Where do we get 70% of oxygen?

Around 70% of the oxygen we breathe comes from the ocean, not from trees or plants on land as many people think. Tiny marine organisms called phytoplankton—which include algae, cyanobacteria, and diatoms produce this oxygen through photosynthesis. During this process, they use sunlight, water, and carbon dioxide to make their food and release oxygen as a byproduct.

Even though these organisms are microscopic, their vast numbers make them the planet’s largest oxygen producers. They float near the ocean’s surface, forming the base of the marine food chain and helping maintain the balance of gases in Earth’s atmosphere. Land-based plants, trees, and forests like the Amazon also contribute significantly, but the oceans are the true lungs of our planet. Without phytoplankton, the oxygen levels on Earth would drastically drop, affecting all living beings that rely on it to survive.

Protecting the oceans, therefore, isn’t just about saving marine life, it’s about safeguarding the air we breathe every day. Pollution, global warming, and ocean acidification can harm these organisms, which could reduce global oxygen production and disturb Earth’s delicate balance.