PECASE: Mercury Methylation in Sulfate-Reducing Biofilms

食物链的汞(Hg)污染是一个世界性的问题，即使在原始地区也构成了公共卫生威胁。在水生系统中，汞的甲基化是一个关键的过程，在这个过程中，毒性较小的无机汞被微生物转化为甲基汞，甲基汞是一种强烈的神经毒素，在食物链中有放大的趋势。虽然汞甲基化过程对于了解我们是否要预测或减轻汞污染的影响至关重要，但控制其速度的因素是极其复杂的。硫酸盐还原细菌(SRB)已被证明是广泛的水生系统中的主要汞甲基化因子，汞对细菌的生物有效性以及特定种类硫酸盐还原细菌的活性都被证明是控制汞甲基化速度的重要因素。智力价值：这项工作解决了与控制汞甲基化的环境因素有关的基本问题。这项工作将阐明汞的形态对还原环境中甲基化的影响，硫酸盐还原细菌菌株的重要性，以及生物膜形成对硫酸盐还原生物膜中甲基化的影响。服务学习方面的教育创新成果也将通过文献和网上可访问的文件向公众公布。更广泛的影响：拟议工作的结果对于准确模拟汞在环境中的命运是必要的。所获得的信息可以扩展到对生物膜系统中其他污染物的研究，无论是天然的还是工程的。这项工作也可能直接适用于湿地恢复和湖泊管理决策。PI目前正与加州大学洛杉矶分校体验教育和服务学习中心(CEESL)合作开发一门创新的服务学习课程，在该课程中，加州大学洛杉矶分校的学生将学习湿地功能，然后在洛杉矶的经济困难学生的六年级教室中教授湿地功能。将开发的教学单元将包括四个课堂实验课程，最终将是六年级学生(由加州大学洛杉矶分校的学生陪同)到巴洛纳湿地的实地考察。每年夏天，国际湿地协会都会为支持湿地科学课程的教师提供培训。

0348783JayMercury (Hg) contamination of food chains is a worldwide problem, posing public health threats even in pristine areas. In aquatic systems, mercury methylation is a key process, whereby less-toxic inorganic mercury is microbially transformed to methylmercury, which is a potent neurotoxin with a strong tendency to magnify in concentration in food chains. While the process of mercury methylation is critical to understand if we are to predict or mitigate impacts due to mercury contamination, the factors controlling its rate are extremely complex. Sulfate-reducing bacteria (SRB) have been shown to be the primary mercury methylators in a wide range of aquatic systems, and bioavailability of mercury to the bacteria, as well as the activity of particular species of sulfate-reducing bacteria present, have both been shown to be important factors in controlling the rate of mercury methylation. Intellectual merit: This work addresses fundamental questions regarding the environmental factors controlling mercury methylation. This work will elucidate the effects of mercury speciation on methylation in reducing environments, the importance of the strain of sulfate-reducing bacteria, and the effects of biofilm formation on methylation in sulfate-reducing biofilms. Results from the educational innovations in service-learning will also be made available to the public via the literature and web-accessible documents. Broader impacts: Results from the proposed work are necessary for accurately modeling of the fate of mercury in the environment. Information gained can be extended to the study of other contaminants in biofilm systems, both natural and engineered. This work may also be directly applicable to wetland restoration and lake management decisions. The PI is currently working with the UCLA Center for Experiential Education and Service Learning (CEESL) to develop an innovative service-learning course in which UCLA students will learn and then teach wetland functions in grade 6 classrooms to economically disadvantaged students of Los Angeles. The teaching unit to be developed will involve four in-class laboratory sessions and will culminate in a field trip for the grade 6 students (accompanied by the UCLA students) to Ballona Wetland. A teacher training to support the wetland science curriculum will be given by the PI each summer.