- A bloom is an exuberant increase in the number of cyanobacteria cells that negatively affects water quality. Blooms tend to float to the surface and may look like pond scum or cause the water to have an oily, paint-like appearance.
- Ideal conditions for a cyanobacteria bloom are warm, slow-moving waters, sunny days and high levels of phosphorus and nitrogen. However, various species have made adaptations to compensate for adverse conditions.
- Some species of cyanobacteria produce akinetes, which are thick-walled spore-like cells. These cells contain reserve materials that will allow the species to "seed" an area and survive until conditions improve. In addition, various species have developed resistances to a great range of temperatures, light availability and salinity.
- The growth rate of cyanobacteria is much slower than multicellular algae varieties. Therefore, blooms typically only occur in water with long retention times, such as lakes and ponds. Despite the slow growth rate of cyanobacteria, it can often overtake other types of algae because of adaptations that make it highly capable of out-competing those populations.
- Cyanobacteria naturally spread through connected waterways. Humans contribute to the spread by carrying cyanobacteria on boats and bait buckets.
- Though cyanobacteria are a mainly aquatic life form, they have been found on damp surfaces such as terracotta pots and trees, as well as clinging to polar bear fur in the Arctic.
