<?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%">Singley, Joel G.</style></author><author><style face="normal" font="default" size="100%">Gooseff, Michael N.</style></author><author><style face="normal" font="default" size="100%">Diane M. McKnight</style></author><author><style face="normal" font="default" size="100%">Eve-Lyn S. Hinckley</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">The role of hyporheic connectivity in determining nitrogen availability: Insights from an intermittent Antarctic stream</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Geophysical Research: Biogeosciences</style></secondary-title><short-title><style face="normal" font="default" size="100%">J Geophys Res Biogeosci</style></short-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Antarctica</style></keyword><keyword><style  face="normal" font="default" size="100%">autochthonous nitrogen</style></keyword><keyword><style  face="normal" font="default" size="100%">hyporheic zone</style></keyword><keyword><style  face="normal" font="default" size="100%">nitrogen cycling</style></keyword><keyword><style  face="normal" font="default" size="100%">streamflow</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%">04/2022</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021JG006309</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;Due to widespread manipulation of nitrogen (N), much research has focused on processes controlling the fate of anthropogenic N in streams. Yet, in a variety of oligotrophic systems, N fixed by periphyton is a significant driver of ecosystem metabolism. Due to difficulties partitioning allochthonous and autochthonous sources, there is limited information regarding how the latter is processed. Autochthonous N may be particularly important in alpine, arid, or polar environments. We test the hypothesis that the availability of remineralized autochthonous N is controlled by connectivity between the hyporheic zone and main channel due to the contrasting biogeochemical functions of benthic autotrophs (including N‐fixing &lt;em&gt;Nostoc&lt;/em&gt;) and hyporheic heterotrophs in an intermittent Antarctic stream. There, we collected surface water and hyporheic water concurrently at 4‐6 hour intervals over a 32.5‐hr period during one flow season and opportunistically throughout a second. Hyporheic water had 7 to 30 times greater nitrate‐N concentrations relative to surface water across all flow conditions. In contrast, ammonium concentrations were generally lower, although similar among locations. Additionally, nitrate in hyporheic water was positively correlated with silica, an indicator of hyporheic residence time. A laboratory assay confirmed prior inferences that hyporheic microbial communities possess the functional potential to perform nitrification. Together, these findings suggest that remineralized autochthonous N accumulates in the hyporheic zone even as streamflow varies and likely subsidizes stream N availability&amp;mdash;which supports prior inferences from N stable isotope data at this site. These results highlight the importance of hyporheic connectivity in controlling autochthonous N cycling and availability in streams.&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%">Tyler J. Kohler</style></author><author><style face="normal" font="default" size="100%">Ethan Chatfield</style></author><author><style face="normal" font="default" size="100%">Michael N. Gooseff</style></author><author><style face="normal" font="default" size="100%">John E. Barrett</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%">Recovery of Antarctic stream epilithon from simulated scouring events</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><dates><year><style  face="normal" font="default" size="100%">2015</style></year><pub-dates><date><style  face="normal" font="default" size="100%">Jan-08-2015</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.journals.cambridge.org/abstract_S0954102015000024</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">27</style></volume><pages><style face="normal" font="default" size="100%">341 - 354</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(98, 98, 98); font-family: 'Arial Unicode MS', Arial, Helvetica, sans-serif; font-size: 12px; line-height: 21.6000003814697px; background-color: rgb(241, 241, 241);&quot;&gt;Microbial mats are common in polar streams and often dominate benthic biomass. Climate change may be enhancing the variability of stream flows in the Antarctic, but so far studies investigating mat responses to disturbance have been limited in this region. Mat regrowth was evaluated following disturbance by experimentally scouring rocks from an ephemeral McMurdo Dry Valley stream over two summers (2001&amp;ndash;02 and 2012&amp;ndash;13). Mats were sampled at the beginning and resampled at the end of the flow season. In 2012&amp;ndash;13, mats were additionally resampled mid-season along with previously undisturbed controls. In 2001&amp;ndash;02 rocks regained 47% of chlorophyll&amp;nbsp;&lt;/span&gt;&lt;em style=&quot;outline: 0px; font-size: 12px; font-family: 'Arial Unicode MS', Arial, Helvetica, sans-serif; color: rgb(98, 98, 98); line-height: 21.6000003814697px; background-color: rgb(241, 241, 241);&quot;&gt;a&lt;/em&gt;&lt;span style=&quot;color: rgb(98, 98, 98); font-family: 'Arial Unicode MS', Arial, Helvetica, sans-serif; font-size: 12px; line-height: 21.6000003814697px; background-color: rgb(241, 241, 241);&quot;&gt;and 40% of ash-free dry mass by the end of the summer, while in 2012&amp;ndash;13 rocks regrew 18% and 27%, respectively. Mat stoichiometry differed between summers, and reflected differences in biomass and discharge.