@article {4940, title = {McMurdo Dry Valley lake edge {\textquoteleft}moats{\textquoteright}: The ecological intersection between terrestrial and aquatic polar desert habitat}, journal = {Antarctic Science}, year = {2024}, month = {04/2024}, pages = {1 - 17}, abstract = {

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

}, keywords = {LTER-MCM, connectivity, ecosystem, ice, microbial mats, transition}, issn = {0954-1020}, doi = {10.1017/S0954102024000087}, url = {https://www.cambridge.org/core/journals/antarctic-science/article/mcmurdo-dry-valley-lake-edge-moats-the-ecological-intersection-between-terrestrial-and-aquatic-polar-desert-habitats/31D94DD51E651603482A3AE6E8A52A57}, author = {Stone, Michael S. and Devlin, Shawn and Ian Hawes and Kathleen A. Welch and Michael N. Gooseff and Cristina D. Takacs-Vesbach and Rachael M. Morgan-Kiss and Byron Adams and John E. Barrett and John C. Priscu and Peter T. Doran} } @article {4844, title = {Causes and characteristics of electrical resistivity variability in shallow (<4 m) soils in Taylor Valley, East Antarctica}, journal = {Journal of Geophysical Research: Earth Surface}, volume = {128}, year = {2023}, month = {02/2023}, pages = {e2022JF006696}, abstract = {

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

}, keywords = {LTER-MCM, active layer, airborne electromagnetic surveys, McMurdo Dry Valleys, permafrost dynamics}, issn = {2169-9003}, doi = {10.1029/2022JF006696}, url = {https://onlinelibrary.wiley.com/doi/10.1029/2022JF006696}, author = {Gutterman, William S. and Peter T. Doran and Ross A. Virginia and John E. Barrett and Myers, Krista F. and Tulaczyk, Slawek M. and Foley, Neil T. and Jill A. Mikucki and Hilary A. Dugan and Grombacher, Denys and Bording, Thue S. and Auken, E.} } @article {4843, title = {Extreme cold (-69.1{\textdegree}C) in the McMurdo Dry Valleys}, journal = {Antarctic Science}, volume = {30}, year = {2023}, month = {03/2023}, pages = {1-4}, keywords = {LTER-MCM, climate, extreme, meteorology, temperature, weather}, issn = {0954-1020}, doi = {10.1017/S0954102022000451}, url = {https://www.cambridge.org/core/journals/antarctic-science/article/extreme-cold-691c-in-the-mcmurdo-dry-valleys/3516874750E5EF96365A26E8D49CA4EC}, author = {Peter T. Doran and Myers, Krista F. and Christopher P. McKay and David Bromwich} } @article {4714, title = {Barotropic seiches in a perennially ice-covered lake, East Antarctica}, journal = {Limnology and Oceanography Letters}, volume = {7}, year = {2022}, month = {02/2022}, pages = {26 - 33}, abstract = {

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

}, keywords = {LTER-MCM}, issn = {2378-2242}, doi = {10.1002/lol2.10226}, url = {https://aslopubs.onlinelibrary.wiley.com/doi/10.1002/lol2.10226}, author = {Castendyk, Devin and Hilary A. Dugan and Gallagher, Hugh A. and Pujara, Nimish and Peter T. Doran and John C. Priscu and W. Berry Lyons} } @article {4818, title = {Cross-site comparisons of dryland ecosystem response to climate change in the US Long-Term Ecological Research Network}, journal = {BioScience}, year = {2022}, month = {08/2022}, abstract = {

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

}, keywords = {LTER-MCM, ANPP, climate change, Disturbance, drought, LTER, wildfire}, issn = {0006-3568}, doi = {10.1093/biosci/biab134}, url = {https://academic.oup.com/bioscience/advance-article/doi/10.1093/biosci/biab134/6654840}, author = {Hudson, Amy R. and Debra P. C. Peters and J.M. Blair and Childers, Daniel L. and Peter T. Doran and Geil, Kerrie and Michael N. Gooseff and Gross, Katherine L. and Haddad, Nick M. and Pastore, Melissa A. and Rudgers, Jennifer A. and Osvaldo E. Sala and Seabloom, Eric W. and Shaver, Gaius} } @article {4823, title = {Valley-floor snowfall in Taylor Valley, Antarctica, from 1995 to 2017: Spring, summer and autumn}, journal = {Antarctic Science}, volume = {34}, year = {2022}, month = {08/2022}, pages = {325-335}, abstract = {

We present an analysis of the 20 year snowfall dataset in Taylor Valley and the results of a new snow cover monitoring study. Snowfall has been measured at four sites in Taylor Valley from 1995 to 2017. We focus on valley-floor snowfall when wind does not exceed 5 m s-1, and we exclude winter from our analysis due to poor data quality. Snowfall averaged 11 mm water equivalent (w.e.) from 1995 to 2017 across all stations and ranged from 1 to 58 mm w.e. Standard deviations ranged from 3 to 17 mm w.e., highlighting the strong interannual variability of snowfall in Taylor Valley. During spring and autumn there is a spatial gradient in snowfall such that the coast received twice as much snowfall as more central and inland stations. We identified a changepoint in 2007 from increasing snowfall (3 mm w.e. yr-1) to decreasing snowfall (1 mm w.e. yr-1), which coincides with a shift from decreasing temperature to no detectable temperature trend. Daily camera imagery from 2007 to 2017 augments the snowfall measurements. The camera imagery revealed a near tripling of the average number of days with snow cover from 37 days between 2006 and 2012 to 106 days with snow cover between 2012 and 2017.

}, keywords = {LTER-MCM, automated weather station, camera, McMurdo Dry Valleys, snow cover, snow persistence}, doi = {10.1017/S0954102022000256}, url = {https://www.cambridge.org/core/product/identifier/S0954102022000256/type/journal_article}, author = {Myers, Madeline and Peter T. Doran and Myers, Krista F.} } @article {4732, title = {The magnitude and climate sensitivity of isotopic fractionation from ablation of Antarctic Dry Valley lakes}, journal = {Arctic, Antarctic, and Alpine Research}, volume = {53}, year = {2021}, month = {12/2021}, pages = {352 - 371}, abstract = {

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.

}, keywords = {LTER-MCM, Dry Valley lakes, isotope fractionation, stable water isotopes}, issn = {1523-0430}, doi = {10.1080/15230430.2021.2001899}, url = {https://www.tandfonline.com/doi/full/10.1080/15230430.2021.2001899}, author = {Bellagamba, Anthony W. and Berkelhammer, Max and Winslow, Luke A. and Peter T. Doran and Myers, Krista F. and Devlin, Shawn and Ian Hawes} } @article {4597, title = {Metabolic capacity of the Antarctic cyanobacterium Phormidium pseudopriestleyi that sustains oxygenic photosynthesis in the presence of hydrogen sulfide}, journal = {Genes}, volume = {12}, year = {2021}, month = {03/2021}, pages = {426}, abstract = {

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.\ 

}, keywords = {LTER-MCM}, doi = {10.3390/genes12030426}, url = {https://www.mdpi.com/2073-4425/12/3/426}, author = {Lumian, Jessica E. and Jungblut, Anne D. and Dillon, Megan L. and Hawes, Ian and Peter T. Doran and Mackey, Tyler J. and Dick, Gregory J. and Grettenberger, Christen L. and Sumner, Dawn Y.} } @article {4647, title = {Thermal legacy of a large paleolake in Taylor Valley, East Antarctica, as evidenced by an airborne electromagnetic survey}, journal = {The Cryosphere}, volume = {15}, year = {2021}, month = {08/2021}, pages = {3577 - 3593}, abstract = {

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

}, keywords = {LTER-MCM}, doi = {10.5194/tc-15-3577-2021}, url = {https://tc.copernicus.org/articles/15/3577/2021/}, author = {Myers, Krista F. and Peter T. Doran and Tulaczyk, Slawek M. and Foley, Neil T. and Bording, Thue S. and Auken, Esben and Hilary A. Dugan and Jill A. Mikucki and Foged, Nikolaj and Grombacher, Denys and Ross A. Virginia} } @article {4613, title = {Year-round and long-term phytoplankton dynamics in Lake Bonney, a permanently ice-covered Antarctic lake}, journal = {Journal of Geophysical Research: Biogeosciences}, volume = {126}, year = {2021}, month = {04/2021}, pages = {e2020JG005925}, abstract = {

Lake Bonney (McMurdo Dry Valleys, east Antarctica) represents a year-round refugium for life adapted to permanent extreme conditions. Despite intensive research since the 1960s, due to the logistical constraints posed by 4-months of 24-h darkness, knowledge of how the resident photosynthetic microorganisms respond to the polar winter is limited. In addition, the lake level has risen by more than 3 m since 2004: impacts of rapid lake level rise on phytoplankton community structure is also poorly understood. From 2004 to 2015 an in situ submersible spectrofluorometer (bbe FluoroProbe) was deployed in Lake Bonney during the austral summer to quantify the vertical structure of four functional algal groups (green algae, mixed algae, and cryptophytes, cyanobacteria). During the 2013\–2014 field season the Fluoroprobe was mounted on autonomous cable-crawling profilers deployed in both the east and west lobes of Lake Bonney, obtaining the first daily phytoplankton profiles through the polar night. Our findings showed that phytoplankton communities were differentially impacted by physical and chemical factors over long-term versus seasonal time scales. Following a summer of rapid lake level rise (2010\–2011), an increase in depth integrated chlorophyll a (chl-a) occurred in Lake Bonney caused by stimulation of photoautotrophic green algae. Conversely, peaks in chl-a during the polar night were associated with an increase in mixotrophic haptophytes and cryptophytes. Collectively our data reveal that phytoplankton groups possessing variable trophic abilities are differentially competitive during seasonal and long-term time scales owing to periods of higher nutrients (photoautotrophs) versus light/energy limitation (mixotrophs).

