title: Evidence of active methanogen communities in shallow sediments of the sonora margin cold seeps.
abstract: In the Sonora Margin cold seep ecosystems (Gulf of California), sediments underlying microbial mats harbor high biogenic methane concentrations, fueling various microbial communities, such as abundant lineages of anaerobic methanotrophs (ANME). However, the biodiversity, distribution, and metabolism of the microorganisms producing this methane remain poorly understood. In this study, measurements of methanogenesis using radiolabeled dimethylamine, bicarbonate, and acetate showed that biogenic methane production in these sediments was mainly dominated by methylotrophic methanogenesis, while the proportion of autotrophic methanogenesis increased with depth. Congruently, methane production and methanogenic Archaea were detected in culture enrichments amended with trimethylamine and bicarbonate. Analyses of denaturing gradient gel electrophoresis (DGGE) fingerprinting and reverse-transcribed PCR-amplified 16S rRNA sequences retrieved from these enrichments revealed the presence of active methylotrophic Methanococcoides burtonii relatives and several new autotrophic Methanogenium lineages, confirming the cooccurrence of Methanosarcinales and Methanomicrobiales methanogens with abundant ANME populations in the sediments of the Sonora Margin cold seeps.
authors.affiliation: Ifremer, Laboratoire de Microbiologie des Environnements Extrêmes, UMR6197, Technopôle Brest Iroise, Plouzané, France Université de Bretagne Occidentale, Laboratoire de Microbiologie des Environnements Extrêmes, UMR6197, Technopôle Brest Iroise, Plouzané, France CNRS, Laboratoire de Microbiologie des Environnements Extrêmes, UMR6197, Technopôle Brest Iroise, Plouzané, France School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne, United Kingdom avignero@gmail.com.
authors.forename: Adrien
authors.identifier: http://orcid.org/0000-0003-3552-8369
authors.initials: A
authors.lastname: Vigneron
authors.affiliation: Université de Bretagne Occidentale, Laboratoire de Microbiologie des Environnements Extrêmes, UMR6197, Technopôle Brest Iroise, Plouzané, France CNRS, Laboratoire de Microbiologie des Environnements Extrêmes, UMR6197, Technopôle Brest Iroise, Plouzané, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: L'Haridon
authors.affiliation: Ifremer, Laboratoire de Microbiologie des Environnements Extrêmes, UMR6197, Technopôle Brest Iroise, Plouzané, France Université de Bretagne Occidentale, Laboratoire de Microbiologie des Environnements Extrêmes, UMR6197, Technopôle Brest Iroise, Plouzané, France CNRS, Laboratoire de Microbiologie des Environnements Extrêmes, UMR6197, Technopôle Brest Iroise, Plouzané, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Godfroy
authors.affiliation: Ifremer, Laboratoire de Microbiologie des Environnements Extrêmes, UMR6197, Technopôle Brest Iroise, Plouzané, France Université de Bretagne Occidentale, Laboratoire de Microbiologie des Environnements Extrêmes, UMR6197, Technopôle Brest Iroise, Plouzané, France CNRS, Laboratoire de Microbiologie des Environnements Extrêmes, UMR6197, Technopôle Brest Iroise, Plouzané, France School of Earth and Ocean Sciences, Cardiff University, Cardiff, United Kingdom.
authors.forename: Erwan G
authors.initials: EG
authors.lastname: Roussel
authors.affiliation: School of Earth and Ocean Sciences, Cardiff University, Cardiff, United Kingdom.
authors.forename: Barry A
authors.initials: BA
authors.lastname: Cragg
authors.affiliation: School of Earth and Ocean Sciences, Cardiff University, Cardiff, United Kingdom.
authors.forename: R John
authors.initials: RJ
authors.lastname: Parkes
authors.affiliation: Ifremer, Laboratoire de Microbiologie des Environnements Extrêmes, UMR6197, Technopôle Brest Iroise, Plouzané, France Université de Bretagne Occidentale, Laboratoire de Microbiologie des Environnements Extrêmes, UMR6197, Technopôle Brest Iroise, Plouzané, France CNRS, Laboratoire de Microbiologie des Environnements Extrêmes, UMR6197, Technopôle Brest Iroise, Plouzané, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Toffin
mesh_terms: D001105:Archaea / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D044822:Biodiversity; D002140:California; D019015:Geologic Sediments / Q000382:microbiology*; D008697:Methane / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012623:Seawater / Q000737:chemistry / Q000382:microbiology*
chemical_list: D008697:Methane