SIMULATION-MODEL OF ULVA-RIGIDA GROWTH IN SHALLOW-WATER OF THE LAGOON-OF-VENICE

The model presented here points out the possibility of simulating with a mathematical description the life cycle of Ulva rigida C. Ag. in th e Lagoon of Venice. Model simulations allow the assessment of the rela tive importance of factors like light, temperature and nutrient availa bility on U. rigida growth. Particularly, phosphorus internal quota is shown to be always close to its maximum and thus it is never limiting while nitrogen limitation is weak and occurs only in the warm months. The influence of environmental disturbance, here represented by water movement and sediment resuspension induced by climatic events, is int roduced in the model to simulate the observed sharp decline of biomass . Macroalgae biomass accumulation is not described in the model and it s lack is claimed to justify some failure of the model when reproducin g the biomass peak in the growing season. More knowledge is needed in this direction to understand better the influence that such factors co uld have on growth and distribution of U. rigida in shallow water area s of the Lagoon of Venice. The model has been implemented by following the object oriented paradigm. (C) 1997 Elsevier Science B.V.