CAREER: Linked Hydrologic and Atmospheric Fluxes from Riparian Biogeochemical Hotspots

职业：河岸生物地球化学热点的相关水文和大气通量

• 批准号: 0645697
• 负责人: Todd Scanlon
• 金额: $ 44.98万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-04-01 至 2015-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0645697&HistoricalAwards=false
• 关键词: CAREER; Linked; Hydrologic; Atmospheric; Fluxes

Riparian areas are considered to be biogeochemical "hotspots", where biogeochemical reactions and atmospheric emissions are heightened. New monitoring and modeling strategies are needed to develop a process-based understanding of the fluxes and transformations that take place across the terrestrial-aquatic interface. This research centers on applying new technology with micrometeorological methods to bridge the sub-disciplines of land-atmosphere interaction and watershed hydrology. The results will help constrain the rate and timing of biogeochemical processes in riparian hotspots and better define the role of hydrological factors in controlling these fluxes. In particular, this project will focus on cases of nitrogen and mercury cycling in watersheds.In agricultural areas where nitrogen-based fertilizers are applied, significant emissions of nitrous oxide (N2O) can occur. N2O is a potent greenhouse gas that has been implicated in the breakdown of atmospheric ozone. Riparian areas are hypothesized to be hotspots of N2O emissions due to the mixing of high levels of nitrate and dissolved organic carbon. A tunable diode laser trace gas analyzer will measure N2O fluxes in a coastal riparian marsh, where stream discharge and groundwater chemistry will also be monitored. A watershed hydrological model will be integrated with a process-based model of N2O production to interpret and scale up the observations.Mercury concentrations in surface water have been found to be high in even remote locations due to effects of atmospheric deposition. This research will test the theory that riparian areas control stream water mercury concentrations through interacting timescales associated with hydrological transport and chemical transformations. Mercury emissions will be measured, at both point and landscape scales, in an upland riparian wetland in conjunction with aqueous mercury concentrations and stream discharge. The effect of interacting timescales on stream water mercury concentrations will evaluate the impact of transient discharge on mercury fluxes.This research will link with the Schoolyard LTER program at the Virginia Coastal Reserve LTER site, where students from nearby Northampton County High School will take part on summer research projects. A watershed module for the Environmental Science II class will be developed to interface with the students' ongoing water quality monitoring program. University of Virginia undergraduates will take part in this research, through both independent study and distinguished major theses, and through participation in a Field Methods and Data Analysis class. This research involves the training of Ph.D. students, who will have active mentoring roles while carrying out field work and modeling activities. This work will engage a range of students in multi-disciplinary research and in the application of emerging technology.

河岸地区被认为是地球化学“热点”，在那里地球化学反应和大气排放加剧。需要新的监测和建模战略，以发展一个过程为基础的理解的通量和转换发生在陆地-水生界面。本研究以微气象学方法为核心，将新技术应用于陆-气相互作用与流域水文学之间的桥梁。研究结果将有助于限制河岸热点地区生态地球化学过程的速率和时间，并更好地确定水文因素在控制这些通量中的作用。特别是，该项目将重点关注流域中氮和汞循环的案例，在施用氮基肥料的农业地区，可能会产生大量的一氧化二氮（N2 O）排放。N2 O是一种强效温室气体，与大气臭氧的破坏有关。河岸区被假设为N2 O排放的热点，由于高水平的硝酸盐和溶解有机碳的混合。一个可调谐二极管激光痕量气体分析仪将测量一个沿海河岸沼泽地的N2 O通量，在那里还将监测河流排放和地下水化学。将把一个流域水文模型与一氧化二氮生成过程模型结合起来，以解释和扩大观测结果，由于大气沉降的影响，即使在偏远地区，地表水中的汞浓度也很高。这项研究将测试的理论，河岸地区控制河流水汞浓度通过相互作用的时间尺度与水文运输和化学转化。汞排放量将在点和景观尺度上测量，在一个高地河岸湿地结合水汞浓度和流排放。相互作用的时间尺度对溪流中汞浓度的影响将评估瞬时排放对汞flux.This研究的影响将与校园LTER计划在弗吉尼亚州海岸保护区LTER网站，在那里附近的北安普顿县高中的学生将参加夏季研究项目的一部分。环境科学II类的流域模块将开发接口与学生正在进行的水质监测计划。弗吉尼亚大学的本科生将参加这项研究，通过独立的研究和杰出的主要论文，并通过参与现场方法和数据分析类。这项研究涉及博士生的培养。学生，谁将有积极的指导作用，同时进行实地考察和建模活动。这项工作将使一系列学生参与多学科研究和新兴技术的应用。