Moss Landing Marine Laboratories, 8272 Moss Landing Road, Moss Landing, CA 95039, USA; University of California Santa Cruz, Ocean Sciences Department, 1156 High Street, Santa Cruz, CA 95064, USA.
University of California Santa Cruz, Ocean Sciences Department, 1156 High Street, Santa Cruz, CA 95064, USA.
Sci Total Environ. 2020 Mar 25;710:136166. doi: 10.1016/j.scitotenv.2019.136166. Epub 2019 Dec 18.
Mercury (Hg) is a ubiquitous metal in the ocean that undergoes in situ chemical transformations in seawater and marine sediment. Most relevant to public health is the production of monomethyl-Hg, a neurotoxin to humans that accumulates in marine fish and mammals. Here we synthesize 30 years of Hg measurements in the ocean to discuss sources, sinks, and internal cycling of this toxic metal. Global-scale oceanographic survey programs (i.e. CLIVAR and GEOTRACES), refined protocols for clean sampling, and analytical advancements have produced over 200 high-resolution, full-depth profiles of total Hg, methylated Hg, and gaseous elemental Hg throughout the Atlantic, Pacific, Arctic, and Southern Oceans. Vertical maxima of methylated Hg were found in surface waters, near the subsurface chlorophyll maximum, and in low-oxygen thermocline waters. The greatest concentration of Hg in deep water was measured in Antarctic Bottom Water, and in newly formed Labrador Sea Water, Hg showed a decreasing trend over the past 20 years. Distribution of Hg in polar oceans was unique relative to lower latitudes with higher concentrations of total Hg near the surface and vertical trends of Hg speciation driven by water column stratification and seasonal ice cover. Global models of Hg in the ocean require a better understanding of biogeochemical controls on Hg speciation and improved accuracy of methylated Hg measurements within the international community.
汞（Hg）是海洋中普遍存在的金属，在海水中和海洋沉积物中会发生原位化学转化。与公众健康最相关的是一甲基汞的生成，一甲基汞是一种对人类具有神经毒性的物质，会在海洋鱼类和哺乳动物中积累。在这里，我们综合了 30 年来海洋中汞的测量结果，讨论了这种有毒金属的来源、汇和内部循环。全球性的海洋学调查项目（如 CLIVAR 和 GEOTRACES）、改进的清洁采样方案以及分析技术的进步，已经在大西洋、太平洋、北极和南大洋产生了 200 多个总汞、甲基汞和气态元素汞的高分辨率、全深度剖面。甲基汞的垂直最大值出现在表层水中、次表层叶绿素最大值附近以及低氧温跃层水中。在南极底层水和新形成的拉布拉多海水中，深水中的汞浓度最高，在过去的 20 年中，汞在拉布拉多海水中的浓度呈下降趋势。极地海洋中汞的分布与低纬度地区不同，表层附近总汞浓度较高，汞的形态分布趋势受水柱分层和季节性冰盖的影响。海洋汞的全球模型需要更好地了解汞形态的生物地球化学控制，并提高国际社会对甲基汞测量的准确性。
