title: Microbial community structure of hydrothermal deposits from geochemically different vent fields along the Mid-Atlantic Ridge.
abstract: To evaluate the effects of local fluid geochemistry on microbial communities associated with active hydrothermal vent deposits, we examined the archaeal and bacterial communities of 12 samples collected from two very different vent fields: the basalt-hosted Lucky Strike (37°17'N, 32°16.3'W, depth 1600-1750 m) and the ultramafic-hosted Rainbow (36°13'N, 33°54.1'W, depth 2270-2330 m) vent fields along the Mid-Atlantic Ridge (MAR). Using multiplexed barcoded pyrosequencing of the variable region 4 (V4) of the 16S rRNA genes, we show statistically significant differences between the archaeal and bacterial communities associated with the different vent fields. Quantitative polymerase chain reaction (qPCR) assays of the functional gene diagnostic for methanogenesis (mcrA), as well as geochemical modelling to predict pore fluid chemistries within the deposits, support the pyrosequencing observations. Collectively, these results show that the less reduced, hydrogen-poor fluids at Lucky Strike limit colonization by strict anaerobes such as methanogens, and allow for hyperthermophilic microaerophiles, like Aeropyrum. In contrast, the hydrogen-rich reducing vent fluids at the ultramafic-influenced Rainbow vent field support the prevalence of methanogens and other hydrogen-oxidizing thermophiles at this site. These results demonstrate that biogeographical patterns of hydrothermal vent microorganisms are shaped in part by large scale geological and geochemical processes.
authors.affiliation: Department of Biology, Portland State University, Portland, OR 97201, USA.
authors.forename: Gilberto E
authors.initials: GE
authors.lastname: Flores
authors.forename: James H
authors.initials: JH
authors.lastname: Campbell
authors.forename: Julie D
authors.initials: JD
authors.lastname: Kirshtein
authors.forename: Jennifer
authors.initials: J
authors.lastname: Meneghin
authors.forename: Mircea
authors.initials: M
authors.lastname: Podar
authors.forename: Joshua I
authors.initials: JI
authors.lastname: Steinberg
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Seewald
authors.forename: Margaret Kingston
authors.initials: MK
authors.lastname: Tivey
authors.forename: Mary A
authors.initials: MA
authors.lastname: Voytek
authors.forename: Zamin K
authors.initials: ZK
authors.lastname: Yang
authors.forename: Anna-Louise
authors.initials: AL
authors.lastname: Reysenbach
mesh_terms: D001105:Archaea / Q000145:classification* / Q000235:genetics; D001419:Bacteria / Q000145:classification* / Q000235:genetics; D044822:Biodiversity; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology; D005844:Geology; D060086:Hydrothermal Vents / Q000737:chemistry / Q000382:microbiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012623:Seawater / Q000737:chemistry / Q000382:microbiology
chemical_list: D012336:RNA, Ribosomal, 16S