When you head to a lake in Canada this summer, you may notice more algae covering the surface than usual. It’s just one of the dire impacts our warming planet is having on lakes worldwide right now, according to a biology professor.
It’s part of a pattern that will only intensify with global warming, John Small, a professor at Queen’s University, told CTV News Channel, painting a picture of lakes shrinking, others flooding, fish species disappearing and algal blooms killing underwater plants.
“We are sleepwalking toward disaster,” he said Sunday, saying we must act now to slow those changes. “I wouldn’t say it’s too, too late, but it’s very, very late.”
When people initially hear that our summers are getting longer, at first “they think it’s great,” he said.
But with this continued warmth comes increasing instability in ecosystems, including the more than 100 million lakes that exist in the world.
“One of the classic things for people who might be at their cottages this weekend or soon, they’re going to start seeing probably more algal blooms, especially blue-green algal blooms — that’s the scum on the surface of the lakes,” Small said. “They probably haven’t seen those that they normally have in the past.”
He explained that blue-green algal blooms, which are cyanobacterial blooms, “can have serious health consequences not only for us, but also for other organisms.”
Cyanobacteria thrive in warm water and can grow faster when temperatures rise, meaning climate change could help provide the perfect conditions for increased algal blooms.
These algal blooms can block sunlight for those living below the water’s surface, as well as consume oxygen that could otherwise feed underwater plants, leading to dead zones in our lakes. They can even make the water toxic by giving off too much oxygen.
We’ve seen the impact of cyanobacterial blooms before in one of the Great Lakes—the water supply in Toldeo, Ohio, was shut down for three days in 2014 due to an algal bloom in Lake Erie.
But how climate change is affecting our lakes goes beyond algae.
“It’s just one of those things you can see visually,” Small said. “Many fish habitats are severely affected, especially for deep-sea fish that like cold water.”
Increased algal blooms, cold-water fish losing their natural habitats, shrinking winter ice cover and declining levels of dissolved oxygen in the water are covered in a new study that looks at how climate change is affecting lakes.
Small, along with experts from the University of York and Bangor University in Wales, reviewed current research on freshwater lakes from around the world to create a cohesive picture.
The report, published in mid-July in the peer-reviewed journal BioScience, found that climate change is transforming our lakes in many ways, depending on where on the planet they are.
In Ontario, algal blooms have been reported in lakes as late as November, the study said.
The study also found that global lake evaporation is expected to increase by 16 percent by the end of the century.
“In an area with more evaporation, water levels will drop,” Small said. “If you’re in an area that’s getting more runoff now, say you’re getting your water from high mountain areas that are driven by glacial melt, well, right now you might be getting a lot of water, even too much water.
“They’re like water towers, these glaciers in the mountains — once they melt, they kind of slow down and cut off a lot of the water supply.”
The loss of ice cover on lakes can also lead to greater salinity in the water itself, the study found, affecting aquatic life.
Small said the various impacts climate change is having on our lakes affect not only the plants and animals in the water, but also the cultural, recreational and economic activities of the people who live by that water.
“For many people, freshwater fish is a major source of protein, not just in Canada but around the world, and if some of your prized fish are pushed out by this warming, that affects food security,” he said.
These impacts are often felt more strongly by local communities who may rely on fishing and other water-related activities.
“The last thing many indigenous communities need is more problems with their water supply,” Small said.
Our inaction on climate change is disappointing to scientists like Small, who said we haven’t prepared enough for how our world is changing.
“The fact that I’m still mad means I still have hope,” he said. “But it is very, very late.
“There are several positive things that are being supported by various governments, but we need to move quickly and get in that direction. The longer we wait, the fewer options we have. And indeed, now, options for our grandchildren and great-grandchildren. More changes are coming and we need to prepare for them.”
Add Comment