First exploration of Antarctica's vents and seeps
8 January 2009
UK scientists are set to be the first to investigate in detail the creatures living around hot water vents surrounding the coldest continent, Antarctica.
Some scientists think that life on Earth may have originated around hydrothermal vents.
The team, who leave the UK today, join the British Antarctic Survey's research ship the RRS James Clark Ross in Puenta Arenas, Chile, on a voyage to locate and explore life around two poorly-understood deep-sea habitats - hydrothermal vents and cold seeps.
Hydrothermal vents, or black smokers, were only discovered in 1977. Scientists investigating the floor of the Pacific Ocean found vents gushing hot mineral-rich fluids into the water.
To their amazement, communities of creatures and microbes were thriving in these extreme conditions. Since the discovery, vents in the Atlantic Ocean (1984), Indian Ocean (2000) and the Arctic Ocean (2001) have been located and investigated.
Some scientists even speculate that life on Earth may have originated around hydrothermal vents.
Cold seeps, or undersea natural gas leaks, were first discovered in the Gulf of Mexico in 1984 and have since been found in other oceans, including beneath an ice shelf in Antarctica. Like hydrothermal vents, seeps provide the necessary ingredients to support isolated pockets of life in the pitch-black depths.
The first vent was discovered in 1977.
Both phenomena are known as 'chemosynthetic', because, unlike photosynthetic ecosystems that derive their energy from the sun, they use chemicals from the vent or seep for their energy supply.
Since their discovery, marine biologists have found more than 650 species in these isolated habitats, including mussels, clams and shrimps.
Marine scientists have been intrigued by the discovery that vents and seeps around the world have many similarities and many differences. The giant tubeworm, Riftia pachyptilla, for example, lurks around some Pacific vents but has not yet been sighted around vents in the Atlantic, Indian or Arctic Oceans.
This latest expedition will be the first to explore both phenomena in any detail in one of the world's most hostile places, the Southern Ocean. The five-week NERC-funded project called ChESSO, or Chemosynthetic EcoSystems in the Southern Ocean, is part of a much larger ten-year scientific initiative known as the Census of Marine Life.
The Southern Ocean connects the world's great oceans - the Atlantic, Pacific and Indian. The team are focusing on a few small regions in the Southern Ocean, including the East Scotia Ridge and the Bransfield Strait - between the tip of South America and the Antarctic Peninsula.
The East Scotia Ridge (top box) and the Bransfield Strait.
Deep-sea biologist and principal investigator, Professor Paul Tyler from the National Oceanography Centre, Southampton (NOCS), says, 'It is one of the most isolated places on Earth, which is why no one has attempted it before.'
'South of the polar front [about 60 degrees south] we don't know if there are any chemosynthetic environments,' explains Tyler.
There are signs, though, that they exist beneath the ice floes. Ten years ago, the BRIDGE project, funded by the Natural Environment Research Council, located two plumes on the East Scotia Ridge.
The researchers, led by Dr Rob Larter from the British Antarctic Survey, believe the sources of these plumes are two hydrothermal vents two and a half kilometres beneath the surface. But the precise location is unknown. Larter is the chief scientist on this latest mission.
'We want to relocate these plumes,' says Tyler.
'Vents in the Pacific support tubeworms, mussels and clams. In the Atlantic it's shrimps, mussels and anemones. We want to test if there are any links between these oceans and life on the East Scotia Ridge.'
'If we find shrimp on the ridge we well have found a tentative link to the Atlantic.'
But the world's strongest ocean current, the Antarctic Circumpolar Current, moves in the opposite direction, heading west to east from the Pacific into the Atlantic.
'It is possible that this current carries larvae from the Pacific into the Southern Ocean.'
ChESSO project manager Dr Maria Baker, also from NOCS, says, 'The primary objective is to evaluate whether these sites represent a Southern Ocean "gateway" to enable gene-flow from the Pacific Ocean to the Atlantic Ocean.'
The British Antarctic Survey's research ship the RRS James Clark Ross
'Perhaps we will find that the vents and seeps here act as stepping stones for creatures from the Pacific to reach the Atlantic vents and vice versa,' says Baker.
After East Scotia Ridge, the James Clark Ross travels east in search of seeps off the South Sandwich Islands.
Once they have homed in on potential sites, the team will drop video and stills cameras down on a piece of equipment known as a 'Shrimp'. They also plan to measure and analyse the chemical composition and currents surrounding the vents and seeps.
The current expedition involves scientists from the British Antarctic Survey, the National Oceanography Centre, Southampton, the Zoological Society of London and Woods Hole Oceanographic Institution in the USA.
The Census of Marine Life is a global network of researchers in more than 80 countries studying the diversity, distribution and abundance of life in the oceans.
The project plans to release the world's first comprehensive census of marine life - past, present and future - in 2010.
ChESSO researchers are working with NASA to develop programmes to search for life on other planets or moons.
The team begin the expedition on 14 January and finish 18 February. They will be reporting regularly on the classroom@sea website www.classroomatsea.net
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