Collaborative Research: Effects of Fire and Subsequent Sediment Burial on Sulfur and Mercury Binding in Organic Matter of Forest Soils

合作研究：火灾和随后的沉积物掩埋对森林土壤有机质中硫和汞结合的影响

• 批准号: 0952340
• 负责人: Koren Nydick
• 金额: $ 13.99万
• 依托单位: Mountain Studies Institute
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2011-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0952340&HistoricalAwards=false
• 关键词: Collaborative; Research; Effects; Fire; Subsequent

Intellectual merit: Mercury mobilized by forest fire is accumulating in aquatic organisms in lakes and reservoirs in the Rocky Mountain region. Recent research has focused on mercury emitted to the atmosphere during forest fires, but fire also releases mercury to streams, lakes, and reservoirs. Soil organic matter effectively sequesters most of the mercury deposited in forested watersheds, and fire results in the destruction or erosion of most of the soil organic matter. Fire also results in the development of anoxic, sulfate-reducing conditions in the lakes and reservoirs receiving runoff from fire-disturbed watersheds, and under these conditions, mercury is biologically converted to methylmercury, the form that readily accumulates in aquatic organisms and concentrates up the food chain. In this proposal, research is outlined to examine the effect of fire on the ability of soil organic matter to strongly bind mercury and prevent methylation and bioaccumulation. The research is driven by three hypotheses addressing the transformations caused by fire in the oxidation state of sulfur in soil organic matter and the effect of these changes on mercury binding. The hypotheses are (1) that forest fire increases the oxidation state of sulfur in soil organic matter, (2) that forest fire decreases the strong mercury binding capacity of soil organic matter because of the increase in the oxidation state of the sulfur, and (3) that sediment burial restores, or increases, the strong mercury binding capacity of soil organic matter because of incorporation of hydrogen sulfide in the lake and reservoir sediments. Soil and lake/reservoir sediment sampling will be carried out in watersheds affected by wildfire and prescribed burn. Mercury adsorption to and desorption from the soils, sediments, and extracted organic matter, will be examined using furnace heating to reproducibly assess the effect of heat on sulfur oxidation and mercury binding. In addition, the sulfur and mercury in these materials will be characterized with x?]ray absorption near edge structure (XANES) and extended x?]ray absorption fine structure (EXAFS) spectroscopy.Broader Impact: The broader impacts of this proposal involve three unique features: (1) growth of the San Juan Collaboratory, an initiative of the University of Colorado, Fort Lewis College, the Mountain Studies Institute, and federal, regional, and state land management agencies in the San Juan Mountains region, (2) recruitment of under-represented graduate students through well-established and successful programs at the University of Colorado and University of Illinois, and (3) establishment of the Colorado Water Quality Outreach Center (CWQOC) at the University of Colorado. The San Juan Collaboratory was recently formed to enhance and establish research and educational programs for the southwestern Colorado area. The Colorado Water Quality Outreach Center is being established with the support of the University of Colorado Outreach Committee to provide a state-wide avenue for watershed stakeholder groups and municipalities dealing with water quality problems to seek assistance from faculty and students with water quality problems.

知识分子的优点：在落基山区的湖泊和水库中，林中的汞动员正在积累。最近的研究集中在森林大火期间发出的汞，但火还向溪流，湖泊和水库释放了汞。土壤有机物有效地隔离了沉积在森林流域中的大多数汞，火灾会导致大多数土壤有机物的破坏或侵蚀。火还会导致在湖泊和储层中从扰动的流域中径流的湖泊和储层中发育，在这些条件下，汞在生物学上转化为甲基汞，这种形式很容易在水生生物体中积聚并浓缩食物链。在此提案中，概述了研究，以检查火对土壤有机物强烈结合汞和防止甲基化和生物蓄积的能力的影响。这项研究是由三个假设驱动的，该假设解决了土壤有机物中硫氧化状态中火的转化以及这些变化对汞结合的影响。假设是（1）森林大火在土壤有机物中增加硫的氧化状态，（2）森林大火由于硫的氧化状态的增加而降低了土壤有机物的强汞结合能力，并且（3）沉积物埋藏式埋葬恢复或增加了硫磺的结合液体的结合能力，因为硫磺的结合量增加了水源的液体和液化物的含量。土壤和湖泊/水库沉积物采样将在受野火影响并处方烧伤的流域进行。将使用炉子加热来检查汞对土壤，沉积物和提取的有机物的吸附并解吸，以可重复地评估热量对硫氧化和汞结合的影响。此外，这些材料中的硫和汞将以X的特征？以及圣胡安山区地区的州土地管理机构（2）（2）通过科罗拉多大学和伊利诺伊大学建立的良好和成功的计划，以及（3）在科罗拉多大学的科罗拉多州水质外展中心（CWQOC）建立，招募了代表性不足的研究生。最近成立了圣胡安合作社，以增强和建立西南科罗拉多州地区的研究和教育计划。科罗拉多州的水质外展中心正在科罗拉多大学外展委员会的支持下建立，为在全州范围内为流域利益相关者群体和涉及水质问题的市政当局提供了一条途径，以寻求水质问题的教职员工和学生的帮助。