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Composite satellite image of the Mediterranean Sea.

The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by Africa, and on the east by the Levant. The sea is technically a part of the Atlantic Ocean, although it is usually identified as a completely separate body of water.

The name Mediterranean is derived from the Latin mediterraneus, meaning "inland" or "in the middle of the earth" (from medius, "middle" and terra, "earth"). It covers an approximate area of 2.5 million km² (965,000 sq mi), but its connection to the Atlantic (the Strait of Gibraltar) is only 14 km (9 mi) wide. In oceanography, it is sometimes called the Eurafrican Mediterranean Sea or the European Mediterranean Sea to distinguish it from mediterranean seas elsewhere.[1][2]

The Mediterranean Sea has an average depth of 1,500 metres (4,920 ft) and the deepest recorded point is 5,267 metres (about 3.27 miles) in the Calypso Deep in the Ionian Sea.

It was an important route for merchants and travelers of ancient times that allowed for trade and cultural exchange between emergent peoples of the region — the Mesopotamian, Egyptian, Phoenician, Carthaginian, Greek, Illyrian, Levantine, Roman, Moorish, Slavic and Turkish cultures. The history of the Mediterranean region is crucial to understanding the origins and development of many modern societies. "For the three quarters of the globe, the Mediterranean Sea is similarly the uniting element and the centre of World History."[3]

Contents

Name

The term Mediterranean derives from the Latin word mediterraneus, meaning "in the middle of earth" (medius, "middle" + terra, "land, earth"). This is either due to the sea being surrounded by land (especially compared to the Atlantic Ocean) or that it was at the centre of the known world. The Greek name is Mesogeios (Μεσόγειος), "inland, interior" (from μέσο, "middle" + γη, "land, earth")[4].

The Mediterranean Sea has been known by a number of alternative names throughout human history. For example the Romans commonly called it Mare Nostrum (Latin, "Our Sea"). Occasionally it was known as Mare Internum by (Sallust, Jug. 17).

Biblically, it has been called the "Hinder Sea", due to its location on the west coast of the Holy Land, and therefore behind a person facing the east, as referenced in the Old Testament, and sometimes translated as "Western Sea", (Deut. 11:24; Joel 2:20), and also the "Sea of the Philistines" (Exod. 23:31), due to the peoples occupying a large portion of its shores near the Israelites. However, primarily it was known as the "Great Sea" (Num. 34:6,7; Josh. 1:4, 9:1, 15:47; Ezek. 47:10,15,20), or simply "The Sea" (1 Kings 5:9; comp. 1 Macc. 14:34, 15:11).

In Modern Hebrew, it has been called Hayam Hatikhon (הַיָּם הַתִּיכוֹן), "the middle sea", a literal adaptation of the German equivalent Mittelmeer. In Turkish, it is known as Akdeniz, "the white sea". In modern Arabic, it is known as al-Baḥr al-Abyaḍ al-Mutawassiṭ (البحر الأبيض المتوسط), "the White Middle Sea." And, lastly, in Islamic and older Arabic literature, it was referenced as Baḥr al-Rūm (بحر الروم), or "the Roman/Byzantine Sea."

History

As a sea around which some of the most ancient human civilizations were arranged, it has had a major influence on the history and ways of life of these cultures. It provided a way of trade, colonization and war, and was the basis of life (via fishing and the gathering of other seafood) for numerous communities throughout the ages.

The combination of similarly-shared climate, geology and access to a common sea has led to numerous historical and cultural connections between the ancient and modern societies around the Mediterranean.

Geography

A satellite image taken from the side of the Strait of Gibraltar. At left, Europe: at right, Africa.

The Mediterranean Sea is connected to the Atlantic Ocean by the Strait of Gibraltar on the west and to the Sea of Marmara and the Black Sea, by the Dardanelles and the Bosporus respectively, on the east. The Sea of Marmara is often considered a part of the Mediterranean Sea, whereas the Black Sea is generally not. The 163 km (101 mi) long man-made Suez Canal in the southeast connects the Mediterranean Sea to the Red Sea.

Large islands in the Mediterranean include Cyprus, Crete, Euboea, Rhodes, Lesbos, Chios, Kefalonia, Corfu, Naxos and Andros in the eastern Mediterranean; Sardinia, Corsica, Sicily, Cres, Krk, Brač, Hvar, Pag, Korčula and Malta in the central Mediterranean; and Ibiza, Majorca and Minorca (the Balearic Islands) in the western Mediterranean.

The climate is a typical Mediterranean climate with hot, dry summers and mild, rainy winters. Crops of the region include olives, grapes, oranges, tangerines, and cork.

Extents

The International Hydrographic Organization defines the limits of the Mediterranean Sea as follows:[5]

The Mediterranean Sea is bounded by the coasts of Europe, Africa and Asia, from the Strait of Gibraltar on the West to the entrances to the Dardanelles and the Suez Canal on the East.

