πΉ What are Coral Reefs?
Coral reefs are underwater structures made by tiny marine animals called corals.
π Corals secrete calcium carbonate (limestone) which forms hard structures over time.
- Main organisms: Coral polyps
π Where are Coral Reefs Found?
- In warm, shallow, clear tropical oceans
- Mostly between 30Β°N and 30Β°S latitudes
πΉ Major Regions
- Indo-Pacific region
- Caribbean Sea
- Red Sea
π Famous example:
- π¦πΊ Great Barrier Reef
πͺΈ Types of Coral Reefs
1. Fringing Reef
- Found close to the coast
- Most common type
π Example: Along island shores
2. Barrier Reef
- Located parallel to the coast but separated by a lagoon
π Example: Great Barrier Reef
3. Atoll
- Ring-shaped reef surrounding a lagoon
- Formed over submerged volcanic islands
π Associated with Charles Darwin
π‘οΈ Conditions for Growth
- Temperature: 20Β°C β 30Β°C
- Clear, shallow water (sunlight needed βοΈ)
- Low pollution
- Normal salinity
π Importance of Coral Reefs
1. Marine Biodiversity π
- Called βRainforests of the Seaβ
- Provide habitat to many species
2. Coastal Protection π‘οΈ
- Protect shores from waves and storms
3. Economy π°
- Tourism & fishing support livelihoods
β οΈ Threats to Coral Reefs
- Rising temperature β Coral Bleaching
- Pollution π
- Overfishing π£
- Ocean acidification
π‘οΈ Coral Bleaching
π When corals lose their color due to stress:
- Caused by warming oceans (e.g., Global Warming)
- Corals expel algae β turn white β may die
π― Important Exam Points
- Coral reefs are made of calcium carbonate
- Found in warm, shallow tropical waters
- Types: Fringing, Barrier, Atoll
- Largest reef β Great Barrier Reef
- Threat β Coral bleaching
