As glorious as Alberta summers can be, they come with their own set of problems, like blue-green algae. Unfortunately for eager campers and swimmers, the blooms — which happen every year — can effectively shut down lakes. So, what exactly is blue-green algae? Blue-green algae or cyanobacteria forms in slow-moving, shallow waters and is usually the result of an excess of nitrogen and phosphorus. These nutrients are essential for plant growth, but big blooms of the bacteria are largely caused by human activity like agriculture or residential development.