Many people think that the Amazon is the lungs of the world. It’s actually just a piece of a much bigger cycle.
The fact is that most of the oxygen produced on the planet comes from a being called diatom, which is a kind of microscopic plankton and exists by the billions in the ocean.
Watch the episode of the new Netflix series “one strange rock” where he talks about oxygen and diatoms. Or just Google that term and you’ll understand how the great oxygen cycle works (which isn’t what you were told at school).