Novel uncultured Epsilonproteobacteria dominate a filamentous sulphur mat from the 13°N hydrothermal vent field, East Pacific Rise

Authors

  • Hélène Moussard,

    1. Laboratoire de Microbiologie des Environnements Extrêmes, Centre National de la Recherche Scientifique, IFREMER, Université de Bretagne Occidentale, Institut Universitaire Européen de la Mer, Plouzané, France
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  • Erwan Corre,

    1. FR 2424, Station Biologique, Roscoff, France
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  • Marie-Anne Cambon-Bonavita,

    1. Laboratoire de Microbiologie des Environnements Extrêmes, Centre National de la Recherche Scientifique, IFREMER, Université de Bretagne Occidentale, Institut Universitaire Européen de la Mer, Plouzané, France
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  • Yves Fouquet,

    1. Département de Géosciences Marines, IFREMER Centre de Brest, Plouzané, France
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  • Christian Jeanthon

    1. Laboratoire de Microbiologie des Environnements Extrêmes, Centre National de la Recherche Scientifique, IFREMER, Université de Bretagne Occidentale, Institut Universitaire Européen de la Mer, Plouzané, France
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  • Editor: Michael Wagner

Correspondence: Christian Jeanthon, UMR 7144, Equipe Phytoplancton Océanique, Station Biologique, Place Georges Teissier, 29682 Roscoff Cedex, France. Tel.: +33 298 292 379; fax: +33 298 292 324; e-mail: jeanthon@sb-roscoff.fr

Abstract

Rapid growth of microbial sulphur mats have repeatedly been observed during oceanographic cruises to various deep-sea hydrothermal vent sites. The microorganisms involved in the mat formation have not been phylogenetically characterized, although the production of morphologically similar sulphur filaments by a Arcobacter strain coastal marine has been documented. An in situ collector deployed for 5 days at the 13°N deep-sea hydrothermal vent site on the East Pacific Rise (EPR) was rapidly colonized by a filamentous microbial mat. Microscopic and chemical analyses revealed that the mat consisted of a network of microorganisms embedded in a mucous sulphur-rich matrix. Molecular surveys based on 16S rRNA gene and aclB genes placed all the environmental clone sequences within the Epsilonproteobacteria. Although few 16S rRNA gene sequences were affiliated with that of cultured organisms, the majority was related to uncultured representatives of the Arcobacter group (≤95% sequence similarity). A probe designed to target all of the identified lineages hybridized with more than 95% of the mat community. Simultaneous hybridizations with the latter probe and a probe specific to Arcobacter spp. confirmed the numerical dominance of Arcobacter-like bacteria. This study provides the first example of the prevalence and ecological significance of free-living Arcobacter at deep-sea hydrothermal vents.

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