Marked differences in areal hypolimnetic oxygen deficits were found among three depressions of a single lake. These differences were similar to those measured 11 yr before and indicate that regional patterns of nutrient input, production, and eutrophication exist. The patterns are related to lakeshore land use and development. The rate of eutrophication has accelerated across the lake over the 11- yr span. This increase in eutrophication rate would not have been detected had not the hypolimnetic oxygen deficit data also taken into account the differences in hypolimnetic temperatures between the two studies. In fact, without considering temperature, opposite conclusions would have been reached; i.e. that the rate of eutrophication was lessening.