<?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%">Evans, Thomas W.</style></author><author><style face="normal" font="default" size="100%">Kalambokidis, Maria J.</style></author><author><style face="normal" font="default" size="100%">Jungblut, Anne D.</style></author><author><style face="normal" font="default" size="100%">Millar, Jasmin L.</style></author><author><style face="normal" font="default" size="100%">Bauersachs, Thorsten</style></author><author><style face="normal" font="default" size="100%">Grotheer, Hendrik</style></author><author><style face="normal" font="default" size="100%">Mackey, Tyler J.</style></author><author><style face="normal" font="default" size="100%">Ian Hawes</style></author><author><style face="normal" font="default" size="100%">Summons, Roger E.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Lipid biomarkers from microbial mats on the McMurdo Ice Shelf, Antarctica: Signatures for life in the cryosphere</style></title><secondary-title><style face="normal" font="default" size="100%">Frontiers in Microbiology</style></secondary-title><short-title><style face="normal" font="default" size="100%">Front. Microbiol.</style></short-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Antarctica</style></keyword><keyword><style  face="normal" font="default" size="100%">bacteriohopanepolyol</style></keyword><keyword><style  face="normal" font="default" size="100%">cyanobacteria</style></keyword><keyword><style  face="normal" font="default" size="100%">heterocyte glycolipids</style></keyword><keyword><style  face="normal" font="default" size="100%">homeoviscous adaptation</style></keyword><keyword><style  face="normal" font="default" size="100%">intact polar lipid</style></keyword><keyword><style  face="normal" font="default" size="100%">microbial mats</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2022</style></year><pub-dates><date><style  face="normal" font="default" size="100%">06/2022</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.frontiersin.org/articles/10.3389/fmicb.2022.903621/full</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">13</style></volume><pages><style face="normal" font="default" size="100%">903621</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Persistent cold temperatures, a paucity of nutrients, freeze-thaw cycles, and the strongly seasonal light regime make Antarctica one of Earth&amp;rsquo;s least hospitable surface environments for complex life. Cyanobacteria, however, are well-adapted to such conditions and are often the dominant primary producers in Antarctic inland water environments. In particular, the network of meltwater ponds on the &amp;lsquo;dirty ice&amp;rsquo; of the McMurdo Ice Shelf is an ecosystem with extensive cyanobacteria-dominated microbial mat accumulations. This study investigated intact polar lipids (IPLs), heterocyte glycolipids (HGs), and bacteriohopanepolyols (BHPs) in combination with 16S and 18S rRNA gene diversity in microbial mats of twelve ponds in this unique polar ecosystem. To constrain the effects of nutrient availability, temperature and freeze-thaw cycles on the lipid membrane composition, lipids were compared to stromatolite-forming cyanobacterial mats from ice-covered lakes in the McMurdo Dry Valleys as well as from (sub)tropical regions and hot springs. The 16S rRNA gene compositions of the McMurdo Ice Shelf mats confirm the dominance of Cyanobacteria and Proteobacteria while the 18S rRNA gene composition indicates the presence of Ochrophyta, Chlorophyta, Ciliophora, and other microfauna. IPL analyses revealed a predominantly bacterial community in the meltwater ponds, with archaeal lipids being barely detectable. IPLs are dominated by glycolipids and phospholipids, followed by aminolipids. The high abundance of sugar-bound lipids accords with a predominance of cyanobacterial primary producers. The phosphate-limited samples from the (sub)tropical, hot spring, and Lake Vanda sites revealed a higher abundance of aminolipids compared to those of the nitrogen-limited meltwater ponds, affirming the direct affects that N and P availability have on IPL compositions. The high abundance of polyunsaturated IPLs in the Antarctic microbial mats suggests that these lipids provide an important mechanism to maintain membrane fluidity in cold environments. High abundances of HG keto-ols and HG keto-diols, produced by heterocytous cyanobacteria, further support these findings and reveal a unique distribution compared to those from warmer climates.&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%">Lumian, Jessica E.