@article {5023, title = {Soil biota sensitivity to hydroclimate variability in a polar desert ecosystem}, journal = {Arctic, Antarctic, and Alpine Research}, volume = {57}, year = {2025}, month = {05/2025}, abstract = {

An anomalous warm weather event in the Antarctic McMurdo Dry Valleys on 18 March 2022 created an opportunity to characterize soil biota communities most sensitive to freeze\–thaw stress. This event caused unseasonal melt within Taylor Valley, activating stream water and microbial mats around Canada Stream. Liquid water availability in this polar desert is a driver of soil biota distribution and activity. Because climate change impacts hydrological regimes, we aimed to determine the effect on soil communities. We sampled soils identified from this event that experienced thaw, nearby hyper-arid areas, and wetted areas that did not experience thaw to compare soil bacterial and invertebrate communities. Areas that exhibited evidence of freeze\–thaw supported the highest live and dead nematode counts and were composed of soil taxa from hyper-arid landscapes and wetted areas. They received water inputs from snowpacks, hyporheic water, or glacial melt, contributing to community differences associated with organic matter and salinity gradients. Inundated soils had higher organic matter and lower conductivity (p \<\ .02) and hosted the most diverse microbial and invertebrate communities on average. Our findings suggest that as liquid water becomes more available under predicted climate change, soil communities adapted to the hyper-arid landscape will shift toward diverse, wetted soil communities.

}, keywords = {LTER-MCM, climate variation, extreme weather, McMurdo Dry Valleys, microbial community, soil invertebrates}, issn = {1523-0430}, doi = {10.1080/15230430.2025.2485283}, url = {https://www.tandfonline.com/doi/full/10.1080/15230430.2025.2485283}, author = {Snyder, Meredith D. and Adams, Byron J. and Borgmeier, Abigail and Jorna, Jesse and Power, Sarah N. and Salvatore, Mark R. and John E. Barrett} } @article {4935, title = {Sentinel protist taxa of the McMurdo Dry Valley lakes, Antarctica: A review}, journal = {Frontiers in Ecology and Evolution}, volume = {12}, year = {2024}, month = {03/2024}, pages = {1323472}, abstract = {

High-latitude meromictic lakes such as those in the Antarctic McMurdo Dry Valleys (MDV) harbor aquatic ecosystems dominated by the microbial loop. Within this habitat, which is limited year-round by light and nutrients, protists, or single celled eukaryotes, play outsized roles in the food web as the dominant primary producers and the apex predators. Thus, the MDV lake ecosystem represents an ideal system to study the role of sentinel protist taxa in carbon and nutrient cycling. The perennially ice-covered lakes are part of the McMurdo Long Term Ecological Research (McM LTER; mcmlter.org) established in 1993. In this review we will highlight the diversity and trophic roles of the MDV lake protist community and compare environmental factors driving spatiotemporal patterns in key protist taxa in two lakes within the McM LTER, Lakes Bonney and Fryxell. We will then discuss lessons learned from manipulated experiments on the impact of current and future climate-driven environmental change on sensitive protist taxa. Last, we will integrate knowledge gained from 25 years of lab-controlled experiments on key photosynthetic protists to extend our understanding of the function of these extremophiles within the MDV aquatic food webs. Our research group has studied the distribution and function of the MDV microbial community for nearly two decades, training the next generation of scientists to tackle future problems of these globally significant microbes. This review article will also highlight early career scientists who have contributed to this body of work and represent the future of scientific understanding in the Anthropocene.

}, keywords = {LTER-MCM, Antarctica, Disturbance, McMurdo Dry Valley lakes, phytoplankton, protist}, doi = {10.3389/fevo.2024.1323472}, url = {https://www.frontiersin.org/articles/10.3389/fevo.2024.1323472}, author = {Rachael M. Morgan-Kiss and Popson, Devon and Pereira, Rochelle and Dolhi-Binder, J and Teufel, Amber G. and Li, Wei and Kalra, Isha and Sherwell, Shasten S. and Reynebeau, Emily and Cristina D. Takacs-Vesbach} } @article {4866, title = {Sediment oxygen consumption in Antarctic subglacial environments}, journal = {Limnology and Oceanography}, volume = {68}, year = {2023}, month = {07/2023}, pages = {1557 - 1566}, abstract = {

Oxygen consumption in aquatic sediments is an indicator of overall biological activity of the ecosystem. As such, rates of sedimentary oxygen utilization are well documented for much of the open oceans and freshwater lakes. However, there are few direct measurements of sedimentary oxygen consumption from Antarctic subglacial aquatic sediments. We report the first microsensor oxygen profiles and derived sedimentary oxygen consumption rates from beneath the Ross Ice Shelf and a subglacial lake beneath the West Antarctic Ice Sheet. Rates of oxygen consumption in these two environments are relatively low, but comparable to those reported from ice-free polar oceans and oligotrophic Arctic lakes. Our study demonstrates the presence of oxygen within Antarctic subglacial aquatic sediments and its importance for oxygen-consuming microorganisms living in these ecosystems.

}, keywords = {LTER-MCM}, issn = {0024-3590}, doi = {10.1002/lno.12366}, url = {https://aslopubs.onlinelibrary.wiley.com/doi/10.1002/lno.12366}, author = {Alexander B. Michaud and John C. Priscu} } @mastersthesis {4857, title = {Snow distribution and influence in Taylor Valley, Antarctica, using remote sensing}, volume = {M.S.}, year = {2023}, month = {04/2023}, school = {Louisiana State University}, type = {masters}, address = {Baton Rouge, LA}, abstract = {

The McMurdo Dry Valleys is the largest ice-free area in Antarctica, but seasonal snow covers the valley floors sporadically throughout the year. In this study, a model to estimate areal snow coverage from satellite imagery was created. An area-volume model was created to estimate the amount of snow water equivalent (SWE) from the snow area extracted from the imagery. Snow cover influences the total albedo, the hydrologic budget, and the soil moisture and soil temperature in Taylor Valley (TV). Quantifying snow precipitation in TV is challenging because snow redistributes with winds, sublimates, or melts within a short period. Previous estimates found the amount of snow precipitation in TV is small, less than 100 mm/a. (SWE); even so, snow cover may influence processes in the valley. To better understand the controls and feedbacks of snow cover in the valley, a long-term record of spatially distributed abundance is required. This research creates a long-term record of snow cover data in TV using satellite images. The area of snowpacks was calculated by creating a classification scheme based on the brightness of panchromatic images. During the 2021-2022 field season, 250 m x 250 m sampling quadrats were surveyed to approximate how area and volume relate to SWE. Volumetric SWE was calculated by measuring in situ the length, width, depth, and density of each snowpack in the quadrat. There is a strong relationship between the area and the volume of the snowpacks (R2=0.942, P=0.182). With this information, estimates of the SWE can be made from the area calculated from satellite imagery. The average snow area for the entire extent of TV in late winter/early summer (September-December) from 2004 to 2022 is 65.26 km2, the average SWE is 0.0310 km3, and the average SWE depth is 75.72 mm. The amount of areal snow coverage is important when calculating the energy balance of TV, as well as understanding the availability of soil moisture to the soil ecosystem year-to-year. The available SWE can also influence seasonal surface and subsurface hydrology. While most precipitated snow in TV will sublimate or be redistributed by the wind, it is important to quantify how much snow has accumulated each season, especially with a warming climate, which could drastically influence snow accumulation and dynamics in TV.

}, keywords = {LTER-MCM}, url = {https://digitalcommons.lsu.edu/gradschool_theses/5749}, author = {McNulty, Katherine} } @article {4845, title = {Spatial patterns of major ions and their relationship to sediment concentration in near surface glacier ice, Taylor Valley Antarctica}, journal = {Journal of Geophysical Research: Earth Surface}, year = {2023}, month = {03/2024}, abstract = {

Glaciers form the headwaters of many watersheds and, in arid polar environments, can provide the vast majority of water to downstream systems. Headwater watersheds are critically important for setting the chemistry for downstream systems, yet we know comparatively little about the patterns and processes that generate the geochemical signature of meltwater on glacier surfaces. Here, we focus on glaciers in the McMurdo Dry Valleys of Antarctica, the largest ice-free area on the continent, characterized by alpine glaciers flowing into broad, rocky valleys. We examine patterns from the coast inland, accumulation to ablation zones, laterally across individual glaciers, and through the zone of meltwater generation. We directly compare solute to sediment concentrations, a major source of dissolved solutes. Our findings agree with previous work that the overall meltwater chemistry of a given glacier is a product local sediment sources and of regional wind patterns: foehn winds moving from the ice sheet to the coast and on-shore sea breezes. Further, these patterns hold across an individual glacier. Finally, we find that the ice chemistry and sediment profiles reflect freeze-thaw and melt processes that occur at depth. This indicates that the transport and weathering of sediment in the ice profile likely has a strong influence on supra- and proglacial stream chemistry. This new understanding strengthens connections between physical and geochemical processes in cold-based polar glacier environments and helps us better understand the processes driving landscape and ecosystem connectivity.

