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Metabolic variability in seafloor brines revealed by carbon and sulphur dynamics

Nature Geoscience volume 2, pages 349354 (2009) | Download Citation

  • An Erratum to this article was published on 21 May 2009


Brine fluids that upwell from deep, hot reservoirs below the sea bed supply the sea floor with energy-rich substrates and nutrients that are used by diverse microbial ecosystems. Contemporary hypersaline environments formed by brine seeps may provide insights into the metabolism and distribution of microorganisms on the early Earth1 or on extraterrestrial bodies2. Here we use geochemical and genetic analyses to characterize microbial community composition and metabolism in two seafloor brines in the Gulf of Mexico: an active mud volcano and a quiescent brine pool. Both brine environments are anoxic and hypersaline. However, rates of sulphate reduction and acetate production are much higher in the brine pool, whereas the mud volcano supports much higher rates of methane production. We find no evidence of anaerobic oxidation of methane, despite high methane fluxes at both sites. We conclude that the contrasting microbial community compositions and metabolisms are linked to differences in dissolved-organic-matter input from the deep subsurface and different fluid advection rates between the two sites.

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This research was supported by the US National Science Foundation Life in Extreme Environments and Microbial Observatories programs; the National Oceanographic and Atmospheric Administration National Undersea Research Program; the Department of Energy; the American Chemical Society Petroleum Research Fund; the Environmental Protection Agency; the NASA Astrobiology Institute; and the Deutsche Forschungsgemeinschaft. We thank members of the LExEn 2002 shipboard scientific party and the ship and submersible crews from Harbor Branch Oceanographic Institution for help collecting and processing samples; Mitch Sogin and the Bay Paul Center at the Marine Biological Laboratory for efficient sequencing support; Basil Blake for painting Fig. 1; and A. Boetius, N. Finke and B. Gilhooly for providing comments that improved this manuscript.

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    • Beth! N. Orcutt
    •  & Mark A. Lever

    Present addresses: University of Southern California, Los Angeles, California 90089, USA (B.N.O.); Center for Geomicrobiology, Biology Institute, Ny Munkegade 1540 DK-0800 Århus C, Denmark (M.A.L.)


  1. Department of Marine Sciences, University of Georgia, Athens, Georgia 30602-3636, USA

    • Samantha B. Joye
    • , Vladimir A. Samarkin
    • , Beth! N. Orcutt
    •  & Christof D. Meile
  2. Department of Physical and Environmental Sciences, Texas A&M University, Corpus Christi, Texas 78412, USA

    • Ian R. MacDonald
  3. Organic Geochemistry Group, MARUM Center for Marine Environmental Sciences & Department of Geosciences, University of Bremen, 28334 Bremen, Germany

    • Kai-Uwe Hinrichs
    •  & Marcus Elvert
  4. Department of Marine Sciences, University of North Carolina, Chapel Hill, North Carolina 27599, USA

    • Andreas P. Teske
    • , Karen G. Lloyd
    •  & Mark A. Lever
  5. School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332, USA

    • Joseph P. Montoya


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S.B.J., V.A.S., I.R.M. and J.P.M. conceived the experiment and carried it out; K.-U.H. and M.E. completed the carbon isotopic analyses; A.P.T., K.G.L., M.A.L. and B.N.O. completed the molecular biological analyses; C.D.M. completed the thermodynamic calculations; S.B.J. wrote the paper and all authors provided editorial comments.

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Correspondence to Samantha B. Joye or Beth! N. Orcutt or Mark A. Lever.

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