Mediterranean << `mehd` uh tuh RAY nee uhn >> Sea has been one of the world’s chief trade routes since ancient times. Many early civilizations, including those of Egypt, Greece, Phoenicia, and Rome, developed along its shores. Today, the islands and coastal areas of the Mediterranean rank among the most popular tourist attractions in the world.
Location and size.
The Latin word mediterranean means in the middle of land, and land almost surrounds the Mediterranean Sea. Europe lies to the north, Asia to the east, and Africa to the south.
On the west, the Strait of Gibraltar connects the Mediterranean with the Atlantic Ocean. Another strait, the Dardanelles, links the Mediterranean on the east with the Sea of Marmara, the Bosporus, and the Black Sea. On the southeast, the Isthmus of Suez separates the Mediterranean and Red seas. The Suez Canal, an artificial waterway, crosses this thin strip of land.
The Mediterranean covers about 969,100 square miles (2,510,000 square kilometers). The Black Sea, which many people consider part of the Mediterranean, has an area of about 173,000 square miles (448,000 square kilometers). Several other arms of the Mediterranean are large enough to be called seas. They include the Adriatic, Aegean, Ionian, and Tyrrhenian seas.
Excluding the Black Sea, the Mediterranean is more than twice as long as it is wide. It has a maximum length of about 2,200 miles (3,540 kilometers), between the Strait of Gibraltar and Iskenderun, Turkey. The widest part of the sea lies between Libya and Croatia, a distance of about 1,000 miles (1,600 kilometers).
The seabed.
An underwater ridge between Sicily and Tunisia divides the Mediterranean into two basins. The eastern basin is deeper than the western one. The sea has an average depth of 4,926 feet (1,501 meters). It reaches its greatest depth—16,302 feet (5,093 meters)—in a depression called the Hellenic Trough that lies between Greece and Italy.
Earthquakes occur frequently throughout the Mediterranean region, especially in Greece and western Turkey. Volcanic action formed many of the islands in the Mediterranean Sea. A few volcanoes still erupt in the area. They include Mount Etna, Stromboli, and Vesuvius.
Earth scientists explain the earthquakes and volcanic activity by the theory of plate tectonics. According to this theory, Earth’s outer shell consists of about 30 rigid plates that are in slow, continuous motion. Movements of plates that carry the European and African continents and the Mediterranean seabed squeeze and stretch Earth’s crust in the Mediterranean region, causing earthquakes and volcanoes.
Coastline and islands.
Many bays and inlets indent the coastline of the Mediterranean. Several large peninsulas, including Italy and the Balkan Peninsula, jut out into the sea. Along most of the coast, rugged hills rise sharply from the water. Egypt and Libya have flatter coastal areas, with plains lying next to the sea.
Sicily, the largest island in the Mediterranean, covers 9,926 square miles (25,708 square kilometers). Other large islands include, in order of size, Sardinia, Cyprus, Corsica, and Crete.
Climate.
The temperature at the surface of the Mediterranean averages about 61 °F (16 °C). In summer, the temperature may reach 80 °F (27 °C). It seldom drops below 40 °F (4 °C). The water varies little in temperature in the middle depths and near the bottom. It stays between 54° and 59 °F (12° and 15 °C) throughout the year.
The tremendous volume of warm water helps give the land surrounding it a warm, subtropical climate. Most Mediterranean countries have hot, dry summers and mild, rainy winters. These conditions provide what has become known as a “Mediterranean climate,” even when they occur elsewhere. Two Mediterranean countries, Egypt and Libya, have tropical climates, hotter and dryer than the typical Mediterranean type.
A hot wind known as the sirocco blows across the Mediterranean from Africa toward southern Europe. A cold, dry wind called the mistral blows the other way, from France out over the sea. See Sirocco.
The water
of the Mediterranean comes mostly from the Atlantic Ocean and the Black Sea and from rainfall. Several large rivers also empty into the Mediterranean. The largest include the Ebro of Spain, the Nile of Egypt, the Po of Italy, and the Rhone of France. The Nile has contributed less water since 1964, when the Aswan High Dam in Egypt began partly blocking its flow.
The warm, dry climate gives the sea a high rate of evaporation. As a result, the water of the Mediterranean is saltier than that of the Atlantic.
Most parts of the Mediterranean have a semidiurnal tide—that is, it has two high tides and two low tides about every 24 hours. But the average difference between a high tide and a low tide in the Mediterranean is only about 1 foot (0.3 meters). A strong current flows into the Mediterranean from the Black Sea. Another flows in from the Atlantic through the Strait of Gibraltar. Beneath the surface current, a deeper current of dense salty water flows from the Mediterranean to the Atlantic.
Economic importance.
The warm climate, beautiful scenery, and historical importance of the Mediterranean region attract millions of tourists yearly. Popular resort areas include the Greek islands and the French, Italian, and Spanish rivieras. In recent times, many immigrants have crossed to the northern side of the sea, moving from such countries as Morocco, Algeria, and Turkey toward the promise of better economic opportunities in Europe.
