Modeling eutrophication kinetics in reservoir microcosms

This study addresses the question of how a general seasonal eutrophication model, WASP5, can handle daily phytoplankton and nutrient dynamics in perturbed microcosms for 1- to 2-week periods of time. It is intended to explore both the interpretative and the predictive capabilities of conventional kinetic formulations. The general method adopted in this study is to first apply EUTRO5, a component of WASP5, to a well-behaved microcosm, calibrating the parameter values and reformulating equations if necessary. Next, the calibrated model is subjected to testing in other microcosm experiments, with altered parameter values if necessary. Model performance is further explored through sensitivity analyses to try to “explain” the observed kinetics in the experiments, and a two-way ANOVA is finally applied to the simulated vs observed evolution curves of the three main variables, i.e. chlorophyll a, soluble-P and ammonia-N in all experiments and microcosms studied.