Get access

Unveiling microbial life in the new deep-sea hypersaline Lake Thetis. Part II: a metagenomic study

Authors

  • Manuel Ferrer,

    Corresponding author
    1. CSIC, Institute of Catalysis, 28049 Madrid, Spain
    Search for more papers by this author
    • These authors contributed equally to this work.

  • Johannes Werner,

    1. Max Planck Institute for Marine Microbiology (MPI-MM), 28359 Bremen, Germany
    Search for more papers by this author
    • These authors contributed equally to this work.

  • Tatyana N. Chernikova,

    1. School of Biological Sciences, Bangor University, Bangor, Gwynedd, UK
    Search for more papers by this author
  • Rafael Bargiela,

    1. CSIC, Institute of Catalysis, 28049 Madrid, Spain
    Search for more papers by this author
  • Lucía Fernández,

    1. CSIC, Institute of Catalysis, 28049 Madrid, Spain
    Search for more papers by this author
  • Violetta La Cono,

    1. Laboratory of Marine Molecular Microbiology, Institute for Coastal Marine Environment (IAMC), CNR, Messina, Italy
    Search for more papers by this author
  • Jost Waldmann,

    1. Max Planck Institute for Marine Microbiology (MPI-MM), 28359 Bremen, Germany
    Search for more papers by this author
  • Hanno Teeling,

    1. Max Planck Institute for Marine Microbiology (MPI-MM), 28359 Bremen, Germany
    Search for more papers by this author
    • Principal investigators.The Whole Genome Shotgun project has been deposited at DDBJ/EMBL/GenBank under the accession AGBJ00000000 (Interface) and AGBK00000000 (Brine). The version described in this paper is the first version, xxxx01000000. Nucleotide sequences will be deposited to the GenBank.

  • Olga V. Golyshina,

    1. School of Biological Sciences, Bangor University, Bangor, Gwynedd, UK
    Search for more papers by this author
    • Principal investigators.The Whole Genome Shotgun project has been deposited at DDBJ/EMBL/GenBank under the accession AGBJ00000000 (Interface) and AGBK00000000 (Brine). The version described in this paper is the first version, xxxx01000000. Nucleotide sequences will be deposited to the GenBank.

  • Frank Oliver Glöckner,

    1. Max Planck Institute for Marine Microbiology (MPI-MM), 28359 Bremen, Germany
    2. Jacobs University Bremen gGmbH, Campus Ring 1, 28759 Bremen, Germany
    Search for more papers by this author
    • Principal investigators.The Whole Genome Shotgun project has been deposited at DDBJ/EMBL/GenBank under the accession AGBJ00000000 (Interface) and AGBK00000000 (Brine). The version described in this paper is the first version, xxxx01000000. Nucleotide sequences will be deposited to the GenBank.

  • Michail M. Yakimov,

    Corresponding author
    1. Laboratory of Marine Molecular Microbiology, Institute for Coastal Marine Environment (IAMC), CNR, Messina, Italy
    Search for more papers by this author
    • These authors contributed equally to this work.

    • Principal investigators.The Whole Genome Shotgun project has been deposited at DDBJ/EMBL/GenBank under the accession AGBJ00000000 (Interface) and AGBK00000000 (Brine). The version described in this paper is the first version, xxxx01000000. Nucleotide sequences will be deposited to the GenBank.

  • Peter N. Golyshin,

    Corresponding author
    1. School of Biological Sciences, Bangor University, Bangor, Gwynedd, UK
    Search for more papers by this author
    • These authors contributed equally to this work.

    • Principal investigators.The Whole Genome Shotgun project has been deposited at DDBJ/EMBL/GenBank under the accession AGBJ00000000 (Interface) and AGBK00000000 (Brine). The version described in this paper is the first version, xxxx01000000. Nucleotide sequences will be deposited to the GenBank.

  • The MAMBA Scientific Consortium


E-mail mferrer@icp.csic.es; Tel. (+34) 91 585 4872; Fax (+34) 91 585 4760; E-mail michail.yakimov@iamc.cnr.it; Tel. (+39) (090) 669 003; Fax (+39) (090) 669 007; E-mail p.golyshin@bangor.ac.uk; Tel. (+44) 1248 38 3629; Fax (+44) 1248 38 2569.

Summary

So far only little is known about the microbial ecology of Mediterranean deep-sea hypersaline anoxic lakes (DHALs). These brine lakes were formed by evaporite dissolution/brine seeps and are important model environments to provide insights into possible metabolisms and distributions of microorganisms on the early Earth. Our study on the Lake Thetis, a new thalassohaline DHAL located South-East of the Medriff Corridor, has revealed microbial communities of contrasting compositions with a high number of novel prokaryotic candidate divisions. The major finding of our present work is co-occurrence of at least three autotrophic carbon dioxide fixation pathways in the brine–seawater interface that are likely fuelled by an active ramified sulphur cycle. Genes for the reductive acetyl-CoA and reductive TCA pathways were also found in the brine suggesting that these pathways are operational even at extremely elevated salinities and that autotrophy is more important in hypersaline environments than previously assumed. Surprisingly, genes coding for RuBisCo were found in the highly reduced brine. Three types of sulphide oxidation pathways were found in the interface. The first involves a multienzyme Sox complex catalysing the complete oxidation of reduced sulphur compounds to sulphate, the second type recruits SQR sulphide:quinone reductase for oxidation of sulphide to elemental sulphur, which, in the presence of sulphide, could further be reduced by polysulphide reductases in the third pathway. The presence of the latter two allows a maximal energy yield from the oxidation of sulphide and at the same time prevents the acidification and the accumulation of S0 deposits. Amino acid composition analysis of deduced proteins revealed a significant overrepresentation of acidic residues in the brine compared with the interface. This trait is typical for halophilic organisms as an adaptation to the brine's extreme hypersalinity. This work presents the first metagenomic survey of the microbial communities of the recently discovered Lake Thetis whose brine constitutes one of saltiest water bodies ever reported.

Ancillary