BRITISH and Russian scientists set sail from Southampton last night on a research voyage to explore volcanoes 10,000 feet beneath the Atlantic's surface.
Around the volcanoes, seawater heated to several hundred degrees - but unable to become steam because of the immense pressure - emerges from natural chimneys up to 50 feet tall.
The existence of these volcanic hot springs or hydrothermal vents came to light less than 20 years ago. They provide a feeding ground for bacteria and a diversity of higher organisms able to exploit the mineral richness and heat of the water.
These animals are adapted to the strange conditions and may have evolved separately from the rest of life on land and sea for hundreds of millions of years.
The 55 scientists, 30 British, aboard the Russian research vessel Akademic Mstislav Keldysh will sail to the mid-Atlantic, on a latitude with North Africa, then descend almost two miles in two miniature submersibles able to withstand pressures about 400 times higher than those at the surface.
They will examine two 'vent fields', Broken Spur and Trans Atlantic Geotraverse, on the mid-Atlantic ridge, an undersea mountain range where new portions of the earth's crust are continually being created.
The chimneys are formed as sulphide minerals in the streams of hot water emerging from the sea-bed solidify. The Broken Spur vents were discovered last year by British scientists.
The joint leader of the British contingent, Dr Rachel Mills, of Southampton University, said the diving vessels carried two pilots and a scientist in cramped conditions. 'It's dark and cold, and you are down there for hours, so it's pretty uncomfortable. But what is out there is so fantastic it takes your mind off it.'
The vent sites have unusual fish and a wide range of marine invertebrates - animals without backbones such as worms, crustaceans and molluscs - adapted to the extreme conditions and feeding on each other. At the base of the food chain are bacteria which extract energy from the hydrogen sulphide dissolved in the hot water.
Dr Paul Tyler, also of Southampton University, said: 'Essentially the bacteria are using the hydrogen sulphide as an energy source instead of the sunshine that plants on the surface exploit.'
The existence of deep-sea hydrothermal vents was unknown until the 1970s when American scientists on board a submersible discovered hot springs in the Pacific Ocean.
The Russian ship is expected to return in October. The project is part of a multi-million pound, five-year programme funded through the Government's Natural Environment Research Council.Reuse content