2004 Volume 16 Issue 2 Pages 171-180
In this paper, conditions of forming colonies and stability and thermodynamic efficiency of microcosm system are discussed by using the mathematical model of microcosm (Individual-Based-Model) reported in the first report. To examine these matters, behaviors of the system were observed after changing characteristics of microorganisms at its mature stage. As the properties of organisms to be changed, we chose the maximum growth rate coefficients of rotifer and chlorella. Changing the parameters means to perturb the ecosystem. In order to change the maximum growth rate coefficients in the model, it is necessary to vary the division active index (energy for multiplication) or the maximum nutrition intake rate. The simulation resulting from a change of these parameters shows that (1) there are two stable phases of the system, (2) the microcosm with colonies is more efficient than the one without colonies, and (3) the strength of the interaction and its frequency among three organisms are important for the colony formation and the stability of the microcosm system.
