From 28 March to 17 April, 2018, different forms of mercury (Hg) in the Yellow Sea and Bohai Sea were measured to study the influencing factors on the distribution and transformation of Hg in spring using a shared cruise. The mean concentration of dissolved gaseous mercury (DGM) in the surface water of the Yellow and Bohai Seas was (44.3 ± 43.9) pg/L, which was close to that in mid-latitude oceans and deep seas. The ratio of DGM to THg (total mercury) was lower than in the oceans and in the Yellow and Bohai Seas in summer or fall. DGM concentrations in surface water were highest in the central part of the South Yellow Sea and were higher than those in the Bohai Sea, and their spatial distributions were consistent with RHg (reactive mercury). DGM and RHg correlated positively with water temperature in surface seawater ( r = 0.506, P < 0.01; r = 0.278, P < 0.05). The concentrations of both DGM and RHg in surface water were controlled by solar radiation and water temperature. Foggy weather did not benefit the production of DGM and RHg. DGM in the bottom seawater was mainly affected by Dissolved Oxygen and water temperature ( r = −0.366, P < 0.01; r = 0.331, P < 0.01), produced mainly by anaerobic reactions of the bottom seawater and sediment microorganisms. The bottom DGM concentrations in the Yellow and Bohai Seas were the highest, and DGM produced in bottom seawater and sediment plays a more important role than the surface water in spring. The concentrations of DGM and RHg in the surface and bottom water in the South Yellow Sea were all higher than those in the middle layer. Vertical variations in the North Yellow Sea and the Bohai Sea were small. The production and distribution of DGM and RHg were influenced by differences of latitude and by the Yellow Sea warm current in spring.

中文翻译：

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春季黄渤海溶解气态汞的空间差异及影响因素

2018年3月28日至4月17日，利用共享游轮对黄渤海不同形态的汞（Hg）进行了测量，研究了春季Hg分布和转化的影响因素。黄渤海表层水中溶解气态汞（DGM）平均浓度为（44.3±43.9）pg/L，与中纬度海洋和深海接近。夏季或秋季 DGM 与 THg（总汞）的比率低于海洋以及黄海和渤海。地表水中DGM浓度以南黄海中部最高，高于渤海，空间分布与RHg（活性汞）一致。DGM和RHg与表层海水水温呈正相关（r=0.506，P<0.01；r = 0.278，P < 0.05）。地表水中 DGM 和 RHg 的浓度受太阳辐射和水温的控制。大雾天气不利于 DGM 和 RHg 的生产。底层海水中的DGM主要受溶解氧和水温的影响（r=-0.366，P<0.01；r=0.331，P<0.01），主要由底层海水和沉积物微生物的厌氧反应产生。黄海和渤海海底DGM浓度最高，春季底层海水和沉积物中产生的DGM比地表水的作用更大。南黄海表层和底层水中DGM和RHg的浓度均高于中层。北黄海和渤海的垂直变化较小。