Effect of nonlinear mortality and self-grazing on the dynamics of a marine ecosystem

Abstract

Do the nonlinear terms arising from mortality or self-grazing of zooplankton have significant effect in suppressing limit cycles or autooscillations of marine ecosystem models that are observed under certain conditions? This question is examined with the help of the phase-plane analysis of a class of basic marine ecosystem models. It is found that even a rather small nonlinear term describing nonlinearity in mortality or self-grazing can effectively alter the linear stability conditions and thereby suppress the limit cycles.