A simulation model for the annual fluctuation of Zostera marina biomass inthe Venice lagoon

A simulation model was built to describe the growth patterns of Zostera mar ina in an area in the Venice lagoon. The model tracks changes in the above- and below-ground biomass and shoot density and is based on data for Zoster a biomass, net production and growth rates, chemical-physical parameters an d nutrient concentrations in water, sediment and particulate matter. It was assumed that the most important factors controlling Zostera growth and dis tribution are light and temperature, and that Zostera growth was not limite d by nutrient availability. The goal was to simulate biomass production and its seasonal changes as a function of external forcing variables (light, w ater temperature, wind and tide-generated water movements) and internal con trol (plant density). A series of simulation experiments were performed wit h the basic model and its modifications showed that among the most importan t phenomena affecting Zostera growth are: (1) inhibition of production and recruitment of new shoots by high temperature and (2) light attenuation due to seasonal fluctuation and wind- and tide-induced suspension of sediments . (C) 2001 Elsevier Science B.V. All rights reserved.