Red Sea

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Red Sea,

ancient Sinus Arabicus or Erythraean Sea, narrow sea, c.170,000 sq mi (440,300 sq km), c.1,450 mi (2,330 km) long and up to 225 mi (362 km) wide, between Africa (Egypt, Sudan, and Eritrea) and the Arabian peninsula (Saudi Arabia and Yemen); a part of the Great Rift ValleyGreat Rift Valley,
geological fault system of SW Asia and E Africa. It extends c.3,000 mi (4,830 km) from N Syria to central Mozambique. The northernmost extension runs S through Syria and Lebanon, the Jordan valley, the Dead Sea, and the Gulf of Aqaba.
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. The Gulf of Aqaba and the Gulf of Suez are the sea's northern arms; between them is the Sinai peninsula. The Red Sea is linked with the Gulf of Aden and the Arabian Sea by the straits of Bab el MandebBab el Mandeb
[Arab.,= gate of tears], strait, 17 mi (27 km) wide, linking the Red Sea with the Gulf of Aden and separating the Arabian peninsula from E Africa. It is an important passage on the Indian Ocean–Mediterranean Sea shipping route via the Suez Canal.
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. The flat coastal plains of the Red Sea slope gradually to the submarine central trough, more than 7,000 ft (2,134 m) deep. The sea is dotted with islands (the largest group is the Dahlak ArchipelagoDahlak Archipelago
, island group, Eritrea, in the Red Sea off Massawa. There are two large, inhabited islands and more than 200 small, largely uninhabited islands. The islands are flat, barren, and mainly of coral origin.
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 in the southwest) and with dangerous coral reefs. It is surrounded by exceedingly hot and dry deserts and steppes; the summer water temperature exceeds 85°F; (29°C;), and the water has a high salt content. The Red Sea was an important trade route in antiquity. Its importance declined with the discovery of an all-water route around Africa in 1498. The opening of the Suez CanalSuez Canal,
Arab. Qanat as Suways, waterway of Egypt extending from Port Said to Port Tawfiq (near Suez) and connecting the Mediterranean Sea with the Gulf of Suez and thence with the Red Sea. The canal is somewhat more than 100 mi (160 km) long.
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 in 1869 made the Red Sea one of the chief shipping routes connecting Europe with East Asia and Australia. The closing of the canal after the 1967 Arab-Israeli War, the building of pipelines to the Mediterranean Sea, and the construction of supertankers too large for the canal diminished the sea's importance as a commercial artery, especially for petroleum. In 1975, however, the canal was reopened and enlarged, and traffic through the sea increased. Suez, Egypt; Elat, Israel; Jidda, Saudi Arabia; Hodeida, Yemen; Massawa, Eritrea; and Port Sudan, Sudan, are the main ports on the Red Sea and its northern arms.

Red Sea

 

(the name probably derived from the presence of large numbers of the algae Frishodesmium erythraeum, which become reddish in color at a certain period), an inland sea of the Indian Ocean, between the Arabian Peninsula and Africa. It washes the shores of the Arab Republic of Egypt, Sudan, Ethiopia, Saudi Arabia, and the Yemen Arab Republic. In the north the Suez Canal connects it with the Mediterranean Sea; in the south the Strait of Bab el-Mandeb connects it with the Gulf of Aden and the Arabian Sea. Length, 1,932 km; maximum width, 305 km; area, 450,000 sq km; water volume, 251,000 cu km.

The shores of the Red Sea do not have many indentations; their outline was basically determined by fault tectonics and for virtually their entire length the eastern and western coasts parallel each other. In the northern part of the sea are the Gulf of Suez and the Gulf of Aqaba, which are divided by the Sinai Peninsula. There are few islands in the north, but south of 17°N lat. they form numerous groups. The largest group is the Dahlak Archipelago in the southwestern part of the sea.

In the relief of the sea floor the outstanding features are the coastal shoal (up to 200 m deep), which is broadest in the southern part of the sea and has numerous coral and native islands; the main trough, a narrow basin that occupies the greater part of the sea floor and has an average depth of 1,000 m; and the axial trough, a narrow, deep trench that seems to cut into the main trough and has a maximum depth of 2,811 m.

In a geotectonic sense the basin of the Red Sea (main trough) is a rift, genetically related to the system of rifts of the Gulf of Aden and the rift valleys of East Africa. Further to the north this system continues in the rifts of the Gulf of Aqaba, the Jordan valley, and the basin of the Dead Sea.