}, keywords = {LTER-MCM, algae, Antarctic, fluorometry, ice, lakes, light, profiling, winter}, issn = {2169-8953}, doi = {10.1029/2020JG005925}, url = {https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JG005925}, author = {Patriarche, Jeffrey D. and John C. Priscu and Cristina D. Takacs-Vesbach and Winslow, Luke A. and Myers, Krista F. and Heather N. Buelow and Rachael M. Morgan-Kiss and Peter T. Doran} } @article {4395, title = {Energetic and environmental constraints on the community structure of benthic microbial mats in Lake Fryxell, Antarctica}, journal = {FEMS Microbiology Ecology}, volume = {96}, year = {2020}, month = {02/2020}, abstract = {

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

}, keywords = {LTER-MCM, Antarctica, energy, Lake Fryxell, microbial mat, Oxygen, Photosynthetically Active Radiation}, doi = {10.1093/femsec/fiz207}, url = {https://academic.oup.com/femsec/article/96/2/fiz207/5697196}, author = {Dillon, Megan L. and Ian Hawes and Jungblut, Anne D. and Mackey, Tyler J. and Eisen, Jonathan A. and Peter T. Doran and Sumner, Dawn Y.} } @article {4582, title = {Environmental control on the distribution of metabolic strategies of benthic microbial mats in Lake Fryxell, Antarctica}, journal = {PLoS ONE}, volume = {15}, year = {2020}, month = {04/2020}, pages = {e0231053}, abstract = {

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

}, keywords = {LTER-MCM}, doi = {10.1371/journal.pone.0231053}, url = {https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0231053}, author = {Dillon, Megan L. and Hawes, Ian and Jungblut, Anne D. and Mackey, Tyler J. and Eisen, Jonathan A. and Peter T. Doran and Sumner, Dawn Y.} } @article {4418, title = {GIS tool to predict photosynthetically active radiation in a Dry Valley}, journal = {Antarctic Science}, year = {2020}, month = {04/2020}, abstract = {

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

}, keywords = {LTER-MCM, ArcMap, automated weather station, digital elevation model, ice-covered lakes, McMurdo Dry Valleys, R model, Taylor Valley}, doi = {10.1017/S0954102020000218}, url = {https://www.cambridge.org/core/journals/antarctic-science/article/gis-tool-to-predict-photosynthetically-active-radiation-in-a-dry-valley/BD0BE4FF6A8F3DAAF32D698797287078}, author = {Acosta, Dimitri R. and Peter T. Doran and Myers, Madeline} } @article {4413, title = {The seasonal evolution of albedo across glaciers and the surrounding landscape of Taylor Valley, Antarctica}, journal = {The Cryosphere}, volume = {14}, year = {2020}, month = {03/2020}, pages = {769-788}, abstract = {

The McMurdo Dry Valleys (MDVs) of Antarctica are a polar desert ecosystem consisting of alpine glaciers, ice-covered lakes, streams, and expanses of vegetation-free rocky soil. Because average summer temperatures are close to 0\ oC, the MDV ecosystem in general, and glacier melt dynamics in particular, are both closely linked to the energy balance. A slight increase in incoming radiation or change in albedo can have large effects on the timing and volume of meltwater. However, the seasonal evolution or spatial variability of albedo in the valleys has yet to fully characterized. In this study, we aim to understand the drivers of landscape albedo change within and across seasons. To do so, a box with a camera, GPS, and shortwave radiometer was hung from a helicopter that flew transects four to five times a season along Taylor Valley. Measurements were repeated over three seasons. These data were coupled with incoming radiation measured at six meteorological stations distributed along the valley to calculate the distribution of albedo across individual glaciers, lakes, and soil surfaces. We hypothesized that albedo would decrease throughout the austral summer with ablation of snow patches and increasing sediment exposure on the glacier and lake surfaces. However, small snow events (\<6\ mm water equivalent) coupled with ice whitening caused spatial and temporal variability of albedo across the entire landscape. Glaciers frequently followed a pattern of increasing albedo with increasing elevation, as well as increasing albedo moving from east to west laterally across the ablation zone. We suggest that spatial patterns of albedo are a function of landscape morphology trapping snow and sediment, longitudinal gradients in snowfall magnitude, and wind-driven snow redistribution from east to west along the valley. We also compare our albedo measurements to the MODIS albedo product and found that overall the data have reasonable agreement. The mismatch in spatial scale between these two datasets results in variability, which is reduced after a snow event due to albedo following valley-scale gradients of snowfall magnitude. These findings highlight the importance of understanding the spatial and temporal variability in albedo and the close coupling of climate and landscape response. This new understanding of landscape albedo can constrain landscape energy budgets, better predict meltwater generation on from MDV glaciers, and how these ecosystems will respond to changing climate at the landscape scale.

}, keywords = {LTER-MCM}, doi = {10.5194/tc-14-769-2020}, url = {https://www.the-cryosphere.net/14/769/2020/}, author = {Bergstrom, Anna J. and Michael N. Gooseff and Myers, Madeline and Peter T. Doran and Cross, Julian M.} } @article {4403, title = {Subglacial brine flow and wind-induced internal waves in Lake Bonney, Antarctica}, journal = {Antarctic Science}, year = {2020}, month = {02/2020}, abstract = {

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

}, keywords = {LTER-MCM, Dry valleys, hypersalinity, lakes, proglacial, temperature}, doi = {10.1017/S0954102020000036}, url = {https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102020000036}, author = {Lawrence, Jade and Peter T. Doran and Winslow, Luke A. and John C. Priscu} } @article {4151, title = {Prediction of ice-free conditions for a perennially ice-covered Antarctic lake}, journal = {Journal of Geophysical Research: Earth Surface}, volume = {124}, year = {2019}, month = {02/2019}, abstract = {

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

}, keywords = {LTER-MCM}, doi = {10.1029/2018JF004756}, url = {https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018JF004756}, author = {Maciek K. Obryk and Peter T. Doran and John C. Priscu} } @mastersthesis {4365, title = {Spatiotemporal impact of snow on underwater photosynthetically active radiation in Taylor Valley, East Antarctica}, volume = {M.S.}, year = {2019}, month = {08/2019}, school = {Louisiana State University}, type = {masters}, address = {Baton Rouge, LA}, abstract = {

The role of snow on underwater photosynthetically active radiation (UW PAR) in the McMurdo Dry Valleys (MDVs) has been understudied due to lack of a detailed snowfall record. Research has shown that a relationship between snow cover and UW PAR exists, but the extent has never been evaluated in great detail. Although annual snowfall values in the MDVs are low (3 to 50 mm water equivalent annually), trends of increasing snowfall on the continent under future warming conditions could lead to an increased role for snow in regulating UW PAR (and associated primary productivity). Here, I discuss evidence from the snowfall record, surface PAR, and UW PAR, of the influence of snowfall on UW PAR in the major lakes of Taylor Valley. This study aims to quantify the spatiotemporal impact of lake ice snow packs on UW PAR in Taylor Valley from field surveys, long-term UW PAR, and meteorological data. Lake Fryxell has the strongest seasonality to precipitation, which decreases inland. On average, Lake Fryxell also has the most days with snow cover on the lake ice. Lake Hoare is experiencing an increase in Fall snow persistence since the 2007 snow year. Snow less than 0.5 mm snow water equivalent (SWE) can suppress UW PAR by 40\%. The calendar day that snow falls often determines whether phototrophs will switch from photosynthesis to respiration, which suggests the importance to seasonality in determining the impact of snow on photoautotrophs and lake-wide carbon budget.

}, keywords = {LTER-MCM}, url = {https://digitalcommons.lsu.edu/gradschool_theses/4965}, author = {Myers, Madeline and Peter T. Doran} } @article {4079, title = {Drivers of solar radiation variability in the McMurdo Dry Valleys, Antarctica}, journal = {Scientific Reports}, volume = {8}, year = {2018}, month = {03/2018}, abstract = {

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

}, keywords = {LTER-MCM}, doi = {10.1038/s41598-018-23390-7}, url = {http://www.nature.com/articles/s41598-018-23390-7.pdf}, author = {Maciek K. Obryk and Andrew G Fountain and Peter T. Doran and W. Berry Lyons and Eastman, R.} } @mastersthesis {4364, title = {Groundwater and thermal legacy of a large paleolake in Taylor Valley, East Antarctica as evidenced by airborne electromagnetic and sedimentological techniques}, volume = {M.S.}, year = {2018}, month = {07/2018}, school = {Louisiana State University}, type = {masters}, address = {Baton Rouge, LA}, abstract = {

During the Last Glacial Maximum, grounded ice in the Ross Sea extended into the otherwise ice-free McMurdo Dry Valleys, creating a series of large ice dammed paleolakes. Grounded ice within the mouth of Taylor Valley allowed for lake levels to reach elevations not possible at modern day and formed what is known as Glacial Lake Washburn (GLW). GLW extended from the eastern portion of Taylor Valley roughly 20 km west to a level ~300 m higher than modern day Lake Fryxell. The formation and existence of GLW has been debated, though previous studies correlate the timing of GLW with early Holocene grounded ice. Evidence of GLW has largely been constrained to the interpretation of glacial deposits and fluvial features such as lacustrine deposits, strandlines, and preserved paleodeltas. GIS and remote sensing techniques paired with regional resistivity data provide new insight into the paleohydrology of the region.

To quantify the extent of GLW, paleodelta locations were mapped using high resolution LiDAR digital elevation models and satellite imagery. Delta topset elevations were correlated between three streams in Fryxell basin to determine paleolake levels. Additionally, mean resistivity maps generated from airborne electromagnetic survey data (SkyTEM) reveal an extensive groundwater system within Fryxell basin which is interpreted as a legacy groundwater signal from GLW. Resistivity data suggests that active permafrost formation has been ongoing since onset of lake drainage, and that lake levels were over 60 m higher than modern only 1,000 \– 2,000 yr BP. This coincides with a warmer than modern paleoclimate inferred by ice core records, indicating a dynamic hydrological system that is highly sensitive to small changes in climate. As global temperatures increase, Lake Fryxell will continue to experience highly variable lake levels. Lakes and groundwater within the McMurdo Dry Valleys are critical to understanding impacts on the broader ecosystem which is largely driven by the availability of liquid water.