It is divided into two deep basins as follows:

Western Basin

On the West. A line joining the extremities of Cape Trafalgar (Spain) and Cape Spartel (Africa).

On the Northeast. The West Coast of Italy. In the Strait of Messina a line joining the North extreme of Cape Paci (15°42'E) with Cape Peloro, the East extreme of the Island of Sicily. The North Coast of Sicily.

On the East. A line joining Cape Lilibeo the Western point of Sicily (37°47′N 12°22′E / 37.783°N 12.367°E / 37.783; 12.367), through the Adventure Bank to Cape Bon (Tunisia).

Eastern Basin

On the West. The Northeastern and Eastern limits of the Western Basin.

On the Northeast. A line joining Kum Kale (26°11'E) and Cape Helles, the Western entrance to the Dardanelles.

On the Southeast. The entrance to the Suez Canal.

On the East. The coasts of Syria and Palestine.

Oceanography

Predominant currents for June.

Being nearly landlocked affects the Mediterranean Sea's properties; for instance, tides are very limited as a result of the narrow connection with the Atlantic Ocean. The Mediterranean is characterized and immediately recognized by its deep blue color.

Evaporation greatly exceeds precipitation and river runoff in the Mediterranean, a fact that is central to the water circulation within the basin.[6] Evaporation is especially high in its eastern half, causing the water level to decrease and salinity to increase eastward.[7] This pressure gradient pushes relatively cool, low-salinity water from the Atlantic across the basin; it warms and becomes saltier as it travels east, then sinks in the region of the Levant and circulates westward, to spill over the Strait of Gibraltar.[8] Thus, seawater flow is eastward in the Strait's surface waters, and westward below; once in the Atlantic, this chemically distinct "Mediterranean Intermediate Water" can persist thousands of kilometers away from its source.[9]

Bordering countries

Map of the Mediterranean Sea.

Twenty-two modern states have a coastline on the Mediterranean Sea. They are:

Turkey and Egypt are transcontinental countries. The southernmost islands of Italy, the Pelagie islands, are geologically part of the African continent.

Several other territories also border the Mediterranean Sea (from west to east):

Andorra, Jordan, Portugal, San Marino, the Vatican City, Macedonia and Serbia[10] although they do not border the sea, are often considered Mediterranean countries in a wider sense due to their Mediterranean climate, fauna and flora, and/or their cultural affinity with other Mediterranean countries.

Capital cities of sovereign countries and major cities with populations larger than 200,000 people bordering the Mediterranean Sea are: Malaga, Cartagena, Alicante, Valencia, Palma, Barcelona, Marseille, Nice, Monaco, Genoa, Rome, Naples, Palermo, Catania, Messina, Valetta, Taranto, Bari, Venice, Trieste, Ljubljana, Split, Dubrovnik, Durrës, Patras, Athens, Thessaloniki, Istanbul, Izmir, Antalya, Mersin, Tarsus, Adana, Lattakia, Tripoli (Lebanon), Beirut, Haifa, Tel Aviv, Ashdod, Gaza, Port Said, Damietta, Alexandria, Benghazi, Tripoli (Libya), Sfax, Tunis, Annaba, Algiers and Oran.

Subdivisions

According to the International Hydrographic Organization (IHO), the Mediterranean Sea is subdivided into a number of smaller waterbodies, each with their own designation (from west to east)[5]:

Burjeslam Beach, Latakia Syria.
A view of Raouché off the coast of Beirut, Lebanon.
A view across the Oludeniz, Turkey.
Island of Mljet, Croatia.
Rocky coast of Darnah, Libya.
Mediterranean coast in Israel.
Sunrise and rains over the Mediterranean, seen from the breakwaters of the village of Loutra (pop. 63) on the Greek island of Kythnos.

Other seas

Although not recognized by the IHO treaties, there are some other seas whose names have been in common use from the ancient times, or in the present:

Other features

Many of these smaller seas feature in local myth and folklore and derive their names from these associations. In addition to the seas, a number of gulfs and straits are also recognised:

Geology

The geologic history of the Mediterranean is complex. It was involved in the tectonic break-up and then collision of the African and Eurasian plates. The Messinian Salinity Crisis occurred in the late Miocene when the Mediterranean dried up. Geologically the Mediterranean is underlain by oceanic crust.

The Mediterranean Sea has an average depth of 1,500 metres (4,920 ft) and the deepest recorded point is 5,267 meters (about 3.27 miles) in the Calypso Deep in the Ionian Sea. The coastline extends for 46,000 kilometres (28,600 mi). A shallow submarine ridge (the Strait of Sicily) between the island of Sicily and the coast of Tunisia divides the sea in two main subregions (which in turn are divided into subdivisions), the Western Mediterranean and the Eastern Mediterranean. The Western Mediterranean covers an area of about 0.85 million km² (0.33 million sq mi) and the Eastern Mediterranean about 1.65 million km² (0.64 million sq mi).

