Microbial diversity of extant stromatolites in the hypersaline marine environment of Shark Bay, Australia

Authors

  • Brendan P. Burns,

    1. School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, 2052, Australia.
    Search for more papers by this author
  • Falicia Goh,

    1. School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, 2052, Australia.
    Search for more papers by this author
  • Michelle Allen,

    1. School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, 2052, Australia.
    2. Department of Earth, Planetary and Atmospheric Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
    Search for more papers by this author
  • Brett A. Neilan

    Corresponding author
    1. School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, 2052, Australia.
    Search for more papers by this author

*E-mail b.neilan@unsw.edu.au; Tel. (+61) 2 9385 3235; Fax (+61) 2 9385 1591.

Summary

Stromatolites have been present on Earth, at various levels of distribution and diversity, for more than 3 billion years. Today, the best examples of stromatolites forming in hypersaline marine environments are in Hamelin Pool at Shark Bay, Western Australia. Despite their evolutionary significance, little is known about their associated microbial communities. Using a polyphasic approach of culture-dependent and culture-independent methods, we report the discovery of a wide range of microorganisms associated with these biosedimentary structures. There are no comparable reports combining these methodologies in the survey of cyanobacteria, bacteria, and archaea in marine stromatolites. The community was characterized by organisms of the cyanobacterial genera Synechococcus, Xenococcus, Microcoleus, Leptolyngbya, Plectonema, Symploca, Cyanothece, Pleurocapsa and Nostoc. We also report the discovery of potentially free-living Prochloron. The other eubacterial isolates and clones clustered into seven phylogenetic groups: OP9, OP10, Marine A group, Proteobacteria, Low G+C Gram-positive, Planctomycetes and Acidobacteria. We also demonstrate the presence of sequences corresponding to members of halophilic archaea of the divisions Euryarchaeota and Crenarchaeota and methanogenic archaea of the order Methanosarcinales. This is the first report of such archaeal diversity from this environment. This study provides a better understanding of the microbial community associated with these living rocks.

Ancillary