SS1.05 How Will Aquatic Ecosystems Respond to Climate Change?
Date: Tuesday, June 11, 2002
Time: 11:15:00 AM
Location: Oak Bay
 
MicheluttiN, Queen's University, Kingston, Canada, 
Douglas, M, , University of Toronto, Toronto, Canada, msvd@geology.utoronto.ca
Smol, J, P, Queen's University, Kingston, Canada, smolj@biology.queensu.ca
 
Limnological and paleolimnological analyses of the two IBP arctic lakes (Char and Meretta): Effects of human-induced eutrophication and recent climatic warming
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From 1968-72, Char and Meretta Lakes (Cornwallis Island, Canadian Arctic) were the sites of several limnological studies conducted during the International Biological Programme (IBP). However, since then, little research has been done on either lake. Since 1992, we’ve sampled both lakes for water chemistry, periphyton, and have collected sediment cores for paleolimnological analyses. In Char Lake, there were no major differences between our water quality data and those collected during the IBP. Our paleolimnological study revealed a shift in the fossil diatom assemblages during the 1990’s (the warmest decade on record). The changes are most consistent with recent climatic warming, and are likely related to a longer growing season and reduced summer ice-cover. Meretta Lake received raw sewage for almost 50 years from the Canadian Department of Transport Base. Our water chemistry measurements showed that decreasing sewage inputs have resulted in marked declines in nutrient concentrations, and the lake would now be classified as oligotrophic. Diatoms in our annual periphyton collections and sediment core assemblages showed that as nutrient levels decreased, there was a shift from eutrophic to oligotrophic assemblages.