31 Facts About Coral reefs


Coral reefs belongs to the class Anthozoa in the animal phylum Cnidaria, which includes sea anemones and jellyfish.

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Coral reefs first appeared 485 million years ago, at the dawn of the Early Ordovician, displacing the microbial and sponge reefs of the Cambrian.

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Coral reefs deliver ecosystem services for tourism, fisheries and shoreline protection.

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Coral reefs are found in the deep sea away from continental shelves, around oceanic islands and atolls.

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Coral reefs theorized that uplift and subsidence of Earth's crust under the oceans formed the atolls.

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Where the bottom is rising, fringing reefs can grow around the coast, but coral raised above sea level dies.

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Two main variables determining the geomorphology, or shape, of coral reefs are the nature of the substrate on which they rest, and the history of the change in sea level relative to that substrate.

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Fringing Coral reefs follow coastlines and can extend for many kilometres.

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Fringing Coral reefs are initially formed on the shore at the low water level and expand seawards as they grow in size.

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Barrier Coral reefs are separated from a mainland or island shore by a deep channel or lagoon.

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Unlike fringing and barrier Coral reefs which extend only seaward, platform Coral reefs grow in all directions.

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Atolls or atoll Coral reefs are a more or less circular or continuous barrier reef that extends all the way around a lagoon without a central island.

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The Coral reefs surrounding islands form when islands subside into the ocean, and atolls form when an island subsides below the surface of the sea.

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Coral reefs are rare along the west coasts of the Americas and Africa, due primarily to upwelling and strong cold coastal currents that reduce water temperatures in these areas.

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Coral reefs heads consist of accumulations of individual animals called polyps, arranged in diverse shapes.

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Coral reefs polyps do not photosynthesize, but have a symbiotic relationship with microscopic algae of the genus Symbiodinium, commonly referred to as zooxanthellae.

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Coral reefs that loses a large fraction of its zooxanthellae becomes white and is said to be bleached, a condition which, unless corrected, can kill the coral.

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At long distances sounds from existing Coral reefs are likely important, while at short distances chemical compounds become important.

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Oyster Coral reefs are dense aggregations of oysters living in colonial communities.

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Coral reefs often depend on surrounding habitats, such as seagrass meadows and mangrove forests, for nutrients.

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Healthy Coral reefs can produce up to 35 tons of fish per square kilometer each year, but damaged Coral reefs produce much less.

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Coral reefs deliver ecosystem services to tourism, fisheries and coastline protection.

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Bermuda's coral reefs provide economic benefits to the Island worth on average $722 million per year, based on six key ecosystem services, according to Sarkis et al.

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Coral reefs protect shorelines by absorbing wave energy, and many small islands would not exist without reefs.

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Coastlines protected by coral reefs are more stable in terms of erosion than those without.

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Since their emergence 485 million years ago, coral reefs have faced many threats, including disease, predation, invasive species, bioerosion by grazing fish, algal blooms, and geologic hazards.

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Direct human pressure on coral reefs should be reduced and the inflow of sewage should be minimised.

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Coral reefs seeds are grown in nurseries, then replanted on the reef.

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Coral reefs is farmed by coral farmers whose interests range from reef conservation to increased income.

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Coral reefs gardens take advantage of a coral's natural ability to fragment and continuing to grow if the fragments are able to anchor themselves onto new substrates.

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Efforts to expand the size and number of coral reefs generally involve supplying substrate to allow more corals to find a home.

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