Coral reefs make up some of most beautiful and breathtaking places under the sea. More than being just lovely to look at, coral reefs are an extremely valuable part of nature. This is because they sustain a diverse range of marine life. They also shield coastlines from violent waves and storms, sink carbon and nitrogen, and aid in the recycling of nutrients.\r\n\r\nCoral reefs are often called \u201cthe\u00a0rain forests of the seas." This is because 25 percent of all\u00a0marine\u00a0species live in and around coral reefs, making them one of the most\u00a0diverse habitats in the world. Unfortunately, the United Nations Environment Programme (UNEP) states all of the world\u2019s coral reefs could bleach, unless greenhouse-gas emissions disappear.\r\n\r\nWhat is coral bleaching and how is it stopped? Coral bleaching is the result of a coral's stress response. The coral reef loses its symbiotic algae and pigments during bleaching, it turns white and dies. Heat stress caused by high sea temperatures and increased UV radiation is a major cause of coral bleaching on the Great Barrier Reef during the summer.\r\n\r\nAs we all know, greenhouse gases make the Earth\u2019s temperature higher than usual. We also know they've hit the Earth for a long time now. And, if they have their way, and coral reefs become totally extinct, many sea creatures would be without a home. Coral reef loss can be particularly devastating for areas of the world that depend on them for their primary food source. Even if it may sometimes not seem so, we humans depend heavily on coral reefs for food and other crucial sources.\r\n\r\nAll in all, coral reefs are more important than they look, and are very vulnerable. They're something we should not take for granted. Learn more about them, and how we should preserve them, in our 50 coral reef facts.