BACTERIA IN CORAL-REEF WATER TYPES - REMOVAL OF CELLS, STIMULATION OFGROWTH AND MINERALIZATION

Water samples were collected at a fringing coral reef in overlying wat er, in bottom water between corals and in crevices under coral colonie s, and analyzed for nutrient concentrations, bacterial numbers and pro duction. We found decreasing bacterial densities from overlying water through bottom water into crevices (range 9 to 2 x 10(5) ml(-1)). Bact erial specific growth was enhanced in reef crevices (range 0.005 to 0. 04 h(-1)). Although bacterial growth was enhanced, bacterial numbers w ere reduced, showing a transfer of bacterial biomass into the reef. Th e differences in bacterial numbers and growth between water types depe nded on water movement and bottom relief. Nutrients were enhanced in r eef crevices as a result of mineralization. Mineralization of bacteria removed by filter-feeders could contribute 11 and 21% to the increase in N and P, respectively, in coral reef crevices.