A NEW METHOD FOR RECORDING THE IN-SITU PUMPING ACTIVITY OF INFAUNAL BIVALVES

A new method for measuring the pumping activity of infaunal bivalves i s described. The method is based on the simultaneous recording of thre e temperatures:(1) the temperature of the sea water above the bivalve, (2) the temperature of the sediment and (3) the internal temperature of the bivalve. When thermic shifts between sediment and sea water are induced by the sun and/or the ground water, comparison of the three t emperatures provides information on the pumping activity of the bivalv e. The method was applied during the day to Tapes decussatus and Rudit apes philippinarum (Veneridae). Their pumping activity appears continu ous except during emersion at ebb. Sestonic concentrations as high as 325 mg 1(-1) induced no detectable interruption. Analysis of the data suggests that in situ pumping rate is not constant but fluctuates.