During the past 10 years, I have been working on several multidisciplinary projects concerning IGBP-TEMA-MEXT, the creative new research program of MEXT on biodiversity, JSPS-Research for the Future Program, and the RIHN project of Lake Biwa-Yodo River Water shed' On the basis of these experiences, I will promote the undertaking of several projects in our program on ecosystem modeling. Two important roles could be emphasized in our program: establishment of terrestrial and marine ecosystem models with close connection to GCM, and clarification of the mechanism of ecosystem changes focusing on the interactive cycle between man and nature. My research field is isotope biogeochemistry and ecology.