One morning we had a flock of healthy Jacob sheep. The next morning half a dozen of them were dead. Their heads were thrown back, their limbs twisted. They had died in agony.
The horror that killed them and devastated us was a powerful toxin that has been identified in the lakes of every province in Canada. Although the highest concentrations are around the recreational waters of central Alberta and southern Manitoba, a new study published in the Canadian Journal of Fisheries and Aquatic Sciences shows no province has escaped it.
Cyanobacteria is what scientists call blue-green algae. Others just call it “pond scum.” The algae are not always blue-green. They can range from olive-green to red. The algae that killed our sheep had formed on a pond they relied on during summer’s heat.
Our algal bloom occurred only once in the nine years we were on the farm. (It was nowhere near as massive a bloom as you can see in the photo on the next page.) The combination of high temperatures, still water, and contamination from upstream waters helped create the perfect setting for an algal bloom. We were new to the property and not yet aware of the deadly combination.
Next: Climate Change and Toxic Water
In her Care2 post on the threat drought poses to drinking water and aquatic life, Jennifer Mueller pointed out that higher temperatures increase the buildup of cyanotoxins. As the climate warms, more lakes will experience algal and bacterial blooms. In addition, agricultural runoff and human development can lead to a buildup of the kinds of nutrients that lead to algal bloom.
The new study adds to our knowledge of “hotspots” or “hot times,” but more research is needed to determine how to manage stagnant lakes and reservoirs. Improving the handling of sewage and increasing vegetation around lakes can mitigate the problem. Farmers, ranchers and cottagers will all have to take responsibility for maintaining the health of lake waters.
As much as 30 to 50 percent of cyanobacterial blooms are harmless. Only a lab test can determine whether a particular bloom is toxic. If it is, as in our case, animals drinking the water suffer a horrible death. Children who drink or swim in it are likely to suffer liver damage. Adults may escape serious illness.
If the scientists’ predictions prove true, a lot more victims will fall ill and possibly die in the coming years. Water for humans and for livestock will be affected as this silent killer lurks in wait for its victims.
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Photo 1 from Wikimedia Commons; Photo 2: Thinkstock