</style></author><author><style face="normal" font="default" size="100%">Jungblut, Anne D.</style></author><author><style face="normal" font="default" size="100%">Dillon, Megan L.</style></author><author><style face="normal" font="default" size="100%">Hawes, Ian</style></author><author><style face="normal" font="default" size="100%">Peter T. Doran</style></author><author><style face="normal" font="default" size="100%">Mackey, Tyler J.</style></author><author><style face="normal" font="default" size="100%">Dick, Gregory J.</style></author><author><style face="normal" font="default" size="100%">Grettenberger, Christen L.</style></author><author><style face="normal" font="default" size="100%">Sumner, Dawn Y.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Metabolic capacity of the Antarctic cyanobacterium &lt;I&gt;Phormidium pseudopriestleyi&lt;/I&gt; that sustains oxygenic photosynthesis in the presence of hydrogen sulfide</style></title><secondary-title><style face="normal" font="default" size="100%">Genes</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2021</style></year><pub-dates><date><style  face="normal" font="default" size="100%">03/2021</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.mdpi.com/2073-4425/12/3/426</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">12</style></volume><pages><style face="normal" font="default" size="100%">426</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Sulfide inhibits oxygenic photosynthesis by blocking electron transfer between H&lt;sub&gt;2&lt;/sub&gt;O and the oxygen-evolving complex in the D1 protein of Photosystem II. The ability of cyanobacteria to counter this effect has implications for understanding the productivity of benthic microbial mats in sulfidic environments throughout Earth history. In Lake Fryxell, Antarctica, the benthic, filamentous cyanobacterium &lt;em&gt;Phormidium pseudopriestleyi&lt;/em&gt; creates a 1&amp;ndash;2 mm thick layer of 50 &amp;micro;mol L&lt;sup&gt;&amp;minus;1&lt;/sup&gt; O&lt;sub&gt;2&lt;/sub&gt; in otherwise sulfidic water, demonstrating that it sustains oxygenic photosynthesis in the presence of sulfide. A metagenome-assembled genome of &lt;em&gt;P. pseudopriestleyi&lt;/em&gt; indicates a genetic capacity for oxygenic photosynthesis, including multiple copies of &lt;em&gt;psbA&lt;/em&gt; (encoding the D1 protein of Photosystem II), and anoxygenic photosynthesis with a copy of &lt;em&gt;sqr&lt;/em&gt; (encoding the sulfide quinone reductase protein that oxidizes sulfide). The genomic content of &lt;em&gt;P. pseudopriestleyi&lt;/em&gt; is consistent with sulfide tolerance mechanisms including increasing &lt;em&gt;psbA&lt;/em&gt; expression or directly oxidizing sulfide with sulfide quinone reductase. However, the ability of the organism to reduce Photosystem I via sulfide quinone reductase while Photosystem II is sulfide-inhibited, thereby performing anoxygenic photosynthesis in the presence of sulfide, has yet to be demonstrated.&amp;nbsp;&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">3</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%">Dillon, Megan L.</style></author><author><style face="normal" font="default" size="100%">Ian Hawes</style></author><author><style face="normal" font="default" size="100%">Jungblut, Anne D.</style></author><author><style face="normal" font="default" size="100%">Mackey, Tyler J.</style></author><author><style face="normal" font="default" size="100%">Eisen, Jonathan A.</style></author><author><style face="normal" font="default" size="100%">Peter T. Doran</style></author><author><style face="normal" font="default" size="100%">Sumner, Dawn Y.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Energetic and environmental constraints on the community structure of benthic microbial mats in Lake Fryxell, Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">FEMS Microbiology Ecology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Antarctica</style></keyword><keyword><style  face="normal" font="default" size="100%">energy</style></keyword><keyword><style  face="normal" font="default" size="100%">Lake Fryxell</style></keyword><keyword><style  face="normal" font="default" size="100%">microbial mat</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxygen</style></keyword><keyword><style  face="normal" font="default" size="100%">Photosynthetically Active Radiation</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%">02/2020</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://academic.oup.com/femsec/article/96/2/fiz207/5697196</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">96</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Ecological