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NEW
UNDERSEA VENT SUGGESTS SNAKE-HEADED MYTHOLOGY A new "black smoker"
--
an undersea mineral chimney emitting hot, iron-darkened water that
attracts
unusual marine life -- has been discovered at about 8,500 feet
underwater by an
expedition currently exploring a section of volcanic ridge along the
Pacific
Ocean floor off Costa Rica. Expedition leaders
from The researchers
picked that name
to highlight the presence of a pink form of the jellyfish order
Stauromedusae
as well as numerous spiky tubeworm casings that festoon the vent
chimney and
bring to mind "the serpent-haired Medusa of Greek myth," said
expedition
leader Emily Klein, a geology professor from Duke's Nicholas School of
the
Environment and Earth Sciences http://www.nicholas.duke.edu/
. The bell-shaped
jellyfish sighted
near the vent "are really unusual, and the ones we found may be of a
different species because nobody has seen types of this color before,"
added Karen Von Damm, an earth sciences professor and hydrothermal vent
specialist on the expedition from the University of New Hampshire's
Institute
for the Study of Earth, Oceans and Space http://www.eos.sr.unh.edu/. The scientists are
exploring the
ocean bottom with Jason II http://www.whoi.edu/marops/vehicles/jason/,
a remotely controlled robotic vehicle operated by WHOI. Using Jason's
mechanical arms and a temperature probe, they logged water temperatures
of 335
degrees Celsius (635 degrees Fahrenheit) at the vent's opening. "Despite the great
temperature of the vent water, it doesn't boil until 390 C because
pressures on
the ocean floor are so great, about 200 times the pressure at sea
level,"
Klein said. The tremendous pressures result from the weight of almost
two miles
of seawater pressing down from above. "Frankly, it's
astonishing
that a rich ecology thrives in these extreme environments," Klein
added.
She noted, however, that while all the organisms near vents are adapted
to the
high pressures at these depths, not all experience extremely high
temperatures. "The temperature of
the
ocean floor is about 2 degrees Celsius (35 degrees Fahrenheit) and
there is a
strong temperature gradient as you move away from the vent, so animals
living a
few inches away may experience temperatures only a few degrees above
normal for
the ocean floor." Von Damm said that
the
heat-tolerant tubeworms found living on Medusa's chimneys, a type known
as
Alvinellids, are commonplace on vents in the equatorial Pacific and
thrive on
high-iron fluids. According to the
expedition's website,
http://www.nicholas.duke.edu/OSCexpedition/,
Jason has also retrieved two other types of tubeworms -- Tevnia and
Riftia --
from the vent area for expedition scientists and graduate students to
examine
and preserve. The researchers
aboard Atlantis
are on the scene principally to study the geology of a complex section
of the
East Pacific Rise, one of the "mid-ocean ridge" systems where new
crust is made as the earth spreads and releases molten lava. According to Von
Damm, scientists
often have found mid-ocean ridges wherever there are geothermal vents
warmed by
heat energy from the underlying volcanic conduits. "Each new vent
sighting
sparks fresh excitement, because each one is different," she said. "Every vent has a
little
different chemistry, and that helps us understand the processes going
on in the
ocean crust," she said. "Each one gives us a different piece of the
puzzle. And biologists have found more than 500 new species at vents
since they
were first discovered." The Medusa vent was
discovered on
Easter Sunday morning, right after the scientists aboard Atlantis had
completed
an Easter egg hunt. Scott White, a geology professor from the "We all knew it
would be
special when we found all the creatures living there after looking at
relatively barren lava flows for several days," White said. He diverted
the robot to investigate the animals more closely and "within seconds
there was a spire of a hydrothermal chimney looming out of the darkness
at the
edge of Jason's camera lights," he added. Vent specialist Von
Damm had just
begun the watch shift when the first black smoker image appeared on a
video
screen in the Jason II control room. Since Jason's video output is also
piped
to screens elsewhere around Atlantis, Klein saw it at about the same
time. "Suddenly everybody
came
running from all over the ship to see what was going on," Von Damm
recalled. "I was smiling a lot. I was very happy." "I jumped out of my
chair
and went running up a deck to see it in person," added Duke's Klein.
"I have been going to sea for 20 years and have been hoping to find my
first hydrothermal vent site, and finally I have. "And I'm ecstatic."
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