Effetti del mixing sulla diversità fitoplanctonica nell'area dello Stretto di Messina

The Straits of Messina represent an "exchange" area between two basins, the Tyrrhenian and the Ionian, characterized by different hydrographic conditions. In late winter period, a multidisciplinary survey was carried out in the Straits area to study phytoplankton abundance and diversity, primary production and enzymatic activities in relation to the water masses (Surface Tyrrhenian, Intermediate Ionian and Messina Mixed Waters). Results highlighted the prevalence of the smallest phytoplankton fractions (<20 ?m) in the entire study area. The Tyrrhenian waters displayed higher values in terms of abundances and enzymatic activities compared to the Ionian waters where higher productivity and diversity, expressed in terms of phylogenetic distance, were observed. Finally, the MMW showed intermediate characteristics between the Tyrrhenian and Intermediate Ionian waters, suggesting that in this period of the year the Straits acted as a "collector" of phytoplankton species from two very different ecosystems.