Abstract
Sulfur isotope composition (δ34S) was measured for soft tissues of Calyptogena soyoae from a cold seep off Hatsushima Islands, Sagami Bay, central Japan. The δ34S values of soft tissues of six specimens collected from one colony greatly but systematically vary from one specimen to another, i.e., gill, -29.1 to -17.2; adductor, -28.0 to -24.5; foot, -17.2 to -15.2; mantle, -10.6 to -7.8‰. The observed isotopic variation between adductor, foot and mantle of a single specimen was interpreted in terms of assimilation of sulfur of different sources; biogenic hydrogen sulfide with lower δ34S (around -20‰) and seawater-sulfate with higher δ34S (+20‰) values.
