Distributions of pigments in reef sediments, contribution of phytoplankton to organic matter budget in coral reef

The temporal distributions of pigment on bio-genic calcareous and terrigenic reef sediments, chlorophyll a, chlorophyll b, chlorophyll c, fuco- xanthin, and porphine concentrations were mea- sured monthly in two sediment columns (0 - 15 cm) for one year. Pigment concentrations increased significantly during winter (November-April) in both sediment types particularly in the upper layers of the sediments. Phytoplankton contri-butions to organic matter were found to be 8 +/- 3 and 6 +/- 2% in calcareous and terrigenous se-diments respectively. The accumulation and the successive degradation of phytoplankton de-tritus to inorganic nutrients in calcareous sand may partly sustain the productivity of the coral reef communities which live in nutrient-poor environments.