微生物亚硝酸盐消耗者诱导的海洋最低氧区亚硝酸盐积累

近日，美国宾夕法尼亚大学Xin Sun团队研究了微生物亚硝酸盐消耗者诱导的海洋最低氧区亚硝酸盐积累。相关论文于2025年11月13日发表在《自然—地球科学》杂志上。

亚硝酸盐是好氧和厌氧氮循环途径的关键中间体。虽然亚硝酸盐很少在海洋中积累，但在缺氧区亚硝酸盐的浓度达到微摩尔，其原因尚不清楚。微生物负责亚硝酸盐的生产和消耗，它们的相互作用是由有机基质向缺氧水体的动态供应所推动的。

研究组提出了一个机制生态系统模型来研究微生物群落对有机质供应随时间变化的反应。他们的研究结果表明，亚硝酸盐氧化细菌尽管消耗亚硝酸盐，但通过与其他微生物（主要是反硝化菌）的相互作用，促进了这种积累。好氧亚硝酸盐氧化细菌利用亚硝酸盐还原反硝化菌产生的亚硝酸盐，竞争并抑制亚硝酸盐还原反硝化菌。在所有亚硝酸盐被消耗之前，氧气限制了亚硝酸盐氧化细菌，导致亚硝酸盐积累。

在涡旋解析的三维模型中，微生物活动在时间上的这种变化表现为时间和空间的变化，与观测到的亚硝酸盐深度剖面、其通量和亚硝酸盐氧化细菌的丰度密切匹配。这些结果揭示了一种驱动亚硝酸盐积累的机制，它维持了缺氧区生物有效氮的存量，表明微生物在精细尺度洋流中的相互作用决定了氮的命运。

附：英文原文

Title: Nitrite accumulation in marine oxygen minimum zones induced by microbial nitrite consumers

Author: Sun, Xin, McCoy, Daniel, Xu, Liang, Buchanan, Pearse J., Zakem, Emily J.

Issue&Volume: 2025-11-13

Abstract: Nitrite is a key intermediate in both aerobic and anaerobic nitrogen-cycling pathways. Although it rarely accumulates in the ocean, nitrite reaches micromolar concentrations in anoxic zones for reasons that remain unclear. Microorganisms are responsible for the production and consumption of nitrite, and their interactions are fuelled by the dynamic supply of organic substrates to anoxic waters. Here we use a mechanistic ecosystem model to study the microbial community response to such variations in the supply of organic matter over time. Our results demonstrate that nitrite-oxidizing bacteria, despite consuming nitrite, contribute to this accumulation through interactions with other microorganisms, mainly denitrifiers. Aerobic nitrite-oxidizing bacteria capitalize on the nitrite produced by nitrate-reducing denitrifiers, outcompeting and suppressing nitrite-reducing denitrifiers. Oxygen limits nitrite-oxidizing bacteria before all the nitrite is consumed, leading to nitrite accumulation. In an eddy-resolving, three-dimensional model, this shift in microbial activity in time manifests as shifts in both time and space, closely matching observed depth profiles of nitrite, its fluxes and the abundance of nitrite-oxidizing bacteria. These results reveal a mechanism driving nitrite accumulation, which maintains the standing stock of bioavailable nitrogen in anoxic zones, demonstrating that microbial interactions within fine-scale ocean currents dictate the fate of nitrogen.

来源：小柯机器人

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