Physical and Chemical Limnology of Two Mountain Lakes in Banff National Park, Alberta

Abstract

Limnological investigations of an alpine and a lower subalpine lake in Banff National Park from 1966 to 1968 showed that vernal circulation may not extend to the bottom in either lake and that complete autumn circulation may persist for several weeks in both lakes. Winter heat incomes were similar in the lakes, but the summer heat income was much lower for the alpine lake due to heat lost through water renewal. Thermal stratification was more clearly defined in the subalpine lake each year than in the alpine lake. When well-defined chemical stratification occurred, it was short-lived in both lakes. With the exception of phosphate, which was highest in spring and early summer, most changes in chemical composition appeared related to dilution. Very low oxygen concentrations occurred in the bottom water strata of the subalpine lake, but depletion was never severe in the alpine lake. Of the incident visible light 16% penetrated ice and snow cover (1 m) on the alpine lake, but less light reached the water of the lower subalpine lake because of cloudy ice and deeper snow. The trophogenic zone extended to the bottoms of both lakes (about 13 m) for at least part of each year.