intercontinental sea situated between Europe to the north, Africa to the
south, and Asia to the east. It covers an area, including the Sea of Marmara
but excluding the Black Sea, of about 970,000 square miles (2,512,000
To the west the Mediterranean Sea is connected
to the Atlantic Ocean by the Strait of Gibraltar, which
at its narrowest point is only 8 miles (13 km) wide and has a relatively
shallow channel. To the northeast the Dardanelles, the Sea
of Marmara, and the strait of the Bosporus link
the Mediterranean Sea to the Black Sea. The Suez Canal connects
it with the Red Sea to the southeast. The Mediterranean's greatest recorded
depth is in the Ionian Basin south of Greece at 16,800 feet (5,121 m)
below sea level.
A submarine ridge between the island of Sicily
and the African coast divides the Mediterranean Sea into eastern and western
parts. The western Mediterranean has three submarine basins separated
from each other by submerged ridges, including from west to east, the
Alborán, the Algerian, and the Tyrrhenian basins. The Ionian Basin
(northwest of which is the Adriatic Sea) and the Levantine Basin (northwest
of which is the Aegean Sea) compose the eastern part of the Mediterranean
Sea. Majorca, Corsica, Sardinia, Sicily, Crete, Cyprus, and Rhodes are
the largest islands in the Mediterranean.
The Mediterranean once was thought to be
a remnant of the Tethys Sea, which formerly girdled the Eastern Hemisphere;
it is now known to be a structurally younger basin. The sea's continental
shelves are relatively narrow. The widest shelf, off the Gulf of Gabes
(Qabis) on the eastern coast of Tunisia, extends 170 miles (275 km); the
bed of the Adriatic Sea is also mostly continental shelf. The floor of
the Mediterranean consists of sediments made up of lime, clay, and sand,
under which is blue mud. The sea's coasts are generally steep, rocky,
and deeply indented. The Rhône, Po, and Nile rivers have formed
the only large deltas in the Mediterranean Sea. The continuous inflow
of surface water from the Atlantic Ocean is the sea's major source of
replenishment. The most constant component of circulation in the Mediterranean
Sea is the current formed by this inflow from the Strait of Gibraltar
along the north coast of Africa. The whole Mediterranean basin is tectonically
active, and earthquakes are common.
The climate is characterized by mild, wet
winters and hot, dry summers. The air flow into the Mediterranean is through
gaps in the mountain ranges, except over its southern shores east of Tunisia.
Much of North Africa rarely receives more than 10 inches (250 mm) of rainfall
annually, whereas on the rugged Dalmatian coast of Croatia, some areas
receive 100 inches (2,500 mm).
The low concentration of phosphates and nitrates,
necessary for marine pastures, limits the quantity of marine life in the
Mediterranean. Small-scale fishing operations predominate, with the most
important species including hake, flounder, sole, turbot, sardine, anchovy,
bluefin tuna, bonito, and mackerel; shellfish, corals, sponges, and seaweed
are also harvested. Overexploitation of the sea's marine resources remains
a serious problem.
Petroleum deposits have been found off Spain,
Sicily, Libya, and Tunisia, and natural gas has been discovered in the
Adriatic Sea. Specialty crops of the region include olives, citrus fruits,
grapes, and cork. Tourism is a major source of income for many of the
countries bordering the Mediterranean.