<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Lee F. Stanish</style></author><author><style face="normal" font="default" size="100%">Tyler J. Kohler</style></author><author><style face="normal" font="default" size="100%">Darling, Joshua P.</style></author><author><style face="normal" font="default" size="100%">Diane M. McKnight</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Drifting along: Using diatoms to track the contribution of microbial mats to particulate organic matter transport in a glacial meltwater stream in the McMurdo Dry Valleys, Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">Frontiers in Microbiology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">cyanobacteria</style></keyword><keyword><style  face="normal" font="default" size="100%">diatom</style></keyword><keyword><style  face="normal" font="default" size="100%">flow regime</style></keyword><keyword><style  face="normal" font="default" size="100%">hydrology</style></keyword><keyword><style  face="normal" font="default" size="100%">microbial mat</style></keyword><keyword><style  face="normal" font="default" size="100%">Nostoc</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2024</style></year><pub-dates><date><style  face="normal" font="default" size="100%">05/2024</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1352666/full</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">15</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Flow pulses mobilize particulate organic matter (POM) in streams from the surrounding landscape and streambed. This POM serves as a source of energy and nutrients, as well as a means for organismal dispersal, to downstream communities. In the barren terrestrial landscape of the McMurdo Dry Valleys (MDV) of Antarctica, benthic microbial mats occupying different in-stream habitat types are the dominant POM source in the many glacier-fed streams. Many of these streams experience daily flow peaks that mobilize POM, and diatoms recovered from underlying stream sediments suggest that mat-derived diatoms in the POM are retained there through hyporheic exchange. Yet, &amp;lsquo;how much&amp;rsquo; and &amp;lsquo;when&amp;rsquo; different in-stream habitat types contribute to POM diatom assemblages is unknown. To quantify the contribution of different in-stream habitat types to POM diatom assemblages, we collected time-integrated POM samples over four diel experiments, which spanned a gradient of flow conditions over three summers. Diatoms from POM samples were identified, quantified, and compared with dominant habitat types (i.e., benthic &amp;lsquo;orange&amp;rsquo; mats, marginal &amp;lsquo;black&amp;rsquo; mats, and bare sediments). Like bulk POM, diatom cell concentrations followed a clockwise hysteresis pattern with stream discharge over the daily flow cycles, indicating supply limitation. Diatom community analyses showed that different habitat types harbor distinct diatom communities, and mixing models revealed that a substantial proportion of POM diatoms originated from bare sediments during baseflow conditions. Meanwhile, orange and black mats contribute diatoms to POM primarily during daily flow peaks when both cell concentrations and discharge are highest, making mats the most important contributors to POM diatom assemblages at high flows. These observations may help explain the presence of mat-derived diatoms in hyporheic sediments. Our results thus indicate a varying importance of different in-stream habitats to POM generation and export on daily to seasonal timescales, with implications for biogeochemical cycling and the local diatom metacommunity.&lt;/p&gt;</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Salvatore, Mark R.</style></author><author><style face="normal" font="default" size="100%">Barrett, John E.</style></author><author><style face="normal" font="default" size="100%">Fackrell, Laura E.</style></author><author><style face="normal" font="default" size="100%">Sokol, Eric R.</style></author><author><style face="normal" font="default" size="100%">Levy, Joseph S.</style></author><author><style face="normal" font="default" size="100%">Kuentz, Lily C.</style></author><author><style face="normal" font="default" size="100%">Gooseff, Michael N.</style></author><author><style face="normal" font="default" size="100%">Adams, Byron J.</style></author><author><style face="normal" font="default" size="100%">Power, Sarah N.</style></author><author><style face="normal" font="default" size="100%">Knightly, J. Paul</style></author><author><style face="normal" font="default" size="100%">Matul, Haley M.</style></author><author><style face="normal" font="default" size="100%">Szutu, Brian</style></author><author><style face="normal" font="default" size="100%">Doran, Peter T.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">The distribution of surface soil moisture over space and time in eastern Taylor Valley, Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">Remote Sensing</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Dry valleys</style></keyword><keyword><style  face="normal" font="default" size="100%">ecology</style></keyword><keyword><style  face="normal" font="default" size="100%">hydrology</style></keyword><keyword><style  face="normal" font="default" size="100%">remote sensing</style></keyword><keyword><style  face="normal" font="default" size="100%">soil moisture</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2023</style></year><pub-dates><date><style  face="normal" font="default" size="100%">06/2023</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.mdpi.com/2072-4292/15/12/3170</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">15</style></volume><pages><style face="normal" font="default" size="100%">3170</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Available soil moisture is thought to be the limiting factor for most ecosystem processes in the cold polar desert of the McMurdo Dry Valleys (MDVs) of Antarctica. Previous studies have shown that microfauna throughout the MDVs are capable of biological activity when sufficient soil moisture is available (~2&amp;ndash;10% gravimetric water content), but few studies have attempted to quantify the