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🇸🇬 Singapore /Environment & Climate

‘Slumping’ South Korean corals alarm divers and climate researchers

From The Straits Times · () English

Translated from English and summarized by DistantNews. Read the original for the full story.

At a glance

In-depth Named sources Ongoing story
  • Soft corals around South Korea’s Jeju Island are again sagging and dying after two years of rising temperatures and harsher weather.
  • Citizen scientists estimate that about half of one coral cluster near Beomseom has struggled in recent months, while researchers warn prolonged heat and El Niño-related weather could worsen the damage.
  • South Korean heritage and oceans authorities plan continued monitoring and detailed research into the causes and scale of the decline.

Ko Myeong-hyo remembers Jeju’s soft corals as a vivid underwater garden. Six years ago, she began diving off the island to harvest seafood for sale. Now she watches many of the corals sag, turn white and die.

“Watching the coral garden collapse and turn white, it was so disorienting,” Ko said. “I was afraid the whole sea might be collapsing.”

Watching the coral garden collapse and turn white, it was so disorienting.

· Ko Myeong-hyoThe diver described seeing Jeju’s previously vibrant soft corals deteriorate.

The phenomenon has returned in 2026, according to the Paran Ocean Citizen Science Centre, a group of divers monitoring Jeju’s UNESCO-listed soft corals, mainly around uninhabited islets south of the island. The group says roughly half of one cluster off Beomseom has struggled in recent months.

Soft corals differ from hard corals because they lack rigid calcium carbonate skeletons. They depend on internal fluid pressure to remain upright. Environmental changes can disrupt that pressure, causing the corals to sag or collapse.

“If another large-scale ‘slumping’ happens, corals partially recover and then a lot break off and deteriorate again, and that keeps repeating, their capacity to recover just keeps declining,” researcher Kim Taihun said. Kim and Korea Institute of Ocean Science and Technology colleague Anna Beate Jöst documented Jeju’s 2024 slumping event in a May article published in Scientific Reports.

I was afraid the whole sea might be collapsing.

· Ko Myeong-hyoShe expressed her alarm at the scale of the coral decline.

Kim said the 2026 event resembled the earlier episode but could worsen if high water temperatures persist through September. He also said El Niño could bring typhoons and heavy rain. Researchers identify warmer conditions, severe weather and changes in salinity from water flowing from China’s Yangtze River as possible triggers.

The Korea Heritage Service, which manages the soft coral colonies designated as a national monument, said it has monitored the situation and will continue long-term research. The Oceans Ministry said it plans a detailed investigation to assess the damage. Kim called for consistent, quantitative monitoring, citing limited research support.

If another large-scale ‘slumping’ happens, corals partially recover and then a lot break off and deteriorate again, and that keeps repeating, their capacity to recover just keeps declining.

· Kim TaihunThe researcher warned that repeated slumping events could weaken the corals’ ability to recover.
About this summary

Originally published by The Straits Times in English. Translated, summarized, and contextualized automatically by DistantNews, with a note on how the source frames the story. Not individually reviewed before publishing. How this works.

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