| Project/Area Number |
26870155
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Environmental dynamic analysis
Geochemistry/Cosmochemistry
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| Research Institution | The University of Tokyo |
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Principal Investigator |
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| Project Period (FY) |
2014-04-01 – 2016-03-31
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| Project Status |
Completed (Fiscal Year 2015)
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| Budget Amount *help |
¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
Fiscal Year 2015: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2014: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Keywords | サンゴ骨格 / 窒素同位体比 / カリブ海 / 窒素固定 / 更新世 |
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| Outline of Final Research Achievements |
Oceanic nitrogen fixation is important as new nitrogen in oligotrophic oceans and balances with denitrification in global nitrogen cycle. The historical changes of nitrogen fixation rate in North Atlantic Ocean have been discussed in seasonal scale variation using modern observations and in millenia-scale variation using sediment cores in geological time scales. However, the decadal to centennial scale variation of nitrogen fixation with this global warming condition is still unknown. We use a new 94-year record of annual nitrogen isotopes in coral skeletons from Little Cayman Island, Caribbean Sea. The 94-year nitrogen isotope record in Caribbean coral revealed the change in nitrogen fixation correlated with multi-decadal temperature variation and sea level change in Atlantic Ocean. Reconstructed nitrogen fixation also showed the decreasing trend led by global warming. We apply nitrogen isotope proxy to coral fossils from paleo warming state, MIS5e in Caribbean Sea.
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