Modele couple dynamique-ecologie pour la lagune de Bizerte

Abstract

This work concerns the development of a three dimensional hydroecological model based on two nutrient elements, nitrogen and phosphorus.The hydrodynamic model is 3D forced by monthly climatic data of NOAA. The ecological model was developed based on two nutrient elements, nitrogen and phosphorus in interaction with the phytoplankton and zooplancton. The ecological model is made up with two compartments, the water column and the sediment layer. Eight state variables are used to characterize the water column and six state variables for the sediment layer. As a first application, the model was tested on the Bizerte Lagoon. A comparison between simulations and observations showed that the model can reproduce with satisfactory way the observations carried out in the Bizerte Lagoon. Two phytoplankton peaks were simulated. The first one well pronounced in spring and the second one which is less significant in September. The seasonal variation of dissolved oxygen is well simulated. The high concentrations were simulated in winter whereas the low ones in summer.