}, keywords = {LTER-MCM}, url = {https://digitalcommons.lsu.edu/gradschool_theses/4776}, author = {Myers, Krista F. and Peter T. Doran} } @article {4061, title = {The physical limnology of a permanently ice-covered and chemically stratified Antarctic lake using high resolution spatial data from an autonomous underwater vehicle}, journal = {Limnology and Oceanography}, volume = {63}, year = {2018}, month = {05/2018}, pages = {1234 - 1252}, abstract = {

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

}, keywords = {LTER-MCM}, doi = {10.1002/lno.10768}, url = {http://onlinelibrary.wiley.com/wol1/doi/10.1002/lno.10768/full}, author = {Spigel, Robert H. and John C. Priscu and Maciek K. Obryk and Stone, William C. and Peter T. Doran} } @article {4022, title = {Decadal ecosystem response to an anomalous melt season in a polar desert in Antarctica}, journal = {Nature Ecology \& Evolution}, volume = {1}, year = {2017}, month = {09/2017}, pages = {1334-1338}, keywords = {LTER-MCM}, doi = {10.1038/s41559-017-0253-0}, url = {https://www.nature.com/articles/s41559-017-0253-0}, author = {Michael N. Gooseff and John E. Barrett and Byron Adams and Peter T. Doran and Andrew G Fountain and W. Berry Lyons and Diane M. McKnight and John C. Priscu and Eric R. Sokol and Cristina D. Takacs-Vesbach and Martijn L. Vandegehuchte and Ross A. Virginia and Diana H. Wall} } @mastersthesis {4089, title = {Evidence of subglacial brine inflow and wind-induced mixing from high resolution temperature measurements in Lake Bonney, Antarctica}, volume = {M.S.}, year = {2017}, school = {Louisiana State University}, type = {masters}, address = {Baton Rouge, LA}, abstract = {

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

}, keywords = {LTER-MCM}, url = {https://digitalcommons.lsu.edu/gradschool_theses/4343}, author = {Lawrence, Jade and Peter T. Doran} } @article {4029, title = {The influence of f{\"o}hn winds on Glacial Lake Washburn and palaeotemperatures in the McMurdo Dry Valleys, Antarctica, during the Last Glacial Maximum}, journal = {Antarctic Science}, volume = {29}, year = {2017}, month = {10/2017}, pages = {457-467}, keywords = {LTER-MCM}, doi = {10.1017/S0954102017000062}, url = {https://www.cambridge.org/core/product/identifier/S0954102017000062/type/journal_article}, author = {Maciek K. Obryk and Peter T. Doran and Waddington, E.D. and Christopher P. McKay} } @article {3708, title = {Growth dynamics of a laminated microbial mat in response to variable irradiance in an Antarctic lake}, journal = {Freshwater Biology}, volume = {61}, year = {2016}, month = {02/2016}, pages = {396 - 410}, abstract = {
  1. Laminated microbial mats are important ecosystem components of perennially ice-covered Antarctic dry valley lakes. In order to understand better their response to changing environment, we made observations and carried out a manipulation experiment to determine their response to variations in irradiance in Lake Hoare (77\°38\′ S, 162\°53\′ E).
  2. Ice transparency was the most variable parameter that affected benthic light dose, both spatially and between years. Patterns of lamina accrual corresponded to irradiance history, with laminae that were initiated in high transmission years thicker than those from low transmission years.
  3. A shading experiment confirmed that accrual of lamina thickness, calcite precipitation and ash-free dry mass were determined by irradiance, but photosynthetic biomass and phototrophic species composition were less affected.
  4. Buried laminae decomposed only slowly over time, with potentially viable phototrophs many laminae down into the microbial mat. Decay rate increased only slightly with shading.
  5. We conclude that the microbial mats in Lake Hoare are characterised by remarkable stability, with slow accumulation rates and turnover of biomass over time. Photosynthetic biomass and species composition appeared to be stable across long time periods, with interannual variation in lamination pattern due to differential accumulation of extracellular polysaccharide and representing the visible expression of annual growth conditions.
}, keywords = {LTER-MCM}, doi = {10.1111/fwb.2016.61.issue-410.1111/fwb.12715}, url = {http://doi.wiley.com/10.1111/fwb.12715}, author = {Ian Hawes and Jungblut, Anne D. and Maciek K. Obryk and Peter T. Doran} } @article {3707, title = {High-resolution ground-penetrating radar profiles of perennial lake ice in the McMurdo Dry Valleys, Antarctica: Horizon attributes, unconformities, and subbottom penetration}, journal = {GEOPHYSICS}, volume = {81}, year = {2016}, month = {01/2016}, pages = {WA13 - WA20}, keywords = {LTER-MCM}, issn = {0016-8033}, doi = {10.1190/geo2015-0159.1}, url = {http://library.seg.org/doi/10.1190/geo2015-0159.1}, author = {Hilary A. Dugan and Arcone, Steven A. and Maciek K. Obryk and Peter T. Doran} } @article {4102, title = {The Impact of a Large-Scale Climate Event on Antarctic Ecosystem Processes}, journal = {BioScience}, volume = {66}, year = {2016}, month = {10/2016}, pages = {848 - 863}, abstract = {

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

}, keywords = {LTER-MCM}, issn = {0006-3568}, doi = {10.1093/biosci/biw110}, url = {http://academic.oup.com/bioscience/article-pdf/66/10/848/7510601/biw110.pdf}, author = {Andrew G Fountain and Saba, Grace and Byron Adams and Peter T. Doran and Fraser, William and Michael N. Gooseff and Maciek K. Obryk and John C. Priscu and Sharon E. Stammerjohn and Ross A. Virginia} } @article {3710, title = {Microbial Mat Communities along an Oxygen Gradient in a Perennially Ice-Covered Antarctic Lake}, journal = {Applied and Environmental Microbiology}, volume = {82}, year = {2016}, month = {01/2016}, pages = {620 - 630}, keywords = {LTER-MCM}, issn = {0099-2240}, doi = {10.1128/AEM.02699-15}, url = {http://aem.asm.org/lookup/doi/10.1128/AEM.02699-15}, author = {Jungblut, Anne D. and Ian Hawes and Mackey, Tyler J. and Krusor, Megan and Peter T. Doran and Sumner, Dawn Y. and Eisen, Jonathan A. and Hillman, Colin and Goroncy, Alexander K.}, editor = {Stams, A. J.} } @article {3919, title = {Modeling the thickness of perennial ice covers on stratified lakes of the Taylor Valley, Antarctica}, journal = {Journal of Glaciology}, year = {2016}, month = {06/2016}, pages = {1 - 10}, chapter = {1}, abstract = {
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.

}, keywords = {LTER-MCM}, issn = {0022-1430}, doi = {10.1017/jog.2016.69}, url = {http://www.journals.cambridge.org/abstract_S0022143016000691}, author = {Maciek K. Obryk and Peter T. Doran and J. A. Hicks and Christopher P. McKay and John C. Priscu} } @mastersthesis {4096, title = {Noble Gas Radioisotope Constraints on Water Residence Time and Solvent Sources in Lake Bonney}, volume = {M.S.}, year = {2016}, school = {University of Illinois}, type = {masters}, address = {Chicago, IL}, abstract = {

A noble gas radionuclide analysis of perennially ice covered West Lake Bonney was performed in order to determine water residence time and ice cover timing. Bulk gas samples were collected at four depths in the lake. Krypton and argon gases were selectively isolated from the bulk gas and measurements of 81Kr, 85Kr and 39Ar were made. Radiokrypton and radioargon analyses yielded lower limit ages of 78 to 285 years, significantly younger than expected based on previous dating efforts. It was determined that these new data do not invalidate previous work, but instead offer new insight into the timing of the most recent episode of direct communication between the atmosphere and West Lake Bonney waters.

}, keywords = {LTER-MCM, Antarctica, noble gas, radioargon, radiokrypton, residence time}, url = {http://hdl.handle.net/10027/21570}, author = {Cronin, Kyle D. and Peter T. Doran} } @article {4030, title = {Responses of Antarctic Marine and Freshwater Ecosystems to Changing Ice Conditions}, journal = {BioScience}, volume = {66}, year = {2016}, month = {Jan-10-2016}, pages = {864 - 879}, keywords = {LTER-MCM}, issn = {0006-3568}, doi = {10.1093/biosci/biw109}, url = {https://academic.oup.com/bioscience/article-lookup/doi/10.1093/biosci/biw109https://academic.oup.com/bioscience/article/66/10/864/2415532/Responses-of-Antarctic-Marine-and-Freshwater}, author = {Maciek K. Obryk and Peter T. Doran and Friedlaender, Ari S. and Michael N. Gooseff and Li, Wei and Rachael M. Morgan-Kiss and John C. Priscu and Schofield, Oscar and Sharon E. Stammerjohn and Steinberg, Deborah K. and Hugh W. Ducklow} } @article {3248, title = {Antarctic microbial mats: A modern analog for Archean lacustrine oxygen oases}, journal = {Geology}, year = {2015}, month = {10/2015}, pages = {G36966.1}, abstract = {

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

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

}, keywords = {LTER-MCM}, issn = {0091-7613}, doi = {10.1130/G36966.1}, url = {http://geology.gsapubs.org/lookup/doi/10.1130/G36966.1}, author = {Sumner, Dawn Y. and Ian Hawes and Mackey, Tyler J. and Jungblut, Anne D. and Peter T. Doran} } @article {3012, title = {Deep groundwater and potential subsurface habitats beneath an Antarctic dry valley}, journal = {Nature Communications}, volume = {6}, year = {2015}, month = {Apr-04-2017}, pages = {6831}, abstract = {The occurrence of groundwater in Antarctica, particularly in the ice-free regions and along the coastal margins is poorly understood. Here we use an airborne transient electromagnetic (AEM) sensor to produce extensive imagery of resistivity beneath Taylor Valley. Regional-scale zones of low subsurface resistivity were detected that are inconsistent with the high resistivity of glacier ice or dry permafrost in this region. We interpret these results as an indication that liquid, with sufficiently high solute content, exists at temperatures well below freezing and considered within the range suitable for microbial life. These inferred brines are widespread within permafrost and extend below glaciers and lakes. One system emanates from below Taylor Glacier into Lake Bonney and a second system connects the ocean with the eastern 18 km of the valley. A connection between these two basins was not detected to the depth limitation of the AEM survey (~350 m).}, keywords = {LTER-MCM}, doi = {10.1038/ncomms7831}, url = {http://www.nature.com/doifinder/10.1038/ncomms7831}, author = {Jill A. Mikucki and Auken, E. and Tulaczyk, S and Ross A. Virginia and Schamper, C. and S{\o}rensen, K. I. and Peter T. Doran and Hilary A. Dugan and Foley, N.} } @article {3213, title = {Reconstructing the evolution of Lake Bonney, Antarctica using dissolved noble gases}, journal = {Applied Geochemistry}, volume = {58}, year = {2015}, month = {Jan-07-2015}, pages = {46 - 61}, abstract = {