communities are regulated by the flow of energy through environments. Energy flow is typically limited by access to photosynthetically active radiation (PAR) and oxygen concentration (O&lt;sub&gt;2&lt;/sub&gt;). The microbial mats growing on the bottom of Lake Fryxell, Antarctica, have well-defined environmental gradients in PAR and (O&lt;sub&gt;2&lt;/sub&gt;). We analyzed the metagenomes of layers from these microbial mats to test the extent to which access to oxygen and light controls community structure. We found variation in the diversity and relative abundances of Archaea, Bacteria and Eukaryotes across three (O&lt;sub&gt;2&lt;/sub&gt;) and PAR conditions: high (O&lt;sub&gt;2&lt;/sub&gt;) and maximum PAR, variable (O&lt;sub&gt;2&lt;/sub&gt;) with lower maximum PAR, and low (O&lt;sub&gt;2&lt;/sub&gt;) and maximum PAR. We found distinct communities structured by the optimization of energy use on a millimeter-scale across these conditions. In mat layers where (O&lt;sub&gt;2&lt;/sub&gt;) was saturated, PAR structured the community. In contrast, (O&lt;sub&gt;2&lt;/sub&gt;) positively correlated with diversity and affected the distribution of dominant populations across the three habitats, suggesting that meter-scale diversity is structured by energy availability. Microbial communities changed across covarying gradients of PAR and (O&lt;sub&gt;2&lt;/sub&gt;). The comprehensive metagenomic analysis suggests that the benthic microbial communities in Lake Fryxell are structured by energy flow across both meter- and millimeter-scales.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">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%">Dillon, Megan L.</style></author><author><style face="normal" font="default" size="100%">Hawes, Ian</style></author><author><style face="normal" font="default" size="100%">Jungblut, Anne D.</style></author><author><style face="normal" font="default" size="100%">Mackey, Tyler J.</style></author><author><style face="normal" font="default" size="100%">Eisen, Jonathan A.</style></author><author><style face="normal" font="default" size="100%">Peter T. Doran</style></author><author><style face="normal" font="default" size="100%">Sumner, Dawn Y.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Environmental control on the distribution of metabolic strategies of benthic microbial mats in Lake Fryxell, Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">PLoS ONE</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2020</style></year><pub-dates><date><style  face="normal" font="default" size="100%">04/2020</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0231053</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">15</style></volume><pages><style face="normal" font="default" size="100%">e0231053</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Ecological theories posit that heterogeneity in environmental conditions greatly affects community structure and function. However, the degree to which ecological theory developed using plant- and animal-dominated systems applies to microbiomes is unclear. Investigating the metabolic strategies found in microbiomes are particularly informative for testing the universality of ecological theories because microorganisms have far wider metabolic capacity than plants and animals. We used metagenomic analyses to explore the relationships between the energy and physicochemical gradients in Lake Fryxell and the metabolic capacity of its benthic microbiome. Statistical analysis of the relative abundance of metabolic marker genes and gene family diversity shows that oxygenic photosynthesis, carbon fixation, and flavin-based electron bifurcation differentiate mats growing in different environmental conditions. The pattern of gene family diversity points to the likely importance of temporal environmental heterogeneity in addition to resource gradients. Overall, we found that the environmental heterogeneity of photosynthetically active radiation (PAR) and oxygen concentration ([O&lt;sub&gt;2&lt;/sub&gt;]) in Lake Fryxell provide the framework by which metabolic diversity and composition of the community is structured, in accordance with its phylogenetic structure. The organization of the resulting microbial ecosystems are consistent with the maximum power principle and the species sorting model.