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| May 16, 2004. 01:00 AM |
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It's a waterlogged Arctic puzzle
Arctic researchers studying impact of climate
change
Chemical assault plays havoc with polar
ecosystems
PETER
CALAMAI
SCIENCE WRITER
ABOARD CCGS AMUNDSENAfter five weeks aboard an
icebreaker in the Arctic Ocean, researcher Gary Stern headed
home last week, with 200 kilograms of seawater in seven cooler
chests following as extra baggage.
Painstaking analysis of the water at Winnipeg
laboratories should help start deciphering a big environmental
puzzle: How much will climate change worsen the chemical
assault on the Arctic?
And those coolers packed with half-litre bottles
represent just a small portion of the extensive samples that
Stern, lab technician Joanne Delaronde and other colleagues
are gathering during 11 months aboard the Amundsen, Canada's
first research icebreaker.
There are samples of Arctic cod, plankton and other
marine creatures, filters from high-capacity air samplers and
much, much more water some collected from under sea ice;
some representing thin layers of snow; some that used to be
ice; and microscopic residues from tens of thousands of litres
sucked through submerged pumps.
Measuring concentrations as low as parts per trillion
for as many as 200 chemicals in these samples will cost
roughly $400,000 and take more than a year, says Stern, an
expert in Arctic contamination with the federal fisheries
department and an environment professor at the University of
Manitoba.
There are also isotopic signatures to be checked that
reveal the source of the water and where the various marine
creatures acquire the carbon they convert into carbohydrates.
But don't expect all these measurements to produce easy
answers.
"We don't really understand what is happening with
contamination processes here now, much less what may happen
with climate change," says Stern.
The challenge for researchers engaged in the
multi-year, $66 million research mission is not only the
complexity of the physical, chemical and biological processes
in northern ecosystems but also the benign neglect of Arctic
science by successive federal governments over the past three
decades.
Even in a southern and relatively populated region of
the Arctic, like Hudson's Bay, scientists can only guess at
the variety of fish and their numbers essential basic
information for projections of climate-change impact.
What's not in question is the tainting of the
once-pristine Arctic environment by chemicals wafted here from
industry, agriculture and human endeavours elsewhere, as far
away as China and India.
Traces of a ubiquitous flame retardant have been found
in the Arctic's most remote corners.
In the western Arctic, mercury has reached parts per
million in beluga whales.
In Norway's Spitzbergen, gender-bending PCBs are blamed
for polar bears that are hermaphroditic, with both male and
female sexual trappings in the same animal.
It's not all gloom.
Levels of pesticides and other organochlorine compounds
are now dropping in marine mammals in the eastern Arctic and
the PCB contamination of beluga in the St. Lawrence River can
still be 100 times higher than that of their Arctic-dwelling
counterparts.
But along the St. Lawrence, people merely watch the
whales. Here, the Inuit eat them as part of a diet that
includes seal meat, which also carries detectable levels of
contaminants linked to health problems in higher doses.
Despite these chemicals, federal health officials say
the traditional diet is still healthier for the Inuit than the
alternative of processed southern foods. But climate change
could alter that equation.
Consider mercury, a highly toxic chemical that seeps
into the atmosphere in small doses from natural sources and is
pumped out in much larger amounts by smelters and coal-fired
powered plants.
Studies by federal meteorological scientists in the
1990s discovered what causes mercury transported from those
sources in the south to be drawn down from the Arctic skies
during spring precipitation.
On a surface of powdery snow, ultraviolet light from
the early sun, atmospheric ozone and bromine generated
naturally by algae and sea spray combine in what is known as a
mercury-depletion event.
Now, add climate change to that recipe.
Says Stern: "If warmer winters mean less multi-year ice
and more first-year ice, that should mean more light
transmission through the ice and a higher production of
under-ice algae.
"That could then bring more bromine."
And therefore a heavier mercury transfer into the water
where under certain conditions it changes into the highly
toxic and reactive form called methylmercury, which was
responsible for poisoning both fish and humans in Grassy
Narrows, Ont.
There are still more twists and turns in the saga of
mercury and Arctic climate change.
Stern and others involved with an ArcticNet research
consortium are investigating the prospect of a triple whammy
from rising average temperatures and reduced precipitation
that computer climate models project will be most severe in
the North:
 The
region of year-round permafrost is already shrinking.
Melting permafrost raises the prospect that atmospheric
mercury trapped there could be released.
The
Mackenzie River watershed has warmed at the rate of one degree
Celsius a decade since the 1970s. Warmer water probably will
encourage growth of the sulphur-reducing bacteria that are
pivotal in producing the dangerous methylmercury.
Over
the last 10 years, Canada has experienced forest fires of
unprecedented intensity and reach, resulting in the
atmospheric release of mercury.
Lower rainfall boosts the risk of forest fires, again
increasing the amount of mercury that could rain down on the
Arctic.
Mercury
contamination in western Arctic beluga whales today is four
times the level of two decades ago; whale-teeth studies found
only a ninefold increase over the past six centuries.
The whales might also be feeding in a part of the
Arctic Ocean where cod have higher mercury levels. Lisa
Loseto, a University of Manitoba zoology Ph.D. student working
with Stern, will investigate this possibility by fitting radio
collars to 10 beluga whales this summer.
"We want to find out if the whales are following the
receding sea ice," says Stern. "And is that because the cod
are also following the ice?"
Other researchers in the consortium are undertaking
detailed studies of the physical properties of the sea ice,
which in turn will help project how climate change might
affect ice cover over the entire Arctic.
And that ties back into the whole contaminants issue,
not only mercury but also the organochlorines for which the
Winnipeg labs will be looking 110 varieties of PCBs, six of
DDT and other insecticides like dieldrin, endosulfan and
toxaphene, which can occur in more than a dozen guises.
Add to all that the many unresolved questions about how
contaminants interact with plant and animal life in the water
column and you have a hint of the complexity of addressing the
climate-change question in the Arctic.
"Before this trip, I never really realized how
important zooplankton sh-- can be," sighs Stern, contemplating
the prospect of the tonnes of Arctic seawater that eventually
will turn up in Winnipeg.
Additional
articles by Peter Calamai
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