A test of the assumptions and predictions of recent microalgal growth models with the marine phytoplankter Pavlova lutheri

Abstract

The marine phytoplankter Pavlova lutheri was grown in both batch and continuous culture under various conditions of light and nitrate limitation in order to examine the accuracy of certain assumptions and predictions of growth models. The N : C ratio cells was found to be uniquely related to their relative growth rate. There was no unique relationship, however, between Chl a : C ratios and relative growth rate. Optical absorption coefficients normalized to Chl a were negatively correlated with relative growth rate at a fixed irradiance and positively correlated with irradiance at a fixed relative growth rate when light intensity was varied with neutral‐density filters. Quantum yields were positively correlated with relative growth rate at a fixed irradiance and negatively correlated with irradiance at a fixed relative growth rate. Certain parameters or combinations of parameters which appear in nutrient‐saturated growth models were found to be either independent of relative growth rate at a fixed irradiance or uniquely correlated with relative growth rate. This discovery facilitates extension of nutrient‐saturated growth models to nutrient‐limited conditions.