It’s blue-green algae! In a lake, it may look like broccoli soup, but you certainly don’t want to ingest it.

When blue-green algae – known scientifically as cyanobacteria – begin to proliferate (or bloom) in a body of water, the problem can quickly become a nightmare for city officials. Invisible to the naked eye, these tiny single-cell organisms have the annoying habit of producing, under certain conditions, toxins – called cyanotoxins – that build up in water. In large quantities, blue-green algae blooms can be dangerous: they can cause intoxications or death if ingested or skin problems when swimming in water where they are present. They are a threat to humans, but also to livestock, fish and wildlife.

“But it’s not always the case, since not all cyanobacteria are created equal,” explains Sébastien Sauvé. “The term refers to approximately one hundred different strains with varying levels of toxicity. Half of them are still relatively unknown. “

Sébastien Sauvé, a professor of environmental analytical chemistry at Université de Montréal, knows these little organisms well. He is the lead investigator of ATRAPP (Algal Blooms, Treatment, Risk Assessment, Prediction and Prevention Through Genomics), a research initiative focused on better understanding cyanobacteria, their identification and their modes of reproduction. 

Cyanobacteria live in all bodies of water around the world in concentrations that are generally too low to cause problems. When they start to proliferate at a rapid pace, however, they create a greenish scum on the surface of the water (hence its name). This can occur when water temperatures rise and/or phosphate levels from agriculture or poorly treated wastewater increase, creating the perfect breeding ground for cyanobacteria. Water with over 20,000 cyanobacteria per millilitre is considered unfit for human consumption.

But when there’s a bloom, how can we tell which cyanobacteria are involved? At the moment, we can’t. When in doubt, city officials generally do not take any chances and bring out the heavy artillery: no swimming, no drinking, alternate water supply, very expensive processes to treat the drinking water. These measures come with a hefty price tag. In the United States alone, problems due to cyanobacteria cost $825 million annually.

ATRAPP will provide city officials with solutions. Researchers are looking to trace the genetic code of cyanobacteria in order to document their specific features. Which genes are correlated with the production of toxins? How are they expressed before and during blooms? Under what conditions?

The results will help researchers determine new biological markers – or ID cards – to quickly test water and identify the strain or strains of cyanobacteria involved. Ultimately, they hope to provide cities with a chemistry and genomics toolkit that can rapidly determine the risks of toxicity and facilitate the prevention of treatment of harmful algal blooms.

Concretely, this would mean being able to take a sample, run a test and, within a few hours, know exactly which strain of algae is present and be able to decide whether or not major treatment measures are warranted.

In the long run, ATRAPP will also propose new cost-effective ways to intervene when blooms occur and affordable long-term prevention measures, since in life, as with algae, prevention is worth a pound of cure.


To visit ATRAPP’s website (in French only)