Effects of Al(3+) ions and Cu(2+) ions on microcosms with three different biological complexities

Cu(2+) ions or Al(3+) ions were added to microcosms containing three, four and eight species (S-3, S-4, S-8) at the beginning of the culture, or at the 15th day from the beginning of the culture to determine the production rates (P), the respiration rates (R), and P/R ratios. There was a balance between the oxygen production rates and the oxygen consumption rates in the microcosms (S-4) and (S-8), whereas there was no balance between two quantities in the microcosm (S-3). There were no significant differences in the Cu(2+) and Al(3+) ion concentrations influencing the material cycles and the metabolic balance between the case when the number of species was four and the case when the number of species was eight. It was assumed that the effects concentrations of the chemical substances are not significantly related to the degree of diversity of the constituent species in the microcosms having a balance between production and consumption.