Posted by: Vicki Burns | October 15, 2015

Climate Change, Lake Winnipeg and Blue-Green Algae

Floods on Red River , compiled by Manitoba Conservation and Water Stewardship

Floods on Red River , compiled by Manitoba Conservation and Water Stewardship

Over the past year, we are hearing the term “climate change” used much more frequently in main stream media, usually in relation to big storms including typhoons, hurricanes, wind, rain and snow storms. But the concrete effect of climate change on our lakes has not been described often.
I first became aware of the very real effects already being observed when I read the Lake of the Woods Water Sustainability Foundation’s Phosphorus Budget Studies report in 2011. I was amazed to learn that on average the Lake of the Woods has 28 more ice free days each year than it had in the 1960s.In essence this means the lake may be thawing 2 weeks earlier in the spring and freezing 2 weeks later in the fall. This provides almost a whole month longer of growing season for algae, much of which is blue-green algae(cyanobacteria).
Information on the number of ice-free days on Lake Winnipeg is not readily available but Manitoba Hydro has prepared a comprehensive report that looks at historical and future climate predictions for the Lake Winnipeg Watershed. It is very illuminating to see some of the already evident changes in normal air temperatures in communities close to the lake. In Gimli, the mean annual temperature from 1971 to 2000 was 1.8 but in 6 of the 9 years between 1999 to 2007 that mean was exceeded.
The increase in major storm events in the Lake Winnipeg Watershed is resulting in more flooding which exacerbates the problem of blue-green algae because of the excess of phosphorus and nitrogen that is pulled off the land. In Manitoba over the past 60 years we have experienced floods in 1950, 1997, 2009 and 2011 which caused substantial damage, especially along the Red River and Assiniboine River basins. As well the weather bomb that hit Lake Winnipeg in October 2010 caused tremendous damage due to erosion and flooding.

Algae Winnipeg River Oct. 9, 2015

Algae on Winnipeg River Oct. 9, 2015

This article about lakes in Nebraska caught my attention because it highlights the persistence of toxic algal blooms in 4 lakes in that state well into the fall season. Normally they would have been gone weeks ago but because of warm weather they lasted into October. According to Dr. Ali Kahn, dean of the School of Public Health at the University of Nebraska Medical Center. “You get increased algal blooms. You get increased marine toxins that in turn make their way into your food supply.” He is warning that humans are already experiencing negative health effects from a warming climate.
So to sum up, Lake Winnipeg and other lakes throughout North America are showing the effects of a warming climate, the proliferation of blue-green algae being one of the most visible signs.Bold, timely and substantial action is needed now to decrease the degradation of our lakes.


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