Caratteristiche oceanografiche ed ecologiche del Mediterraneo

• Main Authors: G. SPEZIE, R. GUGLIELMO, GUGLIELMO, Letterio, ZAGAMI, Giacomo, MINUTOLI, Roberta
• Other Authors: F. Pellegrino, G., Spezie, Guglielmo, Letterio, Zagami, Giacomo, R., Guglielmo, Minutoli, Roberta
• Format: Book Part
• Language: English; Italian
• Published: Edizioni Scientifiche Italiane (ESI) 2013
• Subjects: Indian; Western Basin; North Atlantic; North Atlantic oscillation
• Online Access: http://hdl.handle.net/11570/2549029

The connection of the entire Mediterranean with the Atlantic Ocean is provided only by the Strait of Gibraltar, which limits exchanges only to the surface layer with an inflow of 1.75 Sv (1 Sv = 1 million m3/s) and an outgoing 1.68 Sv, due to the its depth of 330 m. From a meteorological point of view, the climate on the Mediterranean is closely linked to the North Atlantic baric cell. The variability of this cell is defined by a dimensionless index called «index NAO» (North Atlantic Oscillation), based on the difference of pressure between the minimum of the South Island and the maximum of the Azores High. This value has been calculated on time series data from 1865 to present and assumes positive and negative values cyclically. The circulation of the waters in the Mediterranean has four key points for its dynamics at all depths providing a significant activity: the Gulf of Lions in the western basin, the lower Adriatic, the Aegean Sea north of Crete and the Levantine Sea near Rhodes in the eastern Mediterranean, which is dynamically more active than the western The plankton community of the Mediterranean depends on hydrology and the long evolutionary history of this sea. The lack of a true deep planktonic fauna is the main feature that differentiates the Mediterranean from Oceans. Moreover, the current shape of the Straits of Gibraltar, resulting in significant hydrological differences between the Atlantic and the Mediterranean, enables the adaptation of the Atlantic species to the Mediterranean, so that their spread (Centropages chierchiae, Calanoides carinatus, Pleuromamma borealis, Psudocalanus elongatus, etc.) has been related only to the waters of the Alboran Sea. Although the opening of the Suez Canal in 1869 - an event that has put in communication the Mediterranean with the Indian Ocean - the topographical and hydrological obstacles allowed only few equivalent species (Arietellus pavoninus, Calanopia elliptica, Labidocera madurae, Paraeuchaeta concinna, etc.) to spread into the eastern Mediterranean. A ...