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">4</style></issue></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%">Ian Hawes</style></author><author><style face="normal" font="default" size="100%">Sumner, Dawn Y.</style></author><author><style face="normal" font="default" size="100%">Jungblut, Anne D.</style></author></authors><secondary-authors><author><style face="normal" font="default" size="100%">Hurst, Christon J.</style></author></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Complex Structure but Simple Function in Microbial Mats from Antarctic Lakes</style></title><secondary-title><style face="normal" font="default" size="100%">The Structure and Function of Aquatic Microbial Communities</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">biofilm</style></keyword><keyword><style  face="normal" font="default" size="100%">microbial ecology</style></keyword><keyword><style  face="normal" font="default" size="100%">microbial structures</style></keyword><keyword><style  face="normal" font="default" size="100%">self-organising structures</style></keyword><keyword><style  face="normal" font="default" size="100%">stromatolite</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2019</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://link.springer.com/chapter/10.1007/978-3-030-16775-2_4</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">Springer International Publishing</style></publisher><pub-location><style face="normal" font="default" size="100%">Cham</style></pub-location><pages><style face="normal" font="default" size="100%">91 - 120</style></pages><isbn><style face="normal" font="default" size="100%">978-3-030-16775-2</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Microbial mats growing under the permanent ice cover of Antarctic lakes occupy an exceptionally low-disturbance regime. Constant temperature, the absence of bioturbation or physical disturbance from wind action or ice formation allow mats to accumulate, as annual growth layers, over many decades or even centuries. In so doing they often assume decimetre scale, three-dimensional morphologies such as elaborate pinnacle structures and conical mounds. Here we combine existing and new information to describe microbial structures in three Antarctic lakes&amp;mdash;simple prostrate mats in Lake Hoare, emergent cones in Lake Untersee and elaborate pinnacles in Lake Vanda. We attempt to determine whether structures emerge simply from uncoordinated organism-environment interactions or whether they represent an example of &amp;ldquo;emergent complexity&amp;rdquo;, within which some degree of self-organisation occurs to confer a holistic functional advantage to component organisms. While some holistic advantages were evident from the structures&amp;mdash;the increase in surface area allows greater biomass and overall productivity and nutrient exchange with overlying water&amp;mdash;the structures could also be understood in terms of potential interactions between individuals, their orientation and their environment. The data lack strong evidence of coordinated behaviour directed towards holistic advantages to the structure, though hints of coordinated behaviour are present as non-random distributions of structural elements. The great size of microbial structures in Antarctic lakes, and their relatively simple community composition, makes them excellent models for more focused research on microbial cooperation.&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%">Matys, Emily D.</style></author><author><style face="normal" font="default" size="100%">Mackey, Tyler J.</style></author><author><style face="normal" font="default" size="100%">Grettenberger, Christen</style></author><author><style face="normal" font="default" size="100%">Mueller, Elliott</style></author><author><style face="normal" font="default" size="100%">Jungblut, Anne D.</style></author><author><style face="normal" font="default" size="100%">Sumner, Dawn Y.</style></author><author><style face="normal" font="default" size="100%">Ian Hawes</style></author><author><style face="normal" font="default" size="100%">Summons, Roger E.