Comparison of the Phosphorus–Chlorophyll Relationships in Mixed and Stratified Lakes

Data from the literature were used to calculate separate regressions of summer chlorophyll a concentration ([Chl a]) on spring total phosphorus concentration ([TP]) for lakes that remain thermally stratified during the summer and lakes that mix intermittently during the summer. Significant differences were found in the spring [TP] – summer [Chl a] relationships for the two lake types (P < 0.05). The mean ratios of summer [TP] to spring [TP] were also significantly different in stratified and mixed lakes (P < 0.001); this difference is the explanation offered for why the spring [TP] – summer [Chl a] relationships were different in stratified and mixed lakes.