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 汞的接触主要是通过鱼类进行的，44个州已经发布了有关汞的鱼类消费禁令 污染，包括21个州的淡水和12个沿海沃茨。90%以上 人类食用的鱼类和贝类来自海洋系统，但海洋中汞的归宿研究 生态系统仍然有限。人类和野生动物通过鱼类接触汞的程度也有所增加， 被认为是“汞热点”的水库。项目7研究驱动站点间差异的机制， 汞在水生食物网中的生物利用度、生物累积性和营养转移， 从森林到工业化流域在现场和实验研究中，我们将研究平行 影响水库和河口无机物和甲基汞归宿的过程，重点关注低营养 汞进入食物网的水平。我们预测汞生物利用度的站点间变化， 生物蓄积性将基于环境特性，如物理特性（表面积、流域面积）， 化学因素（pH值、营养物、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）。我们将采用实地调查和实验的方法来确定 控制汞对浮游和底栖食物网生物利用率的机制，并评估其相对生物利用率。 作为汞营养转移渠道的重要性。这项建议有三个具体目标。目标1描述了 汞的生物有效性、生物累积性和营养转移，并测试生物累积性是否 汞的迁移在污染场地得到加强，同时， 环境中的有机物。目标2调查底栖与中上层的强度和一致性 食物网作为汞向鱼类输送的渠道，以及食物网中有机物的数量和质量 沉积物和水减少了汞的吸收和转移。目标3研究特定机制的作用 例如控制个别生物体对汞的生物积累的体细胞生长稀释。结果 所有这三个目标将综合成一个数学污染物归宿模型，以评估净效应 影响汞生物利用度、生物累积性和生物安全性的多种生态和地球化学因素， 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.