| Budget Amount *help |
¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2014: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2013: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2012: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
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| Outline of Final Research Achievements |
A marine ecosystem model that incorporates nitrous oxide (N2O) production processes (i.e., ammonium oxidation during nitrification and nitrite reduction during nitrifier denitrification) and N isotopomers was developed to estimate the sea-air N2O flux and to quantify N2O production processes. This model was applied to surface water at two contrasting time series sites, a subarctic station (K2) and a subtropical station (S1) in the western North Pacific. The model was validated with observed N concentration and N isotopomer datasets, and successfully simulated the higher N2O concentrations. The annual mean N2O emissions were estimated to be 32.3 mgNm－2yr－1 at K2 and 2.7 mg Nm－2yr－1 at S1. The results of case studies based on this model suggested that N2O was mainly produced via ammonium oxidation at K2 but was produced via both ammonium oxidation and nitrite reduction at S1.
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