Posted by: Vicki Burns | October 1, 2015

Toxic Blue-Green Algae Blooms Growing in Size and Frequency throughout North America

I came across some news items in the last few days that confirm my sense that the threats of toxic blue-green algae blooms are increasing in many areas around North America. It seems important to ensure that the public understand this so that they will take the appropriate precautions if there are algae present. I’m often surprised by the comment I hear from various people “we’ve always had algae and there are historical reports documenting thick algae 200 years ago”. I usually respond that it was different species of algae, not the blue-green (cyanobacteria) that dominate now.

Blue-Green Algae sludge

Blue-Green Algae sludge

The first news item is from a few months ago but remains very timely and relevant. It is a study involving researchers from France, Italy, Spain, the UK, Malaysia, and across Canada.The title of the study is“Acceleration of cyanobacterial dominance in north temperate-subarctic lakes during the Anthropocene”, and it was published in the February issue of the online science journal Ecology Letters. It shows that cyanobacteria has been on the increase since 1900 but has grown much more rapidly since the 1950s. The researchers were able to look at core samples taken from the sediments of lakes going back 200 years. They surmise that the proliferation of cyanobacteria has flourished in part due to a warming climate as well as the addition of more nutrients, phosphorus and nitrogen, from sewage and crop fertilizers.
Another news item that caught my attention is about the huge toxic blue-green algae bloom that has overwhelmed the Ohio River in recent weeks. The bloom is now stretching 636 miles of the 981 mile long river. The only other toxic algae bloom recorded in this river was about 40 miles long and occurred in 2008. So this year’s occurrence is outstanding in a very alarming way.

Ohio River map, courtesy of

Ohio River map,

To reiterate my earlier comment, I hope that members of the public will understand that many of the algae blooms we are seeing in our North American lakes now,are composed of cyanobacteria, some of which contain harmful toxins. If we don’t acknowledge this as a real problem, there is less likelihood that we will make the changes and investments necessary to keep our lakes and rivers safe and clean. We can make a difference now to ensure our grandchildren have swimmable, drinkable, fishable lakes in their lifetimes.



  1. Thanks Vicki for your work……..Mo

    • Thanks Mo for your comments and for all you’ve done to heighten awareness of Lake Winnipeg issues.

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