The Mediterranean is the world’s largest inland sea. It lies between the continents of Europe and Africa and is bounded on the east by the westernmost stretches of Asia. Its length is about 4,025 km (2,500 mi), its average width 805 km (500 mi), and its area about 2,965,500 sq km (1,145,000 sq mi). The greatest depth, 5,092 m (16,706 ft), is in the Matapan Trench of the Ionian Basin. The mean depth is about 1,525 m (5,000 ft).
The name is derived from the Latin medius (“middle”) and terra (“earth,” or “land”), indicating that the sea was once believed by the civilizations of that region to be at the center of the world. Bordering the Mediterranean are, counterclockwise, Morocco, Algeria, Tunisia, Libya, Egypt, Israel, Lebanon, Syria, Turkey, Greece, Albania, Montenegro, Bosnia and Hercegovina, Croatia, Slovenia, Italy, Monaco, France, and Spain. Island states within the sea are Malta and Cyprus. Other large islands, from west to east, are the Balearic Islands, Corsica, Sardinia, Sicily, and Crete, lying in the Ligurian, Tyrrhenian, Adriatic, Ionian, and Aegean seas. The Mediterranean is linked to the Atlantic Ocean by the Strait of Gibraltar, to the Black Sea by the Turkish straits (Dardanelles and Bosporus), and to the Red Sea by the Suez Canal.
The Mediterranean shores were settled in prehistoric times. Ever since, many people have entered the region from the continental interiors, mixed their physical and cultural traits, and developed new ones. The entire coastline and continental shelves are littered with the ruins of earlier civilizations. Some of them developed into great empires, expanding far beyond the basin itself. For millennia, the products of the region have been exported throughout the known world, and the Mediterranean countries have, in turn, served as a vast receiving house for staples and luxury goods. Because of its critical location at the juncture of three continents, and because of the “stepping-stone” islands, the many fine harbors, and the rich cities and countries on its shores, the Mediterranean Sea has long been of strategic importance. The Strait of Gibraltar, the Turkish straits, and the Suez Canal are among the world’s most important marine passageways.
Geology
The present Mediterranean Sea is a remnant of the ancient Tethys Seaway that once extended as far north as the Danube Basin and possibly as far east as the Aral Sea. The seabed is divided by a ridge into eastern and western basins, and then subdivided into several lesser basins and seas. The Adriatic, Ionian, and Aegean seas all have abyssal plains beyond the continental shelf, which averages less than 24 km (15 mi) in width. The smaller basins are separated by submarine ridges, such as that between Crete and eastern Libya. Another, only about 305 m (1,000 ft) below the surface, connects Spain and Morocco. The generally steep and rocky coasts are often deeply indented and interrupted by small, scattered plains. Although most streams entering the sea carry considerable amounts of sediment, the only large deltas are those of the Nile, Rhone, and PO rivers. Many of the islands are the peaks of volcanoes, some of which are still active. The entire Mediterranean basin is tectonically active with frequent earthquakes, particularly in Greece and Turkey.
Climate
The Mediterranean climate, one of the most distinctive in the world, is characterized by mild, wet winters and hot, long, dry summers. The size, position, and configuration of the Mediterranean produce a variety of local modifications that range from desertic to humid mountain climates. Precipitation generally decreases toward the south and east and ranges from more than 2,540 mm (100 in) per year near Dalmatia to less than 255 mm (10 in) annually in parts of North Africa. Temperatures also decrease toward the east and increase toward the south.
