Coral Reefs

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Local Factors Affecting Location of Coral Reefs:

Wave action - coral thrive well in oxygenated water, they prefer strong wave action but not too exposed to frequent storm conditions which can destroy the corals

Sediment - corals require clean, clear water as sediment clogs up their feeding mechanisms and reduces iight available for photosynthesis

Exposure to air - corals die if they are exposed to air for too long so growth of reefs is limited to low tides

Water depth - most reefs grow in depths of 25m or less on the margins or continents or islands

Nutrients - corals grow well in water that is nutrient poor

Global Factors Affecting Location of Coral Reefs:

Light - needed for photosynthesis

Temperature - reefs don't develop where average water temperatures fall below 18 degrees. The best conditions are between 23 and 25 degrees

Salinity - corals are marine creatures that are intolerant of a salt content less than 30,000 - 32,000 ppm. They prefer a high salt content

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Great Barrier Reef;

World's largest coral reef system - 2900 separate coral reefs

Over 2000 km of mangroves with species representing 54% of the worlds mangrove diversity

6000 km squared of seagrass beds

Includes 900 islands ranging from small coral bays to large continental islands

Goods and Services:

$5.7 billion to Australian economy

66,000 jobs

Pharmaceuticals/skin care products

Worth $345 billion to the world economy

50% of the Maldives economy linked to coral reefs

Act as a coastal defence

Threats:

Tourism

Overpopulation

Coral Harvesting

Pollution

Overfishing - dynamite, trawling, poison

Coral bleaching

Chopping down mangroves

Sedimentation

Oil spills

White band syndrome

Ocean acidification