Ecological processes controlling methylmercury production in prairie wetlands

无机汞的微生物甲基化(HgII)是环境汞循环中最重要的转化，因为其产物是一种神经毒性的甲基化形式的汞(甲基汞；甲基汞)，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调节的，水环境中汞的甲基化程度取决于控制微生物种群增长或代谢功能的环境因素。这些促进汞甲基化的因素在北美大平原的湿地沉积物和草原湿地中尤为重要，为汞甲基化的高比率提供了理想的条件。北美草原湿地是关键的野生动物栖息地。为数百种野味和非野味野生动物提供覆盖和筑巢场所，并包含北美现存的一些最重要的水鸟繁殖栖息地。甲基汞生产量的增加可能会导致草原野生动物面临巨大的健康和环境风险。此外，如果水禽的甲基汞浓度较高，猎人及其家人食用草原野生动物的甲基汞水平可能会超过汞消费指南。*目前草原湿地中没有关于甲基汞的信息，这个话题提出了两个重要的问题：1.不同类型草原湿地的水、沉积物和生物群中的甲基汞浓度是多少？2.控制草原湿地中甲基汞产生的化学和物理机制是什么？为了表征草原湿地中甲基汞的产生和生物积累，我提出了一项新的生态系统层面的研究，旨在调查草原湿地中调节甲基汞产生的环境因素。这项研究将为生物生产中涉及的途径和调控机制以及随后甲基汞在草原食物网中的吸收提供新的见解。研究调节草原湿地甲基汞生产的环境因素对于消除对汞甲基化的环境控制方面的根本差距至关重要，并将提供保护生活在这些脆弱栖息地的野生动物种群所需的信息。

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.