Red Sea

2007 Schools Wikipedia Selection. Related subjects: General Geography

Location of the Red Sea
Location of the Red Sea

The Red Sea is an inlet of the Indian Ocean between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb sound and the Gulf of Aden. In the north are the Sinai Peninsula, the Gulf of Aqaba or the Gulf of Eilat and the Gulf of Suez (leading to the Suez Canal).

Occupying a part of the Great Rift Valley, the Red Sea has a surface area of roughly 174,000 square miles (450,000 km²): being roughly 1,200 miles (1,900 km) long and, at its widest point, over 190 miles (300 km) wide. It has a maximum depth of 8,200 feet (2,500 m) in the central median trench and an average depth of 1,640 feet (500 m), but there are also extensive shallow shelves, noted for their marine life and corals. The sea is the habitat of over 1,000 invertebrate species and 200 soft and hard corals and is the world's most northern tropical sea.

The Red Sea is regarded as one of the most saline water bodies in the world that is governed by the effects of the water circulation pattern, resulting from evaporation and wind stress in the Red Sea. Salinity ranges between 36 and 38 ‰.


Red Sea is a direct translation of the Latin Mare Erythraeum, Arabic Al-Baḥr Al-Aḥmar (البحر الأحمر), and Tigrinya Qeyḥ bāḥrī (ቀይሕ ባሕሪ).

The name of the sea does not indicate the color of the water, because it is not red in colour. It may signify the seasonal blooms of the red-colored cyanobacteria Trichodesmium erythraeum near the water surface. Some suggest that it refers to the mineral-rich red mountains nearby which are called Harei Edom (הרי אדום). Edom, meaning "ruddy complexion", is also an alternative Hebrew name for the red-faced biblical character Esau (brother of Jacob), and the nation descended from him, the Edomites, which in turn provides yet another possible origin for Red Sea.

There is also speculation that the name Red Sea came from a mistranslation of what should have been Reed Sea in the Biblical account of the Exodus.

Another hypothesis is that the name comes from the Himarites, a local group whose own name means red.

Yet another theory favored by some modern scholars is the name red is referring to the direction south, the same way the Black Sea's name may refer to north. The basis of this theory is that some Asiatic languages used colour words to refer to the cardinal directions.

A final theory suggests that it was named so because because it borders the Egyptian Desert which the ancient Egyptians called the Dashret or "red land"; therefore it would have been the sea of the red land.


The Egyptians were the first to attempt a mission of exploration in the Red Sea. In the Bible, the story of The Exodus tells how Moses, the son of a slave woman, leads the Israelites across its headwaters, (presumably the Reed Sea which has since disappeared because of the Suez Canal water diversion) to freedom, by using the powers of God to part the waters. However, it was a Greek sailor, Hippalus, who conferred an international dimension upon the Red Sea in his manifesto on the voyage of the Eritrea Sea and thus opened it up to an immense and exclusive trade with Asia. It was only from the 15th century onwards that Europe began to show interest in this area. In 1798, France charged General Bonaparte with invading Egypt and capturing the Red Sea. Although he failed in his mission, the engineer J.B. Lepere, who took part in it revitalised the plan for a canal which had been envisaged during the reign of the Pharaohs. The Suez Canal was opened in November 1869. At the time, the British, French, and Italians shared the trading posts. The posts were gradually dismantled following the First World War. After the Second World War, the Americans and Soviets exerted their influence whilst the volume of oil tanker traffic intensified. However, the Six Day War culminated in the closure of the Suez Canal from 1967 to 1975. Still today, in spite of patrols by the major maritime fleets in the waters of the Red Sea, the Suez Canal has never recovered its supremacy over the Cape route, which is believed to be less vulnerable.


The Red Sea lies between arid land, desert and semi-desert. The main reasons for the better development of reef systems along the Red Sea is because of its greater depths and an efficient water circulation pattern, The Red Sea water mass exchanges its water with the Arabian Sea, Indian Ocean via the Gulf of Aden. These physical factors reduce the effect of high salinity caused by evaporation and cold water in the north and relatively hot water in the south.

