Date of Award


Degree Type


Degree Name

Master of Science




Dr. Katrina Moser



The impacts of European land clearance and agriculture on two southern Ontario kettle lakes were investigated using paleolimnological techniques. Two ~ 50 cm-long sediment cores were retrieved from Edward Lake (shallow, polymictic) and North Pond (deep, dimictic). The cores were dated using 210Pb dating methods. Percentage organics, inferred chlorophyll a and fossil diatom assemblages record striking changes in both lakes following land clearance. Lake sediment records show that increased erosion and nutrient loading resulted in an abrupt, rapid change from an oligotrophic, benthic, clear-water state to a eutrophic, planktonic, turbid-water state. Edward Lake followed the pathway of change predicted by the alternative stable state hypothesis, however, changes at North Pond are more complex and do not. Anthropogenic activities in lake catchments are thought to override climate signals in temperate lakes. However, this research shows that temperature is resulting in increases in chlorophyll a concentrations.



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