Singapore’s coral reefs show resilience as sea temperatures drop following widespread bleaching.
SINGAPORE – Despite being affected by the largest recorded global coral bleaching event, Singapore’s coral reefs are showing encouraging signs of recovery. As sea surface temperatures have begun to fall, about 20 to 30 percent of the coral colonies still exhibit bleaching signs, down from 30 to 55 percent observed earlier in the year, according to the National Parks Board (NParks) and the National University of Singapore (NUS).
The global coral bleaching event, declared in mid-April by the US National Oceanic and Atmospheric Administration (NOAA), has affected coral reefs worldwide, with 77 percent of coral areas experiencing heat stress, as reported by Reuters. This phenomenon has been linked to the ongoing El Niño, which raises sea surface temperatures and increases the likelihood of coral bleaching events. Notably, Singapore has also seen similar bleaching events in previous El Niño years, such as in 1998, 2010, and 2016.
Coral bleaching occurs when rising sea temperatures cause corals to expel the algae living within their tissues, which give them their vibrant color. Without these algae, the corals turn ashen and white, losing their vitality. In May, mild bleaching was first reported in Singapore, with corals in Pulau Satumu and Pulau Hantu showing early signs of stress. By mid-July, the bleaching worsened, affecting more than half of the corals at sites like Pulau Hantu, Pulau Satumu, Kusu Island, and Sisters’ Islands.
However, as temperatures began to drop in late July, early signs of recovery appeared. By September, corals started to regain their color, although some still showed partial bleaching. Marine conservationists like Sue Ye, founder of Marine Stewards, noted that 30 percent of hard corals were still exhibiting stress during dives in late September.
The recovery trajectory for Singapore’s corals looks promising, with experts hopeful that by early 2025, the remaining corals will fully recover, assuming no further environmental stressors, such as oil spills, affect the reefs. In June, Singapore faced a significant oil spill, but researchers from the St John’s Island National Marine Laboratory (SJINML) indicated that the spill did not appear to worsen coral bleaching levels.
NParks and NUS are actively monitoring coral health through a tagging initiative involving 100 coral colonies, as part of the Marine Climate Change Science Programme. The research aims to track coral resilience and survival rates under current environmental conditions. Scientists believe that with the right temperature conditions, corals can recover, as their ideal temperature range is between 23°C and 29°C.
As Singapore’s coral reefs begin to heal, ongoing efforts to monitor and understand the impacts of climate change on marine ecosystems remain crucial. NParks is collaborating with local scientists and divers to develop a tool for assessing coral bleaching, which will aid in the timely response and conservation efforts in the future.
