Carbon to chlorophyll-a ratio in modeling long-term eutrophication phenomena

Carbon to chlorophyll-a ratio (CCHL) is formulated based on the assumption that adaptive changes in carbon to chlorophyll occur so as to maximize the specific growth rate for ambient conditions, including solar radiation and water temperature. With the dynamic CCHL, an unsteady two-layered, two-dime nsional eutrophication numerical model for density stratified coastal water s has been developed. Saturated light intensity (Is) is determined as weigh ted average of the light intensity for previous three days to incorporate l ight acclimation by phytoplankton. The bottom water anoxic condition during summer in Tolo Harbour, Hong Kong is successfully reproduced by the presen t method. Otherwise, the simulation with a constant CCHL gave a wrong resul t. (C) 1998 IAWQ Published by Elsevier Science Ltd. All rights reserved.