or two weeks now I have watched Govenar and the others from Charles
Fisher's lab group at Penn State at work in their lab on the Research
Vessel Atlantis, sorting, slicing, bleeding, measuring, and weighing the
animals ALVIN brings up from the sea floor.
Today I finally got my hands dirty. Govenar and the rest of Fisher's group
(graduate students Sue Carney and Sharmishtha Dattagupta, post-doc Stephan
Hourdez, and undergraduate student Therese Waltz) are working on the
Riftia pachyptila, or giant tubeworms, that came up in today's sample.
They warned me that the worms were still "a little bit alive," and that
they might retract into their tubes or flinch when I touched them. The
idea didn't appeal to me, but I had to prove myself to these young
scientists who had too many times put up with my exclamations of
"EEEeeeew!" as they worked.
They set me up with a measuring tape, some string, a razor blade, a
caliper, several beakers, a bucket of filtered sea water, and a slop
bucket, and I went to work cutting open the thick white tube to get at the
soft and vulnerable worm inside.
A tubeworm, when removed from its protective tube, looks like a cross
between a common earthworm and something out of science fiction. Besides
being larger (sometimes much larger — up to a meter long), Riftia's
vestimentum and plume set it apart from the earthworm. That and the fact
that they live on the ocean floor, have no mouth, or gut, and get energy
from potentially toxic chemicals processed by sulfide-oxidizing bacteria
living inside of them.
Cutting open the tube is the easy part. It's picking up and measuring the
soft red worm inside that was a challenge for me. I felt like I held a
creature from another planet.
The first time a seemingly dead worm flinched in my hand, I shrieked and
tossed the worm onto the lab table. A wave of shivers went down my spine.
I realized that I would be more comfortable if this creature were already
dead. I looked around to see if anyone had noticed my reaction, and
Govenar, ever reassuring, smiled and told me that it startles her too
sometimes.
Therese Waltz, the only undergraduate on this cruise, teaches me a little
about the anatomy of the tubeworm. She points to the strange piece of
flesh that wraps around the worm like a vest just above its middle and
explains that it is the vestimentum, the muscle they use to hold their
plume, the top part of the tubeworm, outside of their tube so that it can
pick up the nutrients it needs to survive.
"Ooh, I've got a bleeder here," says Sharmishtha Dattagupta, working
across the table from me, when she nicks the flesh of the worm she is
working on. Blood drips and then pours from the worm, and Dattagupta,
conscious that the loss of blood affects the precision of the volume
measurement she wants, is quick to move the bleeding worm over a beaker,
turning the beaker water pink and then deep red.
Sometimes you don't have to cut the tube at all, Dattagupta tells me. You
can squeeze the worm right out of the tube. "Like deep sea toothpaste,"
she says as she presses the tube flat at one end. Plop goes the worm into
the beaker.
The scientists patiently teach me how to tell a male Riftia from a female,
correct me with a smile when I call the vestimentum a vestibule, and
congratulate me on each correctly weighed and measured worm.
The work is tedious and slow and hard on the body. After only a couple of
hours spent bent over the tubeworms, my neck is stiff, my eyes are tired,
and my fingers are pruney from the seawater that spills from the tubes.
But this is just a small sampling for me of the scientists' life. To
properly study community ecology of vent sites, every animal from a
quantitative sample must be identified, counted, weighed and measured.
Hours of sorting go on before you even get to this point of looking at the
specifics.
I was proud (and relieved) that in the time I worked in the lab, even with
the rocking of the boat, I didn't have a single bleeder.
Special thanks to Sophie Pendlebury of the University of
South Hampton, U.K., for her patience in talking me through the amazing
amount of science that goes on at the hydrothermal vents. Also, thanks to
Chuck Fisher, Breea Govenar, Sue Carney, and Stephan Hourdez, all of Penn
State, and to Cynthia Kicklighter of Georgia Tech for clearing up a few
of my questions, and to Greg Ravizza of Woods Hole Oceanographic Institution
for his encouragement and enthusiasm.
And thanks to Cindy Lee Van Dover for writing two great books about
hydrothermal vents, "Octopus's Garden" and "The Ecology of Deep-Sea
Hydrothermal Vents."
Next Dispatch:Cruisin' Christmas
ost of us think of the sea floor as a vast, lifeless expanse — nothing to
see, nothing to study. But over the last twenty-five years, scientists
have discovered lush communities of life thriving at hydrothermal vents on
the ridges and rises of the ocean floor. No visible light reaches this
environment, oxygen concentration can be extremely low, potentially toxic
sulfide levels are high, and heavy metals are rife. Not what you'd call
ideal conditions for most animals we are familiar with.
enn State graduate student Breea Govenar, whose work on this cruise is
crucial to her Ph.D. thesis, is looking at the community ecology of
hydrothermal vents.
