Climate change causing lakes in Canadian Rockies to lose their famous turquoise lustre, says ecologist

New research from the University of Alberta says the Canadian Rockies may be losing one of their most iconic features — those brilliant turquoise alpine lakes.

"This summer the heat domes in Western Canada really have accelerated the rate of melting of the glaciers in the … Rockies," said professor of aquatic ecology Rolf Vinebrooke on CBC Radio's Daybreak South Tuesday.

Vinebrooke explained that the lakes contain glacial flour, a sediment from rocks that slowly makes its way into the water through erosion. But as the glaciers melt at faster rates than ever before, less of the meltwater contains the rock flour, which intercepts sunlight and gives the lakes their milky turquoise luster. 

He said this could also cause the water quality to deteriorate and harm unique species that live in the lakes.

"I don't think it's really been in peoples' attention until this summer when it really was something profound," Vinebrooke noted, referring to the noticeable lack of turquoise in the water.

Vinebrooke said nitrogen-rich rainfall from recent air pollution, along with notable amounts of phosphorus found in wildfire ash have also contributed to turning the water green, rather than blue, as these chemicals encourage plant growth. 

The research comes after a 2020 study that found similar results, particularly around Zigadenus Lake, northeast of Lake Louise.

Another study from 2018  predicted 80 per cent of mountain glaciers in Western Canada will disappear in the next 50 years.

'Disappearing lustre could harm aquatic species'

Vinebrooke said that while turbid alpine lakes fed by glaciers are "not that well-studied or documented ecologically or biologically," they have become unique environments for a number of endemic species since the glaciers retreated 12,000 years ago — species that could lose their habitats with the increase in light exposure. 

"The health is changing," he said. "These alpine sites are relatively clean and pristine ... [but] we might start seeing things that haven't happened yet, [like] blue-green algae forming."

He said that alpine systems can be very sensitive to larger atmospheric changes, like global warming, and that once the glaciers shrink "to a certain small size, they're not going to return any time soon."

Vinebrooke's research laboratory has been documenting the "clarification" of alpine lakes near Banff and Jasper by taking core samples from the lake bottoms and using archival photos. 

The most prominent examples of the phenomenon, he said, can be found in the Geraldine Lakes west of the Icefields Parkway, McConnell Lake near Banff, and Curator Lake in Jasper National Park.

Vinebrooke said if humans are successful in controlling greenhouse gas emissions in the near future, some of the larger glaciers may remain in place. 

"But that's going to take a lot of effort on our part because this is probably the most difficult environmental issue that humans have faced so far."

LISTEN | Rolf Vinebrooke explains the changing colour of lakes in the Canadian Rockies, on CBC Radio's Daybreak South.