distribution, abundance, and frequency of soil moisture on scales beyond that of traditional field work or local field investigations. In this study, we present our work to quantify the soil moisture content of soils throughout the Fryxell basin using multispectral satellite remote sensing techniques. Our efforts demonstrate that ecologically relevant abundances of liquid water are common across the landscape throughout the austral summer. On average, the Fryxell basin of Taylor Valley is modeled as containing 1.5 &amp;plusmn; 0.5% gravimetric water content (GWC) across its non-fluvial landscape with ~23% of the landscape experiencing an average GWC &amp;gt; 2% throughout the study period, which is the observed limit of soil nematode activity. These results indicate that liquid water in the soils of the MDVs may be more abundant than previously thought, and that the distribution and availability of liquid water is dependent on both soil properties and the distribution of water sources. These results can also help to identify ecological hotspots in the harsh polar Antarctic environment and serve as a baseline for detecting future changes in the soil hydrological regime.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">12</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Joseph S. Levy</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Episodic basin-scale soil moisture anomalies associated with high relative humidity events in the McMurdo Dry Valleys, Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">Antarctic Science</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">deliquescence</style></keyword><keyword><style  face="normal" font="default" size="100%">hydrology</style></keyword><keyword><style  face="normal" font="default" size="100%">microclimate</style></keyword><keyword><style  face="normal" font="default" size="100%">micrometeorology</style></keyword><keyword><style  face="normal" font="default" size="100%">pedology</style></keyword><keyword><style  face="normal" font="default" size="100%">remote sensing</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2021</style></year><pub-dates><date><style  face="normal" font="default" size="100%">08/2021</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.cambridge.org/core/product/identifier/S0954102021000341/type/journal_article</style></url></web-urls></urls><pages><style face="normal" font="default" size="100%">1-15</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Outside of hydrologically wetted active layer soils and humidity-sensitive soil brines, low soil moisture is a limiting factor controlling biogeochemical processes in the McMurdo Dry Valleys. But anecdotal field observations suggest that episodic wetting and darkening of surface soils in the absence of snowmelt occurs during high humidity conditions. Here, I analyse long-term meteorological station data to determine whether soil-darkening episodes are present in the instrumental record and whether they are, in fact, correlated with relative humidity. A strong linear correlation is found between relative humidity and soil reflectance at the Lake Bonney long-term autonomous weather station. Soil reflectance is found to decrease annually by a median of 27.7% in response to high humidity conditions. This magnitude of darkening is consistent with soil moisture rising from typical background values of &amp;lt; 0.5 wt.% to 2&amp;ndash;3 wt.%, suggesting that regional atmospheric processes may result in widespread soil moisture generation in otherwise dry surface soils. Temperature and relative humidity conditions under which darkening is observed occur for hundreds of hours per year, but are dominated by episodes occurring between midnight and 07h00 local time, suggesting that wetting events may be common, but are not widely observed during typical diel science operations.&lt;/p&gt;</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Salvatore, Mark R.</style></author><author><style face="normal" font="default" size="100%">Borges, Schuyler R.</style></author><author><style face="normal" font="default" size="100%">John E. Barrett</style></author><author><style face="normal" font="default" size="100%">Eric R. Sokol</style></author><author><style face="normal" font="default" size="100%">Lee F. Stanish</style></author><author><style face="normal" font="default" size="100%">Power, Sarah N.</style></author><author><style face="normal" font="default" size="100%">Morin, Paul</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Remote characterization of photosynthetic communities in the Fryxell basin of Taylor Valley, Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">Antarctic Science</style></secondary-title><short-title><style face="normal" font="default" size="100%">Antarctic Science</style></short-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">ecology</style></keyword><keyword><style  face="normal" font="default" size="100%">hydrology</style></keyword><keyword><style  face="normal" font="default" size="100%">McMurdo Dry Valleys</style></keyword><keyword><style  face="normal" font="default" size="100%">microbiology</style></keyword><keyword><style  face="normal" font="default" size="100%">remote sensing</style></keyword><keyword><style  face="normal" font="default" size="100%">spectroscopy</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2020</style></year><pub-dates><date><style  face="normal" font="default" size="100%">03/2020</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.cambridge.org/core/journals/antarctic-science/article/remote-characterization-of-photosynthetic-communities-in-the-fryxell-basin-of-taylor-valley-antarctica/8576F6BB1BCFDCA8409F5EA96CA00C6F</style></url></web-urls></urls><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;We investigate the spatial distribution, spectral properties and temporal variability of primary producers (e.g. communities of microbial mats and mosses) throughout the Fryxell basin of Taylor Valley, Antarctica, using high-resolution multispectral remote-sensing data. Our results suggest that photosynthetic communities can be readily detected throughout the Fryxell basin based on their unique near-infrared spectral signatures. Observed intra- and inter-annual variability in spectral signatures are consistent with short-term variations in mat distribution, hydration and photosynthetic activity. Spectral unmixing is also implemented in order to estimate mat abundance, with the most densely vegetated regions observed from orbit correlating spatially with some of the most productive regions of the Fryxell basin. Our work establishes remote sensing as a valuable tool in the study of these ecological communities in the McMurdo Dry Valleys and demonstrates how future scientific investigations and the management of specially protected areas could benefit from these tools and techniques.