<?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%">Jill A. Mikucki</style></author><author><style face="normal" font="default" size="100%">Pearson, A</style></author><author><style face="normal" font="default" size="100%">Johnston, D</style></author><author><style face="normal" font="default" size="100%">Turchyn, A</style></author><author><style face="normal" font="default" size="100%">Farquhar, J</style></author><author><style face="normal" font="default" size="100%">Schrag, D</style></author><author><style face="normal" font="default" size="100%">Anbar, A</style></author><author><style face="normal" font="default" size="100%">John C. Priscu</style></author><author><style face="normal" font="default" size="100%">Lee, P</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">A Contemporary Microbially Maintained Subglacial Ferrous &quot;Ocean&quot;</style></title><secondary-title><style face="normal" font="default" size="100%">Science</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Biggie</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year><pub-dates><date><style  face="normal" font="default" size="100%">04/2009</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.sciencemag.org/content/324/5925/397.short</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">324</style></volume><pages><style face="normal" font="default" size="100%">397-400</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;&lt;span style=&quot;color: rgb(51, 51, 51); font-family: 'Lucida Grande', arial, helvetica, sans-serif; font-size: 12px; font-weight: bold; line-height: 18px; background-color: rgb(238, 238, 238);&quot;&gt;An active microbial assemblage cycles sulfur in a sulfate-rich, ancient marine brine beneath Taylor Glacier, an outlet glacier of the East Antarctic Ice Sheet, with Fe(III) serving as the terminal electron acceptor. Isotopic measurements of sulfate, water, carbonate, and ferrous iron and functional gene analyses of adenosine 5&amp;prime;-phosphosulfate reductase imply that a microbial consortium facilitates a catalytic sulfur cycle. These metabolic pathways result from a limited organic carbon supply because of the absence of contemporary photosynthesis, yielding a subglacial ferrous brine that is anoxic but not sulfidic. Coupled biogeochemical processes below the glacier enable subglacial microbes to grow in extended isolation, demonstrating how analogous organic-starved systems, such as Neoproterozoic oceans, accumulated Fe(II) despite the presence of an active sulfur cycle.&lt;/span&gt;&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">5925</style></issue><work-type><style face="normal" font="default" size="100%">Journal</style></work-type></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>5</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Hodson, A</style></author><author><style face="normal" font="default" size="100%">Alexandre M. Anesio</style></author><author><style face="normal" font="default" size="100%">Martyn Tranter</style></author><author><style face="normal" font="default" size="100%">Andrew G Fountain</style></author><author><style face="normal" font="default" size="100%">Osborn, M</style></author><author><style face="normal" font="default" size="100%">John C. Priscu</style></author><author><style face="normal" font="default" size="100%">Johanna Laybourn-Parry</style></author><author><style face="normal" font="default" size="100%">Sattler, B</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Glacial ecosystems</style></title><secondary-title><style face="normal" font="default" size="100%">Ecological Monographs</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Biggie</style></keyword><keyword><style  face="normal" font="default" size="100%">snow ecology</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1890/07-0187.1</style></url></web-urls></urls><edition><style face="normal" font="default" size="100%">1</style></edition><volume><style face="normal" font="default" size="100%">78</style></volume><pages><style face="normal" font="default" size="100%">41-67</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;div&gt;There is now compelling evidence that microbially mediated reactions impart a significant effect upon the dynamics, composition, and abundance of nutrients in glacial melt water. Consequently, we must now consider ice masses as ecosystem habitats in their own right and address their diversity, functional potential, and activity as part of alpine and polar environments. Although such research is already underway, its fragmentary nature provides little basis for developing modern concepts of glacier ecology. This paper therefore provides a much-needed framework for development by reviewing the physical, biogeochemical, and microbiological characteristics of microbial habitats that have been identified within glaciers and ice sheets. Two key glacial ecosystems emerge, one inhabiting the glacier surface (the supraglacial ecosystem) and one at the ice-bed interface (the subglacial ecosystem). The supraglacial ecosystem is characterized by a diverse consortium of microbes (usually bacteria, algae, phytoflagellates, fungi, viruses and occasional rotifers, tardigrades, and diatoms) within the snowpack, supraglacial streams, and melt pools (cryoconite holes). The subglacial system is dominated by aerobic/anaerobic bacteria and most probably viruses in basal ice/till mixtures and subglacial lakes. A third, so-called englacial ecosystem is also described, but it is demonstrated that conditions within glacier ice are sufficient to make metabolic activity and its impact upon nutrient dynamics negligible at the glacier scale.