Modifications in recent models of phytoplankton growth: Theoretical developments and experimental examination of predictions

Abstract

A simple modification of the theoretical model of phytoplankton growth developed by Shuter (1979) permits description of both nutrient-limited and light-limited growth with a single set of equations for all irradiances. The modified model retains the predictive ability of the original Shuter model with respect to nutrient-limited nutrient: carbon ratios, and is shown to be identical to the model of Kiefer & Mitchell (1983) with respect to predictions concerning growth rate (μ) as a function of irradiance, light-limited respiration rates (r) as a function of μ, and chlorophyll: carbon ratios as a function of μ + r. The only area in which the predictions of the modified Shuter and Kiefer-Mitchell models differ is in the relationship between r and μ under nutrient-limited conditions. This difference is shown to be sufficiently small as to be difficult to detect experimentally.