A project of the Cooperative Institute for Limnology and Ecosystems Research
In the 1970s, Lake Erie exhibited signs of eutrophication (nutrient overload) and subsequent severe hypoxia (very low oxygen) conditions. These signs were evidenced in massive harmful algal blooms (HAB) that further depleted oxygen available for lake species, notably fish stock. During this same time period, the lake was the recipient of a general multitude of harmful materials including oil, chemical and mineral discharges due to a range of human activity on and off the lake. Without regulatory action, the smallest and most shallow Great Lake was on its way to quickly becoming a "dead zone." Recognizing this problem, and the greater need to protect the lakes bordering both countries, the U.S and Canada coordinated efforts to restore the lake ecosystem to a more balanced state, targeting phosphorus (P) loading inputs in this process. The culmination of this international effort was the Great Lakes Water Quality Agreement. Restrictions were placed on phosphate discharges from point sources and in household items like laundry detergents. These measures appeared to be effective in alleviating the harmful effects of P nutrient overloading. In the mid-1990s however, hypoxic conditions were once again apparent. Given the regulations in place for managing nutrient discharges from point sources, and the current rise and broader scale of hypoxia in the central basin, further assessment is warranted.
The objective of this project is to better understand and forecast the exact conditions that lead to a hypoxic state. Key factors that will be addressed include phosphorus loading, zebra mussel (dreissenid) populations and climate change variability. These indicators will be assessed individually and in combination through an assortment of models. A triad system approach will involve watershed, hypoxia and ecological effects modeling. Ultimately, a set of management and policy options will be produced along with uncertainty assessments and technical guidance for implementation of a given course of action.
This research is funded by the Center for Sponsored Coastal Ocean Research, Coastal Ocean Program of the National Oceanic and Atmospheric Administration.