title: Archaeal diversity and distribution along thermal and geochemical gradients in hydrothermal sediments at the Yonaguni Knoll IV hydrothermal field in the Southern Okinawa trough.
abstract: A variety of archaeal lineages have been identified using culture-independent molecular phylogenetic surveys of microbial habitats occurring in deep-sea hydrothermal environments such as chimney structures, sediments, vent emissions, and chemosynthetic macrofauna. With the exception of a few taxa, most of these archaea have not yet been cultivated, and their physiological and metabolic traits remain unclear. In this study, phylogenetic diversity and distribution profiles of the archaeal genes encoding small subunit (SSU) rRNA, methyl coenzyme A (CoA) reductase subunit A, and the ammonia monooxygenase large subunit were characterized in hydrothermally influenced sediments at the Yonaguni Knoll IV hydrothermal field in the Southern Okinawa Trough. Sediment cores were collected at distances of 0.5, 2, or 5 m from a vent emission (90 degrees C). A moderate temperature gradient extends both horizontally and vertically (5 to 69 degrees C), indicating the existence of moderate mixing between the hydrothermal fluid and the ambient sediment pore water. The mixing of reductive hot hydrothermal fluid and cold ambient sediment pore water establishes a wide spectrum of physical and chemical conditions in the microbial habitats that were investigated. Under these different physico-chemical conditions, variability in archaeal phylotype composition was observed. The relationship between the physical and chemical parameters and the archaeal phylotype composition provides important insight into the ecophysiological requirements of uncultivated archaeal lineages in deep-sea hydrothermal vent environments, giving clues for approximating culture conditions to be used in future culturing efforts.
authors.affiliation: Subsurface Geobiology and Advanced Research Project, Extremobiosphere Research Program, Institute of Biogeosciences, JAMSTEC, 2-15 Natsushima-cho, Yokosuka 237-0061, Japan. takuron@jamstec.go.jp
authors.forename: Takuro
authors.initials: T
authors.lastname: Nunoura
authors.forename: Hanako
authors.initials: H
authors.lastname: Oida
authors.forename: Miwako
authors.initials: M
authors.lastname: Nakaseama
authors.forename: Ayako
authors.initials: A
authors.lastname: Kosaka
authors.forename: Satoru B
authors.initials: SB
authors.lastname: Ohkubo
authors.forename: Toru
authors.initials: T
authors.lastname: Kikuchi
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kazama
authors.forename: Shoko
authors.initials: S
authors.lastname: Hosoi-Tanabe
authors.forename: Ko-Ichi
authors.initials: K
authors.lastname: Nakamura
authors.forename: Masataka
authors.initials: M
authors.lastname: Kinoshita
authors.forename: Hisako
authors.initials: H
authors.lastname: Hirayama
authors.forename: Fumio
authors.initials: F
authors.lastname: Inagaki
authors.forename: Urumu
authors.initials: U
authors.lastname: Tsunogai
authors.forename: Jun-Ichiro
authors.initials: J
authors.lastname: Ishibashi
authors.forename: Ken
authors.initials: K
authors.lastname: Takai
mesh_terms: D001105:Archaea / Q000145:classification / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification*; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D017753:Ecosystem; D019766:Genes, Archaeal; D014644:Genetic Variation; D019015:Geologic Sediments / Q000382:microbiology*; D007564:Japan; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000235:genetics; D010802:Phylogeny; D019642:RNA, Archaeal / Q000235:genetics; D012335:RNA, Ribosomal / Q000235:genetics; D012623:Seawater / Q000382:microbiology*; D013696:Temperature
chemical_list: D017931:DNA Primers; D019642:RNA, Archaeal; D012335:RNA, Ribosomal; D010088:Oxidoreductases; C045582:ammonia monooxygenase