}, keywords = {LTER-MCM}, issn = {2169-9003}, doi = {10.1029/2022JF006980}, url = {https://onlinelibrary.wiley.com/doi/10.1029/2022JF006980}, author = {Bergstrom, Anna J. and Kathleen A. Welch and Michael N. Gooseff} } @article {4943, title = {Strong dispersal limitation of microbial communities at Shackleton Glacier, Antarctica}, journal = {mSystems}, volume = {8}, year = {2023}, month = {01/2023}, abstract = {

Microbial communities can be structured by both deterministic and stochastic processes, but the relative importance of these processes remains unknown. The ambiguity partly arises from an inability to disentangle soil microbial processes from confounding factors, such as aboveground plant communities or anthropogenic disturbance. In this study, we characterized the relative contributions of determinism and stochasticity to assembly processes of soil bacterial communities across a large environmental gradient of undisturbed Antarctic soils. We hypothesized that harsh soils would impose a strong environmental selection on microbial communities, whereas communities in benign soils would be structured largely by dispersal. Contrary to our expectations, dispersal was the dominant assembly mechanism across the entire soil environmental gradient, including benign environments. The microbial community composition reflects slowly changing soil conditions and dispersal limitation of isolated sites. Thus, stochastic processes, as opposed to deterministic, are primary drivers of soil ecosystem assembly across space at our study site. This is especially surprising given the strong environmental constraints on soil microorganisms in one of the harshest environments on the planet, suggesting that dispersal could be a driving force in microbial community assembly in soils worldwide.

}, keywords = {LTER-MCM, community assembly, determinism, dispersal, niche, stochasticity}, doi = {10.1128/msystems.01254-22}, url = {https://journals.asm.org/doi/full/10.1128/msystems.01254-22}, author = {Lemoine, Nathan P. and Byron Adams and Melisa A. Diaz and Dragone, Nicholas B. and Franco, Andr{\'e} L. C. and Noah Fierer and W. Berry Lyons and Hogg, Ian D. and Diana H. Wall}, editor = {Lurgi, Miguel} } @phdthesis {4692, title = {Stream corridor connectivity controls on nitrogen cycling}, volume = {PhD}, year = {2021}, month = {05/2021}, school = {University of Colorado Boulder}, type = {Doctoral}, address = {Boulder, CO, USA}, abstract = {

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

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

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

}, keywords = {LTER-MCM, Antarctica, hyporheic zone, nitrogen cycling, streams}, url = {https://www.proquest.com/docview/2572593127}, author = {Singley, Joel G.}, editor = {Eve-Lyn S. Hinckley and Michael N. Gooseff} } @article {4648, title = {Supporting simultaneous air revitalization and thermal control in a crewed habitat with temperate Chlorella vulgaris and eurythermic Antarctic Chlorophyta}, journal = {Frontiers in Microbiology}, volume = {12}, year = {2021}, month = {08/2021}, pages = {709746}, abstract = {

Including a multifunctional, bioregenerative algal photobioreactor for simultaneous air revitalization and thermal control may aid in carbon loop closure for long-duration surface habitats. However, using water-based algal media as a cabin heat sink may expose the contained culture to a dynamic, low temperature environment. Including psychrotolerant microalgae, native to these temperature regimes, in the photobioreactor may contribute to system stability. This paper assesses the impact of a cycled temperature environment, reflective of spacecraft thermal loops, to the oxygen provision capability of temperate Chlorella vulgaris and eurythermic Antarctic Chlorophyta. The tested 28-min temperature cycles reflected the internal thermal control loops of the International Space Station (C. vulgaris, 9\–27\°C; Chlorophyta-Ant, 4\–14\°C) and included a constant temperature control (10\°C). Both sample types of the cycled temperature condition concluded with increased oxygen production rates (C. vulgaris; initial: 0.013 mgO2 L-1, final: 3.15 mgO2 L\–1 and Chlorophyta-Ant; initial: 0.653 mgO2 L\–1, final: 1.03 mgO2 L\–1) and culture growth, suggesting environmental acclimation. Antarctic sample conditions exhibited increases or sustainment of oxygen production rates normalized by biomass dry weight, while both C. vulgaris sample conditions decreased oxygen production per biomass. However, even with the temperature-induced reduction, cycled temperature C. vulgaris had a significantly higher normalized oxygen production rate than Antarctic Chlorophyta. Chlorophyll fluorometry measurements showed that the cycled temperature conditions did not overly stress both sample types (FV/FM: 0.6\–0.75), but the Antarctic Chlorophyta sample had significantly higher fluorometry readings than its C. vulgaris counterpart (F = 6.26, P \< 0.05). The steady state C. vulgaris condition had significantly lower fluorometry readings than all other conditions (FV/FM: 0.34), suggesting a stressed culture. This study compares the results to similar experiments conducted in steady state or diurnally cycled temperature conditions. Recommendations for surface system implementation are based off the presented results. The preliminary findings imply that both C. vulgaris and Antarctic Chlorophyta can withstand the dynamic temperature environment reflective of a thermal control loop and these data can be used for future design models.

}, keywords = {LTER-MCM, air revitalization, Antarctica, bioregenerative life support systems, Chlorophyta, McMurdo Dry Valleys, thermal control}, doi = {10.3389/fmicb.2021.709746}, url = {https://www.frontiersin.org/article/10.3389/fmicb.2021.709746}, author = {Matula, Emily E. and Nabity, James A. and Diane M. McKnight} } @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 {4490, title = {Shotgun metagenomics reveal a diverse assemblage of protists in a model Antarctic soil ecosystem}, journal = {Environmental Microbiology}, year = {2020}, month = {08/2020}, abstract = {

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

}, keywords = {LTER-MCM, Antarctica, extremophiles, functional groups, metagenomics, protozoa, soil microbiology}, doi = {10.1111/1462-2920.15198}, url = {https://sfamjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1462-2920.15198}, author = {Thompson, Andrew R. and Geisen, Stefan and Byron Adams} } @article {4463, title = {Silicon isotopes reveal a non-glacial source of silicon to Crescent Stream, McMurdo Dry Valleys, Antarctica}, journal = {Frontiers in Earth Science}, volume = {8}, year = {2020}, month = {06/2020}, abstract = {

In high latitude environments, silicon is supplied to river waters by both glacial and non-glacial chemical weathering. The signal of these two end-members is often obscured by biological uptake and/or groundwater input in the river catchment. McMurdo Dry Valleys streams in Antarctica have no deep groundwater input, no connectivity between streams and no surface vegetation cover, and thus provide a simplified system for us to constrain the supply of dissolved silicon (DSi) to rivers from chemical weathering in a glacial environment. Here we report dissolved Si concentrations, germanium/silicon ratios (Ge/Si) and silicon isotope compositions (δ30SiDSi) in Crescent Stream, McMurdo Dry Valleys for samples collected between December and February in the 2014\−2015, 2015\−2016, and 2016\−2017 austral seasons. The δ30SiDSi compositions and DSi concentrations are higher than values reported in wet-based glacial meltwaters, and form a narrow cluster within the range of values reported for permafrost dominated Arctic Rivers. High\ δ30SiDSi\ compositions, ranging from +0.90\‰ to +1.39\‰, are attributed to (i) the precipitation of amorphous silica during freezing of waters in isolated pockets of the hyporheic zone in the winter and the release of Si from unfrozen pockets during meltwater-hyporheic zone exchange in the austral summer, and (ii) additional Si isotope fractionation via long-term Si uptake in clay minerals and seasonal Si uptake into diatoms superimposed on this winter-derived isotope signal. There is no relationship between\ δ30SiDSi\ compositions and DSi concentrations with seasonal and daily discharge, showing that stream waters contain DSi that is in equilibrium with the formation of secondary Si minerals in the hyporheic zone. We show that\ δ30SiDSi\ compositions can be used as tracers of silicate weathering in the hyporheic zone and possible tracers of freeze-thaw conditions in the hyporheic zone. This is important in the context of the ongoing warming in McMurdo Dry Valleys and the supply of more meltwaters to the hyporheic zone of McMurdo Dry Valley streams.

