WASHINGTON, D.C. — After fleeing in the face of Hurricane Katrina, ocean
researchers have returned to the Gulf of Mexico where they are getting a
revealing new look at the deep sea.
NOAA/AP
The pontellid copepod Pontella securifer
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"We are exploring the deep sea with new eyes," oceanographer Tamara
Frank of the Harbor Branch Oceanographic Institution said Friday.
Frank and others aboard the National Oceanic and Atmospheric
Administration Research Vessel Seward Johnson are using a camera that
operates with dim red light to study life on the sea floor.
They have found a variety of deep-dwelling shellfish that produce their
own light, animals with surprising ability to see ultraviolet light and
a previously unknown type of squid, six feet long, that attacked their
camera.
"Imagine, something that big that had never been seen before," scientist
Edith A. Widder, who recently left Harbor Branch, said in a telephone
briefing.
When Katrina moved into the Gulf of Mexico the researchers retreated,
first to Louisiana and then to Galveston, Texas. If the storm had
continued west, Corpus Christi would have been the next stop, Capt. Aric
Anderson said.
They left the 200-pound camera on the bottom. When they returned it had
been upended, but they don't think that was done by the storm. The
camera was 1,800 feet deep, where storm effects would be minimal.
They think a large predator probably upset the camera. Unfortunately the
battery had run down so they didn't get a picture of it. They have
filmed sharks attacking the camera before.
Previous studies of deep ocean life had used bright white light or
looked at animals brought up in nets, Frank explained.
Unfortunately, the animals caught in nets are often badly damaged and
the white light blinds these deep-sea creatures.
With the red light camera they have gotten pictures of animals and even
been able to capture some and bring them to the surface without blinding
them. They are kept in dark with only dim red light which they don't
seem to be able to see.
The chambers are filled with cold seawater. The change in pressure
doesn't seem to affect animals such as crabs and shrimp, which don't
have air-filled swim bladders, the researchers said.
Some have the ability to see ultraviolet light, Frank said. They are
trying to determine why. "As far as we know there is no ultraviolet
light down there," she said. One theory is that it helps them see
creatures that produce their own biological fluorescence.
"The discovery that one of deep-sea crabs has ultraviolet vision is
thrilling," said Widder. "The question is what the heck are they doing
with it."
Some of the creatures also seem able to see polarized light, perhaps to
help them detect camouflaged predators or prey.
Witter said the camera is often left for a few days with some bait,
which attracts creatures into view.
A fake jellyfish that mimics the bioluminescent light of real jellies
has attracted several squid attacks, they said.
As many as 80 percent of animals in the deep sea produce some light, she
said.