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

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

}, keywords = {LTER-MCM}, issn = {08832927}, doi = {10.1016/j.apgeochem.2015.02.013}, url = {http://linkinghub.elsevier.com/retrieve/pii/S088329271500044Xhttp://api.elsevier.com/content/article/PII:S088329271500044X?httpAccept=text/xmlhttp://api.elsevier.com/content/article/PII:S088329271500044X?httpAccept=text/plain}, author = {Warrier, Rohit B. and Clara M. Castro and Chris M. Hall and Kenig, Fabien and Peter T. Doran} } @article {1063, title = {Sediment transport dynamics on an ice-covered lake: The {\textquotedblleft}floating{\textquotedblright} boulders of Lake Hoare, Antarctica}, journal = {Antartic Science}, volume = {firstview}, year = {2015}, month = {04/2015}, pages = {1-12}, chapter = {1}, abstract = {

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

}, keywords = {LTER-MCM}, issn = {1365-2079}, doi = {10.1017/S0954102014000558}, url = {http://dx.doi.org/10.1017/S0954102014000558}, author = {P. P. Allen and R. Hewitt and Maciek K. Obryk and Peter T. Doran} } @article {3214, title = {Autonomous Year-Round Sampling and Sensing to Explore the Physical and Biological Habitability of Permanently Ice-Covered Antarctic Lakes}, journal = {Marine Technology Society Journal}, volume = {48}, year = {2014}, month = {Jan-09-2014}, pages = {8 - 17}, abstract = {

The lakes of the McMurdo Dry Valleys, Antarctica, are some of the only systems on our planet that are perennially ice-covered and support year-round metabolism. As such, these ecosystems can provide important information on conditions and life in polar regions on Earth and on other icy worlds in our solar system. Working in these extreme environments of the Dry Valleys poses many challenges, particularly with respect to data collection during dark winter months when logistical constraints make fieldwork difficult. In this paper, we describe the motivation, design, and challenges for this recently deployed instrumentation in Lake Bonney, a lake that has been the subject of summer research efforts for more than 40 years. The instrumentation deployed includes autonomous water, phytoplankton, and sediment samplers as well as cable-mounted profiling platforms with dissolved gas and fluorometry sensors. Data obtained from these instruments will allow us, for the first time, to define the habitability of this environment during the polar night. We include lessons learned during deployment and recommendations for effective instrument operation in these extreme conditions.

}, keywords = {LTER-MCM}, issn = {00253324}, doi = {10.4031/MTSJ.48.5.6}, url = {http://openurl.ingenta.com/content/xref?genre=article\&issn=0025-3324\&volume=48\&issue=5\&spage=8http://www.ingentaconnect.com/content/mts/mtsj/2014/00000048/00000005/art00002}, author = {Winslow, Luke A. and Hilary A. Dugan and Heather N. Buelow and Cronin, Kyle D. and John C. Priscu and Cristina D. Takacs-Vesbach and Peter T. Doran} } @article {1059, title = {Estimating photosynthetic activity in microbial mats in an ice-covered Antarctic lake using automated oxygen microelectode profiling and variable chlorophyll fluorescence}, journal = {Limnology and Oceanography}, volume = {59}, year = {2014}, month = {08/2014}, pages = {674-688}, chapter = {674}, abstract = { An automated oxygen microprofiler measured a positive flux of oxygen from microbial mats in ice-covered Lake Hoare, Antarctica, from noon, at a photon flux of 20 {\textmu}mol m-2 s-1, through to midnight (< 2 {\textmu}mol photons m-2 s-1). Daily average oxygen flux was 200 {\textmu}mol m-2 h-1; and, whereas it was maximal at noon, when a 10 mm broad concentration peak was observed 5 mm below the mat surface, flux correlated only weakly with irradiance. In contrast, relative electron transfer rate, estimated from variable chlorophyll fluorescence, suggested a linear relationship between photosystem activity and irradiance. This contradiction arose because of the conjunction of photosynthetic production of oxygen deep into these transparent, gelatinous mats (diel oxygen change was observed to 17 mm depth) and oxygen diffusion rates too slow to allow equilibration of oxygen concentration profiles with instantaneous production and consumption of oxygen. To confirm this, we developed a mathematical simulation of oxygen dynamics that included diffusion, photosynthesis, and respiration. The simulation further indicated that (1) net oxygen evolution is light limited is and confined to the upper few millimeters of the mat, (2) below 5{\textendash}7 mm, respiration balanced photosynthesis, (3) below 17 mm, respiration and photosynthesis approached zero, even though organic carbon and dissolved oxygen were present, and (4) photosynthesis deep into the mat was dependent on high light transmission through the gelatinous matrix. These conclusions are consistent with current understanding of mat growth dynamics and point to approaches for long-term analysis of microbial mat productivity.}, keywords = {LTER-MCM}, doi = {10.4319/lo.2014.59.3.0674}, author = {Ian Hawes and H. Giles and Peter T. Doran} } @phdthesis {4097, title = {Geophysics, Water Balance, and History of Thick Perennial Ice Covers on Antarctic Lakes}, volume = {Ph.D.}, year = {2014}, school = {University of Illinois}, type = {doctoral}, address = {Chicago, IL}, abstract = {

Antarctic lakes are studied as sentinels of future change, for paleolimnological records contained in the sediments, and as habitats for the simple food webs that can exist in inhospitable environments. Understanding how lakes are formed and are sustained in response to landscape and climate conditions is critical in addressing the aforementioned research themes. This thesis is governed by the overarching hypothesis that an understanding of hydrologic and sediment transport processes associated with lake ice formation and preservation can be used to reveal past climatic changes, and further our awareness of current changes in climate and water balance in the McMurdo Dry Valleys of Antarctica. The first chapter focuses on water loss from closed basin lakes in Taylor Valley, Antarctica, and presents updated estimates of sublimation and ablation rates from long-term empirical measurements. The second and third chapters address the formation of Lake Vida, Antarctica. The former investigates the accretion of a 27 m ice cover, and considers the origin of thick sediment layers in the ice cover, and the latter uses two geophysical methods to quantify the extent and volume of the brine network in the subsurface beneath the lake. The results presented herein advance the study of hydrogeology in continuous permafrost, provide additional evidence for fluctuating climate states in the McMurdo Dry Valleys throughout the mid to late Holocene, and provide a case study for the preservation of water in a cold, desert environment analogous to neighboring planets.

}, keywords = {LTER-MCM, Antarctica, brine, lake ice, McMurdo Dry Valleys, polar lakes, sublimation}, url = {http://hdl.handle.net/10027/19407}, author = {Hilary A. Dugan}, editor = {Peter T. Doran} } @phdthesis {4091, title = {Hydrological and Biogeochemical Modeling of Taylor Valley Lakes, East Antarctica}, volume = {Ph.D.}, year = {2014}, school = {University of Illinois}, type = {doctoral}, address = {Chicago, IL}, abstract = {

Taylor Valley, McMurdo Dry Valleys, East Antarctica contains three perennially ice-covered lakes located in closed basins. The lakes respond to climatic changes on seasonal and decadal scales due to their existence on a very narrow climatic spectrum. The climate has to be sufficiently warm during the austral summer to induce glacial melt yet cold enough to maintain the ice covers year round. This thesis is focused on better understanding and constraining the sensitivity of past and present lakes to changes in climatic forcings. Melt water generation for large proglacial lakes, that existed during the Last Glacial Maximum, is attributed to strong westerly winds that increase surface air temperature above freezing, prolonging the melt season. The high frequency of westerly winds during the Last Glacial Maximum, based on the ice core record from Taylor Dome, is responsible for generation of enough glacial melt to sustain large proglacial lakes during this time period, suggesting that summer surface air temperatures were as warm as present day. Contemporary lakes are much smaller, however, the effect of strong westerly winds on modern lakes is equally profound. Strong winds are responsible for aeolian sediment deposition on the surface of the ice covers. The deposited sediment, on the other hand, absorbs more solar radiation and preferentially decreases the ice thickness around it. The localized ice thinning allows a greater amount of light penetration into the water column, which is negatively correlated with chlorophyll-a concentration. This negative correlation does not indicate changes in biomass; rather, it is a result of the short-term photo-adaptation of phytoplankton to the light intensity by increasing/decreasing light harvesting antenna size. The ice thicknesses in Taylor Valley lakes have been fluctuating since the first measurements were obtained. A one-dimensional physics-based ice thickness model was developed capable of reproducing 16 years of ice thickness trends for two different lakes. The model is based on surface radiative fluxes while considering heat fluxes from the water column. Deep lakes with well-developed temperature maximum can facilitate or hinder ice thickness growth/decay due to the heat flux from the underlying water column. This finding suggests that not all perennially ice-covered lakes can be used as a proxy for climatic changes.

