Date of Award



John Van Buren


Aquatic ecosystems are dynamic habitats that must maintain a delicate balance of nutrients to support the organisms within them. When a buildup of nutrients occurs, the body of water becomes ripe for excessive algal growth. The resulting condition is known as an algae bloom. In this thesis I address the increasing occurrence of algae blooms in the Midwestern United States, specifically in Lake Erie, and the impact that these blooms have on aquatic and terrestrial life. Using data collected by the Nature Conservancy, the EPA, and the International Joint Commission, this thesis examines the anthropogenic causes of algae blooms and the far reaching environmental and economic effects that they have. Algae are photosynthetic microorganisms that thrive off of nitrogen and phosphorus, two primary components of agricultural runoff. With high temperatures and abundant sunlight, the density of these cyanobacteria rapidly increases to form a thick green layer on the surface of the water. Effectively, nutrient pollution reduces the dissolved oxygen content of the water and suffocates the aquatic life within. Furthermore, the bodies of the asphyxiated organisms are broken down by microbes that use up even more of the remaining oxygen. The result is a positive feedback loop that creates hypoxic waters and dead zones. For a case study, I explore the impacts of the worst algae bloom in Lake Erie’s history which occurred in 2014. As an interdisciplinary study, this thesis examines the history of cultural eutrophication, the chemistry behind algal blooms, and the economic and political conditions that frame this continuing phenomenon and its possible prevention.