Canada's Subarctic Lakes are Drying Out
Atypically light snowfall over recent winters in Canada's subarctic regions has led many of the region's lakes to dry out, prompting researchers to worry.
After studying 70 lakes in and around Old Crow in the Yukon territory and Churchhill in Manitoba, researchers found that the majority of the lakes are less than 1 meter deep.
Analysis of the environment surrounding the lakes revealed that most lie on flat terrain surrounded by scrubby vegetation, which are also showing signs of desiccation, or dehydration.
Frédéric Bouchard, a postdoctoral fellow at Université Laval's Department of Geography and the Centre for Northern Studies, said the problem stemmed chiefly from a decline in meltwater.
From 2010 to 2012, for instance, average winter precipitation in Churchhill fell by 76 millimeters compared to the averages recorded between 1971 and 2000. Some of the most marked desiccation of lakes became apparent in the summer of 2013, which has ripple effects on the whole water system.
"With this type of lake, precipitation in the form of snow represents 30 percent to 50 percent of the annual water supply," said Bouchard, who is the lead author the research published in the journal Geophysical Research Letters.
Bouchard and his colleagues from Wilfrid Laurier University, Brock University and the University of Waterloo write that this level of desiccation in lakes in without precedent in the last two centuries.
"Isotopic analyses conducted on the remains of phytoplankton accumulated in lakebed sediment show that the lakes have maintained water balance for 200 years. This stability was abruptly disrupted a few years ago," the research team said in a statement.
If the trend of dry summers and less heavy snowfall continues in the region, the researchers think many of the region's shallower subarctic lakes could dry out completely.
"It's difficult to predict all the repercussions of this habitat loss," Bouchard said, "but it's certain that the ecological consequences will be significant."