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The Great Barrier Reef near the Australian coast is the world's largest single structure made by living organisms. The reef provides life for thousands of different species. Related to most ecosystems, it is a very important part of the biosphere. However, for the past forty years it has been in danger of disappearing.
Scientists first noticed that something was wrong in the early 1980s: the reef's beautiful rainbow colours seemed to be fading. Because of the smallest rise in water temperature (only by 1–2 degrees Fahrenheit), the microscopic seaweeds that live inside corals started to produce reactive chemicals that are toxic to the reef. This leaves the corals vulnerable to disease and starvation, and eventually kills them. Corals that expel seaweeds from their tissue lose colour and usually become white. This process is called coral bleaching.
Marine biologists have been trying to sound the alarm, but without much success. By 2017, about 30 percent of Earth's tropical reefs had died from heat stress, and the situation keeps getting worse. The collapse of reef ecosystems will change the ocean environment and is likely to have a domino effect on other ecosystems as well.
However, we still have the chance to save the situation. To protect corals, we need to take steps to stop — or at least to slow down — the climate change. While governments are trying to agree on complex global initiatives, we can take small actions on a daily basis, such as raising awareness, saving energy, eating less meat, and reducing waste.