The great oxidation event

Blue green, blue green, blue green algae
The first free oxygen soaked up by iron
I breathe, I breathe, I breathe
Settled on the ocean floor
I breathe, I breathe, I breathe
Early form of live buried in the planet’s mantle
No fish, no birds, no complex life on earth
I breathe, I breathe, I breathe
Blue green, blue green, blue green algae
Tiny microbes populating the earth
Multiplying for reasons still unclear
Shaping, shaping, earth life, earth life