Most of the oxygen on Earth comes from photosynthesis carried out by marine organisms, especially phytoplankton, algae, and cyanobacteria in the oceans.
Explanation:
- While forests and trees contribute to oxygen production, the majority is generated in oceans.
- Tiny microscopic organisms called phytoplankton perform photosynthesis using sunlight, carbon dioxide, and water to produce oxygen.
Key Contributors:
- Phytoplankton (major source)
- Algae
- Cyanobacteria (blue-green algae)
Percentage Contribution:
- Oceans contribute approximately 50% to 70% of the Earth's oxygen supply.
- Forests and terrestrial plants contribute the remaining portion.
Why Oceans Play a Major Role:
- Cover about 71% of Earth’s surface
- Contain vast populations of photosynthetic microorganisms
- Continuous photosynthesis due to sunlight penetration in upper layers
Conclusion:
Although trees are important, most of Earth’s oxygen is produced by ocean-based organisms, making marine ecosystems critical for sustaining life.