The summit of
Video Clipping at: http://news.bbc.co.uk/2/hi/science/nature/8419736.stm?ls
Amazing video has been obtained in the
The pictures show lavas bursting into the water at the
West Mata submarine volcano, which is sited about 200 km (125 miles) south-west
of the
The US Jason robotic submersible had to descend over
1,100 m to acquire the high-definition video.
The vehicle found microbes and a specialized
volcano-dwelling shrimp thriving in hot, acidic waters.
"It's an extraordinary environment," said
Joseph Resing, a chemical oceanographer at the
"You have molten lavas at 1,400C producing acidic
fluids—the sulphur dioxide makes these fluids as acidic as pH 1.4—and yet
microbes are thriving," he told BBC News.
"The magmatic gases sustain and provide energy for
microbial life, and then the microbes provide energy for the shrimp.
"We see them very close to the volcano—within metres."
Dr Resing has been describing the volcano's behaviour
here at the American Geophysical Union's (AGU) Fall Meeting, the world's
largest annual gathering of Earth scientists.
Rock
recycling
The
Its setting is very close to the 10,000m-deep
Tonga-Kermadec Trench. This is where the Pacific Tectonic Plate, which
comprises much of the central ocean floor, dives under (subducted) the
Australian Plate.
It is a key location for the recycling of rock back
into the interior of the Earth and it is where molten material can also then
force its way back up to the surface.
The possible existence of the eruption was first
identified in November 2008 through water samples recovered from the ocean that
contained anomalously high levels of hydrogen and volcanic debris.
But it was not until a full scale expedition took place
in May this year and Jason was able to go down and investigate
Lava flows
Jason, which is operated by the Woods Hole
Oceanographic Institution (WHOI), moved to within 3m of the erupting volcano.
The vehicle's high-definition camera captured large
molten lava bubbles about a metre across bursting into cold seawater, and it
saw glowing red vents explosively ejecting lava into the sea.
It is said to be the first-observed advance of lava
flows across the deep-ocean sea floor.
Jason's two robotic arms collected samples of rocks, hot
spring waters, the microbes, and the shrimp.
To find and study animal life in such a location was
fascinating, said Tim Shank, a WHOI macro-biologist on the expedition.
"The animal life you see down there has evolved
over millions of years to take advantage of the situation. Virtually every
species down on the sea floor at vents has some sort of novel adaptation,"
he told reporters at the AGU meeting.
"Shrimp have modified eye forms, and modified
claws to enable them to scrape certain types of bacteria. This is where
fundamental planetary processes like eruptions meet life, so it has profound
implications for me as a biologist looking at the evolution of life on this
planet."
Researchers say the volcano is spewing boninite lavas,
believed to be among the hottest erupting on Earth in modern times, and a type
only seen before on extinct volcanoes older than a million years.
"Having a very fresh occurrence—it hasn't been
altered by the ravages of time—and having a known date of eruption gives us the
ability to study many different aspects of the rock, including radioactive
tracers which will give us the rates of these processes—i.e. how long it takes
for this recycling [at subduction zones] to occur."
The
The volcano is spewing boninite lavas
http://news.bbc.co.uk/2/hi/science/nature/8419736.stm?ls
with a video clipping
18 December 2009
BBC News
Deepest volcano caught on video
By Jonathan Amos
Science correspondent, BBC News,
Jonathan.Amos-INTERNET@bbc.co.uk