<?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%">Garrett P. Rue</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%">Chemical signatures of microbial life in an ecological end-member: Shifting hydroclimate and sediment fluxes influence DOM biogeochemistry in Lake Fryxell, a permanently ice-covered lake in the McMurdo Dry Valleys of Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">Arctic, Antarctic, and Alpine Research</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%">DOM</style></keyword><keyword><style  face="normal" font="default" size="100%">lake metabolism</style></keyword><keyword><style  face="normal" font="default" size="100%">limnology</style></keyword><keyword><style  face="normal" font="default" size="100%">nutrient cycling</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2025</style></year><pub-dates><date><style  face="normal" font="default" size="100%">04/2025</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.tandfonline.com/doi/full/10.1080/15230430.2025.2478678</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">57</style></volume><pages><style face="normal" font="default" size="100%">2478678</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The ice-covered lakes in the McMurdo Dry Valleys (MDV) of Antarctica provide end-member ecosystems for understanding the production of dissolved organic matter (DOM) in aquatic ecosystems in the absence of vegetation on the landscape and under resource and nutrient constraints. Given these constraints, DOM in MDV lakes is derived solely from microbial phototrophs and heterotrophic bacteria, contrasting with the dominant terrestrial sources in temperate regions. Previous research developed fluorometric approaches for characterizing DOM, including in MDV lakes. In this study we leveraged these approaches along with contemporary molecular-based techniques to elucidate changes in DOM composition across the depth profile for Lake Fryxell in the MDV. The results showed that the presence of organic molecules containing sulfur increased at depth where anoxic conditions prevailed. To evaluate the influences of climate-induced rising lake levels and multiple flood events in the MDV, we compared recent and historical samples. The results indicated a remarkable consistency in source-related fluorescence metrics over time, whereas a twofold decrease in sulfur content of the fulvic acid fraction was observed in samples from above and below the oxycline. Biogeochemical processes associated with the influx of iron oxide&amp;ndash;rich sediments during flood events may have contributed to this change, and similar processes may stimulate biogeochemical cycling and remineralization in temperate lakes during seasonal transitions.&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%">Jankowski, Kathi Jo</style></author><author><style face="normal" font="default" size="100%">Johnson, Keira</style></author><author><style face="normal" font="default" size="100%">Sethna, Lienne</style></author><author><style face="normal" font="default" size="100%">Julian, Paul</style></author><author><style face="normal" font="default" size="100%">Wymore, Adam S.</style></author><author><style face="normal" font="default" size="100%">Shogren, Arial J.</style></author><author><style face="normal" font="default" size="100%">Thomas, Patrick K.</style></author><author><style face="normal" font="default" size="100%">Sullivan, Pamela L.</style></author><author><style face="normal" font="default" size="100%">Diane M. McKnight</style></author><author><style face="normal" font="default" size="100%">McDowell, William H.</style></author><author><style face="normal" font="default" size="100%">Heindel, Ruth C</style></author><author><style face="normal" font="default" size="100%">Jones, Jeremy B.</style></author><author><style face="normal" font="default" size="100%">Wollheim, Wilfred</style></author><author><style face="normal" font="default" size="100%">Abbott, Benjamin</style></author><author><style face="normal" font="default" size="100%">Deegan, Linda</style></author><author><style face="normal" font="default" size="100%">Carey, Joanna C.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Long-term changes in concentration and yield of riverine dissolved silicon from the poles to the tropics</style></title><secondary-title><style face="normal" font="default" size="100%">Global Biogeochemical Cycles</style></secondary-title><short-title><style face="normal" font="default" size="100%">Global Biogeochemical Cycles</style></short-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">biogeochemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">river</style></keyword><keyword><style  face="normal" font="default" size="100%">silica</style></keyword><keyword><style  face="normal" font="default" size="100%">silicon</style></keyword><keyword><style  face="normal" font="default" size="100%">stream</style></keyword><keyword><style  face="normal" font="default" size="100%">trends</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%">08/2023</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GB007678</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;Riverine exports of silicon (Si) influence global carbon cycling through the growth of marine diatoms, which account for &amp;sim;25% of global primary production. Climate change will likely alter river Si exports in biome-specific ways due to interacting shifts in chemical weathering rates, hydrologic connectivity, and metabolic processes in aquatic and terrestrial systems. Nonetheless, factors driving long-term changes in Si exports remain unexplored at local, regional, and global scales. We evaluated how concentrations and yields of dissolved Si (DSi) changed over the last several decades of rapid climate warming using long-term datasets from 60 rivers and streams spanning the globe (e.g., Antarctic, tropical, temperate, boreal, alpine, Arctic systems). We show that widespread changes in river DSi concentration and yield have occurred, with the most substantial shifts occurring in alpine and polar regions. The magnitude and direction of trends varied within and among biomes, were most strongly associated with differences in land cover, and were often independent of changes in river discharge. These findings indicate that there are likely diverse mechanisms driving change in river Si biogeochemistry that span the land-water interface, which may include glacial melt, changes in terrestrial vegetation, and river productivity. Finally, trends were often stronger in months outside of the growing season, particularly in temperate and boreal systems, demonstrating a potentially important role of shifting seasonality for the flux of Si from rivers. Our results have implications for the timing and magnitude of silica processing in rivers and its delivery to global oceans.&lt;/p&gt;</style></abstract></record></records></xml>