LTREB: Response of a Reservoir Ecosystem to Declining Subsidies of Nutrients and Detritus

这项研究以俄亥俄州的一个分水岭为模型系统，研究了农业实践的变化如何影响下游的河流和湖泊。农业变化包括保护性耕作显著增加，化肥使用量减少，农场动物减少。这些变化正在减少从农场流向溪流的沉积物(土壤)和养分(磷和氮)的数量。这项研究将量化河流中沉积物和营养物质的长期下降，以及下游湖泊随后的反应。据预测，随着营养物质供应的减少，湖泊中的藻类将减少，一种常见的以沉积物为食的鱼类(胆鱼)将因为沉积物输入的减少而减少。这些鱼将大量的营养物质从沉积物循环到水中的藻类。因此，据预测，如果鱼类减少，藻类将进一步减少。美国各地的农业实践也在发生类似的变化，但缺乏有关相关湖泊和溪流的长期反应的数据。由于农业是河流和湖泊非点状沉积物和营养物质污染的主要来源，该项目将为参与水质保护、可持续农业和渔业管理的决策者提供重要信息。此外，该项目将为本科生和研究生提供大量机会，他们将积极参与研究的各个方面。

This research examines how changes in agricultural practices influence downstream streams and lakes, using a watershed in Ohio as a model system. Agricultural changes include a pronounced increase in conservation tillage, reduced fertilizer use and fewer farm animals. These changes are reducing the amounts of sediments (soil) and nutrients (phosphorus and nitrogen) running off from farms to streams. The research will quantify long-term declines in sediments and nutrients in streams, and the subsequent response of a downstream lake. It is predicted that algae in the lake will decrease as their nutrient supply declines, and that a common sediment-eating fish (the gizzard shad) will decline because of decreasing sediment inputs. These fish recycle large quantities of nutrients from sediments to algae in the water. Therefore, it is predicted that if the fish decline, algae will decline even further. Similar changes in agricultural practices are occurring throughout the US, yet there is a lack of data on the long-term responses of associated lakes and streams. Because agriculture is a major source of non-point sediment and nutrient pollution to streams and lakes, this project will provide critical information for decision-makers involved in water quality protection, sustainable agriculture and fisheries management. In addition the project will provide numerous opportunities for undergraduate and graduate students, who will be actively engaged in all aspects of the research.