Abstract. In the paper set of models that take into account various mechanisms for ectokrine regulation of phytoplankton growth are proposed and studied. The considered models are following: with a nonlinear dependence of phytoplankton growth rate on the concentration of the metabolite in the environment; with a metabolite, which increases both the growth rate and mortality of the phytoplankton; with two different metabolites, one of which increases the rate of growth of phytoplankton, and the second - is reduced. These models are modifications of the classical space-time model of the dynamics of phytoplankton, linking change in its density and the concentration of nutrients in space and time, which do not consider the mechanism of ectokrine growth regulation. By the means of the model it has been shown, that the metabolites secreted by algae are able to stabilize the growth of phytoplankton in conditions of excessive nutrient availability.

 

Key words: mathematical modeling, phytoplankton, population dynamics, ectocrine regulation, stability, inhomogeneity.