Warm weather in late summer and early fall creates the perfect conditions for toxic algae to grow and bloom.
According to researchers at the University of Guelph, the explosive growth of algal blooms in recent years is linked to rising temperatures.
"Hazardous algal blooms are starting earlier each year and lasting longer into the fall," says University of Guelph aquatic toxicologist, René Shahmohamadloo.
"Summers are getting warmer and longer. The windows are shortening with longer falls and shorter winters in Ontario, as well as earlier springs. Harmful algal blooms love that because it gives them an early start to expanding."
Blue-green algae has been observed at Grand River Conservation Area properties including Belwood Lake, Conestogo Lake, Guelph Lake and Woolwich reservoirs.
Some varieties can produce toxins that are harmful to people, aquatic life and can often be fatal to pets.
"Children, elderly, or pregnant women or more susceptible and are categorized as sensitive populations. We need to be mindful of that," Shahmohamadloo said.
“It is crucial to avoid contact with blooms because their toxicity is often difficult to determine without testing. Ingestion, inhalation, or skin contact with contaminated water can potentially lead to health issues."
To prevent health concerns from algae blooms, Shahmohamadloo recommends, avoiding direct contact with the water, not swimming or wading in water with blooms present, and consulting provincial fish consumption advisories when eating fish caught in areas affected by blooms.
Avoid contaminated water for drinking, cooking or bathing, rinse any exposed skin immediately, and seek medical attention for symptoms like skin irritation, nausea or respiratory issues.
Shahmohamadloo, a postdoctoral fellow in the Department of Integrative Biology, says Ontario approached record high temperatures in September, and warmer-than-normal weather continued into October.
Ongoing agricultural practices can also contribute to excess nutrients in bodies of fresh water, resulting in an overgrowth of algae.
“In recent years, we’ve observed blooms in colder and nutrient-poor lakes, which is an unexpected shift indicating that hazardous algae can adapt to a broader range of environments,” Shahmohamadloo said.
Blue-green algae thrive on nutrients from fields and lawns that find their way into local waterways and reservoirs during heavy rainfall or spring melts. This causes their populations to grow rapidly, and to form blooms or scum on the surface of the water.
"Sometimes if there are farming operations close to our fresh waters, nutrients like nitrogen and phosphorus can run off into the water. These are the nuts and bolts of how the algal blooms can thrive and expand," Shahmohamadloo said.
But, climate is not the only component.
"A combination of factors can allow the bacteria to outcompete other sources of healthy algae. And then, year after year, you will see that combination of species in those waters," Shahmohamadloo said.
Different species of algal blooms produce different toxins.
One is anatoxin, which Shahmohamadloo says, works very quickly. If it gets ingested, by dogs for example, it could be lethal and even cause death.
"I like to give this advice from a chief scientist from the World Health Organization who mentioned that if you dip your feet in the water and you can't see your toes, maybe you don't want to be swimming in it."
There are also other more commonly produced toxins like microcystins.
"These are liver toxins that don't necessarily kill you, but at a sufficient dose, it can be lethal and cause liver failure," Shahmohamadloo said.
"But if we are trying to protect our waters, what about the fish that we consume? They a voiceless population, but who's advocating for the fish?"
Advice from the Ontario Ministry of the Environment, Conservation and Parks promotes that people should always cut out the fillet before consuming fish, and to not cook fish whole.
"The reason being if these toxins accumulate in the liver or kidneys, and you cook the fish whole, there's always an opportunity that during that cooking process, the toxin could leak out and go into other areas. This toxin can withstand cooking and boiling," Shahmohamadloo said.
Shahmohamadloo's post-doctoral research is focused on developing a genetic screening tool to monitor blue-green algae in Ontario’s lakes.
"In terms of research, there are different approaches including AI technologies and remote sensing, for example, being able to detect blooms as they happen. That's a great approach in giving us early warning signals," he said.
"Another approach is using genomics. Like human beings, there is a lot of diversity."
Genomics is the study of the complete set of genes (the genome) of organisms, of the way genes work, interact with each other and with the environment.
"So, there is active research to try and understand this genetic diversity," Shahmohamadloo said.
"The hope is to develop genomic tools so that we can then work with government and local authorities to deploy them and work toward an early monitoring system."