Curiosities about the Red Sea

| No TrackBacks
by Marine Biologist, Daniele Zanoni

Ever wondered what makes the Red Sea red? Where the name comes from? Its history, attraction and marine life?

Read on as respected marine biologist, Daniele Zanoni (pic left) shares his fascinating knowledge on all things Red Sea...


Max width:
Max Depth:
Average depth:
438,000 km2
2250 km
355 km
2211 m
490 m
215-251 x 108 km3

The Red Sea is the northern most tropical sea. It hosts over 1000 invertebrate species, about 200 species of hard and soft coral and over 1200 species of fish and other vertebrates. The International Hydrographic Organization defined the Red Sea boundaries as follows:

  • North boundary: the southern limits of the Gulf of Suez and the Gulf of Aqaba
  • South boundary: a line joining Husn Murad and Ras Siyan
The name originated from the Greek (Erythra Thalassa) and Latin languages (Mare Rubrum), and later from Arabic (Al Bahr Al Ahmar). There are many theories about why it is called Red Sea.

Theory 1
The seasonal bloom of a filamentous cianobacterium, called sea sawdust (Trichodesmium erythraeum), creates red patches near the surface and so the sea looks sort of red during some periods of the year.

Theory 2
In traditional Chinese astronomy the zodiacal belt is divided in to four constellations, each of them corresponding to a cardinal direction. Each direction is identified by a colour and a mythological creature of that colour. All these traditions followed the migration of the Turkish people westward and hence came into use in other parts of the world:

  • East is green (Spring): Quingdao meaning green island is a city on the East coast of China
  • South is red (Summer): Red River in the South of China and Red Sea in the South of Turkey
  • West is white (Autumn): White Sea in Turkish indicates the Sea of Marmara (also called the Aegean Sea or Mediterranean Sea) which is west from Turkey. Belarus (literally meaning White Russia) is the name given to the Western Rus by the Mongols
  • North is black (Winter): Heilongjiang (Black Dragon River) is a province in Northern China; Black Sea is a sea North of Turkey
  • Centre is yellow: this point was identified as the centre of the four directions, namely earth. Mount Huang (Yellow Mountain) is in the centre of China
Herodotus used Red Sea and Southern Sea interchangeably.

Theory 3
In 110 BC there was a state in ancient Yemen called Homerite Kingdom, nowadays the city of Sanaa. The people living in this state were called Himyarites meaning of course "red".

Theory 4
The Red Sea borders the Egyptian Desert, which in ancient Egyptian was called Dashret meaning "Red Land". Therefore it would be the Sea of the Red Land.

There are more than these four theories, but these are the most credited ones.


The Red Sea is the second saltiest sea of the world. Its salinity ranges from 36% in the South to 41% in the North. The high salinity is mainly due to strong evaporation (up to 205 cm a year) and to the water coming from the Gulf of Suez. In addition precipitations are scarce; there is no run off or estuaries and the connection with the less salty Indian Ocean is limited. The average salinity of the world's sea water is around 35%. An average person weighing 70 Kg will need around 2 Kg extra lead to dive in the Red Sea giving they are using the same equipment.
The average tidal range is about 1.1 m varying from area to area. Tidal velocities passing through constrictions caused by reefs, sand bars and low islands may exceed 1-2 m/s (2-4 kt). The prevailing winter north and northeastern winds influence the water movement in coastal inlets raising the water level about 0.5 m during this period.


The Red Sea was formed during the Eocene (56 to 34 million years ago). Arabia split from Africa driven by the Red Sea Rift, a process that accelerated in the Oligocene (34 to 23 million years ago). The Red Sea is still widening at a rate of 1.17 cm per year and, according to some models, it is supposed to become an ocean in time. Around 20 million years ago, the Arab Peninsula started to move to the north. This movement did not find an easy way northward because of the resistance of Turkey, so the peninsula started to move toward east forming another break line. This line stretches all the way from Israel through the Jordan valley to the Dead Sea and finally to the Gulf of Eilat to Ras Mohammed at the south part of Sinai. The young age of the Gulf of Eilat makes it very deep (1800 m north from the Straits of Tiran). During the Tertiary period (65 to 1.8 million years ago) it happened sometimes that Bab El Mandeb (the strait between Yemen and Djibouti) closed and the Red Sea evaporated forming a hot dry salty floor. The effects causing this are not known for sure, but the best speculations are:

  • Perim Island could have erupted and filled the strait with lava, inhibiting water supply from the Indian Ocean
  • a lot of water was trapped in ice caps during the Ice Ages causing the world sea level to lower 100-120 m

Bordering countries

Eastern shore: Saudi Arabia, Yemen
Northern shore: Egypt, Israel, Jordan
Western shore: Egypt, Eritrea, Sudan
Southern shore: Djibouti, Eritrea, Somalia

Enhanced by Zemanta

No TrackBacks

TrackBack URL:



February 2021

Sun Mon Tue Wed Thu Fri Sat
  1 2 3 4 5 6
7 8 9 10 11 12 13
14 15 16 17 18 19 20
21 22 23 24 25 26 27

About this Entry

This page contains a single entry by Bryony published on November 29, 2010 11:11 AM.

Hurghada Serious Winter Deals - flights, hotel and diving from just £348! was the previous entry in this blog.

UNIQUE! New Year's Eve Special Thistlegorm dive trip is the next entry in this blog.

Find recent content on the main index or look in the archives to find all content.