Tectonic evolution

The geodynamic evolution of the Mediterranean Sea was provided by the convergence of European and African plates. This process was driven by the differential spreading along the Atlantic ridge, which led to the closure of the Tethys Ocean and eventually to the Alpine orogenesis. However, the Mediterranean also hosts wide extensional basins and migrating tectonic arcs, in response to its land-locked configuration.

According to a report published by Nature in 2009, scientists think that the Mediterranean Sea was mostly filled during a time period of less than two years, in a major flood (the Zanclean flood) that happened approximately 5.33 million years ago, in which water poured in from the Atlantic Ocean and through the Strait of Gibraltar, at a rate three times the current flow of the Amazon River.[11]

Eastern Mediterranean

In middle Miocene times, the collision between the Arabian microplate and Eurasia led to the separation between the Tethys and the Indian oceans. This process resulted in profound changes in the oceanic circulation patterns, which shifted global climates towards colder conditions. The Hellenic Arc, which has a land-locked configuration, underwent a widespread extension for the last 20 Myr due to a slab roll-back process. In addition, the Hellenic Arc experienced a rapid rotation phase during the Pleistocene, with a counterclockwise component in its eastern portion and a clockwise trend in the western segment.

Central Mediterranean

The opening of small oceanic basins of the central Mediterranean follows a trench migration and back-arc opening process that occurred during the last 30 Myr. This phase was characterized by the counterclockwise rotation of the Corsica-Sardinia block, which lasted until the Langhian (ca.16 Ma), and was in turn followed by a slab detachment along the northern African margin. Subsequently, a shift of this active extentional deformation led to the opening of the Tyrrenian basin.

Western Mediterranean

Since Mesozoic to Tertiary times, during convergence between Africa and Iberia, the Betic-Rif mountain belts developed. Tectonic models for its evolution include: rapid motion of Alboran microplate, subduction zone and radial extensional collapse caused by convective removal of lithospheric mantle. The development of these intramontane Betic and Rif basins led to the onset of two marine gateways which were progressively closed during the late Miocene by an interplay of tectonic and glacio-eustatic processes.

Paleoenvironmental analysis

Its semi-enclosed configuration makes the oceanic gateways critical in controlling circulation and environmental evolution in the Mediterranean Sea. Water circulation patterns are driven by a number of interactive factors, such as climate and bathymetry, which can lead to precipitation of evaporites. During late Miocene times, a so-called "Messinian Salinity Crisis" (MSC hereafter) occurred, which was triggered by the closure of the Atlantic gateway. Evaporites accumulated in the Red Sea Basin (late Miocene), in the Carpatian foredeep (middle Miocene) and in the whole Mediterranean area (Messinian). An accurate age estimate of the MSC—5.96 Ma—has recently been astronomically achieved; furthermore, this event seems to have occurred synchronously. The beginning of the MSC is supposed to have been of tectonic origin; however, an astronomical control (eccentricity) might also have been involved. In the Mediterranean basin, diatomites are regularly found underneath the evaporite deposits, thus suggesting (albeit not clearly so far) a connection between their geneses.

The present-day Atlantic gateway, i.e. the Strait of Gibraltar, finds its origin in the early Pliocene. However, two other connections between the Atlantic Ocean and the Mediterranean Sea existed in the past: the Betic Corridor (southern Spain) and the Rifian Corridor (northern Morocco). The former closed during Tortonian times, thus providing a "Tortonian Salinity Crisis" well before the MSC; the latter closed about 6 Ma, allowing exchanges in the mammal fauna between Africa and Europe. Nowadays, evaporation is more relevant than the water yield supplied by riverine water and precipitation, so that salinity in the Mediterranean is higher than in the Atlantic. These conditions result in the outflow of warm saline Mediterranean deep water across Gibraltar, which is in turn counterbalanced by an inflow of a less saline surface current of cold oceanic water.

The Mediterranean was once thought to be the remnant of the Tethys Ocean. It is now known to be a structurally younger ocean basin known as Neotethys. The Neotethys formed during the Late Triassic and Early Jurassic rifting of the African and Eurasian plates.

Paleoclimate

Because of its latitudinal position and its land-locked configuration, the Mediterranean is especially sensitive to astronomically induced climatic variations, which are well documented in its sedimentary record. Since the Mediterranean is involved in the deposition of eolian dust from the Sahara during dry periods, whereas riverine detrital input prevails during wet ones, the Mediterranean marine sapropel-bearing sequences provide high-resolution climatic information. These data have been employed in reconstructing astronomically calibrated time scales for the last 9 Ma of the Earth's history, helping to constrain the time of past Geomagnetic Reversals[12]. Furthermore, the exceptional accuracy of these paleoclimatic records have improved our knowledge of the Earth's orbital variations in the past.

Ecology and biota

Turqueta beach, in the Spanish island of Menorca.

As a result of the drying of the sea during the Messinian Salinity Crisis,[13] the marine biota of the Mediterranean are derived primarily from the Atlantic Ocean. The North Atlantic is considerably colder and more nutrient-rich than the Mediterranean, and the marine life of the Mediterranean has had to adapt to its differing conditions in the five million years since the basin was reflooded.

