Europe's largest fleet of underwater robot gliders is about to embark on its first research mission in the tropical Atlantic.
The gliders, operated by Germany's Leibniz Institute of Marine Sciences (IFM-Geomar), can explore the oceans at a depth of 1,000 metres, while using no more energy than a bike-light.
The payload of the two-metres-long yellow diving robots consists of modern electronics, sensors and high-performance batteries. The gliders transmit research data in real time, and can be contacted via satellite telephone and programmed with new mission parameters.
"Ten year ago we started to explore the ocean systematically with profiling drifters. Today, more than 3,000 of these devices constantly provide data from the ocean interior," explains Professor Torsten Kanzow, oceanographer at IFM-Geomar.
But, he says, there's one big problem: the route of the drifters can't be controlled.
"The new gliders have no direct motor, either. But with their small wings they move forward like sailplanes under water," says IFM-Geomar's Dr Gerd Krahmann.
The gliders zigzag up and down between a depth of 1,000 metres and the sea surface. They can work away on their own for months, and are equipped with instruments to measure temperature, salinity, oxygen and chlorophyll content as well as the turbidity of the sea water.
After final tests the robots will be released in March 2010 about 60 nautical miles north-east of the Cape Verde islands. For two months they will investigate physical and biogeochemical features of the Atlantic.
The aim is to get a better understanding of water circulation and stratification, as well as their impact on chemical and biological processes. The gliders will be remotely controlled from a control centre at IFM-Geomar in Kiel.
The gliders are manufactured by Teledyne Webb Research.