Analyse statistique de l'évolution temporelle de paramètres hydrobiologiques dans les bassins du port du Havre

The study of the spatial structure and temporal evolution of several hydrobiological parameters in a flooding docks system provided a good illustration for the analytical power of a methodology dealing with the statistical processing of multivariate timeseries. This technique can be characterized by prior extraction of the trends, treated separately as ordinary multivariate data, and by a consequent multi-spectral analysis of the residual signais. This procedure offers the advantage of clarifying the analysis of the major features of the phenomenon (i.e. the trends) and unmasking the subtle spatio-temporal structure through the residual signais. The application on Le Havre harbour showed a strong enrichment in nutrients and also a plausible but partial origin for this enrichment in the form of perturbations sources. These can be distinguished by their frequential signature and the associated path of propagation.