The Red Sea is a sea inlet of the Indian Ocean, lying between Africa and Asia. Its connection to the ocean is in the south, through the Bab-el-Mandeb Strait and the Gulf of Aden. To the north of the Red Sea lies the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez, which leads to the Suez Canal. It is underlain by the Red Sea Rift, which is part of the Great Rift Valley.
The Red Sea has a surface area of roughly 438,000 km2 (169,000 sq mi), is about 2,250 km (1,400 mi) long, and 355 km (221 mi) across at its widest point. It has an average depth of 490 m (1,610 ft), and in the central Suakin Trough, it reaches its maximum depth of 2,730 m (8,960 ft).
The Red Sea is quite shallow, with approximately 40% of its area being less than 100 m (330 ft) deep, and approximately 25% being less than 50 m (160 ft) deep. The extensive shallow shelves are noted for their marine life and corals. More than 1,000 invertebrate species and 200 types of soft and hard coral live in the sea. The Red Sea is the world's northernmost tropical sea and has been designated a Global 200 ecoregion.
The International Hydrographic Organization defines the limits of the Red Sea as follows:On the North. The Southern limits of the Gulfs of Suez [A line running from Ràs Muhammed (27°43'N) to the South point of Shadwan Island (34°02'E) and thence Westward on a parallel (27°27'N) to the coast of Africa] and Aqaba [A line running from Ràs al Fasma Southwesterly to Requin Island (27°57′N 34°36′E) through Tiran Island to the Southwest point thereof and thence Westward on a parallel (27°54'N) to the coast of the Sinai Peninsula].
On the South. A line joining Husn Murad (12°40′N 43°30′E) and Ras Siyyan (12°29′N 43°20′E).
Exclusive economic zone
Exclusive economic zones in Red Sea:
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Reference material for this entry is drawn from the open encyclopedic record, including Wikipedia , available under the CC BY-SA 4.0 license. Images are credited individually beside each photo.
The English term Red Sea is a direct translation of the Ancient Greek Erythrà Thálassa (Ἐρυθρὰ Θάλασσα). The sea itself was once referred to as the Erythraean Sea by Europeans. As well as Mare Rubrum in Latin—alternatively, Sinus Arabicus (lit. 'Arabian Gulf')—the Romans called it Pontus Herculis (lit. 'Sea of Hercules'). Other designations include the Arabic البحر الأحمر (Al-Baḥr Al-Aḥmar; alternatively, بحر القلزم, Baḥr Al-Qulzum, 'the Sea of Clysma'); the Coptic ⲫⲓⲟⲙ ̀ⲛϣⲁⲣⲓ (Phiom ̀nšari); the Syriac ܝܡܐ ܣܘܡܩܐ (Yammāʾ summāqā); the Somali Badda Cas; and the Tigrinya ቀይሕ ባሕሪ (Qeyyiḥ bāḥrī). The name of the sea may signify the seasonal blooms of the red-coloured Trichodesmium erythraeum near the water's surface. A theory favored by some modern scholars is that the name red refers to the direction south, just as the Black Sea's name may refer to the north. The basis of this theory is that some Pre-Indo-European languages used color words to refer to the cardinal directions. Writing in the fifth century BCE, Herodotus uses the Red Sea and Southern Sea interchangeably.
The term Yam Suph (יַם־סוּף, 'Sea of Reeds') derives from the tale of God's parting of the Red Sea for the Israelites. Historically, it was also known to Western geographers as Mare Mecca ('Sea of Mecca') and Sinus Arabicus ('Arabian Gulf'). Some ancient geographers called the Red Sea the "Arabian Gulf" or the "Gulf of Arabia", too.
History
Ancient era
The earliest known exploration of the Red Sea was conducted by ancient Egyptians, as they attempted to establish commercial routes to Punt. One such expedition took place around 2500 BCE and another around 1500 BCE (by Hatshepsut). Both involved long voyages down the Red Sea.
