarcti a141-1510 v721 aMoorhead, Daryl, L.1 aMcKnight, Diane, M.1 aTate, Cathy, M. uhttps://mcm.lternet.edu/content/modeling-nitrogen-transformations-dry-valley-streams-antarctica-ecosystem-processes-polar00387nas a2200073 4500008004100000245009500041210006900136856010800205 1997 eng d00aThe measurement of reactive silicate in saline-hypersaline lakes: examples of the problem0 ameasurement of reactive silicate in salinehypersaline lakes exam uhttps://mcm.lternet.edu/content/measurement-reactive-silicate-saline-hypersaline-lakes-examples-problem00462nas a2200145 4500008004100000245004200041210003800083260002900121300001200150100002800162700001700190700002700207700001500234856006700249 1997 eng d00aThe microbial loop in Antarctic lakes0 amicrobial loop in Antarctic lakes aRotterdambBalkema Press a231-2401 aLaybourn-Parry, Johanna1 aLyons, Berry1 aHoward-Williams, Clive1 aHawes, Ian uhttps://mcm.lternet.edu/content/microbial-loop-antarctic-lakes00675nas a2200169 4500008004100000245011500041210006900156300001000225490000700235100002800242700002000270700002400290700002100314700002500335700001900360856012600379 1997 eng d00aThe microbial plankton of Lake Fryxell, southern Victoria Land, Antarctica during the summers of 1992 and 19940 amicrobial plankton of Lake Fryxell southern Victoria Land Antarc a54-610 v171 aLaybourn-Parry, Johanna1 aJames, Mark, R.1 aMcKnight, Diane, M.1 aPriscu, John, C.1 aSpaulding, Sarah, A.1 aShiel, Russell uhttps://mcm.lternet.edu/content/microbial-plankton-lake-fryxell-southern-victoria-land-antarctica-during-summers-1992-and00623nas a2200157 4500008004100000245009800041210006900139300001200208490000700220100002000227700002500247700001800272700002300290700002400313856012800337 1996 eng d00aMicrocosms and Soil Ecology: Critical Linkages Between Field Studies and Modelling Food Webs0 aMicrocosms and Soil Ecology Critical Linkages Between Field Stud a694-7050 v771 aMoore, John, C.1 aDe Ruiter, Peter, C.1 aHunt, William1 aColeman, David, C.1 aFreckman, Diana, W. uhttps://mcm.lternet.edu/content/microcosms-and-soil-ecology-critical-linkages-between-field-studies-and-modelling-food-webs00489nas a2200109 4500008004100000245010700041210006900148300001200217490000700229100002400236856011900260 1995 eng d00aMcMurdo Dry Valleys Long-Term Ecological Research (LTER): An overview of 1994-1995 research activities0 aMcMurdo Dry Valleys LongTerm Ecological Research LTER An overvie a275-2760 v301 aWharton, Robert, A. uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-long-term-ecological-research-lter-overview-1994-1995-research00596nas a2200145 4500008004100000245010000041210006900141300001200210490000700222100002100229700002000250700002900270700002400299856012700323 1995 eng d00aMcMurdo Dry Valleys Long-Term Ecological Research (LTER): LTER automatic weather network (LAWN)0 aMcMurdo Dry Valleys LongTerm Ecological Research LTER LTER autom a276-2800 v301 aDoran, Peter, T.1 aDana, Gayle, L.1 aHastings, Jordan, Towner1 aWharton, Robert, A. uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-long-term-ecological-research-lter-lter-automatic-weather-network-lawn00539nas a2200121 4500008004100000245012300041210006900164300001200233490000700245100002400252700002000276856012100296 1995 eng d00aMcMurdo LTER: Algal mat distribution in glacial meltwater streams in Taylor Valley, southern Victoria Land, Antarctica0 aMcMurdo LTER Algal mat distribution in glacial meltwater streams a287-2890 v301 aMcKnight, Diane, M.1 aTate, Cathy, M. uhttps://mcm.lternet.edu/content/mcmurdo-lter-algal-mat-distribution-glacial-meltwater-streams-taylor-valley-southern00483nas a2200121 4500008004100000245008600041210006900127300001200196490000700208100002400215700001700239856010500256 1995 eng d00aMcMurdo LTER: Comparative limnology of the Taylor Valley lakes: The major solutes0 aMcMurdo LTER Comparative limnology of the Taylor Valley lakes Th a292-2930 v301 aWelch, Kathleen, A.1 aLyons, Berry uhttps://mcm.lternet.edu/content/mcmurdo-lter-comparative-limnology-taylor-valley-lakes-major-solutes00496nas a2200121 4500008004100000245009200041210006900133300001200202490000700214100001500221700002400236856011400260 1995 eng d00aMcMurdo LTER: Photosynthesis in benthic cyanobacterial mats from Lake Hoare, Antarctica0 aMcMurdo LTER Photosynthesis in benthic cyanobacterial mats from  a296-2970 v301 aHawes, Ian1 aSchwarz, Anne-Maree uhttps://mcm.lternet.edu/content/mcmurdo-lter-photosynthesis-benthic-cyanobacterial-mats-lake-hoare-antarctica00450nas