Abstract
In order to make clear the material flow mechanism and the eco-system in the northern region of Kagoshima Bay, we firstly investigated the seasonal change in the water quality and phytoplankton composition utilizing the observational results. Then, we constructed a lower-trophic level model on the basis of the observation and investigated the material flow mechanism. As a result, the following findings were obtained; 1) The biomass of Bacillariophyceae is dominant among various phytoplankton groups through a year, 2) The lower-trophic ecosystem model constructed can reproduce well the seasonal change of water quality and phytoplankton biomass, 3) The change in DO near the water surface is controlled mainly by the net primary production.
