The diversity of nitrogen-based dissimilatory metabolisms in anoxic waters continues to increase with additional studies to the marine oxygen deficient zones (ODZs). Although the microbial oxidation of nitrite (NO₂^–) has been known for over a century, studies of the pathways and microbes involved have generally proceeded under the assumption that nitrite oxidation to nitrate requires dioxygen (O₂). Anaerobic NO₂^– oxidation until now has been conclusively shown only for anammox bacteria, albeit only as a limited sink for NO₂^– in their metabolism compared to the NO₂^– reduced to N₂. Here, using direct experimental techniques optimized for replicating in situ anoxic conditions, we show that NO₂^– oxidation is substantial, widespread, and consistent across the ODZs of the eastern tropical Pacific Ocean. Regardless of the specific oxidant, NO₂^– oxidation rates are up to an order of magnitude larger than simultaneous N₂ production rates for which these zones are known, and cannot be explained by anammox rates alone. Higher rates of NO₂^– oxidation over reduction in anoxic waters are paradoxical but help to explain how anammox rates can be enhanced over denitrification in shallow anoxic waters (σ_θ < 26.4) at the edge of the ODZs but not within the ODZ core. Furthermore, nitrite oxidation may be the key to reconciliation of the perceived imbalance of the global fixed nitrogen loss budget.

随着对海洋缺氧区域（ODZs）的额外研究，缺氧水中基于氮的异化代谢的多样性继续增加。尽管亚硝酸盐的微生物氧化（NO ₂ ^- ）已被公知为在一个多世纪，途径和所涉及的微生物的研究假设下一般都进行亚硝酸盐氧化成硝酸盐，需要分子氧（O ₂）。厌氧NO ₂ ^-氧化直到现在已经结论性地示出仅针对厌氧氨氧化菌，虽然只作为有限水槽为NO ₂ ^-在它们的代谢相比于NO ₂ ^-还原成N ₂。在这里，用直接的实验技术原位缺氧条件下复制优化，我们表明，NO ₂ ^-氧化是巨大的，广泛的，和整个东部热带太平洋的ODZs一致。不管具体的氧化剂，NO ₂ ^-的氧化速率可达到数量级比同时使用N大一个数量级₂为其中这些区域是已知的，并且仅通过厌氧氨氧化率不能解释生产率。NO的高利率₂ ^-氧化过度还原缺氧水域矛盾，但有助于解释如何厌氧氨氧化速率可以通过在浅水水域缺氧脱氮增强（σ _θ<26.4）在ODZ的边缘，但不在ODZ核心内。此外，亚硝酸盐氧化可能是调和全球固定氮损失预算中不平衡现象的关键。