}, keywords = {LTER-MCM}, doi = {10.3389/feart.2020.00229}, url = {https://www.frontiersin.org/articles/10.3389/feart.2020.00229/full}, author = {Hirst, Catherine and Opfergelt, Sophie and Fran{\c c}ois Gaspard and Hendry, Katharine R. and Hatton, Jade E. and Sue Welch and Diane M. McKnight and W. Berry Lyons} } @article {4466, title = {Silicon isotopic composition of dry and wet-based glaciers in Antarctica}, journal = {Frontiers in Earth Science}, volume = {8}, year = {2020}, month = {07/2020}, abstract = {

Glaciers and ice sheets export significant amounts of silicon (Si) to downstream ecosystems, impacting local and potentially global biogeochemical cycles. Recent studies have shown Si in Arctic glacial meltwaters to have an isotopically distinct signature when compared to non-glacial rivers. This is likely linked to subglacial weathering processes and mechanochemical reactions. However, there are currently no silicon isotope (δ30Si) data available from meltwater streams in Antarctica, limiting the current inferences on global glacial silicon isotopic composition and its drivers. To address this gap, we present dissolved silicon (DSi), δ30SiDSi, and major ion data from meltwater streams draining a polythermal glacier in the region of the West Antarctic Peninsula (WAP; King George Island) and a cold-based glacier in East Antarctica [Commonwealth Stream, McMurdo Dry Valleys (MDV)]. These data, alongside other global datasets, improve our understanding of how contrasting glacier thermal regime can impact upon Si cycling and therefore the δ30SiDSi composition. We find a similar δ30SiDSi composition between the two sites, with the streams on King George Island varying between -0.23 and +1.23\‰ and the Commonwealth stream varying from -0.40 to +1.14\‰. However, meltwater streams in King George Island have higher DSi concentrations, and the two glacial systems exhibit opposite DSi \– δ30SiDSi trends. These contrasts likely result from differences in weathering processes, specifically the role of subglacial processes (King George Island) and, supraglacial processes followed by in-stream weathering in hyporheic zones (Commonwealth Stream). These findings are important when considering likely changes in nutrient fluxes from Antarctic glaciers under climatic warming scenarios and consequent shifts in glacial thermal regimes.

}, keywords = {LTER-MCM}, doi = {10.3389/feart.2020.00286}, url = {https://www.frontiersin.org/articles/10.3389/feart.2020.00286/full}, author = {Hatton, Jade E. and Hendry, Katharine R. and Hirst, Catherine and Opfergelt, Sophie and Henkel, Susann and Silva-Busso, Adri{\'a}n and Welch, Susan A. and Wadham, Jemma L. and W. Berry Lyons and Bagshaw, Elizabeth and Staubwasser, Michael and Diane M. McKnight} } @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 {4295, title = {Soil nematode abundance and functional group composition at a global scale}, journal = {Nature}, volume = {572}, year = {2019}, month = {08/2019}, abstract = {

Soil organisms are a crucial part of the terrestrial biosphere. Despite their importance for ecosystem functioning, few quantitative, spatially explicit models of the active belowground community currently exist. In particular, nematodes are the most abundant animals on Earth, filling all trophic levels in the soil food web. Here we use 6,759 georeferenced samples to generate a mechanistic understanding of the patterns of the global abundance of nematodes in the soil and the composition of their functional groups. The resulting maps show that 4.4 \± 0.64 \× 1020 nematodes (with a total biomass of approximately 0.3 gigatonnes) inhabit surface soils across the world, with higher abundances in sub-Arctic regions (38\% of total) than in temperate (24\%) or tropical (21\%) regions. Regional variations in these global trends also provide insights into local patterns of soil fertility and functioning. These high-resolution models provide the first steps towards representing soil ecological processes in global biogeochemical models and will enable the prediction of elemental cycling under current and future climate scenarios.

}, keywords = {LTER-MCM}, doi = {10.1038/s41586-019-1418-6}, url = {https://www.nature.com/articles/s41586-019-1418-6}, author = {van den Hoogen, Johan and Geisen, Stefan and Routh, Devin and Ferris, Howard and Traunspurger, Walter and Wardle, D and de Goede, Ron G. M. and Byron Adams and Ahmad, Wasim and Andriuzzi, Walter S. and Richard D. Bardgett and Bonkowski, Michael and Campos-Herrera, Raquel and Cares, Juvenil E. and Caruso, Tancredi and de Brito Caixeta, Larissa and Chen, Xiaoyun and Costa, Sofia R. and Creamer, Rachel and Mauro da Cunha Castro, Jos{\'e} and Dam, Marie and Djigal, Djibril and Escuer, Miguel and Griffiths, Bryan S. and Guti{\'e}rrez, Carmen and Hohberg, Karin and Kalinkina, Daria and Kardol, Paul and Kergunteuil, Alan and Korthals, Gerard and Krashevska, Valentyna and Kudrin, Alexey A. and Li, Qi and Liang, Wenju and Magilton, Matthew and Marais, Mariette and Mart{\'\i}n, Jos{\'e} Antonio Rodr{\'\i}guez and Matveeva, Elizaveta and Mayad, El Hassan and Mulder, Christian and Mullin, Peter and Neilson, Roy and Nguyen, T. A. Duong and Uffe N. Nielsen and Okada, Hiroaki and Rius, Juan Emilio Palomares and Pan, Kaiwen and Peneva, Vlada and Pellissier, Lo{\"\i}c and Carlos Pereira da Silva, Julio and Pitteloud, Camille and Powers, Thomas O. and Powers, Kirsten and Quist, Casper W. and Rasmann, Sergio and Moreno, Sara S{\'a}nchez and Scheu, Stefan and Set{\"a}l{\"a}, Heikki and Sushchuk, Anna and Tiunov, Alexei V. and Trap, Jean and van der Putten, W and Vesterg{\r a}rd, Mette and Villenave, Cecile and Waeyenberge, Lieven and Diana H. Wall and Wilschut, Rutger and Wright, Daniel G. and Yang, Jiue-in and Crowther, Thomas Ward} } @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 {4080, title = {Soil biological responses to C, N and P fertilization in a polar desert of Antarctica}, journal = {Soil Biology and Biochemistry}, volume = {122}, year = {2018}, month = {07/2018}, chapter = {7}, abstract = {

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

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

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

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

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

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

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

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

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

}, keywords = {LTER-MCM, ecological stoichiometry, Lake Fryxell Basin, McMurdo Dry Valleys, network community modeling, nutrient colimitation, Solirubrobacteriaceae}, doi = {10.3389/fmicb.2018.01401}, url = {https://www.frontiersin.org/article/10.3389/fmicb.2018.01401/full}, author = {Aanderud, Zachary T. and Saurey, Sabrina D. and Ball, Becky and Diana H. Wall and John E. Barrett and Muscarella, Mario E. and Griffin, Natasha A. and Ross A. Virginia and Byron Adams} } @article {3965, title = {A simulation-based approach to understand how metacommunity characteristics influence emergent biodiversity patterns}, journal = {Oikos}, volume = {126}, year = {2017}, month = {05/2017}, pages = {723-737}, abstract = {

To understand controls over biodiversity, it is necessary to take a multi-scale approach to understand how local and regional factors a ect the community assembly processes that drive emergent patterns. \ is need is re ected in the growing use of the metacommunity concept to interpret multi-scale measures of biodiversity, including metrics derived from diversity partitioning (e.g. a, b and g diversity) and variation partitioning (e.g. spatial and environmental components of compositional turnover) techniques. However, studies have shown limited success using these metrics to characterize underlying community assembly dynamics. Here we demonstrate how a metacommunity simulation package (MCSim) can be used to evaluate when and how biodiversity metrics can be used to make inferences about metacommunity characteristics. We examined a wide range of parameter settings representing ecologically relevant scenarios. We used artificial neural networks (ANNs) to assess the sensitivity of diversity and variation partitioning metrics (calculated from simulation outcomes) to metacommunity parameter settings. In the scenarios examined in this study, the niche-neutral gradient strongly in uenced most biodiversity metrics, metacommunity size exhibited a marginal influence over some metrics, and dispersal dynamics only a ected a subset of variation partitioning outcomes. Variation partitioning response curves along the niche-neutral gradient were not monotonic; however, simulation outcomes suggest other biodiversity metrics (e.g. dissimilarity saturation) can be used in combination with variation partitioning metrics to make inferences about metacommunity properties. With the growing availability of archived ecological data, we expect future work will apply simulation-based techniques to better understand links between biodiversity and the metacommunity characteristics that are presumed to control the underlying community assembly processes.

}, keywords = {LTER-MCM}, doi = {10.1111/oik.03690}, url = {http://doi.wiley.com/10.1111/oik.03690}, author = {Eric R. Sokol and Brown, Bryan L. and John E. Barrett} } @mastersthesis {4065, title = {Spatial and Temporal Geochemical Characterization of Aeolian Material from the McMurdo Dry Valleys, Antarctica}, volume = {M.S.}, year = {2017}, school = {Ohio State University}, type = {masters}, abstract = {

Aeolian processes play an important role in the transport of both geological and biological materials globally, on the biogeochemistry of ecosystems, and in landscape evolution. As the largest ice free area on the Antarctic continent (approximately 4800 km2), the McMurdo Dry Valleys (MDV) are potentially a major source of aeolian material for Antarctica, but information on the spatial and temporal variability of this material is needed to understand its soluble and bulk geochemistry, deposition and source, and hence influence on ecosystem dynamics. 53 samples of aeolian material from Alatna Valley, Victoria Valley, Miers Valley, and Taylor Valley (Taylor Glacier, East Lake Bonney, F6 (Lake Fryxell), and Explorer\’s Cove) were collected at five heights (5, 10, 20, 50, 100 cm) above the surface seasonally for 2013 through 2015. The sediment was analyzed for soluble solids, total and organic carbon, minerology, and bulk chemistry. Of the soluble component, the major anions varied between Cl- and HCO3-, and the major cation was Na+ for all sites. Soluble N:P ratios in the aeolian material reflect nutrient limitations seen in MDV soils, where younger, coastal soils are N-limited, while older, up valley soils are P-limited. Material from East Lake Bonney was P-limited in the winter samples, but N-limited in the full year samples, suggesting different sources of material based on season. Analysis of soluble salts in aeolian material in Taylor Valley compared to published soil literature demonstrates a primarily down valley transport of materials from Taylor Glacier towards the coast. The bulk chemistry suggests that the aeolian material is highly unweathered (CIA values less than 60 \%), but scanning electron microscope images show alteration for some individual sediment grains. The mineralogy was reflective of local rocks, specifically the McMurdo Volcanics, Ferrar Dolerite, Beacon Sandstone and granite, but variations in major oxide percentages and rare earth element signatures could not be explained by mixing lines between these four rock types. This potentially suggests that there may be an additional, and possibly distant, source of aeolian material to the MDV that is not accounted for. This work provides the first fully elevated spatial and temporal analysis of the geochemistry of aeolian material from the Dry Valleys, and contributes to a better understanding of sediment provenance and how aeolian deposition may affect surface biological communities.

