23 January 2010
Here we are, clear at the other end of the Red Sea, between two continents. We are going through the Gate of Tears: “Bab-El-Mandeb” in Arabic. According to an old legend, it’s named after the laments of the drowned souls who died during the earthquake which tore Asia from Africa. According to another legend, the name is simply meant to warn travellers of the danger that lies in passing through it.
Bab-El-Mandeb is at the tip of the South-East end of the Red Sea, towards the Indian Ocean. Seen from here, Asia and Africa seem fairly close to another: About fifteen knots. The passage is 40 miles long, and is sprinkled with small islands such as the Islands of the Seven Brothers, or Perim Island which splits the strait in two, thus creating a navigation lane for oceanic ships on one side, and a coastal navigation lane on the other. These little islands are actively used by fishermen, as stopovers or shelters as they cross the strait.
The marine currents which flow through the strait are complex phenomena, and this particular strait is quite special. In the North, the Suez Canal bears its name for a reason: it’s a canal, not a channel. Water exchanges happen here, from the South. Contrary to what you might have though, the Red Sea isn’t completely closed on itself. Currents coming from the Indian Ocean and the Gulf of Aden deliver the essential part of the nutrient salts (or fertilzer) the Red Sea needs, and keep flowing towards the North, slowly dwindling as they are absorbed by phytoplankton.
The Red Sea acts like an evaporation pond; as the water evaporates, the seawater salinity’s increases and it becomes colder, therefore denser. The water then sinks deeper down and forms deep sea currents which cross the Red Sea in the other direction: from North to South, finally leaving the strait, “kind of like a moving walkway” as Fabrice Not – our chief scientist – likes to say. Consequently, the major part of the Red Sea’s biomass is concentrated in the South.
As for navigating, crossing this channel is far from easy! Three different forces drive the currents: the monsoon, the tide and the local winds. Therefore, what characterizes these currents is variability from the dominance of one of those three. The monsoon is a periodical atmospheric current found in the inter-tropical zone of the globe. It is due to the crossing of the equator by trade winds. In this part of the globe, the monsoon is quite probably THE determining factor when it comes to meteorology.
During the monsoon – from May to October- in the area of Bab-El Mandel, the sea level in the gulf of Aden falls, tends to become lower in the Red Sea, and the surface current flows in a South, South- East direction. From November to April, the opposite phenomenon occurs and the surface current goes North, North-West.
During times of strong wind and lively water, when the wind is blowing against the current’s direction, the surface of the water becomes highly agitated. Legends warning navigators weren’t created simply to give the traveller an empty scare, places such as the Gate of Tears require the utmost attention and care upon crossing.
Another major aspect of this bottleneck lies in its strategic importance. Bab-El- Mandeb, the channels of Ormuz and the Dardanelles are the only three navigable straits which cannot be circumvented, which makes them crucially important.
The Bab-El-Mandeb passage became important at the end of the XIXth century -when the Suez Canal was opened for navigation- thus making the Red Sea an optional route allowing ships to avoid going around Africa, through the cape of Bonne Espérance. The two colonial powers of the time, France and England, created two naval bases to regulate its access: Djibouti and Aden, which to this day remain the two locks guarding the channel.
Terrorist attacks directed against the American embassies in Nairobi (Kenya) and Dar Es- Salaam (Tanzania) in 1998, as well as the 2000 attack on the USS Cole destroyer in Aden have lead to the opening of an important American military base in Djibouti in 2002. 1800 American soldiers, including approximately 900 of the special forces are currently stationed in Camp Lemonier, an old French Foreign Legion base, and with the French keep this passage, through which 3.3 millions barrels of oil transit daily, secure.