Often you can find a statement according to which dense vegetation in the pool of one of the largest world rivers is responsible for the fifth of all oxygen existing on our planet. We checked whether these figures are correct.

In August 2019, during the next series of forest fires in the north of South America, French President Emmanuel Macron posted a warning in his microblog tweet: “Our house is burning. Literally. Amazon rain forests are lungs, which produce about 20% oxygen on our planet - in fire. "

A similar statement can be found in Russian -speaking ("Radio Liberty","Gazeta.ru" Life), and in the English -speaking (CNN, ABC News, Sky News) sources. Among celebrities who distributed it, one can also distinguish the future vice president of the United States Kamalu Harris And a football player Cristiano Ronaldo.

Light planets rain forests in the pool of the Amazons are called enough for a long time, and this is not a formal mistake - indeed, this is the world's largest tropical forest (5.5 million km²), covering the territory of nine states. However, what is 20% of all oxygen on Earth? This is a fifth of the entire accumulation of this element in the atmosphere, that is, a huge volume, given that its concentration to people Enough For breathing to about 9 km, and a small amount can be found up to a height of 115 km.

A key role in this process is occupied by photosynthesis. And indeed, according to researchconducted by a prominent ecologist, director of the Non -profit organization Project Drawdown Jonathan Fowley in 1995, as well as a later (2010) work Other scientists, tropical forests are responsible for 25–34% of the total photosynthesis occurring on land. How declares Jadwinder Malhi, an ecologist from the Institute for Environmental Changes of Oxford University, this suggests that about 12-16% of oxygen produced on land falls on the rain forests of the Amazon. However, there is also phytoplankton in the oceans. The ocean is approximately half In total, photosynthesis, which means, according to scientists, that in the global sense, the share of the forests of the Amazona falls up to 6–9%.

But that's not all. Trees not only “exhale” oxygen - they also consume it in a process known as cellular respiration when they convert sugar accumulated during the day. Therefore, at night, in the absence of the sun necessary for photosynthesis, plants become pure oxygen absorbers. How They think Researchers from the Malchi group, trees inhale more than half of the oxygen they produced, and the rest is likely to use countless microbes living in the Amazon. “A pure [oxygen] effect of the Amazon or any other biomer is approximately equal to zero,” Malhi says.

As for the atmosphere of the Earth, for the oxygen that we breathe, people should be grateful primarily to phytoplankton, for billions of years steadily allowing this substance to accumulate in the air, Writes Professor of the University of Colorado, atmosphere of the Earth Scott Denning. Thus, despite the fact that the photosynthesis of plants is responsible for oxygen, only a negligible part of this process actually replenishes the reserves of oxygen in the air. According to Denning, even if all organic substances on Earth were burned at the same time, less than 1% of the world oxygen would be spent. And the common figure about the Amazon forests most likely migrated from studies about their role in photosynthesis on land.

Photo on the cover: Wikipedia.