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Formation of Coral Reefs

Reef formation The prime reef builders are the stony or hard corals (subphylum Anthozoa). Reefs are formed by the skeletons of the tiny coral polyps. A coral polyps consist of a fleshy sack with a ring of tentacles which sits in a limestone skeletal case, secreted by the polyp. Reef-building corals have evolved an indispensable symbiotic relationship with a type of brown algae called zoxanthellae (Symbiodinium microadriaticum). Millions of these single-celled algae are living as symbionts within their tissues (hermatypic corals). Zooxanthellae produce sugars and oxygen through photosynthesis thus helping the coral in the process of producing limestone or calcium carbonate. Corals grow up to three times faster with the help of the zooxanthellae. Zooxanthellae give the corals their characteristic greenish color. A change of environmental conditions such as higher temperatures or a change in salinity but also disease can cause the polyps to expel the algae. The coral becomes totally white (= coral bleaching). If the coral regains some algae it might survive, but bleaching can be irreversible and then the coral dies. This website has great terms graphics maps etc

Corals are a group of small, tropical marine animals that attach themselves to the seabed and form extensive reefs, commonly in shallow, warm-water seas. These reefs are made up of the calcium-carbonate (limestone) skeletons of dead coral animals. Coral reefs form the basis of complex marine food webs that are richer in species than any other ecosystem (community of plants and animals). Read more: Coral - humans, body, water, Earth, life, plants, form, animals, waves, surface, Biology of corals, Formation of coral reefs­Co/Coral.html

Coral reefs are formed mainly by the hard skeletons of corals and the limestone deposits of coralline algae and other marine animals. Reefs grow upward as generations of corals produce limestone skeletons, die, and become the base for a new generation. Coral reefs lie in a zone of water 30°N to 30°S of the equator.

Reef-forming coral animals flourish only in water under 100 feet (30 meters) deep and warmer than 72°F (22°C). Coral reefs are classified into three main types. Fringing reefs grow close to the shore of a landmass, extending out like a submerged platform. Barrier reefs also follow a coastline, but are separated from it by wide expanses of water. Atolls are ring-shaped reefs surrounding lagoons. The Great Barrier Reef of northeast Australia is the largest structure on Earth created by a living thing. It is 10 to 90 miles (16 to 145 kilometers) Read more: Coral - humans, body, water, Earth, life, plants, form, animals, waves, surface, Biology of corals, Formation of coral reefs­Co/Coral.html

Appearing as solitary forms in the fossil record more than 400 million years ago, corals  are extremely ancient animals that evolved into modern reef­building forms over the last  25 million years. Coral reefs are unique (e.g., the largest structures on earth of  biological origin) and complex systems. Rivaling old growth forests in longevity of their  ecological communities, well­developed reefs reflect thousands of years of history  (Turgeon and Asch, in press).

Coral reefs form in shallow water that is at a nice warm temperature. Coral forms near land and in the tropics. They are very rich in life. Clown fish and many other organisms can be found here. Coral reefs are very tall and can stretch for miles. The coral is formed by polyps, and when they die they leave behind a stony limestone structure. Only the coral that are hard can form coral. It is very vulnerable

to death. If it is kicked, even slightly, it will most likely die. Coral can also die by turning white. There are three types of coral: fringing coral, barrier coral, and coral atolls. Fringing coral forms along continental shelves and coast lines. Barrier coral runs parallel to the shorelines and are separated by lagoon. Coral atolls grow on top of old sunken volcanoes. Coral reefs are a very important ecosystem. They contain a lot of rich resources such as new medicines. They are very delicate and even a slight temperature change can stress them. Chemicals kill them and can block the needed sunlight out. Coral reefs are usually found in bright colors such as: orange, tan, yellow, purple, and green. Coral reefs will be wiped out very shortly so we really need to protect them.

Stony corals are a remarkable group of animals that inhabit tropical marine waters around the world and form vast colonies known as coral reefs. Coral reefs often resemble rock formations or even plants but such resemblances are only superficial. Coral reefs are in fact made up of many tiny animals known as coral polyps. Each coral polyp is an individual animal and the individual polyps coexist as part of a larger colony of polyps. Coral reefs are extremely diverse and are considered to be one of the most  multifunctional and economically important coastal marine ecosystems. These reefs are  productive shallow water marine ecosystems and are considered to be one of the greatest  natural treasures of the world (Cesar, Herman). They are composed of lime skeletons, 

which are formed through successive growth and deposition of reef­building corals and  coralline algae.  Each reef­building coral contains many coral polyps and symbiotic algae called  zooxanthellae that live within the coral tissues. Each coral polyp is an individual coral,  which withdraws into the coral skeleton during the day. The zooxanthellae  photosynthesize organic compounds from sunlight and these compounds are used for  food for the coral (Davidson, Osha Gray). It is considered a mutualistic symbiotic  relationship because the coral benefits from the algae, but the algae also benefit from the  coral. The coral produce carbon dioxide and nitrogen as a waste product, which serves as  a food source for the zooxanthellae. This mutualistic relationship will not allow the coral  or zooxanthellae to live without each other. Because of this relationship with the algae  the corals have restricted environments. The symbiotic algae require sunlight for  photosynthesis and can be easily destroyed by effects such as sedimentation, thereby  killing the entire coral (Miller, Stephen).  These ecosystems are filled with the highest densities of animals on the globe and surpass  even the tropical rainforests in terms of diversity (Spalding et al). Because of their  immense diversity, they are of great interest to scientists, pharmaceutical companies,  health professionals, and others. ropogenicEffectsonCor.html

Formation of coral reefs  
Formation of coral reefs  

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