SINGAPORE - Amid warnings of the largest recorded global bleaching event, Singapore’s corals are showing signs of recovery as sea surface temperatures began to fall, with about 20 per cent to 30 per cent of them still showing signs of bleaching.

But the marine heatwave has taken its toll on some corals here, with the corals off Kusu Island showing the most severe bleaching in July.

About 90 per cent of corals then were bleached and half of these affected corals showed signs that they could be dead, the National Parks Board (NParks) and National University of Singapore (NUS) told The Straits Times.

This comes amid the most extensive global coral bleaching event, which saw 77 per cent of the world’s coral reef areas subjected to bleaching-level heat stress, Reuters reported on Oct 18.

In mid-April, the United States National Oceanic and Atmospheric Administration (NOAA) declared the global bleaching event, making it the fourth of its kind.

Global coral bleaching also took place in 1998, 2010 and 2016, and Singapore experienced mass coral bleaching then. Those years and 2024 are El Nino years, a climate phenomenon that causes sea surface temperatures in the eastern Pacific to heat up and elevate global temperatures.

Corals get their vibrant colours from microscopic algae that live in their tissues. When they get stressed from rising sea temperatures, the corals expel the algae and turn ashen white...