}, keywords = {LTER-MCM}, url = {http://rave.ohiolink.edu/etdc/view?acc_num=osu1500468216147725}, author = {Melisa A. Diaz}, editor = {W. Berry Lyons} } @article {3875, title = {Stream biogeochemical and suspended sediment responses to permafrost degradation in stream banks in Taylor Valley, Antarctica}, journal = {Biogeosciences}, volume = {13}, year = {2016}, month = {03/2016}, pages = {1723 - 1732}, abstract = {

\ Stream channels in the McMurdo Dry Valleys are characteristically wide, incised, and stable. At typical flows, streams occupy a fraction of the oversized channels, providing habitat for algal mats. In January 2012, we discovered substantial channel erosion and subsurface thermomechanical erosion undercutting banks of the Crescent Stream. We sampled stream water along the impacted reach and compared concentrations of solutes to the long-term data from this stream (\ \∼\  20 years of monitoring). Thermokarst-impacted stream water demonstrated higher electrical conductivity, and concentrations of chloride, sulfate, sodium, and nitrate than the long-term medians. These results suggest that this mode of lateral permafrost degradation may substantially impact stream solute loads and potentially fertilize stream and lake ecosystems. The potential for sediment to scour or bury stream algal mats is yet to be determined, though it may offset impacts of associated increased nutrient loads to streams.

}, keywords = {LTER-MCM}, doi = {10.5194/bg-13-1723-2016}, url = {http://www.biogeosciences.net/13/1723/2016/bg-13-1723-2016.pdf}, author = {Michael N. Gooseff and David J. Van Horn and Sudman, Zachary and Diane M. McKnight and Kathleen A. Welch and W. Berry Lyons} } @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 {3532, title = {Soil biodiversity and human health}, journal = {Nature}, year = {2015}, month = {11/2015}, keywords = {LTER-MCM}, issn = {0028-0836}, doi = {10.1038/nature15744}, url = {http://www.nature.com/doifinder/10.1038/nature15744}, author = {Diana H. Wall and Uffe N. Nielsen and Six, Johan} } @article {1066, title = {Spatiotemporal Dynamics of Wetted Soils across a Polar Desert Landscape, McMurdo Dry Valleys Antarctica}, journal = {Antarctic Science}, volume = {27}, year = {2015}, month = {04/2015}, pages = {197-209}, chapter = {197}, abstract = {Liquid water is scarce across the landscape of the McMurdo Dry Valleys (MDV), Antarctica, a 3800 km2 ice-free region, and is chiefly associated with soils that are adjacent to streams and lakes (i.e. wetted margins) during the annual thaw season. However, isolated wetted soils have been observed at locations distal from water bodies. The source of water for the isolated patches of wet soil is potentially generated by a combination of infiltration from melting snowpacks, melting of pore ice at the ice table, and melting of buried segregation ice formed during winter freezing. High resolution remote sensing data gathered several times per summer in the MDV region were used to determine the spatial and temporal distribution of wet soils. The spatial consistency with which the wet soils occurred was assessed for the 2009{\textendash}10 to 2011{\textendash}12 summers. The remote sensing analyses reveal that cumulative area and number of wet soil patches varies among summers. The 2010{\textendash}11 summer provided the most wetted soil area (10.21 km2) and 2009{\textendash}10 covered the least (5.38 km2). These data suggest that wet soils are a significant component of the MDV cold desert land system and may become more prevalent as regional climate changes.}, keywords = {LTER-MCM}, doi = {10.1017/S0954102014000601}, url = {http://dx.doi.org/10.1017/S0954102014000601}, author = {Langford, Z. L. and Michael N. Gooseff and Lampkin, Derrick J.} } @article {3220, title = {Soil animal responses to moisture availability are largely scale, not ecosystem dependent: insight from a cross-site study}, journal = {Global Change Biology}, volume = {20}, year = {2014}, month = {08/2014}, pages = {2631 - 2643}, chapter = {2631}, abstract = {

Climate change will result in reduced soil water availability in much of the world either due to changes in precipitation or increased temperature and evapotranspiration. How communities of mites and nematodes may respond to changes in moisture availability is not well known, yet these organisms play important roles in decomposition and nutrient cycling processes. We determined how communities of these organisms respond to changes in moisture availability and whether common patterns occur along fine-scale gradients of soil moisture within four individual ecosystem types (mesic, xeric and arid grasslands and a polar desert) located in the western United States and Antarctica, as well as across a cross-ecosystem moisture gradient (CEMG) of all four ecosystems considered together. An elevation transect of three sampling plots was monitored within each ecosystem and soil samples were collected from these plots and from existing experimental precipitation manipulations within each ecosystem once in fall of 2009 and three times each in 2010 and 2011. Mites and nematodes were sorted to trophic groups and analyzed to determine community responses to changes in soil moisture availability. We found that while both mites and nematodes increased with available soil moisture across the CEMG, within individual ecosystems, increases in soil moisture resulted in decreases to nematode communities at all but the arid grassland ecosystem; mites showed no responses at any ecosystem. In addition, we found changes in proportional abundances of mite and nematode trophic groups as soil moisture increased within individual ecosystems, which may result in shifts within soil food webs with important consequences for ecosystem functioning. We suggest that communities of soil animals at local scales may respond predictably to changes in moisture availability regardless of ecosystem type but that additional factors, such as climate variability, vegetation composition, and soil properties may influence this relationship over larger scales.

}, keywords = {LTER-MCM}, doi = {10.1111/gcb.2014.20.issue-810.1111/gcb.12522}, url = {http://doi.wiley.com/10.1111/gcb.2014.20.issue-8http://doi.wiley.com/10.1111/gcb.12522}, author = {Sylvain, Zachary A. and Diana H. Wall and Cherwin, Karie L. and Debra P. C. Peters and Reichmann, Lara G. and Osvaldo E. Sala} } @article {1064, title = {Soil microbial responses to increased moisture and organic resources along a salinity gradient in a polar desert.}, journal = {Applied and Environmental Microbiology.}, volume = {80}, year = {2014}, month = {05/2014}, pages = {3034-3043}, chapter = {3034}, abstract = {Microbial communities in extreme environments often have low diversity and specialized physiologies suggesting a limited resistance to change. The McMurdo Dry Valleys (MDV) are a microbially dominated, extreme ecosystem currently undergoing climate change-induced disturbances, including the melting of massive buried ice, cutting through of permafrost by streams, and warming events. These processes are increasing moisture across the landscape, altering conditions for soil communities by mobilizing nutrients and salts and stimulating autotrophic carbon inputs to soils. The goal of this study was to determine the effects of resource addition (water/organic matter) on the composition and function of microbial communities in the MDV along a natural salinity gradient representing an additional gradient of stress in an already extreme environment. Soil respiration and the activity of carbon-acquiring extracellular enzymes increased significantly (P < 0.05) with the addition of resources at the low- and moderate-salinity sites but not the high-salinity site. The bacterial community composition was altered, with an increase in Proteobacteria and Firmicutes with water and organic matter additions at the low- and moderate-salinity sites and a near dominance of Firmicutes at the high-salinity site. Principal coordinate analyses of all samples using a phylogenetically informed distance matrix (UniFrac) demonstrated discrete clustering among sites (analysis of similarity [ANOSIM], P < 0.05 and R > 0.40) and among most treatments within sites. The results from this experimental work suggest that microbial communities in this environment will undergo rapid change in response to the altered resources resulting from climate change impacts occurring in this region.}, keywords = {LTER-MCM}, doi = {10.1128/AEM.03414-13}, author = {David J. Van Horn and Okie, J.G. and Heather N. Buelow and Michael N. Gooseff and John E. Barrett and Cristina D. Takacs-Vesbach} } @article {3219, title = {The spatial structure of Antarctic biodiversity}, journal = {Ecological Monographs}, volume = {84}, year = {2014}, month = {05/2014}, pages = {203 - 244}, abstract = {

Patterns of environmental spatial structure lie at the heart of the most fundamental and familiar patterns of diversity on Earth. Antarctica contains some of the strongest environmental gradients on the planet and therefore provides an ideal study ground to test hypotheses on the relevance of environmental variability for biodiversity. To answer the pivotal question, \“How does spatial variation in physical and biological environmental properties across the Antarctic drive biodiversity?\” we have synthesized current knowledge on environmental variability across terrestrial, freshwater, and marine Antarctic biomes and related this to the observed biotic patterns. The most important physical driver of Antarctic terrestrial communities is the availability of liquid water, itself driven by solar irradiance intensity. Patterns of biota distribution are further strongly influenced by the historical development of any given location or region, and by geographical barriers. In freshwater ecosystems, free water is also crucial, with further important influences from salinity, nutrient availability, oxygenation, and characteristics of ice cover and extent. In the marine biome there does not appear to be one major driving force, with the exception of the oceanographic boundary of the Polar Front. At smaller spatial scales, ice cover, ice scour, and salinity gradients are clearly important determinants of diversity at habitat and community level. Stochastic and extreme events remain an important driving force in all environments, particularly in the context of local extinction and colonization or recolonization, as well as that of temporal environmental variability. Our synthesis demonstrates that the Antarctic continent and surrounding oceans provide an ideal study ground to develop new biogeographical models, including life history and physiological traits, and to address questions regarding biological responses to environmental variability and change.

