Microbial lipids reveal carbon assimilation patterns on hydrothermal sulfide chimneys. (7th July 2014)

• Record Type: Journal Article
• Authors: Reeves, Eoghan P.; Yoshinaga, Marcos Y.; Pjevac, Petra; Goldenstein, Nadine I.; Peplies, Jörg; Meyerdierks, Anke; Amann, Rudolf; Bach, Wolfgang; Hinrichs, Kai‐Uwe
• Is Part Of: Environmental microbiology. Volume 16:Number 11(2014:Nov.)
• Page Start: 3515
• Page End: 3532
• Publication Date: 2014-07-07
• Subjects: Microbial ecology -- Periodicals; Environmental Microbiology -- Periodicals; 579.17
• DOI: 10.1111/1462-2920.12525
• Languages: English
• ISSNs: 1462-2912

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>Sulfide 'chimneys' characteristic of seafloor hydrothermal venting are diverse microbial habitats. <sup>13</sup>C/<sup>12</sup>C ratios of microbial lipids have rarely been used to assess carbon assimilation pathways on these structures, despite complementing gene‐ and culture‐based approaches. Here, we integrate analyses of the diversity of intact polar lipids (IPL) and their side‐chain δ<sup>13</sup>C values (δ<sup>13</sup>C<sub>lipid</sub>) with 16S rRNA gene‐based phylogeny to examine microbial carbon flow on active and inactive sulfide structures from the Manus Basin. Surficial crusts of active structures, dominated by <italic>E</italic><italic>psilonproteobacteria</italic>, yield bacterial δ<sup>13</sup>C<sub>lipid</sub> values higher than biomass δ<sup>13</sup>C (total organic carbon), implicating autotrophy via the reverse tricarboxylic acid cycle. Our data also suggest δ<sup>13</sup>C<sub>lipid</sub> values vary on individual active structures without accompanying microbial diversity changes. Temperature and/or dissolved substrate effects – likely relating to variable advective–diffusive fluxes to chimney exteriors – may be responsible for differing <sup>13</sup>C fractionation during assimilation. In an inactive structure, δ<sup>13</sup>C<sub>lipid</sub> values lower than biomass δ<sup>13</sup>C and a distinctive IPL and 16S rRNA gene diversity suggest a shift to a more diverse community and an alternate carbon assimilation pathway after venting ceases. We discuss here the potential of IPL and δ<sup>13</sup>C<sub>lipid</sub> analyses to elucidate carbon flow in hydrothermal structures when combined with other molecular tools.</p> </abstract>