Macrobenthos and environmental characteristics of the Venice lagoon

Composition, structure and distribution of macrozoobenthic communities in four areas of the Venice lagoon were investigated. Polychaetes and Oligochaetes were the most abundant groups, followed by crustaceans, dipterans and bivalve molluscs. Area differences turned out to be very significant with a maximum diversity index in the central-south part of the lagoon, where there is a maximum influence of water exchanged with the sea. However, no significant differences in organism densities were observed, due to the high variability within each area. The species and their zonation were typical of Mediterranean lagoons. The biotic pattern does not seem related to the concentration of heavy metals in sediments, but rather to the different hydrological regime of the areas closer to the sea compared with areas closed to the mainland, where the influence of river outflow is greate