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Environmental controls on bacteriohopanepolyol profiles of benthic microbial mats from Lake Fryxell, Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">Geobiology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">anammox</style></keyword><keyword><style  face="normal" font="default" size="100%">bacteriohopanepolyol</style></keyword><keyword><style  face="normal" font="default" size="100%">bacteriohopanetetrol isomer</style></keyword><keyword><style  face="normal" font="default" size="100%">biomarker</style></keyword><keyword><style  face="normal" font="default" size="100%">McMurdo Dry Valleys</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2019</style></year><pub-dates><date><style  face="normal" font="default" size="100%">07/2019</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://onlinelibrary.wiley.com/doi/full/10.1111/gbi.12353</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;Bacteriohopanepolyols (BHPs) are pentacyclic triterpenoid lipids that contribute to the structural integrity and physiology of some bacteria. Because some BHPs originate from specific classes of bacteria, BHPs have potential as taxonomically and environmentally diagnostic biomarkers. For example, a stereoisomer of bacteriohopanetetrol (informally BHT II) has been associated with anaerobic ammonium oxidation (anammox) bacteria and suboxic to anoxic marine environments where anammox is active. As a result, the detection of BHT II in the sedimentary record and fluctuations in the relative abundance of BHT II may inform reconstructions of nitrogen cycling and ocean redox changes through the geological record. However, there are uncertainties concerning the sources of BHT II and whether or not BHT II is produced in abundance in non‐marine environments, both of which are pertinent to interpretations of BHT II signatures in sediments. To address these questions, we investigate the BHP composition of benthic microbial mats from Lake Fryxell, Antarctica. Lake Fryxell is a perennially ice‐covered lake with a sharp oxycline in a density‐stabilized water column. We describe the diversity and abundance of BHPs in benthic microbial mats across a transect from oxic to anoxic conditions. Generally, BHP abundances and diversity vary with the morphologies of microbial mats, which were previously shown to reflect local environmental conditions, such as irradiance and oxygen and sulfide concentrations. BHT II was identified in mats that exist within oxic to anoxic portions of the lake. However, anammox bacteria have yet to be identified in Lake Fryxell. We examine our results in the context of BHPs as biomarkers in modern and ancient environments.&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%">Ian Hawes</style></author><author><style face="normal" font="default" size="100%">Jungblut, Anne D.</style></author><author><style face="normal" font="default" size="100%">Maciek K. Obryk</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%">Growth dynamics of a laminated microbial mat in response to variable irradiance in an Antarctic lake</style></title><secondary-title><style face="normal" font="default" size="100%">Freshwater Biology</style></secondary-title><short-title><style face="normal" font="default" size="100%">Freshw Biol</style></short-title></titles><dates><year><style  face="normal" font="default" size="100%">2016</style></year><pub-dates><date><style  face="normal" font="default" size="100%">02/2016</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://doi.wiley.com/10.1111/fwb.12715</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">61</style></volume><pages><style face="normal" font="default" size="100%">396 - 410</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;ol class=&quot;o-list--numbered o-list--paragraph&quot; id=&quot;fwb12715-list-0001&quot; style=&quot;margin-top: 0px; margin-bottom: 3em; margin-left: 6em; outline: 0px; font-size: 10px; list-style-position: outside; color: rgb(51, 51, 51); font-family: 'Open Sans', Arial, Helvetica, 'Lucida Sans Unicode', sans-serif; line-height: 14px; background: 0px 0px rgb(249, 249, 249);&quot;&gt;&lt;li style=&quot;margin-bottom: 0.8em; padding-left: 0.5em; outline: 0px; font-size: 1.6em; background: 0px 0px;&quot;&gt;Laminated microbial mats are important ecosystem components of perennially ice-covered Antarctic dry valley lakes. In order to understand better their response to changing environment, we made observations and carried out a manipulation experiment to determine their response to variations in irradiance in Lake Hoare (77&amp;deg;38&amp;prime; S, 162&amp;deg;53&amp;prime; E).&lt;/li&gt;&lt;li style=&quot;margin-bottom: 0.8em; padding-left: 0.5em; outline: 0px; font-size: 1.6em; background: 0px 0px;&quot;&gt;Ice transparency was the most variable parameter that affected benthic light dose, both spatially and between years. Patterns of lamina accrual corresponded to irradiance history, with laminae that were initiated in high transmission years thicker than those from low transmission years.