The Hebrew Biblical Book of Exodus relates the account of the Israelites' crossing the Red Sea, which the Hebrew text calls Yam Suph (יַם־סוּף). Yam Suph was traditionally identified as the Red Sea. Rabbi Saadia Gaon (882‒942 CE), in his Judeo-Arabic translation of the Torah, identifies the crossing place of the Red Sea as Baḥar al-Qulzum, meaning the "Gulf of Suez".
In the 6th century BCE, Darius the Great, who was a prominent ruler of the Achaemenid Empire in Persia, undertook significant efforts to improve and extend navigation in the Red Sea. He sent reconnaissance missions to explore the Red Sea and identify its navigational hazards, such as rocks and currents. This effort was significant, as it contributed to safer and more efficient navigation routes.
In addition to the maritime explorations, during the reign of Darius the Great, a canal was constructed linking the Nile River to the northern end of the Red Sea at Suez. This canal is sometimes referred to as the ancient Suez Canal. It played a pivotal role in improving trade and communication between the Nile Valley and the Red Sea, and beyond to the Indian Ocean. This canal was a predecessor of the modern Suez Canal, which was constructed in the 19th century and remains one of the world's most important waterways.
Ancient records, including inscriptions, evidence the construction of the canal during Darius's reign. Darius commemorated the completion of the canal by creating stelae (stone monuments) with inscriptions in several languages, describing the construction and its benefits. The canal not only facilitated trade but also solidified Darius's control over Egypt and enhanced the Achaemenid Empire's economic and political power in the region.
In the late 4th century BCE, Alexander the Great sent Greek naval expeditions down the Red Sea to the Indian Ocean. Greek navigators continued to explore and compile data on the Red Sea. Agatharchides collected information about the sea in the 2nd century BCE. The Periplus of the Erythraean Sea (or Periplus of the Red Sea), a Greek periplus written by an unknown author around the 1st century, contains a detailed description of the Red Sea's ports and sea routes. The Periplus also describes how Hippalus first discovered the direct route from the Red Sea to.
The Red Sea was favored for Roman trade with India starting with the reign of Augustus, when the Roman Empire gained control over the Mediterranean, Egypt, and the northern Red Sea. The route had been used by previous states, but traffic volume increased under the Romans. From Indian ports, goods from China were introduced to the Roman world. Contact between Rome and China depended on the Red Sea, but the route was broken by the Aksumite Empire around the 3rd century CE.
From antiquity until the 20th century, the Red Sea was also a trade route for the Red Sea slave trade from Africa to the Middle East.
Middle Ages and modern era
During the Middle Ages, the Red Sea was an important part of the spice trade route. In 1183, Raynald of Châtillon launched a raid down the Red Sea to attack the Muslim pilgrim convoys to Mecca. The possibility that Raynald's fleet might sack the holy cities of Mecca and Medina caused fury throughout the Muslim world. However, it appears that Raynald's target was the lightly armed Muslim pilgrim convoys, rather than the well-guarded cities of Mecca and Medina, and the belief in the Muslim world that Raynald was seeking to sack the holy cities, due to the proximity of those cities to the areas that Raynald raided.
In 1513, trying to secure that channel to Portugal, Afonso de Albuquerque laid siege to Aden but was forced to retreat. They cruised the Red Sea through the Bab al-Mandab, as the first fleet from Europe in modern times to sail these waters. Later in 1524, the city was delivered to Governor Heitor da Silveira as an agreement for protection from the Ottoman Empire.
In 1798, France ordered General Napoleon I to invade Egypt and take control of the Red Sea. Although he failed in his mission, the engineer Jean-Baptiste Lepère, who took part in it, revitalised the plan for a canal which had been envisaged during the reign of the pharaohs. Several canals were built in ancient times from the Nile to the Red Sea along or near the line of the present Sweet Water Canal, but none lasted for long. The Suez Canal was opened in November 1869. During the first half of the 20th century, the Red Sea slave trade attracted substantial international condemnation.
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. Despite the 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 to piracy.
