CORAL REEF (Syllabus: GS Paper 3 – Env and Eco)

Context: Scientists have mapped the largest coral reef deep in the ocean, stretching hundreds of miles off the U.S. Atlantic coast.

Coral Reef

• About: Coral reefs are some of the most diverse ecosystems in the world.
• Structure: Coral reefs are massive structures made of limestone deposited by coral polyps.
• Referred to as: Rainforests of the sea. Coral reefs support approximately 25 percent of all known marine species
• Condition of its growth:

oWarm water temperature: Corals generally live in water temperatures of 20–32° C.

oSunlight: Corals need to grow in shallow water where sunlight can reach them. Zooxanthellae (algae) needs sunlight for photosynthesis.

oSalinity: Corals need saltwater to survive.

• Sunlight: Abundant sunlight available. 
• Temperature: The temperature of the water should be around 20°C. 
• Types of coral reef: Fringing Reefs, Barrier Reefs, Atolls.
• Coral reef in India: Andaman and Nicobar Islands, Gulf of Mannar, Gulf of Kutch, Palk Strait and the Lakshadweep islands.

Coral Bleaching: When corals are stressed by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae microscopic algae called zooxanthellae living in their tissues, causing them to turn completely white.