Covering nearly the same area as Norway, the
Hudson Bay Lowlands in northern Ontario and Manitoba is home to the
southernmost continuous expanse of permafrost in North America.
Compared with many marine waterways this far south, Hudson Bay
stays frozen late into the summer, its ice-covered surface
reflecting sunlight and keeping the surrounding area
cold.
The influence of Hudson Bay on the weather is
crazy, says Adam Kirkwood, a graduate student at Carleton
University in Ottawa, Ontario. It can be sunny and 20C one day in
August, and then half an hour later theres a wicked wind coming in
from the bay its 5C, and youre putting on all your layers, and
youre still freezing cold. And when its neither of those two
things, he says, its very, very buggy.
Trapped in all that permafrost is 30 billion
tonnes (33 billion US tons) of carbon. Its an unfathomable amount,
says Kirkwood. With global warming, the permafrost is thawing,
threatening to release a carbon bomb of heat-trapping methane gas
to the atmosphere. But theres something else lurking in the
permafrost, too. Something that has the potential to be more
immediately dangerous to the people and wildlife living in the
area: mercury.
Wildfires and volcanoes belch mercury and
since the Industrial Revolution so, too, do coal-burning power
plants and factories. Warm air currents carry mercury in its
inorganic heavy metal form to the Arctic where it settles into the
soil and vegetation before being safely locked away in the deeply
frozen permafrost.
In its inorganic form, mercury is less
threatening to people. But as the permafrost thaws, says Kirkwood,
mercury is finding its way into the soil and into the regions many
ponds, rivers, and lakes. Once there, microbes can convert
inorganic mercury into the form to be concerned about: neurotoxic
methylmercury.
For the Indigenous peoples of northern Ontario
who have lived off the peatlands for thousands of years hunting
caribou, catching fish, and gathering native plants the lurking
threat poses a risk to their way of life.
So for the past six years, Kirkwood has been
coming to this remote environment every summer, helicoptering in to
drill thick cores of peat and bringing them back to his lab for
analysis. On these trips, Kirkwood often has help from Sam Hunter,
a self-taught independent scientist from Peawanuck,
Ontario.
Back in the 1970s, Hunter saw how scientists
studying the Hudson Bay Lowlands used Indigenous peoples as guides,
but didnt involve them in their research. Now...