}, keywords = {LTER-MCM}, issn = {0012-9615}, doi = {10.1890/12-2216.1}, url = {http://www.esajournals.org/doi/abs/10.1890/12-2216.1}, author = {Peter Convey and Steven L. Chown and Clarke, Andrew and Barnes, David K. A. and Bokhorst, Stef and Vonda Cummings and Hugh W. Ducklow and Francesco Frati and Green, T. G. Allan and Shulamit Gordon and Griffiths, Huw J. and Clive Howard-Williams and Huiskes, Ad H. L. and Johanna Laybourn-Parry and W. Berry Lyons and McMinn, Andrew and Morley, Simon A. and Lloyd S. Peck and Quesada, Antonio and Robinson, Sharon A. and Schiaparelli, Stefano and Diana H. Wall} } @article {3206, title = {Spring thaw ionic pulses boost nutrient availability and microbial growth in entombed Antarctic Dry Valley cryoconite holes}, journal = {Frontiers in Microbiology}, volume = {5}, year = {2014}, month = {12/2014}, abstract = {

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

}, keywords = {LTER-MCM}, doi = {10.3389/fmicb.2014.00694}, url = {http://journal.frontiersin.org/article/10.3389/fmicb.2014.00694/abstract}, author = {Telling, J. and Alexandre M. Anesio and Martyn Tranter and Andrew G Fountain and Thomas H. Nylen and Hawkings, Jon and Singh, Virendra B. and Kaur, Preeti and Musilova, Michaela and Wadham, J. L.} } @article {1089, title = {Seasonal controls on snow distribution and aerial ablation at the snow-patch and landscape scales, McMurdo Dry Valleys, Antarctica}, journal = {The Cryosphere}, volume = {7}, year = {2013}, month = {09/2013}, pages = {917 - 931}, keywords = {LTER-MCM}, doi = {10.5194/tc-7-917-2013}, url = {http://www.the-cryosphere.net/7/917/2013/tc-7-917-2013.html}, author = {Eveland, Jeffery and Michael N. Gooseff and Lampkin, Derrick J. and John E. Barrett and Cristina D. Takacs-Vesbach} } @article {1096, title = {Shallow groundwater systems in a polar desert, McMurdo Dry Valleys}, journal = {Hydrogeology Journal}, volume = {21}, year = {2013}, month = {02/2013}, pages = {171 - 183}, keywords = {LTER-MCM}, doi = {10.1007/s10040-012-0926-3}, url = {http://link.springer.com/article/10.1007\%2Fs10040-012-0926-3}, author = {Michael N. Gooseff and John E. Barrett and Joseph S. Levy} } @article {1090, title = {Spatial and temporal patterns of snow accumulation and aerial ablation across the McMurdo Dry Valleys, Antarctica}, journal = {Hydrological Processes}, volume = {27}, year = {2013}, month = {09/2013}, pages = {2864 - 2875}, keywords = {LTER-MCM}, doi = {10.1002/hyp.9407}, url = {http://onlinelibrary.wiley.com/doi/10.1002/hyp.9407/pdf}, author = {Eveland, Jeffery and Michael N. Gooseff and Lampkin, Derrick J. and John E. Barrett and Cristina D. Takacs-Vesbach} } @article {4062, title = {Seismic multiplet response triggered by melt at Blood Falls, Taylor Glacier, Antarctica}, journal = {Journal of Geophysical Research: Earth Surface}, volume = {117}, year = {2012}, month = {07/2012}, abstract = {

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

}, keywords = {LTER-MCM}, doi = {10.1029/2011JF002221}, url = {http://onlinelibrary.wiley.com/doi/10.1029/2011JF002221/full}, author = {Carmichael, J. D. and Pettit, E. and Hoffman, M and Andrew G Fountain and Hallet, B.} } @mastersthesis {4171, title = {Snow dynamics in a polar desert, McMurdo Dry Valleys, Antarctica}, volume = {M.S.}, year = {2012}, month = {2012}, school = {Pennsylvania State University}, type = {masters}, abstract = {

Snow in the McMurdo Dry Valleys is rare source of moisture for subnivian soils (beneath snow) in a cold desert ecosystem. While sublimation dominates the ablation process, measurable increases in soil moisture are expected to provide more favorable conditions for subnivian soil communities. In addition, snow cover insulates the underlying soil from temperature extremes. Quantifying the spatial distribution and ablation patterns of seasonal snow is necessary to understand these dynamics. Annual snowfall varies spatially ranging from 3 to 50 mm of snow water equivalent, with greater amounts occurring at the coast. Despite receiving very little precipitation, significant amounts of snow can accumulate (via aeolian redistribution) in topographic lees at the valley bottoms, forming thousands of discontinuous patches (typically 1-100 m2 in area). These patches have the potential to act as fertility islands, controlling the landscape distribution of microbial communities, and biogeochemical cycling.

High resolution imagery acquired during the 2009-2010 and 2010-2011 austral summers was used to quantify the distribution of snow across Taylor and Wright Valleys. An object-based classification was used to extract snow-covered area from the imagery. Coupled with topographic parameters, unique distribution patterns were characterized for 5 regions within the neighboring valleys. Time lapses of snow distribution during each season in each region provide insight into spatially characterizing the aerial ablation rates (change in area of landscape covered by snow) across the valleys. The distribution of snow-covered area during the 2009-2010 austral summer is used as a baseline for seasonal comparison. The surrounding regions of Lake Fryxell, Lake Hoare, Lake Bonney, Lake Brownworth, and Lake Vanda exhibited losses of snow-covered area of 9.61 km2 (-93\%), 1.63 km2 (-72\%), 1.07 km2 (-97\%), 2.60 km2 (-82\%), and 0.25 km2 (- 96\%) respectively, as measured from peak accumulation in October to mid-January during the\ 2009-2010 season. Differences in aerial ablation rates within and across local regions suggest that both topographic variation and regional microclimates influence the ablation of seasonal snow cover. Elevation has shown to be the strongest control over aerial ablation. Fifteen 1 km2 plots (3 in each region) were selected to assess the prevalence of snow cover at smaller scales. Results confirm that snow patches form in the same locations each year with some minor deviations observed. Stable isotopes from snow patches also provide insights into temporal and spatial processes associated with ablation. At the snow patch scale, neighboring patches often exhibit considerable differences in aerial ablation rates, presumably controlled by snow depth. This highlights the importance of both the landscape and snow patch scales in assessing the effects of snow cover on biogeochemical cycling and microbial communities.

}, keywords = {LTER-MCM}, url = {https://etda.libraries.psu.edu/catalog/12680}, author = {Eveland, Jeffery and Michael N. Gooseff} } @article {1129, title = {Simulating unsteady flow, anabranching, and hyporheic dynamics in a glacial meltwater stream using a coupled surface water routing and groundwater flow model}, journal = {Water Resources Research}, volume = {47}, year = {2011}, month = {2011}, keywords = {LTER-MCM}, doi = {10.1029/2010WR009508}, author = {Koch, J. and Diane M. McKnight and Neupauer, R. M.} } @phdthesis {1141, title = {Spatial and Temporal Variability of Glacier Melt in the McMurdo Dry Valleys, Antarctica}, volume = {Ph.D.}, year = {2011}, month = {01/2011}, pages = {296}, school = {Portland State University}, type = {doctoral}, address = {Portland}, keywords = {LTER-MCM}, author = {Hoffman, M} } @book {1146, title = {Spectral Methods to Advance Understanding of Dissolved Organic Carbon Dynamics in Forested Catchments}, series = {Ecological StudiesForest Hydrology and Biogeochemistry}, volume = {216}, year = {2011}, pages = {117 - 135}, publisher = {Springer Netherlands}, organization = {Springer Netherlands}, address = {Dordrecht}, keywords = {LTER-MCM}, isbn = {978-94-007-1363-5}, doi = {10.1007/978-94-007-1363-5_6}, url = {http://www.springerlink.com/content/lv9365ml54192m29/}, author = {Rose M. Cory and Elizabeth W. Boyer and Diane M. McKnight}, editor = {Levia, Delphis F. and Carlyle-Moses, Darryl and Tanaka, Tadashi} } @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 {1176, title = {Sediment Melt Dynamics in Permanent Antarctic Lake Ice}, journal = {Arctic, Antarctic, and Alpine Research}, volume = {42}, year = {2010}, pages = {57-66}, keywords = {LTER-MCM}, doi = {10.1657/1938-4246-42.1.57}, url = {http://mcmlter.lternet.edu/reports/lakes/JepsenEtAl2010SedimentMeltMigration.pdf}, author = {Steven M. Jepsen and Edward E. Adams and John C. Priscu} } @article {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.} } @article {1166, title = {Snow in the McMurdo Dry Valleys, Antarctica.}, journal = {International Journal of Climatology}, volume = {30}, year = {2010}, month = {04/2010}, pages = {633-642}, type = {Journal}, abstract = {

