Worms open route to whale bones
g.read at niwa.co.nz
Sun Sep 14 21:26:55 EST 2003
"It's a new polychaete, a new genus and species, and we think it's unique to
SCIENCE, Volume 301, Issue 5639,
dated September 12 2003
Report from: 4TH INTERNATIONAL SYMBIOSIS SOCIETY CONGRESS:
"About 2 years ago, Shana Goffredi and her colleagues came across sunken
treasure on the sea floor of California's Monterey Bay. It wasn't gold coins
that got them excited but the body of a recently dead whale lingering on the
sea floor 3000 meters deep. "It's one of the deepest known whale falls," and
deeper than most scavenger fish dare to go, said Goffredi, a marine biologist
at the Monterey Bay Aquarium Research Institute in Moss Landing.
Using a remotely operated sub, the researchers discovered what appeared to be
a carpet of red fuzz on the whale's corpse. That fuzz proved to be thousands
of polychaetes, segmented worms typically found in marine mud. The worms' red
plumes stuck out about 6 centimeters into the water and, with about 25
individuals per square centimeter, gave the carcass a rosy tint. "It's a new
polychaete, a new genus and species, and we think it's unique to whale falls,"
Goffredi reported at the meeting.
No one was surprised by the worm's plumes, typical "tentacles" that filter
food from the water. But in addition, "the worms just riddled the [whale]
bones with strange roots," Goffredi said. Surprisingly, the roots were chock-
full of bacteria. She wondered whether the bacteria played a role in making
the bones fragile and soft, and how the microbes secured a safe haven in the
worms' roots. "The question is, Is [the microbe] a symbiont?" she asked.
One bit of evidence for symbiosis was that "the worm doesn't appear to have a
functional mouth or gut," Goffredi said; "it has no way to feed itself." Thus
the worm probably relies on carbon compounds produced by the bacteria as they
feast on oil oozing out of the whale bones.
In return for this nourishment, specialized cells in the worms' roots provide
housing for the bacteria. Goffredi, Greg Rouse of the South Australian Museum
in Adelaide, and their colleagues found none of these microbes outside the
roots. And the worm "probably provides oxygen," via a blood vessel extending
into the roots, she added.
Molecular analyses support the idea that the microbes feast on whale oil. They
are related to bacteria that thrive in oil-contaminated soil, where they "eat"
hydrocarbons. If it is truly a symbiont, this microbe would be the first
hydrocarbon degrader known to form any symbiotic relationship, Goffredi
"One of the exciting things ... in the deep sea is you find new creatures,
sometimes very weird ones," says Charles Fisher, a marine biologist at
Pennsylvania State University, University Park. "If the environment requires
unique adaptations that cannot be accomplished via one organism, then almost
certainly two or more organisms will find a way to make it work."
Volume 301, Number 5639, Issue of 12 Sep 2003, p. 1467.
Copyright The American Association for the Advancement of Science.
Geoff Read <g.read at niwa.co.nz>
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