Cyanobacteria are a very old life form. About three billion years ago, cyanobacteria started supplying the atmosphere with oxygen through photosynthesis – an atmosphere which, up until that point, had mainly consisted of carbon dioxide, nitrogen and water vapour. Without this oxygen, life as we know it today could never have developed.
Cyanobacteria are a very old life form. About three billion years ago, cyanobacteria started supplying the atmosphere with oxygen through photosynthesis – an atmosphere which, up until that point, had mainly consisted of carbon dioxide, nitrogen and water vapour. Without this oxygen, life as we know it today could never have developed.
Blue-green algae
Because cyanobacteria, such as green algae, use the sun's energy to produce nutrients, they are also sometimes referred to as blue-green algae. The blue-green colour comes from the two different types of pigment they use to absorb light energy: a blue pigment and a green pigment. There are also some species with red and yellow pigments, or with just one pigment.
Do not swim
During hot summers, the numbers of blue-green algae can increase dramatically in ditches and lakes. The annoying thing about this ‘algal blooms’ is that some produce toxins which are hazardous to people and animals. You can become ill if you swallow the water. The 'algal blooms' makes the water therefore temporarily unsuitable for swimming.