Lake Winnipeg in Canada named world’s most-threatened lake by Global Nature Fund

Lake Winnipeg in Canada has been named the world's most-threatened lake by the Global Nature Fund.

Located in the Canadian province of Manitoba, Lake Winnipeg — Canada's third-biggest freshwater lake and the world's 10th-biggest lake — is under threat from agricultural run-off and sewage discharges which stimulate large amounts of blue-green algae, the Germany-based fund reports on its website.

CTV News wrote that algal blooms were toxic to humans and threw the lake's ecosystem off-balance. 

The Winnipeg Free Press quoted Vicki Burns, Outreach Coordinator for the Lake Winnipeg Foundation (LWF), as saying:

"Scientists have been warning us about Lake Winnipeg’s future as far back as 1969. They warned that we needed to decrease the nutrients that are causing the toxic blue-green algae blooms back then. Yet, despite these warnings the action to clean up the lake has been very slow."

The fund wrote that the lake's pollution was especially notable considering the relatively low population in the lake's watershed — about 7.0 inhabitants per square-kilometer across a million square kilometers stretching though Manitoba, Alberta, Saskatchewan, and the US states of North and South Dakota, Minnesota and Montana.

"The increasing frequency and severity of flooding associated with climate warming the drainage of wetlands, and the regulation of water levels are having further negative effects on the lake."

Udo Gattenjohner, from the Global Nature Fund, blamed "recent changes in Canadian polities" which "seem to be eroding the protection, particularly of vulnerable water ecosystems."

He added:

"It is disappointing because this does not really fit with our image of Canada."

Burns, meantime, said the deterioration in the quality of the lake could be "stymied, and ultimately, reversed."

Burns cited Lake Constance, bordered by Switzerland, Austria and Germany, as an example of a lake even more polluted than Lake Winnipeg which had been cleaned up so well that it now provided drinking water.