NUMERICAL SIMULATION ON HABITAT OF CORAL REEF IN A BAY

Abstract

Coral reef inOkinawa Island is decreasing dramatically due to risingwater temperature, redsoil run-off and seriousproliferationof crownof thorns starfish. In a semi-closed bay such asNagurabay inIshigaki Island, the eutrophication caused by the nutrient supply from river can be a contributing factor ofthe coral decrease. The impact of thered soil run-offand the eutrophicationonhabitat of coral reef isevaluated bynumerical simulation using 3D ecological model (ELCOM-CAEDYM) in this study. The results of numerical calculations suggest that the eutrophication, whichcauses the extinctionof coralseedstock due to algal propagation, canoccur during prevailing south wind and the averageconcentrations of nutrients at the coastal area in Nagura bay become higher than those at other points inIshigaki Island.