2005 Fiscal Year Final Research Report Summary
Modeling of global biogeochemical cycles explicitly representing marine ecosystem
| Project/Area Number |
15510001
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | Hokkaido University |
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Principal Investigator |
YAMANAKA Yasuhiro Hokkaido Univ., Faculty of Environmental Earth Sci., Asso.Prof., 大学院・地球環境科学研究院, 助教授 (40242177)
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| Co-Investigator(Kenkyū-buntansha) |
KISHI Michio Hokkaido Univ., Faculty of Fisheries, Prof., 大学院・水産科学研究院, 教授 (90214767)
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| Project Period (FY) |
2003 – 2005
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| Keywords | marine ecosystem / modeling / biodiversity / global warming / biogeochemical cycles / climate changes / plankton |
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| Research Abstract |
We developed a marine ecosystem model including nine groups of plankton explicitly representing subarctic and subtropical species, and simulated the observed seasonal changes. We found that the seasonal change in sea surface temperature brings about symbiosis of both subarctic and subtropical species at a specific site. In other words, the seasonal change adapts a specific species to environments from subarctic to subtropical regions. At typical two sites, A7 in the subarctic and B1 in the subtropical regions, our model well simulated the observed seasonal changes of group biomasses for phytoplankton and zooplankton.
Hindcast experiment from 1948 to 2002 simulated by our 3-D global ecosystem model, including five groups, successfully reproduced the regime shift of primary production and zooplankton biomass in 1970s, and also simulated group shifts between large and small zooplankton and partial pressure of carbon dioxide associated with interannual variations.
Simulation by a 3-D regional ecosystem model showed that major phytoplankton is determined by nutrient dependency of photosynthesis in the subtropical region and by grazing preference of copepods in the subarctic regions. Based on the global warming simulation conducted by Center for Climate System Research in Tokyo University and National Institute for Environmental Studies, we studied an impact of global warming on marine ecosystem at the end of this century. We found an impact of global warming does not uniformly occur but occurs in the specific region, the mixed water region, between the subarctic and subtropical regions. Especially, large reduction of primary production and major group at the second half of the spring bloom, growth season of small pelagic fish, are caused by global warming. This study tells us that global warming will bring about large reduction of fish resource.
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