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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Anna Rusznyak</dc:contributor>
  <dc:contributor>Denise M. Akob</dc:contributor>
  <dc:contributor>Isabel Schulze</dc:contributor>
  <dc:contributor>Sebastian Opitz</dc:contributor>
  <dc:contributor>Kai Uwe Totsche</dc:contributor>
  <dc:contributor>Kirsten Küsel</dc:contributor>
  <dc:creator>Martina Herrmann</dc:creator>
  <dc:date>2015</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;The traditional view of the dependency of subsurface environments on surface-derived allochthonous carbon inputs is challenged by increasing evidence for the role of lithoautotrophy in aquifer carbon flow. We linked information on autotrophy (Calvin-Benson-Bassham cycle) with that from total microbial community analysis in groundwater at two superimposed&amp;mdash;upper and lower&amp;mdash;limestone groundwater reservoirs (aquifers). Quantitative PCR revealed that up to 17% of the microbial population had the genetic potential to fix CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;via the Calvin cycle, with abundances of&amp;nbsp;&lt;/span&gt;&lt;i&gt;cbbM&lt;/i&gt;&lt;span&gt;&amp;nbsp;and&amp;nbsp;&lt;/span&gt;&lt;i&gt;cbbL&lt;/i&gt;&lt;span&gt;&amp;nbsp;genes, encoding RubisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) forms I and II, ranging from 1.14 &amp;times; 10&lt;/span&gt;&lt;sup&gt;3&lt;/sup&gt;&lt;span&gt;&amp;nbsp;to 6 &amp;times; 10&lt;/span&gt;&lt;sup&gt;6&lt;/sup&gt;&lt;span&gt;&amp;nbsp;genes liter&lt;/span&gt;&lt;sup&gt;&amp;minus;1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;over a 2-year period. The structure of the active microbial communities based on 16S rRNA transcripts differed between the two aquifers, with a larger fraction of heterotrophic, facultative anaerobic, soil-related groups in the oxygen-deficient upper aquifer. Most identified CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;-assimilating phylogenetic groups appeared to be involved in the oxidation of sulfur or nitrogen compounds and harbored both RubisCO forms I and II, allowing efficient CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;fixation in environments with strong oxygen and CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;fluctuations. The genera&amp;nbsp;&lt;/span&gt;&lt;span id="named-content-1" class="named-content genus-species"&gt;Sulfuricella&lt;/span&gt;&lt;span&gt;and&amp;nbsp;&lt;/span&gt;&lt;span id="named-content-2" class="named-content genus-species"&gt;Nitrosomonas&lt;/span&gt;&lt;span&gt;&amp;nbsp;were represented by read fractions of up to 78 and 33%, respectively, within the&amp;nbsp;&lt;/span&gt;&lt;i&gt;cbbM&lt;/i&gt;&lt;span&gt;&amp;nbsp;and&amp;nbsp;&lt;/span&gt;&lt;i&gt;cbbL&lt;/i&gt;&lt;span&gt;&amp;nbsp;transcript pool and accounted for 5.6 and 3.8% of 16S rRNA sequence reads, respectively, in the lower aquifer. Our results indicate that a large fraction of bacteria in pristine limestone aquifers has the genetic potential for autotrophic CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;fixation, with energy most likely provided by the oxidation of reduced sulfur and nitrogen compounds.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1128/AEM.03269-14</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>American Society for Microbiology</dc:publisher>
  <dc:title>Large fractions of CO&lt;sub&gt;2&lt;/sub&gt;-fixing microorganisms in pristine limestone aquifers appear to be involved in the oxidation of reduced sulfur and nitrogen compounds</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>