Q. Which of the following reasons caused catastrophic coral bleaching and mass coral deaths in the Andaman and Nicobar Islands?
(a) Increased industrial activities in the coastal regions
(b) Increase of 2° C temperature in the Indian Ocean
(c) Heavy marine pollution
(d) Decrease of temperature by 4° C in the Indian Ocean
Answer: b
Coral bleaching occurs when corals expel the symbiotic algae (zooxanthellae) living in their tissues due to stress, primarily caused by elevated sea surface temperatures. These algae provide corals with food through photosynthesis and give them their vibrant colors. Without the algae, corals turn white (bleached) and are at risk of dying if stressful conditions persist.
In the case of the Andaman and Nicobar Islands, the primary reason for catastrophic coral bleaching and mass coral deaths was the increase in sea surface temperature by approximately 2°C in the Indian Ocean. This temperature rise is linked to global warming and climate change, which have caused more frequent and intense marine heatwaves.