LTREB Renewal: Response of a reservoir ecosystem to declining subsidies of nutrients and detritus

这项研究以俄亥俄州西南部的一个景观为模型系统，研究了农业的变化如何影响河流和湖泊。观察到的农业实践变化包括保护性耕作显著增加，化肥使用量减少，农场动物(特别是猪)减少。这些变化正在减少从农场流失到溪流中的土壤沉积物和化学物质的数量。该项目将量化这些变化以及下游湖泊的后续反应。湖中的藻类数量一直在增加，因为水中较低的沉积物允许更多的阳光穿透。然而，据预测，随着营养物质供应的继续下降，湖泊中的藻类将随着时间的推移而减少。另一种预测是，由于泥沙输入的减少，常见的食沙鱼将会减少。这些鱼将大量的营养从沉积物中循环到藻类中。因此，如果鱼的数量减少，藻类的数量会减少得更快。俄亥俄州正在发生的农业实践变化也在全美范围内发生，但缺乏关于湖泊和溪流长期反应的信息。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关键信息。此外，该项目将为本科生和研究生提供大量的教育机会，他们将积极参与研究的各个方面。最后，一个规划中的分水岭教育中心建成后，将展示这项研究，并帮助教育普通公众陆地上的活动对水质的影响程度。

This research examines how changes in agriculture affect streams and lakes, using a landscape in southwestern Ohio as a model system. Observed changes in agricultural practices include a pronounced increase in conservation tillage, reduced fertilizer use, and fewer farm animals (especially hogs). These changes are reducing the amounts of soil sediment and chemicals that run off from farms into streams. This project will quantify these changes along with the subsequent responses of a downstream lake. The amount of algae in the lake has been increasing, because the lower sediment in the water has allowed more sunlight to penetrate. However, it is predicted that algae in the lake will decrease over time as the nutrient supply continues to decline. Another prediction is that the common sediment-eating gizzard shad will decline because of lower sediment inputs. These fish recycle large quantities of nutrients from the sediments to the algae. Therefore, if the fish decline, algae should decline even more rapidly. Changes in agricultural practices that are occurring in Ohio are also occurring throughout the United States, yet there is a lack of information on the long-term responses of 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 educational opportunities for undergraduate and graduate students, who will be actively engaged in all aspects of the research. Finally, a planned watershed education center, when completed, will showcase this research and help educate the general public on the extent to which activities on land affect water quality.