An obligately photosynthetic bacterial anaerobe from a deep-sea hydrothermal vent

doi:10.1073/pnas.0503674102

An obligately photosynthetic bacterial anaerobe from a deep-sea hydrothermal vent

^*Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada V6T 1Z3; ^‡Department Biology I, University of Munich, 80638 München, Germany; ^§Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85069; ^¶Institute of Marine Science, University of Alaska Fairbanks, Fairbanks, AK 99775; ^∥Biology Department, College of William and Mary, Williamsburg, VA 23187; and ^**Bermuda Biological Station for Research, St. George's GE 01, Bermuda

Communicated by Bob B. Buchanan, University of California, Berkeley, CA, May 3, 2005 (received for review March 3, 2005)

Abstract

The abundance of life on Earth is almost entirely due to biological photosynthesis, which depends on light energy. The source of light in natural habitats has heretofore been thought to be the sun, thus restricting photosynthesis to solar photic environments on the surface of the Earth. If photosynthesis could take place in geothermally illuminated environments, it would increase the diversity of photosynthetic habitats both on Earth and on other worlds that have been proposed to possibly harbor life. Green sulfur bacteria are anaerobes that require light for growth by the oxidation of sulfur compounds to reduce CO₂ to organic carbon, and are capable of photosynthetic growth at extremely low light intensities. We describe the isolation and cultivation of a previously unknown green sulfur bacterial species from a deep-sea hydrothermal vent, where the only source of light is geothermal radiation that includes wavelengths absorbed by photosynthetic pigments of this organism.

Footnotes

↵ † To whom correspondence should be addressed. E-mail: jbeatty{at}interchange.ubc.ca.
Author contributions: J.T.B., J.O., R.E.B., C.L.V.D., and F.G.P. designed research; J.T.B., J.O., M.T.L., A.K.M., A.S.L., R.E.B., C.L.V.D., T.A.M., and F.G.P. performed research; J.T.B. and R.E.B. analyzed data; and J.T.B., R.E.B., and C.L.V.D. wrote the paper.
Abbreviation: BChl, bacteriochlorophyll.
Data deposition: The sequences reported in this paper have been deposited in the GenBank database [accession nos. AY627684 (FMO) and AY627756 (16S rRNA)].