Thresholds for mathematical models of microbial interaction

A mathematical model which consists of nutrient, prey and predator for microbial interaction is proposed. The model assumes that the predator may consume its own population and is also incorporated with the mechanism that the nutrient is growth-limiting at low concentrations but may be growth-inhibiting at high concentrations to the prey population. It is demonstrated that intratrophic predation of the top predator has no effect on the dynamics of the lower trophic levels. However, it may alter the dynamics of the higher trophic level.