title: Methane-consuming archaea revealed by directly coupled isotopic and phylogenetic analysis.
abstract: 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 the Methanosarcinales were all highly depleted in 13C (to values of -96 per thousand). This depletion indicates assimilation of isotopically light methane into specific archaeal cells. Additional microbial species apparently use other carbon sources, as indicated by significantly higher 13C/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.
authors.affiliation: Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA.
authors.forename: V J
authors.initials: VJ
authors.lastname: Orphan
authors.forename: C H
authors.initials: CH
authors.lastname: House
authors.forename: K U
authors.initials: KU
authors.lastname: Hinrichs
authors.forename: K D
authors.initials: KD
authors.lastname: McKeegan
authors.forename: E F
authors.initials: EF
authors.lastname: DeLong
mesh_terms: D000693:Anaerobiosis; D002247:Carbon Isotopes / Q000032:analysis; D020564:Deltaproteobacteria / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D019015:Geologic Sediments / Q000382:microbiology*; D017404:In Situ Hybridization, Fluorescence; D008055:Lipids / Q000032:analysis; D008697:Methane / Q000378:metabolism*; D019640:Methanosarcinales / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D009792:Oceans and Seas; D015345:Oligonucleotide Probes; D010084:Oxidation-Reduction; D010802:Phylogeny; D019642:RNA, Archaeal / Q000235:genetics; D012329:RNA, Bacterial / Q000235:genetics; D012335:RNA, Ribosomal / Q000235:genetics; D018629:Spectrometry, Mass, Secondary Ion; D013431:Sulfates / Q000378:metabolism
chemical_list: D002247:Carbon Isotopes; D008055:Lipids; D015345:Oligonucleotide Probes; D019642:RNA, Archaeal; D012329:RNA, Bacterial; D012335:RNA, Ribosomal; D013431:Sulfates; D008697:Methane