}, keywords = {LTER-MCM}, url = {http://hdl.handle.net/10027/18909}, author = {Maciek K. Obryk}, editor = {Peter T. Doran} } @article {3212, title = {The permanent ice cover of Lake Bonney, Antarctica: The influence of thickness and sediment distribution on photosynthetically available radiation and chlorophyll-a distribution in the underlying water column}, journal = {Journal of Geophysical Research: Biogeosciences}, volume = {119}, year = {2014}, month = {09/2014}, pages = {1879 - 1891}, chapter = {1879}, abstract = {

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

}, keywords = {LTER-MCM}, doi = {10.1002/2014JG002672}, url = {http://doi.wiley.com/10.1002/2014JG002672}, author = {Maciek K. Obryk and Peter T. Doran and John C. Priscu} } @article {1062, title = {Radiocarbon abundance and reservoir effects in lakes of the McMurdo Dry Valleys, Antarctica}, journal = {Limnology and Oceanography}, volume = {59}, year = {2014}, month = {05/2014}, pages = {811-826}, chapter = {811}, keywords = {LTER-MCM}, author = {Peter T. Doran and Kenig, Fabien and Lawson Knoepfle and Jill A. Mikucki and W. Berry Lyons} } @article {3211, title = {Carbon Sequestration and Release from Antarctic Lakes: Lake Vida and West Lake Bonney (McMurdo Dry Valleys)}, journal = {Aquatic Geochemistry}, volume = {19}, year = {2013}, month = {03/2013}, pages = {135 - 145}, abstract = {

Perennial ice covers on many Antarctic lakes have resulted in high lake inorganic carbon contents. The objective of this paper was to evaluate and compare the brine and CO2\ chemistries of Lake Vida (Victoria Valley) and West Lake Bonney (Taylor Valley), two lakes of the McMurdo Dry Valleys (East Antarctica), and their potential consequences during global warming. An existing geochemical model (FREZCHEM-15) was used to convert measured molarity into molality needed for the FREZCHEM model, and this model added a new algorithm that converts measured DIC into carbonate alkalinity needed for the FREZCHEM model. While quite extensive geochemical information exists for ice-covered Taylor Valley lakes, such as West Lake Bonney, only limited information exists for the recently sampled brine of \>25\ m ice-thick Lake Vida. Lake Vida brine had a model-calculated pCO2\ =\ 0.60 bars at the field pH (6.20); West Lake Bonney had a model-calculated pCO2\ =\ 5.23\ bars at the field pH (5.46). Despite the high degree of atmospheric CO2supersaturation in West Lake Bonney, it remains significantly undersaturated with the gas hydrate, CO2\·6H2O, unless these gas hydrates are deep in the sediment layer or are metastable having formed under colder temperatures or greater pressures. Because of lower temperatures, Lake Vida could start forming CO2\·6H2O at lower pCO2\ values than West Lake Bonney; but both lakes are significantly undersaturated with the gas hydrate, CO2\·6H2O. For both lakes, simulation of global warming from current subzero temperatures (\−13.4\ \°C in Lake Vida and \−4.7\ \°C in West Lake Bonney) to 10\ \°C has shown that a major loss of solution-phase carbon as CO2\ gases and carbonate minerals occurred when the temperatures rose above 0\ \°C and perennial ice covers would disappear. How important these Antarctic CO2\ sources will be for future global warming remains to be seen. But a recent paper has shown that methane increased in atmospheric concentration due to deglaciation about 10,000\ years ago. So, CO2\ release from ice lakes might contribute to atmospheric gases in the future.

}, keywords = {LTER-MCM}, issn = {1380-6165}, doi = {10.1007/s10498-012-9184-1}, url = {http://link.springer.com/10.1007/s10498-012-9184-1http://link.springer.com/content/pdf/10.1007/s10498-012-9184-1}, author = {G. M. Marion and A. E. Murray and Wagner, Bernd and Christian H. Fritsen and Kenig, Fabien and Peter T. Doran} } @article {1076, title = {Distribution of Siliceous-Walled Algae in Taylor Valley, Antarctica Lakes}, journal = {International Journal of Geosciences}, volume = {04}, year = {2013}, month = {2013}, pages = {688 - 699}, keywords = {LTER-MCM}, doi = {10.4236/ijg.2013.44064}, author = {Jonathan P. Warnock and Peter T. Doran} } @article {1098, title = {Lake ice ablation rates from permanently ice-covered Antarctic lakes}, journal = {Journal of Glaciology}, volume = {59}, year = {2013}, month = {01/2013}, keywords = {LTER-MCM}, author = {Hilary A. Dugan and Maciek K. Obryk and Peter T. Doran} } @article {1080, title = {Micro-hole and multigrain quartz luminescence dating of Paleodeltas at Lake Fryxell, McMurdo Dry Valleys (Antarctica), and relevance for lake history}, journal = {Quaternary Geochronology}, volume = {18}, year = {2013}, month = {12/2013}, pages = {119 - 134}, keywords = {LTER-MCM}, doi = {10.1016/j.quageo.2013.04.002}, url = {http://www.sciencedirect.com/science/article/pii/S1871101413000423}, author = {G. W. Berger and Peter T. Doran and Thomsen, K.J.} } @article {1104, title = {The geochemistry of upland ponds, Taylor Valley, Antarctica}, journal = {Antarctic Science}, volume = {24}, year = {2012}, month = {2/2012}, pages = {3 - 14}, keywords = {LTER-MCM}, doi = {10.1017/S0954102011000617}, url = {http://journals.cambridge.org/action/displayAbstract?fromPage=online\&aid=8483351}, author = {W. Berry Lyons and Kathleen A. Welch and Christopher B. Gardner and Chris Jaros and Daryl L. Moorhead and Knoepfle, J and Peter T. Doran} } @article {3528, title = {Microbial life at -13 ~C in the brine of an ice-sealed Antarctic lake}, journal = {Proceedings of the National Academy of Sciences}, volume = {109}, year = {2012}, month = {12/2012}, pages = {20626 - 20631}, keywords = {LTER-MCM}, issn = {0027-8424}, doi = {10.1073/pnas.1208607109}, url = {http://www.pnas.org/cgi/doi/10.1073/pnas.1208607109}, author = {A. E. Murray and Kenig, Fabien and Christian H. Fritsen and Christopher P. McKay and Kaelin M. Cawley and R. L. Edwards and Kuhn, Emanuele and Diane M. McKnight and Nathaniel E Ostrom and Vivian Peng and Adrian Ponce and John C. Priscu and Samarkin, Vladimir A. and Ashley T Townsend and Protima Wagh and Seth A Young and Pung To Yung and Peter T. Doran} } @book {1123, title = {Poisson Reconstruction of Extreme Submersed Environments: The ENDURANCE Exploration of an Under-Ice Antarctic Lake}, series = {Advances in Visual Computing. ISVC 2012. Lecture Notes in Computer Science.}, volume = {7431}, year = {2012}, pages = {394 - 403}, publisher = {Springer Berlin Heidelberg}, organization = {Springer Berlin Heidelberg}, address = {Berlin, Heidelberg}, abstract = {

