🔹 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