Ice-Covered Arctic Lakes May Harbor Signs of Climate Change
Arctic coastal environments are some of the most vulnerable
to climate change. A team of WHOI researchers visited Canada’s
Mackenzie River Delta in April 2007 to find out just how vulnerable. Marine
geochemists Tim Eglinton, Daniel Montluçon, and Angie Dickens, and geologist
Liviu Giosan trekked into the frozen wilderness to drill through ice and water
and into the sediments on the bottoms of lakes within the delta. Each spring,
as the Canadian interior thaws and snow melts, a sediment-laden pulse of melt
water surges down the streams and rivers, inundating the delta, flooding river
banks, and filling the numerous low-lying lakes. The sediments that settle to
the bottom comprise old carbon (derived from plants, microbes, and animals)
that has been sequestered for many years in Arctic soils within the watershed.
These sediments can tell the history of past river flows and floods up to the
globally warming present. This spring, Eglinton and colleagues collected
sediment cores stretching back for at least 1,000 years, and they hope to decipher
how the discharge of the river has changed. The increasing flow into the
ice-capped lakes of the Mackenzie Delta is a clear sign of increased melting in
the Arctic; it may also suggest that more organic carbon
will be released from the Arctic permafrost soils and back into the ocean and
atmosphere. This year’s expedition was launched to prove that researchers could
recover useful data from the delta. Eglinton is now planning to return in 2008
for more extensive sampling.
Related Links
» Links between Climate Change, Permafrost Stability, and Terrestrial Organic Carbon Export from the Mackenzie River
» Follow the Carbon Trail from Oceanus magazine
» The Once and Future Danube Delta from Oceanus magazine