9633784 YOUNG Most deep-sea animals are capable of continuous reproduction, but a few have annual reproductive cycles. This is a paradox, since the environmental cues used by shallow-water marine animals for synchronizing their reproductive cycles (e.g., changing daylength, lunar period, or increasing temperature) are generally absent from the deep sea. In many parts of the world ocean, however, there is a seasonally variable cycle of detrital rain. For example, in much of the North Atlantic, a seasonal pulse of phytoplankton arrives at the sea floor several weeks after the surface phytoplankton bloom. It has been proposed that deep-sea animals use this pulse either to entrain their reproductive cycles, or to provide the energy needed for a reproductive event. To date, however, there is no experimental evidence in support of this hypothesis. In this project, laboratory experiments will be used to determine if several species of large bathyal invertebrates can shift their reproductive seasons or increase their reproductive output in response to phytodetrital pulses. For comparative purposes, both seasonal and aseasonal breeders will be used, and also species with fast and slow mechanisms of egg production. ***
