title: Molecular phylogenetic and chemical analyses of the microbial mats in deep-sea cold seep sediments at the northeastern Japan Sea.
abstract: Microbial communities inhabiting deep-sea cold seep sediments at the northeastern Japan Sea were characterized by molecular phylogenetic and chemical analyses. White patchy microbial mats were observed along the fault offshore the Hokkaido Island and sediment samples were collected from two stations at the southern foot of the Shiribeshi seamount (M1 site at a depth of 2,961 m on the active fault) and off the Motta Cape site (M2 site at a depth of 3,064 m off the active fault). The phylogenetic and terminal-restriction fragment polymorphism analyses of PCR-amplified 16S rRNA genes revealed that microbial community structures were different between two sampling stations. The members of ANME-2 archaea and diverse bacterial components including sulfate reducers within Deltaproteobacteria were detected from M1 site, indicating the occurrence of biologically mediated anaerobic oxidation of methane, while microbial community at M2 site was predominantly composed of members of Marine Crenarchaeota group I, sulfate reducers of Deltaproteobacteria, and sulfur oxidizers of Epsilonproteobacteria. Chemical analyses of seawater above microbial mats suggested that concentrations of sulfate and methane at M1 site were largely decreased relative to those at M2 site and carbon isotopic composition of methane at M1 site shifted heavier ((13)C-enriched), the results of which are consistent with molecular analyses. These results suggest that the mat microbial communities in deep-sea cold seep sediments at the northeastern Japan Sea are significantly responsible for sulfur and carbon circulations and the geological activity associated with plate movements serves unique microbial habitats in deep-sea environments.
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Toyo University, Kawagoe, 350-0815, Japan.
authors.forename: Shizuka
authors.initials: S
authors.lastname: Arakawa
authors.forename: Takako
authors.initials: T
authors.lastname: Sato
authors.forename: Rumi
authors.initials: R
authors.lastname: Sato
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Gamo
authors.forename: Urumu
authors.initials: U
authors.lastname: Tsunogai
authors.forename: Akinari
authors.initials: A
authors.lastname: Hirota
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Ron
authors.initials: R
authors.lastname: Usami
authors.forename: Fumio
authors.initials: F
authors.lastname: Inagaki
authors.forename: Chiaki
authors.initials: C
authors.lastname: Kato
mesh_terms: D001419:Bacteria / Q000235:genetics* / Q000302:isolation & purification* / Q000378:metabolism; D019143:Evolution, Molecular; D019015:Geologic Sediments / Q000382:microbiology*; D007564:Japan; D008697:Methane / Q000737:chemistry; D009792:Oceans and Seas; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013431:Sulfates / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D012336:RNA, Ribosomal, 16S; D013431:Sulfates; D014867:Water; D008697:Methane