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Mare nostrum. MAR MEDITERRANEO. …in the middle of lands. The only natural link to oceans is constituted by the Gibraltar Strait, which with its 15km of length and 400m of depth, is the only way of communication, with the Atlantic ocean to the west.
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Mare nostrum MAR MEDITERRANEO …in the middle of lands
The only natural link to oceans is constituted by the Gibraltar Strait, which with its 15km of length and 400m of depth, is the only way of communication, with the Atlantic ocean to the west . .
In the eastern sector it is instead linked, since 1869, to the Red Sea, consequently to the Indian Ocean through the artificial Channel of Suez (161 km)
MAR MEDITERRANEO Surface 2 560 000 km2 (included the Black Sea) Lenght ( Gibraltar strait- Libanon coasts) around 3800 km Average Depth 1429 m Maximum Depth, in the Ionian sea, near Matapan cape, Peloponnesum, > 5000 m Coast extension about 46.000 km
The amount of water coming back from rivers and rainfalls is less than that which evaporates : -110 000 m3/s +38000m3/s with a sweet water deficit estimated of approximately 2.500 kilometers cubes (km3) annually If there was’nt the communication with Atlantic ocean The Mediterranean would desappear in some ten thousand years!!
At 500m of depth waters have a temperature that is about 12- 13° C Anyway the superficial strata present ample variations, which depend on seasonal changes: You can have in fact average temperatures of 10 degrees in Jenuary to average temperatures of 25°C in July . At the same time temperature varies from West to East.(15-21) Even salinity is different on the various basins: it varies from 36 to 39 ‰ according to the evaporation and the fluvial contribution. In the Adriatic sea salinity can reach 33 ‰ . The Ionian sea ,on surface, is more salted than Tirrenian sea.
Temperature and salinity differences between Mediterranean waters and Atlantic waters bring about a double current. The Mediterranean waters, denser and heavier, flow in depth and enter the Atlantic through the Gibraltar Strait, whereas the ocean waters get into the Mediterranean flowing on surface. It has been calculated that for the total substitution of waters 7000 years are required.!
The population of the states which look at the Mediterranean sea is about 450 millions of people. • Moreover there is a remarkable touristic presence equal to a third of mondial flow seasonally concentrated on coastal areas particularly on the North Western ones.
Italy divides the Mediterranean sea in two basins ,the western one and the Eastern one. The Mediterranean is subdivided in a certain numbers of independent seas: the Ligurian sea, the Tirrenian Sea and the Sardinia Sea; The Eastern Mediterranean is divided in the Sicily Sea, the Ionian sea and the Adriatic Sea.. Italian coasts stretches along 8500km, and no Italy place is more than 230km away from the coast .
Tentative reconstruction of the Mediterranean evolution for the period Oligocene-middle Miocene. This evolutionary phase has been characterised by a profound tectonic reorganisation of both the western and eastern Mediterranean regions, where the Balearic and Pannonian basins opened up. Extensional tectonics also occurred in the Northern Aegean and Northwestern Anatolian zones.
Tentative reconstruction of the Mediterranean evolution since the late Miocene, This period is characterised by a profound reorganisation of the central and eastern regions, which respectively led to the formation of the Tyrrhenian and Aegean basins. Symbols as in Fig.2. A) Late Miocene: G=Giudicarie trans-pressional fault system, NA, SA=Northern and Southern Apennines, NWT=Northwestern Tyrrhenian, Pe=Pelagian zone, SF=Selli fault. B) Late Pliocene: AE=Apulian escarpment, CR=Crete-Rhodes, CT=Central Tyrrhenian (Magnaghi-Vavilov basin), K=Kefallinia fault, I=Iblean-Ventura microplate, Me = Medina fault, NAF=North Anatolian fault system, SCH=Sicily channel fault system, SE=Siracusa escarpment, SV=Schio-Vicenza Line, Ta=Taormina fault zone, WCB=Western Cretan basin. C) Present: Ca=Calabrian wedge, ECA=External Calabrian Arc, ECB=Eastern Cretan basin, KI=Kithira trough, LP=Lybian promontory, PS=Pliny and Strabo trenches, ST=Southern Tyrrhenian (Marsili basin), VH = Victor-Hensen fault, VR=Vrancea zone.
