Biogeochemical implications of global imbalance between the rates of marine dinitrogen (N2) fixation and denitrification have spurred us to understand the former process in the Arabian Sea, which contributes considerably to the global nitrogen budget. Heterotrophic bacteria have gained recent appreciation for their major role in marine N budget by fixing a significant amount of N2. Accordingly, we hypothesize a probable role of heterotrophic diazotrophs from the 15N2 enriched isotope labelling dark incubations that witnessed rates comparable to the light incubations in the eastern Arabian Sea during spring 2010. Maximum areal rates (8 mmol N m-2 d-1) were the highest ever observed anywhere in world oceans. Our results suggest that the eastern Arabian Sea gains ~92% of its new nitrogen through N2 fixation. Our results are consistent with the observations made in the same region in preceding year, i.e., during the spring of 2009.
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机译：海洋二氮（N2）固定和反硝化速率之间全球失衡的生物地球化学影响促使我们了解阿拉伯海的前一过程，这对全球氮预算有很大贡献。异养细菌通过固定大量的N2在海洋氮预算中的主要作用而获得了最近的赞赏。因此，我们假设富含15N2的同位素标记的黑暗孵化中的异养重氮菌可能发挥了作用，其见证的速率与2010年春季在阿拉伯海东部的光孵化相当。最大面积速率（8 mmol N m-2 d-1）为世界海洋中任何地方观测到的最高水准。我们的结果表明，阿拉伯东部海域通过N2固定获得了约92％的新氮。我们的结果与上一年（即2009年春季）在同一地区的观察结果一致。
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