The Alboran Sea is a transition zone between the two seas, containing a mix of Mediterranean and Atlantic species. The Alboran Sea has the largest population of Bottlenose Dolphins in the western Mediterranean, is home to the last population of harbour porpoises in the Mediterranean, and is the most important feeding grounds for Loggerhead Sea Turtles in Europe. The Alboran sea also hosts important commercial fisheries, including sardines and swordfish. In 2003, the World Wildlife Fund raised concerns about the widespread drift net fishing endangering populations of dolphins, turtles, and other marine animals.

Environmental threats

Biodiversity

Invasive species

The opening of the Suez Canal in 1869 created the first salt-water passage between the Mediterranean and Red Sea. The Red Sea is higher than the Eastern Mediterranean, so the canal serves as a tidal strait that pours Red Sea water into the Mediterranean. The Bitter Lakes, which are hyper-saline natural lakes that form part of the canal, blocked the migration of Red Sea species into the Mediterranean for many decades, but as the salinity of the lakes gradually equalized with that of the Red Sea, the barrier to migration was removed, and plants and animals from the Red Sea have begun to colonize the Eastern Mediterranean. The Red Sea is generally saltier and more nutrient-poor than the Atlantic, so the Red Sea species have advantages over Atlantic species in the salty and nutrient-poor Eastern Mediterranean. Accordingly, Red Sea species invade the Mediterranean biota, and not vice versa; this phenomenon is known as the Lessepsian migration (after Ferdinand de Lesseps, the French engineer) or Erythrean invasion. The construction of the Aswan High Dam across the Nile River in the 1960s reduced the inflow of freshwater and nutrient-rich silt from the Nile into the Eastern Mediterranean, making conditions there even more like the Red Sea and worsening the impact of the invasive species.

Invasive species have become a major component of the Mediterranean ecosystem and have serious impacts on the Mediterranean ecology, endangering many local and endemic Mediterranean species. A first look at some groups of exotic species show that more than 70% of the non-indigenous decapods and about 63% of the exotic fishes occurring in the Mediterranean are of Indo Pacific origin,[14] introduced into the Mediterranean through the Suez Canal. This makes the Canal as the first pathway of arrival of “alien” species into the Mediterranean. The impacts of some lessepsian species have proven to be considerable mainly in the Levantine basin of the Mediterranean, where they are replacing native species and becoming a “familiar sight”.

According to the International Union for Conservation of Nature definition, as well as Convention on Biological Diversity(CBD) and Ramsar Convention terminologies, they are alien species, as they are non native (non-indigenous) to the Mediterranean Sea, and they are outside their normal area of distribution which is the Indo-Pacific region. When these species succeed in establishing populations in the Mediterranean sea, compete with and begin to replace native species they are “Alien Invasive Species”, as they are an agent of change and a threat to the native biodiversity. Depending on their impact, Lessepsian migrants are either alien or alien invasive species. In the context of CBD, “introduction" refers to the movement by human agency, indirect or direct, of an alien species outside of its natural range (past or present). The Suez Canal, being a artificial (man made) canal, is a human agency. Lessepsian migrants are therefore “introduced” species (indirect, and unintentional). Whatever wording is chosen, they represent a threat to the native Mediterranean biodiversity, because they are non-indigenous to this sea. In recent years, the Egyptian government's announcement of its intentions to deepen and widen the canal have raised concerns from marine biologists, fearing that such an act will only worsen the invasion of Red Sea species into the Mediterranean, facilitating the crossing of the canal for yet additional species.[15]

Arrival of new tropical Atlantic species

In recent decades, the arrival of exotic species from the tropical Atlantic has become a noticeable feature. Whether this reflects an expansion of the natural area of these species that now enter the Mediterranean through the Gibraltar straight, because of a warming trend of the water caused by Global Warming; or an extension of the maritime traffic; or is simply the result of a more intense scientific investigation, is still an open question. While not as intense as the “lessepsian” movement, the process deserves to be studied and monitored.

Sea-level rise

Europe may be less threatened by sea-level rise than many developing country regions. However, coastal ecosystems do appear to be threatened, especially enclosed seas such as the Baltic, the Mediterranean and the Black Sea. These seas have only small and primarily east-west orientated movement corridors, which may restrict northward displacement of organisms in these areas.[16] Sea level rise for the next century (2100) could be between 30 and 100 cm and temperature shifts of a mere 0.05-0.1°C in the deep sea are sufficient to induce significant changes in species richness and functional diversity.[17]

Pollution

Pollution in this region has been extremely high in recent years. The United Nations Environment Programme has estimated that 650 million tons of sewage, 129,000 tons of mineral oil, 60,000 tons of mercury, 3,800 tons of lead and 36,000 tons of phosphates are dumped into the Mediterranean each year.[18] The Barcelona Convention aims to 'reduce pollution in the Mediterranean Sea and protect and improve the marine environment in the area, thereby contributing to its sustainable development.'[19]