Snowfall was measured at 11 sites in the McMurdo Dry Valleys to determine its magnitude, its temporal changes, and spatial patterns. Annual values ranged from 3 to 50 mm water equivalent with the highest values nearest the coast and decreasing inland. A particularly strong spatial gradient exists in Taylor Valley, probably resulting from local uplift conditions at the coastal margin and valley topography that limits migration inland. More snow occurs in winter near the coast, whereas inland no seasonal pattern is discernable. This may be due, again, to local uplift conditions, which are common in winter. We find no influence of the distance to the sea ice edge. Katabatic winds play an important role in transporting snow to the valley bottoms and essentially double the precipitation. That much of the snow accumulation sublimates prior to making a hydrologic contribution underscores the notion that the McMurdo Dry Valleys are indeed an extreme polar desert. Copyright \© 2009 Royal Meteorological Society

}, keywords = {LTER-MCM, Biggie}, doi = {10.1002/joc.1933}, author = {Andrew G Fountain and Thomas H. Nylen and Andrew Monaghan and Hassan J. Basagic and David Bromwich} } @article {1154, title = {Spatial variations in the geochemistry of glacial meltwater streams in the Taylor Valley, Antarctica}, journal = {Antarctic Science}, volume = {22}, year = {2010}, month = {12/2010}, pages = {662 - 672}, keywords = {LTER-MCM}, doi = {10.1017/S0954102010000702}, url = {http://www.montana.edu/lkbonney/DOCS/Publications/WelchEtAl2010Geochemistry.pdf}, author = {Kathleen A. Welch and W. Berry Lyons and Whisner, Carla and Christopher B. Gardner and Michael N. Gooseff and Diane M. McKnight and John C. Priscu} } @article {1192, title = {The saline lakes of the McMurdo Dry Valleys, Antarctica,}, journal = {Aquatic Geochemistry}, year = {2009}, pages = {321-348}, keywords = {LTER-MCM}, doi = {LTER}, author = {William J. Green and W. Berry Lyons} } @article {1193, title = {Spatial variation in soil active-layer geochemistry across hydrologic margins in polar desert ecosystems.}, journal = {Hydrology and Earth System Sciences}, volume = {13}, year = {2009}, pages = {2349-2358}, keywords = {LTER-MCM}, doi = {LTER}, author = {John E. Barrett and Michael N. Gooseff and Cristina D. Takacs-Vesbach} } @article {1194, title = {State of the Antarctic and the Southern Ocean climate system,}, journal = {Review of Geophysics}, volume = {47}, year = {2009}, keywords = {LTER-MCM}, doi = {LTER}, author = {Paul A. Mayewski and David Bromwich and Campbell, H and Hamilton, G and W. Berry Lyons and Maasch, K and Aoki, S and Xiao, C and van Ommen, T and Meredith, M and Summerhayes, C and Turner, J and Worby, A and John E. Barrett and Casassa, G and Bertler, N and T Bracegirdle} } @article {1233, title = {Soil phosphorus cycling in an Antarctic polar desert}, journal = {Geochimica et Cosmochimica Acta}, volume = {144}, year = {2008}, pages = {21-32}, keywords = {LTER-MCM}, doi = {LTER}, author = {D. Brad Bate and John E. Barrett and Poage, M and Ross A. Virginia} } @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 {1224, title = {Stoichiometry of soil enzyme activity at global scale.}, journal = {Ecology Letters}, volume = {11}, year = {2008}, pages = {1252-1264}, keywords = {LTER-MCM}, doi = {LTER}, author = {Sinsabaugh, R and Gallo, M and Gartner, T and Hobbie, S and Holland, K and Keeler, B and Powers, J and Stursova, M and Cristina D. Takacs-Vesbach and Waldrop, M and Wallenstein, M and Lauber, M and Zak, D and Lydia H. Zeglin and Weintraub, M and Ahmed, B and Allison, S and Crenshaw, C and Contosta, A and Cusack, D and Frey, S} } @article {1225, title = {Supersaturated N2O in a perennially ice-covered Antarctic lake: Molecular and stable isotopic evidence for a biogeochemical relict.}, journal = {Limnology and Oceanography}, volume = {53}, year = {2008}, pages = {2439-2450}, keywords = {LTER-MCM}, doi = {LTER}, url = {http://brent.xner.net/pdf/Priscu_etal2008_ELB-N2O.pdf}, author = {John C. Priscu and Brent C. Christner and John E. Dore and Marian B. Westley and Brian N. Popp and Karen L. Casciotti and W. Berry Lyons} } @article {1226, title = {Surface energy balance and melt thresholds over 11 years at Taylor Glacier, Antarctica}, journal = {Journal of Geophysical Research-Earth Surface}, volume = {113}, year = {2008}, keywords = {LTER-MCM}, doi = {10.1029/2008JF001029}, author = {Hoffman, M and Andrew G Fountain and Liston, G} } @mastersthesis {1255, title = {Soil organic matter sources and quality in the McMurdo Dry Valleys, Antarctica}, volume = {M.S.}, year = {2007}, school = {Dartmouth College}, type = {masters}, keywords = {LTER-MCM}, doi = {LTER}, author = {D. Brad Bate} } @article {1237, title = {Solute and isotope geochemistry of subsurface ice melt seeps in Taylor Valley, Antarctica}, journal = {Geological Society of America Bulletin}, volume = {119}, year = {2007}, month = {01/2007}, pages = {548-555}, keywords = {LTER-MCM, Climate Response}, doi = {10.1130/B25913.1}, url = {http://gsabulletin.gsapubs.org/content/119/5-6/548.short}, author = {Harris, K and Anne E. Carey and Kathleen A. Welch and W. Berry Lyons and Andrew G Fountain} } @article {1248, title = {The southernmost worm, Scottnema lindsayae (Nematoda): diversity, dispersal and ecological stability.}, journal = {Polar Biology}, volume = {30}, year = {2007}, pages = {809-815}, keywords = {LTER-MCM}, doi = {LTER}, author = {Byron Adams and Diana H. Wall and Gozel, U and Dillman, A and Chaston, J and Hogg, I} } @mastersthesis {1249, title = {Spatial and Temporal Active Layer Thermal Dynamics from Temperature Time Series Analysis: Case Studies from Lake Fryxell, McMurdo Dry Valleys, Antarctica.}, volume = {M.S.}, year = {2007}, school = {Colorado School of Mines}, type = {masters}, keywords = {LTER-MCM}, doi = {LTER}, author = {Ikard, S} } @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} } @article {1283, title = {Salt tolerance and survival thresholds for two species of Antarctic soil nematodes}, journal = {Polar Biology}, volume = {29}, year = {2006}, pages = {643-651}, keywords = {LTER-MCM}, doi = {LTER}, author = {Johnson N. Nkem and Ross A. Virginia and John E. Barrett and Diana H. Wall and Li, G} } @article {1284, title = {Simulating energy flow through a pelagic food web in Lake Fryxell, Antarctica}, journal = {Ecological Modelling}, volume = {192}, year = {2006}, pages = {457-472}, keywords = {LTER-MCM}, doi = {LTER}, author = {McKenna, K and Daryl L. Moorhead and Emily C. Roberts and Johanna Laybourn-Parry} } @article {1274, title = {Soil carbon turnover model for the McMurdo Dry Valleys, Antarctica}, journal = {Soil Biology and Biochemistry}, volume = {38}, year = {2006}, pages = {3065-3082}, keywords = {LTER-MCM}, doi = {LTER}, author = {John E. Barrett and Ross A. Virginia and Andrew N. Parsons and Diana H. Wall} } @mastersthesis {1285, title = {Soil nitrogen cycling in cold desert (McMurdo Dry Valleys) and hot desert ecosystems}, volume = {M.S.}, year = {2006}, school = {Dartmouth College}, type = {masters}, keywords = {LTER-MCM}, doi = {LTER}, author = {Stucker, A} } @article {1275, title = {Spatial and temporal active layer dynamics along three glacial meltwater streams in the McMurdo Dry Valleys, Antarctica}, journal = {Arctic Antarctic and Alpine Research}, volume = {38}, year = {2006}, pages = {42-53}, keywords = {LTER-MCM}, doi = {LTER}, author = {Peter A. Conovitz and Lee H. MacDonald and Diane M. McKnight} } @thesis {1276, title = {Spatial Patterns of Bacterial Diversity in Cold Desert Riparian Zones.}, volume = {B.S.