Microbial generation of elemental mercury from dissolved methylmercury in seawater.
Microbial generation of elemental mercury from dissolved methylmercury in seawater.
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微生物从海水中溶解的甲基汞产生元素汞。
DOI：
10.1002/lno.11068
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发表时间：
2019
影响因子：
4.5
通讯作者：
Fisher,NicholasS
中科院分区：
文献类型：
--
作者：
Lee,Cheng-Shiuan;Fisher,NicholasS
光还原和微生物活动导致海水中其他汞物质形成元素汞 (Hg 0)，从而可能从海水逃逸到上层空气中。海水中一甲基汞 (MeHg) 向 Hg 0 的微生物转化仍未量化。使用发射 203 Hg 的 203 Hg 作为示踪剂开发了一种快速放射测定方法，以评估低 pM 范围内 Hg (II) 和 MeHg 产生的 Hg 0 。研究发现，大西洋表层海水和长岛海湾水中的浮游细菌组合能够快速产生 Hg0，其生产速率常数与细菌生物量直接相关，且与溶解的 Hg (II) 和 MeHg 浓度无关。在细菌生物量较低的大西洋表层海水中，约 32% Hg (II) 和 19% MeHg 在 4 d 内转化为 Hg 0 ，而在细菌生物量较高的长岛海湾水域，54% Hg (II) 和 8% MeHg 转化为 Hg 0 。温度从 24°C 降低到 4°C ，使 Hg (II) 的 Hg 0 生成率 cell− 1 降低了 3.3 倍。就像来自甲基汞源一样。由于 Hg 0 生成速率与微生物生物量和温度呈线性相关，并且在我们的现场样品中检测到了微生物汞还原酶，因此我们推断微生物代谢活动和酶反应主要控制光穿透减弱的地下水中 Hg 0 的形成。
Elemental mercury (Hg 0) formation from other mercury species in seawater results from photoreduction and microbial activity, leading to possible evasion from seawater to overlying air. Microbial conversion of monomethylmercury (MeHg) to Hg 0 in seawater remains unquantified. A rapid radioassay method was developed using gamma-emitting 203 Hg as a tracer to evaluate Hg 0 production from Hg (II) and MeHg in the low pM range. Bacterioplankton assemblages in Atlantic surface seawater and Long Island Sound water were found to rapidly produce Hg0, with production rate constants being directly related to bacterial biomass and independent of dissolved Hg (II) and MeHg concentrations. About 32% of Hg (II) and 19% of MeHg were converted to Hg 0 in 4 d in Atlantic surface seawater containing low-bacterial biomass, and in Long Island Sound water with higher bacterial biomass, 54% of Hg (II) and 8% of MeHg were transformed to Hg 0. Decreasing temperatures from 24C to 4C reduced Hg 0 production rates cell− 1 from Hg (II) 3.3 times as much as from a MeHg source. Because Hg 0 production rates were linearly related to microbial biomass and temperature, and microbial mercuric reductase was detected in our field samples, we inferred that microbial metabolic activities and enzymatic reactions primarily govern Hg 0 formation in subsurface waters where light penetration is diminished.