Global climate change could be behind the rise in blue-green algae blooms across northern Ontario, at least according to a renowned Canadian ecosystem scientist.

"We're trying to figure out what triggers the cyanobacteria blooms in landscapes that are historically not known to have had these...blooms," says Irena Creed, the executive director of the School of Environment and Sustainable Development at the University of Saskatchewan.

She was in Sudbury, Ont., on Friday for Laurentian University's annual watershed lecture.

Creed spoke to a group of environmental scientists, biologists and community members about her research into cyanobacteria, the scientific name for the algae blooms.

"There's so many interacting effects of all of those global change drivers, that it becomes hard to tease apart what may be contributing to the rise — and it's globally a rise — in cyanobacterial blooms," Creed says.

The Sudbury and District Health Unit confirmed on Wednesday that Wanapitei Lake and Clearwater Lake in Sudbury both tested positive for blue-green algae. Several lakes in the area tested positive for the algae throughout the summer.

Temperature, precipitation and forests all a factor

Irena Creed, an ecosystems scientist from the University of Saskatchewan, says understanding what causes blue-green algae blooms can help us predict the impact on humans. (Robin De Angelis/CBC) To track the presence of algae blooms over time, Creed says her research team used satellite images to build a 30-year timeline of over 20,000 lakes. Graduate students also gathered samples from the lakes for testing.

"We're looking at the interactive effects of warmer temperatures, changing precipitation patterns, more intense storms, and how that changes the supply of nutrients from the land to the water."

Creed notes that Ontario is almost 85 per cent forested, meaning that what is happening in the forest can also have a big effect on what is going on in the lakes. As temperatures increase, the type of trees and length of the growing season is changing.

"The combination of those two factors means that later in the fall, you're having a fresh supply of nutrients that's hitting that forest floor, that could then be driving a next wave of algal blooms in the lakes."

Creed says understanding the conditions under which blue-green algae is produced is the key to predicting how humans might be affected. Toxins in cyanobacteria have been linked to neurological conditions, including Amyotrophic Lateral Sclerosis (ALS) and Alzheimer's disease.

"If we learn from that, we might be at least able to identify the risk of many of the human settlements around these lakes," Creed says.

"When is there the likelihood that there might be toxins in those lakes?"