Many marine species have been almost wiped out because of the sea's pollution. One of them is the Mediterranean Monk Seal which is considered to be among the world's most endangered marine mammals.[20]

The Mediterranean is also plagued by marine debris. A 1994 study of the seabed using trawl nets around the coasts of Spain, France and Italy reported a particularly high mean concentration of debris; an average of 1,935 items per square kilometre. Plastic debris accounted for 76%, of which 94% was plastic bags.[21]

Shipping

Some of the world’s busiest shipping routes are in the Mediterranean Sea. It is estimated that approximately 220,000 vessels of more than 100 tonnes cross the Mediterranean Sea each year – about one third of the world’s total merchant shipping. These ships often carry hazardous cargo, which if lost would result in severe damage to the marine environment.

The discharge of chemical tank washings and oily wastes also represent a significant source of marine pollution. The Mediterranean Sea constitutes 0.7 percent of the global water surface and yet receives seventeen percent of global marine oil pollution. It is estimated that every year between 100,000 and 150,000 tonnes of crude oil are deliberately released into the sea from shipping activities.

Approximately 370 million tonnes of oil are transported annually in the Mediterranean Sea (more than 20 percent of the world total), with around 250 to 300 oil tankers crossing the Sea every day. Accidental oil spills happen frequently with an average of 10 spills per year. A major oil spill could occur at any time in any part of the Mediterranean.[17]

Tourism

With a unique combination of pleasant climate, beautiful coastline, rich history and diverse culture the Mediterranean region is the most popular tourist destination in the world - attracting approximately one third of the world’s international tourists.

Tourism is one of the most important sources of income for many Mediterranean countries. It also supports small communities in coastal areas and islands by providing alternative sources of income far from urban centres. However, tourism has also played major role in the degradation of the coastal and marine environment. Rapid development has been encouraged by Mediterranean governments to support the large numbers of tourists visiting the region each year. But this has caused serious disturbance to marine habitats such as erosion and pollution in many places along the Mediterranean coasts.

Tourism often concentrates in areas of high natural wealth, causing a serious threat to the habitats of endangered Mediterranean species such as sea turtles and monk seals. It is ironic that tourism in this region is destroying the foundations of its own existence. And it is inevitable that the tourists will leave the Mediterranean as it becomes more depleted of its natural beauty.[17]

Overfishing

Fish stock levels in the Mediterranean Sea are alarmingly low. The European Environment Agency says that over 65 percent of all fish stocks in the region are outside safe biological limits and the United Nations Food and Agriculture Organisation, that some of the most important fisheries – such as albacore and bluefin tuna, hake, marlin, swordfish, red mullet and sea bream - are threatened.

There are clear indications that catch size and quality have declined, often dramatically, and in many areas larger and longer-lived species have disappeared entirely from commercial catches.

Large open water fish like tuna have been a shared fisheries resource for thousands of years but the stocks are now dangerously low. In 1999 Greenpeace published a report revealing that the amount of bluefin tuna in the Mediterranean had decreased by over 80 percent in the previous 20 years and government scientists warn that without immediate action the stock will collapse.

Aquaculture

Aquaculture is expanding rapidly - often without proper environmental assessment – and currently accounts for 30% of the fish protein consumed worldwide. The industry claims that farmed seafood lessens the pressure on wild fish stocks, yet many of the farmed species are carnivorous, consuming up to five times their weight in wild fish.

Mediterranean coastal areas are already over exposed to human influence, with pristine areas becoming ever scarcer. The aquaculture sector adds to this pressure, requiring areas of high water quality to set up farms. The installation of fish farms close to vulnerable and important habitats such as seagrass meadows is particularly concerning.

Aquaculture production in the Mediterranean also threatens biodiversity through the introduction of new species to the region, the impact of the farms' organic and chemical effluents on the surrounding environment and coastal habitat destruction.

