Regional Patterns of Lake Morphology in Relation to Geology

Lake size and shape are important factors determining the function and structure of lake ecosystems. Lake morphology may influence primary and secondary productivity, mixing depth and surface-water temperature which are closely associated with thermal habitat, winterkill, and hypolimnetic suitability of a lake. Geology is also considered as a broad-scale feature that can greatly affect the physical and chemical attributes of aquatic systems, and hence affect the biological communities of those systems. The Precambrian Canadian Shield is a geological feature that encompasses most of northern North America. Geology differs between Shield and off-Shield areas, creating different physical and chemical conditions in aquatic systems. We used lake morphology data to examine regional patterns of lake morphology in Ontario, Canada and specifically to examine the influence of surficial and bedrock geology on regional patterns of lake morphology. Our results suggest that both surficial and bedrock geology play an important role shaping lake morphology. Such results will allow for the incorporation of lake morphology and geology in shaping the character and quantity of harvestable fisheries including lake trout and walleye, at the regional level rather than requiring lake-level understanding.