a2200109 4500008004100000245008000041210006900121300001200190490000700202100002900209856010200238 1995 eng d00aMcMurdo LTER: Progress with the Taylor Valley geographic information system0 aMcMurdo LTER Progress with the Taylor Valley geographic informat a297-2990 v301 aHastings, Jordan, Towner uhttps://mcm.lternet.edu/content/mcmurdo-lter-progress-taylor-valley-geographic-information-system00564nas a2200121 4500008004100000245014800041210006900189300001200258490000700270100002000277700002100297856012400318 1995 eng d00aMcMurdo LTER: Relationships between vertical nutrient flux and phytoplankton biomass and productivity in lakes of the Taylor Valley, Antarctica0 aMcMurdo LTER Relationships between vertical nutrient flux and ph a294-2950 v301 aEdwards, R., L.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/mcmurdo-lter-relationships-between-vertical-nutrient-flux-and-phytoplankton-biomass-and00616nas a2200145 4500008004100000245013100041210006900172300001200241490000700253100002200260700002400282700001600306700002300322856012500345 1995 eng d00aMcMurdo LTER: Soil properties associated with nematode distribution along an elevational transect in Taylor Valley, Antarctica0 aMcMurdo LTER Soil properties associated with nematode distributi a282-2830 v301 aPowers, Laura, E.1 aFreckman, Diana, W.1 aHo, Mengchi1 aVirginia, Ross, A. uhttps://mcm.lternet.edu/content/mcmurdo-lter-soil-properties-associated-nematode-distribution-along-elevational-transect00613nas a2200145 4500008004100000245011900041210006900160300001200229490000700241100002500248700002500273700002100298700002400319856012400343 1995 eng d00aMcMurdo LTER: Species composition and spatial distribution of algal mats in Green Creek, Taylor Valley, Antarctica0 aMcMurdo LTER Species composition and spatial distribution of alg a289-2910 v301 aAlger, Alexander, S.1 aSpaulding, Sarah, A.1 aShupe, Gordon, H1 aMcKnight, Diane, M. uhttps://mcm.lternet.edu/content/mcmurdo-lter-species-composition-and-spatial-distribution-algal-mats-green-creek-taylor00544nas a2200145 4500008004100000245008200041210006900123300001200192490000700204100002100211700002000232700002100252700002400273856010100297 1995 eng d00aMcMurdo LTER: The surface-energy balance of the Canada Glacier, Taylor Valley0 aMcMurdo LTER The surfaceenergy balance of the Canada Glacier Tay a280-2820 v301 aLewis, Karen, J.1 aDana, Gayle, L.1 aTyler, Scott, W.1 aFountain, Andrew, G uhttps://mcm.lternet.edu/content/mcmurdo-lter-surface-energy-balance-canada-glacier-taylor-valley00439nas a2200109 4500008004100000245007600041210006900117300001200186490000700198100002400205856010000229 1994 eng d00aMcMurdo Dry Valleys LTER: An overview of 1993-1994 research activities0 aMcMurdo Dry Valleys LTER An overview of 19931994 research activi a224-2260 v291 aWharton, Robert, A. uhttps://mcm.lternet.edu/content/mcmurdo-dry-valleys-lter-overview-1993-1994-research-activities00478nas a2200121 4500008004100000245007500041210006900116300001200185490000700197100002900204700001900233856010400252 1994 eng d00aMcMurdo LTER: Developing a geographic information system access system0 aMcMurdo LTER Developing a geographic information system access s a246-2470 v291 aHastings, Jordan, Towner1 aButt, Anya, Z. uhttps://mcm.lternet.edu/content/mcmurdo-lter-developing-geographic-information-system-access-system00468nas a2200121 4500008004100000245007000041210006900111300001200180490000700192100001900199700002900218856009900247 1994 eng d00aMcMurdo LTER: Developing a geographic information system database0 aMcMurdo LTER Developing a geographic information system database a244-2450 v291 aButt, Anya, Z.1 aHastings, Jordan, Towner uhttps://mcm.lternet.edu/content/mcmurdo-lter-developing-geographic-information-system-database00492nas a2200133 4500008004100000245006900041210006700110300001200177490000700189100002400196700002200220700002000242856009600262 1994 eng d00aMcMurdo LTER: Glacier mass balances of Taylor Valley, Antarctica0 aMcMurdo LTER Glacier mass balances of Taylor Valley Antarctica a226-2280 v291 aFountain, Andrew, G1 aVaughn, Bruce, H.1 aDana, Gayle, L. uhttps://mcm.lternet.edu/content/mcmurdo-lter-glacier-mass-balances-taylor-valley-antarctica00688nas a2200181 4500008004100000245010100041210006900142300001200211490000700223100002400230700001700254700002100271700002000292700002400312700002200336700002400358856012400382 1994 eng d00aMcMurdo LTER: Inorganic