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

为了了解这些水域对氮(N)或磷(P)的净吸收，人们经常研究沿溪流长度的营养循环。大多数研究已经独立地解决了N或P的循环问题。在这项研究中，研究人员将开发技术来解决河流中N和P的耦合循环。这类实验的标准方案包括通过实验提高营养丰度，从而产生不必要的“受精效应”。在这一研究项目中，研究人员将使用稳定同位素来确保测量总的(即非受精的)元素吸收，并展示耦合吸收如何与溪流藻类和细菌层的元素组成有关。这是一项试验性研究，旨在测试这种方法的可行性。面对人类活动增加的氮沉降，溪流可能是景观上氮吸收的重要场所。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N和P如何作为潜在的限制营养物质相互作用来决定水质。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.