Abstract
In late years, biomanipulation technology attracts attention as one of the methods to purify the quality of the water. The biomanipulation is methods to introduce a creature, but this method has a danger to collapse existing ecosystems. Therefore the environmental assessment to perform biomanipulation is important. This experiment was carried out to investigate the basic ecosystemic impact statement of the water quality improvement of the biomanipulation. It performed the basic environmental assessment which focused its attention on an ecosystem function as P/R ratio using microcosm. The microcosm system was made from producer, predator and decomposer. The producer is micro alga. The predator is micro animal which are ciliata, rotifer and oligochaeta. The decomposer is bacteria taking in organic matter. In this experiment, Aeolosoma hemprichi (top predator) and Cyclidium glaucoma (primary predator) were introduced into microcosm as the introduced species for bioremediation. As results, Chlorella sp. and Scenedesmus sp. decreased in the flask which introduced Aeolosoma hemprichi as the top predator. But, they didn't decrease in the flask which introduced Cyclidium glaucoma. The top predator may keep a proper population of the micro alga. In the case of top predator introduction, a possibility that could solve water-bloom was demonstrated.
