Biological and geological processes at the shelf edge investigated with submersibles

Studies of living reefs along the shelf edge off easternFlorida and the Bahamas suggest the interrelation of physical,biological, and geological processes. JOHNSON-SEA-LINKsubmersibles were used to sample corals and sediment with amanipulator or by lock-out diving. Videotape and 35 mm cameras,CTD system, and transmissometer were used to document the dives.Sediment traps, light meters, time-lapse camera, thermographs, andcurrent meters were deployed and recovered. A 222 km long reefsystem of discontinuous pinnacles capped with living and deadOculina coral was studied off Florida. Upwelling may contribute togrowth and community structure of the reef system. Growth rates ofthe coral averaged 1.6 cmjyr and the coral harbors diverse faunalassemblages. Each pinnacle produces carbonate sediment and trapsmud sized particles. Sand and gravel particles are not transportedfar from the reefs. On the margin of Little Bahama Bank sedimenttraps were also deployed to study sediment transport through reefnotches from shallow to deep water. Average sediment flux over theedge of the wall was 1.34 kg notch-1 yr-1.Studies of living reefs along the shelf edge off easternFlorida and the Bahamas suggest the interrelation of physical,biological, and geological processes. JOHNSON-SEA-LINKsubmersibles were used to sample corals and sediment with amanipulator or by lock-out diving. Videotape and 35 mm cameras,CTD system, and transmissometer were used to document the dives.Sediment traps, light meters, time-lapse camera, thermographs, andcurrent meters were deployed and recovered. A 222 km long reefsystem of discontinuous pinnacles capped with living and deadOculina coral was studied off Florida. Upwelling may contribute togrowth and community structure of the reef system. Growth rates ofthe coral averaged 1.6 cmjyr and the coral harbors diverse faunalassemblages. Each pinnacle produces carbonate sediment and trapsmud sized particles. Sand and gravel particles are not transportedfar from the reefs. On the margin of Little Bahama Bank sedimenttraps were also deployed to study sediment transport through reefnotches from shallow to deep water. Average sediment flux over theedge of the wall was 1.34 kg notch-1 yr-1.