&amp;nbsp;&lt;/span&gt;&lt;em style=&quot;outline: 0px; font-size: 12px; font-family: 'Arial Unicode MS', Arial, Helvetica, sans-serif; color: rgb(98, 98, 98); line-height: 21.6000003814697px; background-color: rgb(241, 241, 241);&quot;&gt;Oscillatoria&lt;/em&gt;&lt;span style=&quot;color: rgb(98, 98, 98); font-family: 'Arial Unicode MS', Arial, Helvetica, sans-serif; font-size: 12px; line-height: 21.6000003814697px; background-color: rgb(241, 241, 241);&quot;&gt;&amp;nbsp;spp. were greatest on scoured rocks and&amp;nbsp;&lt;/span&gt;&lt;em style=&quot;outline: 0px; font-size: 12px; font-family: 'Arial Unicode MS', Arial, Helvetica, sans-serif; color: rgb(98, 98, 98); line-height: 21.6000003814697px; background-color: rgb(241, 241, 241);&quot;&gt;Phormidium&lt;/em&gt;&lt;span style=&quot;color: rgb(98, 98, 98); font-family: 'Arial Unicode MS', Arial, Helvetica, sans-serif; font-size: 12px; line-height: 21.6000003814697px; background-color: rgb(241, 241, 241);&quot;&gt;&amp;nbsp;spp. on undisturbed rocks. Small diatoms&amp;nbsp;&lt;/span&gt;&lt;em style=&quot;outline: 0px; font-size: 12px; font-family: 'Arial Unicode MS', Arial, Helvetica, sans-serif; color: rgb(98, 98, 98); line-height: 21.6000003814697px; background-color: rgb(241, 241, 241);&quot;&gt;Humidophila&lt;/em&gt;&lt;span style=&quot;color: rgb(98, 98, 98); font-family: 'Arial Unicode MS', Arial, Helvetica, sans-serif; font-size: 12px; line-height: 21.6000003814697px; background-color: rgb(241, 241, 241);&quot;&gt;&amp;nbsp;and&lt;/span&gt;&lt;em style=&quot;outline: 0px; font-size: 12px; font-family: 'Arial Unicode MS', Arial, Helvetica, sans-serif; color: rgb(98, 98, 98); line-height: 21.6000003814697px; background-color: rgb(241, 241, 241);&quot;&gt;Fistulifera&lt;/em&gt;&lt;span style=&quot;color: rgb(98, 98, 98); font-family: 'Arial Unicode MS', Arial, Helvetica, sans-serif; font-size: 12px; line-height: 21.6000003814697px; background-color: rgb(241, 241, 241);&quot;&gt;&amp;nbsp;spp. increased throughout the summer in all mats, with the latter more abundant in scoured communities. Collectively, these data suggest that mats are variable intra-annually, responsive to hydrology and require multiple summers to regrow initial biomass once lost. These results will aid the interpretation of long-term data, as well as inform Antarctic Specially Managed Area protocols.&lt;/span&gt;&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">04</style></issue></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%">Cullis, James D.S.</style></author></authors><secondary-authors><author><style face="normal" font="default" size="100%">Diane M. McKnight</style></author></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Removal of benthic algae in swift-flowing streams: The significance of spatial and temporal variation in shear stress and bed disturbance</style></title><secondary-title><style face="normal" font="default" size="100%">Department of Civil, Environmental and Architectural Engineering</style></secondary-title></titles><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://search.proquest.com/docview/916604693?accountid=14503</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%">263</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;&amp;nbsp;&lt;/p&gt;&lt;div title=&quot;Page 4&quot;&gt;&lt;div&gt;&lt;div&gt;&lt;p&gt;In this thesis I investigate the role of spatial and temporal dynamics of flow, bed shear stress, and bed disturbance on the removal of benthic algal and the consequences for our understanding of the dynamics of stream ecosystems and the transport of organic matter in fluvial systems. I use data obtained from two specific case studies where benthic algal mats are key components in the overall system dynamics. The first case study investigates spatial and temporal variations in particular organic matter transport derived from the removal of benthic algae in a stream in the McMurdo Dry Valleys of Antarctica. The second case study uses a combination of field observations and analysis, one and two dimensional hydraulic modeling, and laboratory flume studies to investigate the controls on the removal of the stalk forming diatom&amp;nbsp;&lt;em&gt;Didymosphenia geminata&lt;/em&gt;. The results show that benthic algae growing in swift-flowing streams are well adapted to this environment. Hence the removal of organic material due to elevated shear stress alone is limited and effective control of nuisance blooms of benthic algae such as&amp;nbsp;&lt;em&gt;D. geminata&lt;/em&gt;&amp;nbsp;requires flood events sufficiently high enough to results in wide spread disturbance of the stream substrate. These flow requirements are similar to the requirements for channel maintenance flows and could therefore be considered for inclusion in the operating rules for dams in order to maintain the diversity of stream ecosystems and functioning water supply infrastructure.