The Effect of Particle Composition and Concentration on the Partitioning Coefficient for Mercury in Three Ocean Basins
The Effect of Particle Composition and Concentration on the Partitioning Coefficient for Mercury in Three Ocean Basins
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DOI：
10.3389/fenvc.2021.660267
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发表时间：
2021-05-14
影响因子：
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通讯作者：
Lam, Phoebe J.
中科院分区：
文献类型：
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作者：
Cui, Xinyun;Lamborg, Carl H.;Lam, Phoebe J.
下沉颗粒的向下通量是海洋中重要的汞去除和重新分布过程；然而，它并没有得到很好的约束。我们利用来自太平洋、大西洋和北冰洋的三趟美国 GEOTRACES 航行的数据，检查了水柱中的汞分配系数 K-d。数据表明三个洋盆的 K-d 变化很大。我们还通过比较小尺寸（1-51μm）悬浮颗粒质量（SPM）的浓度及其在六个不同相中的成分分数与分配系数，研究了颗粒浓度和成分对 K-d 的影响。我们观察到 K-d 与悬浮颗粒质量之间存在反比关系，正如在其他金属中观察到的那样，称为“颗粒浓度效应”，这解释了 K-d 的大部分变化。颗粒有机物 (POM) 和碳酸钙 (CaCO3) 在所有三个海洋盆地中主导着汞的分配，而铁和锰在其浓度升高的某些地方可能会产生影响，例如在热液羽流中。最后，我们估计的汞停留时间与平均对数体积 K-d 具有很强的负相关性，表明 K-d 对汞停留时间有显着影响。
The downward flux of sinking particles is a prominent Hg removal and redistribution process in the ocean; however, it is not well-constrained. Using data from three U.S. GEOTRACES cruises including the Pacific, Atlantic, and Arctic Oceans, we examined the mercury partitioning coefficient, K-d, in the water column. The data suggest that the K-d varies widely over three ocean basins. We also investigated the effect of particle concentration and composition on K-d by comparing the concentration of small-sized (1-51 mu m) suspended particulate mass (SPM) as well as its compositional fractions in six different phases to the partitioning coefficient. We observed an inverse relationship between K-d and suspended particulate mass, as has been observed for other metals and known as the "particle concentration effect," that explains much of the variation in K-d. Particulate organic matter (POM) and calcium carbonate (CaCO3) dominated the Hg partitioning in all three ocean basins while Fe and Mn could make a difference in some places where their concentrations are elevated, such as in hydrothermal plumes. Finally, our estimated Hg residence time has a strong negative correlation with average log bulk K-d, indicating that K-d has significant effect on Hg residence time.