title: Microbial Communities in Methane- and Short Chain Alkane-Rich Hydrothermal Sediments of Guaymas Basin.
abstract: The hydrothermal sediments of Guaymas Basin, an active spreading center in the Gulf of California (Mexico), are rich in porewater methane, short-chain alkanes, sulfate and sulfide, and provide a model system to explore habitat preferences of microorganisms, including sulfate-dependent, methane- and short chain alkane-oxidizing microbial communities. In this study, hot sediments (above 60°C) covered with sulfur-oxidizing microbial mats surrounding a hydrothermal mound (termed "Mat Mound") were characterized by porewater geochemistry of methane, C2-C6 short-chain alkanes, sulfate, sulfide, sulfate reduction rate measurements, in situ temperature gradients, bacterial and archaeal 16S rRNA gene clone libraries and V6 tag pyrosequencing. The most abundantly detected groups in the Mat mound sediments include anaerobic methane-oxidizing archaea of the ANME-1 lineage and its sister clade ANME-1Guaymas, the uncultured bacterial groups SEEP-SRB2 within the Deltaproteobacteria and the separately branching HotSeep-1 Group; these uncultured bacteria are candidates for sulfate-reducing alkane oxidation and for sulfate-reducing syntrophy with ANME archaea. The archaeal dataset indicates distinct habitat preferences for ANME-1, ANME-1-Guaymas, and ANME-2 archaea in Guaymas Basin hydrothermal sediments. The bacterial groups SEEP-SRB2 and HotSeep-1 co-occur with ANME-1 and ANME-1Guaymas in hydrothermally active sediments underneath microbial mats in Guaymas Basin. We propose the working hypothesis that this mixed bacterial and archaeal community catalyzes the oxidation of both methane and short-chain alkanes, and constitutes a microbial community signature that is characteristic for hydrothermal and/or cold seep sediments containing both substrates.
authors: Department of Marine Sciences, University of North Carolina at Chapel Hill Chapel Hill, NC, USA.
authors: Frederick
authors: F
authors: Dowell
authors: Department of Marine Sciences, University of North Carolina at Chapel Hill Chapel Hill, NC, USA.
authors: Zena
authors: Z
authors: Cardman
authors: Department of Marine Sciences, University of North Carolina at Chapel Hill Chapel Hill, NC, USA.
authors: Srishti
authors: S
authors: Dasarathy
authors: MARUM Center for Marine Environmental Sciences and Department of Geosciences, University of BremenBremen, Germany; Department of Earth Science and Marine Science Institute, University of California at Santa BarbaraSanta Barbara, CA, USA.
authors: Matthias Y
authors: MY
authors: Kellermann
authors: MARUM Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen Bremen, Germany.
authors: Julius S
authors: JS
authors: Lipp
authors: HGF-MPG Group for Deep-Sea Ecology and Technology, Max Planck Institute for Marine Microbiology Bremen, Germany.
authors: S Emil
authors: SE
authors: Ruff
authors: School of Marine Science and Policy, University of Delaware Lewes, DE, USA.
authors: Jennifer F
authors: JF
authors: Biddle
authors: Department of Marine Sciences, University of North Carolina at Chapel Hill Chapel Hill, NC, USA.
authors: Luke J
authors: LJ
authors: McKay
authors: Department of Marine Sciences, University of North Carolina at Chapel Hill Chapel Hill, NC, USA.
authors: Barbara J
authors: BJ
authors: MacGregor
authors: Department of Microbiology, The University of Tennessee Knoxville, TN, USA.
authors: Karen G
authors: KG
authors: Lloyd
authors: Department of Marine Sciences, University of North Carolina at Chapel Hill Chapel Hill, NC, USA.
authors: Daniel B
authors: DB
authors: Albert
authors: Department of Marine Sciences, University of North Carolina at Chapel Hill Chapel Hill, NC, USA.
authors: Howard
authors: H
authors: Mendlovitz
authors: MARUM Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen Bremen, Germany.
authors: Kai-Uwe
authors: KU
authors: Hinrichs
authors: Department of Marine Sciences, University of North Carolina at Chapel Hill Chapel Hill, NC, USA.
authors: Andreas
authors: A
authors: Teske
keywords: ANME; Guaymas Basin; alkanes; hydrothermal vents; methane; sediment