You want to understand more about cyanobacteria (also called blue green algae)?  We invite you to consult the following web sites :

The following link is an excellent portrait of cyanobacteria in Québec lakes.  You are invited to read it.
Portrait cyanobactéries du GRIL

Le site du Ministère du Développement durable et de l’Environnment:
www.mddep.gouv.qc.ca/eau/eco_aqua/cyanobacteries/index.htm

The Government of Canada web site :
http://www.hc-sc.gc.ca/ewh-semt/pubs/water-eau/cyanobacter-eng.php