Madeline Patenall (PhD)

Madeline is co-supervised by Dr. Mike Palmer ( https://nwtresearch.com/our-people/mike-palmer)

Project description: The contamination of freshwater resources from nutrient and metal(loid) pollution is of global concern. Frame Lake, located in Yellowknife, Northwest Territories, provides an excellent case study for investigating contaminant and nutrient dynamics. The degradation of this subarctic waterbody from contaminants and nutrients can be attributed to nearby gold mining operations and urbanization. Mining operations have led to the deposition of over half a century of arsenic-bearing atmospheric emissions, and urbanization has intensified nutrient enrichment through landscape alterations and municipal inputs. The cumulative effects of mining operations and urbanization have resulted in eutrophication, metal(loid) contamination, winter anoxia, loss of fish, and reduced recreational value. A rehabilitation project is underway to install an aerator in Frame Lake, which will inject oxygenated water into the deep region of the lake. Research on aeration function in temperate lakes has been conducted. However, a paucity of studies have been directed at examining the effects of aeration on contaminants and nutrients in subarctic waterbodies. Therefore, this work aims to: 1) investigate the impact of aeration on the cycling of arsenic and nutrients between sediments and the water column and 2) assess how aeration influences the composition and abundance of the lower food web. This study capitalizes on the rare opportunity to study the influence of aeration on the water quality of a subarctic, seasonally anoxic lake by integrating geochemical and biological measurements across seasons before and after the aerator installation. Baseline data has been collected since 2020, and sampling of surface waters, sediment porewater, and organisms of the lower food web will continue to be collected monthly to build a high-frequency, multi-season data set. The input of legacy arsenic and nutrients can limit lake rehabilitation for decades; thus, assessing the effectiveness and viability of aeration is essential for Frame Lake and other nutrient-enriched and arsenic-contaminated lakes. Since Frame Lake was historically a gathering place for subsistence and recreational activities, the rehabilitation of this lake is significant for the people of this region.

Associated projects: Rehabilitation of Frame Lake