Climate Change in the Arctic - The Changing Arctic Environment: The Arctic Messenger - page 310

intolerant to the low-salinity surface water that has been accumulating there over the last
decade. Ringed seals birth and nurse their pups in snow caves they build on continuous sea
ice and from which they exploit the marine foods associated with the ice and the ice edge.
These marine foods include Arctic cod. Bearded seals, a benthic (bottom-feeding) species,
birth and nurse their pups on shallow water pack ice. Both species also use the ice for long
periods during moulting. They are (particularly the ringed seal) the polar bear's primary
prey. The long-term outlook for all three species suggests a risk of extinction. Polar bear
populations insomeareasarealreadyshowingsignsofmalnutrition. Remember thatunlike
the omnivorous grizzly and brown bears, the polar bear is exclusively carnivorous. It has
no opportunity for adaptation to a marine life without ice. There are 19 subpopulations of
polar bear, seven of which are in decline. The results of two studies linked subpopulation
decline (survival) to changes in the seasonal availability of sea ice (western Hudson Bay
and southern Beaufort Sea populations).
The walrus is a large benthic-feeding marine mammal. By drifting with the moving
pack ice edge, it has historically avoided overgrazing its feeding grounds. In response to
the ice edge no longer being over shallow waters, some populations settle on rocky islands
or headlands and are already tending to deplete their summer food supply. Seals and walrus
provide a very large proportion of the total diet of Inuit communities. Like most indigen-
ous peoples who maintain a traditional way of life, there is no acceptable replacement for
these foods because their entire culture is based on them. They are (as already noted in the
chapter on POPs and heavy metals) also much more healthy to eat than store-bought foods
available in northern towns or settlements. A dietary transition to store-bought foods also
imposes economic stress in many Arctic communities.
Finally, we have already examined in the POPs and heavy metals chapter how climate
warming is already beginning to remobilize certain toxic, semivolatile pollutants, which
had previously been immobilized in Arctic soil, sediments, snow and ice. Once remobil-
ized, they then become available for biological uptake and have the potential to lead to
wildlife and human health implications.