The Importance of Reversible Scavenging for the Marine Zn Cycle Evidenced by the Distribution of Zinc and Its Isotopes in the Pacific Ocean
The Importance of Reversible Scavenging for the Marine Zn Cycle Evidenced by the Distribution of Zinc and Its Isotopes in the Pacific Ocean
复制标题
太平洋锌及其同位素的分布证明了可逆清除对海洋锌循环的重要性
DOI：
10.1029/2022jc019419
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Conway, T. M.
中科院分区：
文献类型：
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作者：
Sieber, M.;Lanning, N. T.;Bian, X.;Yang, S. ‐C.;Takano, S.;Sohrin, Y.;Weber, T. S.;Fitzsimmons, J. N.;John, S. G.;Conway, T. M.
北太平洋在海洋溶解锌和硅之间的全球相关性的起源正在进行的讨论中发挥了重要作用，而在北太平洋的数据仍然稀少。在这里，我们提出了溶解锌和δ 66锌数据从美国GEOTRACES GP15纬向样带沿着152°W从阿拉斯加到南太平洋。在南部（<20°N），Zn和Si呈现出紧密的线性相关性，反映了强烈的南大洋影响，而在北部（>20°N），上层和中层沃茨中Zn相对于Si的过量是由于Zn和PO4的再生。使用一个机械模型，我们表明，可逆清除是需要作为一个额外的过程中转移锌从上层到深海，解释深锌最大值低于PO4最大值。应用于可逆清除的这种机制也为观察到的同位素分布提供了解释：（a）配体结合期间的分馏和随后在上层海洋中残留的重Zn的去除，驱使上层海洋朝向较低的δ 66 Zn，而（B）重Zn的释放与载体颗粒再生的PO 4最大值相一致，导致中等深度的δ 66 Zn最大值。在海洋上层，季节性物理层结是影响浅层δ 66 Zn信号的另一个重要过程。在全球范围内，这种机制在配体结合过程中引发分馏，再加上可逆的清除，为浅深度的同位素轻锌和相应的升高的中深度δ 66 Zn信号提供了一个全球性的解释，主要见于远离南大洋强控制的海洋区域。
The North Pacific has played an important role in ongoing discussions on the origin of the global correlation between oceanic dissolved Zn and Si, while data in the North Pacific have remained sparse. Here, we present dissolved Zn and δ66Zn data from the US GEOTRACES GP15 meridional transect along 152°W from Alaska to the South Pacific. In the south (<20°N) Zn and Si exhibit a tight linear correlation reflecting strong Southern Ocean influence, while in the north (>20°N) an excess of Zn relative to Si in upper and intermediate waters is due to regeneration of Zn together with PO4. Using a mechanistic model, we show that reversible scavenging is required as an additional process transferring Zn from the upper to the deep ocean, explaining the deep Zn maximum below the PO4maximum. This mechanism applied for reversible scavenging also provides an explanation for the observed isotope distribution: (a) fractionation during ligand binding and subsequent removal of residual heavy Zn in the upper ocean, drives the upper ocean toward lower δ66Zn, while (b) release of heavy Zn then coincides with the PO4maximum where carrier particles regenerate, causing a mid‐depth δ66Zn maximum. In the upper ocean, seasonal physical stratification is an additional important process influencing shallow δ66Zn signals. At the global scale, this mechanism invoking fractionation during ligand binding coupled with reversible scavenging offers a global explanation for isotopically light Zn at shallow depths and corresponding elevated mid‐depth δ66Zn signals, seen dominantly in ocean regions away from strong Southern Ocean control.