Hypolimnion Oxygen Consumption in Lakes: Discussion of Productivity and Morphometry Effects

Until recently, hypolimnion oxygen consumption was thought to be a way of comparing the productivity of lakes. This study shows that hypolimnion oxygen represents hypolimnion thickness and temperature as well as productivity. A relationship based on the multiplicative effects of chlorophyll (productivity), thickness, and temperature closely fits the observed oxygen depletion in the Laurentian Great Lakes and in many small lakes. Applied to Lake Erie, the relationship suggests that although a 50% decrease in productivity may result in higher oxygen concentrations, significant oxygen depletion would still occur. The use of oxygen concentrations, depletion rates, or areal deficits to compare the productivity of lakes is not justified without reference to hypolimnion thickness and temperature.