University of Connecticut , Department of Marine Sciences, Groton, Connecticut 06340.
Environ Sci Technol. 2014 Jan 21;48(2):954-60. doi: 10.1021/es403030d. Epub 2014 Jan 7.
Mercury (Hg) speciation and the activity of Hg(II)-methylating bacteria are responsible for the rate of methylmercury production and thus bioaccumulation in marine foodwebs. Factors affecting porewater partitioning (Kd) and methylation of Hg(II) were examined at 11 sites in sediment of 4 biogeochemically diverse estuaries in the Northeast U.S. In Long Island Sound, 88% of total mercury (HgT) log Kd variability was described by porewater dissolved organic carbon concentration and sediment total sulfur (S) content. Whereas across all estuaries, regression analyses showed that S alone drives about 70% of Kd variability and 50% of changes in methylation rates; and the inclusion of DOC and sulfides did not improve the prediction. Thus, we demonstrated that S is a better predictor of HgT log Kd than the sediment organic matter across multiple estuaries, and while organic matter and S are interchangeable in small-scale studies, on a larger scale, sediment S content is the simplest and most effective variable to measure.
汞（Hg）的形态和具有将汞（Hg）甲基化能力的细菌的活性，决定了甲基汞的生成速度和海洋食物网中的汞生物累积率。本研究在 4 个美国东北部具有不同生物地球化学特征的河口的沉积物中选取了 11 个地点，考察了影响汞（Hg）在孔隙水中分配（Kd）和甲基化的因素。在长岛海峡，总汞（HgT）的 log Kd 变异性的 88%可由孔隙水中溶解态有机碳浓度和沉积物总硫（S）含量来描述。而在所有的河口，回归分析表明，S 单独解释了约 70%的 Kd 变异性和 50%的甲基化速率变化；而添加 DOC 和硫化物并不能提高预测效果。因此，我们的研究结果表明，在多个河口，S 是比沉积物有机质更好的 HgT log Kd 预测因子，虽然在小规模研究中有机质和 S 是可以互换的，但在更大的尺度上，沉积物 S 含量是最简单和最有效的可测量变量。
