title: Interrogation of Chesapeake Bay sediment microbial communities for intrinsic alkane-utilizing potential under anaerobic conditions.
abstract: Based on the transient exposure of Chesapeake Bay sediments to hydrocarbons and the metabolic versatility of known anaerobic alkane-degrading microorganisms, it was hypothesized that distinct Bay sediment communities, governed by geochemical gradients, would have intrinsic alkane-utilizing potential under sulfate-reducing and/or methanogenic conditions. Sediment cores were collected along a transect of the Bay. Community DNA was interrogated via pyrosequencing of 16S rRNA genes, PCR of anaerobic hydrocarbon activation genes, and qPCR of 16S rRNA genes and genes involved in sulfate reduction/methanogenesis. Site sediments were used to establish microcosms amended with n-hexadecane under sulfate-reducing and methanogenic conditions. Sequencing of 16S rRNA genes indicated that sediments associated with hypoxic water columns contained significantly greater proportions of Bacteria and Archaea consistent with syntrophic degradation of organic matter and methanogenesis compared to less reduced sediments. Microbial taxa frequently associated with hydrocarbon-degrading communities were found throughout the Bay, and the genetic potential for hydrocarbon metabolism was demonstrated via the detection of benzyl-(bssA) and alkylsuccinate synthase (assA) genes. Although microcosm studies did not indicate sulfidogenic alkane degradation, the data suggested that methanogenic conversion of alkanes was occurring. These findings highlight the potential role that anaerobic microorganisms could play in the bioremediation of hydrocarbons in the Bay.
authors.affiliation: University of Oklahoma, Department of Microbiology and Plant Biology, George Lynn Cross Hall, 770 Van Vleet Oval, Norman, OK 73019, USA.
authors.forename: Jamie M
authors.initials: JM
authors.lastname: Johnson
authors.affiliation: University of Oklahoma, Department of Microbiology and Plant Biology, George Lynn Cross Hall, 770 Van Vleet Oval, Norman, OK 73019, USA.
authors.forename: Boris
authors.initials: B
authors.lastname: Wawrik
authors.affiliation: University of Oklahoma, Department of Microbiology and Plant Biology, George Lynn Cross Hall, 770 Van Vleet Oval, Norman, OK 73019, USA.
authors.forename: Catherine
authors.initials: C
authors.lastname: Isom
authors.affiliation: University of Oklahoma, Department of Microbiology and Plant Biology, George Lynn Cross Hall, 770 Van Vleet Oval, Norman, OK 73019, USA.
authors.forename: Wilford B
authors.initials: WB
authors.lastname: Boling
authors.affiliation: University of Oklahoma, Department of Microbiology and Plant Biology, George Lynn Cross Hall, 770 Van Vleet Oval, Norman, OK 73019, USA acallaghan@ou.edu.
authors.forename: Amy V
authors.initials: AV
authors.lastname: Callaghan
mesh_terms: D000473:Alkanes / Q000378:metabolism*; D000693:Anaerobiosis; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D061006:Bays / Q000382:microbiology; D001673:Biodegradation, Environmental; D019755:Carbon-Carbon Lyases / Q000235:genetics; D019615:Crenarchaeota / Q000235:genetics / Q000378:metabolism*; D019605:Euryarchaeota / Q000235:genetics / Q000378:metabolism*; D019015:Geologic Sediments / Q000382:microbiology*; D008697:Methane / Q000096:biosynthesis; D010084:Oxidation-Reduction; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013431:Sulfates / Q000378:metabolism
chemical_list: D000473:Alkanes; D012336:RNA, Ribosomal, 16S; D013431:Sulfates; D019755:Carbon-Carbon Lyases; C114354:benzylsuccinate synthase; C007932:n-hexadecane; D008697:Methane
keywords: biodegradation; estuary; oil; pollution