Question

Which of the following is the most significant factor in coral bleaching ?
1. Mining of coral rocks
2. Outbreak of coral diseases
3. Siltation of seawater
4. Global warming

Answer 1

Correct Answer - Option 4 : Global warming

The correct answer is Global warming.

• The zooxanthellae and coral share a symbiotic relationship and 90% of the nutrients that are produced by the algae are transferred to the coral hosts.
• But this symbiotic relationship gets affected under severe environmental stress which causes the loss of symbiotic algae.
• As the result, the White calcium-carbonate exoskeleton is visible through its transparent tissue leading to a condition called "Coral Bleaching".
• The corals become vulnerable in the absence of the zooxanthellae and corals begin to die if the temperature of the sea remains high for weeks.
• Marine pollution, solar radiation, changing salinity, and bacteria are the cause of coral bleaching.
• The leading cause of coral bleaching is Global warming.
• According to the National Oceanic and Atmospheric Association, between 2014 and 2017 around 75% of the world’s tropical coral reefs experienced heat-stress severe enough to trigger bleaching.

• Coral Reefs: -
  • Coral reefs are underwater ecosystems characterized by reef-building corals.
  • Reefs are formed of colonies of coral polyps held together by calcium carbonate.
  • They are referred to as rainforests of the sea.

• Near the earth’s surface, Global warming is the phenomenon of a gradual increase in temperature.
• Volcanoes, Water vapor, Forest Blazes, Melting Permafrost are the natural causes of Global warming.
• Deforestation, Chlorofluorocarbon, Use of Vehicles, Industrial Development, Overpopulation, etc are the man-made causes of Global warming.