Early Oxygen Producers

Early Oxygen Producers

One waste product of photosynthesis is free oxygen and as early forms of life started to photosynthesize, oxygen was released into the atmosphere. This made possible the evolution of more complex creatures that need oxygen to get energy from their food. Blue-green algae were some of the very early forms of life and today's species can still grow in extreme conditions, from hot springs to the Arctic icepack. Some species absorb or "fix" nitrogen from the air, forming nitrates in the soil for plants to use. Cyanophytes can reduce the need for nitrate fertilisers in places like rice paddies. [CH] {EN}