See also

References

  1. ^ http://www.ifremer.fr/lobtln/OTHER/ext_abstr_East_Sea_workshop_TLM.pdf
  2. ^ http://ec.europa.eu/research/headlines/news/article_09_03_19_en.html
  3. ^ Georg Wilhelm Friedrich Hegel The Philosophy of History, p. 87, Dover Publications Inc., 1956 ISBN 0486201120; 1st ed. 1899
  4. ^ entry μεσόγαιος at Liddell & Scott
  5. ^ a b "Limits of Oceans and Seas, 3rd edition". International Hydrographic Organization. 1953. http://www.iho.shom.fr/publicat/free/files/S23_1953.pdf. Retrieved 19 December 2009.  
  6. ^ Pinet, Paul R. (1996) Invitation to Oceanography, St Paul, MN: West Publishing Co., ISBN (3rd ed.), p.202
  7. ^ Pinet, p. 206
  8. ^ Pinet, pp. 206–7
  9. ^ Pinet, p. 207
  10. ^ [1]. For example, Andorra, San Marino and Serbia are members of the International Mediterranean Games Committee and participate at the Mediterranean Games.
  11. ^ Mediterranean Sea filled in less than two years: study, AFP, December 9, 2009
  12. ^ FJ, Hilgen. Astronomical calibration of Gauss to Matuyama sapropels in the Mediterranean and implication for the Geomagnetic Polarity Time Scale, 104 (1991) 226-244 Earth and Planetary Science Letters, 1991.[2]
  13. ^ Hsu K.J., "When the Mediterranean Dried Up" Scientific American, Vol. 227, December 1972, p32
  14. ^ >"IUCN Guidelines for the Prevention of Biodiversity Loss Caused by Alien Invasive Species". International Union for Conservation of Nature. 2000. http://www.issg.org/infpaper_invasive.pdf. Retrieved 2009-08-11.  
  15. ^ Galil, B.S. and Zenetos, A. (2002). A sea change: exotics in the eastern Mediterranean Sea, in: Leppäkoski, E. et al. (2002). Invasive aquatic species of Europe: distribution, impacts and management. pp. 325-336.
  16. ^ Nicholls, R.J.; Klein,R.J.T. (2005). Climate change and coastal management on Europe's coast, in: Vermaat, J.E. et al. (Ed.) (2005). Managing European coasts: past, present and future. pp. 199-226.
  17. ^ a b c http://www.greenpeace.org/international/campaigns/oceans/marine-reserves/the-mediterranean/mediterranean-other-threats
  18. ^ http://www.explorecrete.com/nature/mediterranean.html
  19. ^ http://europa.eu/scadplus/leg/en/lvb/l28084.htm
  20. ^ http://www.monachus-guardian.org/factfiles/medit01.htm
  21. ^ >"Marine Litter: An analytical overview". United Nations Environment Programme. 2005. http://www.unep.org/regionalseas/marinelitter/publications/docs/anl_oview.pdf. Retrieved 2008-08-01.  

External links


1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

MEDITERRANEAN SEA. The Mediterranean is all that remains of a great ocean which at an early geological epoch, before the formation of the Atlantic, encircled half the globe along a line of latitude. This ocean, already diminished in area, retreated after Oligocene times from the Iranian plateau, Turkestan, Asia Minor and the region of the north-west Alps. Next the plains of eastern Europe were lost, then the AraloCaspian region, southern Russia and finally the valley of the Danube. The " Mediterranean region," as a geographical unit, includes all this area; the Black Sea and the Sea of Marmora are within its submerged portion, and the climate of the whole is controlled by the oceanic influences of the Mediterranean Sea. Professor Suess, to whom the above description is due, finds that the Mediterranean forms no exception to the rule in affording no evidence of elevation or depression within historic times; but it is noteworthy that its present basin is remarkable in Europe for its volcanic and seismic activity. Submarine earthquakes are in some parts sufficiently frequent and violent as seriously to interfere with the working of telegraph cables. Suess divides the Mediterranean basin into four physical regions, which afford probably the best means of description: (I) The western Mediterranean, from Gibraltar to Malta and Sicily, enclosed by the Apennines, the mountains of northern Africa, and of southern and south-eastern Spain (Cordillere betique). (2) The Adriatic, occupying the space between the Apennines and the Dinaric group (Suess compares the Adriatic to the valley of the Brahmaputra). (3) A part surrounded by the fragments of the Dinaro-Taurus arch, especially by Crete and Cyprus. This includes the Aegean and the Black Sea, and its margin skirts the south coast of Asia Minor. These three parts belong strictly to Eurasia. (4) Part of the coastal region of IndoAfrica, terraced downwards in successive horizontal planes from the Shot, reaching the sea in the Little Syrte, and continuing to the southern depressions of Syria. Malta and Gozo are the only islands of the Mediterranean which can be associated with this section, and, per contra, the mountain chain of north-west Africa belongs to Eurasia. Murray (1888) estimates the total area of the Mediterranean at 813,000 sq. m. Karstens (1894) breaks it up into parts as follows: Western Mediterranean 841,593 Sicilian-Ionian basin 767,658 Greece and Levant basin 769,652 Adriatic Sea 130,656 Total.. 2 ,5 0 9,559 „ A more recent calculation by Kriimmel gives the total area as 2,967,570 sq. km. or 1,145,830 sq. M. (See Ocean.) Murray estimates the total surface of the Mediterranean drainage area, with which must be included the Black Sea, at 2,934,500 sq. m., of which 1,420,800 are Eurasian and 1,513,800 are African. The principal rivers entering the Mediterranean directly are the Nile from Africa, and the Po, Rhone and Ebro from Europe.

Depth.

Fathoms.

Area.

Sq. Miles.

Volume.

Cub. Miles.

0 100 .

. 201,300

80,950

100 500 .

. 251,650

220,850

500-1000 .

81,300

189,200

1000-2000 .

. 263,250

217,050

Over 2000 .

