Coral reefs are one of the oldest and most diverse ecosystems on Earth, with some of them being over 20 million years old. ¹⁾

Coral reefs are formed by colonies of small animals called coral polyps that extract calcium carbonate from seawater to build their skeletons. ²⁾

Coral reefs are often referred to as “the rainforests of the sea” because of their rich diversity of plant and animal life. ³⁾

The Great Barrier Reef, located off the coast of Australia, is the largest coral reef system in the world, stretching over 1,400 miles. ⁴⁾

Coral reefs provide critical habitats and nursery grounds for numerous species of fish, including many commercially important species. ⁵⁾

Coral reefs are also important tourist destinations, generating billions of dollars in revenue each year from activities such as diving and snorkeling. ⁶⁾

Coral reefs act as natural breakwaters, protecting coastlines from the impacts of waves and storms. ⁷⁾

Coral reefs are facing significant threats, including climate change, pollution, overfishing, and disease. ⁸⁾

The warming of seawater and the acidification of the oceans, both of which are consequences of climate change, are among the biggest threats to coral reefs. ⁹⁾

Coral reefs also play a significant role in the carbon cycle, absorbing large amounts of carbon dioxide from the atmosphere. ¹⁰⁾

Coral reefs are home to many species of algae, which provide the coral with energy through photosynthesis. ¹¹⁾

Coral reefs are also important sources of new medicines, with compounds extracted from coral and other reef organisms being used to treat a wide range of illnesses. ¹²⁾

Some species of coral can grow as much as 9 cm per year, making them some of the fastest-growing organisms on Earth. ¹³⁾

The colors of coral reefs are created by the algae that live in symbiosis with the coral, with different species of coral and algae producing different colors. ¹⁴⁾

There are over 500 species of coral found on reefs around the world, with each species having its own unique characteristics and adaptations. ¹⁵⁾