The areal hypolimnetic oxygen deficit: An empirical test of the model1

Abstract

The areal hypolimnetic oxygen deficit (AHOD) model was tested by examining the relationship between rates of hypolimnetic oxygen depletion and three measures of lake trophic status. Measurements of AHOD were positively correlated with the measured total phosphorus concentration and with annual 14 C pelagic primary production and inversely correlated with mean summer Secchi depth. Because each of the correlations between AHOD and trophic status explained <45% of the observed variation in A HOD values, other factors must also influence the AHOD of a lake. Significant amounts of the residual variation were explained by including the mean depth of the lake and mean hypolimnetic temperature as additional independent variables in a multiple regression analysis. A lake with a thicker or warmer hypolimnion had a higher AHOD than a lake with a shallow or colder hypolimnion. The AHOD model was developed to eliminate the influence o f lake morphometry on interlake comparisons of hypolimnetic oxygen depletion, but it does not do this and a new model must be developed.