Project Title: Recruitment Dynamics of Deep-Sea Coral

Principal Investigators: L. Mullineaux, Woods Hole Oceanographic Institution and J. Adkins, California Institute of Technology

The objective of this study is to determine how coral communities form and persist in submarine canyons and on seamounts, in order to understand the dynamics of the component populations and their susceptibility to disturbance. To accomplish this, we need to know where and when communities form, how often they are recolonized, and whether subsequent colonists are supplied by the local populations or immigrate from remote sources. Recruitment processes will be studied directly through time-series monitoring of the appearance of new individuals in an environment, and indirectly through analysis of the age-structure of established individuals. Ages of live corals will be determined by radiometric dating, using 210Pb; in addition 238U-234U230 Th dating will be conducted on older individuals to extend the mapping of age distributions in larger "patches" of coral recruitment. Specimens and images will be collected from coral communities in Georges Bank submarine canyons and on proximate New England seamounts, using the submersible Alvin and a towed camera system. These studies have been designed to coordinate with complementary studies of the distribution and environmental affinities of the same coral species. Coral populations that form aggregations infrequently, are recolonized rarely, and are self-recruiting (i.e., closed) are likely to be much more susceptible to disturbance than those that develop and repopulate aggregations frequently through larval exchange with remote populations.