Copper (Cu) is a biologically important trace metal for marine plankton, but it is also toxic at high concentrations. Understanding the global distribution of Cu and the processes controlling its cycling in the ocean is important for understanding how the distribution of this important element can respond to climate change. Here, we use available observations of dissolved copper, an artificial neural network, and an ocean circulation inverse model, to derive a global estimate of the three‐dimensional distribution and cycling of dissolved Cu in the ocean. We find that there is net removal by bio‐assimilation and/or scavenging of dissolved Cu in the surface ocean at a rate of ~1.7 Gmol yr⁻¹ and that both the concentration and export of dissolved Cu are highest in the Southern Ocean. In the subsurface above the near‐sediment layer, dissolved Cu is removed at a net rate of ~2.4 Gmol yr⁻¹, consistent with scavenging onto sinking particles, contributing to an increase in the flux of particulate Cu with depth. This removal of Cu by scavenging in the interior ocean is balanced by a net near‐sediment source of dissolved Cu, which sustains a gradual increase in the concentration of dissolved Cu with depth. Globally, this net near‐sediment source is estimated at ~2.6 Gmol yr⁻¹ in the deep ocean and ~0.8 Gmol yr⁻¹ along continental shelves and slopes. Our results suggest an active oceanic dissolved Cu cycle with a mean internal ocean residence time of ~530 years, highlighting the potential for climate‐driven changes in the marine Cu cycle.

中文翻译：

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用数据同化诊断模型约束全球海洋铜循环

铜（Cu）是海洋浮游生物的重要生物微量金属，但在高浓度下也有毒。了解铜的全球分布以及控制铜在海洋中循环的过程对于了解这种重要元素的分布如何响应气候变化非常重要。在这里，我们使用溶解铜的可用观测值，人工神经网络和海洋环流逆模型，来得出海洋中溶解铜的三维分布和循环的全局估计。我们发现，通过生物同化和/或清除表层海洋中溶解的铜的净清除率约为1.7 Gmol yr ^-1并且溶解铜的浓度和出口在南大洋都最高。在近泥沙层上方的地下，溶解的铜以〜2.4 Gmol yr ^-1的净速率被去除，这与清除沉入的颗粒相一致，从而导致颗粒状Cu的流量随着深度的增加而增加。通过清除近海中的铜而去除的铜是由近乎纯净的可溶性铜沉积物平衡的，该来源可随着深度的增加而逐渐增加可溶性铜的浓度。在全球范围内，这种近沉积物的净量在深海中估计为〜2.6 Gmol yr ^-1，在〜0.8 Gmol yr ^-1沿大陆架和斜坡。我们的结果表明，一个活跃的海洋溶解铜循环，平均内部海洋停留时间约为530年，突显了由气候驱动的海洋铜循环变化的潜力。