Beneath most of the sea floor there is a “granitic” crystalline basement overlain by a layer of limestones and evaporites from 1 to 2–4 km thick. Loose or weakly consolidated sediments, primarily of carbonate, are found on top of this layer. The granites are not present under the axial trough, and there the bottom is composed of basic rock, while the sedimentary layer is cemented by iron oxides and oxides of nonferrous metals (Zn, Cu, and Pb) that separated out from deep-lying brine whose points of discharge were recently discovered in several basins of the axial trough. The temperature of these springs reaches 62°C and salinity is up to 280 parts per thousand (‰). It appears that the discharge of these hot and heavily salt-saturated waters is connected to abyssal fractures that are expressed in the relief in the form of the axial trough.

The climate is a monsoon climate, but it is distinguished by great dryness because of the sea’s position between the deserts of the Arabian Peninsula and North Africa. Between October and April, north of 20°N lat. north-northwest winds prevail, which give way south of this to south-southeast winds. Between May and September north-northwest winds prevail over the entire area of the sea. The mean January temperature ranges from 15.5°C in the north to 27°C in the south; the mean temperature for August ranges from 27°C in the north to 32°C in the south. Precipitation falls primarily in the winter (from 28 mm in the north to 217 mm in the south). Dust clouds and mirages are characteristic of the Red Sea.

The surface currents are seasonal in nature. In the southern part of the sea between November and March the current moves north-northwest along the shore of the Arabian Peninsula at a velocity of 2 km per hr. Between June and September a south-southeast current prevails. Along the eastern shore of the northern part of the sea a north-northwest countercurrent (velocity of about 2 km per hr) is observed; it compensates for waters moving south. In May, April, and October, transition currents from winter to summer currents, and vice versa, are observed. The mean water temperature on the surface in February ranges from 18°C in the north to 26.5°C in the south; the corresponding figures for August are 27°C and 32°C. The small inflow of fresh water and intensive evaporation from the surface of the sea (a layer of water measuring 3.5 m a year) cause a great increase in its salinity, which is more than 41.5‰ (the greatest of any sea on earth) near the Gulf of Suez and the Gulf of Aqaba, 40.5-41.0‰in the northern part of the sea, and 38.0—39.0‰ in the south. The water density is 1,028 in the north and 1,024 in the south. Tides are primarily semidiurnal: in Suez Bay their magnitude is 1.6 m, and in the open part of the sea it is 0.6 m. Transparency is about 50 m. The color of the water is mainly bluish green, but near the reefs the water sometimes takes on a milky tint as a result of the large number of suspended particles of coral sand.

Bottom waters form in the northern part during the period of winter cooling, when intensive vertical circulation develops (the temperature of bottom waters is up to 21.7°C and salinity is 40.5-42.3‰). The saline bottom waters of the Red Sea pass into the ocean through the Strait of Bab el-Mandeb and begin the formation of the ocean’s bottom waters. On the average the discharge of Red Sea bottom waters into the Indian Ocean is 300,000-400,000 cu m per sec. A surface current enters the Red Sea from the Gulf of Aden at an average velocity of 3.7-4.6 km per hr. The influx of water from the Gulf of Aden to the Red Sea averages about 500,000 cu m per sec. Water exchange through the Suez Canal is insignificant.

The sea is qualitatively poor in plants but quite rich and varied in animal life (dolphins, dugongs, giant sea turtles, and more than 400 species of fish).

The Red Sea is very important for maritime traffic between the countries of Africa, Europe, Asia, and Australia. The principal ports are Suez (Arab Republic of Egypt), Port Sudan (Sudan), Jiddah (Saudi Arabia), Massaua (Ethiopia), and Al-Hudaydah (Yemen Arab Republic).

A. M. MUROMTSEV

Red Sea

[′red ′sē]
(geography)
A body of water that lies between Arabia and northeastern Africa, about 1200 miles (2000 kilometers) long, 180 miles (300 kilometers) wide, and a maximum depth of about 7600 feet (2300 meters).

Red Sea

a long narrow sea between Arabia and NE Africa, linked with the Mediterranean in the north by the Suez Canal and with the Indian Ocean in the south: occasionally reddish in appearance through algae. Area: 438 000 sq. km (169 000 sq. miles)