@article{9bd6cdaff4424b2ebee56a47ff7f1aee,
title = "Deep-biosphere methane production stimulated by geofluids in the nankai accretionary complex",
abstract = "Microbial life inhabiting subseafloor sediments plays an important role in Earth{\textquoteright}s carbon cycle. However, the impact of geodynamic processes on the distributions and carbon-cycling activities of subseafloor life remains poorly constrained. We explore a submarine mud volcano of the Nankai accretionary complex by drilling down to 200 m below the summit. Stable isotopic compositions of water and carbon compounds, including clumped methane isotopologues, suggest that ~90% of methane is microbially produced at 16° to 30°C and 300 to 900 m below seafloor, corresponding to the basin bottom, where fluids in the accretionary prism are supplied via megasplay faults. Radiotracer experiments showed that relatively small microbial populations in deep mud volcano sediments (102 to 103 cells cm−3) include highly active hydrogenotrophic methanogens and acetogens. Our findings indicate that subduction-associated fluid migration has stimulated microbial activity in the mud reservoir and that mud volcanoes may contribute more substantially to the methane budget than previously estimated.",
author = "Akira Ijiri and Fumio Inagaki and Yusuke Kubo and Adhikari, {Rishi R.} and Shohei Hattori and Tatsuhiko Hoshino and Hiroyuki Imachi and Shinsuke Kawagucci and Yuki Morono and Yoko Ohtomo and Shuhei Ono and Sanae Sakai and Ken Takai and Tomohiro Toki and Wang, {David T.} and Yoshinaga, {Marcos Y.} and Arnold, {Gail L.} and Juichiro Ashi and Case, {David H.} and Tomas Feseker and Hinrichs, {Kai Uwe} and Yojiro Ikegawa and Minoru Ikehara and Jens Kallmeyer and Hidenori Kumagai and Lever, {Mark A.} and Sumito Morita and Nakamura, {Ko ichi} and Yuki Nakamura and Manabu Nishizawa and Orphan, {Victoria J.} and Hans R{\o}y and Frauke Schmidt and Atsushi Tani and Wataru Tanikawa and Takeshi Terada and Hitoshi Tomaru and Takeshi Tsuji and Urumu Tsunogai and Yamaguchi, {Yasuhiko T.} and Naohiro Yoshida",
note = "Funding Information: We thank all crews, drilling team members, and technical staffs on the deep-sea drilling vessel Chikyu and the research vessel Hakuhomaru for support with core sampling from KMV#5 during JAMSTEC Chikyu Expeditions 903, 906, and KH06-04 cruises. We are also grateful to IODP for providing sediment core samples from Site C0002 during Expedition 315. We are grateful to S. Fukunaga, S. Hashimoto, K. Iijima, A. Imajo, H. Machiyama, Y. Nishio, S. Tanaka, H. Tomiyama, and N. Xiao for useful discussions and/or technical assistance. This is a contribution to the Deep Carbon Observatory. This study was supported, in part, by the Japan Society for the Promotion of Science (JSPS) Strategic Fund for Strengthening Leading-Edge Research and Development (to JAMSTEC and F.I.), the JSPS Funding Program for Next Generation World-Leading Researchers (GR102 to F.I.), the Grant-in-Aid for Science Research (nos. 23681007, 26287128, and 17H01871 to A.I.; no. 26251041 to F.I.; no. 17H06105 to N.Y.), and the East Asia and Pacific Summer Institutes program through the NSF and JSPS (no. 1308171 to D.H.C.). Lipid analyses by M.Y.Y. and shipboard work by F.S. were financed by the European Research Council under the European Union{\textquoteright}s Seventh Framework Programme—“Ideas” Specific Programme (no. 247153 to K.-U.H.). Publisher Copyright: Copyright {\textcopyright} 2018 The Authors,",
year = "2018",
month = jun,
day = "13",
doi = "10.1126/sciadv.aao4631",
language = "English",
volume = "4",
journal = "Science Advances",
issn = "2375-2548",
publisher = "American Association for the Advancement of Science",
number = "6",
}