Known as the “Amazon of the seas”, the Coral Triangle is a 5.7 million sq. km expanse across the tropical waters of Indonesia, Malaysia, Papua New Guinea, the Philippines, Solomon Islands, and Timor-Leste — and the richest marine ecosystem on the earth. The Triangle is home to more than three-quarters of the world’s coral species, a third of all reef fish, the vast mangrove forests, and six of the seven marine turtle species. It also sustains the food security and livelihoods of more than 120 million people.
The Coral Triangle is also facing mounting dangers. Growing carbon emissions, destructive fishing, air, water, and soil pollution, and the accelerating effects of climate change are all driving coral bleaching, habitat loss, and species decline, placing both biodiversity and coastal communities at grave risk.
Dangerously exposed
According to the Status of Coral Reefs of the World 2020 report, the planet lost 14% of its corals between 2009 and 2018. Scientists have warned that without drastic action to keep global warming to 1.5º C, 70-90% of live coral cover could be lost by 2050. According to the UN Environment Programme, ocean temperatures may take decades to stabilise even under the most ambitious climate targets, leaving coral ecosystems dangerously exposed in the interim.
In one form of resistance against these threats, the Philippines is preparing to host Southeast Asia’s first coral larvae cryobank to help restore and protect reefs. Set up by the University of the Philippines Marine Science Institute, the facility will freeze and preserve coral larvae — the small, free swimming “seeds” of corals — at very low temperatures. These larvae can later be used to revive damaged reefs or for research, thus protecting genetic diversity that might otherwise be lost.
The project is part of a wider regional initiative that links research institutions in the Philippines, Taiwan, Indonesia, Malaysia, and Thailand to create a network of cryobanks across the Coral Triangle.
Led by Chiahsin Lin of Taiwan’s National Museum of Marine Biology and Aquarium and the National Dong Hwa University, the cryobank is supported by the Coral Research & Development Accelerator Platform through the Marine Environment and Resources Foundation, Inc.
Delicate process
Experts have said the programme is a significant step in building long-term resilience for one of the world’s most threatened marine ecosystems.
“The Philippines is showing other nations how to take a direct, proactive role in fighting the climate crisis and protecting their natural resources. It’s an act of hope and a vital investment in our oceans’ future,” said Preeyanuch Thongpoo, who is working on cryopreservation in Thailand at the Phuket Rajabhat University.
Dr. Lin is guiding the scientists from participating countries to establish the required facilities. At the heart of the effort is the delicate process that preserves coral larvae without damaging their fragile cells.
A study published in Frontiers in 2023 described a technique called vitrification, where the larvae are exposed to special protective solutions before being plunged into liquid nitrogen at –196º C. The rapid freezing that ensues turns the larvae into a glass-like state, preventing the formation of ice crystals that would otherwise destroy them.
To revive the samples, scientists use an equally swift method using lasers, which thaw the larvae in a fraction of a second to avoid re-crystallisation. Once warmed, the larvae are gradually rehydrated in seawater and checked for signs of life, such as swimming and settling, before being transferred to tanks for further growth.
This breakthrough method ensures genetic material from corals can be safely stored for years and later used to help restore damaged reefs.
‘No endangered species’
Cryobanks of coral symbionts — microscopic algae living inside corals — are crucial to reef survival. One is being set up at Phuket Rajabhat University under Dr. Thongpoo’s leadership. Her team is working with cauliflower corals (Pocillopora sp.), chosen for their abundance and ability to recolonise heat-damaged reefs.
“Unfortunately, due to technical challenges with our coral husbandry system, the corals did not survive in captivity, which has prevented us from collecting the larvae required for our experiments,” Dr. Thongpoo said. “We are now working on refining our husbandry protocols and adapting our approach to ensure we can successfully collect and cryopreserve larvae in the near future.”
Cryopreserving many coral species is challenging: their larvae and reproductive cells are large, lipid-rich, sensitive to cold, and often contain algae that block cryoprotectants.
Dr. Lin also stressed that preservation isn’t confined to endangered species. “For me, there’s no endangered species. All coral species are endangered,” he said, warning that most could collapse by 2050. His team began with ‘model’ species such as Pocillopora, which directly releases larvae, and spawning corals like Acropora and Galaxsia.
“You need to set up the model coral species and then use those optimal freezing protocols on the endangered species,” he explained. This approach, he added, differs from projects that prioritise only the most threatened species.
‘Genetic insurance policy’
For now, the scale of reef loss is sobering. Dr. Lin warned that “in the near future, cryobanks may become museums for extinct coral species.”
For Dr. Thongpoo, on the other hand, the effort represents hope: “Cryopreservation is a genetic insurance policy for the future. We are essentially building a living seed bank of coral larvae and Symbiodiniaceae.”
Dr. Lin and Dr. Thongpoo also said local communities that depend on the reefs for their livelihoods are often unaware of their value. In Southeast Asia, tourism, waste discharge, and destructive fishing have worsened reef decline. Without active community participation, they warned, conservation efforts alone won’t save corals.
With regional collaboration between scientists, governments, universities, and local communities, the project aims to strengthen resilience and secure the Coral Triangle’s reefs for generations to come.
Neelanjana Rai is a freelance journalist who writes about indigenous community, environment, science and health.
Published – October 06, 2025 05:30 am IST