An integrated model for the Orbetello lagoon ecosystem

This paper describes the evolution in time and space of the submersed vegetation in the Orbetello lagoon. This model was developed for the local Lagoon Management Office to predict the development of both macroalgae and macrophytes and test effect of the harvesting decisions. Based on a previous model describing the interactions between nitrogen and the submersed vegetation [Giusti, E., Marsili-Libelli, S., 2005. Modelling the interactions between nutrients and the submersed vegetation in the Orbetello lagoon, Ecol. Model. 184, 141-161], this paper presents several further major improvements introducing the dynamics of phosphorus as a second nutrient, extending the generality of the model to all nutrient conditions and providing a better fit of the observed behaviours, a cellular automaton to describe the dynamics of wigeongrass (Ruppia maritima) and a hydrodynamic model for the water movements. The three models are now synchronized and run in the same context with the Manning friction coefficients acting as a feedback link from the hydrodynamic model to the vegetation dynamics. Another important feature is the wind module, generating synthetic wind time-series required as an input to the hydrodynamic model to produce long-term simulations. The integrated model has been implemented as a stand-alone executable code which can be used as a decision support system. Three-year simulations show the expansion of the existing Ruppia prairies in accordance with the observations.