&lt;/p&gt;</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>32</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Mass, Alex Q.</style></author><author><style face="normal" font="default" size="100%">Diane M. McKnight</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Biogeochemistry, contaminant transport, and atmospheric exchange in glacial cryoconite meltwater of the McMurdo Dry Valleys, Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">Department of Civil, Environmental, and Architectural Engineering</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Antarctica</style></keyword><keyword><style  face="normal" font="default" size="100%">applied sciences</style></keyword><keyword><style  face="normal" font="default" size="100%">contaminant transport</style></keyword><keyword><style  face="normal" font="default" size="100%">cryoconite</style></keyword><keyword><style  face="normal" font="default" size="100%">earth sciences</style></keyword><keyword><style  face="normal" font="default" size="100%">glacier</style></keyword><keyword><style  face="normal" font="default" size="100%">hydrology</style></keyword><keyword><style  face="normal" font="default" size="100%">melt</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2018</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2018</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://search.proquest.com/docview/2048314678</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">University of Colorado</style></publisher><pub-location><style face="normal" font="default" size="100%">Boulder, CO</style></pub-location><volume><style face="normal" font="default" size="100%">Ph.D.</style></volume><pages><style face="normal" font="default" size="100%">245</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Polar regions serve as a global sink for many forms of semi-volatile pollution emitted from low- or midlatitudes of the populated world. This study examined the longrange atmospheric transport, fate, and phase partitioning of semi-volatile organic contaminants from air masses into meltwater and aeolian sediment on six glaciers in the McMurdo Dry Valleys of Antarctica. A novel low-cost, field-portable instrument was developed for the in-situ solid-phase extraction of trace contaminants in extreme environmental conditions without access to electricity or traditional laboratory facilities. Beyond polar research, this equipment is applicable for rapid field extraction and stabilization of samples assessing air and water quality after natural disasters. This is the first published study to identify the presence of anthropogenic perfluorinated compounds in the Transantarctic Mountain region and indicates a longer range of poleward contaminant transport than prior estimates in the Southern Hemisphere. Additional research examined the biochemistry and climatic variability of open and sealed cryoconite holes on glacial surfaces throughout the initial melt, equilibrium, and refreezing periods in 2013&amp;ndash;2015. High solute concentrations relative to glacial ice indicate that the pools can remain isolated from hydrologic connectivity for more than a decade. Microbial carbon cycling in pools enclosed by ice led to atmospheric disequilibrium and extreme pH. Analysis of unique air, liquid, and ice stratification in cryoconite holes revealed vertical patterns representing a highly accurate, multi-year record of past weather conditions sensitive enough to identify individual dates. This research identifies fluctuations in atmospheric contaminant transport, specific timeframes for deposition events, and may be used in back-trajectory models to help identify the source and variability of semi-volatile emissions in the Southern hemisphere.&lt;/p&gt;</style></abstract><work-type><style face="normal" font="default" size="100%">doctoral</style></work-type></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>32</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Bernzott, Emily D.</style></author><author><style face="normal" font="default" size="100%">Michael N. Gooseff</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Modeling nitrate concentrations in an Antarctic glacial meltwater stream under fluctuating hydrologic conditions and nitrate inputs</style></title><secondary-title><style face="normal" font="default" size="100%">Department of Civil &amp; Environmental Engineering</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">hydrology</style></keyword><keyword><style  face="normal" font="default" size="100%">hyporheic zone</style></keyword><keyword><style  face="normal" font="default" size="100%">nitrate</style></keyword><keyword><style  face="normal" font="default" size="100%">nutrients</style></keyword><keyword><style  face="normal" font="default" size="100%">primary productivity</style></keyword><keyword><style  face="normal" font="default" size="100%">stream</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2012</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://etda.libraries.psu.edu/catalog/15316</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">Pennsylvania State University</style></publisher><volume><style face="normal" font="default" size="100%">M.S.