DISSERTATION RESEARCH: Nonlinear effects of nutrient loading on stream nutrient processing: Are they driven by shifts in biofilm community dynamics?

从邻近陆地表面进入河流的营养物质要么被河流生物保留，要么被输送到下游。这项研究将调查土地利用如何影响覆盖溪流中大多数基质的藻类和微生物薄垫（生物膜）对营养物质的去除。随着全球土地利用变化的不断增加，了解生物膜组成的变化如何影响营养物的去除是至关重要的。研究通常集中在改变氮(N)、磷(P)或碳等单一资源可用性的后果上。土地利用的许多变化导致多种资源的可用性发生变化，因此有必要更好地了解同时变化的多种资源对生物膜群落组成的潜在相互作用。该奖项支持的实验将通过控制实验室内N+P和碳浓度，量化河流生物膜的组成和功能在响应不同资源梯度时发生的变化。随着景观日益受到农业、城市化和工业化的影响，了解河流生态系统对养分负荷的反应将有助于预测地表水的养分保留和输出能力。这项研究将确定生物膜群落的相互作用如何改变养分循环，并告知土地管理者土地利用变化的潜在后果。

Nutrient loading to streams from adjacent land surfaces can either be retained by the stream organisms or exported downstream. This research will investigate how land use influences nutrient removal by the thin mats of algae and microbes that cover most substrates in streams (biofilms). Understanding how changes in biofilm composition can affect nutrient removal is essential as land use change continues to increase worldwide. Studies have often focused on the consequences of altering availability of a single resource such as nitrogen (N), phosphorus (P), or carbon. Many changes in land use result in changes in the availability of more than one resource, thus, there is a need to better understand the potential interactions of simultaneously varying multiple resources on biofilm community composition. Experiments supported by this award will quantify the changes that occur in the composition and function of stream biofilm in response to varied resource gradients by manipulating N+P and carbon concentrations in experimental chambers. As landscapes are increasingly impacted by agriculture, urbanization, and industrialization, understanding the response of stream ecosystems to nutrient loading will help predict nutrient retention and export capacity of surface waters. This research will identify how biofilm community interactions alter nutrient cycling and inform land managers of potential consequences of changes in land use.