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.
