Minh Hang, N. T., Araki, H., Cao Don, N., Yamanishi, H. and KOGA, K., 2007. Hydrodynamics and Water Quality Modeling for the Ecosystem of the Ariake Sea, Kyushu, Japan. Journal of Coastal Research, SI 50, 800 – 804. Gold Coast, Australia, ISSN 0749.0208

In this study, a water quality model was developed to model the ecosystem in the Ariake Sea in Kyushu, Japan. The model simulates the dynamic of phytoplankton, zooplankton, nutrients, organic detritus and dissolved oxygen. Through the observed data and the simulated results, the characteristics of the sea were examined. We found that the concentrations of nutrients and other water quality constituents were high in summers, where as, dissolved oxygen concentration was low during the summer months, then elevated during the winter months. Moreover, high concentrations of nutrients and Chlorophyll-a were found in the inner part of the sea during the summer periods, when high discharge loadings from rivers and high release and resuspension from the bottom mud were predominant. Sensitivity analysis shows that the increase of nutrient loads would significantly result in the increase of phytoplankton biomass, especially during summer to early winter. The effects of loads reductions will be most pronounced in the river mouth areas.