As many Manitobans know, nothing spoils a trip to the lake like the algal blooms. New research has found the phosphorus that causes the problem can linger for years in the mud at the bottom lakes before being recirculated back into the water to further pollute the lake.
And researchers say Manitoba lakes are among the most susceptible to the problem.
“What our study was looking at was the process of recycling the phosphorus in the sediments back up into the water column so that phosphorus that we think should be locked away actually moves back up into the water column and can contribute to algal blooms,” explains University of Winnipeg assistant professor Nora Casson, who co-authored the study published in the Canadian Journal of Fisheries and Aquatic Sciences Wednesday.
“This is a problem because it means that phosphorus that’s coming in from the landscape isn’t just going to cause algal blooms today or that summer, it could result in poor water quality for years or decades to come.”
Algal blooms can have a negative effect on recreation activities, drinking water, property values and wildlife, and can put the health of both humans and animals at risk, says Casson.
Scientists have known since the 1970s that nutrient phosphorus causes the blue-green globs of muck. But even after regulations and improved sewage treatment went into effect to counteract the problem, the blooms continued to grow in lakes across the country.
That led scientists to look into whether phosphorus might be being recirculated back into the water, and the study released this week set out to better understand where, when, and why this process occurs in Canadian fresh waters.
For the study researchers reviewed data from 70 water bodies and found the recirculation of phosphorus — known as internal phosphorus loading — is a common phenomenon in Canadian fresh waters. But the rates of the process varied dramatically from lake to lake.
The researchers looked at data…