This work aims to test the performance of the coupled models TELEMAC-3D / AED2 for reproducing over a seasonal time-horizon the complete phytoplankton growthcycle. The study site is a small and shallow urban lake that suffers from repeated and severe harmful algal blooms, located in the east of the Great Paris metropolitan area. The lake is equipped with sensors recording data at high-frequency (every 10 minutes) of water temperature, pH, as well as concentrations of dissolved oxygen, nitrate total chlorophyll and phycocyanin. Such an extensive data set allows to test the model thoroughly against multiple variables and at different time scales. In particular, simulation results were evaluated in terms water temperature at different depths to test the ability of the coupled models to simulate thermal stratification in a shallow water body. High-frequency observations of total chlorophyll, phycocyanin, nitrate, dissolved oxygen concentrations, were used to calibrate the biogeochemical model and evaluate its performance. The analysis of model results highlights a feedback between the coupled models, that can be linked to the dynamic calculation of the light extinction coefficient done in the biogeochemical model. The coupled models AED2 and TELEMAC-3D allow to correctly reproduce the overall seasonal phytoplankton growth in a water body, correctly dispatching biomass among the different phytoplankton groups in particular during summer. Furthermore, the model reproduces correctly the overall dynamics recorded in the study site in terms of dissolved oxygen and nitrate. This corroborates the robustness of the coupled models and of the configuration set up for this study.