An Empirical Model to Estimate the Relative Importance of Roots in Phosphorus Uptake by Aquatic Macrophytes

A simple empirical model for predicting the relative contribution of roots in phosphorus uptake by submersed macrophytes is presented. The model requires only approximate dissolved reactive phosphorus (DRP) concentrations in the sediment pore water and overlying water as inputs and can explain 97% of the observed variance. It has the form: P = 99.8/1 + 2.66 (s/w)−0.83 where P is the relative contribution of the root in phosphorus uptake, s and w are the pore water and overlying water DRP concentrations, respectively. The nonspecificity of the model makes it readily applicable to environmental problems related to the role of macrophytes in phosphorus cycling and suggests a similar phosphorus uptake behavior for morphologically different species.