</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The McMurdo Dry Valleys comprise a unique polar desert ecosystem in Victoria Land, Antarctica. The hydrologic system in the Dry Valleys is often characterized as being simplified compared to temperate watersheds, due to the ability to identify physical boundaries and nutrient sources and sinks. We seek to characterize the evolution of streamflow, solutes, and nutrients along a glacial meltwater stream in the McMurdo Dry Valleys, and to understand the role of different sources and sinks under varying hydrologic conditions. The study presented here includes streamflow routing, solute modeling, and nitrate concentration modeling in Von Guerard stream, a stream with abundant algal coverage in the McMurdo Dry Valleys region of Antarctica. The streamflow model is a solution to the kinematic wave routing problem. Solute modeling addresses advection, dispersion, as well as hyporheic zone inputs, which are controlled by weathering and hyporheic exchange. Lastly, the nitrate model builds on the solute model with the addition of a gross primary production (GPP) component. Results indicate that the hyporheic source of nitrate is controlling due to rapid exchange with the main channel. GPP impacts are small due to light-saturated conditions for a majority of the season, but provide a consistent sink for nitrate. The role of advective and dispersive transport is highly dependent on flow conditions, with advective transport controlling at high flows and dispersive controlling at low flows.&lt;/p&gt;</style></abstract><work-type><style face="normal" font="default" size="100%">masters</style></work-type></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>32</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Weaver, Mitchell R.</style></author><author><style face="normal" font="default" size="100%">Michael N. Gooseff</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Hydrologic controls of nutrient fluxes in glacial meltwater streams at inter-annual, seasonal, and daily timescales in the McMurdo Dry Valleys, Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">Department of Civil &amp; Environmental Engineering</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Antarctica</style></keyword><keyword><style  face="normal" font="default" size="100%">biogeochemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">chemical weathering</style></keyword><keyword><style  face="normal" font="default" size="100%">discharge</style></keyword><keyword><style  face="normal" font="default" size="100%">electrical conductivity</style></keyword><keyword><style  face="normal" font="default" size="100%">glacial melt</style></keyword><keyword><style  face="normal" font="default" size="100%">glaciers</style></keyword><keyword><style  face="normal" font="default" size="100%">hydrology</style></keyword><keyword><style  face="normal" font="default" size="100%">hyporheic</style></keyword><keyword><style  face="normal" font="default" size="100%">MCM LTER</style></keyword><keyword><style  face="normal" font="default" size="100%">McMurdo Dry Valleys</style></keyword><keyword><style  face="normal" font="default" size="100%">nutrient fluxes</style></keyword><keyword><style  face="normal" font="default" size="100%">nutrients</style></keyword><keyword><style  face="normal" font="default" size="100%">polar desert</style></keyword><keyword><style  face="normal" font="default" size="100%">solute chemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">stream chemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">streamflow</style></keyword><keyword><style  face="normal" font="default" size="100%">water chemistry</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2011</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://etda.libraries.psu.edu/catalog/11568</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">Pennsylvania State University</style></publisher><volume><style face="normal" font="default" size="100%">M.S.</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;In the McMurdo Dry Valleys of Antarctica, glaciers are hydrologically linked to closed-basin lakes at the valley floor by glacial meltwater streams. Streams flow through porous, well-defined channels with extensive chemically active hyporheic zones. Temporally varying dynamics of meltwater generation and sub-stream thaw depth are thought to control the potential for the hyporheic zone and benthic communities to influence transport of nutrients and dissolved ions downstream. Using the McMurdo LTER database, patterns in stream discharge, electrical conductivity (both with 15-minute sampling intervals), and solute chemistry (weekly sampling intervals) were examined on eight MDV streams from 1990-2008. Discharge and electrical conductivity values were highly variable among streams. Discharge values were highly dependent upon glacial source area, but meteorological and topographical complexities create large variability at all time scales. The longer streams were found to have much higher electrical conductivity values than the shorter streams, suggesting that there are more opportunities for hyporheic weathering reactions along longer stream reaches. Weekly sampled water solutes from each stream&amp;#39;s entire record were plotted against the discharge recorded at the time when the sample was taken. Silicate concentrations displayed a decreasing logarithmic relationship, while nutrient concentrations had no apparent relationship. This suggests that with the exception to bioreactive solutes, the majority of hyporheic interactions could possibly be characterized by electrical conductivity and discharge. To attain information on in-stream nutrient dynamics and nutrient fluxes, glacial source water at the upper reach of Green Creek and stream outlet water at the lower reach of Green Creek were sampled hourly for two separate diel periods during the 2008-09 austral summer. Both dates were in late January under two distinct flow conditions (~0.5 L/s and ~10 L/s). Under low flow conditions, nutrient cycling was found to be uptake dominated. High flow conditions showed both uptake and regeneration with much higher nutrient loads, but as in the low flow conditions, no apparent temporal trends were found. Nutrient concentrations could not be predicted using the two parameters of discharge and electrical conductivity with in-stream nutrient dynamics likely too complicated at the sub-daily scale.&lt;/p&gt;</style></abstract><work-type><style face="normal" font="default" size="100%">masters</style></work-type></record></records></xml>