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Polar
bear discovers what seems to be a tasty snack
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During the ICEX 2003 naval exercises near the
North Pole, the American submarine Connecticut (SSN 22), one of the new
Seawolf class, poked its sail and rudder through the ice last April 27th.
When an officer looked around outside via the periscope, he was shocked to find
his sub being stalked by a hostile polar bear. The periscope camera was turned
on, and caught the bear chewing on the sub’s rear rudder. The damage was
minor, partly because the Connecticut was not designed to be a polar bear
snack.
At
nine feet (three meters) tall, a polar bear is literally at the top of the food
chain. With no natural enemies, predatory cunning and voracious appetites,
polar bears are the dominant land animals of the Arctic.
But
all is not well for the white-furred masters of ice and snow.
Pollution
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Polar
bear wrestles with submarine rudder relentlessly attempting to bite off a
chunk
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Since
polar bears are at the top of the food chain, they are highly susceptible to
chemical pollutants that bioaccumulate in animals. For example, PCBs
(polychlorinated biphynols), an industrial product that concentrates in fatty tissue, are a pollutant still threatening the creatures. The presence of PCBs is a suspected cause of birth defects that have been
occurring in Norwegian populations.
In
addition to PCBs, scientists are concerned over the increasing amounts of other
global pollutants such as other types of organochlorines, radionuclides, and
heavy metals. Recent studies have linked these with a weakening of polar
bears’ immune systems and effects on the bears’ endocrine systems.
Climate
Change
Climate
change is also affecting the animals. The Polar Regions are the first to
suffer the consequences of global warming. Also because the Arctic
ecologies are so simple and interrelated, the area is disproportionately
vulnerable to small changes in the environment. In a nine-year study to mimic
the effects of warming on the tundra, one study showed that species richness
dropped between 30 percent and 50 percent.
This
simplification of the habitat can reduce the diversity of the secondary species
that rely upon it, and repercussions can easily make their way up the food chain
to the top carnivores.
Simultaneously,
both the coverage and thickness of sea ice in the Arctic regions has decreased 6
percent between 1978 and 1996 based on satellite images. How much is that? The
Arctic sea ice covers an area almost equal to the size of the United States, and
each year an area roughly twice the size of New Jersey disappears. The average
thickness of the Arctic ice has also thinned based on submarine sonar
measurements, shrinking from 10.2 feet in 1960, to 5.9 feet now. A reduction of
42 percent in only the last 40 years.
The
ice along Greenland’s ice sheet has also thinned, losing more than 1 meter a
year since 1993. Although changes in temperature and ice depth are not uniform
throughout the Arctic, there has been a general warming trend. Simply stated,
the ice is melting!
This
climatic change has already shown significant effects on the southern-most polar
bear populations at western Hudson’s Bay, Canada. Researchers there have noted
that polar bears are 10 percent thinner and have 10 percent fewer cubs than 20
years ago (Stirling et al. 1999). Polar bears hunt their prey, predominantly
ringed seals, from the ice.
Because the ice in this region melts completely each summer, the bears have
adapted a strategy of coming ashore near Churchill, Manitoba, at the end of July
and fasting until the ice again freezes in November. To overcome these months of
fasting, the bears must accumulate an adequate reserve of fat before the ice
breaks up. But break-up is now occurring an average of 10-14 days earlier than
20 years ago (this past season break-up was four weeks earlier). The bears are
arriving onshore about 40 pounds lighter for each week earlier break-up occurs.
This is most critical for females nursing new cubs. The mothers simply don’t
have enough fat reserves to produce enough milk for their offspring to survive. At
the same time, the birth rate is down 15%. For these slow reproducing,
long-lived animals this can quickly spell trouble.
Our
submarine-eating polar bear was obviously trying to solve some of his own
problems.
Should
Polar Bear File Suit Against US?
American
submarines have been operating under the Arctic ice for over half a century,
ever since the USS Nautilus first passed under the ice at the North Pole in
August 1958. Two U.S. nuclear subs surfaced at the North Pole in 1962. All
of this arctic activity was to prove that nuclear subs could operate up there,
and that ballistic missile subs could launch their missiles there as well.
American and Russian subs have been operating up there ever since.
In
fact these submarines, using their sonar to measure the ice thickness, have
demonstrated the 40% reduction in ice thickness, most if it occurring in the
past 20 years. Scientific opinion currently holds this is due to a combination
of global warming and the normal fluctuation of Arctic ice thickness.
Submariners
have seen polar bears in the past, but this is one of the few times that the
bear saw the sub first, and apparently mistook it for the world's largest chunk
of bear food. Ironically, this could cause legal problems for the captain of the
Connecticut. The Marine Mammal Protection Act of 1972 makes it illegal
for "any person or vessel subject to the jurisdiction of the United States
. . . to take any marine mammal on the high seas." "Take" is
defined to include "harass," and "harassment" means, among
other things, "any act of . . . annoyance which has the potential to
disturb a marine mammal or marine mammal stock in the wild by causing disruption
of behavioral patterns, including, but not limited to, migration, breathing,
nursing, breeding, feeding, or sheltering . . ." The polar bear in this
situation was "disturbed" and "annoyed" to discover that
what appeared to be a huge meal from under the ice turned out to be an inedible
U.S. submarine. This can be construed as "disruption" of the bear's
normal feeding pattern, thus making the U.S. Navy liable to legal action.
Sources:
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Chapin,
F. S. III, G. R. Shaver, A. E. Gilblin, K. J. Nadelhoffer and J. A. Laundre.
1995. Responses of arctic tundra to experimental and observed changes in
climate. Ecology 76:694-711.
-
Derocher,
Andrew E., Gerald W. Garner, Nickolas J. Lunn and Oystein Wiig (Eds) 1998.
Proceedings of the Twelfth Working Meeting of the IUCN/SSC Polar Bear
Specialist Group, 3-7 February 1997, Oslo. Norway. Occasional Papers No. 19.
159 pp.
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Halsey,
L. A., D. H. Vitt and S. C. Zoltai. 1995. Disequilibrium response of
permafrost in boreal continental western Canada to climate change. Climatic
Change 30:57-73.
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IUCN.
2001. Press Release of the 13th Meeting of the IUCN Polar Bear
Specialist Group.
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Kwong, Y.
T. J. and T. Y. Gan. 1994. Northward migration of permafrost along the
Mackenzie highway and climatic warming. Climatic Change 26:399-419.
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Stirling,
Ian, N. J. Lunn and J. Iacozza. 1999. Long-term trends in the population
ecology of polar bears in western Hudson Bay in relation to climate change.
Arctic, 52: 294-306.
David
Tschanz is a medical/military historian currently based in Saudi Arabia.
He is also an epidemiologist, web developer, editor and demographer. You may
contact him by sending your emails to: Desertwriter1121@yahoo.com.
