PT - JOURNAL ARTICLE AU - Orphan, Victoria J. AU - House, Christopher H. AU - Hinrichs, Kai-Uwe AU - McKeegan, Kevin D. AU - DeLong, Edward F. TI - Methane-Consuming Archaea Revealed by Directly Coupled Isotopic and Phylogenetic Analysis AID - 10.1126/science.1061338 DP - 2001 Jul 20 TA - Science PG - 484--487 VI - 293 IP - 5529 4099 - http://science.sciencemag.org/content/293/5529/484.short 4100 - http://science.sciencemag.org/content/293/5529/484.full SO - Science2001 Jul 20; 293 AB - Microorganisms living in anoxic marine sediments consume more than 80% of the methane produced in the world's oceans. In addition to single-species aggregates, consortia of metabolically interdependent bacteria and archaea are found in methane-rich sediments. A combination of fluorescence in situ hybridization and secondary ion mass spectrometry shows that cells belonging to one specific archaeal group associated with theMethanosarcinales were all highly depleted in13C (to values of –96‰). This depletion indicates assimilation of isotopically light methane into specific archaeal cells. Additional microbial species apparently use other carbon sources, as indicated by significantly higher13C/12C ratios in their cell carbon. Our results demonstrate the feasibility of simultaneous determination of the identity and the metabolic activity of naturally occurring microorganisms.