Abstract
Dissolved oxygen (DO) mainly declines in the inner part of the Ariake Sea during summer. Low DO is frequently observed in a short period and in the small area together with red tides and/or density stratification. Since many researches on the decrease in DO in the Ariake Sea were conducted only in the limited period and area, the study on the change of DO in long-term and over the wide area becomes necessary. In this study, a finite volume model is applied as an analysis tool to determine phenomena of the long-term change of DO in the Ariake Sea. The simulated results reveal that the level of DO in the summer of the 1970s is lower than that in the recent decade. It is pointed out that algal production due to the disposal of human excrement in the Ariake Sea is the major cause of low DO in the 1970s.
