Pumping Rates, Water Pressures, and Oxygen Use in Eight Species of Marine Bivalve Molluscs from British Columbia

Pumping characteristics and oxygen utilization for Solemya reidi, Yoldia thraciaeformis, Chlamys hastata, Mytilus edulis, Crassostrea gigas, Clinocardium nuttallii, Saxidomus giganteus, and Mya truncata were studied. Pressures were recorded using a Yale A79 spinal tap needle inserted in the pallial cavity or siphonal aperture. Pumping volumes were determined through particulate analysis using a Model B Coulter counter and oxygen consumption by standard Winkler titration modified for small samples. The species chosen were selected to represent progressive increases in gill complexity and siphon length. The minimum pressure differential across the gill (20 Pa) was observed for Y. thraciaeformis while the maximum pressure gradient (600 Pa) was recorded for M. truncata. Pumping rates varied from 1.41 L∙h−1∙g−1 (Y. thraciaeformis) to 4.71 L∙h−1∙g−1 (C. hastata) and species with siphons tended to pump at lower rates. The deeply burrowing M. truncata consumed 3.5 times as much oxygen (0.63 mL O2∙h−1∙g−1) as S. reidi (0.18 mL O2∙h−1∙g−1) which inhabits anoxic environments. For all species, the metabolic cost of pumping was less than 1% of the total oxygen uptake.