Ecological processes controlling methylmercury production in prairie wetlands

点击翻译按钮获取中文摘要

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.