Abstract
Degradation characteristics of blue green alga, Microcystis viridis producing toxic substance Microcystin by Mastigophora, Monas guttula were examined using an aquatic large scale microcosm. The viable cells of M. viridis was effectively predated and degraded by the small flagellate within a wide water temperature range from 20°C to 30°C. In the removal effects of several important water parameters in eutrophicated waters, the removals of chlorophyll-a and particle COD originated from M. viridis were 90% and 80%, respectively in a week. Moreover, the toxic substance, Microcystin RR, YR and LR were perfectly degraded within a short time. It was suggested that microanimals such as small flagellate played an important role for the disappearance of water bloom formed by Microcystis in eutrophicated lake.
