title: Artificial electron acceptors decouple archaeal methane oxidation from sulfate reduction.
abstract: The oxidation of methane with sulfate is an important microbial metabolism in the global carbon cycle. In marine methane seeps, this process is mediated by consortia of anaerobic methanotrophic archaea (ANME) that live in syntrophy with sulfate-reducing bacteria (SRB). The underlying interdependencies within this uncultured symbiotic partnership are poorly understood. We used a combination of rate measurements and single-cell stable isotope probing to demonstrate that ANME in deep-sea sediments can be catabolically and anabolically decoupled from their syntrophic SRB partners using soluble artificial oxidants. The ANME still sustain high rates of methane oxidation in the absence of sulfate as the terminal oxidant, lending support to the hypothesis that interspecies extracellular electron transfer is the syntrophic mechanism for the anaerobic oxidation of methane.
authors.affiliation: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Silvan
authors.initials: S
authors.lastname: Scheller
authors.affiliation: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Hang
authors.initials: H
authors.lastname: Yu
authors.affiliation: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Grayson L
authors.initials: GL
authors.lastname: Chadwick
authors.affiliation: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Shawn E
authors.initials: SE
authors.lastname: McGlynn
authors.affiliation: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Victoria J
authors.initials: VJ
authors.lastname: Orphan
mesh_terms: D000693:Anaerobiosis; D057486:Carbon Cycle; D004579:Electron Transport; D019015:Geologic Sediments / Q000382:microbiology; D008697:Methane / Q000378:metabolism*; D019640:Methanosarcinales / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010802:Phylogeny; D019642:RNA, Archaeal / Q000145:classification / Q000235:genetics; D012623:Seawater / Q000382:microbiology; D013431:Sulfates / Q000378:metabolism*; D016999:Sulfur-Reducing Bacteria / Q000378:metabolism
chemical_list: D019642:RNA, Archaeal; D013431:Sulfates; D008697:Methane