Field and laboratory measurements of bivalve filtration of natural marine bacterioplankton1

Abstract

Clearance of natural bacterioplankton and phytoplankton by Mytilus edulis, Geukensia demissa, and Mya arenaria was measured in the laboratory. Of the three, only Geukensia proved capable of efficient clearance of bacteria. Field measurements of clearance across a 46‐m‐wide Mytilus bed showed substantial removal of phytoplankton but no effect on bacterial concentrations. Measurements of the living gill tissue of the two mussel species revealed closer spacing and more lateral overlapping of filtering cilia in G. demissa. The ability of Geukensia to filter bacteria appears to be a key adaptation to a food resource deriving largely from salt marsh primary production.