Trace metals (TMs) manganese (Mn), cobalt (Co), and aluminium (Al) have important geochemical and biological roles in the ocean. Here, we present full depth profiles of dissolved (d) and particulate Al, Mn, and Co along the latitude of 40 °S in the South Atlantic Ocean from the GEOTRACES GA10 cruises that operated in austral spring 2010 and summer 2011. The region is characterized by enhanced primary productivity and forms a key transition zone between the Southern Ocean and South Atlantic Subtropical Gyre. The mean concentrations of dAl, dCo, and dMn (±standard deviation) were 3.36 ± 2.65 nmol kg, 35.3 ± 17.6 pmol kg, and 0.624 ± 1.08 nmol kg, respectively. Their distributions in surface waters were determined by external sources and complex internal biogeochemical processes. Specifically, surface ocean dCo was controlled by the interplay between phytoplankton uptake, remineralization and external inputs; dMn was likely determined by the formation and photoreduction of Mn-oxides; and dAl was supplied by atmospheric deposition and removed by scavenging onto particles. Fluvial and sedimentary inputs near the Rio de La Plata estuary and benthic sources from the Agulhas Bank resulted in elevated dTM concentrations in near-shore surface waters. These externally sourced dTMs were effectively delivered to the open ocean by offshore diffusion and/or advection, and potentially facilitated enhanced primary productivity along the transect.

中文翻译：

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对南大西洋 GEOTRACES GA10 断面铝、锰和钴分布的控制

微量金属 (TM) 锰 (Mn)、钴 (Co) 和铝 (Al) 在海洋中具有重要的地球化学和生物学作用。在这里，我们展示了 2010 年春季和 2011 年夏季运营的 GEOTRACES GA10 游轮沿南大西洋南纬 40° 的溶解 (d) 和颗粒铝、锰和钴的完整深度剖面。其特点是初级生产力增强，形成南大洋和南大西洋副热带环流之间的关键过渡带。 dAl、dCo 和 dMn 的平均浓度（±标准偏差）分别为 3.36 ± 2.65 nmol kg、35.3 ± 17.6 pmol kg 和 0.624 ± 1.08 nmol kg。它们在地表水中的分布是由外部来源和复杂的内部生物地球化学过程决定的。具体来说，海洋表层 dCo 是由浮游植物吸收、再矿化和外部输入之间的相互作用控制的； dMn 可能是通过 Mn 氧化物的形成和光还原来确定的； dAl通过大气沉积提供并通过清除到颗粒上而去除。拉普拉塔河口附近的河流和沉积物输入以及阿加勒斯浅滩的底栖来源导致近岸地表水中 dTM 浓度升高。这些外部来源的 dTM 通过近海扩散和/或平流有效地输送到公海，并可能促进沿横断面初级生产力的提高。