WHERE DOES ALL THE OXYGEN? land the secrets of the earth

                                   5. WHERE DOES ALL THE OXYGEN?





We humans owe our existence to microscopic creatures, cyanobacteria, which have helped to radically transform the Earth's atmosphere. They pumped out oxygen as waste, filling the skies for the first time about 2.4 billion years ago. But the rocks reveal that the oxygen levels were going up and down like a roller coaster for 3,000 million years, until it stabilized around the Cambrian period about 541 million years ago. So, the peak air depended exclusively by bacteria, or there was another factor that contributed? Understanding the transition to a land rich in oxygen is a key to decode the history of life on our planet