Hydrology and Marine Life
Of the numerous rivers that flow into the Mediterranean, the largest is the Nile in Egypt. Other important rivers are the Ebro in Spain; the Rhone in France; the Arno, Tiber, Po, and Isonzo in Italy; Vardar, Striman, and Nestos in Greece; and Gediz and Menderes in Turkey. All the water from the rivers and the rainfall, however, could not maintain the level of the sea, which would drop about 1,400 mm (55 in) per year without a great deal of inflow from the Atlantic. A surface current, flowing from the south along the African coast, enters the Mediterranean through Gibraltar. Underneath, a smaller and slower current, about 305 m (1,000 ft) deep, flows into the Atlantic. Water balance is also maintained by a similar–although smaller–inflow and outflow through the Turkish straits. The general pattern of surface currents is counterclockwise, with many local exceptions. Only at Gibraltar and on the east coast of Tunisia is the tidal range greater than 914 mm (3 ft). Surface temperatures vary seasonally, from about 5 degrees C (41 degrees F) in February in the northern Adriatic to 31 degrees C (88 degrees F) in August off the coast of Libya. Because of considerable evaporation, the water is much more saline than that of the Atlantic Ocean or the Black Sea. Salinity increases from west to east, toward the end of the dry season, and away from river mouths.
The floor of the Mediterranean is covered with yellow brown sediments–about 50 percent lime and the rest clay and sand–to an approximate thickness of 2,740 m (9,000 ft). Underlying this layer is blue mud. Fine riverine muds overlie these strata near river mouths and are carried great distances by currents, thus retarding the development of deltas.
The variety of climates, water depths, salinity, and landforms has produced a variety of flora and fauna, both in the sea and on its shores. More than 400 species of fish are found in the sea, along with shellfish, corals, sponges, and seaweeds. The western basin has a greater variety than the saltier eastern one. The total quantity, however, is not particularly large because of the relatively low level of phytoplankton production in the warm water.
Economy
From ancient times fishing has been an important economic activity in the Mediterranean basin, but catches were destined only for local markets. Tyrian purple dye, made from the Mediterranean rock whelk, was once an important product shipped from the coast of the Levant. Large quantities of sponges were also exported from Greece until rising costs, diminishing supplies, emigration of sponge fishermen, and synthetic substitutes almost obliterated the industry after World War II. Around the Mediterranean, agriculture has always been the basis of the economy. The principal crops are wheat and barley, but most important are specialty crops such as grapes, olives, citrus, and cork and the products made from them. Manufacturing is becoming increasingly important, especially in the European countries and in Israel. Evidence exists of petroleum and natural gas deposits in the deep sediments of the basin floors. Large gas deposits have been found in the Adriatic, and petroleum has been discovered off Malta, Spain, France, and Tunisia. Exploration is continuing, particularly off the coast of Israel and in the Aegean and Tyrrhenian seas.
Pollution
Concern has been expressed that the Mediterranean may be “dying” due to pollution, most of which comes from municipal and industrial wastes on the European shore. The problem is intensified by rapid industrialization and by increased use of the sea for the transport of petroleum and petroleum products. Pollutants have closed many beaches and hurt the tourist industry, which is economically important. International efforts to control pollution have begun.
History
The oldest civilizations along the Mediterranean were in Egypt (from 3000 BC), Crete and Greece (the Aegean civilization in the 2d millennium BC), and Anatolia (the Hittites during 1900-1200 BC). Subsequently, a number of maritime commercial states arose, including Phoenicia, Carthage, and the Greek city-states. Between the 3d century BC and the 1st century AD, Rome unified the entire basin under its rule. The Romans called the Mediterranean mare nostrum (Latin for “our sea”). After the Roman Empire dissolved in AD 476, Arabs swept across North Africa into Iberia, and Germans and Slavs invaded from the north. Between the 11th and the 14th centuries, several commercial city-states developed, particularly in Italy, including those of Genoa and Venice. The Ottoman Turks had established their empire throughout the eastern Mediterranean and in North Africa by the 16th century. Increasing piracy and the discovery of new sea routes to India around Africa led to a decline in the maritime importance of the Mediterranean.
During the 18th and 19th centuries the British dominated the sea. The opening of the Suez Canal in 1869 led to the sea’s recovery as a major trade route, and new ports developed. Britain’s dominance ended after World War II and was replaced by U.S. hegemony.
