Of them, corals are particularly vulnerable: when the water around them becomes too warm, they are susceptible to bleaching. There is more to bleaching, however: most corals are home to a type of algae called zooxanthellae, which give the corals their colours as well as have a symbiotic relationship with them. Also Read | The phenomenon of coral bleachingWhen the ocean environment changes – for example, if its temperature rises beyond a point, it becomes too acidic, or it becomes too bright – the zooxanthellae living within the coral leave. As they do, the coral fades until it appears to have been bleached; if the corals continue to be stressed, they won’t welcome the algae back and eventually die. Some colonies have been known to survive a bleaching event, like, famously, one near Japan’s Iriomote Island: it was bleached in 2016 but showed signs of recovery in 2020.

Source: The Hindu July 17, 2023 18:06 UTC