Integrated use of physical and mathematical models to evaluate ecological effects

Nutrient cycling is of central importance in the health and maintenance of all ecosystems, thus it is argued that greater emphasis be placed on the impact of hazardous materials on nutrient cycling. To investigate this concern, flowthrough aquatic microcosms were used in conjunction with a simple, multielement, mathematical model to initiate the development of a large scale model capable of predicting the effects of xenobiotics on ecosystem nutrient cycling. Potential toxicant effects were imposed on the model to determine whether changes in dissolved nutrient concentrations could be noted. Simulation results demonstrated that toxicant effects on dissolved nutrient concentrations were observable. The model also was employed to study the effect of different aufwuchs C : N : P ratios on dissolved nutrient concentrations. Although experimental data indicated that the aufwuchs C : N : P ratio was not constant, the use of constant stoichiometry in the model did not alter its utility.