Joint study on the long term variations of marine ecosystem

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1.We have exchanged information and discussion on the long-term variability of marine ecosystems with U.S.and Canadian research groups including Prof.Rothschild of University of Maryland, based on respective researches. The studies by the Japanese scientists have shown changes in reproductive patterns of sardine, replacements of dominant fish species such as sardine and anchovy around Japan, and relationships between climatic and oceanographic conditions and long-term variations in plankton and sardine in the western North Pacific ocean. On the U.S.side, the U.S.GLOBEC program have been commenced studying on Georges Bank ecosystem in the North Atlantic. It emphasizes applications and developments of new techniques to observe and measure biological processes in situ, developments of monitoring methodology, and modelling. Japan seems to get behind U.S.in such technology. For the future study, we should introduce and develop new technology in conjunction with U.S.We recognized the signifi … More cance of studies on ecosystem dynamics in the seas adjacent to Japan where several pelagic fishes replace each other as dominant under oceanic conditions affected basically by both the Kuroshio and the Oyashio unlike the North Atlantic ocean.2.Application of neural networks in which Prof.Rothschild was also interested was examined for analysis and prediction of decadal change in sardine abundance, using two decadal data on climatic, oceanographic and zooplankton conditions. Predictability of sardine abundance from environmental condition was shown.3.OSSE (Observation System Simulation Experiments) -GLOBEC meeting was held at La Paz in Mexico. In this meeting, AMOS (Advanced Modeling and Observation Systems) study in GLOBEC International focused its study field on North Atlantic and Kuroshio extension. As case studies, modelling studies were conducted to investigate the effects of interaction between two warm-core rings on the phytoplankton distribution using a quasi-geostrophic reduced-gravity model and OGCM.4.Through the discussion and information exchange with scientists of the University of Maryland, both sides agreed to start appropriate cooperation projects in near future. The main purposes will be to clarify the turnover of high-molecular-weight organic compounds in the ocean, because this is important to understand the long-term change of marine environments. Considering the recent works at both sides, we begin with the research on the process at interface with special emphasis on the behavior and function of microbes on surfaces. Less