Deep-biosphere methane production stimulated by geofluids in the Nankai accretionary complex
Name
eaao4631.full.pdf
Size
2.05 MB
Format
Adobe PDF
Checksum (MD5)
efbcd03113ce0ac7ced2b0a7241d0737
Author(s)
Ijiri, Akira
Inagaki, Fumio
Kubo, Yusuke
Adhikari, Rishi R.
Hattori, Shohei
Hoshino, Tatsuhiko
Imachi, Hiroyuki
Kawagucci, Shinsuke
Morono, Yuki
Ohtomo, Yoko
Date Issued
May 2018
Journal
Science Advances
Publisher
American Association for the Advancement of Science (AAAS)
Citation
Ijiri, Akira et al. “Deep-Biosphere Methane Production Stimulated by Geofluids in the Nankai Accretionary Complex.” Science Advances 4, 6 (June 2018): eaao4631 © 2018 The Authors
Version
Final published version
Abstract
Microbial life inhabiting subseafloor sediments plays an important role in Earth’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.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Terms of Use
Creative Commons Attribution-NonCommercial 4.0 International
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1126/sciadv.aao4631
