PREDICTING END-OF-SUMMER OXYGEN PROFILES IN STRATIFIED LAKES

Mean end-of-summer dissolved oxygen profiles in the hypolimnion of oligotrophic and oligomesotrophic thermally stratified lakes were accurately predicted with a multivariate regression model. The model integrates the effects of lake morphometry, total phosphorus concentration (TP), and initial O2 concentrations at spring turnover to predict mean end-of-summer O2 concentration within individual hypolimnetic strata. Lake morphometry exerts a large influence on O2 profiles and this influence is particularly evident in shallow (<20 m -maximum depth) oligotrophic lakes. Predictions of O2 profiles are sensitive to changes in TP concentrations, with all study lakes predicted to have severely O2-depleted hypolimnions by the end of summer at an epilimnetic TP of only 15 mug.L-1.