}, year = {2006}, school = {University of New Mexico}, type = {bachelors}, keywords = {LTER-MCM}, doi = {LTER}, author = {Bobb, M} } @article {1258, title = {A stable isotopic investigation of a polar desert hydrologic system, McMurdo Dry Valleys, Antarctica}, journal = {Arctic, Antarctic, and Alpine Research}, volume = {38}, year = {2006}, month = {02/2006}, pages = {60-71}, keywords = {LTER-MCM}, doi = {10.1657/1523-0430(2006)038[0060:ASIIOA]2.0.CO;2}, author = {Michael N. Gooseff and W. Berry Lyons and Diane M. McKnight and Bruce H. Vaughn and Andrew G Fountain and Carolyn Dowling} } @article {1277, title = {A synthesis of soil biodiversity and ecosystem functioning in Victoria Land, Antarctica}, journal = {Soil Biology and Biochemistry}, volume = {38}, year = {2006}, pages = {3001-3002}, keywords = {LTER-MCM}, doi = {LTER}, author = {Diana H. Wall and Byron Adams and John E. Barrett and D. W. Hopkins} } @article {1288, title = {Sensitivity analysis of conservative and reactive stream transient storage models applied to field data from multiple-reach experiments}, journal = {Advances in Water Resources}, volume = {28}, year = {2005}, month = {05/2005}, pages = {479-492}, keywords = {LTER-MCM}, doi = {10.1016/j.advwatres.2004.11.012}, author = {Michael N. Gooseff and Kenneth E. Bencala and Durelle T. Scott and Robert L. Runkel and Diane M. McKnight} } @inbook {1309, title = {Soils, freshwater and marine sediments: the need for integrative landscape science}, booktitle = {Marine Ecology Progress Series}, series = {Theme Section: Bridging the Gap between Aquatic and Terrestrial Ecology.}, volume = {304}, year = {2005}, pages = {302-307}, keywords = {LTER-MCM}, doi = {LTER}, author = {Diana H. Wall and Edward Ayres and Valerie Behan-Pelletier and Covich, A and P.V.R. Snelgrove}, editor = {H. Browman and K. I. Stergiou} } @article {1342, title = {Soil carbon dioxide flux from Antarctic Dry Valley soils}, journal = {Ecosystems}, volume = {7}, year = {2004}, pages = {286-295}, keywords = {LTER-MCM}, author = {Andrew N. Parsons and John E. Barrett and Diana H. Wall and Ross A. Virginia} } @thesis {1355, title = {Soil phosphorus dynamics in Taylor Valley, Antarctica}, volume = {B.S.}, year = {2004}, school = {Dartmouth College}, type = {bachelors}, keywords = {LTER-MCM}, doi = {LTER}, author = {D. Brad Bate} } @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} } @book {1344, title = {Sustaining Biodiversity and Ecosystem Services in Soil and Sediments.}, series = {Scientific Committee on Problems of the Environment (SCOPE) Series Vol. 64}, year = {2004}, keywords = {LTER-MCM}, doi = {LTER}, author = {Diana H. Wall}, editor = {Diana H. Wall} } @mastersthesis {1367, title = {Spatial and temporal variations of phytoplankton populations in Lake Bonney}, volume = {M.S.}, year = {2003}, school = {Montana State University}, type = {masters}, keywords = {LTER-MCM}, doi = {LTER}, author = {Turish, N} } @article {1368, title = {Strontium isotopic signatures of the streams and lakes of Taylor Valley, southern Victoria Land, Antarctica: chemical weathering in a polar climate}, journal = {Aquatic Geochemistry}, volume = {8}, year = {2003}, pages = {875-895}, keywords = {LTER-MCM}, author = {W. Berry Lyons and C. A. Nezat and Benson, L and Bullen, T and Graham, E and Kidd, J and Kathleen A. Welch and Thomas, J} } @article {1369, title = {Surface glaciochemistry of Taylor Valley, southern Victoria Land, Antarctica and its relationship to stream chemistry.}, journal = {Hydrological Processes}, volume = {17}, year = {2003}, pages = {115-130}, keywords = {LTER-MCM}, author = {W. Berry Lyons and Kathleen A. Welch and Andrew G Fountain and Gayle L. Dana and Bruce H. Vaughn and Diane M. McKnight} } @article {1383, title = {Satellite-Derived Indices of Stream Discharge in Taylor Valley,Antarctica.}, journal = {Hydrological Processes}, volume = {16}, year = {2002}, pages = {1603-1616}, keywords = {LTER-MCM}, author = {Gayle L. Dana and Davis, R and Andrew G Fountain and Robert A. Wharton Jr.} } @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 {1395, title = {Survival mechanisms in Antarctic lakes}, journal = {Philosophical Transactions of the Royal Society B}, volume = {357}, year = {2002}, pages = {863-869}, keywords = {LTER-MCM}, author = {Johanna Laybourn-Parry} } @article {1384, title = {Synthetic aperture radar detection of the snowline on Commonwealth and Howard Glaciers, Taylor Valley, Antarctica}, journal = {Annals of Glaciology}, volume = {34}, year = {2002}, pages = {177-183}, keywords = {LTER-MCM}, author = {Bardel, P and Andrew G Fountain and Hall, D and Kwok, R} } @mastersthesis {1413, title = {Sensitivity of carbon dynamics to changing light availability of benthic microbial mats in Lake Hoare, Antarctica}, volume = {M.S.}, year = {2001}, school = {University of Toledo}, type = {masters}, keywords = {LTER-MCM}, doi = {LTER}, author = {Schmeling, J} } @inbook {1407, title = {Soil Biodiversity}, booktitle = {Global Biodiversity in a Changing Environment}, year = {2001}, pages = {47-82}, publisher = {Springer Verlag}, organization = {Springer Verlag}, address = {New York}, keywords = {LTER-MCM}, author = {Diana H. Wall and Gina A. Adams and Andrew N. Parsons}, editor = {F. S. Chapin and Osvaldo E. Sala and E. Huber-Sannwald} } @article {1408, title = {Spectrofluorometric characterization of aquatic fulvic acid for determination of precursor organic material and general structural properties.}, journal = {Limnology and Oceanography}, volume = {46}, year = {2001}, pages = {38-48}, keywords = {LTER-MCM}, author = {Diane M. McKnight and Elizabeth W. Boyer and Paul K. Westerhoff and Peter T. Doran and Thomas Kulbe and Dale T. Andersen} } @mastersthesis {1420, title = {Synthetic aperture radar imagery of polar glaciers}, volume = {M.S.}, year = {2001}, school = {Portland State University}, type = {masters}, keywords = {LTER-MCM}, doi = {LTER}, author = {Bardel, P} } @inbook {1438, title = {Soil Biodiversity and Ecosystem Functioning}, booktitle = {Biological Resource Management. Connecting Science and Policy}, year = {2000}, pages = {283-290}, publisher = {Springer}, organization = {Springer}, address = {Heidelberg}, keywords = {LTER-MCM}, author = {Diana H. Wall and J.M. Lynch}, editor = {E. Balazs and E. Galante and J.M. Lynch and J.S. Schepers} } @inbook {1444, title = {Soil Conservation}, booktitle = {Encyclopedia of Biodiversity}, volume = {5}, year = {2000}, pages = {315-326}, publisher = {Academic Press}, organization = {Academic Press}, keywords = {LTER-MCM}, author = {Porazinska, D and Diana H. Wall}, editor = {S. Levin} } @article {1421, title = {Stratification and dynamics of microbial loop communities in Lake Fryxell, Antarctica}, journal = {Freshwater Biology}, volume = {44}, year = {2000}, month = {12/2001}, pages = {649-661}, type = {Journal}, keywords = {LTER-MCM, Biggie, protozoa}, doi = {10.1046/j.1365-2427.2000.00612.x}, url = {http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2427.2000.00612.x/abstract}, author = {Emily C. Roberts and Johanna Laybourn-Parry and Diane M. McKnight and Novarino, G} } @article {1470, title = {Seasonal change in the optical properties of the permanent ice cover on Lake Bonney, Antarctica: Consequences for lake productivity and phytoplankton dynamics}, journal = {Limnology and Oceanography}, volume = {44}, year = {1999}, pages = {447-454}, keywords = {LTER-MCM}, author = {Christian H. Fritsen and John C. Priscu} } @inbook {1471, title = {Soil Biodiversity: life in soil}, booktitle = {The Living Planet in Crisis}, year = {1999}, pages = {124-128}, publisher = {Columbia University Press}, organization = {Columbia University Press}, keywords = {LTER-MCM}, doi = {LTER}, author = {Diana H. Wall}, editor = {J. Cracraft and F. Griffo} } @inbook {1472, title = {Soil invertebrates}, booktitle = {Standard Soil Methods for Long Term Ecological Research}, year = {1999}, pages = {349-377}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {New York}, keywords = {LTER-MCM}, doi = {LTER}, author = {David C. Coleman and J.M. Blair and Elliot, E and Diana H. Wall} } @article {1480, title = {Spatial and climatic variations and its control on glacier equilibrium line altitude in Taylor Valley, Antarctica}, journal = {Global and Planetary Change}, volume = {22}, year = {1999}, pages = {1-10}, keywords = {LTER-MCM} } @inbook {1540, title = {Science and Environmental Management in the McMurdo Dry Valleys, Southern Victoria Land, Antarctica}, booktitle = {Ecosystem Processes in a Polar Desert: The McMurdo Dry Valleys, Antarctica}, series = {Antarctic Research Series}, volume = {72}, year = {1998}, pages = {337-350}, keywords = {LTER-MCM}, author = {Harris, Colin M.