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

}, keywords = {LTER-MCM}, isbn = {978-3-642-33179-4}, doi = {10.1007/978-3-642-33179-4_38}, url = {http://www.springerlink.com/content/hg97w43588229087/}, author = {Alessandro Febretti and Kristof Richmond and Gulati, Shilpa and Flesher, Christopher and Hogan, Bartholomew P. and Andrew Johnson and Stone, William C. and John C. Priscu and Peter T. Doran}, editor = {Bebis, George and Boyle, Richard and Parvin, Bahram and Koracin, Darko and Fowlkes, Charless and Wang, Sen and Choi, Min-Hyung and Mantler, Stephan and Schulze, J{\"u}rgen and Acevedo, Daniel and Mueller, Klaus and Papka, Michael} } @article {1136, title = {A diatom record of environmental change in Fryxell Basin, Taylor Valley, Antarctica, late Pleistocene to present}, journal = {Journal of Paleolimnology}, volume = {46}, year = {2011}, month = {08/2011}, pages = {257 - 272}, keywords = {LTER-MCM}, doi = {10.1007/s10933-011-9537-6}, url = {http://www.springerlink.com/content/y3483576u8220081/}, author = {Matthew A. Konfirst and Charlotte Sjunneskog and Reed P. Scherer and Peter T. Doran} } @proceedings {1139, title = {Environmental Protection and Stewardship of Subglacial Aquatic Environments}, journal = {AGU Chapman Conference}, volume = {192}, year = {2011}, month = {03/2011}, pages = {149-157}, publisher = {American Geophysical Union, Washington, DC}, address = {Baltimore}, keywords = {LTER-MCM}, author = {Peter T. Doran and Warwick F. Vincent} } @article {1127, title = {The Holocene environmental history of Lake Hoare, Taylor Valley, Antarctica, reconstructed from sediment cores}, journal = {Antarctic Science}, volume = {23}, year = {2011}, month = {6/2011}, pages = {307 - 319}, keywords = {LTER-MCM}, doi = {10.1017/S0954102011000125}, url = {http://journals.cambridge.org/action/displayAbstract?fromPage=online\&aid=8275374}, author = {Wagner, Bernd and Ortlepp, Sabrina and Peter T. Doran and Kenig, Fabien and Melles, Martin and Andy Burkemper} } @article {1135, title = {Hydrological Connectivity of the Landscape of the McMurdo Dry Valleys, Antarctica}, journal = {Geography Compass}, volume = {5}, year = {2011}, month = {09/2011}, pages = {666 - 681}, keywords = {LTER-MCM}, doi = {10.1111/j.1749-8198.2011.00445.x}, url = {http://onlinelibrary.wiley.com/doi/10.1111/j.1749-8198.2011.00445.x}, author = {Michael N. Gooseff and Diane M. McKnight and Peter T. Doran and Andrew G Fountain and W. Berry Lyons} } @inbook {1168, title = {Antarctic McMurdo Dry Valley stream ecosystems as analog to fluvial systems on Mars}, booktitle = {Life in Antarctic Deserts and other Cold Dry Environments}, year = {2010}, pages = {139 - 159}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, address = {Cambridge}, keywords = {LTER-MCM}, isbn = {9780521889193}, doi = {10.1017/CBO9780511712258.005}, author = {Michael N. Gooseff and Diane M. McKnight and Carr, M. H. and Baeseman, J.}, editor = {Peter T. Doran and W. Berry Lyons and Diane M. McKnight} } @article {1157, title = {Design and deployment of a four-degrees-of-freedom hovering autonomous underwater vehicle for sub-ice exploration and mapping}, journal = {Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment}, volume = {224}, year = {2010}, month = {11/2010}, pages = {341 - 361}, keywords = {LTER-MCM}, doi = {10.1243/14750902JEME214}, author = {Stone, W and Bartholomew P Hogan and Flesher, C and Gulati, S and Kristof Richmond and Murarka, A and Kuhlman, G and Idharan, M and Siegel, V and Price, R M and Peter T. Doran and John C. Priscu} } @article {1165, title = {A dynamic physical model for soil temperature and water in Taylor Valley, Antarctica.}, journal = {Antarctic Science}, year = {2010}, month = {05/13/2010}, pages = {419-434}, type = {Journal}, keywords = {LTER-MCM}, doi = {10.1017/S0954102010000234}, author = {H. W. Hunt and Andrew G Fountain and Peter T. Doran and Hassan J. Basagic} } @book {1173, title = {Life in Antarctic Deserts and Other Cold Environments}, series = {Astrobiological Analogs}, volume = {5}, year = {2010}, pages = {307}, publisher = {Cambridge University Press.}, organization = {Cambridge University Press.}, address = {Cambridge}, keywords = {LTER-MCM, Planetary Science}, isbn = {9780511712258}, doi = {10.1017/CBO9780511712258}, url = {http://ebooks.cambridge.org/ebook.jsf?bid=CBO9780511712258}, author = {Peter T. Doran and W. Berry Lyons and Diane M. McKnight}, editor = {Diane M. McKnight and Michael N. Gooseff and Cristina D. Takacs-Vesbach and Jill A. Mikucki and Martyn Tranter and Sun, Henry J} } @article {1167, title = {New insights into the origin and evolution of Lake Vida, McMurdo Dry Valleys, Antarctica {\textemdash} A noble gas study in ice and brines}, journal = {Earth and Planetary Science Letters}, volume = {289}, year = {2010}, month = {01/2010}, pages = {112 - 122}, keywords = {LTER-MCM}, doi = {10.1016/j.epsl.2009.10.034}, url = {http://www.sciencedirect.com/science/article/pii/S0012821X09006335}, author = {Jessica L. Malone and Clara M. Castro and Chris M. Hall and Peter T. Doran and Kenig, Fabien and Christopher P. McKay} } @article {1149, title = {Origin and tentative identification of tri to pentaunsaturated ketones in sediments from Lake Fryxell, East Antarctica}, journal = {Organic Geochemistry}, volume = {41}, year = {2010}, month = {4/2010}, pages = {386 - 397}, keywords = {LTER-MCM}, doi = {10.1016/j.orggeochem.2009.12.004}, author = {Jaraula, Caroline M.B. and Brassell, Simon C. and Rachael M. Morgan-Kiss and Peter T. Doran and Kenig, Fabien} } @article {1158, title = {Palaeoenvironmental implications derived from a piston core from east lobe Bonney, Taylor Valley, Antarctica}, journal = {Antarctic Science}, volume = {22}, year = {2010}, month = {10/2010}, pages = {522 - 530}, keywords = {LTER-MCM}, doi = {10.1017/S0954102010000556}, author = {Wagner, Bernd and Ortlepp, Sabrina and Kenig, Fabien and Peter T. Doran and Melles, Martin} } @inbook {1175, title = {Saline lakes and ponds in the McMurdo Dry Valleys: ecological analogs to martian paleolake environments}, booktitle = {Life in Antarctic Deserts and other Cold Dry Environments}, year = {2010}, pages = {160 - 194}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, address = {Cambridge}, keywords = {LTER-MCM}, isbn = {9780521889193}, doi = {10.1017/CBO9780511712258.006}, url = {http://ebooks.cambridge.org/chapter.jsf?bid=CBO9780511712258\&cid=CBO9780511712258A013}, author = {Jill A. Mikucki and W. Berry Lyons and Ian Hawes and Brian D. Lanoil and Peter T. Doran} } @article {1153, title = {Single-grain and multigrain luminescence dating of on-ice and lake-bottom deposits at Lake Hoare, Taylor Valley, Antarctica}, journal = {Quaternary Geochronology}, volume = {5}, year = {2010}, month = {12/2010}, pages = {679 - 690}, keywords = {LTER-MCM}, doi = {10.1016/j.quageo.2010.05.003}, author = {G. W. Berger and Peter T. Doran and Thomsen, K.J.} } @conference {1164, title = {Toward autonomous scientific exploration of ice-covered lakes{\textemdash}Field experiments with the ENDURANCE AUV in an Antarctic Dry Valley}, booktitle = {2010 IEEE International Conference on Robotics and Automation (ICRA 2010)2010 IEEE International Conference on Robotics and Automation}, year = {2010}, month = {05/2010}, pages = {308 - 315}, publisher = {IEEE}, organization = {IEEE}, address = {Anchorage, AK}, keywords = {LTER-MCM}, isbn = {978-1-4244-5038-1}, doi = {10.1109/ROBOT.2010.5509224}, author = {Gulati, S and Kristof Richmond and Flesher, C and Bartholomew P Hogan and Murarka, A and Gregory Kuhlmann and Mohan Sridharan and Stone, W and Peter T. Doran} } @article {1185, title = {Composition and Biodegradation of a Synthetic Oil Spilled on the Perennial Ice Cover of Lake Fryxell, Antarctica}, journal = {Environmental Science \& Technology}, volume = {43}, year = {2009}, pages = {2708-2713}, keywords = {LTER-MCM}, doi = {LTER}, author = {Jaraula, C and Kenig, Fabien and Peter T. Doran and John C. Priscu and Kathleen A. Welch} } @article {1178, title = {Examining the Scientific Consensus on Climate Change}, journal = {Eos, Transactions American Geophysical Union}, volume = {90}, year = {2009}, month = {2009}, pages = {22}, keywords = {LTER-MCM}, doi = {10.1029/2009EO030002}, url = {http://www.agu.org/pubs/crossref/2009/2009EO030002.shtm}, author = {Peter T. Doran and Maggie K. Zimmerman} } @article {1191, title = {Particulate organic and dissolved inorganic carbon stable isotopic compositions in Taylor Valley lakes, Antarctica: the effect of legacy}, journal = {Hydrobiologia}, volume = {632}, year = {2009}, pages = {139-156}, keywords = {LTER-MCM}, doi = {LTER}, author = {Knoepfle, J and Peter T. Doran and Kenig, Fabien and W. Berry Lyons and Galchenko, V} } @article {1179, title = {Reply to Comments on {\textquotedblleft}Examining the Scientific Consensus on Climate Change{\textquotedblright}}, journal = {Eos, Transactions American Geophysical Union}, volume = {90}, year = {2009}, month = {2009}, pages = {233}, keywords = {LTER-MCM}, doi = {10.1029/2009EO270010}, author = {Peter T. Doran and Maggie K. Zimmerman} } @article {1212, title = {Entry approach into pristine ice-sealed lakes - Lake Vida, East Antarctica, a model ecosystem}, journal = {Limnology and Oceanography-Methods}, volume = {6}, year = {2008}, pages = {542-547}, keywords = {LTER-MCM}, doi = {LTER}, author = {Peter T. Doran and Christian H. Fritsen and A. E. Murray and Kenig, Fabien and Christopher P. McKay and Kyne, J} } @article {1204, title = {Hydrologic response to extreme warm and cold summers in the McMurdo Dry Valleys, East Antarctica}, journal = {Antarctic Science}, volume = {20}, year = {2008}, month = {05/16/2008}, pages = {499-509}, type = {Journal}, keywords = {LTER-MCM, Climate Response, streams}, doi = {10.1017/S0954102008001272}, author = {Peter T. Doran and Christopher P. McKay and Andrew G Fountain and Thomas H. Nylen and Diane M. McKnight and Chris Jaros and John E. Barrett} } @inbook {1220, title = {Origin and geomorphology of lakes in the polar regions}, booktitle = {Polar Lakes and Rivers: Limnology of Arctic and Antarctic Aquatic Ecosystems}, year = {2008}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {Oxford}, keywords = {LTER-MCM}, doi = {LTER}, author = {Pienitz, R and Peter T. Doran and Lamoureuz, S}, editor = {Warwick F. Vincent and Johanna Laybourn-Parry} } @mastersthesis {1222, title = {Provenance of organic matter in Taylor Valley, Antarctica lakes: Scanning Electron Microscopy of sediment}, volume = {M.S.}, year = {2008}, school = {University of Illinois, Chicago}, type = {masters}, keywords = {LTER-MCM}, doi = {LTER}, author = {Jonathan P. Warnock} } @article {1201, title = {Reply to comment by K. Gajewski on {\textquotedblleft}Abrupt environmental change in Canada{\textquoteright}s northernmost lake{\textquotedblright}}, journal = {Geophysical Research Letters}, volume = {35}, year = {2008}, month = {2008}, keywords = {LTER-MCM}, doi = {10.1029/2007GL032889}, url = {http://www.agu.org/pubs/crossref/2008/2007GL032889.shtml}, author = {Dermot Antoniades and Catherine Crawley and Douglas, Marianne S. V. and Pienitz, R and Dale T. Andersen and Peter T. Doran and Ian Hawes and Pollard, W and Warwick F. Vincent} } @article {1223, title = {SPME-GCMS study of the natural attenuation of aviation diesel spilled on the perennial ice cover of Lake Fryxell, Antarctica}, journal = {Science of the Total Environment}, volume = {407}, year = {2008}, pages = {250-262}, keywords = {LTER-MCM}, author = {Jaraula, C and Kenig, Fabien and Peter T. Doran and John C. Priscu and Kathleen A. Welch} } @article {1236, title = {Biogeochemical stoichiometry of Antarctic Dry Valley ecosystems}, journal = {Journal of Geophysical Research}, volume = {112}, year = {2007}, month = {02/2007}, pages = {G01010+12}, abstract = {

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

}, keywords = {LTER-MCM, Biggie}, doi = {10.1029/2005JG000141}, author = {John E. Barrett and Ross A. Virginia and W. Berry Lyons and Diane M. McKnight and John C. Priscu and Andrew G Fountain and Diana H. Wall and Daryl L. Moorhead and Peter T. Doran} } @mastersthesis {1243, title = {Lacustrine History of Lake Hoare, McMurdo Dry Valleys, Antarctica, Based on Long Sediment Cores}, volume = {M.S.}, year = {2007}, school = {University of Illinois, Chicago}, type = {masters}, keywords = {LTER-MCM}, doi = {LTER}, author = {Andy Burkemper} } @mastersthesis {1250, title = {Stable Carbon Isotope Analyses of Sediments from Lake Fryxell, Antarctica}, volume = {M.S.}, year = {2007}, school = {University of Illinois, Chicago}, type = {masters}, keywords = {LTER-MCM}, doi = {LTER}, author = {Moore-Topinka, N} } @proceedings {1251, title = {Trends in discharge and flow season timing of the Onyx River, Wright Valley, Antarctica since 1969}, journal = {Antarctica; A keystone in a changing world--online proceedings for the tenth international symposium}, year = {2007}, publisher = {U.S. Geological Survey Open-File Report 2007-1047}, keywords = {LTER-MCM}, doi = {LTER}, author = {Michael N. Gooseff and Diane M. McKnight and Peter T. Doran and W. Berry Lyons}, editor = {Alan Cooper and Carol Raymond and ISAES Editorial Team} } @article {1256, title = {Antarctic Climate Cooling and Response of Diatoms in Glacial Meltwater Streams}, journal = {Geophysical Research Letters}, volume = {33}, year = {2006}, month = {04/2006}, pages = {L07406}, type = {Journal}, abstract = {

