Which of the following are the necessary conditions for the growth of coral reefs?
- 1. Photic conditions
- 2. Clean and sediment free water
- 3. Sea salinity of 6%
- 4. Tropical sea water with temperature of 20°C to 21°C
Select the correct answer using the code given below :
1, 2 and 4 only
2 and 4 only
1 and 3 only
1, 2, 3 and 4
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC CAPF – 2017
1. **Photic conditions:** Corals have a symbiotic relationship with photosynthetic algae called zooxanthellae living in their tissues. These algae require sunlight for photosynthesis, which provides energy to the coral. Therefore, coral reefs are typically found in shallow, clear waters within the photic zone.
2. **Clean and sediment free water:** Sediments suspended in water can block sunlight needed by zooxanthellae and can also smother coral polyps. Pollution can also harm corals. Clean water is essential.
3. **Sea salinity of 6%:** This is incorrect. Coral reefs typically require stable salinity levels found in normal seawater, which is usually around 30-40 parts per thousand (ppt), or 3-4%. A salinity of 6% (60 ppt) is significantly higher than optimal and is not conducive to coral growth.
4. **Tropical sea water with temperature of 20°C to 21°C:** Corals thrive in warm tropical and subtropical waters. The ideal temperature range for most reef-building corals is generally between 20°C and 28°C (68°F to 82°F). The range 20-21°C falls within this suitable range.