Corals are built by tiny polyps, which usually live in colonies. They like warm, clear waters, which is why they can only be found in certain regions of our oceans where conditions are optimal.
Polyps, belonging to the numerous species of stone corals, are protected by a hard calcium carbonate skeleton, which they secret layer by layer. This is how coral reefs develop in centuries.
With poisonous stinging capsules (or nematocysts) on their tentacles, they immobilize floating microorganisms on contact and move them to their mouth opening. In addition, they have another way of obtaining food: they live in a fascinating symbiosis with microscopic algae, the so called zooxanthellae. Algae use the light and provide the corals with oxygen and important nutrients. In addition they remove carbondioxid out of the water and thus triggering a chemical reaction which enables an efficient calcium carbonate production.
Habitat for numerous organisms
Coral reefs are habitat for many different species, including members of the fish, mollusks and crustaceans. There are about 1,000,000 different species in this ecosystem, 65.000 of which are known. Coral reefs are nursery grounds for many fishes, even pelagic fish use them for spawning and foraging. This richness in fish is on the other hand an important food resource for humans.
IMPORTANCE OF REEFS |