. 15,500

1,750

813,000

709,800

Volume. Mean Depth.

Cub. Km. Fathoms.

Western Mediterranean

.

1,356,512

881

Sicilian-Ionian basin .

.

, 4 ,549

885

Levant .

.

, ,599

793

Adriatic Sea .

31,844

133

The physical divisions of the Mediterranean given above hold good in describing the form of the sea-bed. The western Mediterranean is cut off by a bank crossing the narrow strait between Sicily and Cape Bon, usually known as the Adventure Bank, on which the depth is nowhere 200 fathoms. The mean depth of the western basin is estimated at 881 fathoms, and the deepest sounding recorded is 2040 fathoms. In the eastern Mediterranean the mean depth is nearly the same as in the western basin. The Sicilian-Ionian basin has a mean depth of 885 fathoms, and the Levant basin, 793 fathoms. Deep water is found close up to the coast of Sicily, Greece, Crete and the edge of the African plateau. The steepest slope observed occurs off the island of Sapienza, near Navarino, where 1720 fathoms has been obtained only 10 miles from land. In 1897 the ship " Washington " obtained depths of 2220 fathoms in the middle of the eastern Mediterranean; and the Austrian expeditions in the " Pola " discovered in the " Pola Deep " (35° 44' N., 21 45' E.), south-west of Cape Matapan, a maximum depth of 2046 fathoms. Between these two deep areas a ridge runs in a north-westerly direction 550 fathoms from the surface - possibly a projection from the African plateau. Another bank i ioo fathoms from the surface runs south from the east end of Crete, separating the Pola Deep from the depths of the Levant basin, in which a depth of 1960 fathoms was recorded near Makri on the coast of Asia Minor. The later expedition of the " Pola " discovered the " Rhodes Deep " (36° 5' N., 28° 36' E.), with a maximum depth of 2110 fathoms: this deep is closed to the south-east by a ridge running south-east, over which the depth is 1050 fathoms. Off the coast of Syria the " Pola "obtained four soundings of more than 1100 fathoms, and between Cyprus and the coast of Asia Minor only two over 550 fathoms. Murray gives the following figures for the areas and volumes of the Mediterranean at different depths: which gives a mean depth over all of 768 fathoms. The following table is due to Karstens: Kriimmel gives the total volume of the basin as 4,249,020 cubic kilometres or 1,019,400 cubic statute miles, and the mean depth as 782 fathoms. (See Ocean.) Meteorology. - As already stated, the " Mediterranean region " forms a distinct climatic unit, chiefly due to the form and position of the Mediterranean Sea. The prevailing winds in this region, which the sea traverses longitudinally, are westerly, but the sea itself causes the formation of bands of low barometric pressure during the winter season, within which cyclonic disturbances frequently develop, while in summer the region comes under the influence of the polar margin of the tropical high pressure belt. Hence the Mediterranean region is characteristically one of winter rains, the distinctive feature becoming less sharply defined from south to north, and the amount of total annual fall increasing in the same direction. The climate becomes more continental in type from west to east, but there are great local irregularities - the elevated plateaus of Algeria and Spain cause a rise of pressure in winter and delay the rainy seasons: the rains set in earlier in the west than in the east, and the total fall is greater. Temperature varies greatly, the annual mean varying from 56° F. to 77° F. In the west the Atlantic influence limits the mean annual range to about 10°-12° F., but in the east this increases to 36° and even 40°. Autumn is warmer than spring, especially in the coastal regions, and this is exaggerated in the eastern region by local land winds, which replace the cool sea-breezes of summer: overcoats are ordinarily worn in Spain and Italy till July, and are then put aside till October. Local winds form an important feature in nearly all the coast climates of the Mediterranean, especially in winter, where they are primarily caused by the rapid change of temperature from the sea to the snow-clad hinterlands. Cold dry winds, often of great violence, occur in the Rhone valley (the Mistral), in Istria, and Dalmatia (the Bora), and in the western Caucasus. In summer a north-west " trade " wind, the Maestro, occurs in the Adriatic. The Sirocco is a cyclonic wind characteristic of the winter rainy season; in the Adriatic it is usually accompanied by cloud and moisture, often by rain. In Sicily and southern Italy the Sirocco occurs at all seasons; it is a dry, dusty wind from south-east or south-west. The dust is chiefly of local origin, but partly comes from the Sahara. Similar winds are met with in Spain (the Leveche), but they reach their greatest development in the Simooms of Algeria and Syria, and the Khamsin of Egypt.

Temperature

The mean surface temperature of the waters of the Mediterranean falls from south-east, where it is over 11111123° F., to north-west, the average at the coast of the Gulf of Lyons being 60°. The isothermal of 65° runs from Gibraltar to the north of Sardinia, and thence by the Strait of Messina to the Gulf of Corinth. A similar distribution is found loo fathoms from the surface, temperature falling from 60° in the Levant to 55° east of Gibraltar. At 200 fathoms temperature falls in the same way from 58° to 55°, but below 250 fathoms temperatures are practically uniform to the bottom, 55 5° in the western basin and 56 5° in the eastern. The bottom temperature observed in the Pola Deep was 56.3°.

