Why do blue-green algae blooms occur?
Blue-green algae are well adapted to growth and persistence in nutrient-rich lakes, reservoirs and ponds. They out-compete algae for optimal levels of sunlight and nutrients, in part, by regulating their buoyancy in the water. Blue-green algae cells have the ability to form gas-filled cavities, which enable them to move vertically through the water column to access optimal levels of light and nutrients. They also use their buoyancy to counter the downward drag of wind currents. The cells can become over-buoyant and concentrate near the water’s surface when calm conditions follow windy periods. These surface accumulations intensify if waves carry the blue-green algae along the shorelines and beaches. The results are blue-green algae blooms that make the water look like pea soup.
