Constraining the Global Ocean Cu Cycle With a Data‐Assimilated Diagnostic Model
Constraining the Global Ocean Cu Cycle With a Data‐Assimilated Diagnostic Model
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DOI：
10.1029/2020gb006741
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发表时间：
2020-10
影响因子：
5.2
通讯作者：
S. Roshan;T. DeVries;Jingfeng Wu
中科院分区：
文献类型：
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作者：
S. Roshan;T. DeVries;Jingfeng Wu
铜（Cu）是海洋浮游生物重要的微量金属，但高浓度时也是有毒的。了解铜的全球分布和控制其在海洋中循环的过程对于了解这种重要元素的分布如何应对气候变化非常重要。在这里，我们使用现有的溶解铜观测结果，人工神经网络和海洋环流逆模型，以获得海洋中溶解铜的三维分布和循环的全球估计。我们发现，在海洋表层，通过生物同化和/或清除溶解的铜，以约1.7 Gmol/年的速率净去除，溶解的铜的浓度和出口在南大洋最高。在近沉积层上方的次表层中，溶解的Cu以约2.4 Gmol/年的净速率被去除，这与清除沉降颗粒一致，有助于颗粒Cu通量随深度增加。这种清除铜的内部海洋是平衡的溶解铜的净近沉积物来源，这维持溶解铜的浓度随着深度逐渐增加。在全球范围内，这种净近沉积物源在深海中估计约为2.6 Gmol yr−1，在沿着大陆架和斜坡约为0.8 Gmol yr−1。我们的研究结果表明，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，突出了海洋铜循环中气候驱动变化的潜力。
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.