# Where does oxygen come from on earth?

By [Mary](https://paragraph.com/@mary-31) · 2023-02-10

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Most people think that the main source of oxygen is our forests with trees, grass and plants. But as it turned out, all vegetation on land emits only 20% of the earth's oxygen. The remaining 80% of oxygen is given to us by the seas and oceans due to phytoplankton. These are microscopic algae that release a huge amount of oxygen as a result of the photosynthesis reaction.

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*Originally published on [Mary](https://paragraph.com/@mary-31/where-does-oxygen-come-from-on-earth)*