Within oxygen minimum zones, anaerobic processes transform bioavailable nitrogen (N) into the gases dinitrogen (N₂) and nitrous oxide (N₂O), a potent greenhouse gas. Mesoscale eddies in these regions create heterogeneity in dissolved N tracers and O₂ concentrations, influencing nonlinear N cycle reactions that depend on them. Here, we use an eddy-resolving model of the Eastern Tropical South Pacific to show that eddies enhance N₂ production by between 43% and 64% at the expense of reducing N₂O production by between 94% and 104% due to both the steep increase of progressive denitrification steps at vanishing oxygen, and the more effective inhibition of N₂O consumption relative to production. Our findings reveal the critical role of eddies in shaping the N cycle of oxygen minimum zones, which is not currently represented by coarse models used for climate studies.

中文翻译：

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中尺度涡流变化增强了固定氮损失并抑制了最低氧区域中一氧化二氮的产生

在氧气最低区内，厌氧过程将生物可利用的氮 (N) 转化为二氮 (N ₂ ) 和一氧化二氮 (N ₂ O)（一种强效温室气体）。这些区域的中尺度涡流在溶解的 N 示踪剂和 O ₂浓度中产生不均匀性，影响依赖于它们的非线性 N 循环反应。在这里，我们使用东热带南太平洋的涡旋解析模型表明，涡流将 N ₂产量提高了 43% 到 64%，但代价是 N ₂ O 产量减少了 94% 到 104%，这是由于在氧气消失时渐进反硝化步骤急剧增加，并且相对于产量更有效地抑制N ₂ O消耗。我们的研究结果揭示了涡流在塑造氧气最低区的氮循环中的关键作用，目前用于气候研究的粗略模型尚未体现这一作用。