How was the great barrier reef formed as a land form?

Answer 1

The reefs require adequate amount of sunlight. They grow only in shallow and clean water. A reef can be made of any of the three substances - sand, rock or coral. The temperature that is conducive for the formation of reefs is between 18 degree Celsius and 30 degree Celsius.

The sea animals called polyps form colonies that make the reefs. A coral polyp resembles a sea anemone. This animal has many tentacles around its mouth. Many polyps join together to form a colony. The Barrier Reef is made of many coral reefs. Each coral polyp is associated with an alga. The photosynthesis by an alga helps the polyp to make a coral skeleton. The skeletons are made of aragonite, a form of calcium carbonate. These coral skeletons form quickly and are the foundation on which coral reefs are built. Two coral skeletons are sealed together by calcium carbonate produced by algae. Thus the reefs including the Great Barrier Reef are formed due to the association between a sea animal and a single-celled plant.