Sudbury professor offers tips to slow the growth of blue-green algae

A Sudbury professor says although blue-green algae or cyanobacteria is always in our lakes the public can take steps to reduce how much is present.

Recently within a week, four cases of blue-green were reported in Sudbury lakes.

Charles Ramcharan, a professor at Laurentian University in the School of the Environment, says for blue-green algae to thrive, it needs two things: warm weather and lots of nutrients.

"So when you have hot and dry, you have the warm conditions that they like but you don't have the nutrients because nothing is getting washed into the waterways," he said.

"But what you do have is a set-up for a big bloom because once the rains come back and that stuff gets washed into the waterways, the water is already hot so you have perfect conditions."

He adds cyanobacteria is always present in the water.

"We give them an advantage by providing them with nutrients that they have difficulty obtaining themselves," he said.

"So if we oversupply those nutrients, in particular phosphorus, we give them a competitive advantage over all the other species out there."

So what can people do to cut down on the amount of nutrients going into the lakes? Ramcharan says fertilizers are a big source, but adds there are other nutrients being provided to encourage the growth of blue-green algae, including those from septic systems.

"The leakage from your septic system will be entering the waterways and that's a large source of phosphorus as well," he said.

Water with blue-green algae in it shouldn't be used for drinking or swimming, but Ramcharan says there's more issues with having it in area lakes.

"For the aquatic food webs, this a food source that's difficult for a lot of animals to eat … it's not terribly nutritious and it can be toxic," he said.

"For people, at minimum, it's an aesthetic issue. It looks funny and it smells bad and it can be an irritant on skin."