Methylmercury Production and Fate in Response to Multiple Environmental Factors

项目2：摘要 食用受汞污染的鱼类是美国和全球严重的公共卫生问题。 海洋鱼类是人类接触甲基汞（MeHg）的最重要媒介， 汞的形式。接触甲基汞对孕妇和儿童尤其令人关切， 神经、发育、心血管和免疫影响。项目2的总体目标是 确定多种环境因素的变化将如何改变 河口食物网是人类接触的重要途径。我们将研究互动 温度、盐度和碳含量变化对产量的影响（加性和非加性） 以及甲基汞在沿海海洋系统中的归宿，以便预测区域变化的净影响 气候变化对人类接触甲基汞的影响。该项目将利用实地研究和实验室 测量一系列环境相关温度、盐度和碳的影响的实验 微生物活动负荷、汞甲基化和甲基汞去甲基化速率、沉积物甲基汞含量和汞 从沉积物到上覆水的甲基汞通量。将进行实验室和围隔实验， 研究温度、盐度和有机碳对海洋生物多样性的单独和综合影响。 甲基汞在浮游植物中的生物浓缩，以及向浮游动物和鱼类的营养转移， 人类食用的高营养级鱼类。实地工作和中型生态系统实验将在 位于不同纬度的河口，沉积物中的碳浓度有高有低，以便 比较不同地球化学和温度制度下的甲基汞过程。获得的数据 实验室和现场实验将用于参数化和联系当前的命运，运输， 生物累积模型与人体接触模型。这些综合方法将改善我们的 了解复杂的环境变化对海洋环境中甲基汞归宿和生物累积的影响 生态系统，以及这些因素对人类接触甲基汞的影响。

Project 2: Abstract Consumption of fish contaminated with mercury is a serious public health concern in the US and globally. Marine fish are the most important agents of exposure for humans to methylmercury (MeHg), the most toxic form of mercury. MeHg exposure is of particular concern for pregnant women and children and has known neurological, developmental, cardiovascular, and immunological effects. The overall goal of Project 2 is to determine how changes in multiple environmental factors will alter the production and fate of MeHg in estuarine food webs, which are important pathways of exposure to humans. We will investigate the interactive effects (additive and non-additive) of changes in temperature, salinity, and carbon content on the production and fate of MeHg in coastal marine systems in order to predict the net influence of regional variability as well as climate change on human exposure to MeHg. The project will utilize field studies and laboratory experiments to measure the effect of a range of environmentally relevant temperatures, salinities, and carbon loads on microbial activity, Hg methylation and MeHg demethylation rates, sediment MeHg content and Hg and MeHg flux from sediments to overlying water. Laboratory and mesocosm experiments will be conducted to examine the individual and combined effects of temperature, salinity and organic carbon on the bioconcentration of MeHg into phytoplankton, and trophic transfer to zooplankton and fish that are prey for higher trophic level fish consumed by humans. Field work and mesocosms experiments will be undertaken in estuaries located at different latitudes with high and low carbon concentrations in sediments in order to compare MeHg processes under different biogeochemical and temperature regimes. Data obtained from laboratory and field experiments will be used to parameterize and link current fate, transport, and bioaccumulation models with human exposure models. These combined approaches will improve our understanding of the impact of complex environmental alterations on MeHg fate and bioaccumulation in marine ecosystems, and the impact of these factors on MeHg exposure to humans.