A hydrogen-based subsurface microbial community dominated by methanogens

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The search for extraterrestrial life may be facilitated if ecosystems can be found on Earth that exist under conditions analogous to those present on other planets or moons. It has been proposed, on the basis of geochemical and thermodynamic considerations, that geologically derived hydrogen might support subsurface microbial communities on Mars and Europa in which methanogens form the base of the ecosystem1-5. Here we describe a unique subsurface microbial community in which hydrogen-consuming, methane-producing Archaea far outnumber the Bacteria. More than 90% of the 16s ribosomal DNA sequences recovered from hydrothermal waters circulating through deeply buried igneous rocks in Idaho are related to hydrogen-using methanogenic microorganisms. Geochemical characterization indicates that geothermal hydrogen, not organic carbon, is the primary energy source for this methanogen-dominated microbial community. These results demonstrate that hydrogen-based methanogenic communities do occur in Earth's subsurface, providing an analogue for possible subsurface microbial ecosystems on other planets.
Publication type Article
Publication Subtype Journal Article
Title A hydrogen-based subsurface microbial community dominated by methanogens
Series title Nature
DOI 10.1038/415312a
Volume 415
Issue 6869
Year Published 2002
Language English
Publisher Springer
Contributing office(s) Toxic Substances Hydrology Program
Description 4 p.
First page 312
Last page 315
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