Adriatic Sea

Adriatic Sea area

Location of the Adriatic Sea.

The Adriatic Sea is located in the North-Central Mediterranean Sea, between 39°46’57” and 45°48’18” latitude Nord and 12°17’14.81″ and 19°34’33.86″ longitude East. The Adriatic Sea is a 800 km-long and 200 km-wide basin, connected to the Eastern Mediterranean Sea through the Strait of Otranto. The surface area of the Adriatic Sea is about 138600 km2 and its volume 35000 km3, representing about the 5% of the entire Mediterranean Sea.

 

 

The Adriatic Sea is divided into three basins: the Northern section, or Northern Adriatic, characterized by an average depth of about 35 m, average salinity of 37-38‰ and average temperature of 25°C; the central section, or Middle Adriatic, characterized by an average depth of about 140 m and the Southern section, or Southern Adriatic, characterized by a wide depression more than 1200 m deep, average salinity of 38.4-38.9‰ and average temperature of 18°C .

Adriatic Sea

The superficial currents basins of the Adriatic sea.

The Adriatic Sea is characterized by a cyclonic superficial circulation: the waters from the Strait of Otranto flow northward along the Croatian east coast and flow southward along the Italian west coast. Cyclonic gyres could be formed in each of the three basins, with different intensity depending to the season and the freshwater inputs. Moreover, the Northern sector of the Adriatic Sea, characterized by a broad and shallow shelf, with depth less than 50 m and exposed to the north-easterly Bora wind, is a site of dense waters formation (the most important source of the bottom water of the Eastern Mediterranean).
The Adriatic Sea is a semi-enclosed basin, marked by seasonal and long-term fluctuations of oceanographic and biological conditions, mainly due to atmospheric forcing, freshwater discharges, variable intrusion of high salinity waters and a very variable and complex circulation.
The Adriatic sea is the most productive basin of the entire Mediterranean Sea, along the western coast the high nutrient load is responsible for high primary production (>100 up to 350 gC m-2y-1).

The Adriatic Sea is included under the Barcelona Convention for the Protection of Mediterranean Sea and in the Habitat Directive. It is populated by benthic, demersal and pelagic species of ecological and commercial interest. Furthermore, the Adriatic Sea holds several coastal and deep-sea habitats (e.g. lagoons, coralligenous concretions, canyons, submarine landslides, seamounts, fossil and alive deep-sea corals) considered of of natural and international interest.

The Adriatic sea experienced intensifying anthropogenic-driven and global environmental alterations in the last 50 years. Due to inputs from the Po river, Adriatic sediments were typically characterized by strong accumulation of organic loads, and locally experienced hypoxic crises. However, during last few years it has been observed an increasing of water temperature and a partial regression of the eutrophication led to decreasing primary production and evident effects on plankton. This was maybe due to the decreasing of the riverine discharge and to an alteration in nutrients inputs (nitrogen and phosphorus).
Alterations of the ecosystem functioning resulted also in appearance of red tides, intensification of mucilage formation, possibly triggering the spread of pathogens.
The North-Central Adriatic Sea constitutes the widest continental shelf in the Mediterranean Sea and is of great value for fishing within the Italian and the European context. Important changes in landings have been registered in this area, with a dramatic increase from the mid 1970s to the mid 1980s, followed by marked fluctuations in landings until catches progressively declined from late 1980s to the present; primarily because of the decrease in small pelagic fish, especially of European anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus). Moreover, various target demersal species have been reported as overexploited and important amounts of discards are produced. Other activities are tourism, aquaculture, maritime transport.