Thermal Stress : A Prime Cause of Coral Bleaching

Increasing carbon dioxide (CO₂) concentrations in the atmosphere are driving higher levels of acidification in the world’s oceans. As CO₂ is absorbed by seawater, it reacts with water molecules to form carbonic acid, lowering the pH and making the oceans more acidic. This acidification has a direct impact on coral reefs, one of the most diverse ecosystems on Earth. When coral polyps expel the symbiotic algae called zooxanthellae due to stress from acidification, the corals lose their color, a phenomenon known as coral bleaching. The loss of these algae deprives the coral of essential nutrients, leaving them vulnerable to disease, reduced growth, and even death. As acidification intensifies, the ability of corals to rebuild their calcium carbonate skeletons is hindered, further exacerbating the damage. This degradation not only threatens coral biodiversity but also the livelihoods of millions of people who depend on healthy reefs for food and tourism.