Climate: The climate of the Red Sea is the result of two distinct monsoon seasons; a northeasterly monsoon and a southwesterly monsoon. Monsoon winds occur because of the differential heating between the land surface and sea. Very high surface temperatures coupled with high salinities makes this one of the hottest and saltiest bodies of seawater in the world. The average surface water temperature of the Red Sea during the summer is about 26°C in the north and 30°C in the south, with only about 2°C variation during the winter months. The overall average water temperature is 22°C. The rainfall over the Red Sea and its coasts is extremely low averaging 0.06 m per year; the rain is mostly in the form of showers of short spells often associated with thunderstorms and occasionally with dust storms. The scarcity of rainfall and no major source of fresh water to the Red Sea result in the excess evaporation as high as 205 cm per yr and high salinity with minimal seasonal variation.

Salinity: The Red Sea is regarded as one of the most saline water bodies in the world that is governed by the effects of the water circulation pattern, resulting from evaporation and wind stress in the Red Sea. Salinity ranges between 36 and 38 ‰.

Tidal range: In general tide ranges between 0.6 m in the north, near the mouth of the Gulf of Suez and 0.9 m in the south near the Gulf of Aden but it fluctuates between 0.20 and 0.30 m away from the nodal point. The central Red Sea (Jeddah area) is therefore almost tideless, and as such the annual water level changes are more significant. Because of the small tidal range the water during high tide inundates the coastal sabkhas as a thin sheet of water up to a few hundred meters rather than inundating the sabkhas through a network of channels. However, south of Jeddah in the Shoiaba area the water from the lagoon may cover the adjoining sabkhas as far as 3 km whereas, north of Jeddah in the Al-kharrar area the sabkhas are covered by a thin sheet of water as far as 2 km. The prevailing north and northeastern winds influence the movement of water in the coastal inlets to the adjacent sabkhas, especially during storms. Winter mean sea level is 0.5 m higher than in summer. Tidal velocities passing through constrictions caused by reefs, sand bars and low islands commonly exceed 1-2 m per sec.

Current: In the Red Sea detailed current data is lacking, partially because they are weak and variable both spatially and temporally. Temporal and spatial currents variation is as low as 0.5 m and are governed mostly by wind. In summer NW winds drive surface water south for about four months at a velocity of 15-20 cm per sec., whereas in winter the flow is reversed resulting in the inflow of water from the Gulf of Aden into the Red Sea. The net value of the latter predominates, resulting in an overall drift to the northern end of the Red Sea. Generally the velocity of the tidal current is between 50-60 cm per sec with a maximum of 1 m per sec. at the mouth of the al-Kharrar Lagoon. However, the range of north-northeast current along the Saudi coast is 8-29 cm per sec.

Wind Regime: With the exception of the northern part of the Red Sea, which is dominated by persistent north-west winds, with speeds ranging between 7 and 12 km per hr., the rest of the Red Sea and the Gulf of Aden are subjected to the influence of regular and seasonally reversible winds. The wind regime is characterized by both seasonal and regional variations in speed and direction with average speed generally increasing northward.

Wind is the driving force in the Red Sea for transporting the material either as suspension or as bedload. Wind induced currents play an important role in the Red Sea in initiating the process of resuspension of bottom sediments and transfer of materials from sites of dumping to sites of burial in quiescent environment of deposition. Wind generated current measurement is therefore important in order to determine the sediment dispersal pattern and its role in the erosion and accretion of the coastal rock exposure and the submerged coral beds.


Dust storm over the Red Sea
Dust storm over the Red Sea

The Red Sea formed by Arabia splitting from Africa due to continental drift. This split started in the Eocene and accelerated during the Oligocene. The sea is still widening and it is considered that the sea will become an ocean in time (as proposed in the model of Tuzo Wilson).

Sometimes during the Tertiary period the Bab el Mandeb closed and the Red Sea evaporated to an empty hot dry salt-floored sink. Effects causing this would be:-

  • A "race" between the Red Sea widening and Perim Island erupting filling the Bab el Mandeb with lava.
  • The lowering of world sea level during the Ice Ages due to much water being locked up in the ice caps.

Today surface water temperatures remain relatively constant at 70–77 °F (21–25 °C) and temperature and visibility remain good to around 660 feet (200 m), but the sea is known for its strong winds and tricky local currents.