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

}, keywords = {LTER-MCM, Biggie}, doi = {10.1029/2006GL025903}, author = {Rhea M.M. Esposito and Horn, S and Diane M. McKnight and Cox, M and Grant, M and Sarah A. Spaulding and Peter T. Doran and Cozzetto, K} } @article {1269, title = {Glacial and postglacial sedimentation in the Fryxell basin, Taylor Valley, Southern Victoria Land, Antarctica}, journal = {Palaeography, Palaeoclimatology, Palaeoecology}, volume = {341}, year = {2006}, pages = {320}, keywords = {LTER-MCM}, doi = {LTER}, author = {Wagner, B and Melles, M and Peter T. Doran and Kenig, Fabien and Forman, S and Pierau, R and Allan, P} } @article {1291, title = {Biogeological Raman spectroscopic studies of Antarctic lacustrine sediments}, journal = {Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy}, volume = {61}, year = {2005}, keywords = {LTER-MCM}, author = {Moody, C and Villar, S and Edwards, H and Hodgson, D and Peter T. Doran and J.L. Bishop} } @article {1293, title = {Comment on {\textquoteleft}{\textquoteleft}El Ni{\~n}o suppresses Antarctic warming{\textquoteright}{\textquoteright} by N. Bertler et al.}, journal = {Geophysical Research Letters}, volume = {32}, year = {2005}, pages = {L07706}, keywords = {LTER-MCM, Tropical meteorology}, doi = {10.1029/2004GL021716}, author = {Peter T. Doran and Gary D. Clow and Christian H. Fritsen and Christopher P. McKay and Andrew N. Parsons and John C. Priscu and W. Berry Lyons and Walsh, J and Andrew G Fountain and Diane M. McKnight and Daryl L. Moorhead and Ross A. Virginia and Diana H. Wall} } @article {1294, title = {Dating water and solute additions to ice-covered Antarctic lakes}, journal = {Geochimica et Cosmochimica Acta}, volume = {69}, year = {2005}, pages = {A720}, keywords = {LTER-MCM}, author = {W. Berry Lyons and Carolyn Dowling and Kathleen A. Welch and Snyder, G and Robert J. Poreda and Peter T. Doran and Andrew G Fountain} } @article {1299, title = {Groundwater seeps in Taylor Valley Antarctica: An example of a subsurface melt event}, journal = {Annals of Glaciology}, volume = {40}, year = {2005}, pages = {200-206}, keywords = {LTER-MCM}, doi = {LTER}, author = {W. Berry Lyons and Kathleen A. Welch and Anne E. Carey and Diana H. Wall and Ross A. Virginia and Andrew G Fountain and Peter T. Doran and Csatho, B and Tremper, C} } @phdthesis {1301, title = {Lacustrine Biogeochemistry of the McMurdo Dry Valleys}, volume = {Ph.D.}, year = {2005}, school = {University of Illinois, Chicago}, type = {doctoral}, keywords = {LTER-MCM}, doi = {LTER}, author = {Lawson, J} } @inbook {1306, title = {Polar lakes, streams, and springs as analogs for the hydrological cycle on Mars.}, booktitle = {Advances in Astrobiology and Biogeophysics}, year = {2005}, pages = {219-233}, publisher = {Springer Verlag}, organization = {Springer Verlag}, address = {Berlin, Heidelberg}, keywords = {LTER-MCM}, doi = {LTER}, url = {/reports/lakes/McKayEtAl2005StreamsSprings.pdf}, author = {Christopher P. McKay and Dale T. Andersen and Pollard, W and Heldmann, J and Peter T. Doran and Christian H. Fritsen and John C. Priscu} } @inbook {1322, title = {Antarctic Paleolimnology}, booktitle = {Long-Term Environmental Change in Arctic and Antarctic Lakes}, year = {2004}, publisher = {Kluwer Academic Publishers}, organization = {Kluwer Academic Publishers}, keywords = {LTER-MCM}, author = {Hodgson, D and John A. E. Gibson and Peter T. Doran}, editor = {Pienitz, R and Douglas, Marianne S. V. and J.P. Smol} } @article {1326, title = {Climatology of Katabatic Winds in the McMurdo Dry Valleys, Southern Victoria Land, Antarctica}, journal = {Journal of Geophysical Research}, volume = {109}, year = {2004}, keywords = {LTER-MCM}, author = {Thomas H. Nylen and Andrew G Fountain and Peter T. Doran} } @inbook {1332, title = {Geochronology of high latitude lake sediments}, booktitle = {Long-Term Environmental Change in Arctic and Antarctic Lakes}, year = {2004}, publisher = {Kluwer Academic Publishers}, organization = {Kluwer Academic Publishers}, keywords = {LTER-MCM}, author = {Wolf, A and Miller, G and Olsen, C and Forman, S and Peter T. Doran and Holmgren, S}, editor = {Pienitz, R and Douglas, Marianne S. V. and J.P. Smol} } @inbook {1339, title = {Paleolimnology of extreme cold terrestrial and extraterrestrial environments.}, booktitle = {Long-Term Environmental Change in Arctic and Antarctic Lakes}, year = {2004}, pages = {475-507}, publisher = {Kluwer Academic Publishers}, organization = {Kluwer Academic Publishers}, address = {Dordrecht, The Netherlands}, keywords = {LTER-MCM}, isbn = {978-1-4020-2125-1}, author = {Peter T. Doran and John C. Priscu and W. Berry Lyons and Powell, R and Robert J. Poreda and Dale T. Andersen} } @inbook {1340, title = {Paleolimnology of Ice-covered Environments}, booktitle = {Long-term environmental change in Arctic and Antarctic lakes}, year = {2004}, pages = {475-507}, publisher = {Kluwer Academic Publishers}, organization = {Kluwer Academic Publishers}, keywords = {LTER-MCM}, author = {Peter T. Doran and John C. Priscu and W. Berry Lyons and Powell, R and Robert J. Poreda}, editor = {Pienitz, R and Douglas, Marianne S. V. and John Smol} } @article {1343, title = {Stable carbon and nitrogen isotopic compositions of benthic and pelagic organic matter in four polar lakes of the McMurdo Dry Valleys, Antarctica}, journal = {Aquatic Geochemistry}, volume = {10}, year = {2004}, pages = {269-301}, keywords = {LTER-MCM}, author = {Lawson, J and Peter T. Doran and Kenig, Fabien and David J. DesMarais and John C. Priscu} } @mastersthesis {1362, title = {Distribution of 210Pb and 137Cs in the McMurdo Dry Valleys, Antarctica}, volume = {M.S.}, year = {2003}, school = {University of Illinois, Chicago}, type = {masters}, keywords = {LTER-MCM}, doi = {LTER}, author = {Olsen, C} } @article {1357, title = {Formation and character of an ancient 19 m ice cover and underlying trapped brine in an}, journal = {Proceedings of National Academy of Sciences}, volume = {100}, year = {2003}, month = {01/2003}, pages = {26-31}, type = {Journal}, keywords = {LTER-MCM}, doi = {10.1073/pnas.222680999}, url = {http://www.pnas.org/content/100/1/26.short}, author = {Peter T. Doran and Christian H. Fritsen and Christopher P. McKay and John C. Priscu and Edward E. Adams} } @article {1363, title = {Fourier-transform raman spectroscopic studies of organic and inorganic chemical components in stromatolitic cores from Antarctic lake sediments}, journal = {International Journal of Astrobiology}, volume = {1}, year = {2003}, pages = {325-331}, keywords = {LTER-MCM}, author = {Edwards, H and Wynn-Williams, D and Ellis-Evans, J and Newton, E and Little, S and de Oliveira, L and Hodgson, D and Peter T. Doran} } @article {1377, title = {Antarctic climate cooling and terrestrial ecosystem response}, journal = {Nature}, volume = {415}, year = {2002}, month = {01/2002}, pages = {517-520}, type = {Journal}, keywords = {LTER-MCM, Climate Response}, doi = {10.1038/nature710}, author = {Peter T. Doran and John C. Priscu and W. Berry Lyons and John E. Walsh and Andrew G Fountain and Diane M. McKnight and Daryl L. Moorhead and Ross A. Virginia and Diana H. Wall and Gary D. Clow and Christian H. Fritsen and Christopher P. McKay and Andrew N. Parsons} } @article {1382, title = {Recent Temperature Trends in the Antarctic}, journal = {Nature}, volume = {418}, year = {2002}, pages = {291-292}, keywords = {LTER-MCM}, author = {John E. Walsh and Gary D. Clow and Christian H. Fritsen and Christopher P. McKay and Andrew N. Parsons and Peter T. Doran and John C. Priscu and W. Berry Lyons and Andrew G Fountain and Diane M. McKnight and Daryl L. Moorhead and Ross A. Virginia and Diana H. Wall} } @article {1376, title = {Snow patch influence on soil biogeochemical processes and invertebrate distribution in the McMurdo Dry Valleys, Antarctica}, journal = {Arctic, Antarctic, and Alpine Research}, volume = {35}, year = {2002}, month = {02/2003}, pages = {91-99}, type = {Journal}, keywords = {LTER-MCM, Biggie}, doi = {10.1657/1523-0430(2003)035[0091:SPIOSB]2.0.CO;2}, url = {http://instaar.metapress.com/content/r086455ju7213711/}, author = {Michael N. Gooseff and John E. Barrett and Peter T. Doran and Andrew G Fountain and W. Berry Lyons and Andrew N. Parsons and Porazinska, D and Ross A. Virginia and Diana H. Wall} } @article {1374, title = {Valley floor climate observations from the McMurdo Dry Valleys, Antarctica, 1986-2000}, journal = {Journal of Geophysical Research}, volume = {107}, year = {2002}, month = {12/2002}, pages = {4772-4784}, type = {Journal}, abstract = {