&lt;/li&gt;&lt;li style=&quot;margin-bottom: 0.8em; padding-left: 0.5em; outline: 0px; font-size: 1.6em; background: 0px 0px;&quot;&gt;A shading experiment confirmed that accrual of lamina thickness, calcite precipitation and ash-free dry mass were determined by irradiance, but photosynthetic biomass and phototrophic species composition were less affected.&lt;/li&gt;&lt;li style=&quot;margin-bottom: 0.8em; padding-left: 0.5em; outline: 0px; font-size: 1.6em; background: 0px 0px;&quot;&gt;Buried laminae decomposed only slowly over time, with potentially viable phototrophs many laminae down into the microbial mat. Decay rate increased only slightly with shading.&lt;/li&gt;&lt;li style=&quot;margin-bottom: 0.8em; padding-left: 0.5em; outline: 0px; font-size: 1.6em; background: 0px 0px;&quot;&gt;We conclude that the microbial mats in Lake Hoare are characterised by remarkable stability, with slow accumulation rates and turnover of biomass over time. Photosynthetic biomass and species composition appeared to be stable across long time periods, with interannual variation in lamination pattern due to differential accumulation of extracellular polysaccharide and representing the visible expression of annual growth conditions.&lt;/li&gt;&lt;/ol&gt;</style></abstract><issue><style face="normal" font="default" size="100%">4</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%">Jungblut, Anne D.</style></author><author><style face="normal" font="default" size="100%">Ian Hawes</style></author><author><style face="normal" font="default" size="100%">Mackey, Tyler J.</style></author><author><style face="normal" font="default" size="100%">Krusor, Megan</style></author><author><style face="normal" font="default" size="100%">Peter T. Doran</style></author><author><style face="normal" font="default" size="100%">Sumner, Dawn Y.</style></author><author><style face="normal" font="default" size="100%">Eisen, Jonathan A.</style></author><author><style face="normal" font="default" size="100%">Hillman, Colin</style></author><author><style face="normal" font="default" size="100%">Goroncy, Alexander K.</style></author></authors><secondary-authors><author><style face="normal" font="default" size="100%">Stams, A. J.</style></author></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Microbial Mat Communities along an Oxygen Gradient in a Perennially Ice-Covered Antarctic Lake</style></title><secondary-title><style face="normal" font="default" size="100%">Applied and Environmental Microbiology</style></secondary-title><short-title><style face="normal" font="default" size="100%">Appl. Environ. Microbiol.</style></short-title></titles><dates><year><style  face="normal" font="default" size="100%">2016</style></year><pub-dates><date><style  face="normal" font="default" size="100%">01/2016</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://aem.asm.org/lookup/doi/10.1128/AEM.02699-15</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">82</style></volume><pages><style face="normal" font="default" size="100%">620 - 630</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><issue><style face="normal" font="default" size="100%">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%">Sumner, Dawn Y.</style></author><author><style face="normal" font="default" size="100%">Ian Hawes</style></author><author><style face="normal" font="default" size="100%">Mackey, Tyler J.</style></author><author><style face="normal" font="default" size="100%">Jungblut, Anne D.</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%">Antarctic microbial mats: A modern analog for Archean lacustrine oxygen oases</style></title><secondary-title><style face="normal" font="default" size="100%">Geology</style></secondary-title><short-title><style face="normal" font="default" size="100%">Geology</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%">10/2015</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://geology.gsapubs.org/lookup/doi/10.1130/G36966.1</style></url></web-urls></urls><pages><style face="normal" font="default" size="100%">G36966.1</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;div class=&quot;page&quot; title=&quot;Page 1&quot;&gt;&lt;div class=&quot;section&quot;&gt;&lt;div class=&quot;layoutArea&quot;&gt;&lt;div class=&quot;column&quot;&gt;&lt;p&gt;&lt;span style=&quot;font-size: 9.000000pt; font-family: 'Times'; font-weight: 700&quot;&gt;The evolution of oxygenic photosynthesis was the most important geochemical event in &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span style=&quot;font-size: 9.000000pt; font-family: 