Methanotrophic bacteria in warm geothermal spring sediments identified using stable‐isotope probing. Issue 1 (22nd July 2014)

• Record Type: Journal Article
• Authors: Sharp, Christine E.; Martínez‐Lorenzo, Azucena; Brady, Allyson L.; Grasby, Stephen E.; Dunfield, Peter F.
• Is Part Of: FEMS microbiology ecology. Volume 90:Issue 1(2014)
• Page Start: 92
• Page End: 102
• Publication Date: 2014-07-22
• Subjects: Microbial ecology -- Periodicals; Microbiology -- Periodicals; 579.17
• DOI: 10.1111/1574-6941.12375
• Languages: English
• ISSNs: 0168-6496

Abstract

<abstract abstract-type="main" id="fem12375-abs-0001"> <title>Abstract</title> <p>We investigated methanotrophic bacteria in sediments of several warm geothermal springs ranging in temperature from 22 to 45 °C. Methane oxidation was measured at potential rates up to 141 μmol CH<sub>4</sub> d<sup>−1</sup> g<sup>−1</sup> sediment. Active methanotrophs were identified using <sup>13</sup>CH<sub>4</sub> stable‐isotope probing (SIP) incubations performed at close to <italic>in situ</italic> temperatures for each site. Quantitative (q) PCR of <italic>pmoA</italic> genes identified the position of the heavy (<sup>13</sup>C‐labelled) DNA fractions in density gradients, and 16S rRNA gene pyrotag sequencing of the heavy fractions was performed to identify the active methanotrophs. Methanotroph communities identified in heavy fractions of all samples were predominated by species similar (≥ 95% 16S rRNA gene identities) to previously characterized <italic>Gammaproteobacteria</italic> and <italic>Alphaproteobacteria</italic> methanotrophs. Among the five hottest samples (45 °C), members of the <italic>Gammaproteobacteria</italic> genus <italic>Methylocaldum</italic> dominated in two cases, while three others were dominated by an OTU closely related (96.8% similarity) to the <italic>Alphaproteobacteria</italic> genus <italic>Methylocapsa</italic>. These results suggest that diverse methanotroph groups are adapted to warm environments, including the <italic>Methylocapsa‐Methylocella‐Methyloferula</italic> group, which has previously only been detected in cooler sites.</p> </abstract>