COLLABORATIVE RESEARCH: Interactive effects of chronic N deposition, acidification, and phosphorus limitation on coupled element cycling in streams

人类活动使这片土地上的氮素增加了一倍，造成了污染问题，并改变了限制生态系统生物活动的多种营养物质之间的平衡。与此同时，其他干扰，如酸化，以强烈影响陆地和水生生态系统的生产力和健康的方式与氮的富集化相互作用。该项目研究了从大气到土壤再到溪流的连续体中多种元素和干扰(氮、磷、金属和酸化)之间的相互作用。该项目利用了两个独特的实验，在这两个实验中，整个流域在近20年的时间里一直在试验性地用氮和酸进行浓缩。这些流域的一系列新研究考察了土壤中的化学和生物变化如何改变河流吸收、利用和保留氮和磷的能力。这些营养物质的相互作用与影响河流生产力和健康的重要生物过程有关。这项研究解决了一个重要的污染问题，需要一种沿着连接陆地和水生生态系统的流动路径整合生物学和地球化学的方法。这种类型的整合是一种挑战，但对于有效的环境管理、环境研究和科学教学来说是必要的。该项目的结果以及大学和美国林务局研究人员之间的互动将为面临多重污染问题的流域的有效管理提供信息。高中生、本科生和研究生与研究人员和教师合作举办的一系列协作研讨会将促进多学科学习。这项合作将寻求开发一种计算机模拟模型，用于高中和大学理科课程中生物和化学的综合教学。

Human activity has doubled the amount of nitrogen on the landscape, creating a pollution problem and changing the balance among multiple nutrients that limit biological activity in ecosystems. At the same time, other disturbances, such as acidification, interact with nitrogen enrichment in ways that strongly influence the productivity and health of terrestrial and aquatic ecosystems. This project examines the interactions among multiple elements and disturbances (nitrogen, phosphorus, metals, and acidification) along a continuum from the atmosphere through soils to streams. This project takes advantage of two unique experiments in which entire watersheds have been experimentally enriched with nitrogen and acid for nearly two decades. A series of new studies in those watersheds examine how chemical and biological changes in soils alter the ability of streams to take up, use, and retain nitrogen and phosphorus. These nutrient interactions are then related to important biological processes that affect the productivity and health of streams.This research addresses an important pollution problem that requires an approach that integrates biology and geochemistry along flow paths that link the terrestrial and aquatic ecosystems. This type of integration is a challenge, but needed for effective environmental management, environmental research, and science teaching. Results from this project and interactions between university and US Forest Service researchers will inform effective management of watersheds faced with multiple pollution problems. A series of collaborative workshops in which high school, undergraduate, and graduate students work with researchers and teachers will promote multidisciplinary learning. The collaboration will seek to develop a computer simulation model for use in teaching integrated biology and chemistry in high school and college science curricula.