Sun seekers at Manitoba's Grand Beach got an unpleasant surprise last weekend as blue-green algae slime coated parts of the world-famous beach area.
Al Kristofferson of the Lake Winnipeg Research Consortium said algae blooms form annually in the north basin of Lake Winnipeg due to its high nutrient content. And blooms in the south basin such as the one that washed up on Grand Beach happen sporadically.
Kristofferson warned swimmers that the algae can contain harmful bacteria.
"The problem is you never know when they're releasing the toxins, so if you see the bloom in the water, don't go in the water. Don't let your kids go in the water, don't let your pets go in the water."
Kristofferson said while awareness of the harmful impact of nutrient contamination on the lake is growing, there is no evidence current levels are declining.
But because the algae blooms only show up on certain years in the south basin of Lake Winnipeg, he said people may be fooled into thinking the problem is getting better.