Macronutrients and trace metals are incorporated into phytoplankton during growth and regenerated back into the water column when phytoplankton decay, a process that contributes to the distributions of dissolved trace metals and macronutrients in depth profiles. To study this, we incubated mixed Gulf of Mexico phytoplankton assemblages and monocultures of the diatom Pseudo‐nitzschia dolorosa and the dinoflagellate Karenia brevis in the dark. Over 6 months, macronutrients (phosphate, silicic acid, nitrate + nitrite, nitrite, ammonium), chlorophyll‐a, particulate organic carbon and nitrogen, and prokaryotes were monitored alongside dissolved manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb). Results were compared to depth profiles to evaluate the role of regeneration in trace metal cycling. In contrast to water‐column distributions, silicic acid and phosphate were closely coupled in experiments containing diatoms, indicating a shared regeneration pathway. Nitrification and nitrifying prokaryotes were only observed near the end of a subset of the experiments. Of the trace metals, Cd was most tightly coupled with phosphate. Regeneration of Mn was followed by rapid drawdown, consistent with Mn‐oxide formation. Iron (Fe), Cu, and Pb typically remained low until Mn was depleted, suggesting either scavenging to Mn‐oxides or otherwise delayed regeneration of these elements. Cobalt (Co) and Ni were largely conservative, but behaved like nutrients in the experiment using more offshore water low in Cd and Zn. Although experimental conditions were limited in their representation of the water column, these incubations provide novel insight into macronutrient and trace metal regeneration in the oceans.

中文翻译：

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浮游植物衰退过程中大量营养素和微量金属的再生：一项实验研究

大量营养素和微量金属在生长过程中被纳入浮游植物中，并在浮游植物腐烂时再生回到水柱中，这一过程有助于溶解的微量金属和大量营养素在深度剖面上的分布。为了研究这个问题，我们培养墨西哥湾混合浮游植物组合和硅藻的单种拟菱形藻苦难和甲藻米氏杆菌在黑暗中。在6个月内，大量营养素（磷酸盐，硅酸，硝酸盐+亚硝酸盐，亚硝酸盐，铵），叶绿素a，颗粒有机碳和氮以及原核生物以及溶解的锰（Mn），铁（Fe），钴（Co），镍（Ni），铜（Cu），锌（Zn），镉（Cd）和铅（铅）。将结果与深度曲线进行比较，以评估再生在痕量金属循环中的作用。与水柱分布相反，硅酸和磷酸盐在含有硅藻的实验中紧密耦合，表明共有再生途径。仅在实验的一个子集即将结束时才观察到硝化和硝化原核生物。在痕量金属中，Cd与磷酸盐紧密结合。锰的再生紧随其后，与锰氧化物的形成相一致。铁（Fe），铜和铅通常保持在低水平，直到锰被耗尽为止。表明清除了Mn氧化物或延缓了这些元素的再生。钴和镍在很大程度上是保守的，但在实验中使用了更多的镉和锌含量低的离岸水，其行为像养分一样。尽管实验条件在水柱的表示上受到限制，但这些培养为海洋中的大量营养物和微量金属的再生提供了新的见识。