Red Sea crisis
Iranian-backed Yemeni Houthis have attacked Western ships, including warships, next to the Bab al-Mandeb during the Gaza war. One ship was hijacked and taken back to Yemen.
Oceanography
The Red Sea is between arid land, desert and semi-desert. Many regions of the coastal zone of the Red Sea possess large areas of vigorously growing coral and extensive reef complexes. Due to the tidal currents, low human population, and the minimal development in this climatically inhospitable region, the Red Sea coral reefs are some of the healthiest reef environments in the world. The Red Sea water mass-exchanges its water with the Arabian Sea and Indian Ocean via the Gulf of Aden. These physical factors reduce the effect of high salinity caused by evaporation in the north and relatively hot water in the south.
The climate of the Red Sea is the result of two monsoon seasons: a northeasterly monsoon and a southwesterly monsoon. Monsoon winds occur because of differential heating between the land and the sea. Very high surface temperatures and high salinity make this one of the warmest and saltiest bodies of seawater in the world. The average surface water temperature of the Red Sea during the summer is about 26 °C (79 °F) in the north and 30 °C (86 °F) in the south, with only about 2 °C (3.6 °F) variation during the winter months. The overall average water temperature is 22 °C (72 °F). Temperature and visibility remain good, with visibility around 200 m (660 ft). The sea is known for its strong winds and unpredictable local currents.
The rainfall over the Red Sea and its coasts is extremely low, averaging 60 mm (2.36 in) per year. The rain is mostly short showers, often with thunderstorms and occasionally with dust storms. The scarcity of rainfall and no major source of fresh water to the Red Sea result in excess evaporation as high as 2,050 mm (81 in) per year and high salinity with minimal seasonal variation. A recent underwater expedition to the Red Sea offshore from Sudan and Eritrea found surface water temperatures 28 °C (82 °F) in winter and up to 34 °C (93 °F) in the summer, but despite that extreme heat, the coral was healthy with much fish life with very little sign of coral bleaching, with only 9% infected by Thalassomonas loyana, the 'white plague' agent. Favia favus coral there harbours a virus, BA3, which kills T. loyana.
Scientists are investigating the unique properties of these corals and their commensal algae to determine whether they can be used to rescue bleached corals elsewhere.
Salinity
The Red Sea is one of the saltiest bodies of water in the world, owing to high evaporation and low precipitation; no significant rivers or streams drain into the sea, and its southern connection to the Gulf of Aden, an arm of the Indian Ocean, is narrow. Its salinity ranges from between ~36 ‰ in the southern part and 41 ‰ in the northern part around the Gulf of Suez, with an average of 40 ‰. (Average salinity for the world's seawater is ~35 ‰ on the Practical Salinity Scale, or PSU; that translates to 3.5% of actual dissolved salts).
Tidal range
In general, tide ranges between 0.6 m (2.0 ft) in the north, near the mouth of the Gulf of Suez and 0.9 m (3.0 ft) in the south near the Gulf of Aden, but it fluctuates between 0.20 m (0.66 ft) and 0.30 m (0.98 ft) 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 metres rather than flooding 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 (2 mi), whereas north of Jeddah in the Al-Kharrar area the sabkhas are covered by a thin sheet of water as far as 2 km (1.2 mi). The prevailing north- and northeast winds influence the movement of water from coastal inlets into adjacent sabkhas, especially during storms. Winter mean sea level is 0.5 m (1.6 ft) higher than in summer. Tidal velocities passing through constrictions caused by reefs, sand bars, and low islands commonly exceed 1–2 m/s (3–7 ft/s). Coral reefs in the Red Sea are near Egypt, Eritrea, Jordan, Israel, Saudi Arabia, and Sudan.
Current
Detailed information regarding current data is lacking, partially because the currents are weak and both spatially and temporally variable. The variation of temporal and spatial currents is as low as 0.5 m (1.6 ft) and is governed by the wind. During the summer, northwesterly winds drive surface water south for about four months at a velocity of 15–20 cm/s (6–8 in/s), 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, leading to an overall drift toward the north end of the Red Sea. Generally, the velocity of the tidal current is 50–60 cm/s (20–24 in/s) with a maximum of 1 m/s (3.3 ft/s) at the mouth of the al-Kharrar Lagoon. However, the range of the north-northeast current along the Saudi coast is 8–29 cm/s (3–11 in/s).
