FECAL PELLET PRODUCTION AND SEDIMENT REWORKING POTENTIAL OF THE POLYCHAETE HETEROMASTUS-FILIFORMIS SHOW A TIDE DEPENDENT PERIODICITY

The sediment reworking potential of Heteromastus filiformis (a capitellid polychaete) was determined in a laboratory mesocosm by collecting and counting fecal pellets deposited on the sediment surface at 6-hour intervals over several simulated tidal cycles. Pellet production rates showed a marked 6-hour periodicity. Production was highest during the flooding and decreased during the ebbing tide. In the absence of a simulated tidal cycle, there was no periodicity in pellet production. With an annual mean population density of 1200 individuals/m2 in the Jadebusen Bay, Wadden Sea, the quantity of sediment reworked by H. filiformis is about 175 ml/m2/day or 64 l/m2/year, which is approximately a deep-sediment layer of 6 cm, transported to the surface annually . Pellet production by Heteromastus contributes substantially to the recycling of detritus and nutrients in the Wadden Sea, especially in areas with high population densities.