Growth rate of a clam from the galapagos rise hotspring field using natural radionuclide ratios [7]

THE submarine hydrothermal springs on the Galapagos Rift are the sites of lush biological populations supported ultimately by sulphur-oxidising bacteria utilising hydrogen sulphide transported from depth by the springs¹. Two types of bivalves, one a mytilid mussel and the other a vesicomyid, have been recovered from these thermal regions. The shells of these organisms are as much as 30 cm long. We are determining growth rates of these organisms using a method which measures natural radionuclide content². In this report we present our first results on a clam collected in the February-March 1977 Alvin dive series.