Cellular Automata Modelling of Seagrass in the Orbetello Lagoon

This paper describes the evolution in time and space of wigeongrass (Ruppia maritima) meadows in the Orbetello lagoon, in central Italy, where the control of the submerged vegetation, with a critical coexistence between macroalgae and macrophytes, is the key management problem. While macroalgae are liable to cause dystrophic crises, macrophytes oxygenate and stabilise the sediment and thus control the nutrient flux into the water. This model was developed for the Orbetello Lagoon Managerial Office to predict the development of both groups and test the actions to favour macrophytes over macroalgae, in the context of a decision support system. A previous model was developed to account for the interactions between nutrients and the submerged vegetation in a 2-D spatial context, and this paper presents a further refinement, with the dynamics of wigeongrass (Ruppia maritima) including a hydrodynamic model for the water movements and an ecological model describing the interactions between nutrients and the submerged vegetation.