Munich

Europe's most advanced ocean-research robot set out for an 11-week Arctic expedition last week, its most ambitious to date. Researchers hope that Victor 6000, one of the few craft that can reach depths of six kilometres, will provide insights into deep-sea corals and giant carbonate mounds — mud formations that can reach hundreds of metres in height.

“It's a fantastic tool,” says cruise leader Michael Klages, a marine biologist at the Alfred Wegener Institute (AWI) of Polar and Marine Research in Bremerhaven, Germany. “This is the first time that we will be able to fully exploit its potential.”

The €15-million (US$17.8-million) craft, developed by IFREMER, France's national marine research agency, requires some 90 tonnes of winches, cables and navigation equipment, and a 3,000-volt generator. Data and control commands are relayed to and from the mother ship, the Polarstern, by a fibre-optic cable. Video cameras and robot arms can be used to examine organisms such as tube worms and sponges.

The first stop on the cruise, which is focused on areas of Europe's continental shelf, will be the Porcupine Seabight, a deepwater basin southwest of Ireland, where Victor 6000 will survey coral reefs and carbonate mounds. The Polarstern will then set off next month for the Håkon Mosby Mud Volcano, northwest of Norway.

The volcano releases methane-rich muddy fluids, which feed huge white mats of methane-dependent bacteria. Researchers plan to use Victor 6000 to probe the sediments and to survey the extent of the bacteria-covered slopes. Among other things, this should reveal how much methane escapes from the system and dissolves into the ocean.

The cruise will finally take the team to the AWI's 'House Garden', an established research area off Spitsbergen, an island group 650 km north of Norway. One study aims to deduce how benthic engineering — natural ploughing of the sediment by snails and crustaceans — creates suitable habitats for bacteria and other microorganisms.

“The cruise is an exciting project”, says Jon Copley, a deep-sea biologist at the Southampton Oceanography Centre, UK. “Whenever someone visits the deep ocean with new technology, they almost always advance our understanding of what goes on out there.”

→ http://www.polarstern-victor.de