A Test of Hypotheses to Explain the Sigmoidal Relationship between Total Phosphorus and Chlorophyll a Concentrations in Canadian Lakes

Abstract

We tested five hypotheses to explain the sigmoidal relationship between total phosphorus (TP) and chlorophyll a (Chl a), two assuming that the nonlinearity is an artifact of various measurement biases and three assuming that it is based on underlying ecological interactions. Our first hypothesis was rejected; accounting for differences in extraction protocol of Chl a among published studies did not affect the sigmoidality. Our second hypothesis …