アラブ海における窒素喪失の主なプロセスとしての脱窒化
B B Ward1, A H Devol, J J Rich
1Department of Geosciences, Princeton University, Princeton, New Jersey 08544, USA. bbw@princeton.edu
Nature
|September 4, 2009
まとめ
アナモックスではなくデニトリフィケーションが,アラビア海における窒素損失の主な原因である.
科学分野:
- 海洋微生物生態学について
- バイオジオケミカルサイクルとは
- 海洋学 海洋学とは
背景:
- 海洋の一次生産は,固定窒素によって制限されることが多い.
- 窒素の損失は,脱窒化と無酸素アンモニア酸化 (anammox) によって発生します.
- 最低酸素ゾーン (OMZ) は,海洋の窒素損失の重要な場所です.
研究 の 目的:
- OMZにおけるデニトリフィケーションとアナモックス率を定量化する.
- アラブ海OMZにおける支配的な窒素喪失経路を決定する.
- アラブ海と東熱帯南太平洋のOMZにおける窒素循環を比較する.
主な方法:
- デニトリフィケーションとアナモックス速度のインシットー測定.
- デニトリファインとアナモックスバクテリアの豊富さの定量化.
- 2つの独立した同位体インキュベーション方法の使用.
主要な成果:
- アラブ海OMZにおけるN(2) 生産の87-99%はデニトリフィケーションによる.
- アナモックスは,東熱帯南太平洋OMZにおけるN(2) 損失を主導した.
- 窒素化細菌は,両方のOMZでアナモックス細菌を上回った.
結論:
- アラブ海OMZにおける窒素喪失の主な要因は脱窒化である.
- デニトリフィケーションとアナモックスの相対的な重要性は,地理的に異なります.
- デニトリフィケーションは,海洋の窒素予算において,世界的に重要な役割を果たしています.
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