In the areas of structure and biota analysis of communities and examination of the dispersal of chemosynthetic communities, we continued our survey on chemosynthetic communities in Sagami Bay, the Okinawa trough, and the Ogasawara sea area. We also conducted a survey on the hydrothermal vent community found at the Daini Kasuga seamount in the north Mariana trough, an important location for studies involving the biogeography of the western Pacific. At the Daini Kasuga seamount, we discovered a hydrothermal vent community at the peak of the seamount, at a depth of approximately 400 meters. The biota resembled that found in the Kaikei seamount of the Ogasawara region. We also performed a Deep Tow survey of the cold-seep communities off shore of Kushiro in Hokkaido, and discovered a chemosynthetic community containing Calyptogena at a depth of 1,200 meters. This may provide valuable clues for solving the dispersion process of Calyptogena. In our study of the relationship between environmental factors and ecotypes, we conducted research on the breeding habits of Calyptogena and in situ experiments such as growth rate analyses on Bathymodiolus. We also conducted germination experiments on Vestimentifera in Kagoshima Bay. In our search for valuable resources, we looked for substances in Calyptogena and Vestimentifera and discovered a substance that suppresses the side effects of antitumoral medication in the organic solvent extract of Calyptogena.