La struttura oceanografica della regione Adriatico Ionica

The Mediterranean is an intercontinental sea located between Europe, Africa and Asia. It is a semienclosed basin with a strong evaporation and a low intake of inland fresh waters. The climate and environmental conditions of the planet Earth affect and are in turn influenced by the marine system as a whole. Consequently, also the cycles of the most biologically relevant elements, such as carbon, nitrogen and phosphorus, are involved in the processes conditioned by the climate and therefore the subject of numerous studies. Because of its central location in the old world, the Adriatic Sea has long been explored and studied. Modern methods of investigation, however, have accelerated the pace of study during the last decade. The Adriatic Sea is the northernmost part of the Mediterranean, extending as far North as 45°47'N. Another crucial element is the large amount of freshwater that the Sea receives from numerous rivers, with total annual average reaching about 5700 m3/s. Of this amount, about 28% (1585 m2/s), comes from a single river, the Po River in the northwestern corner and shallowest part of the basin. The Adriatic Sea bathymetry is characterized by strong transversal and longitudinal asymmetries. The northwestern part of the basin is very shallow, increasing slowly southward, and them sharply reaching about 270 m in the Middle Adriatic Pit (MAP, also called Pomo Depression and Jabuka Pit). To the south of this pit rises the 170 m deep Palagruza Sill separating the MAP from the much deeper and round-shaped South Adriatic Pit. This abyssal depression reaching a maximum depth slightly over 1200 m marks the deepest part of the Adriatic. The cyclonic circulation (anti-clockwise) typical of the Adriatic basin is linked to the prevailing winds (Bora and Scirocco), and plays a fundamental role in the distribution of nutrients carried by rivers, especially along the west coast of the basin. The Italian coast is characterized by less salty waters, and richer in organic and inorganic substance than the typically oligotrophic eastern coast. The western Adriatic coastal areas shows physicochemical characteristics suitable to nursery areas for marine species which then spread to the rest of the basin. Furthermore, during the winter months, the dense water mass (cold and salty water) it could form in North Adriatic. This water mass flows on the bottom and is one of the engines of the thermohaline circulation of the Mediterranean. It is clear that the oceanographic structure of the Adriatic basin plays a key role in the Mediterranean basin. In order to preserve the Adriatic it is important to adopt the best management policies in the Adriatic-Ionian macroregion