&lt;/div&gt;&lt;div&gt;&amp;nbsp;&lt;/div&gt;&lt;div&gt;Consideration of the surface and internal heat balances of the glacier show that all glacial ecosystems are sensitive to climate change, although at different timescales. Thus, while rapid, melt-driven habitat changes lead to melt-out, resuscitation, and redistribution of microorganisms in many supraglacial ecosystems, much slower climatic and glacial mass-balance processes effect such changes in the subglacial ecosystem. Paradoxically, it is shown that these forces have brought about net refreezing and the onset of cryostasis in the subglacial ecosystems of many Arctic glaciers subject to thinning in recent decades.&lt;/div&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%">John E. Barrett</style></author><author><style face="normal" font="default" size="100%">Ross A. Virginia</style></author><author><style face="normal" font="default" size="100%">W. Berry Lyons</style></author><author><style face="normal" font="default" size="100%">Diane M. McKnight</style></author><author><style face="normal" font="default" size="100%">John C. Priscu</style></author><author><style face="normal" font="default" size="100%">Andrew G Fountain</style></author><author><style face="normal" font="default" size="100%">Diana H. Wall</style></author><author><style face="normal" font="default" size="100%">Daryl L. Moorhead</style></author><author><style face="normal" font="default" size="100%">Peter T. Doran</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Biogeochemical stoichiometry of Antarctic Dry Valley ecosystems</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Geophysical Research</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Biggie</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2007</style></year><pub-dates><date><style  face="normal" font="default" size="100%">02/2007</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">112</style></volume><pages><style face="normal" font="default" size="100%">G01010+12</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;&lt;span style=&quot;color: rgb(51, 51, 51); font-family: 'Open Sans', Arial, Helvetica, 'Lucida Sans Unicode', sans-serif; font-size: 16px; line-height: 24px; background-color: rgb(249, 249, 249);&quot;&gt;Among aquatic and terrestrial landscapes of the McMurdo Dry Valleys, Antarctica, ecosystem stoichiometry ranges from values near the Redfield ratios for C:N:P to nutrient concentrations in proportions far above or below ratios necessary to support balanced microbial growth. This polar desert provides an opportunity to evaluate stoichiometric approaches to understand nutrient cycling in an ecosystem where biological diversity and activity are low, and controls over the movement and mass balances of nutrients operate over 10&amp;ndash;10&lt;/span&gt;&lt;span style=&quot;line-height: 0; top: -0.5em; padding-right: 1px; padding-left: 1px; outline: 0px; font-size: 0.688em; position: relative; color: rgb(51, 51, 51); font-family: 'Open Sans', Arial, Helvetica, 'Lucida Sans Unicode', sans-serif; background: 0px 0px rgb(249, 249, 249);&quot;&gt;6&lt;/span&gt;&lt;span style=&quot;color: rgb(51, 51, 51); font-family: 'Open Sans', Arial, Helvetica, 'Lucida Sans Unicode', sans-serif; font-size: 16px; line-height: 24px; background-color: rgb(249, 249, 249);&quot;&gt;&amp;nbsp;years. The simple organisms (microbial and metazoan) comprising dry valley foodwebs adhere to strict biochemical requirements in the composition of their biomass, and when activated by availability of liquid water, they influence the chemical composition of their environment according to these ratios. Nitrogen and phosphorus varied significantly in terrestrial and aquatic ecosystems occurring on landscape surfaces across a wide range of exposure ages, indicating strong influences of landscape development and geochemistry on nutrient availability. Biota control the elemental ratio of stream waters, while geochemical stoichiometry (e.g., weathering, atmospheric deposition) evidently limits the distribution of soil invertebrates. We present a conceptual model describing transformations across dry valley landscapes facilitated by exchanges of liquid water and biotic processing of dissolved nutrients. We conclude that contemporary ecosystem stoichiometry of Antarctic Dry Valley soils, glaciers, streams, and lakes results from a combination of extant biological processes superimposed on a legacy of landscape processes and previous climates.