The geochemical behavior of molybdenum (Mo) in the oceans is closely linked to the presence of sulfide species in anoxic environments, where Fe availability may play a key role in the Mo scavenging. Here, we show that Mo(VI) is reduced in the presence of particulate organic matter (represented by sulfate‐reducing bacteria). Molybdenum was immobilized at the surface of both living cells and dead/lysed cells, but not in cell‐free control experiments. Experiments were carried out at four different Mo concentrations (0.1 to 2 mm) to yield cell‐associated Mo precipitates with little or no Fe, consisting of mainly Mo(IV)‐sulfide compounds with molecular structures similar to Mo enzymes and to those found in natural euxinic sediments. Therefore, we propose that Mo removal in natural sulfidic waters can proceed via a non‐Fe‐assisted pathway that requires particulate organic matter (dead or living sulfate‐reducing bacteria). This pathway has implications for global marine Mo cycling and the current use of Mo‐based proxies for paleo‐environmental investigations.

中文翻译：

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在硫化条件下钼与有机颗粒结合的证据。

海洋中钼（Mo）的地球化学行为与缺氧环境中硫化物的存在密切相关，在缺氧环境中，Fe的可用性可能在清除Mo中起关键作用。在这里，我们表明，在存在颗粒有机物（以硫酸盐还原菌表示）的情况下，Mo（VI）会还原。钼固定在活细胞和死/裂解细胞的表面，但在无细胞对照实验中没有。实验在四种不同的Mo浓度（0.1至2 m m）产生几乎没有Fe的与细胞相关的Mo沉淀物，主​​要由分子结构类似于Mo酶和天然富氧沉积物中发现的Mo（IV）-硫化物的化合物组成。因此，我们建议在天然硫化水中去除Mo可以通过非Fe辅助途径进行，该途径需要颗粒有机物（死的或活的减少硫酸盐的细菌）。该途径对全球海洋Mo循环以及当前基于Mo的代理进行古环境调查具有重要意义。