Calabrian and Tyrrhenian sea geological evolution in the last 10 million years In the same period the Ionian sea and the Adriatic sea were much wider of the present ones. At the end of the Tortonian era, about 10 millions of years ago, the distribution of emerged lands and seas in the area of the mediterranean was very different from how it appears today. In that period in fact the tirrenian sea didn’t exist yet and Calabria, the northern part of Sicily, Sardinia and Corsica were joined together to form an only continental plate
About 7 millions of years ago, during the Miocene, the Sardinian-Corse block began to fracture and from the fractures of the crust a great quantity of basaltic lava leaked out. The fracture widened more and more until forming a deep tectonic hollow which very soon was invaded by waters from the sea. The Tirrenian sea had begun to form, while the eastern part of the old clod, contituted by the present Calabrian–Peloritan block, got away more and more from the Sardinian Corse block.
The Tirrenian sea continues its expansion still today: the present centre of expansion is at about 150 km to the west of the Calabrian Coast where the oceanic crust continues forming in correspondence with the submarine volcan of Marsili. • The old expansion centres are instead represented by the submarine volcans of Magnaghi and Vavilov to the North West regarding Marsili.
While at the West of Calabria the Tirrenian sea was developing ,on its eastern edge, as well as all over the edge of the Apennine, the ancient and heavy oceanic crust, which made up the sounding depth of the Ionian and Adriatic sea began to go downslowly in the mantle. • The sediments which were found on the depth of the sea following the subduction process piled up ones on the others to form huge blankets of covering contributing to the formation of the Apennine Chain.
The sounding depths of the Mediterranean sea are covered with Posidonia prairies. marine plants posidonia oceanica The flowering is instead index of goodhealth for the ecosystem Reduction of posidonia prairies is index of pollution
algae Sea lettuce (Ulva lactuca) Mermaid's cup (Acetabularia mediterranea) The non native introduction of species has influenced the species which were naturally present, sometimes with remarkable impacts: the tropical Caulerpa taxifolia seaweed has had catastrophic effects on the native environment Padina pavonia The present variety of the species is correlated to the inquinameno anthropic pollution. In the lagoon of Venice, for instancee in 1938 were found 141 species of seaweed, 104 in 1962 and only 95 in 1987, and there are so polluted Lagoon areas which render the presence of some species impossible
Reduction of Posidonian prairies • Ligurian sea 20 % • Alicante (Spain) 52 % • Marseille (France) About 90 % • Tolone (France). Completely desappeared • Gabes Gulf (Tunisie) Completely desappeared • Industrial and civil pollution • Alteration of sedimentation due to drag-net fishing • Competition with Caulerpa • from: UNEP-RAC/SPA, 1997a.
sponges Spongia officinalis Axinella polypoides A. verrucosa Spongia agaricina, Haliclona mediterranea some of them are interesting from an economic point of view
Cnidaria (polyp jellyfish corals anemones) The name Cnidaria comes from the Greek word "cnidos", which means stinging nettle. Coral Corallium rubrum Anemone sulcata They are represented by the red coral (facies of Corallium rubrum) and by gorgonians (Eunicella cavolinii, Paramuricea clavata). Yellow gorgonian eunicella cavolinii
Cnidaria In the Mediterranean sea it is very easy to find the sea lung Rhizostoma pulmo . It is the biggest jellyfish of this sea, it reaches 50-60cm of diameter, it has a low itching power. The presence of jellyfishes is index of a good quality of waters.
Cnidaria Actinia carii sea tomato Sea potato Prayeries of actinia
Echinodermata (marine stars , sea urchin) Linckia multifora
Holothuria forskali) Echinodermata Oloturia sea cocumber
Mollusca Cuttlefish Sepia officinalis Octopus vulgaris Todarodes sagittatus
Penaeus Kerathurus Crustacaea ( shellfish) Pink prawn Parapenaeus longirostris Lobster Palinurus elephas Red prawn Aristeus antennatus
Anphibia Bufo bufo Triturus italicus Yila arborea Rana esculenta (frog)
Carthilagineous fish (shark) Scyliorinus canicula Blue shark Prionace glauca Eggs of S.canicula
The ramarkable depth of the Mediterranean sea allows life to some great pelagic species of cetaceans dolphins The marine communities of the Mediterranean are characterized, as regards the Atlantic ones, by a greater number of species but generally with smaller individuals (Mediterranean dwarfism).
MEDITERRANEAN CETACEANS Common rorqual Balaenoptera physalus The immun-soppressive effects of contaminating agents coming from agriculture, industrial activities and demographic increase can have contributed to the decimation of marine mammalians of the Mediterranean. Delphinus delphis
Some species are in danger • (Caretta caretta ) • tortoise Nun seal (monachus monachus)
Owl Athene noctua The scientific name of this bird is that of the greek goddessAthena . A blue eyed owl was the symbol of Athena as we can see in the coins above
Factors that influence the Mediterranean ecosystem •The eutrophization and the pollution coming from agriculture, from industrial activities, from tourism and from demographic increase The introduction of non native species through dregs ship waters, fouling, importations and biological invasions Fishing and excessive exploitation of biological resources. .
