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CELS News Article
Winter, 2007
CELS researcher escapes RI's winter for someplace colder
By: Rudi Hempe, CELS News Editor and Reporter
---------------------------------------------------------When it’s winter in Rhode Island, Dr. Brad A. Seibel seems to have a habit of
seeking a “summer vacation” elsewhere and that’s exactly what he is going to do
starting Jan. 8.
But Seibel is no winter wimp, opting for a tropical beach somewhere.
Instead he will be spending five weeks trudging along the coastal shelf ice in
Antarctica, studying the effects of carbon dioxide on certain marine life.
The research trip will include Victoria Fabry, an oceanographer at California
State University at San Marcos who was featured in an extensive article about
CO2 absorption in the oceans in a recent issue of The New Yorker magazine,
plus five students and research assistants. Seibel, an assistant professor of
biological sciences at URI, has collaborated with Fabry in the past.
They both are interested in the effects of CO2 absorption in salt water particularly
as it impacts pteropods, tiny marine organisms of which there are nearly a
hundred species.
Seibel is interested in one type that forms a shell about 2-3mm long. It has a
predator, another type of pteropod which is about 1 cm long.
The shell of the pteropod, like all shellfish, is made of calcium carbonate
(CaCO3) and there is increasing evidence that CO2 in sea water deteriorates
CaCO3 shells. The absorption of CO2 in the water creates carbonic acid which in
turn slightly lowers the pH of sea water gradually inhibiting the formation of
CaCO3 shells.
This issue of CO2 absorption in the oceans came up as a hot topic a few years
ago when it was proposed that a reduction in atmospheric CO2 in the
atmosphere could be accomplished by gathering CO2 from power plants and
injecting it in liquefied form deep into the oceans where it would remain out of
contact with the atmosphere.
Oceanic carbon dioxide absorption, whether from passive diffusion or purposeful
injection, will only pose more threats to marine life says Seibel, not only because
shell-making would be at risk but higher CO2 levels in the ocean would, for
example, inhibit other marine creatures’ ability to bind oxygen in their blood.
Seibel’s post-doc, Rui Rosa, is currently researching such effects on squid.
The ocean normally absorbs about a quarter of all the CO2 that is emitted into
the atmosphere although it is a very slow process.
While there have been lots of talk and numerous studies on CO2 absorption in
the ocean, Seibel says there is much work to be done on the deterioration of
pteropod shells. He notes that on this trip he is mainly interested in the
physiology of pteropods while Fabry is interested in the calcification process.
He and the other researchers will spend their five weeks at McMurdo Station, the
largest community on the continent that accommodates scientific endeavors.
This will be the fifth trip to Antarctica for Seibel. The first was as a student aboard
a research vessel-- his B.A. and Ph.D degrees are from the University of
California at Santa Barbara. The rest were trips to McMurdo.
At McMurdo, the researchers will be ferried by helicopters to shelf ice areas
where they will use nets to capture pteropods.
A year ago Seibel made international scientific news when he was able to
photograph a species of squid, Gonatus onyx, that guard their eggs in a sack to
protect and nurture them whereas other species simply drop them to the sea
floor to fend for themselves.
The whole issue of CO2 in the oceans is drawing worldwide interest. The
resultant carbonic acid makes it more difficult for marine life to create CaCO3
and some studies indicate by the end of this century, Antarctic waters will
become under-saturated with respect to one form of CaCO3, aragonite, which
pteropods and corals produce.
Says Seibel on his website,"My research suggests that elevated CO2
may have profound deleterious impacts on the physiology and
ecology of marine organisms."
Scientists are also concerned about the fate of coral reefs. Already there is a
process called bleaching of coral reefs in some areas of the world. The belief is
that when ocean waters get too warm, coral reefs lose their nourishing algae,
hence rendering them white. When ocean waters approach acidification, coral
reefs could be doomed, because the rate they can add aragonite will approach
the rate of losing it through bio-erosion.
Seibel says there is a great need for more research on the whole situation. "The
calcium carbonate process is relatively unstudied," he says. "There are few direct
studies."
Why do the studies in the Antarctic? Within the next 50 to 100 years, says Seibel,
surface waters of the Southern Ocean will be the first to become under-saturated
with respect to aragonite due to CO2 produced by human activities.. Pteropods
can reach densities of thousands of individuals per cubic meter in the Southern
Ocean and are functionally important components of the Antarctic ecosystem.
And why pteropods? Pteropods are mollusks (relatives of snails, clams and
squids) and because their shells are made of aragonite which is highly soluble,
these organisms may be particularly sensitive to ocean acidification. In fact, says
Seibel, pteropods are the major producers of aragonite in the world's oceans.
Furthermore, they are believed to be indicative of the overall ecosystem health in
some regions of the Southern Ocean. Another pteropod species lacks a shell as
an adult and is highly specialized to feed exclusively on the shelled form. If the
shelled species go, so do its predators.