title: Zero-valent sulphur is a key intermediate in marine methane oxidation.
abstract: Emissions of methane, a potent greenhouse gas, from marine sediments are controlled by anaerobic oxidation of methane coupled primarily to sulphate reduction (AOM). Sulphate-coupled AOM is believed to be mediated by a consortium of methanotrophic archaea (ANME) and sulphate-reducing Deltaproteobacteria but the underlying mechanism has not yet been resolved. Here we show that zero-valent sulphur compounds (S(0)) are formed during AOM through a new pathway for dissimilatory sulphate reduction performed by the methanotrophic archaea. Hence, AOM might not be an obligate syntrophic process but may be carried out by the ANME alone. Furthermore, we show that the produced S(0)--in the form of disulphide--is disproportionated by the Deltaproteobacteria associated with the ANME. Our observations expand the diversity of known microbially mediated sulphur transformations and have significant implications for our understanding of the biogeochemical carbon and sulphur cycles.
authors.affiliation: Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Milucka
authors.forename: Timothy G
authors.initials: TG
authors.lastname: Ferdelman
authors.forename: Lubos
authors.initials: L
authors.lastname: Polerecky
authors.forename: Daniela
authors.initials: D
authors.lastname: Franzke
authors.forename: Gunter
authors.initials: G
authors.lastname: Wegener
authors.forename: Markus
authors.initials: M
authors.lastname: Schmid
authors.forename: Ingo
authors.initials: I
authors.lastname: Lieberwirth
authors.forename: Michael
authors.initials: M
authors.lastname: Wagner
authors.forename: Friedrich
authors.initials: F
authors.lastname: Widdel
authors.forename: Marcel M M
authors.initials: MM
authors.lastname: Kuypers
mesh_terms: D000693:Anaerobiosis; D059001:Aquatic Organisms / Q000378:metabolism*; D001105:Archaea / Q000378:metabolism*; D057486:Carbon Cycle; D002245:Carbon Dioxide / Q000378:metabolism; D020564:Deltaproteobacteria / Q000378:metabolism*; D004220:Disulfides / Q000378:metabolism; D019015:Geologic Sediments / Q000737:chemistry; D008697:Methane / Q000378:metabolism*; D008954:Models, Biological; D010084:Oxidation-Reduction; D013431:Sulfates / Q000378:metabolism; D013455:Sulfur / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D004220:Disulfides; D013431:Sulfates; D002245:Carbon Dioxide; D013455:Sulfur; D008697:Methane