Article ID Journal Published Year Pages File Type
4700664 Chemical Geology 2008 8 Pages PDF
Abstract
To investigate symbiotic bacterial ecosystems at different deep-sea hydrothermal systems in the northwestern Pacific, compound-specific carbon and hydrogen isotope analyses of lipid biomarkers have been performed in addition to bulk C, H, N, S and O isotope analyses on Bathymodiolus mussels from the Hatoma seamount (B. platifrons), the Daiyon-Yonaguni (Yonaguni) knoll (B. platifrons), and the Suiyo seamount (B. septemdierum). The two B. platifrons contain large amounts of diploptene, while no hopanoid is detected in B. septemdierum, suggesting that B. platifrons and B. septemdierum harbors methanotrophic and thiotrophic bacteria, respectively. In spite of the same symbiont, the large bulk δ13C difference between the Hatoma (− 44.8‰) and Yonaguni (− 24.5‰) mussels reflects isotopically distinct hydrothermal CH4 (Hatoma: ~ − 48‰, Yonaguni: ~ −26‰) as a carbon source. Fatty acids of the Hatoma and Yonaguni mussels are more enriched in D (− 144 to − 101‰) than the Suiyo mussel (− 265 to − 162‰), suggesting that D-depleted magmatic water or D-enriched hydrogen derived from CH4 could be a partial hydrogen source for methanotrophy or thiotrophy, respectively. Apparent positive correlations are observed between δ13C and δD of the bulk and biomarkers for each mussel due to similar biochemical processes during de novo synthesis. The compound-specific δ13C and δD variations have provided much information on not only distinct carbon and hydrogen sources but also the lipid synthesis with respect to different symbiotic bacterial ecosystems.
Related Topics
Physical Sciences and Engineering Earth and Planetary Sciences Geochemistry and Petrology
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