Effects of sulfate-reducing bacteria on methylmercury at the sediment-water interface.
Effects of sulfate-reducing bacteria on methylmercury at the sediment-water interface.
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DOI：
10.1016/j.jes.2016.05.018
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发表时间：
2016-08
影响因子：
6.9
通讯作者：
Lingxia Zeng;Guangjun Luo;Tianrong He;Yanna Guo;Xiaoli Qian
中科院分区：
文献类型：
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作者：
Lingxia Zeng;Guangjun Luo;Tianrong He;Yanna Guo;Xiaoli Qian
为了解硫酸盐还原菌（SRB）对沉积物-水界面汞（Hg）甲基化的影响，以百花水库沉积物柱样（含沉积物和上覆水）为材料，在不同氧化还原条件和微生物活性条件下进行培养。在厌氧阶段和好氧阶段分别测定了生物活性保持（BAC）、硫酸盐还原菌抑制（SRBI）和细菌完全抑制（BACI）的对照岩心上覆水中溶解性甲基汞（DMeHg）的浓度。对于BAC和SRBI柱样，沃茨中DMeHg浓度在厌氧阶段远高于好氧阶段，且与溶解氧浓度呈负相关（BAC和SRBI柱样分别为r=-0.5311和r =-0.4977）。SRBI柱样的DMeHg浓度比BAC柱样低50%，表明SRB在沉积物-水系统中的汞甲基化中起重要作用，但除SRB外，还可能有铁还原菌和含特定基因簇（hgcAB）的微生物引起沉积物-水系统中的汞甲基化。
Sediment cores (containing sediment and overlying water) from Baihua Reservoir (SW China) were cultured under different redox conditions with different microbial activities, to understand the effects of sulfate-reducing bacteria (SRB) on mercury (Hg) methylation at sediment–water interfaces. Concentrations of dissolved methyl mercury (DMeHg) in the overlying water of the control cores with bioactivity maintained (BAC) and cores with only sulfate-reducing bacteria inhibited (SRBI) and bacteria fully inhibited (BACI) were measured at the anaerobic stage followed by the aerobic stage. For the BAC and SRBI cores, DMeHg concentrations in waters were much higher at the anaerobic stage than those at the aerobic stage, and they were negatively correlated to the dissolved oxygen concentrations (r= − 0.5311 andr= − 0.4977 for BAC and SRBI, respectively). The water DMeHg concentrations of the SRBI cores were 50% lower than those of the BAC cores, indicating that the SRB is of great importance in Hg methylation in sediment–water systems, but there should be other microbes such as iron-reducing bacteria and those containing specific gene cluster (hgcAB), besides SRB, causing Hg methylation in the sediment–water system.