Studio della variabilità spaziale del fitoplancton nelle lagune di Lesina e Varano (Mar Adriatico).

Dynamics and taxonomy of the phytoplankton communities found in the Lesina and Varano lagoons during an annual monitoring (1997-1998) is discussed. Cell abundances trend is not seasonal; the annual average values is slightly higher in Lesina lagoon (3,42 x 106 cell l-1) than in Varano lagoon (2,56 x 106 cell l-1). From a qualitative point of view, phytoflagellates and diatoms dominate the phytoplankton community, but their dynamics was different in the two compared ecosystems. Phytoplankton blooms, due to the diatom Thalassiosira pseudonana, occur in both the lagoons in different annual periods. In the considered basins the spatial distribution of the phytoplankton communities is associated to the hydrodynamic regime, it is rather homogeneous and 'confinement' phenomena sensu Guelorget & Perthuisot (1983) are not evidenced.