In terms of salinity, the Red Sea is greater than the world average, approximately 4 percent. This is due to several factors: 1) high rate of evaporation and very little precipitation, 2) a lack of significant rivers or streams draining into the sea, and 3) limited connection with the Indian Ocean (and its lower water salinity).

Desalination Plants

The Red Sea water is an essential asset. There is extensive demand of desalinated water to meet the requirement of the population and the industries along the Red Sea.

There are at least 18 desalination plants along the Red Sea coast of Saudi Arabia which discharge warm brine and treatment chemicals(chlorine and anti-scalants) that may cause bleaching and mortality of corals and diseases to the fish stocks. Although this is only a localized phenomenon, it may intensify with time and have a profound impact on the fishing industry.

The water from the Red Sea is also utilized by oil refineries and cement factories for cooling purposes. Used water drained back into the coastal zones may cause harm to the nearshore environment of the Red Sea.

Facts and Figures at a Glance

  • Length: ~1900 km - 79 % of the eastern Red Sea with numerous coastal inlets
  • Maximum Width: ~ 306 – 354 km – Massawa (Eritrea)
  • Minimum Width: ~ 26 – 29 km -Strait Bab al Mandeb (Yemen)
  • Average Width: ~ 280 km
  • Average Depth: ~ 490 m
  • Maximum Depth: ~2850 m
  • Total surface Area: 438 x 103- 450 x 103 km²
  • Volume: 215 x 103 –251 x 103 km³
  • Approximately 40 % of the Red Sea is quite shallow (under 100 m) whereas about 25 % of the Red Sea is under 50 m deep. About 15 % of the Red Sea is over 1000 m depth that forms the deep axial trough.
  • Shelf breaks are marked by coral reefs
  • Continental slope has an irregular profile (series of steps down to ~500 m)
  • Centre of Red Sea has a narrow trough (~ 1000 m; some deeps may exceed 2500 m)

Some of the Research cruises in the Red Sea

Numerous research cruises have been conducted

  • Arabia Felix (1761-1767)
  • Vitiaz (1886-1889)
  • Valdivia (1898-1894)
  • Pola (1897-98) Southern Red Sea and (1895/96 – Northern Red Sea
  • Ammiraglio Magnaghi (1923/24)
  • Snellius (1929 –1930)
  • Mabahiss (1933-1934 and 1934-1935)
  • Albatross (1948)
  • Manihine (1849 and 1952)
  • Calypso (1955)
  • Atlantis and Vema (1958)
  • Xarifa (1961)
  • Meteor (1961)
  • Glomar Challenger (1971)
  • Sonne 1997
  • Meteor 1999


The sea is known for its spectacular dive sites such as Ras Mohammed, SS Thistlegorm (ship wreck), Elphinstone, The Brothers and Rocky Island in Egypt, Dolphin Reef in Eilat Israel and less known sites in Sudan such as Sanganeb, Abington, Angarosh and Shaab Rumi (see photo above).

The Red Sea was "discovered" as a diving destination by Hans Hass in the 1950s, and by Jacques-Yves Cousteau later. Popular tourist resorts include Sharm-El-Sheikh and Hurghada (and recently Marsa Alam) in Egypt, as well as Eilat, Israel in an area known as the Red Sea Riviera.

Bordering countries

Bordering countries are:

Towns and cities

Towns and cities on the Red Sea coast include:

  • Aqaba العقبة ,
  • Arkiko ሕርጊጎ,
  • Assab ዓሳብ,
  • Dahabدهب ,
  • Eilat אילת ,
  • Hala'ib حلايب ,
  • Al Hudaydah الحديدة,
  • Hurghada الغردقة,
  • Jeddahجدة ,
  • Marsa Alamمرسى علم ,
  • Massawa ምጽዋ,
  • Nuweiba نويبع ,
  • Port Safaga ميناء سفاجا ,
  • Port Sudan بورت سودان ,
  • Sharm el Sheikh شرم الشيخ ,
  • Suakin سواكن,
  • El Suweis السويس ,
  • Taba الطور,
  • El-Tor الطور
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