Salinity

In the extreme west the salinity of the surface water is about 36 3 per mille, and it increases eastwards to 37 6 east of Sardinia and 39 0 and upwards in the Levant. Observations of salinity in the depths of the western Mediterranean are very deficient, but the average is probably between 38 o and 38 5. In the eastern basin the " Pola " expedition observed salinities of 38 7 to 39 o to the east of a line joining Cape Matapan with Alexandria, and 38 2 to 38 7 to the west of it. The salter waters apparently tend to make their way westwards close to the African coast, and at the bottom the highest salinities have been observed south of Crete. Evnitzki states that the saltest water of the whole basin occurs in the Aegean Sea.

Circulation

There is little definite circulation of water within the Mediterranean itself. In the straits joining it with the Atlantic and the Black Sea the fresher surface waters of these seas flow inwards to assist in making good the loss by evaporation at the surface of the Mediterranean, and in both cases dense water makes its way outwards along the bottom of the channels, the outflowing currents being less in volume and delivery than the inflowing. Elsewhere local surface currents are developed, either drifts due to the direct action of the winds, or streams produced by wind action heaping water up against the land; but these nowhere rise to the dignity of a distinct current system, although they are often sufficient to obliterate the feeble tidal action characteristic of the Mediterranean. Dr Natterer, the chemist of the " Pola " expeditions, has expressed the opinion that the poverty of the pelagic fauna is solely due to the want of circulation in the depths.

sq. km. „ Deposits. - A great part of the bottom of the Mediterranean is covered with blue muds, frequently with a yellow upper layer containing a considerable proportion of carbonate of lime, chiefly shells of pelagic Foraminifera. In many parts, particularly in the eastern basin, a calcareous or siliceous crust, from half an inch to three inches in thickness, is met with; and Natterer suggested that the formation of this crust may be due to the production of carbonate of ammonium where deposits containing organic matter are undergoing oxidation, and the consequent precipitation of carbonate of lime and other substances from the waters nearer the surface. This view, however, has not met with general acceptance. (H. N. D.)


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English

Proper noun

the Mediterranean Sea

  1. The sea between Europe and Africa.

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The Mediterranean Sea.


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File:Mediterranean
Mediterranean Sea

The Mediterranean Sea is the body of water that separates Europe, Africa and Asia.

The Mediterranean Sea is connected to the Atlantic Ocean by a narrow passage called the Strait of Gibraltar. It is almost completely surrounded by land, on the north by Europe, on the south by North Africa, and on the east by the Middle East. It covers around 2.5 million km² (965 000 mi²). To the east it connects to the Sea of Marmara and the Black Sea, by the Dardanelles and the Bosporus respectively. The Sea of Marmara is often considered a part of the Mediterranean Sea, whereas the Black Sea is generally not. The 163 km (101 mi) long man-made Suez Canal in the southeast connects the Mediterranean Sea to the Red Sea.

History

As a sea around which some of the most ancient human civilizations were arranged, it has had a major influence on the history and ways of life of these cultures. It provided a way of trade, colonization and war, and was the basis of life (via fishing and the gathering of other seafood) for numerous communities throughout the ages. The combination of similarly shared climate, geology and access to a common sea has led to numerous historical and cultural connections between the ancient and modern societies around the Mediterranean.

Above all, it was the superhighway of transport in ancient times, allowing for trade and cultural exchange between peoples of the region — Phoenicians, Egyptians, Carthaginians, Greeks, Romans, and the Middle East (Arab/Persian/Semitic) cultures. The history of the Mediterranean is important in understanding the origin and development of Western civilization.

Oceanography

Being nearly landlocked affects the Mediterranean Sea's properties. Tides are limited by the narrow connection with the Atlantic Ocean. The water is saltier, partly because of evaporation. The Mediterranean has a deep blue color.

Evaporation greatly exceeds precipitation and river runoff in the Mediterranean, a fact that is central to the water circulation within the basin.[1]p202 Evaporation is especially high in its eastern half, causing the water level to decrease and salinity to increase eastward.[1]p206 This pressure gradient pushes relatively cool, low-salinity water from the Atlantic across the basin; it warms and becomes saltier as it travels east, then sinks in the region of the Levant and circulates westward, to spill over the Strait of Gibraltar.[1]p206/7 Thus, seawater flow is eastward in the Strait's surface waters, and westward below; once in the Atlantic, this chemically distinct "Mediterranean Intermediate Water" can persist thousands of kilometers away from its source.[1]p207

References

  1. 1.0 1.1 1.2 1.3 Pinet, Paul R. (1996), [Expression error: Unexpected < operator Invitation to Oceanography] (3rd ed.), St Paul, MN: West, ISBN 0314063390 
bjn:Laut Tangahrue:Середоземне море







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