SS1.05 How Will Aquatic Ecosystems Respond to Climate Change?
Date: Tuesday, June 11, 2002
Location: Poster Session - VCC
 
PatrickKL, Cooperative Freshwater Ecology Unit, Laurentian University, Sudbury, Canada, kl_patrick@nickel.laurentian.ca
Gunn, J, M, Cooperative Freshwater Ecology Unit, Laurentian University, Sudbury, Canada, jgunn@nickel.laurentian.ca
Futter, M, , Cooperative Freshwater Ecology Unit, Ontario Ministry of the Environment, Sudbury, CANADA, mfutter@nickel.laurentian.ca
 
PREDICTING FREEZE AND THAW DATES IN SMALL NORTHERN LAKES
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A simple model for predicting ice-on and ice-off dates in 27 small lakes near Sudbury, Ontario was developed using water temperature data measured continuously with a data logger at 1m and 2m below the surface during the 2000-2001 winter. Ice-on dates were calculated using the variance of the average daily temperature and predicted to have occurred when the 5-day variance was less than 0.01 and the recorded temperature was less than 5 C. Ice-off dates were predicted to have occurred when the daily variability was greater than 0.1 at both the 1m and 2m depths and occurred after the predicted freeze date. Internal factors such as maximum depth, mixing depth, and dissolved oxygen content had a higher correlation with freeze dates than external factors such as latitude, fetch and elevation. Internal factors have no correlation on thaw dates. This simple model has potential applications in predicting lake stratification dates and the effect of climate change on ice cover and lake productivity.