2019 Fiscal Year Final Research Report
Quantifying denitrification rates at the sediment-water interface using triple oxygen isotopes of dissolved nitrate as tracer
| Project/Area Number |
18K19853
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Review Section |
Medium-sized Section 63:Environmental analyses and evaluation and related fields
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| Research Institution | Nagoya University |
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Principal Investigator |
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| Project Period (FY) |
2018-06-29 – 2020-03-31
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| Keywords | 脱窒速度 / 硝化速度 / 窒素循環 / 水－堆積物インターフェース / 硝酸 / 三酸素同位体組成 / 新培養法 |
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| Outline of Final Research Achievements |
In this study, we developed a new method for quantifying the denitrification rate in vitro using the triple oxygen isotopic compositions of nitrate as tracer. Our newly developed method eliminates the need to shield the culture vessel from the air. As a result, existing samplers, such as flux chamber for observing in situ fluxes of nitrogen at the sediment-water interface, core samplers for collecting surface sediments, sediment traps for collecting sediment particles, plankton net for collecting suspended particles, etc.) can now be used as a culture system. Our method has made it possible to culture sediments with simple operations with changing the in-situ redox environment as little as possible, and to obtain a highly accurate denitrification rate.
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| Free Research Field |
生物地球化学
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| Academic Significance and Societal Importance of the Research Achievements |
近代以降の人間活動の拡大に伴って、地球表層環境中の固定態窒素（一般の植物が利用できる窒素）量は過剰となりつつあり、富栄養化や生態系の攪乱など様々な環境問題を引き起こしている。この固定態窒素は、海底堆積物や沈降粒子、貧酸素水塊などの嫌気的環境下で、脱窒によって除去されることから、脱窒速度の値やその経年変化は、環境問題の対策を考える上で重要な数字となる。本手法を用いて求められた確度の高い脱窒速度データが蓄積されることで、正確な固定態窒素の収支やその経年変化を様々な時空間スケールで見積もれるようになるので、地球環境研究一般の発展に大いに貢献する。
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