coral

coral, small, sedentary marine animal, related to the sea anemone but characterized by a skeleton of horny or calcareous material. The skeleton itself is also called coral. Although most corals form colonies by budding, there are some solitary corals; in both types the individual animals, called polyps, resemble the sea anemone in form.

Corals grow in warm and temperate climates and in the cold water found at greater depths, but they are most abundant in warm, shallow water; over 200 coral species are found in the Great Barrier Reef of Australia. In many shallow-water species the polyps contain unicellular plants, which may provide the high oxygen concentration required by such corals. Unusually warm water temperatures resulting from global warming, however, can be devastating to corals and coral reefs, either by causing coral species to expel the plants they depend on or by killing the corals themselves.

Sections in this article:

• Introduction
• Classification
• Soft Corals
• Stony Corals

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