TY - JOUR
T1 - Stable isotopic compositions of methane and carbon monoxide in the Suiyo hydrothermal plume, Izu-Bonin arc
T2 - Tracers for microbial consumption/ production
AU - Tsunogai, Urumu
AU - Nakagawa, Fumiko
AU - Gamo, Toshitaka
AU - Ishibashi, Junichiro
N1 - Funding Information:
This research was supported by the following grants: MEXT Grant-in Aid Scientific Research Nos. 13740313 and 14048202, MEXT Grant-in Aid for the 21st Century COE Program “Neo-Science of Natural History” at Hokkaido University, MEXT Special Coordination Fund “Archaean Park” project, and NEDO Proposal Based Research and Development Project (ID 02A53002d). The comments and suggestions from Dr. W. Bach and an anonymous reviewer are very helpful to improve this manuscript.
PY - 2005/9/15
Y1 - 2005/9/15
N2 - Effluent hydrothermal water samples in and around the water column of the Suiyo seamount caldera (ca. 2 km diameter), Izu-Bonin arc, were taken to determine concentrations and stable carbon isotopic compositions (δ13C) of methane (CH4) and carbon monoxide (CO) in the plume. Venting fluids on the caldera floor (ca. 1370 m depth) were also examined, using the manned submersible Shinkai 2000, to compare the chemical composition and isotopic composition of CH4 and CO with those in the hydrothermal plume. Strong CH4 enrichment was detected not only in the water column within the caldera, but also on those outside the caldera at the depth of ca. 1100 m, the sill depth of the caldera wall. Within the plume, we also detected significant CO enrichment. The δ13C of CO in the plume, however, exhibited highly 13C-depleted values (-110‰VPDB to -60‰VPDB) compared with those in seafloor venting hydrothermal fluids (around -31‰VPDB). Besides, the plume samples exhibited higher CO/CH4 ratios depending on the distance from the seafloor venting site. We conclude that in situ microbial activity in the plume causes the CO enrichment in the hydrothermal plume. The present results suggest that CO enrichment in deep sea water could act as a new tracer for unidentified seafloor hydrothermal activities, especially for detecting plumes distant from venting sites, as well as for quantifying in situ microbial activity related to CO production in hydrothermal plumes.
AB - Effluent hydrothermal water samples in and around the water column of the Suiyo seamount caldera (ca. 2 km diameter), Izu-Bonin arc, were taken to determine concentrations and stable carbon isotopic compositions (δ13C) of methane (CH4) and carbon monoxide (CO) in the plume. Venting fluids on the caldera floor (ca. 1370 m depth) were also examined, using the manned submersible Shinkai 2000, to compare the chemical composition and isotopic composition of CH4 and CO with those in the hydrothermal plume. Strong CH4 enrichment was detected not only in the water column within the caldera, but also on those outside the caldera at the depth of ca. 1100 m, the sill depth of the caldera wall. Within the plume, we also detected significant CO enrichment. The δ13C of CO in the plume, however, exhibited highly 13C-depleted values (-110‰VPDB to -60‰VPDB) compared with those in seafloor venting hydrothermal fluids (around -31‰VPDB). Besides, the plume samples exhibited higher CO/CH4 ratios depending on the distance from the seafloor venting site. We conclude that in situ microbial activity in the plume causes the CO enrichment in the hydrothermal plume. The present results suggest that CO enrichment in deep sea water could act as a new tracer for unidentified seafloor hydrothermal activities, especially for detecting plumes distant from venting sites, as well as for quantifying in situ microbial activity related to CO production in hydrothermal plumes.
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U2 - 10.1016/j.epsl.2005.05.042
DO - 10.1016/j.epsl.2005.05.042
M3 - Article
AN - SCOPUS:24144498014
VL - 237
SP - 326
EP - 340
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
SN - 0012-821X
IS - 3-4
ER -