Delta-C-13, Delta-N-15 and Delta-O-18 of Calyptogena-Phaseoliformis (Bivalve Mollusk) from the Ascension Fan-Valley near Monterey, California

The delta-C-13 and delta-N-15of the soft tissues of two calyptogena phaseoliformis specimens sampled from the floor of Ascension Fan-Valley, off the Monterey Peninsula, California, ranged from -35.0 to -33.6 parts per thousands, respectively. The carbon isotope abundances are similar to those of other Calyptogena known or believed to be nutritionally dependent on sulfide-based chemoautotrophic symbionts. Calyptogena delta-15N values and their geographic variation indicate an unusual source of dietary nitrogen for these animals. The delta-C-13 and delta-O-18 values for Calyptogena shells from the Ascension and Monterey Fan-Valleys approximate those reported for Calyptogena from three other locations in the Pacific and appear to reflect shell formation from constituents within ambient deep-ocean water.