Coral Reefs Formation and Threats

Corals

• Corals are tiny animals called polyps that live in tropical regions close to the sea floor in warm, shallow waters.
• Corals secrete calcium carbonate, which consolidates into rocks, eventually forming ridge-like structures of coral reefs on the sea floor over time.

Formation of Coral Reefs

• A polyp attaches itself to the sea floor and divides into multiple clones, starting the formation of a reef.
• The hard, limestone skeletons (calicles) at the base of the polyps connect to one another, creating a colony that acts as a single organism.
• The colonies grow over several years and join with other colonies to become reefs.

Threats to Coral Reefs

• Climate change, global warming, human exploitation, and natural predators are causing a rapid decline of coral reefs.
• Coral bleaching occurs when there is an increase in the temperature of ocean water.
• Oil spills and nitrogen run-off from farms make corals vulnerable to bleaching.

The Great Barrier Reef

• The Great Barrier Reef is the world's largest coral reef, located off the northeast coast of Australia.
• It has over 400 types of corals, 1500 species of fish, and 4000 varieties of snails, molluscs, and octopuses.
• The reef is home to rare species of sea cows and large green turtles.
• The reef is a long, narrow, mostly submerged coral formation, extending about 2000 km, lying parallel to the shoreline.