Wind regime
The northern part of the Red Sea is dominated by persistent north-west winds, with speeds ranging between 7 km/h (4.3 mph) and 12 km/h (7.5 mph). The rest of the Red Sea and the Gulf of Aden are subjected to regular and seasonally reversible winds. The wind regime is characterized by seasonal and regional variations in speed and direction with average speed generally increasing northward.
The wind is the driving force in the Red Sea, transporting material as suspended load or bedload. Wind-induced currents play an important role in the Red Sea by resuspending bottom sediments and transferring materials from dumping sites to burial sites in a quiescent depositional environment. Wind-generated current measurement is therefore important for determining sediment dispersal patterns and their role in the erosion and accretion of the coastal rock exposure and submerged coral beds.
Geology
The Red Sea was formed by the Arabian Peninsula being split from the Horn of Africa by the movement of the Red Sea Rift. This split started in the Eocene and accelerated during the Oligocene. The sea is still widening (in 2005, following a three weeks of tectonic activity it had grown by 8 m [26 ft]), and it is considered that it will become an ocean in time (as proposed in the model of John Tuzo Wilson). In 1949, a deep water survey reported anomalously hot brines in the central portion of the Red Sea. Later work in the 1960s confirmed the presence of hot, 60 °C (140 °F), saline brines and associated metalliferous muds. The hot solutions were emanating from an active subseafloor rift. Lake Asal in Djibouti is eligible as an experimental site to study the evolution of the deep hot brines of the Red Sea. By observing the strontium isotope composition of the Red Sea brines, it is possible to deduce how these salt waters found at the bottom of the Red Sea could have evolved in a similar way to Lake Asal, which ideally represents their compositional extreme. The high salinity of the waters was not hospitable to living organisms.
Sometime during the Tertiary, the Bab el Mandeb closed, and the Red Sea evaporated to an empty hot dry salt-floored sink. Effects causing this would have been:
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 Ice ages because of much water being locked up in the ice caps.
Several volcanic islands rise from the center of the sea. Most are dormant. However, in 2007, Jabal al-Tair island in the Bab el Mandeb strait erupted violently. Two new islands were formed in 2011 and 2013 in the Zubair Archipelago, a small chain of islands owned by Yemen. The first island, Sholan Island, emerged in an eruption in December 2011, and the second island, Jadid, emerged in September 2013. Approximately 40% of the Red Sea is quite shallow at less than 100 m (330 ft) deep, with about 25% less than 50 m (160 ft) deep.
Oil and gas
Undiscovered oil reserves in the region have been estimated at 801.5 million cubic metres (5,041 million barrels). Undiscovered gas reserves in the region have been estimated at 3,180 billion cubic metres (112,349 billion cubic feet). Undiscovered natural gas reserves have been estimated at 489 million cubic metres (3,077 million barrels). Most of these plays are controlled by the structure of the basin. Normal faults are common as the Red Sea occupies an active diverging margin. These targets are commonly found below the Salt deposits of the Middle Miocene.
Modern development is focused on the following fields. The Durwara 2 Field was discovered in 1963, while the Suakin 1 Field and the Bashayer 1A Field were discovered in 1976, on the Egyptian side of the Red Sea. The Barqan Field was discovered in 1969, and the Midyan Field in 1992, both within the Midyan Basin on the Saudi Arabian side of the Red Sea. The 20-m thick Middle Miocene Maqna Formation is an oil source rock in the basin. Oil seeps occur near the Farasan Islands, the Dahlak Archipelago, along the coast of Eritrea, and in the southeastern Red Sea along the coasts of Saudi Arabia and Yemen.
Mineral resources
In terms of mineral resources, the major constituents of the Red Sea sediments are as follows:
