AGE, VIABILITY, AND VERTICAL-DISTRIBUTION OF ZOOPLANKTON RESTING EGGS FROM AN ANOXIC BASIN - EVIDENCE OF AN EGG BANK

Seabed cores to a sediment depth of 24 cm were obtained by divers from an anoxic basin in the Pettaquamscutt estuary. The cores were processed to determine the age, viability, and vertical distribution of zooplankton resting eggs in the bottom sediments. Zooplankton eggs were found throughout the upper 24 cm. Copepod nauplii emerged from sediments as deep as 22 cm that were incubated in the laboratory. Based on Pb-210 analyses of the sediments, we calculated that the viable eggs ranged in age from < 1 yr in the surface layers of the seabed to > 40 yr in the deepest portions. These data provide conclusive evidence for the existence of an egg bank.