A new method for recording the in situ pumping activity of infaunal bivalves

Abstract

A new method for measuring the pumping activity of infaunal bivalves is described. The method is based on the simultaneous recording of three 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 temperatures provides information on the pumping activity of the bivalve. The method was applied during the day to Tapes decussatus and Ruditapes philippinarum (Veneridae). Their pumping activity appears continuous 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.