title: Geochemical, metagenomic and metaproteomic insights into trace metal utilization by methane-oxidizing microbial consortia in sulphidic marine sediments.
abstract: Microbes have obligate requirements for trace metals in metalloenzymes that catalyse important biogeochemical reactions. In anoxic methane- and sulphide-rich environments, microbes may have unique adaptations for metal acquisition and utilization because of decreased bioavailability as a result of metal sulphide precipitation. However, micronutrient cycling is largely unexplored in cold (≤ 10°C) and sulphidic (> 1 mM ΣH(2)S) deep-sea methane seep ecosystems. We investigated trace metal geochemistry and microbial metal utilization in methane seeps offshore Oregon and California, USA, and report dissolved concentrations of nickel (0.5-270 nM), cobalt (0.5-6 nM), molybdenum (10-5600 nM) and tungsten (0.3-8 nM) in Hydrate Ridge sediment porewaters. Despite low levels of cobalt and tungsten, metagenomic and metaproteomic data suggest that microbial consortia catalysing anaerobic oxidation of methane (AOM) utilize both scarce micronutrients in addition to nickel and molybdenum. Genetic machinery for cobalt-containing vitamin B12 biosynthesis was present in both anaerobic methanotrophic archaea (ANME) and sulphate-reducing bacteria. Proteins affiliated with the tungsten-containing form of formylmethanofuran dehydrogenase were expressed in ANME from two seep ecosystems, the first evidence for expression of a tungstoenzyme in psychrophilic microorganisms. Overall, our data suggest that AOM consortia use specialized biochemical strategies to overcome the challenges of metal availability in sulphidic environments.
authors.affiliation: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, 91125, USA.
authors.forename: Jennifer B
authors.initials: JB
authors.lastname: Glass
authors.forename: Hang
authors.initials: H
authors.lastname: Yu
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Steele
authors.forename: Katherine S
authors.initials: KS
authors.lastname: Dawson
authors.forename: Shulei
authors.initials: S
authors.lastname: Sun
authors.forename: Karuna
authors.initials: K
authors.lastname: Chourey
authors.forename: Chongle
authors.initials: C
authors.lastname: Pan
authors.forename: Robert L
authors.initials: RL
authors.lastname: Hettich
authors.forename: Victoria J
authors.initials: VJ
authors.lastname: Orphan
mesh_terms: D001105:Archaea / Q000235:genetics*; D019843:Archaeal Proteins / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001692:Biological Transport; D002140:California; D019766:Genes, Archaeal; D005798:Genes, Bacterial; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology*; D054892:Metagenome; D008697:Methane / Q000378:metabolism; D059013:Microbial Consortia / Q000235:genetics*; D008827:Microbiological Phenomena; D008982:Molybdenum / Q000378:metabolism; D009532:Nickel / Q000378:metabolism; D009922:Oregon; D010084:Oxidation-Reduction; D010802:Phylogeny; D020543:Proteome / Q000235:genetics / Q000378:metabolism; D016999:Sulfur-Reducing Bacteria / Q000235:genetics*; D014414:Tungsten / Q000378:metabolism
chemical_list: D019843:Archaeal Proteins; D001426:Bacterial Proteins; D020543:Proteome; D009532:Nickel; D008982:Molybdenum; D008697:Methane; D014414:Tungsten