The largest bioconcentration step of most metals, including methylmercury (MeHg), in aquatic biota is from water to phytoplankton, but the extent to which dissolved organic matter (DOM) affects this process for MeHg largely remains unexplored in marine systems. This study investigated the influence of specific sulfur-containing organic compounds and naturally occurring DOM on the accumulation of MeHg in a marine diatom Thalassiosira pseudonana. Initial uptake rate constants and volume concentration factors (VCFs) of MeHg were calculated to evaluate MeHg enrichment in algal cells in the presence of a range of organic compound concentrations. At environmentally realistic and higher concentrations, the addition of glycine and methionine had no effect on algal MeHg uptake, but thiol-containing compounds such as cysteine and thioglycolic acid reduced MeHg accumulation in algal cells at high added concentrations (> 100 times higher than naturally occurring concentrations). However, environmentally realistic concentrations of glutathione, another thiol-containing compound as low as 10 nM, resulted in a decline of ~ 30% in VCFs, suggesting its possible importance in natural waters. Humic acid additions of 0.1 and 0.5 mg C/L also reduced MeHg VCFs by ~ 15% and ~ 25%, respectively. The bioaccumulation of MeHg for T. pseudonana in coastal waters with varying levels of dissolved organic carbon (DOC) was inversely correlated with bulk DOC concentrations. Generally, naturally occurring DOM, particularly certain thiol-containing compounds, can reduce MeHg uptake by phytoplankton.

在水生生物群中，包括甲基汞（MeHg）在内的大多数金属中最大的生物富集步骤是从水到浮游植物，但是在海洋系统中，对于有机汞的溶解有机物（DOM）的影响程度在很大程度上尚待探索。这项研究调查了特定的含硫有机化合物和天然存在的DOM对海洋硅藻Thalassiosira pseudonana中MeHg积累的影响。计算MeHg的初始摄取速率常数和体积浓缩因子（VCF），以评估在一定范围的有机化合物浓度下藻类细胞中MeHg的富集情况。在环境上可行且浓度较高的情况下，添加甘氨酸和蛋氨酸对藻类的MeHg吸收没有影响，但是在高添加浓度下，含巯基的化合物（如半胱氨酸和巯基乙酸）减少了藻类细胞中MeHg的积累（比天然存在的含量高100倍以上）浓度）。然而，谷胱甘肽的环境现实浓度（另一种低至10 nM的含硫醇化合物）导致VCF下降约30％，表明其在天然水中的重要性。添加0.1和0.5 mg C / L的腐殖酸也分别使MeHg VCF降低了约15％和约25％。沿海水域中溶解有机碳（DOC）含量不同的拟南芥T.与散装DOC浓度成反比。通常，天然存在的DOM，尤其是某些含硫醇的化合物，可以减少浮游植物对MeHg的吸收。