Research Subjects


From genes to ecosystems and from ecosystems to genes :Interactions among microbes and humans in aquatic ecosystems such as ocean coastal area, lakes, ponds, rivers, aquatic microcosms, aquatrons, and Symbiotron, have been analyzed focusing on;

  1. effects of environmental change on interactions between pathogens and humans

  2. the relationship between biological interactions and horizontal gene transfer

  3. the relationship between species diversity and ecosystem functions
  4. ecology of virus and bacteria causing cyanobacteria Microcystis mortality.

Most Significant Contributions

  1. We were the first to demonstrate the existence of the diversity of virus-like agents killing Microcystis aeruginosa in a shallow hyper-eutrophic pond in Japan.This was done without specific virus isolation, based upon its genomic size fraction.

  2. We found that microbes involved in horizontal gene transfer among bacteria in aquatic ecosystem. They promote horizontal gene transfer frequency either positively or negatively depending on the species.
  3. We found that water current intruding into a bay play a role to supply nutrients to the epilimnion from the see bottom. This ensures a high primary production, leading to fishery farming. This research became a trigger to stimulate the study on the interactions among water current , nutrients and phytoplamkton dymanics.

  4. We clarified the environmental factors which involved in excystment of dinoflagellates in freshwater ecosystem.

  5. We pioneered the study on community dynamics by using microcosms which were model ecosystems, combined with computer simulation models. We revealed that stable steady state of community was obtained by reduction in the strength of interactions each other in the whole system.