Coral reefs cover less than 0.1% of the ocean floor but protect 150,000km of shoreline in more than 100 countries and territories.

The Economist

Coral reefs cover less than 0.1% of the ocean floor but protect 150,000km of shoreline in more than 100 countries and territories. The colours that lure tourists are produced by single-celled algae that grow symbiotically in corals’ tissue. These use carbon dioxide respired by their host to make oxygen and carbohydrates through photosynthesis