Coral reefs are essential for a healthy ocean—the same ocean that creates more than 50 percent of the oxygen we breathe.

But rising ocean temperatures and ocean acidification caused by climate change are destroying the reef. More than half the world’s corals have already been lost or severely damaged, and if we do nothing, by 2050 coral reefs could be the first entire ecosystem to collapse.

The importance and wonder of coral reefs revealed in three facts

1. Corals are animals

Corals are a point of symbiosis between an animal—the polyp—and an algae known as the zooxanthellae, and we call them “colonies.” Coral polyps are tiny organisms related to sea anemones and jellyfish. They create their own skeleton, which forms the structure of coral reefs. The only animals to have built a structure visible from space, corals give protection to their algae, and in exchange this algae gives them energy via photosynthesis.

2. Coral reefs cover less than 1 percent of the ocean floor, but 25 percent of marine species call them home

Coral reefs cover only 0.0025 percent of Earth’s surface but are among the most biologically diverse and valuable ecosystems on our blue planet. Around 25 percent of all marine life, including over 4,000 species of fish, is dependent on coral reefs at some point during their life cycle. Marine species take shelter, eat, and reproduce in the many alcoves formed by corals.

3. Half a billion people worldwide directly rely on the reef 

Coral reefs absorb 97 percent of energy from waves and therefore protect thousands of islands and millions of people around the world. And because reefs create habitats for myriad marine species, they are crucial to local fisheries and provide food for people living near reef ecosystems, especially on small islands. Reefs also attract vital tourism and create incomes on a local and regional scale.

Learn more in our series on Timor-Leste’s vision for a blue economy, The Last Coral Kingdom