The Pulse-Shunt Hypothesis: Predicting the Evolution of DOM Composition and DOM Subsidies in Drainage Networks

脉冲分流假说：预测排水管网中 DOM 组成和 DOM 补贴的演变

• 批准号: 1257645
• 负责人: Peter Raymond
• 金额: $ 60万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1257645&HistoricalAwards=false
• 关键词: Pulse; Shunt; Hypothesis; Predicting; Evolution

The transfer of carbon, nutrients, and pollutants from terrestrial environments to streams and the biogeochemical transformations of these constituents within river networks are issues that motivate environmental scientists and water-resource managers. Dissolved organic matter (DOM) is a master variable in streams and rivers that affects contaminant speciation and mobility, light penetration, stream metabolism, pH, and water-treatment efficiency. The goals of this study are to (i) improve approaches for predicting DOM pulses from head-water catchments and (ii) advance understanding of factors that consume and alter DOM during its transit through the downstream drainage network. The project will continue to refine a new model suitable for quantifying DOM transfer from the landscape to streams draining head-water catchments. This model links rainfall-runoff processes that generate stream flow to biogeochemical processes that govern the quantity and composition of terrestrial DOC through changes in catchment-water storage. The model will be tested against measurements of DOM concentration and composition made in several headwater (1st-order) streams of Connecticut's Farmington River Basin. These DOM measurements will also be made in 2nd and 5th-order streams within the Farmington Basin, thereby illuminating the manner in which DOM composition and lability evolve along the drainage network. These observations will be used to test hypotheses for river-network DOM dynamics that are based alternatively on the classical River Continuum concept and a newly proposed Pulse-Shunt concept.This project will provide graduate students and a post-doctoral associate with opportunities to engage meaningfully in lab, field, and quantitative, theoretical research. Equally important, our study will impact the general public by working with the Peabody Museum of Natural History. In particular we will work with New Haven Public high school students to build a "Watershed Teaching Cart" that will be manned by high school students on weekends at the Peabody Museum.

碳、营养物和污染物从陆地环境向河流的转移以及这些成分在河流网络内的生物地球化学转化是激励环境科学家和水资源管理者的问题。溶解有机物 (DOM) 是溪流和河流中的一个主要变量，影响污染物的形态和迁移性、光穿透、溪流代谢、pH 值和水处理效率。本研究的目标是 (i) 改进预测源头流域 DOM 脉冲的方法，以及 (ii) 加深对 DOM 在通过下游排水网络过程中消耗和改变的因素的了解。 该项目将继续完善一个新模型，该模型适用于量化 DOM 从景观到排放源头集水区的溪流的转移。该模型将产生河流的降雨径流过程与通过流域水储存的变化控制陆地 DOC 的数量和组成的生物地球化学过程联系起来。该模型将根据康涅狄格州法明顿河流域的几条源头（一级）溪流的 DOM 浓度和成分测量结果进行测试。这些 DOM 测量还将在法明顿盆地内的二级和五级河流中进行，从而阐明 DOM 组成和稳定性沿排水网络演变的方式。这些观察结果将用于测试河流网络 DOM 动力学的假设，这些假设基于经典的河流连续体概念和新提出的脉冲分流概念。该项目将为研究生和博士后提供有意义地参与实验室、现场和定量理论研究的机会。同样重要的是，我们的研究将通过与皮博迪自然历史博物馆的合作影响公众。特别是，我们将与纽黑文公立高中学生合作建造一辆“分水岭教学车”，周末由高中生在皮博迪博物馆操作。