Collaborative Research: A Stoichiometric Approach to Coupled N and P Cycling in Headwater Streams

通常研究沿溪流长度的养分循环，以了解这些水域中氮(N)或磷(P)的净吸收量。大多数研究都是单独研究氮或磷的循环。在这项研究中，研究人员将开发技术来解决氮和磷在溪流中的耦合循环。这类实验的标准方案包括实验性地提高养分丰度，从而产生不必要的“施肥效应”。在这个研究项目中，研究人员将使用稳定的同位素来确保总（即未受精）元素摄取的测量，并显示耦合摄取如何与溪流藻类和细菌层的元素组成联系在一起。这是一项试验研究，旨在测试这种方法的可行性。面对人类活动导致的氮沉降增加，河流可能是景观吸收氮的重要场所。影响氮保持的生物过程同时受到其他元素循环的影响。这项工作将有助于理解自然过程如何在溪流中提供自我净化，以及氮和磷如何相互作用，作为潜在的限制营养物质来决定水质。这项工作将包括培训博士后、研究生和本科生参与者以及公众宣传。

Nutrient cycling along the length of streams is often studied to understand the net uptake of nitrogen (N) or phosphorus (P) in these waters. Most studies have addressed the cycling of N or P independently. In this study, investigators will develop techniques to address the coupled cycling of N and P in streams. Standard protocols for such experiments involve experimental elevation of nutrient abundance, creating an unwanted 'fertilization effect'. In this research project, the investigators will use stable isotopes to ensure measures of gross (i.e., non-fertilized) elemental uptake and show how coupled uptake is tied to the elemental composition of stream algal and bacterial layers. This is a pilot study to test the feasibility of this approach. Streams may be important sites of N uptake on the landscape in the face of increased N deposition from human activities. Biological processes affecting N retention are simultaneously influenced by the cycling of other elements. This work will contribute to understanding how natural processes provide self-purification in streams and how N and P interact as potentially limiting nutrients to dictate water quality. The work will involve training post-doctoral, graduate, and undergraduate participants and public outreach.