The lungs of the Earth: or so we thought

Elissa Dames , Editor in Chief

As headlines filled the internet about the forest fires in the Amazon, a fear broke out across the world that the supplier of twenty percent of our oxygen was on the brink of disappearance. Many news channels, politicians, celebrities and environmentalists are claiming that Earth’s oxygen supply is in jeopardy. 

The claim seems to make sense because the Amazon’s landmass is so large. It would take 27.4 Nebraska’s to fill the 2.124 million square mile forest. 

However, is it true that the Amazon is responsible for that much oxygen? Many scientists sought out the answer by conducting experiments to see if the statement was true. However, it was proven to be false.

“The claim just doesn’t make any physical sense,” Michael Coe, director of the Amazon program at the Woods Hole Research Center said in an interview with National Geographic.

There just is not enough carbon dioxide in Earth’s atmosphere for trees to photosynthesize twenty percent of Earth’s oxygen. Every tree absorbs a certain amount of carbon dioxide. In return, they release an almost equal about of oxygen. Earth’s atmosphere contains less than half a percent of carbon dioxide, making it impossible for the Amazon rainforest to generate that much oxygen. 

So where did we go wrong? The catch is that trees do not just exhale oxygen, but also inhale it through a process called cellular respiration. During this process, trees convert the sugars they get during the day into energy, using oxygen that they’ve released to power the process. For photosynthesis to occur, the sun needs to be out. So during the night, trees absorb oxygen. Yadvinder Mahli, an ecosystem ecologist at Oxford University’s Environmental Change Institute, and his research team believe trees take back in over half of the oxygen they produce during cellular respiration. 

So, if the majority of Earth’s oxygen does not come from the Amazon, where does it come from? It comes from tiny, microscopic plants called phytoplankton. Phytoplankton are one-celled plants that live near the surface of the ocean. Through the sun and nutrients from the water, phytoplankton can go through photosynthesis and generate oxygen. 

“The net [oxygen] effect of the Amazon, or any other biome, is around zero,” Mahli said.

There are many reasons to keep the Amazon rainforest alive. However, oxygen justs is not one of them.