geochemical studies with special reference to calcium carbonate dynamics0 aMcMurdo LTER Inorganic geochemical studies with special referenc a237-2390 v291 aWelch, Kathleen, A.1 aLyons, Berry1 aPriscu, John, C.1 aEdwards, R., L.1 aMcKnight, Diane, M.1 aHouse, Harold, R.1 aWharton, Robert, A. uhttps://mcm.lternet.edu/content/mcmurdo-lter-inorganic-geochemical-studies-special-reference-calcium-carbonate-dynamics00506nas a2200145 4500008004100000245006200041210006000103300001200163490000700175100002100182700002400203700002500227700001900252856008900271 1994 eng d00aMcMurdo LTER: Paleolimnology of Taylor Valley, Antarctica0 aMcMurdo LTER Paleolimnology of Taylor Valley Antarctica a234-2370 v291 aDoran, Peter, T.1 aWharton, Robert, A.1 aSpaulding, Sarah, A.1 aFoster, J., S. uhttps://mcm.lternet.edu/content/mcmurdo-lter-paleolimnology-taylor-valley-antarctica00468nas a2200109 4500008004100000245009400041210006900135300001200204490000700216100002100223856011400244 1994 eng d00aMcMurdo LTER: Phytoplankton nutrient deficiency in lakes of the Taylor Valley, Antarctica0 aMcMurdo LTER Phytoplankton nutrient deficiency in lakes of the T a239-2410 v291 aPriscu, John, C. uhttps://mcm.lternet.edu/content/mcmurdo-lter-phytoplankton-nutrient-deficiency-lakes-taylor-valley-antarctica00513nas a2200121 4500008004100000245009500041210006900136300001200205490000700217100002400224700002400248856011900272 1994 eng d00aMcMurdo LTER: Primary production model of benthic microbial mats in Lake Hoare, Antarctica0 aMcMurdo LTER Primary production model of benthic microbial mats  a241-2430 v291 aMoorhead, Daryl, L.1 aWharton, Robert, A. uhttps://mcm.lternet.edu/content/mcmurdo-lter-primary-production-model-benthic-microbial-mats-lake-hoare-antarctica00465nas a2200133 4500008004100000245005900041210005800100300001200158490000700170100002400177700002200201700002100223856008700244 1994 eng d00aMcMurdo LTER: Streamflow Measurements in Taylor Valley0 aMcMurdo LTER Streamflow Measurements in Taylor Valley a230-2320 v291 aMcKnight, Diane, M.1 aHouse, Harold, R.1 aVon Gerard, Paul uhttps://mcm.lternet.edu/content/mcmurdo-lter-streamflow-measurements-taylor-valley00562nas a2200133 4500008004100000245011400041210006900155300001200224490000700236100002000243700002000263700002200283856012300305 1994 eng d00aMcMurdo LTER: Using narrow band spectroradiometry to assess algal and moss communities in a dry valley stream0 aMcMurdo LTER Using narrow band spectroradiometry to assess algal a232-2340 v291 aDana, Gayle, L.1 aTate, Cathy, M.1 aDewey, Sharon, L. uhttps://mcm.lternet.edu/content/mcmurdo-lter-using-narrow-band-spectroradiometry-assess-algal-and-moss-communities-dry00587nas a2200145 4500008004100000245010700041210006900148300001200217490000700229100002200236700002400258700001600282700002300298856012000321 1994 eng d00aMcMurdo LTER:Soil and nematode distribution along an elevational gradient in Taylor Valley, Antarctica0 aMcMurdo LTERSoil and nematode distribution along an elevational  a228-2290 v291 aPowers, Laura, E.1 aFreckman, Diana, W.1 aHo, Mengchi1 aVirginia, Ross, A. uhttps://mcm.lternet.edu/content/mcmurdo-ltersoil-and-nematode-distribution-along-elevational-gradient-taylor-valley00549nas a2200121 4500008004100000245013900041210006900180300001200249490000700261100001900268700002100287856011900308 1993 eng d00aMicrobial communities in the permanent ice cap of Lake Bonney, Antarctica: Relationships among chlorophyll-a , gravel, and nutrients.0 aMicrobial communities in the permanent ice cap of Lake Bonney An a247-2490 v281 aWing, Kate, T.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/microbial-communities-permanent-ice-cap-lake-bonney-antarctica-relationships-among00508nas a2200121 4500008004100000245009400041210006900135300001200204490000700216100002100223700002100244856012100265 1993 eng d00aMicrobial respiration potential in Lake Bonney using a novel tetrazolium-reduction method0 aMicrobial respiration potential in Lake Bonney using a novel tet a244-2450 v281 aSmith, James, J.1 aPriscu, John, C. uhttps://mcm.lternet.edu/content/microbial-respiration-potential-lake-bonney-using-novel-tetrazolium-reduction-method00340nas a2200097 4500008004100000245004900041210004800090260001200138100002400150856006800174 1991 eng d00aMcMurdo Dry Valleys: A cold desert ecosystem0 aMcMurdo Dry Valleys A cold desert ecosystem c10/19911 aWharton, Robert, A. uhttps://mcm.lternet.edu/sites/default/files/MCM_1991_Report.pdf