Photomicrobial Visible Light-Induced Magnetic Mass Independent Fractionation of Mercury in a Marine Microalga
Photomicrobial Visible Light-Induced Magnetic Mass Independent Fractionation of Mercury in a Marine Microalga
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DOI：
10.1021/acsearthspacechem.7b00056
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发表时间：
2017-07
期刊：
影响因子：
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通讯作者：
K. Kritee;Laura C. Motta;J. Blum;M. Tsui;J. Reinfelder
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文献类型：
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作者：
K. Kritee;Laura C. Motta;J. Blum;M. Tsui;J. Reinfelder
甲基汞（MeHg）是一种高度神经毒性的物质，在水生食物网中积累，并富含奇数同位素（即，199 Hg和201 Hg），据称是地表沃茨非生物光降解的结果。本文通过以下几个方面的证据，强调了浮游植物在海洋食物网中甲基汞的非质量分馏（MIF）中的潜在作用：（1）海洋微藻球等鞭金藻（Isochrysis galbana）细胞内甲基汞的降解和细胞内无机汞（Hg（II））的还原;（2）一个大的，积极的MIF（Δ 199 Hg反应物- Δ 199 Hg产物）在无UVB的可见光照射下细胞内降解甲基汞过程中的变化规律为：Δ 199 Hg反应物- Δ 199 Hg产物= 0.5 -10‰，这与海洋食物网中富含奇数同位素的甲基汞的积累相一致;（3）在UVB光的存在下，细胞内Hg（II）还原过程中的负MIF（-1 ‰）。如果甲基汞在海洋浮游植物的光化学反应的代表，我们的研究结果表明，藻类细胞介导的甲基汞的可见光脱甲基化可以...
Methylmercury (MeHg), a highly neurotoxic substance, accumulates in aquatic food webs, and is enriched in odd isotopes (i.e., 199Hg and 201Hg), purportedly as a result of abiotic photodegradation in surface waters. Here, we highlight the potential role of phytoplankton in the mass independent fractionation (MIF) of MeHg in marine food-webs by providing evidence of (1) degradation of intracellular MeHg and reduction of intracellular inorganic mercury (Hg(II)) in the marine microalga, Isochrysis galbana; (2) a large, positive MIF (Δ199Hgreactant – Δ199Hgproduct ∼ 5–10‰) during intracellular degradation of MeHg in cells exposed to visible light with no UVB, consistent with the accumulation of odd isotope-enriched MeHg in marine food-webs; and (3) a negative MIF (−1‰) during intracellular reduction of Hg(II) in the presence of UVB light. If representative of the photochemical reactivity of MeHg in marine phytoplankton, our results indicate that algal cell-mediated demethylation of MeHg by visible light could ...