Ecological processes controlling methylmercury production in prairie wetlands

无机汞（HgII）的微生物甲基化是环境汞循环中最重要的转化，因为其产物是汞的神经毒性甲基化形式（甲基汞; MeHg），很容易被人类和野生动物生物积累。 甲基汞的产生被认为主要是由微生物介导的，水生环境中汞甲基化的数量取决于控制微生物种群增长或代谢功能的环境因素。 促进汞甲基化的因素在湿地沉积物中尤为重要，北美大平原的草原湿地为高汞甲基化率提供了理想的条件。 草原湿地是重要的野生动物栖息地，为数百种野生动物和非野生动物物种提供了掩护和筑巢场所，并包含了北美最重要的水禽繁殖栖息地。 甲基汞生产率的提高可能会对草原野生动物造成重大的健康和环境风险。 同样，如果水禽的甲基汞浓度很高，猎人及其家人食用草原野生动物时接触的甲基汞浓度可能会超过汞消费指南。 目前还没有关于草原湿地中甲基汞的信息，这一主题提出了两个重要问题：1。不同类型草原湿地的水、沉积物和生物群中甲基汞的浓度是多少？和2.控制草原湿地甲基汞生成的化学和物理机制是什么？ 为了表征草原湿地中甲基汞的生产和生物积累，我提出了一个新的生态系统水平的研究，旨在调查调节草原湿地中甲基汞生产的环境因素。 这项研究将提供新的见解的途径和监管机制参与生物生产，以及随后的摄取，甲基汞进入草原食物网。研究调节草原湿地甲基汞生产的环境因素，对于解决汞甲基化环境控制理解方面的根本差距至关重要，并将为保护栖息在这些脆弱生境中的野生动物种群提供必要的信息。

The microbial methylation of inorganic mercury (HgII) is the most important transformation in the environmental Hg cycle because the product, a neurotoxic, methylated form of Hg (methylmercury; MeHg), is easily bioaccumulated by humans and wildlife.  MeHg production is thought to be mainly mediated by microbes and the amount of Hg methylation in an aquatic environment depends on environmental factors that control microbial population growth or metabolic function.  Factors that promote Hg methylation are particularly important in wetland sediments and prairie wetlands across the Great Plains of North America offer ideal conditions for high rates of Hg methylation.  Prairie wetlands are critical wildlife habitats, providing cover and nesting sites for hundreds of game and non-game wildlife species and containing the some of the most important waterfowl breeding habitat remaining in North America.  Elevated rates of MeHg production could result in significant health and environmental risks to prairie wildlife.  As well, if waterfowl have high MeHg concentrations, hunters and their families consuming prairie wildlife could be exposed to MeHg levels that exceed Hg consumption guidelines.  There is no current information on MeHg in prairie wetlands and this topic raises two important questions: 1. What are the concentrations of MeHg in water, sediment, and biota in different types of prairie wetlands?; and 2. What are the chemical and physical mechanisms that control MeHg production in prairie wetlands?  To characterize the production and bioaccumulation of MeHg in prairie wetlands, I propose a new ecosystem-level study designed to investigate environmental factors regulating MeHg production in prairie wetlands.  This research will provide novel insights on the pathways and regulatory mechanisms involved in biological production, and the subsequent uptake, of MeHg into prairie food webs. Examining environmental factors regulating MeHg production in prairie wetlands is vital to addressing fundamental gaps in understanding of environmental controls on Hg methylation and will provide information necessary to protect wildlife populations inhabiting these vulnerable habitats.