title: Characteristics of microbial communities in crustal fluids in a deep-sea hydrothermal field of the suiyo seamount.
abstract: To directly access the sub-seafloor microbial communities, seafloor drilling has been done in a deep-sea hydrothermal field of the Suiyo Seamount, Izu-Bonin Arc, Western Pacific. In the present study, crustal fluids were collected from the boreholes, and the bacterial and archaeal communities in the fluids were investigated by culture-independent molecular analysis based on 16S rRNA gene sequences. Bottom seawater, sands, rocks, sulfide mound, and chimneys were also collected around the boreholes and analyzed for comparisons. Comprehensive analysis revealed the characteristics of the microbial community composition in the crustal fluids. Phylotypes closely related to cultured species, e.g., Alteromonas, Halomonas, Marinobacter, were relatively abundant in some crustal fluid samples, whereas the phylotypes related to Pelagibacter and the SUP05-group were relatively abundant in the seawater samples. Phylotypes related to other uncultured environmental clones in Alphaproteobacteria and Gammaproteobacteria were relatively abundant in the sand, rock, sulfide mound, and chimney samples. Furthermore, comparative analysis with previous studies of the Suiyo Seamount crustal fluids indicates the change in the microbial community composition for 3 years. Our results provide novel insights into the characteristics of the microbial communities in crustal fluids beneath a deep-sea hydrothermal field.
authors.affiliation: Japan Collection of Microorganisms, RIKEN BioResource Center Wako-shi, Saitama, Japan ; Department of Molecular Biology, Tokyo University of Pharmacy and Life Science Hachioji, Tokyo, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Kato
authors.forename: Michiyuki
authors.initials: M
authors.lastname: Nakawake
authors.forename: Junko
authors.initials: J
authors.lastname: Kita
authors.forename: Toshiro
authors.initials: T
authors.lastname: Yamanaka
authors.forename: Motoo
authors.initials: M
authors.lastname: Utsumi
authors.forename: Kei
authors.initials: K
authors.lastname: Okamura
authors.forename: Jun-Ichiro
authors.initials: J
authors.lastname: Ishibashi
authors.forename: Moriya
authors.initials: M
authors.lastname: Ohkuma
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yamagishi
keywords: 16S rRNA gene; Island-Arc; Western Pacific; archaea; bacteria; crustal fluids; deep-sea hydrothermal vent; sub-seafloor biosphere