Beyond Oxygenation: The impact of aerator installation on the chemical and biological recovery of Frame Lake, Yellowknife

The contamination of freshwater resources from nutrient and metal(loid) pollution is a global concern. Recent interest has been placed on the influence of legacy pollutants, which can remobilize in anoxic conditions and have lasting effects on the recovery of aquatic systems. In the Northwest Territories, Frame Lake provides an excellent case study for investigating legacy contaminant dynamics. Urbanization and mining in the region have led to the deposition of over half a century of nutrient and arsenic-bearing atmospheric emissions, resulting in eutrophication, contamination, winter anoxia, and reduced recreational value. However, efforts to rehabilitate Frame Lake have begun. The primary rehabilitation intervention injects oxygenated water into the deep region of the lake (hypolimnetic aeration), increasing winter oxygen concentrations. It is hypothesized that increasing oxygen concentrations will prevent winter anoxia, mitigating the remobilization of legacy elements, such as the nutrient phosphorus and the metal(loid) arsenic, to the overlying water. Additionally, increased oxygen concentrations may promote the biological recovery of the lake by creating habitable overwintering conditions and improved water quality for organisms of the lower food web (zooplankton). With the projected effects of climate change in the Arctic, the prevalence and severity of anoxia in lakes are anticipated to increase in the coming decades. Identifying effective rehabilitation methods mitigating the remobilization of contaminants while promoting biological recovery is paramount.

Presentation Preference: Either

Primary Presenter: Madeline Patenall, Wilfrid Laurier University (madelinepatenall55@gmail.com)

Authors:

Mike Palmer, Aurora Research Institute  (mpalmer@auroracollege.ca)

Derek Gray, Wilfrid Laurier University  (dgray@wlu.ca)