} } @article {1529, title = {Soil Biodiversity and Community Structure in the McMurdo Dry Valleys, Antarctica, in Ecosystem Processes in a Polar Desert: The McMurdo Dry Valleys, Antarctica}, journal = {Antarctic Research Series}, volume = {72}, year = {1998}, pages = {323-335}, keywords = {LTER-MCM}, author = {Diana W. Freckman and Ross A. Virginia} } @inbook {1530, title = {The Soil Environment of the McMurdo Dry Valleys, Antarctica}, booktitle = {Ecosystem Processes in a Polar Desert: The McMurdo Dry Valleys, Antarctica}, series = {Antarctic Research Series}, volume = {72}, year = {1998}, pages = {297-322}, keywords = {LTER-MCM}, author = {Iain B. Campbell and Graeme G.C. Claridge and David I. Campbell and Megan R. Balks} } @inbook {1531, title = {Solar Radiation in the McMurdo Dry Valleys, Antarctica}, booktitle = {Ecosystem Processes in a Polar Desert: The McMurdo Dry Valleys, Antarctica}, series = {Antarctic Research Series}, volume = {72}, year = {1998}, pages = {39-64}, keywords = {LTER-MCM}, author = {Gayle L. Dana and Robert A. Wharton Jr. and R. Dubayah} } @mastersthesis {1541, title = {Spatial-temporal patterns of primary production in phytoplankton communities of Taylor Valley lakes, Antartica: A modelling synthesis}, volume = {M.S.}, year = {1998}, school = {Texas Tech University}, type = {masters}, keywords = {LTER-MCM}, doi = {LTER}, author = {Davis, W} } @article {1532, title = {Structure and composition of the photochemical apparatus of the Antarctic green alga Chlamydomonas subcaudata}, journal = {Photosynthesis Research - Regular Paper}, volume = {56}, year = {1998}, pages = {303-314}, keywords = {LTER-MCM}, author = {Morgan, Rachael M. and Alexander G. Ivanov and John C. Priscu and Denis P. Maxwell and Norman P.A. Huner} } @article {1533, title = {Surface energy balance and meltwater production for a Dry Valley glacier, Taylor Valley, Antarctica}, journal = {Annals of Glaciology}, volume = {27}, year = {1998}, pages = {603-609}, keywords = {LTER-MCM}, author = {Karen J. Lewis and Andrew G Fountain and Gayle L. Dana} } @inbook {1561, title = {Satellite-derived surface temperatures in the McMurdo Dry Valleys, Antarctica}, booktitle = {IRS {\textquoteright}96 Current Problems in Atmospheric Radiation}, year = {1997}, pages = {530-533}, publisher = {Deepak}, organization = {Deepak}, keywords = {LTER-MCM}, author = {Gayle L. Dana and M.A. Wetzel and Robert A. Wharton Jr.} } @inbook {1563, title = {Sources and sinks of nutrients in a polar desert stream, the Onyx River, Antarctica}, booktitle = {Ecosystem Processes in Antarctic Ice-free Landscapes}, year = {1997}, pages = {155-170}, publisher = {Balkema Press}, organization = {Balkema Press}, address = {Rotterdam}, keywords = {LTER-MCM}, author = {Clive Howard-Williams and Ian Hawes and Anne-Maree Schwarz and Julie A. Hall} } @inbook {1564, title = {Species composition and primary production of algal communities in Dry Valley streams in Antarctica: Examination of the functional role of biodiversity}, booktitle = {Ecosystem Processes in Antarctic Ice-free Landscapes}, year = {1997}, pages = {171-179}, publisher = {Balkema Press, Rotterdam}, organization = {Balkema Press, Rotterdam}, keywords = {LTER-MCM}, author = {Dev K. Niyogi and Cathy M. Tate and Diane M. McKnight and John H. Duff and Alexander S. Alger} } @inbook {1581, title = {Soil invertebrates as indicators of soil quality}, booktitle = {Methods for assessing soil quality}, year = {1996}, publisher = {Soil Science Society of America}, organization = {Soil Science Society of America}, address = {Madison, WI}, keywords = {LTER-MCM}, author = {J.M. Blair and Patrick J. Bohlen and Diana W. Freckman}, editor = {J. W. Doran and A.J. Jones} } @mastersthesis {1610, title = {Soil nematode distribution and genetic diversity in the Dry Valleys of Antarctica}, volume = {M.S.}, year = {1996}, school = {Colorado State University}, type = {masters}, address = {Fort Collins, CO}, keywords = {LTER-MCM}, author = {Courtright, Ericha M and Diana H. Wall} } @article {1582, title = {Soil spatial variation along a toposequence in Taylor Valley, Antarctica}, journal = {Bulletin of the Ecological Society of America Supplement}, volume = {77}, year = {1996}, pages = {197}, keywords = {LTER-MCM}, author = {Mengchi Ho and Ross A. Virginia and Diana W. Freckman} } @article {1583, title = {Sources and distribution of abundance of organic matter in the Dry Valley soils of southern Victoria Land, Antarctica}, journal = {Bulletin of the Ecological Society of America Supplement}, volume = {77}, year = {1996}, pages = {56}, keywords = {LTER-MCM}, author = {Melody J. Brown and Ross A. Virginia and C. Page Chamberlain} } @mastersthesis {1586, title = {Surface energy balance and meltwater production for a dry valley glacier, Taylor Valley, Antarctica}, volume = {M.S.}, year = {1996}, school = {University of Colorado}, type = {masters}, keywords = {LTER-MCM}, doi = {LTER}, author = {Karen J. Lewis} } @article {1603, title = {Soil chemistry along a glacial chronosequence on Andrews Ridge, Taylor Valley}, journal = {Antarctic Journal of the U.S.}, volume = {30}, year = {1995}, pages = {310-311}, keywords = {LTER-MCM}, author = {Mengchi Ho and Ross A. Virginia and Powers, Laura E. and Diana W. Freckman} } @article {1604, title = {Some metamorphic processes in the lake ice of the McMurdo Dry Valleys}, journal = {Antarctic Journal of the U.S.}, volume = {30}, year = {1995}, pages = {307-309}, keywords = {LTER-MCM}, author = {Edward E. Adams and John C. Priscu and Atsushi Sato} } @article {1605, title = {Spatial Distribution of Nematodes in Polar Desert Soils of Antarctica}, journal = {Polar Biology}, volume = {15}, year = {1995}, pages = {325-333}, keywords = {LTER-MCM}, author = {Powers, Laura E. and Diana W. Freckman and Ross A. Virginia} } @article {1606, title = {Streamflow, water-temperature, and specific-conductance data for selected streams draining into Lake Fryxell, Lower Taylor Valley, Victoria Land, Antarctica, 1990-92}, journal = {U.S. Geological Survey. Open-File Report 94-545}, year = {1995}, keywords = {LTER-MCM}, author = {Paul Von Guerard and Diane M. McKnight and Richard A. Harnish and J. W. Gartner and Edmund D. Andrews} } @inbook {1628, title = {Stromatolite mats in Antarctic lakes}, booktitle = {Phanerozoic Stromatolites II}, year = {1994}, publisher = {Kluwer, Netherlands}, organization = {Kluwer, Netherlands}, keywords = {LTER-MCM}, author = {Robert A. Wharton Jr.} } @article {1629, title = {Survival of Scottnema lindsayae under extreme osmotic conditions}, journal = {Society of Nematologists}, year = {1994}, keywords = {LTER-MCM}, author = {Powers, Laura E. and Diana W. Freckman and Ross A. Virginia} } @article {1645, title = {Stable isotopic biogeochemistry of carbon and nitrogen in a perennially ice-covered Antarctic lake}, journal = {Chemical Geology}, volume = {107}, year = {1993}, pages = {159-172}, keywords = {LTER-MCM}, author = {Robert A. Wharton Jr. and W. Berry Lyons and D.J. Des Marais} } @article {1652, title = {Spectral Irradiance and Bio-Optical Properties in Perennially Ice-Covered Lakes of the Dry Valleys (McMurdo Sound, Antarctica)}, journal = {Antarctic Research Series}, volume = {57}, year = {1992}, pages = {1-14}, keywords = {LTER-MCM}, author = {Michael P. Lizotte and John C. Priscu} }