My research interests are plankton ecology in lakes and oceans. Several research topics are described below. 1) Top-down and bottom-up control in plankton food web 2) Crowding effect on energy allocation and gene expression in Daphnia magna 3) Long-term trend of crustacean zooplankton in Lake Biwa 4) Effects of internal wave on the pelagic ecosystem in Lake Biwa 5) Novel lake ecosystem management by sustainable harvesting and effective utilization of aquatic weed biomass 6) Effects of nutrient imbalance on biodiversity of planktonic creatures 7) Symbiotic bacterial community in zooplankton 8) Phosphate dynamics related to fish production in Lake Biwa