METAALICUS Part II: The Fate of Mercury in Watersheds and the Recovery of Lake 658 from Elevated Mercury Deposition

METAALICUS 第二部分：流域中汞的命运以及 658 湖从汞沉积升高中的恢复

• 批准号: 0816810
• 负责人: Andrew Heyes
• 金额: $ 82万
• 依托单位: University of Maryland Center for Environmental Sciences
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0816810&HistoricalAwards=false
• 关键词: METAALICUS; Part; II; Fate; Mercury

This project builds on ongoing, large-scale experiments where for six years mercury has been added to whole watersheds including upland forests, wetlands and their associated lakes. The goal is to understand trace metals cycling and to assess how newly deposited substances move through the watershed into wetlands and lakes. In this experiment, additions were originally made to the uplands, wetlands and lakes using different enriched stable isotopes, so that now the pathways of biogeochemical cycling within and among these ecosystems can be determined. Methylmercury levels in fish responded rapidly to the mercury added directly to the lake. But almost all of the mercury applied to the watershed has thus far remained there, through biogeochemical mechanisms of internal ecosystem recycling and retention that remain unknown. Researchers have a unique opportunity to determine the biogeochemical mechanisms responsible for the high degree of retention. Controls over the uptake, storage, transformation and movement of mercury among the vegetation, mineral soil, and soil and sediment organic components will be determined. The results will reveal the time scales at which trace metals are cycled in different types of ecosystems, a major unknown variable critical to modeling future dynamics. Knowing the time scale at which lakes respond to increases in deposition is especially important for the formulation of environmental policy. This interdisciplinary project will have educational impacts through support of graduate students and post-doctoral associates.

该项目建立在正在进行的大规模实验的基础上，六年来，汞已被添加到整个流域，包括高地森林、湿地及其相关湖泊。目标是了解痕量金属循环并评估新沉积的物质如何通过流域进入湿地和湖泊。在该实验中，最初使用不同的富集稳定同位素对高地、湿地和湖泊进行了添加，以便现在可以确定这些生态系统内部和之间的生物地球化学循环途径。鱼类中的甲基汞含量对直接添加到湖中的汞反应迅速。但到目前为止，几乎所有施加到流域的汞都留在那里，通过内部生态系统循环和保留的生物地球化学机制仍然未知。研究人员有一个独特的机会来确定造成高度保留的生物地球化学机制。将确定对植被、矿质土壤以及土壤和沉积物有机成分中汞的吸收、储存、转化和移动的控制。结果将揭示微量金属在不同类型生态系统中循环的时间尺度，这是一个对未来动态建模至关重要的主要未知变量。了解湖泊对沉积增加的反应的时间尺度对于环境政策的制定尤其重要。这个跨学科项目将通过研究生和博士后的支持产生教育影响。