Project 7: Bioaccumulation and Trophic Transfer of Mercury in Aquatic Food Webs

汞是一种强烈的神经毒素，具有重大的生态和公共卫生问题。作为野生动物和人类 暴露主要通过鱼类发生，44个州发布了关于汞的鱼类消费建议 污染包括21个全州范围的淡水和12个沿海水域的建议。90%以上的 人类食用的鱼类和贝类来自海洋系统，但对海洋中汞命运的研究 生态系统仍然有限。人类和野生动物也通过鱼类增加了汞的暴露 被认为是“汞热点”的水库。项目7研究了驱动站点间差异的机制 水生食物网中汞的生物有效性、生物积累和营养转移 从森林到工业化的流域。在实地和实验研究中，我们将进行平行调查。 影响水库和河口无机汞和甲基汞归宿的过程，重点是低营养化 汞进入食物链的水平。我们预测，汞的生物有效性和汞在不同地点的差异 生物积累将基于环境属性，如物理(表面积、流域面积)、 化学因素(pH、养分、有机碳)、生态因素(底栖和远洋摄食)和土地利用因素 (农业、林业、工业)。我们将使用实地调查和实验方法来确定 汞对中上层和底栖食物网生物有效性的控制机制及其相对评价 作为汞营养转移管道的重要性。这项提议有三个具体目标。目标1的特点是 汞在田间的生物有效性、生物积累和营养转移，并测试生物积累是否 汞在受污染的场地中的转移得到加强，同时通过增加 环境中的有机物质。目的2调查底栖生物与远洋生物的强度和一致性。 作为汞向鱼类输送的食物网，以及鱼类体内有机质的数量和质量 沉积物和水减少了汞的吸收和转移。目标3调查特定机制的作用 例如，控制个体生物对汞的生物积累的体细胞生长稀释。结果来自 所有这三个目标都将被合成一个数学污染命运模型，该模型将评估净影响 影响汞生物有效性、生物累积量和汞的多种生态和生物地球化学因素 营养转移。

Mercury is a potent neurotoxin of significant ecological and public health concern. As wildlife and human exposure occurs largely through fish, 44 states have issued fish consumption advisories regarding Hg contamination including 21 statewide advisories for freshwater and 12 for coastal waters. More than 90% of fish and shellfish consumed by humans come from marine systems but research on Hg fate in marine ecosystems remains limited. Humans and wildlife also have elevated exposures to Hg via fish from reservoirs that are considered "Hg hotspots". Project 7 studies mechanisms driving site-to site variation in bioavailability, bioaccumulation, and trophic transfer of Hg in aquatic food webs across a gradient from forested to industrialized watersheds. In both field and experimental studies we will investigate parallel processes influencing inorganic and MeHg fate in reservoirs and estuaries with a focus on lower trophic levels where Hg enters the food web. We predict that site-to-site variation in Hg bioavailability and bioaccumulation will be based on environmental properties such as physical (surface area, watershed area), chemical (pH, nutrients, organic carbon), ecological (benthic and pelagic feeding), and land use factors (agricultural, forested, industrial). We will use field survey and experimental approaches to identify the mechanisms controlling Hg bioavailability to pelagic and benthic food webs and evaluate their relative importance as conduits of Hg trophic transfer. This proposal has three specific aims. Aim 1 characterizes Hg bioavailability, bioaccumulation, and trophic transfer in the field and tests whether the bioaccumulation and transfer of Hg is enhanced in contaminated sites while at the same time diminished by increasing organic matter in the environment. Aim 2 investigates the strength and consistency of benthic vs. pelagic food webs as conduits of Hg to fish and the degree to which the quantity and quality of organic matter in sediments and water diminish Hg uptake and transfer. Aim 3 investigates the role of specific mechanisms such as somatic growth dilution in controlling bioaccumulation of Hg by individual organisms. Results from all three aims will be synthesized into a mathematical contaminant fate model that will assess the net effect of the multiple ecological and biogeochemical factors influencing Hg bioavailability, bioaccumulation, and trophic transfer.