Influenza della marea sul fitoplancton e su alcune variabili ambientali in Valle di Brenta (Laguna di Venezia)

During eight seasonal samplings, samples of phytoplankton were collected near the channels feeding the Valle di Brenta, located in the Southern area of the Lagoon of Venice. The microalgal composition was varied: the Diatoms were present in all seasons, and irregularly but sometimes quantitatively abundant also Euglenophyceae, Cryptophyceae and Chlorophyceae were found. The Dinophyceae, living mostly in the seawater, underwent a great regression. The microflagellates, characterized by organisms belong to different classes and difficult to identify for their small sizes, were abundantly present. A high specific diversity was always registered with rare blooms. A constant correspondence between phytoplanktonic abundance and direction of tide current was not observed. The different phytoplankton values registered in the sampling stations were due to the different water origin and, consequently to the environmental conditions