Dissertation Research: Quantifying Nitrogen Spiraling in Anthropogenically Enriched Stream Ecosystems

涉及氮(N)的人为活动正在促进海洋和淡水的富营养化。由于源流是陆地系统和水生系统之间的主要界面，它们是富营养化景观输送氮的重要环节。然而，氮可能通过河流中发生的生态过程被保留或去除。我们将通过比较跨N利用和浓度梯度的研究溪流的保留来研究富集对溪流保留N能力的影响。保留将通过跟踪实验释放到研究流中的N示踪剂的命运来测量。我们将量化与富集相关的生态系统结构（生物存量）和功能（代谢活动）的变化，并评估环境因素（如水文）对N保留的影响。这种将氮富集和保留效率联系起来的方法将增加对逻辑系统中氮负荷的理论和管理方面的理解。

Anthropogenic activities involving nitrogen (N) are contributing to eutrophication in marine and fresh waters. Because headwater streams are the primary interface between terrestrial and aquatic systems, they are an important link in the transport of N from enriched landscapes. However, N may be retained or removed through ecological processes occurring within streams. We will investigate the effects of enrichment on the ability of streams to retain N by comparing retention in study streams that span a gradient of N use and concentration. Retention will be measured by tracking the fate of N tracers experimentally released into study streams. We will quantify changes in ecosystem structure (biotic standing stocks) and function (metabolic activity) associated with enrichment and evaluate the influence of environmental factors (e.g., hydrology) on N retention. This approach to linking N enrichment and retentitive efficiency will increase understanding of theoretical and managerial aspects of N loading to lotic systems.