Collaborative Research: Mercury Biogeochemistry in a Semi-Arid Aquatic Ecosystem: Processes Controlling Methylation and Demethylation

合作研究：半干旱水生生态系统中的汞生物地球化学：控制甲基化和去甲基化的过程

• 批准号: 9523894
• 负责人: Mark Hines
• 金额: $ 22.1万
• 依托单位: University of New Hampshire
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-15 至 1998-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9523894&HistoricalAwards=false
• 关键词: Collaborative; Research; Mercury; Biogeochemistry; Semi

9523894 Hines The biogeochemistry of mercury is important because of the toxicity of methylmercury, its accumulation in biota, and its biomagnification in food chains. A knowledge of the concentration, transport, and dynamics of methylmercury is needed to predict its potential impact on human and aquatic life. The proposed program combines biogeochemical, microbiological, and molecular investigations of the formation and degradation of methylmercury with certain abiotic factors, and a robust modeling effort, to depict factors controlling methylmercury dynamics in the Carson River/Lahontan Reservoir System in Nevada. The Carson System received 7000 tons of elemental mercury during the 19th century for gold amalgamation, and now provides a strong gradient in mercury concentrations. Specific goals are to: 1) locate sources and sinks of methylmercury; 2) examine bacterial processes including genetic controls and the role of terminal decomposition; 3) investigate the relationship between the sulfur and mercury cycles, and 4) develop simulation models. The project will consist of two major overlapping activities. First, surveys of : 1) rates of mercury transformation; 2) expression of bacterial genes incurring mercury resistance; 3) rates of model will be developed and validated, and used to fine tune future sampling programs. Second, the program will address hypotheses encompassing: 1) interactions among mercury concentration and speciation; 2) the role of bacteria as producers and consumers of methylmercury; 3) changes in genetics and methylmercury concentrations; 4) the role of suspended particles, and; 5) fluxes of methylmercury from sediments. The simulation model will be refined using biogeochemical data and used for predictive purposes. The project will provide data essential for determining controls on the accumulation of methylmercury in fish and other higher forms of life in semi-arid ecosystems, and will be useful for comparison to wet and northern environments. In general, the research will distinguish aspects of aquatic systems that most influence the production, degradation, and transport of methylmercury, one of the Earth's most insidious pollutants.

9523894 Hines由于甲基汞的毒性、其在生物群中的积累以及其在食物链中的生物放大作用，汞的地球化学非常重要。 要预测甲基汞对人类和水生生物的潜在影响，需要了解甲基汞的浓度、迁移和动力学。 拟议的方案结合了地球化学，微生物和分子的甲基汞的形成和降解的调查与某些非生物因素，和一个强大的建模工作，描绘因素控制甲基汞在卡森河/拉洪坦水库系统在内华达州的动态。 卡森系统在19世纪世纪期间接收了7000吨元素汞用于金汞齐化，现在提供了汞浓度的强烈梯度。 具体目标是：1）确定甲基汞的来源和汇; 2）研究细菌过程，包括遗传控制和终端分解的作用; 3）调查硫和汞循环之间的关系; 4）开发模拟模型。 该项目将包括两项主要的重叠活动。 第一，调查：1）汞转化率; 2）引起耐汞性的细菌基因的表达; 3）将开发和验证模型的速率，并用于微调未来的采样程序。 其次，该计划将解决假设，包括：1）汞浓度和物种形成之间的相互作用; 2）细菌作为甲基汞生产者和消费者的作用; 3）遗传和甲基汞浓度的变化; 4）悬浮颗粒的作用; 5）沉积物中甲基汞的通量。 模拟模型将使用地球化学数据进行改进，并用于预测目的。 该项目将为确定控制甲基汞在半干旱生态系统中鱼类和其他高级生命形式中的积累提供必要的数据，并将有助于与潮湿和北方环境进行比较。 总的来说，这项研究将区分水生系统的各个方面，这些方面对甲基汞（地球上最阴险的污染物之一）的生产、降解和运输影响最大。