'Times'; font-weight: 700&quot;&gt;Earth history, causing the Great Oxidation Event (GOE) ~2.4 b.y. ago. However, evidence is mixed as to whether O&lt;/span&gt;&lt;span style=&quot;font-size: 5.000000pt; font-family: 'Times'; font-weight: 700; vertical-align: -3.000000pt&quot;&gt;2 &lt;/span&gt;&lt;span style=&quot;font-size: 9.000000pt; font-family: 'Times'; font-weight: 700&quot;&gt;production occurred locally as much as 2.8 b.y. ago, creating O&lt;/span&gt;&lt;span style=&quot;font-size: 5.000000pt; font-family: 'Times'; font-weight: 700; vertical-align: -3.000000pt&quot;&gt;2 &lt;/span&gt;&lt;span style=&quot;font-size: 9.000000pt; font-family: 'Times'; font-weight: 700&quot;&gt;oases, or initiated just prior to the GOE. The biogeochemical dynamics of possible O&lt;/span&gt;&lt;span style=&quot;font-size: 5.000000pt; font-family: 'Times'; font-weight: 700; vertical-align: -3.000000pt&quot;&gt;2 &lt;/span&gt;&lt;span style=&quot;font-size: 9.000000pt; font-family: 'Times'; font-weight: 700&quot;&gt;oases have been poorly constrained due to the absence of modern analogs. However, cyanobacteria in microbial mats in a perennially anoxic region of Lake Fryxell, Antarctica, create a 1&amp;ndash;2 mm O&lt;/span&gt;&lt;span style=&quot;font-size: 5.000000pt; font-family: 'Times'; font-weight: 700; vertical-align: -3.000000pt&quot;&gt;2&lt;/span&gt;&lt;span style=&quot;font-size: 9.000000pt; font-family: 'Times'; font-weight: 700&quot;&gt;-containing layer in the upper mat during summer, providing the first known modern analog for formation of benthic O&lt;/span&gt;&lt;span style=&quot;font-size: 5.000000pt; font-family: 'Times'; font-weight: 700; vertical-align: -3.000000pt&quot;&gt;2 &lt;/span&gt;&lt;span style=&quot;font-size: 9.000000pt; font-family: 'Times'; font-weight: 700&quot;&gt;oases. In Lake Fryxell, benthic cyanobacteria are present below the oxycline in the lake. Mat photosynthesis rates were slow due to low photon flux rate (1&amp;ndash;2 μmol m&lt;/span&gt;&lt;span style=&quot;font-size: 5.000000pt; font-family: 'Symbol'; vertical-align: 3.000000pt&quot;&gt;-&lt;/span&gt;&lt;span style=&quot;font-size: 5.000000pt; font-family: 'Times'; font-weight: 700; vertical-align: 3.000000pt&quot;&gt;2 &lt;/span&gt;&lt;span style=&quot;font-size: 9.000000pt; font-family: 'Times'; font-weight: 700&quot;&gt;s&lt;/span&gt;&lt;span style=&quot;font-size: 5.000000pt; font-family: 'Symbol'; vertical-align: 3.000000pt&quot;&gt;-&lt;/span&gt;&lt;span style=&quot;font-size: 5.000000pt; font-family: 'Times'; font-weight: 700; vertical-align: 3.000000pt&quot;&gt;1&lt;/span&gt;&lt;span style=&quot;font-size: 9.000000pt; font-family: 'Times'; font-weight: 700&quot;&gt;) under thick ice cover, but photosynthetic O&lt;/span&gt;&lt;span style=&quot;font-size: 5.000000pt; font-family: 'Times'; font-weight: 700; vertical-align: -3.000000pt&quot;&gt;2 &lt;/span&gt;&lt;span style=&quot;font-size: 9.000000pt; font-family: 'Times'; font-weight: 700&quot;&gt;production was sufficient to sustain up to 50 μmol O&lt;/span&gt;&lt;span style=&quot;font-size: 5.000000pt; font-family: 'Times'; font-weight: 700; vertical-align: -3.000000pt&quot;&gt;2 &lt;/span&gt;&lt;span style=&quot;font-size: 9.000000pt; font-family: 'Times'; font-weight: 700&quot;&gt;L&lt;/span&gt;&lt;span style=&quot;font-size: 5.000000pt; font-family: 'Symbol'; vertical-align: 3.000000pt&quot;&gt;-&lt;/span&gt;&lt;span style=&quot;font-size: 5.000000pt; font-family: 'Times'; font-weight: 700; vertical-align: 3.000000pt&quot;&gt;1&lt;/span&gt;&lt;span style=&quot;font-size: 9.000000pt; font-family: 'Times'; font-weight: 700&quot;&gt;, sandwiched between anoxic overlying water and anoxic sedi- ments. We hypothesize that Archean cyanobacteria could have similarly created O&lt;/span&gt;&lt;span style=&quot;font-size: 5.000000pt; font-family: 'Times'; font-weight: 700; vertical-align: -3.000000pt&quot;&gt;2 &lt;/span&gt;&lt;span style=&quot;font-size: 9.000000pt; font-family: 'Times'; font-weight: 700&quot;&gt;oases in benthic mats prior to the GOE. Analogous mats may have been at least partly responsible for geological evidence of oxidative weathering prior to the GOE, and habitats such as Lake Fryxell provide natural laboratories where the impact of benthic O&lt;/span&gt;&lt;span style=&quot;font-size: 5.000000pt; font-family: 'Times'; font-weight: 700; vertical-align: -3.000000pt&quot;&gt;2 &lt;/span&gt;&lt;span style=&quot;font-size: 9.000000pt; font-family: 'Times'; font-weight: 700&quot;&gt;oases on biogeochemical signatures can be investigated.