Analysis of annual fluctuations of C. nodosa in the Venice lagoon: Modeling approach

A simple simulation modelwas developed to describe the growth trends of Cymodocea nodosa (Ucria) Ascherson based on data sets from the Venice lagoon. The model reproduces the seasonal fluctuations in the above and belowground biomass and in shoot density. The modeling results are in good agreement with data on net production, growth rates and chemical-physical parameters of water. It was assumed that light and temperature are the most important factors controlling C. nodosa development, and that the growth was not limited by nutrient availability. The aim was to simulate biomass production as a function of external forcing variables (light,water temperature) and internal control (plant density). A series of simulation experimentswere performed with the basic model showing that among the most important phenomena affecting C. nodosa growth are: (1) inhibition of production and recruitment of newshoots by high temperature and (2) light attenuation due to seasonal fluctuation.