&lt;/span&gt;&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%">Rachael M. Morgan-Kiss</style></author><author><style face="normal" font="default" size="100%">John C. Priscu</style></author><author><style face="normal" font="default" size="100%">Pocock, T</style></author><author><style face="normal" font="default" size="100%">Gudynaite-Savitch, L</style></author><author><style face="normal" font="default" size="100%">Norman P.A. Huner</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Adaptation and acclimation of photosynthetic microorganisms to permanently cold environments</style></title><secondary-title><style face="normal" font="default" size="100%">Microbial and Molecular Biology Review</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Biggie</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2006</style></year><pub-dates><date><style  face="normal" font="default" size="100%">03/2006</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">70</style></volume><pages><style face="normal" font="default" size="100%">222-252</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;&lt;span style=&quot;color: rgb(64, 56, 56); font-family: 'Lucida Sans Unicode', Arial, 'Lucida Grande', Tahoma, Verdana, Helvetica, sans-serif; font-size: 12.8px; line-height: 19.2px;&quot;&gt;Persistently cold environments constitute one of our world&amp;#39;s largest ecosystems, and microorganisms dominate the biomass and metabolic activity in these extreme environments. The stress of low temperatures on life is exacerbated in organisms that rely on photoautrophic production of organic carbon and energy sources. Phototrophic organisms must coordinate temperature-independent reactions of light absorption and photochemistry with temperature-dependent processes of electron transport and utilization of energy sources through growth and metabolism. Despite this conundrum, phototrophic microorganisms thrive in all cold ecosystems described and (together with chemoautrophs) provide the base of autotrophic production in low-temperature food webs. Psychrophilic (organisms with a requirement for low growth temperatures) and psychrotolerant (organisms tolerant of low growth temperatures) photoautotrophs rely on low-temperature acclimative and adaptive strategies that have been described for other low-temperature-adapted heterotrophic organisms, such as cold-active proteins and maintenance of membrane fluidity. In addition, photoautrophic organisms possess other strategies to balance the absorption of light and the transduction of light energy to stored chemical energy products (NADPH and ATP) with downstream consumption of photosynthetically derived energy products at low temperatures. Lastly, differential adaptive and acclimative mechanisms exist in phototrophic microorganisms residing in low-temperature environments that are exposed to constant low-light environments versus high-light- and high-UV-exposed phototrophic assemblages.&lt;/span&gt;&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">1</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%">Cristina D. Takacs-Vesbach</style></author><author><style face="normal" font="default" size="100%">John C. Priscu</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%">Bacterial dissolved organic carbon demand in antarctic dry valley lakes</style></title><secondary-title><style face="normal" font="default" size="100%">Limnology and Oceanography</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Biggie</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2001</style></year><pub-dates><date><style  face="normal" font="default" size="100%">07/2001</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.jstor.org/stable/2671031</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">46</style></volume><pages><style face="normal" font="default" size="100%">1189-1194</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><issue><style face="normal" font="default" size="100%">7</style></issue><work-type><style face="normal" font="default" size="100%">Journal</style></work-type><accession-num><style face="normal" font="default" size="100%">LTER49824</style></accession-num></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%">John C. Priscu</style></author><author><style face="normal" font="default" size="100%">Christian H. Fritsen</style></author><author><style face="normal" font="default" size="100%">Edward E. Adams</style></author><author><style face="normal" font="default" size="100%">Stephen J. Giovannoni</style></author><author><style face="normal" font="default" size="100%">Hans W. Paerl</style></author><author><style face="normal" font="default" size="100%">Christopher P. McKay</style></author><author><style face="normal" font="default" size="100%">Peter T. Doran</style></author><author><style face="normal" font="default" size="100%">Douglas A. Gordon</style></author><author><style face="normal" font="default" size="100%">Brian D. Lanoil</style></author><author><style face="normal" font="default" size="100%">James L. Pinckney</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Perennial Antarctic Lake Ice:  An Oasis for Life in a Polar Desert</style></title><secondary-title><style face="normal" font="default" size="100%">Science</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Biggie</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1998</style></year><pub-dates><date><style  face="normal" font="default" size="100%">06/1998</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.sciencemag.org/content/280/5372/2095.short</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">280</style></volume><pages><style face="normal" font="default" size="100%">2095-2098</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><issue><style face="normal" font="default" size="100%">5372</style></issue><work-type><style face="normal" font="default" size="100%">Journal</style></work-type><accession-num><style face="normal" font="default" size="100%">LTER12940</style></accession-num></record></records></xml>