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

人类活动使地表上的氮含量增加了一倍，造成了污染问题，并改变了多种营养物质之间的平衡，限制了生态系统中的生物活动。与此同时，酸化等其他干扰与氮富集相互作用，强烈影响陆地和水生生态系统的生产力和健康。该项目研究了从大气到土壤到河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。这个项目利用了两个独特的实验，在近20年的时间里，整个流域都用氮和酸进行了实验富集。在这些流域进行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溪流吸收、利用和保留氮磷的能力。这些营养物质的相互作用与影响溪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，需要一种结合生物和地球化学的方法，沿着连接陆地和水生生态系统的流动路径。这种整合是一种挑战，但却是有效的环境管理、环境研究和科学教学所需要的。这个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。一系列由高中生、本科生和研究生与研究人员和教师共同参与的合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，用于在高中和大学科学课程中教授综合生物和化学。

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.