Nature 437, 543-546 (22 September 2005) | doi:10.1038/nature03911; Received 21 March 2005; Accepted 8 June 2005

Isolation of an autotrophic ammonia-oxidizing marine archaeon

Martin Könneke1,4,3, Anne E. Bernhard1,4,3, José R. de la Torre1,4, Christopher B. Walker1, John B. Waterbury2 & David A. Stahl1

  1. Department of Civil and Environmental Engineering, University of Washington, Seattle, Washington 98195, USA
  2. Woods Hole Oceanographic Institute, Woods Hole, Massachusetts 02543, USA
  3. †Present addresses: Institut für Chemie und Biologie des Meeres, Universität Oldenburg, Oldenburg 26111, Germany (M.K.); Department of Biology, Connecticut College, New London, Connecticut 06320, USA (A.E.B.)
  4. *These authors contributed equally to this work

Correspondence to: David A. Stahl1 Correspondence and requests for materials should be addressed to D.A.S. (Email: dastahl@u.washington.edu). The sequences described in this manuscript have been deposited in GenBank under accession numbers DQ085097 to DQ085105.

For years, microbiologists characterized the Archaea as obligate extremophiles that thrive in environments too harsh for other organisms. The limited physiological diversity among cultivated Archaea suggested that these organisms were metabolically constrained to a few environmental niches. For instance, all Crenarchaeota that are currently cultivated are sulphur-metabolizing thermophiles1. However, landmark studies using cultivation-independent methods uncovered vast numbers of Crenarchaeota in cold oxic ocean waters2, 3. Subsequent molecular surveys demonstrated the ubiquity of these low-temperature Crenarchaeota in aquatic and terrestrial environments4. The numerical dominance of marine Crenarchaeota—estimated at 1028 cells in the world's oceans5—suggests that they have a major role in global biogeochemical cycles. Indeed, isotopic analyses of marine crenarchaeal lipids suggest that these planktonic Archaea fix inorganic carbon6. Here we report the isolation of a marine crenarchaeote that grows chemolithoautotrophically by aerobically oxidizing ammonia to nitrite—the first observation of nitrification in the Archaea. The autotrophic metabolism of this isolate, and its close phylogenetic relationship to environmental marine crenarchaeal sequences, suggests that nitrifying marine Crenarchaeota may be important to global carbon and nitrogen cycles.