Coral Reefs

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

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