Nonlinear time series analysis and modeling: Water quality applications

The dynamics of a nutrient web model subjected to a periodic input were examined as a surrogate for a water quality system. As the period of the driving input increased, the model moved from periodic behavior to irregular dynamics that were chaotic. The power spectra of the time series were estimated and the more irregular time series displayed behavior consistent with a chaotic time series. A nonlinear time series analysis technique method, the deterministic versus stochastic (DVS) algorithm was applied to the time series to demonstrate that algorithm's ability to distinguish between noisy periodic motion and truly chaotic dynamics.