La grande lentezza con la quale avviene il ricambio delle acque del Mediterraneo accentua il problema dell’inquinamento The great slowness with which mediterranean water renewal happens icreasaes the pollution problem It is favoured by the continous increase of industrialization and antropization of its coasts Moreover the oil pipe lines, which carry to Europe the oil from the Sahara and the Middle East, run through the Mediterranean. 25 % of mondial oil (about 350.000.000 tonn. annue) pass trough Mediterranean sea
The greater dangers come from the oil tankers (incidents, washing..) The pollution by domestic and industial wastes is serious in certain areas
Environmentalist organizations have often denounced the traffic and the deposit of hazardous wastes. –radiactive scum and chemical pollutants– coming from all Europe, in the Southern Mediterranean, above all along the African coast, in the Lebanon but even in Calabria. (Jolly rosso ship)
The mucillage • The mucilage is constituted by gelatinous heaps produced by fitoplanctonic species (Seaweeds)) that float in the sea rendering it not transparent, moreover, joining to the nets,They make fishing possibility diminish, causing remarkable economic damages The mucilage is constituted by polisaccaridi and other substances secrete from seaweeds (diatomee...) in abnormal quantity. It is not clear if the phenomenon is connected to the pollution of the sea. Actually it existed also in pre-industrial age: scientific signallings exist since 1729 and testimony in the ever existing dialectal names (broma, brommo, sbrommo), all of which have the same root: from the Greek bromos = fetid )
Coastal erosion • It is a quite diffused phenomenon on Italian coasts due to different causes: • Rise of the sea level • Sand removal from rivers and beaches • Buildings on the beach without considering the natural variation of the coastal line
The protection of the Mediterranean Sea from pollution is guaranteed from the Convention of Barcelona of 16 February 1976, adopted under the aegis of the Intergovernment Council of the Environmental Program. It acclimatizes them of N.U. (UNEP) and in order to supply one legal instrument for the performance of the Action Plan for the Mediterranean (MAP) adopted in Barcelona in 1975. Such plan, in the second version approved in 1995, provides objects which are not limited to the single antipollution fight, and that is - to guarantee a durable management of the natural marine and land resources, - to protect the marine atmosphere and the coastal zones preventing pollution as well as reducing and if possible eliminating the contributions of polluting of whichever nature; - to defend , to safeguard and to revalue sites and landscapes of ecological or cultural interest; - to strengthen solidarity among the coastal States of the Mediterranean managing their ir common patrimony and their resources as an advantage for present and future generations; - to contribute to the improvement of life quality.
Fishing • The main types of fishing diffused in our seas are: • drag-net fishing • pelagic fishing • mollusc fishing • small fishing • lagoon fishing
Type of fishing The small fishingis the one carried out by boats not bigger than 10 tons of gross tonnage. The dimensions of the floating allow to be operated with contained work and investment costs. It is impossible to go further than 20 miles from the coast and this let abilities of fishing, of working, conservation and stowage of the product beby no means comparable to those of great boats. In Italy this part of the fleet is of notable importance. There are 8,680 boats of small fishing (1997 are available actually), that represent more than 53% of the national flotilla. Small fishing is particularly present in the Tyirrenian sea with 2.083 boats and in the Adriatic with 1.640 boats. The tools employed for the small fishing are above all position nets, bow-nets and palangari
The draw-net fishing is an important activity in Italy. Only the experience and a deep knowledge of sounding depths consent a ready evaluation of tools and maneuvers to be carried out. The draw net fishing can be carried out with various types of tools that vary in relation to local and regional traditions. The most used tools are the draw-nets, the rapido, the sfogliara. This kind of fishing can be dangerous if done in an uncontrolled way. It menaces the existence of marine species that lives in sounding depths Many environmental associations have required to stop this sort of fishing
Fish to be eaten fresh SOLES, CODS........... GADUS MORRHUA SOLEA VULGARIS MERLUCCIUS MERLUCCIUS Diplodus vulgaris Sparus aurata Dicentrarchus Labrax - Chromis chromis
Fish to be preserved SARDINA PILCHARDUS ENGRAULIS ENCRASICHOLUS THUNNUS THYNNUS