GOING TO EXTREMES
By Sean Henahan, Access Excellence
Francisco, CA (July 29, 1997)- A new form of centipede-like worm thriving
on deep sea deposits of frozen methane is the first animal ever found living
under these harsh conditions.
A team of scientists has been exploring mounds of methane ice
found on the ocean floor in the Gulf of Mexico. Methane ice forms naturally
at the high pressure and low temperature of the deep sea, but is usually
buried deep in marine sediment. The Gulf of Mexico is one of the few places
where hydrate can be found exposed on the ocean floor. In some cases, the
methane forms into yellow and white mounds as much as sixteen feet across.
Caption: Close-up photo
shows a dense colony of one-to-two inch-long polychaete worms living on
and in the surface of the methane hydrate. (Photo credit: Charles Fisher,
While scientists have suspected that bacteria might colonize these ocean-floor
ice mounds, known as gas hydrates, the discovery of the worms came as quite
a surprise. Scientists believe they may discovered a new species with a
unique interrelationship with these methane deposits.
The scientists observed dense colonies of the 1-inch-long flat, pink
worms- called polychaetes- living on the mounds. The blind creatures use
two rows of oar-like appendages to move throughout the honeycombed, yellow
and white surface of the hydrate mound.
The worms were first spotted only two weeks ago by Dr. Charles Fisher
of Pennsylvania State University, chief scientist of the expedition. The
worms were discovered during an 1,800- foot-dive in the deep-sea submarine
known as the Johnson Sea Link.
"These are not just another common worm in the mud," says Fisher. "These
are higher order organisms that can live right on methane hydrates. If
these animals turn out to be ubiquitous on shallow sea-floor gas deposits,
they could have a significant impact on how we go about mining or otherwise
harvesting this natural gas as a source of energy."
Another team member, Dr. Alissa Arp, director of SF State University's
Romberg Tiburon Center for Environmental Studies, is now studying live
specimens in her lab in order to determine how the animals can thrive in
such inhospitable conditions.
"Biologists are always thrilled to find a new organism that has such
an intricate strategy for inhabiting such a remote and hostile environment.
We've discovered that the worms have a fully developed digestive tract.
This means they are either grazing off chemosynthetic bacteria living directly
on the methane, or, the relationship may be more symbiotic. They may be
farming this type of bacteria on their appendages," Arp reports.
A second leg of the expedition is now underway.