A BUDGET OF CARBONATE FRAMEWORK AND SEDIMENT PRODUCTION, KAILUA BAY,

ABSTRACT: Sediments of the bay and coastal plain of Kailua (Oahu, Hawaii) are. 90 % biogenic carbonate produced by destruction of primary reef framework (coral and encrusting coralline algae) and by direct sedimentation through the biological activity of calcifying or-ganisms (the green alga Halimeda, the branching coralline alga Poro-lithion gardineri, molluscs, and benthic foraminifera). Field measure-ments of benthic community structure, gross carbonate production, bioerosion, and direct sedimentation in 17 physiographic zones in Kai-lua Bay are used to calculate modern calcareous sediment production rates in the 12 km2 fringing reef system. Total gross carbonate productivity by corals and encrusting coralline algae (based on mapped percent cover and known growth rates) occurs at an average rate of 1.22 (6 0.36) kg m22 y21 over hard substrates of the reef platform, corresponding to 0.8 (6 0.2) mm y21 (using a bulk density of 1.48 g cm23, the average of coral and coralline algae)