Why are coral reefs in warm waters?
Show answer & explanation
Answer: Coral needs warmth to grow
Fish prefer warm temperatures — Wrong. Fish distribution doesn't determine coral location. Coral grows in warm water because the symbiotic algae (zooxanthellae) living in coral tissue require warmth for photosynthesis.
Coral needs warmth to grow ✓ — Correct! Coral polyps have symbiotic algae (zooxanthellae) living in their tissue. These algae photosynthesize, providing up to 90% of coral's energy. They need warm water (20-30°C) and sunlight. Cold water slows algae metabolism. That's why reefs are in tropical shallow waters—best conditions for zooxanthellae!
Less pollution in tropics — Wrong. Pollution doesn't explain reef location. Coral grows in warm tropical waters because symbiotic algae need warmth and sunlight for photosynthesis.