Insight into nitrous oxide production processes in the western North Pacific based on a marine ecosystem isotopomer model
Insight into nitrous oxide production processes in the western North Pacific based on a marine ecosystem isotopomer model
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DOI：
10.1007/s10872-015-0308-2
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发表时间：
2016-02
影响因子：
2.3
通讯作者：
C. Yoshikawa;Hitomi Abe;M. N. Aita;F. Breider;Keichi Kuzunuki;S. Toyoda;N. Ogawa;Hisami Suga
中科院分区：
文献类型：
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作者：
C. Yoshikawa;Hitomi Abe;M. N. Aita;F. Breider;Keichi Kuzunuki;S. Toyoda;N. Ogawa;Hisami Suga
一个海洋生态系统模型，包括一氧化二氮（N2 O）的生产过程（即，开发了硝化过程中的铵氧化和硝化细菌反硝化过程中的亚硝酸盐还原）和N同位素来估计海-气N2 O通量并量化N2 O产生过程。该模型被应用到水以上的深度为220米，在两个对比的时间序列站点，一个亚北极站（K2）和一个亚热带站（S1）在西北太平洋。利用实测的N浓度和N同位素数据对模型进行了验证，结果表明，与S1相比，K2的N2 O浓度、δ 15 N值和N2 O的立地偏好值均较高。K2的年平均N2 O排放量估计为32.3 mg N m− 2 year − 1，S1为2.7 mg N m− 2 year − 1。基于该模型的案例研究结果估计，硝化过程中原位生物N2 O产生与硝酸盐产生的比率在K2为~ 0.22%，在S1为~ 0.06%。也有人建议，N2 O主要是通过铵氧化在K2，但通过铵氧化和亚硝酸盐还原在S1产生。K2处的大部分（~ 80%）铵氧化由地下水中的古菌进行。同位素示踪培养实验使用古细菌活性抑制剂支持这一假设。
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 water above the depth of 220 m 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 data sets, and successfully simulated the higher N2O concentrations, higher δ15N values, and higher site preference values for N2O at K2 compared with S1. The annual mean N2O emissions were estimated to be 32.3 mg N m−2year−1at K2 and 2.7 mg N m−2year−1at S1. The results of case studies based on this model estimated the ratios of in situ biological N2O production to nitrate production during nitrification to be ~0.22 % at K2 and ~0.06 % at S1. It is also suggested that N2O was mainly produced via ammonium oxidation at K2, but was produced via both ammonium oxidation and nitrite reduction at S1. A large fraction (~80 %) of the ammonium oxidation at K2 was carried out by archaea in the subsurface water. Isotope tracer incubation experiments using an archaeal activity inhibitor supported this hypothesis.