Thursday 24 March, 4PM CET
DR. REBECCA DOYLE
ABSTRACT: Lakes in the populous Laurentian Great Lakes region (GLR; southern Canada, northern United States) are important sources of freshwater, hotspots of biodiversity, and regulators of greenhouse gases. However, anthropogenic climate warming and urbanization threaten to alter the water quality and quantity of these lakes. This research establishes a 900- to 1000-year record of environmental change in the GLR. Such baselines are useful for contextualizing recent anthropogenic impacts and for predicting future changes in water quality and quantity. Barry Lake, a small lake in the GLR, is the focus of this study. Small lakes respond more rapidly to environmental change than large lakes, so act as a window through which the future of large lakes may be viewed. The chemical, physical and/or biological characteristics of sediments from four Barry Lake cores were characterized to infer past environmental conditions. These data revealed that the carbon dynamics (e.g., algal growth, carbon burial) of modern Barry Lake differ substantially from conditions observed in the last ~900 years. It was also found that average summer moisture across the GLR is lower today than at any time in the last ~1000 years. These results suggests that, today, small lakes in the GLR are experiencing increased algal growth and heightened evaporative water loss in the summer months. These trends will likely continue unless anthropogenic pressures on lakes in the GLR are curbed. The findings of this research help contextualize recent perturbations to lakes in the GLR and may be used by policymakers to set targets for restoration.