The Mediterranean has little large-scale commercial fishing, but it is an important source of food for the people of the region. The chief seafoods include anchovies, sardines, shrimp, and tuna. Other products harvested from the sea include coral and sponges. The Mediterranean serves as an important waterway that links Europe, the Middle East, and Asia. Ships use the Suez Canal as a route between the Mediterranean and Red seas. Deposits of petroleum and natural gas have been discovered in the seabed beneath the Mediterranean. But most of these resources remain unused.
Formation
of the Mediterranean Sea can be explained by the theory of plate tectonics. About 250 million years ago, the continents formed a single land mass called Pangaea. The Tethys Sea, a huge bay that developed into the Mediterranean, indented the east coast of Pangaea. Through the centuries, Pangaea broke up into continents that began to drift slowly toward their present location. As they drifted, Africa turned counterclockwise, and Eurasia turned clockwise. Their movement opened a waterway at the western end of the sea, linking it with the ocean. By about 65 million years ago, the rotation of these two continents had almost closed the eastern end of the Tethys Sea. The sea thus acquired its present shape.
Earth scientists believe that the Mediterranean dried up multiple times between about 6 million and 5.3 million years ago. During this period, the movement of the European and African continents repeatedly closed and reopened the Strait of Gibraltar. Each time the strait closed, the Mediterranean began to dry up. Also, glaciers may have lowered the Atlantic Ocean’s water level, helping to prevent Atlantic water from passing through the strait to the Mediterranean. Eventually, only a large desert remained. A few salty lakes dotted this desert. When the strait reopened, water from the Atlantic rushed in, refilling the Mediterranean.
In 1970, scientists found evidence that supported the desert theory. That year, geologists aboard a research vessel called the Glomar Challenger drilled cores of rock from the Mediterranean floor. The cores contained deposits of salt and other minerals, known as evaporites, that are formed by the evaporation of salty water. However, some researchers now believe the deposits could have resulted from a drastic lowering of the Mediterranean’s water level without it completely drying up.
History of the Mediterranean.
Many historians believe Western civilization was born in the Mediterranean region. Ancient cultures grew up on the banks of the sea, where conditions favored their development. The mild climate encouraged human settlement. The sea’s calm waters and steady winds most of the year made seafaring relatively easy. The sea also had natural harbors and many islands that sailors could use as ports.
Probably the first great civilization to develop in the Mediterranean region was that of ancient Egypt. The Egyptians had a unified national government by about 3100 B.C. and had begun using a writing system by 3000 B.C. The first important European civilization, the Minoan culture, arose on the island of Crete about 3000 B.C. Another culture, the Helladic civilization, grew up on the Greek mainland. One city, Mycenae, became so powerful that some historians call the later Helladic civilization Mycenaean. By about 1450 B.C., Mycenaean ships controlled the Mediterranean. They traded with cities as far away as what are now Lebanon and Syria.
After about 1200 B.C., the Phoenicians began to win control of the Mediterranean. From their homes on the eastern shore, they sailed to all parts of the sea. Phoenician sailors even traveled through the Strait of Gibraltar into the Atlantic. Carthage, a colony founded by the Phoenicians, became another great sea power after about 600 B.C. By the A.D. 100’s, the Roman Empire ruled all the lands that bordered the sea. The Romans called the Mediterranean Mare Nostrum (Our Sea).
For centuries, the Mediterranean was the world’s greatest water route. From the 1100’s to the 1500’s, a series of Crusades brought thousands of Western European Christians across the Mediterranean to fight Muslims for control of Palestine (see Crusades). During this time, trading centers such as Barcelona, Constantinople, Genoa, and Venice expanded, linking Europe and Asia. The ships of these cities brought goods from India and China across the sea to Europe. The Portuguese explorer Vasco da Gama sailed around Africa in 1497, reaching India in 1498. Trading ships then began to use this easier, all-water route to the East. Thus, the sea’s importance as a trade route declined until the 1800’s.
The opening of the Suez Canal in 1869 made the Mediterranean a part of the shortest water route between Europe and Asia. The sea was one of the world’s busiest shipping lanes until 1967, when the Suez Canal was closed during the Arab-Israeli war. It reopened in 1975.
Pollution of the Mediterranean became a serious problem. The major sources of pollution were oil, sewage, agricultural fertilizers and pesticides, and industrial pollutants, including tar, plastic bags, and waste from ships and planes. Most of the pollutants came from coastal settlements or were carried from inland sources by rivers. The pollution posed a threat to sea life. The polluted water also threatened people by spreading typhoid, infectious hepatitis, and other diseases.
In 1976, the United Nations Environment Programme (UNEP) sponsored a treaty called the Convention for the Protection of the Mediterranean Sea Against Pollution. The convention is also known as the Barcelona Convention for the city in Spain where it was signed. All the nations that border the Mediterranean have ratified the treaty. UNEP conducts programs to develop plans to stop Mediterranean pollution and to study the trends of pollution in the sea.
