Source: Planet Earth Online.com - Feb 14,2012, Harriet Jarlett
An expedition in search of hydrothermal activity has found an unusual volcanic feature in Antarctica, near the South Shetland Islands.
Hydrothermal vents like this are normally teeming with life
Underwater springs of hot gas and water, called hydrothermal vents, are known for the wealth of life that surrounds them – nourished by chemicals dissolved in their hot water. So scientists from the National Oceanography Centre were shocked to find one of these vents barren and leaking cool water instead.
The team went looking for a vent in this area, expecting to see the usual animal menagerie, but when they didn't find it, they were alerted to something much more unusual.
Images from the underwater camera they were towing behind the research ship showed a haze seeping out across the seafloor, like the shimmer you see near the ground on hot days. These iridescent horizons occur where water of two different types meet, so water from the vent has to be very different to the Antarctic waters it's pumped into.
The scientists expect that the volcanic vent has a different salt content to the Antarctic seawater, and its cooler temperatures prevent's it rising up like a classic vent would.
The newly named Hook Ridge Vent may once have been warmer, like its better known counterparts, as shown by a derelict pipe of minerals that its waters once flowed through. But this proves it is too changeable to support life, even life used to these hostile conditions.
The animals that are extreme enough to survive on these dark and dangerous vents could help us understand how life evolved, even when the Earth was inhospitable.