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

}, keywords = {LTER-MCM, Biggie}, doi = {10.1029/2001JD002045}, author = {Peter T. Doran and Christopher P. McKay and Gary D. Clow and Gayle L. Dana and Andrew G Fountain and Thomas H. Nylen and W. Berry Lyons} } @article {1403, title = {Luminescence zeroing tests in Lake Hoare, Taylor Valley, Antarctica}, journal = {Journal of Paleolimnology}, volume = {25}, year = {2001}, pages = {519-529}, keywords = {LTER-MCM}, author = {G. W. Berger and Peter T. Doran} } @article {1404, title = {The McMurdo Dry Valleys Long-Term Ecological Research Program: new understanding of the biogeochemistry of the Dry Valley lakes: a review.}, journal = {Polar Geography}, volume = {25}, year = {2001}, pages = {202-217}, keywords = {LTER-MCM}, author = {W. Berry Lyons and Kathleen A. Welch and John C. Priscu and Johanna Laybourn-Parry and Daryl L. Moorhead and Diane M. McKnight and Peter T. Doran and Martyn Tranter} } @article {1405, title = {Mineralogical 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 Mars}, journal = {Geochimica et Cosmochimica Acta}, volume = {65}, year = {2001}, pages = {2875-2897}, keywords = {LTER-MCM}, author = {Bishop, Janice L. and Lougear, A and Newton, J and Peter T. Doran and Froeschl, H and Krner, W and Koeberl, C and Trautwein, A} } @article {1408, title = {Spectrofluorometric characterization of aquatic fulvic acid for determination of precursor organic material and general structural properties.}, journal = {Limnology and Oceanography}, volume = {46}, year = {2001}, pages = {38-48}, keywords = {LTER-MCM}, author = {Diane M. McKnight and Elizabeth W. Boyer and Paul K. Westerhoff and Peter T. Doran and Thomas Kulbe and Dale T. Andersen} } @inbook {1426, title = {Climate and hydrologic variations and implications for lake and stream ecological response in the McMurdo Dry Valleys, Antarctica}, booktitle = {Climate Variability and Ecosystem Response at Long Term Ecological Research Sites}, year = {2000}, pages = {174-195}, publisher = {Oxford University Press}, organization = {Oxford University Press}, keywords = {LTER-MCM}, author = {Kathleen A. Welch and W. Berry Lyons and Diane M. McKnight and Chris Jaros and Andrew G Fountain and Thomas H. Nylen and Peter T. Doran and Clive Howard-Williams}, editor = {D. Greenland and D. G. Goodin and R. C. Smith} } @article {1430, title = {Fossil fuel burning in Taylor Valley, southern Victoria Land, Antarctica: estimating the role of scientific activities on carbon and nitrogen reservoirs and fluxes}, journal = {Environmental Science and Technology}, volume = {34}, year = {2000}, pages = {1659-1662}, keywords = {LTER-MCM}, author = {W. Berry Lyons and C. A. Nezat and Kathleen A. Welch and Kottmeier, S and Peter T. Doran} } @article {1432, title = {The importance of landscape position and legacy: The evolution of the Taylor Valley Lake District, Antarctica.}, journal = {Freshwater Biology}, volume = {43}, year = {2000}, pages = {355-367}, keywords = {LTER-MCM}, author = {W. Berry Lyons and Andrew G Fountain and Peter T. Doran and John C. Priscu and Klaus Neumann and Kathleen A. Welch} } @inbook {1449, title = {Arctic and Antarctic lakes: contrast or continuum?}, booktitle = {Poles Apart: A Study in Contrasts}, year = {1999}, pages = {59-68}, publisher = {University of Ottawa Press}, organization = {University of Ottawa Press}, keywords = {LTER-MCM, Biggie}, author = {Peter T. Doran and Peter Adams and Ecclestone, M} } @article {1448, title = {Dating quaternary lacustrine sediments in the McMurdo Dry Valleys Antarctica}, journal = {Palaeography, Palaeoclimatology, Palaeoecology}, volume = {147}, year = {1999}, month = {03/1999}, pages = {223-239}, type = {Journal}, keywords = {LTER-MCM, sediments}, doi = {10.1016/S0031-0182(98)00159-X}, author = {Peter T. Doran and G. W. Berger and W. Berry Lyons and Robert A. Wharton Jr. and M. L. Davisson and J. Southon and J. E. Dibb} } @article {1457, title = {Effects of research diving on a stratified antarctic lake}, journal = {Water Research}, year = {1999}, keywords = {LTER-MCM}, author = {Kepner, R.L. and A. Kortyna and Robert A. Wharton Jr. and Peter T. Doran and Dale T. Andersen and Emily C. Roberts} } @proceedings {1465, title = {McMurdo Dry Valley Lakes: Impacts of Research Activities.}, year = {1999}, publisher = {Desert Research Institute, University and Community College System of Nevada, USA, special publication}, keywords = {LTER-MCM}, doi = {LTER}, author = {Robert A. Wharton Jr. and Peter T. Doran} } @article {1447, title = {Physical controls on the Taylor Valley Ecosystem, Antarctica}, journal = {BioScience}, volume = {49}, year = {1999}, month = {12/1999}, pages = {961-972}, type = {Journal}, keywords = {LTER-MCM, Water availability}, author = {Andrew G Fountain and W. Berry Lyons and Melody B. Burkins and Gayle L. Dana and Peter T. Doran and Karen J. Lewis and Diane M. McKnight and Daryl L. Moorhead and Andrew N. Parsons and John C. Priscu and Diana H. Wall and Robert A. Wharton Jr. and Ross A. Virginia} } @article {1483, title = {Antarctic paleolake sediments and the search for extinct life on Mars}, journal = {Journal of Geophysical Research-Planets}, volume = {103}, year = {1998}, month = {05/1998}, pages = {28481-28493}, keywords = {LTER-MCM}, doi = {10.1029/98JE01713}, author = {Peter T. Doran and Robert A. Wharton Jr. and David J. DesMarais and Christopher P. McKay} } @article {1496, title = {Evidence of deep circulation in two perennially ice-covered Antarctic lakes}, journal = {Limnol. Oceanogr.}, volume = {43}, year = {1998}, pages = {625-635}, keywords = {LTER-MCM}, author = {Scott W. Tyler and Peter G. Cook and Anya Z. Butt and James M. Thomas and Peter T. Doran and W. Berry Lyons} } @article {1484, title = {McMurdo Dry Valleys LTER: Geophysical determination of bathymetry and morphology of Taylor Valley lakes}, journal = {Antarctic Journal of the United States - 1996 Review Issue (NSF 98-28)}, volume = {31}, year = {1998}, month = {01/1996}, pages = {198-200}, keywords = {LTER-MCM}, author = {Peter T. Doran and Robert A. Wharton Jr. and Jeffrey P. Schmok} } @article {1482, title = {Perennial Antarctic Lake Ice: An Oasis for Life in a Polar Desert}, journal = {Science}, volume = {280}, year = {1998}, month = {06/1998}, pages = {2095-2098}, type = {Journal}, keywords = {LTER-MCM, Biggie}, doi = {10.1126/science.280.5372.2095}, url = {http://www.sciencemag.org/content/280/5372/2095.short}, author = {John C. Priscu and Christian H. Fritsen and Edward E. Adams and Stephen J. Giovannoni and Hans W. Paerl and Christopher P. McKay and Peter T. Doran and Douglas A. Gordon and Brian D. Lanoil and James L. Pinckney} } @inbook {1550, title = {Climate history of the McMurdo Dry Valleys since the last glacial maximum: A synthesis}, booktitle = {Ecosystem Processes in Antarctic Ice-free Landscapes}, year = {1997}, pages = {155-162}, publisher = {Balkema Press, Rotterdam}, organization = {Balkema Press, Rotterdam}, keywords = {LTER-MCM}, author = {W. Berry Lyons and Louis R. Bartek and Paul A. Mayewski and Peter T. Doran} } @article {1553, title = {Diatoms in sediments of perennially ice-covered Lake Hoare, and implications for interpreting lake history in the McMurdo Dry Valleys of Antarctica}, journal = {Journal of Paleolimnology}, volume = {17}, year = {1997}, pages = {403-420}, keywords = {LTER-MCM}, author = {Sarah A. Spaulding and Diane M. McKnight and E.F. Stoermer and Peter T. Doran} } @phdthesis {1577, title = {Paleolimnology of Perenially Ice-Covered Antarctic Oasis Lakes}, volume = {Ph.D.}, year = {1996}, school = {University of Nevada Reno}, type = {doctoral}, address = {Reno, NV}, keywords = {LTER-MCM}, author = {Peter T. Doran and Robert A. Wharton Jr.} } @article {1585, title = {A weather network in McMurdo Dry Valleys, Antarctica}, journal = {The Campbell Update}, volume = {7}, year = {1996}, pages = {3}, keywords = {LTER-MCM}, author = {Peter T. Doran} } @article {1588, title = {McMurdo Dry Valleys Long-Term Ecological Research (LTER): LTER automatic weather network (LAWN)}, journal = {Antarctic Journal of the U.S.}, volume = {30}, year = {1995}, pages = {276-280}, keywords = {LTER-MCM}, author = {Peter T. Doran and Gayle L. Dana and Hastings, Jordan Towner and Robert A. Wharton Jr.} } @article {1618, title = {McMurdo LTER: Paleolimnology of Taylor Valley, Antarctica}, journal = {Antarctic Journal of the United States}, volume = {29}, year = {1994}, pages = {234-237}, keywords = {LTER-MCM}, doi = {LTER}, author = {Peter T. Doran and Robert A. Wharton Jr. and Sarah A. Spaulding and J. S. Foster} } @article {1626, title = {Paleolimnology of the McMurdo Dry Valleys, Antarctica}, journal = {Journal of Paleolimnology}, volume = {10}, year = {1994}, pages = {85-114}, keywords = {LTER-MCM}, doi = {10.1007/BF00682507}, author = {Peter T. Doran and Robert A. Wharton Jr. and W. Berry Lyons} }