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A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. [1] Most coral reefs are built from stony corals, whose polyps cluster in groups. Coral belongs to the class Anthozoa in the animal phylum Cnidaria, which includes sea anemones and ...
A major scientific controversy over the origin of coral reefs took place in the late 19th century, between supporters of Darwin's theory (such as the American geologist James Dwight Dana, who early in his career had seen coral reefs in Hawaii and Fiji during the 1838–42 United States Exploring Expedition), and those who supported a rival ...
The classification of corals has been discussed for millennia, owing to having similarities to both plants and animals. Aristotle's pupil Theophrastus described the red coral, korallion, in his book on stones, implying it was a mineral, but he described it as a deep-sea plant in his Enquiries on Plants, where he also mentions large stony plants that reveal bright flowers when under water in ...
Every year, reefs provide about $2.7 trillion in goods and services, from tourism to coastal protection, according to a 2020 estimate by the Global Coral Reef Monitoring Network.
Coral reef at Nusa Lembongan, Bali, Indonesia Pamalican island with surrounding reef, Sulu Sea, Philippines A reef surrounding an islet Reefs off Vanatinai Island in the Louisiade Archipelago. A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. [1]
For the atoll to persist, the coral reef must be maintained at the sea surface, with coral growth matching any relative change in sea level (sinking of the island or rising oceans). [ 4 ] An alternative model for the origin of atolls is called the antecedent karst model.
Nearby, a group of coral fragments was starting to take root; the researchers had nursed them back to health on land before they replanted them on the reef. Eventually, they plan to place 22,000 ...
Aerial view of Ningaloo Reef in Western Australia, the largest fringing coral reef in the world and a UNESCO World Heritage Site. Fringing reefs are located near shore in the tropics in many areas and are the most common reef type. Coral reefs are found in the tropics in which the water is between 18 and 30 °C (64 and 86 °F). [6]