Open AccessVariability in microbial community and venting chemistry in a sediment‐hosted backarc hydrothermal system: Impacts of subseafloor phase‐separation
Author(s) -
Nakagawa Satoshi,
Takai Ken,
Inagaki Fumio,
Chiba Hitoshi,
Ishibashi Junichiro,
Kataoka Satoshi,
Hirayama Hisako,
Nunoura Takuro,
Horikoshi Koki,
Sako Yoshihiko
Publication year - 2005
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1016/j.femsec.2005.03.007
Subject(s) - microbial population biology , thermophile , hydrothermal vent , chimney (locomotive) , methanogenesis , hydrothermal circulation , sediment , biology , methane , environmental chemistry , ecology , oceanography , chemistry , geology , bacteria , paleontology , inlet
Phase‐separation and ‐segregation (boiling/distillation of subseafloor hydrothermal fluids) represent the primary mechanisms causing intra‐field variations in vent fluid compositions. To determine whether this geochemical process affects the formation of microbial communities, we examined the microbial communities at three different vent sites located within a few tens meters of one another. In addition to chimney structures, colonization devices capturing subseafloor communities entrained by the vent fluids were studied, using culture‐dependent and ‐independent methods. Microbiological analyses demonstrated the occurrence of distinctive microbial communities in each of the hydrothermal niches. Within a chimney structure, there was a transition from a mixed community of mesophiles and thermophiles in the exterior parts to thermophiles in the interior. Beside the transition within a chimney structure, intra‐field variations in microbial communities in vent fluids were apparent. Geochemical analysis demonstrated that different vent fluids have distinctive end‐member compositions as a consequence of subseafloor phase‐separation and ‐segregation, which were designated gas‐depleted, normal and gas‐enriched fluids. In comparison to gas‐depleted and normal fluids, gas‐enriched fluids harbored more abundant chemolithoautotrophs with gaseous component‐dependent energy metabolism, such as hydrogenotrophic methanogenesis. Subseafloor phase‐separation and ‐segregation may play a key role in supplying energy and carbon sources to vent‐associated chemolithoautotrophs and subvent microbial communities.