August 4, 2008

Scientists Discover Hottest Water On Earth

Deep beneath the surface of the Atlantic Ocean, geochemist Andrea Koschinsky says she has discovered the hottest water ever to be found on Earth.

"It's water, but not as we know it," she said.

The fluid can be seen flowing from two black smokers, named Two Boats and Sisters Peak, more than 3 kilometers below the surface of the ocean. It is in what scientists call a "supercritical" state that has never been seen before.

Koschinsky said the fluid is in between a gas and a liquid, and could offer new insight into how essential minerals and nutrients like gold, copper and iron are leached out of the entrails of the Earth and released into the oceans.

When temperatures and pressure increases, the gas and liquid merge, creating one supercritical fluid.

Water and seawater have both been pushed past this critical point in labs, but until Koschinsky and her colleagues sailed to just south of the Atlantic equator in 2006, no one had seen supercritical fluids in nature.

Alongside a team of scientists, Koschinsky set out to investigate the southern end of the mid-Atlantic Ridge.

They discovered the black smokers in 2005 and returned in 2006 and 2007, while gauging temperatures each time.

Temperatures in 2005 were at least 407 °C, and even reached 464 °C for periods of 20 seconds.

"We stand to greatly improve our models of fluid circulation and heat and mass transfer," says Margaret Tivey, a geochemist at the Woods Hole Oceanographic Institute (WHOI) in Massachusetts.

"It's not yet possible to drill into active vents," explains Koschinsky. "Temperatures are so high, much of drilling equipment would melt and joins would not work anymore." The data from the new vents will be invaluable in testing the models.

"The findings are significant," says Dan Fornari, also of WHOI. "The high temperature of the venting is especially interesting as this [mid-ocean ridge] does not spread very rapidly."

Scientists believe that the two smokers have been active since an earthquake occurred in 2002.

"The magma body underneath is probably enormous," says Koschinsky.

However, Colin Devey of the University of Kiel in Germany said: "The explanation could be that there's lot of magma, but after a few more years of high temperatures, it's going to get to the point where it will be embarrassing how much magma there needs to be to maintain them for that long."


Image Caption: A black smoker (Image: NOAA)


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