🔹 What are Coral Reefs?

Coral reefs are underwater structures made by tiny marine animals called corals.

👉 Corals secrete calcium carbonate (limestone) which forms hard structures over time.

• Main organisms: Coral polyps

🌍 Where are Coral Reefs Found?

• In warm, shallow, clear tropical oceans
• Mostly between 30°N and 30°S latitudes

🔹 Major Regions

• Indo-Pacific region
• Caribbean Sea
• Red Sea

👉 Famous example:

• 🇦🇺 Great Barrier Reef

🪸 Types of Coral Reefs

1. Fringing Reef

• Found close to the coast
• Most common type

👉 Example: Along island shores

2. Barrier Reef

• Located parallel to the coast but separated by a lagoon

👉 Example: Great Barrier Reef

3. Atoll

• Ring-shaped reef surrounding a lagoon
• Formed over submerged volcanic islands

👉 Associated with Charles Darwin

🌡️ Conditions for Growth

• Temperature: 20°C – 30°C
• Clear, shallow water (sunlight needed ☀️)
• Low pollution
• Normal salinity

🌊 Importance of Coral Reefs

1. Marine Biodiversity 🐠

• Called “Rainforests of the Sea”
• Provide habitat to many species

2. Coastal Protection 🛡️

• Protect shores from waves and storms

3. Economy 💰

• Tourism & fishing support livelihoods

⚠️ Threats to Coral Reefs

• Rising temperature → Coral Bleaching
• Pollution 🏭
• Overfishing 🎣
• Ocean acidification

🌡️ Coral Bleaching

👉 When corals lose their color due to stress:

• Caused by warming oceans (e.g., Global Warming)
• Corals expel algae → turn white → may die

🎯 Important Exam Points

• Coral reefs are made of calcium carbonate
• Found in warm, shallow tropical waters
• Types: Fringing, Barrier, Atoll
• Largest reef → Great Barrier Reef
• Threat → Coral bleaching