&amp;nbsp;&lt;/span&gt;&lt;/p&gt;&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;p&gt;&amp;nbsp;&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%">Zhang, L.</style></author><author><style face="normal" font="default" size="100%">Jungblut, Anne D.</style></author><author><style face="normal" font="default" size="100%">Ian Hawes</style></author><author><style face="normal" font="default" size="100%">Dale T. Andersen</style></author><author><style face="normal" font="default" size="100%">Sumner, Dawn Y.</style></author><author><style face="normal" font="default" size="100%">Mackey, Tyler J.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Cyanobacterial diversity in benthic mats of the McMurdo Dry Valley lakes, Antarctica</style></title><secondary-title><style face="normal" font="default" size="100%">Polar Biology</style></secondary-title><short-title><style face="normal" font="default" size="100%">Polar Biol</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%">01/2015</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://link.springer.com/10.1007/s00300-015-1669-0http://link.springer.com/content/pdf/10.1007/s00300-015-1669-0</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">38</style></volume><pages><style face="normal" font="default" size="100%">1097 - 1110</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;div&gt;Perennially ice-covered, meromictic lakes in&amp;nbsp;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;the McMurdo Dry Valleys, Antarctica, are useful models to&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;study the relationship between cyanobacterial and environmental&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;variables. They have rich benthic cyanobacterial&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;mat accumulations and stable stratification of physical and&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;chemical conditions. Here, we evaluated cyanobacteria&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;from benthic mats from multiple depths in three geographically&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;separated ice-covered lakes, Lakes Vanda,&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;Hoare and Joyce, using 16S rRNA gene clone libraries. We&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;identified 19 ribotypes, mostly Oscillatoriales and several&lt;/span&gt;&lt;/div&gt;&lt;div&gt;Chroococcales, as well as potentially novel cyanobacterial&amp;nbsp;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;ribotypes. The majority of ribotype diversity was shared&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;between lakes, and only a weak relationship between ribotype&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;community structure and environmental variables&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;was evident. Multivariate analysis of all lake&amp;ndash;depth combinations&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;implied that photosynthetically active radiation,&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;dissolved reactive phosphorus and conductivity were&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;potentially important for shaping benthic communities in&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;McMurdo Dry Valley lakes. Cyanobacterial-specific pigment&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;signature analysis by high-performance liquid chromatography&lt;/span&gt;&lt;/div&gt;&lt;div&gt;showed that the cyanobacterial communities&amp;nbsp;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;responded to light conditions similarly, irrespective of&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;community composition. The results imply a capability&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;within a suite of cyanobacteria to colonise, adapt and grow&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;across broad environmental ranges and geographic space,&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;and such adaptability may provide a high degree of community&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;resistance and resilience to future climate-driven&amp;nbsp;&lt;/span&gt;&lt;span style=&quot;font-size: 0.923em; line-height: 1.5em;&quot;&gt;environmental change in Antarctic terrestrial aquatic&lt;/span&gt;&lt;/div&gt;&lt;div&gt;ecosystems.&lt;/div&gt;</style></abstract><issue><style face="normal" font="default" size="100%">8</style></issue></record></records></xml>