|
 Dr.
Monika Bright, associate professor of marine biology
and zoology at the University of Vienna, Austria, decided
that the deep sea was where she wanted to focus her
research after her first dive in the submersible Alvin in
1992.
"I got hooked on the giant tubeworms," she
says.
These
lipstick-like worms, which can grow up to 8 feet tall,
have no eyes, mouth, or gut (stomach). They survive
thanks to a
mutually beneficial partnership -- a symbiotic relationship
-- with billions of bacteria that live inside them.
The worm provides the bacteria with a home, and the
bacteria convert the toxic chemicals that spew out
of the vents into worm
food.
During
the Extreme 2004 expedition, Dr. Bright and her research
team will be working to learn how and when the bacteria
take up residence in the tubeworm.
"We
know that each generation of tubeworms has to acquire
its symbiotic bacteria from the environment," Dr. Bright
says. "We are investigating how and when
this occurs. After
a tubeworm larva has been spawned and has settled to the seafloor, it undergoes
a dramatic metamorphosis. Shortly thereafter, it
takes on a
specific bacterial partner. We believe this is
achieved through an infection in the worm's skin and not by uptake through
the digestive tract, as postulated
earlier," she
notes.
To
investigate this infection process, Dr. Bright and
her colleagues will be collecting baby
tubeworms using Vestimentiferan Artificial Settlement
Devices (VASDs) deployed in a hydrothermal vent field
and then examining the organisms in
the lab.
"The
tubeworms depend entirely on their symbionts and yet
they don't pass them on to their offspring. Why
not? -- For me, this was always an intriguing question," Dr.
Bright notes. "Knowing
the mechanism of transmission will not only give us
insight into the evolution of this deep-sea association
but also the evolution of symbiosis in general."
Dr.
Bright is sharing Extreme
2004 with students in Austria using
University of Delaware educational materials translated
into German. Visit her German Web site at http://www.hydrothermalvent.com. Her
research is funded by the Austrian Science Foundation. |
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Resembling giant lipsticks, tubeworms (Riftia pachyptila) live over a mile deep on the Pacific Ocean floor near hydrothermal vents. They may grow to about 3 meters (8 ft) tall. The worms' white tube home is made of a tough, natural material called chitin (pronounced "kite-in").
Tubeworms
have no mouth, eyes, or stomach ("gut"). Their
survival depends on a symbiotic relationship with billions
of bacteria
that live inside them. These bacteria convert the chemicals
spewing out of the vents into worm food. This chemical-based
food-making process is known as chemosynthesis.
The
bright-red plume is the tubeworm's breathing apparatus. The
blood in it contains special forms of hemoglobin that have
a super-high affinity for the oxygen in the seawater. Masses
of tubeworms, with their showy plumes, inspired scientists
to name one vent field "The Rose Garden" in 1979.
However,
during an expedition that began in May 2002, scientists from
Woods Hole Oceanographic Institution and NOAA's Ocean Exploration
Program found that "The Rose Garden" may have been
covered over with lava from a recent volcanic eruption. They
found a thriving new site nearby that they named "Rosebud." For
more details, read the story on
the Woods Hole Web site.
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