Long a threat to southern Ontario lakes, climate change is allowing cyanobacteria -or blue-green algae- to thrive in even the coldest of the Great Lakes.
This photo essay was written and photographed by Chris McEvoy from The Narwhal.
The glassy waters of Hazelwood Lake, in northern Ontario, shatter as a plankton net crashes through the surface. Nathan Wilson, a doctoral candidate with Lakehead University’s environmental and biotechnology program, is attempting to fish out the nuances of cyanobacteria in the waters of northwestern Ontario.
More commonly referred to as blue-green algae — though it’s technically not algae, it’s bacteria — cyanobacteria’s presence is growing in Ontario lakes as the climate warms, including in the province’s north.
Generally, blooms result from a rise in nutrients, like nitrogen and phosphorus, in a body of water. This rise can be linked to inadequate septic systems, land and forestry developments and agricultural runoff. Warmer lakes make it easier for the blooms to proliferate, and Lake Superior is warming faster than most other Great Lakes.
As part of his research, Wilson wants to know just how healthy lakes in the region are, and a big part of that is understanding which bacteria live in the waters.
Though many algae blooms are harmless, some cyanobacteria species produce toxins that can affect not just the health of lakes, but people and animals, too. According to Health Canada, shortened exposure to these toxins can cause minor health problems like skin rashes and throat irritation, with continuous exposure causing severe illnesses like liver damage and potentially death.
The Lakehead Region Conservation Authority oversees the watershed that encompasses the Thunder Bay region, including four waterbodies: Hazelwood Lake, Mission Island Marsh, as well as Hurkett Cove and Silver Harbour on Lake Superior. Through its cyanobacteria management program, the authority has found the microscopic organism in all four waterbodies. And since 2022, the population of cyanobacteria has continued to thrive.
With algae blooms occurring at Thunder Bay’s shoreline on Lake Superior, there runs the risk of a broader presence of cyanobacteria in Canada’s largest freshwater lake, though Environment and Climate Change Canada told The Narwhal in an emailed statement “Lake Superior is not currently experiencing widespread, persistent blooms,” adding that targeted monitoring is still underway. That monitoring is a joint initiative between Canada, Ontario and U.S. federal and state agencies.
Beyond wanting to understand the frequency and impact of algae blooms, Wilson is concerned about the slow response to outbreaks. It can take days or weeks to detect, test and publicize toxic blooms around the northern shore of Lake Superior. And this assumes a sample of the bloom was ever taken, as they can migrate from their original reported location, making it tricky to capture.
If someone comes across what they think might be a bloom, they can contact Ontario’s Ministry of the Environment, Conservation and Parks to test it. If the test is positive, the Thunder Bay District Health Unit posts the location on its website. The challenge, as Wilson highlights, is by the time someone gets there to test the bloom, it might be gone, leading to false negatives. Postings of blue-green algae findings from previous years show it can take from a few days to more than a week from the time the sample is taken to when the test results are released — saying nothing of when the bloom was actually reported.
Neither the health unit or Environment Ministry responded to questions about how they manage and communicate testing for algae blooms.
According to the conservation authority, educating the public about the causes of harmful algae blooms is the first step in combating the issue — and it’s something they’re working on. Campers and property owners need to understand the importance of managing their septic systems properly to reduce pollution near water. Beyond education and understanding, monitoring programs need to continue.
Wilson also emphasizes that “community buy-in” is the key to addressing algae blooms in northwestern Ontario. If communities and the province invest their time and resources into the issue, he says, there should be a reduction in cyanobacteria blooms.
