2016 Fiscal Year Final Research Report
The oxygen isotope anomaly of nitrate as tracer of atmospheric nitrate in marine nitrogen cycling
| Project/Area Number |
26550007
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | Tokai University |
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Principal Investigator |
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| Project Period (FY) |
2014-04-01 – 2017-03-31
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| Keywords | 硝酸 / 安定同位体 / 三酸素同位体 / 化学海洋学 |
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| Outline of Final Research Achievements |
The triple oxygen isotopic compositions of oceanic nitrate can be an useful tracer to quantify the mixing ratios of depositional nitrate within total nitrate in a water mass, because atmospheric nitrate shows large 17O anomaly due to the contribution of atmospheric ozone having large anomaly, whereas re-mineralized nitrate produced biologically shows little 17O anomaly. Determination on the triple oxygen isotopic compositions of nitrate allows us to estimate the mixing ratios of depositional nitrate within total nitrate.
To determine oxygen isotopic compositions of nitrate, nitrate must be reduced to nitrous oxide following to nitrite. Using Cu-coated Cd for reduction to nitrite allow us to save analytical time. We developed new automated analytical system for oxygen isotopic compositions of nitrate at Tokai university. We started to analyze stable isotopic compositions of oceanic nitrate during KH-14-6 of GEOTRACES cruise.
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| Free Research Field |
生物地球化学
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