报告人：John Reinfelder教授

报告时间：2015年06月09日上午，10:00-11:30

报告地点：B4-215

报告题目：Fractionation of mercury stable isotopes in aquatic environments

报告内容简介：

While mercury stable isotopes may potentially be used to track mercury in aquatic systems, much remains to be learned about how various abiotic and biological transformations of mercury affect their mass-dependent fractionation (MDF) and mass-independent fractionation (MIF).  We are currently examining MDF and MIF of mercury isotopes during the abiotic and biological photochemical reduction of inorganic mercury (Hg(II)) and methylmercury (MIF), and during the biological synthesis of methylmercury by iron- and sulfate-reducing bacteria.  Results from abiotic photochemical reactions confirm previous findings that UV light is required for MIF during reduction of Hg(II) and indicate that oxygen controls the sign of MIF for thiol-bound Hg(II).  The photochemical reduction of MeHg results in the enrichment of the reactant pool in 199Hg (positive MIF).  The photochemical reduction of intracellular mercury in a marine microalga results in negative MIF for Hg(II), but positive MIF for MeHg.  The implications of these results for tracking mercury in aquatic food webs will be discussed.