Massive coral bleaching is under way in many part of the world thanks to various factors. Here we examine these factors and explain the consequences of coral bleaching

Coral Bleaching, which refers to the coral polyps losing their color and becoming white, takes place under conditions in which zooxanthellae, the symbiotic algae that imparts color to the corals, cannot survive. When corals are stressed by changes in conditions such as temperature, light, or nutrients, they expel zooxanthellae living in their tissues, causing them to turn completely white. Such conditions often find their roots in the process of global warming and manifests in the following forms:

1. Increase (most commonly) or sometimes decrease in sea temperatures creates condition where zooxanthellae, the algae which imparts color to corals cannot survive.
2. Excessive fishing and persistent global warming causes depletion of microorganisms in sea water. This makes the survival of corals tough as there is little left for them to feed on
3. Change in water composition(salinity, acidification, bacterial levels etc.) due to increased industrialization also creates condition that are difficult for the algae to survive

Since coral bleaching is nothing but a reflection of global warming, it has following consequences:

1. Extensive bleaching would indicate an eventual extinction of coral polyps which forms the basis of food chain, thereby disturbing the entire food chain.
2. Consistently rising sea levels, which is also indicated by coral bleaching, will subsume the coastal regions and the resources therein.
3. Eventual fading away of coral reefs, which are home to more than 25% of the ocean life
4. Change in the ocean salinity, which will trigger a chain of events impacting human life, including ocean currents and atmospheric pressure too.