Microbial community stratification controlled by the subseafloor fluid flow and geothermal gradient at the Iheya North hydrothermal field in the mid-Okinawa trough (Integrated ocean drilling program expedition 331)

authored by

Katsunori Yanagawa, Anja Breuker, Axel Schippers, Manabu Nishizawa, Akira Ijiri, Miho Hirai, Yoshihiro Takaki, Michinari Sunamura, Tetsuro Urabe, Takuro Nunoura, Ken Takai

Abstract

The impacts of lithologic structure and geothermal gradient on subseafloor microbial communities were investigated at a marginal site of the Iheya North hydrothermal field in the Mid-Okinawa Trough. Subsurface marine sediments composed of hemipelagic muds and volcaniclastic deposits were recovered through a depth of 151mbelow the seafloor at site C0017 during Integrated Ocean Drilling Program Expedition 331. Microbial communities inferred from 16S rRNA gene clone sequencing in low-temperature hemipelagic sediments were mainly composed of members of the Chloroflexi and deep-sea archaeal group. In contrast, 16S rRNA gene sequences of marine group I Thaumarchaeota dominated the microbial phylotype communities in the coarse-grained pumiceous gravels interbedded between the hemipelagic sediments. Based on the physical properties of sediments such as temperature and permeability, the porewater chemistry, and the microbial phylotype compositions, the shift in the physical properties of the sediments is suggested to induce a potential subseafloor recharging flow of oxygenated seawater in the permeable zone, leading to the generation of variable chemical environments and microbial communities in the subseafloor habitats. In addition, the deepest section of sediments under high-temperature conditions (~90°C) harbored the sequences of an uncultivated archaeal lineage of hot water crenarchaeotic group IV that may be associated with the high-temperature hydrothermal fluid flow. These results indicate that the subseafloor microbial community compositions and functions at the marginal site of the hydrothermal field are highly affected by the complex fluid flow structure, such as recharging seawater and underlying hydrothermal fluids, coupled with the lithologic transition of sediments.

Organisation(s)

Institute of Microbiology

External Organisation(s)

Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
University of Tokyo
Federal Institute for Geosciences and Natural Resources (BGR)

Type

Article

Journal

Applied and Environmental Microbiology

Volume

80

Pages

6126-6135

No. of pages

10

ISSN

0099-2240

Publication date

09.09.2014

Publication status

E-pub ahead of print

Peer reviewed

Yes

ASJC Scopus subject areas

Biotechnology, Food Science, Applied Microbiology and Biotechnology, Ecology

Sustainable Development Goals

SDG 14 - Life Below Water

Electronic version(s)

https://doi.org/10.1128/AEM.01741-14 (Access: Open)