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5 December 2013 11:26 am ,
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Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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Hot, Deep Vents Without Fireworks
18 June 2002 (All day)
At the bottom of the world's oceans, mountain ranges run along the boundary of tectonic plates, pushed up by rising molten rock that also heats water that spews out of vents found along the ridge tops. Oddly, some maverick hydrothermal vents exist far from the spine of the ridges and their reservoirs of magma. Now, a mathematical model shores up speculation that the furnace for these distant vents is a chemical reaction between seawater and rock exhumed from deep within the planet.
Marine geologists have known for years about the sizzling mix of seawater and peridotite--a greenish rock from Earth's mantle that is sometimes pushed up through the crust. The result is a soapy-textured rock called serpentine. But geophysicist Robert Lowell at the Georgia Institute of Technology in Atlanta said he never believed the reaction could produce enough heat to power a hydrothermal vent until a vent was discovered in 2000 in the Atlantic Ocean, atop a region of peridotite and away from the volcanically active backbone of the mid-ocean ridge. Waters from the vent site were a respectable 40° to 70°C, but hardly the scalding 200° to 300°C observed in vents near magma sources--which suggested that something other than magma might be at work.
So Lowell and Peter Rona of Rutgers University in New Brunswick, New Jersey, set out to determine the range of water temperatures that might issue from a hydrothermal vent on top of a mass of peridotite. They tallied the heat released for every kilogram of peridotite converted into serpentine and estimated how fast water moved through the vent system. They found that extra heat from magma may not be necessary; temperatures produced by a vent system like the one found in 2000 could be reached just by the seawater-rock interaction, the pair reports in the 14 June issue of Geophysical Research Letters.
This is the first demonstration that the peridotite conversion can create a "good-sized" temperature hike like that observed in the off-ridge vent, says chemical oceanographer David Butterfield of the Pacific Marine Environmental Laboratory in Seattle, Washington. But Butterfield questions whether the model can nail down any details of specific hydrothermal vents, because many of the model's variables, such as the amount of peridotite or flow rates in the crust, are very difficult to confirm.