<?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%">Robinson, Colin Michael</style></author><author><style face="normal" font="default" size="100%">Hansen, Lee D.</style></author><author><style face="normal" font="default" size="100%">Xue, Xia</style></author><author><style face="normal" font="default" size="100%">Adams, Byron J.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Temperature response of metabolic activity of an Antarctic nematode</style></title><secondary-title><style face="normal" font="default" size="100%">Biology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Antarctica</style></keyword><keyword><style  face="normal" font="default" size="100%">carbon cycling</style></keyword><keyword><style  face="normal" font="default" size="100%">climate change</style></keyword><keyword><style  face="normal" font="default" size="100%">nematode</style></keyword><keyword><style  face="normal" font="default" size="100%">respiration rates</style></keyword><keyword><style  face="normal" font="default" size="100%">soil temperature</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%">01/2023</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.mdpi.com/2079-7737/12/1/109</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">12</style></volume><pages><style face="normal" font="default" size="100%">109</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Because of climate change, the McMurdo Dry Valleys of Antarctica (MCM) have experienced an increase in the frequency and magnitude of summer pulse warming and surface ice and snow melting events. In response to these environmental changes, some nematode species in the MCM have experienced steady population declines over the last three decades, but &lt;i&gt;Plectus murrayi&lt;/i&gt;, a mesophilic nematode species, has responded with a steady increase in range and abundance. To determine how &lt;i&gt;P. murrayi&lt;/i&gt; responds to increasing temperatures, we measured metabolic heat and CO&lt;sub&gt;2&lt;/sub&gt; production rates and calculated O&lt;sub&gt;2&lt;/sub&gt; consumption rates as a function of temperature at 5 &amp;deg;C intervals from 5 to 50 &amp;deg;C. Heat, CO&lt;sub&gt;2&lt;/sub&gt; production, and O&lt;sub&gt;2&lt;/sub&gt; consumption rates increase approximately exponentially up to 40 &amp;deg;C, a temperature never experienced in their polar habitat. Metabolic rates decline rapidly above 40 &amp;deg;C and are irreversibly lost at 50 &amp;deg;C due to thermal stress and mortality. &lt;i&gt;Caenorhabditis elegans&lt;/i&gt;, a much more widespread nematode that is found in more temperate environments reaches peak metabolic heat rate at just 27 &amp;deg;C, above which it experiences high mortality due to thermal stress. At temperatures from 10 to 40 &amp;deg;C, &lt;i&gt;P. murrayi&lt;/i&gt; produces about 6 times more CO&lt;sub&gt;2&lt;/sub&gt; than the O&lt;sub&gt;2&lt;/sub&gt; it consumes, a respiratory quotient indicative of either acetogenesis or de novo lipogenesis. No potential acetogenic microbes were identified in the &lt;i&gt;P. murrayi&lt;/i&gt; microbiome, suggesting that &lt;i&gt;P. murrayi&lt;/i&gt; is producing increased CO&lt;sub&gt;2&lt;/sub&gt; as a byproduct of de novo lipogenesis. This phenomenon, in conjunction with increased summer temperatures in their polar habitat, will likely lead to increased demand for carbon and subsequent increases in CO&lt;sub&gt;2&lt;/sub&gt; production, population abundance, and range expansion. If such changes are not concomitant with increased carbon inputs, we predict the MCM soil ecosystems will experience dramatic declines in functional and taxonomic diversity.&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%">Heindel, Ruth C</style></author><author><style face="normal" font="default" size="100%">Darling, Joshua P.</style></author><author><style face="normal" font="default" size="100%">Singley, Joel G.</style></author><author><style face="normal" font="default" size="100%">Bergstrom, Anna J.</style></author><author><style face="normal" font="default" size="100%">Diane M. McKnight</style></author><author><style face="normal" font="default" size="100%">Lukkari, Braeden M.</style></author><author><style face="normal" font="default" size="100%">Kathleen A. Welch</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%">Diatoms in hyporheic sediments trace organic matter retention and processing in the McMurdo Dry Valleys, Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Geophysical Research: Biogeosciences</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">benthic processes</style></keyword><keyword><style  face="normal" font="default" size="100%">biogenic silica</style></keyword><keyword><style  face="normal" font="default" size="100%">biogeochemical cycles processes and modeling</style></keyword><keyword><style  face="normal" font="default" size="100%">carbon cycling</style></keyword><keyword><style  face="normal" font="default" size="100%">diatoms</style></keyword><keyword><style  face="normal" font="default" size="100%">groundwater/surface water interactions</style></keyword><keyword><style  face="normal" font="default" size="100%">hyporheic zone</style></keyword><keyword><style  face="normal" font="default" size="100%">McMurdo Dry Valleys</style></keyword><keyword><style  face="normal" font="default" size="100%">nitrogen cycling</style></keyword><keyword><style  face="normal" font="default" size="100%">particulate organic matter</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%">02/2021</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JG006097</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">126</style></volume><pages><style face="normal" font="default" size="100%">e2020JG006097</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;In low‐nutrient streams in cold and arid ecosystems, the spiraling of autochthonous particulate organic matter (POM) may provide important nutrient subsidies downstream. Because of its lability and the spatial heterogeneity of processing in hyporheic sediments, the downstream transport and fate of autochthonous POM can be difficult to trace. In Antarctic McMurdo Dry Valley (MDV) streams, any POM retained in the hyporheic zone is expected to be derived from surface microbial mats that contain diatoms with long‐lasting silica frustules. We tested whether diatom frustules can be used to trace the retention of autochthonous POM in the hyporheic zone and whether certain geomorphic locations promote this process. The accumulation of diatom frustules in hyporheic sediments, measured as biogenic silica, was correlated with loss‐on‐ignition organic matter and sorbed ammonium, suggesting that diatoms can be used to identify locations where POM has been retained and processed over long timescales, regardless of whether the POM remains intact. In addition, by modeling the upstream sources of hyporheic diatom assemblages, we found that POM was predominantly derived from N‐fixing microbial mats of the genus Nostoc. In terms of spatial variability, we conclude that the hyporheic sediments adjacent to the stream channel that are regularly inundated by daily flood pulses are where the most POM has been retained over long timescales. Autochthonous POM is retained in hyporheic zones of low‐nutrient streams beyond the MDVs, and we suggest that biogenic silica and diatom composition can be used to identify locations where this transfer is most prevalent.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue></record></records></xml>