How do blue-green algae reproduce?

Blue-green algae (also called cyanobacteria) are a type of bacteria found in many lakes, water bodies, and reservoirs. These bacteria can multiply a lot in the summer, causing extensive growth called bloom. Algae often form when conditions are calm and look like scum on the surface of the water. Algae can be blue-green or greenish brown and often smell musty or herbaceous. Some blooming types of blue-green algae produce toxins.