As glaciers retreat and disappear due to climate change, turquoise lakes like those seen in the Canadian Rockies will become clearer, impacting aquatic life.
They will look like the lakes we see in central Alberta, says Rolf Vinebrooke, a freshwater ecologist at the University of Alberta.
He notes that this change is already underway and that some lakes are becoming increasingly sapphire blue. For example, Lakes Curator and Geraldine in Jasper National Park are already clearer. The turquoise color we find is the result of glacial flour or tiny sediments that come from the rocks and slowly enter the lakes through erosion.
While one might think that the loss of these residues represents something harmful, experts point to the likely benefits for aquatic life. When lakes become clearer, sunlight can penetrate deeper into the water, which promotes algae growth. The retreat of glacial ice therefore leads to warmer water, making the lakes more productive.
One unique species that could be threatened, however, is a bright red copepod called Hesperodiaptomus arcticus, a crustacean about the size of a feather’s tip.
According to Janet Fischer, a biology professor at Franklin and Marshall College in Pennsylvania, warming lake environments could make the lake environment more conducive to supporting different species. The most widespread species could then invade the lakes and compete with unique species such as Hesperodiaptomus arcticus.
With her husband Mark Olson, she has been studying and documenting the color of lakes in the Canadian Rocky Mountains for 18 years. I think these lakes are beautiful at all stages of their development, but there’s a certain sadness when you’ve spent your life documenting a change that humans have accelerated, she says. The lakes will remain beautiful, but they will be different.
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Melting glaciers are changing the color of lakes in the Canadian Rockies, in some cases from turquoise to sapphire blue. (archive photo)
Photo: Provided by Clark Monson
What does this mean for fish?
Melting glaciers create waterways that were previously hidden beneath layers of ice. Therefore, warmer water without glacier flour results in a more productive lake, meaning more food is available for fish.
Some areas could become more productive in the future, says Matthew Sloat, scientific director of the international organization Wild Salmon Center.
He adds that in British Columbia, retreating glaciers are providing more habitat for cold-water fish, particularly salmon. However, climate change continues to pose problems for aquatic life, particularly as some rivers risk drying up in summer as glaciers disappear.
Even if there is more habitat, fish need to be able to access it. However, this can be problematic if a huge waterfall is an obstacle. Another problem arises when the lakes change color and warm up too quickly.
It really depends on the scale of the phenomenon. If this happens very quickly, the ecosystem may not adapt as easily, says Rolf Vinebrooke of the University of Alberta. You don’t really know what you’ve lost until it’s gone.
With information from Liam Merriam