What color is coral? What colors make coral?

Interesting facts - Corals are marine invertebrates in the class Anthozoa of phylum Cnidaria. They typically live in compact colonies of many identical individual polyps. The group includes the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton. So what color is coral, what colors make coral, what about coral reef? Just keep reading to get the answers and learn more about coral.

What color is coral?

Coral is a colorless marine animal that lives on the ocean floor and can be red, orange and other colors. Any color that appears to be present on coral is a buildup of algae that live on the coral. Like other animals of the sea, coral can change color with emotion.

An individual coral is known as a polyp. Polyps attach themselves to rock along the ocean floor and multiply to form a colony. Each polyp has a hard, protective skeleton at the base that creates a reef when colonies are formed.

Coral are very sensitive to environmental changes such as a change in temperature or pollution. A completely white coral, also referred to as "bleached out," indicates that the animal is stressed. Stressed coral will not allow algae to remain on its surface, placing itself and the rest of the reef it may be attached to in danger.

How do coral reefs form?

Coral reefs start to form when coral larvae attach to rocks or hard surfaces that are submerged under water. Coral polyps secrete calcium carbonate, closing off each layer as they grow bigger. Each polyp bonds itself to other polyps, eventually forming reef structures.

Coral reefs in nature form within 150 feet of the surface of the water since they require sunlight to survive. Reefs grow slowly, varying from 1/2 inch to 3 inches per year depending on the species. Corals and some types of algae have symbiotic relationships. The corals provide a home and carbon dioxide for the algae, and the algae provide food and oxygen to the corals. Coral reefs recycle carbon dioxide and absorb impacts from waves and storms. Corals are animals, with the living corals staying on the outer part of the reef and in deeper waters.

The first coral reefs formed about 500 million years ago. The Great Barrier Reef is 500,000 years old, with the existing reef structure less than eight thousand years old. Barrier reefs, atolls and fringing reefs are the three types of reef structures. Fringing reefs are found closer to land. Atolls are found around lagoons, and barrier reefs are found farther off-shore and most commonly in the Indo-Pacific and Caribbean.

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