Identification and activity of acetate‐assimilating bacteria in diffuse fluids venting from two deep‐sea hydrothermal systems. Issue 3 (13th October 2014)

• Record Type: Journal Article
• Authors: Winkel, Matthias; Pjevac, Petra; Kleiner, Manuel; Littmann, Sten; Meyerdierks, Anke; Amann, Rudolf; Mußmann, Marc
• Is Part Of: FEMS microbiology ecology. Volume 90:Issue 3(2014)
• Page Start: 731
• Page End: 746
• Publication Date: 2014-10-13
• Subjects: Microbial ecology -- Periodicals; Microbiology -- Periodicals; 579.17
• DOI: 10.1111/1574-6941.12429
• Languages: English
• ISSNs: 0168-6496

Abstract

<abstract abstract-type="main" id="fem12429-abs-0001"> <title>Abstract</title> <p>Diffuse hydrothermal fluids often contain organic compounds such as hydrocarbons, lipids, and organic acids. Microorganisms consuming these compounds at hydrothermal sites are so far only known from cultivation‐dependent studies. To identify potential heterotrophs without prior cultivation, we combined microbial community analysis with short‐term incubations using <sup>13</sup>C‐labeled acetate at two distinct hydrothermal systems. We followed cell growth and assimilation of <sup>13</sup>C into single cells by nanoSIMS combined with fluorescence <italic>in situ</italic> hybridization (FISH). In 55 °C‐fluids from the Menez Gwen hydrothermal system/Mid‐Atlantic Ridge, a novel epsilonproteobacterial group accounted for nearly all assimilation of acetate, representing the first aerobic acetate‐consuming member of the <italic>Nautiliales</italic>. In contrast, <italic>Gammaproteobacteria</italic> dominated the <sup>13</sup>C‐acetate assimilation in incubations of 37 °C‐fluids from the back‐arc hydrothermal system in the Manus Basin/Papua New Guinea. Here, 16S rRNA gene sequences were mostly related to mesophilic <italic>Marinobacter</italic>, reflecting the high content of seawater in these fluids. The rapid growth of microorganisms upon acetate addition suggests that acetate consumers in diffuse fluids are copiotrophic opportunists, which quickly exploit their energy sources, whenever available under the spatially and temporally highly fluctuating conditions. Our data provide first insights into the heterotrophic microbial community, catalyzing an under‐investigated part of microbial carbon cycling at hydrothermal vents.</p> </abstract>