东海夏季溶解气态汞和活性汞分布特征及控制因素

于2018年6月在东海开展航次调查，测定了水体中溶解气态汞（dissolved gaseous mercury，DGM）、活性汞（reactive Hg，RHg）、总汞（total Hg，THg）及溶解态汞（dissolved Hg, DHg）浓度，探究了夏季东海水体中DGM和RHg的分布特征及其控制因素。结果表明,东海水体DGM和RHg浓度分别为（151.3±75.9 ）pg/L和（0.8±0.7） ng/L，DGM/THg、DGM/RHg和RHg/THg的数据分别为（4.5±2.5）%、（26.7±15.0）%和（21.6±14.8）%。与其他海洋体系相比，东海水体中DGM和RHg浓度显著高于多数大洋水体，低于或接近其他近海报道结果。空间分布上，东海水体DGM和RHg均呈现出相对复杂的分布趋势，在近岸浅层水、外海浅层及深层水中均存在明显的高值区，表明其可能受陆源输入和原位生成/去除过程共同控制。垂直分布上，底层水中DGM和RHg浓度相对较低，其他水层无显著差异。不同水层THg和DHg调查数据显示东海底层水中虽然THg浓度最高，但DHg相对其他水层浓度略低，这可能是导致底层水中RHg和DGM较低的主要原因。Spearman相关性分析和多元回归分析结果表明，RHg浓度和溶解氧（dissolved oxygen，DO）含量是影响海水中DGM浓度的关键控制因素，而DO含量是影响海水中RHg浓度的关键控制因素。

Distribution of dissolved gaseous mercury and reactive Hg and their controlling factors in the East China Sea in summer

Dissolved gaseous mercury (DGM), reactive Hg (RHg), total Hg (THg) and dissolved Hg (DHg) concentrations were analyzed in the seawater of the East China Sea (ECS) during a cruise in June 2018. The distribution patterns of DGM and RHg and their controlling factors in the East China Sea (ECS) were investigated. The concentrations of DGM and RHg in the seawater were determined to be (151.3±75.9) pg/L and (0.8±0.7) ng/L, respectively. The ratios of DGM/THg, DGM/RHg and RHg/THg were calculated to be (4.5±2.5)%, (26.7±15.0)% and(21.6±14.8)%, respectively. DGM and RHg concentrations in the ECS water were significantly higher than that in most open oceans, but lower than or comparable to that reported in most coastal seas. Both DGM and RHg in the seawater presented a complicated spatial distribution pattern, with high concentration areas located in both nearshore shallow seawater, and offshore shallow and deep seawater. These results indicate that both species of Hg may be controlled by both the terrestrial input and in situ production/removal processes. As for the vertical distribution, the concentrations of DGM and RHg in the bottom seawater were observed to be the lowest, while comparable concentrations were observed at all the other sampling layers. Although highest THg concentration was observed in the bottom seawater of the ECS, DHg concentrations in the bottom seawater were slightly lower than those at the other layers. This may be a reasonable explanation of the lower RHg and DGM concentrations in the bottom water. Spearman’s correlation and multiple regression analyses suggest that RHg and dissolved oxygen (DO) concentrations may be the major controlling factors for DGM in the seawater, while RHg in the seawater may be controlled by DO.