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

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中的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）是溪流和河流中影响污染物形态和流动性、光穿透、溪流代谢、pH值和水处理效率的主要变量。本研究的目标是（一）改善方法来预测DOM脉冲从上游集水区和（二）提前了解的因素，消耗和改变DOM在其过境通过下游排水网络。 该项目将继续完善一个新的模型，适用于量化DOM从景观转移到源头集水区的河流。该模型将产生径流的土壤径流过程与通过集水区蓄水变化控制陆地DOC的数量和组成的土壤地球化学过程联系起来。该模型将进行测试，对DOM的浓度和组成的测量在几个源头（一阶）流康涅狄格州的法明顿河流域。这些DOM测量也将在第二和第五阶流内的法明顿盆地，从而照亮的方式，DOM的组成和不稳定性演变沿着排水网络。这些观测结果将被用来测试假设的河流网络DOM动态的基础上，交替的经典河流连续体的概念和新提出的脉冲分流conception.This项目将提供研究生和博士后的机会，从事有意义的实验室，现场，定量，理论研究。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合作来影响公众。特别是，我们将与纽黑文公立高中的学生建立一个“分水岭教学车”，将由高中学生在皮博迪博物馆周末载人。

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.