The Cold War
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Aboard the Calypso for the Gibraltar Survey, May 1961
The Calypso was one of six vessels working on the Gibraltar Survey, sailing under French, Norwegian, Belgian and Italian flags. Cousteau was happy to lend his ship to NATO’s expedition, but he did not participate in it himself.
Professor Lacombe (Far right) had established in previous work that three factors were interrelated: the net flow of water in one day, the distribution of barometric pressure in the Western Mediterranean and the average level of that sea.
In this photo, Professor Lacombe (Right) is observing the angle of inclination of two cables, since this influences the interpretation of recordings.
The aim of the Gibraltar Survey was specific: find factors that were easy to measure and could give daily records of the behaviour of the water in the Straits over a long period of time.
Several factors were monitored throughout the survey such as the salt content in water at varying depths and temperatures; how currents evolved at different depths; and the barometric pressure.
To measure salt content in water, the scientists used these Ekman reversing bottles, which were lowered into the sea at intervals of 50 m, to a depth of up to 250 m. The branch of oceanography that analyses salt content in water at varying depths and temperatures is called hydrology.
The scientific team observed the currents with a current meter, as seen here; current meters were lowered to different depths so that a picture would be built up of current movements.
The team also used bathythermographs, such as the one in this photo; these instruments recorded temperature and water pressure simultaneously.
Interestingly, there is an interrelation between the atmosphere and the surface of the sea, which leads to the formation of waves. As such, the team took sophisticated meteorological measurements and found it useful to study storm centres too during the six-week survey.
The Calypso and Captain Cousteau
Jacques Cousteau on board the CalypsoThe Calypso was as much a legend as its captain! Named after a nymph from Greek mythology, this former British Royal Navy minesweeper became a ferry in Malta before starting its climb to fame. The vessel was leased to former French Navy officer Jacques Cousteau from 1950 to 1997 for a symbolic one franc per year by business magnate and philanthropist, Thomas Loel Guiness.
Jacques Cousteau transformed the Calypso into an expedition vessel that would carry him and his crew across the oceans and serve as a support base for their diving adventures, filming and oceanographic research. Cousteau travelled the seas and shared the wonders of underwater research and observation with the public through a plethora of films and television series. This passionate and charismatic explorer became a household name across the globe and remained the captain of the Calypso for as long as he lived.
A few basic facts about the Mediterranean Sea were key foundations to the scientists’ research during NATO’s six-week oceanographic study:
- it loses more by evaporation than it gains by rainfall and rivers;
- the deficit of water is compensated by the inflow from the Atlantic Ocean;
- the level of the Mediterranean remains constant, as does its level of salinity. The reason? As water from the Ocean flows in, saltier and denser water from the Mediterranean flows out at a deeper level.
Read more on the Gibraltar Survey.