&lt;/p&gt;&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;p&gt;&amp;nbsp;&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>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Diane M. McKnight</style></author><author><style face="normal" font="default" size="100%">Cathy M. Tate</style></author><author><style face="normal" font="default" size="100%">Edmund D. Andrews</style></author><author><style face="normal" font="default" size="100%">Dev K. Niyogi</style></author><author><style face="normal" font="default" size="100%">Cozzetto, K</style></author><author><style face="normal" font="default" size="100%">Kathleen A. Welch</style></author><author><style face="normal" font="default" size="100%">W. Berry Lyons</style></author><author><style face="normal" font="default" size="100%">D. G. Capone</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Reactivation of a cryptobiotic stream ecosystem in the McMurdo Dry Valleys, Antarctica: A long-term geomorphological experiment</style></title><secondary-title><style face="normal" font="default" size="100%">Geomorphology</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2007</style></year><pub-dates><date><style  face="normal" font="default" size="100%">09/2007</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">89</style></volume><pages><style face="normal" font="default" size="100%">186-204</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><issue><style face="normal" font="default" size="100%">1-2</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%">Michael N. Gooseff</style></author><author><style face="normal" font="default" size="100%">Diane M. McKnight</style></author><author><style face="normal" font="default" size="100%">Robert L. Runkel</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Reach-scale cation exchange controls on major ion chemistry of an Antarctic glacial meltwater stream</style></title><secondary-title><style face="normal" font="default" size="100%">Special issue of Aquatic Geochemistry on the McMurdo Dry Valleys</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2004</style></year></dates><volume><style face="normal" font="default" size="100%">10</style></volume><pages><style face="normal" font="default" size="100%">221-238</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><issue><style face="normal" font="default" size="100%">3</style></issue><accession-num><style face="normal" font="default" size="100%">LTER63369</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 E. Walsh</style></author><author><style face="normal" font="default" size="100%">Gary D. Clow</style></author><author><style face="normal" font="default" size="100%">Christian H. Fritsen</style></author><author><style face="normal" font="default" size="100%">Christopher P. McKay</style></author><author><style face="normal" font="default" size="100%">Andrew N. Parsons</style></author><author><style face="normal" font="default" size="100%">Peter T. Doran</style></author><author><style face="normal" font="default" size="100%">John C. Priscu</style></author><author><style face="normal" font="default" size="100%">W. Berry Lyons</style></author><author><style face="normal" font="default" size="100%">Andrew G Fountain</style></author><author><style face="normal" font="default" size="100%">Diane M. McKnight</style></author><author><style face="normal" font="default" size="100%">Daryl L. Moorhead</style></author><author><style face="normal" font="default" size="100%">Ross A. Virginia</style></author><author><style face="normal" font="default" size="100%">Diana H. Wall</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Recent Temperature Trends in the Antarctic</style></title><secondary-title><style face="normal" font="default" size="100%">Nature</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2002</style></year></dates><volume><style face="normal" font="default" size="100%">418</style></volume><pages><style face="normal" font="default" size="100%">291-292</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><accession-num><style face="normal" font="default" size="100%">LTER49851</style></accession-num></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%">Ethan Chatfield</style></author></authors><tertiary-authors><author><style face="normal" font="default" size="100%">Diane M. McKnight</style></author></tertiary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Regrowth of cyanobacterial mats in Greek Creek and the impact of ecotourism</style></title></titles><dates><year><style  face="normal" font="default" size="100%">2001</style></year></dates><publisher><style face="normal" font="default" size="100%">University of Colorado</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><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>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Bomblies, Arne</style></author><author><style face="normal" font="default" size="100%">Diane M. McKnight</style></author><author><style face="normal" font="default" size="100%">Edmund D. Andrews</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Retrospective simulation of lake level rise in Lake Bonney based on recent 21-year record: indication of recent climate change in the McMurdo Dry Valleys, Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Paleolimnology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Climate Response</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2001</style></year></dates><volume><style face="normal" font="default" size="100%">25</style></volume><pages><style face="normal" font="default" size="100%">477-492</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><accession-num><style face="normal" font="default" size="100%">LTER49840</style></accession-num></record></records></xml>