CONTRIBUTIONS OF BACTERIA AND SEDIMENTARY ORGANIC-MATTER TO THE DIET OF NUCULA-PROXIMA, A DEPOSIT-FEEDING PROTOBRANCHIATE BIVALVE

Laboratory experiments were conducted to determine the influence of changes in sedimentary organic matter and bacteria on ingestion and absorption of a deposit-feeding protobranch bivalve, Nucula proxima. The largest detrital component appears to track the organic matter available for N. proxima and influence its physiological energetic budget. The animal absorbed bacteria more efficiently than detritus, but obtained less organic carbon from the bacteria. Changes in bacterial abundance were related to water temperature, but the absorption efficiency did not track bacterial abundance. Differences in ingestion rate could not be detected between 12 and 25-degrees-C, but temperatures below 12-degrees-C did decrease the pellet production rate of the animal.