- Scientists in Phuket are freezing coral larvae and their symbiotic algae, aiming to create a “living seed bank” to preserve Thailand’s reef genetic diversity amid accelerating climate stress.
- Thailand’s reefs, home to more than 300 coral species, have experienced repeated mass bleaching events since 2022, with damage compounded by tourism pressure, wastewater runoff, sedimentation and overfishing.
- Researchers describe coral cryobanks as a form of “genetic insurance” and ex-situ conservation, but stress they can’t replace in-water protection and must be integrated into broader restoration and marine management strategies.
- Conservation experts say improving water quality, regulating tourism impacts and strengthening community-led marine protection are essential if preserved coral material is to be successfully restored to the wild.
In a quiet laboratory at Phuket Rajabhat University in southern Thailand, Preeyanuch Thongpoo is attempting to freeze time. As a molecular biologist, her work focuses on the cryopreservation of live larvae and algae to facilitate future restoration.
Inside, suspended in liquid nitrogen at -196° Celsius (-321° Fahrenheit), are vials containing microscopic algae no bigger than specks of dust. Her team is deep-freezing the vital symbiotic algae of the cauliflower coral (genus Pocillopora), from the family Symbiodiniaceae. These live inside coral tissues and provide most of the energy corals need to survive. The larvae of the cauliflower coral itself, a rugged pioneer known for recolonizing heat-damaged reefs, have been preserved in separate vials.
Working as part of the Coral Research & Development Accelerator Platform (CORDAP) initiative, Preeyanuch is building more than a repository; she is creating a “living seed bank” aimed at supporting future reef restoration.
This effort comes at a precarious moment for Thailand’s marine heritage. Coral reefs in Thailand are under pressure from both global climate change and local stressors, including tourism and coastal development. Recent coast-to-coast surveys show that Thailand’s coral reefs, home to more than 300 species of reef-building corals, are losing structural complexity and shifting in species composition after repeated mass bleaching events driven by extreme marine heat waves between 2022 and early 2024, with heat stress in 2024-2025 likely compounding the declines.
Tourism, a pillar of Thailand’s coastal economy, has exacerbated pressures on already stressed reefs. Intensive diving and snorkeling activity have been linked to higher rates of coral breakage, tissue abrasion and disease. Boat anchoring and propeller wash also damage fragile reef structures.
Rapid coastal development has added further strain. Expanding resort infrastructure, shoreline modification and wastewater discharge contribute to sedimentation and nutrient loading in nearshore waters. Elevated nutrients can fuel algal overgrowth, increase microbial activity and reduce coral resilience to heat stress.
While Thailand has long relied on conventional restoration methods, such as physically replanting coral fragments, the accelerating pace of climate-induced bleaching is outstripping these interventions.
Consequently, researchers at Phuket Rajabhat University’s coral cryobank facility, established in June 2025, are working to preserve biomaterial in case reefs can’t survive in the wild.
Chiahsin Lin, a veteran researcher training scientists across the region, describes these banks as “ex-situ conservation,” designed to provide the tools to “point them back” once environmental conditions stabilize. Lin says that because of current climate projections, “all coral species are endangered,” necessitating the archiving of broad genetic diversity to support future recovery.
“To ensure we have a complete genetic library that can be used for future restoration efforts, we must consider all these groups of corals,” Preeyanuch says.
Keystone reef builders are critical as the “architects of the reef structure,” providing habitat and nurseries for marine organisms. Slow-growing massive corals represent long-term resilience and are often more tolerant of disturbances such as bleaching and storms, while fast-growing branching corals are the first to recolonize damaged reefs but are highly sensitive to heat stress.
The goal, Preeyanuch says, is to create reefs that are both biodiverse and better equipped to survive in a warming ocean.
Despite its potential, cryopreservation is no panacea, Lin says. Preserving each coral species comes with unique technical challenges. Progress is slow, while climate-driven reef decay accelerates rapidly. Regional cooperation, sustained government support, and integration with other forms of conservation are essential for success, he says.
A genetic insurance policy
Petch Manopawitr, adviser to the NGO WildAid and a Thai conservation scientist, describes coral cryobanking as a useful but inherently limited intervention. “It provides a long-term genetic insurance policy,” he says, noting that enhancing the genetic diversity of restoration programs is “very, very important,” particularly as many existing restoration efforts rely heavily on coral fragmentation and cloning.
However, Petch says, cryobanks must be part of a solution that includes “real-world conservation,” and ultimately won’t work “unless we have fixed all [the] environmental issue[s] that degraded the reef in the first place.”
“First thing first, we have to address climate change,” he says. “But then locally, we have to improve water quality, we have to address unsustainable tourism practices … anchor damage, physical damage, sedimentation, fishing impact.
“So I think cryobank[ing] is a good, definitely a good project, but it ha[s] to be plugged in, in the whole picture,” Petch says.
That “whole picture,” he says, extends beyond laboratories and government agencies. “More and more local communities, especially coastal communities, small-scale fishermen are very keen to become guardians of the marine environment,” he says. “The idea of locally marine managed areas is very popular, too. The government is also promoting it.”
In several Thai provinces, including Chumphon and Ranong, community groups are already involved in reef conservation and monitoring. These locally led efforts, Petch says, align with global conservation targets while offering a bottom-up approach to marine protection. “It’s something that allows people, local people, to become part of a solution,” he says.
Despite mounting climate risks, including projections that a majority of the world’s coral reefs could decline sharply by 2050, Petch argues against resignation. “We shouldn’t give up in terms of real-world conservation,” he says. Cryobanking is useful “as an insurance,” he adds, but emphasizes that reefs provide ecosystem services that no laboratory archive can replace. “It’s not just the species that we’re losing. We are talking about ecosystem services that coral reefs provide.”
A storage unit for extinction?
Although the Phuket facility faced technical challenges in its first year, including difficulties maintaining broodstock corals in captivity long enough to collect viable larvae, Preeyanuch says the team is refining its husbandry systems, adapting protocols and preparing to receive the second tranche of a three-year research grant from CORDAP.
While acknowledging that reefs can’t realistically be rebuilt from frozen larvae alone at today’s scale of loss, she says the effort is more than symbolic. It is, she says, “the genetic heart of the restoration effort,” preserving diversity and adaptability that future reefs will need.
By capturing larvae during brief spawning windows and storing them for decades, she says, the cryobank “buys us crucial time,” even as she warns that without healthy oceans, it risks becoming “a storage unit for extinction.”
Correction: This article was amended Feb. 22 to clarify that the Phuket Rajabhat University project has already secured funding for its first three years of operation.
Coast-to-coast coral assessment reveals Thailand’s reefs losing complexity
Citations:
Monchanin, C., Desmolles, M., Chankong, A., Nilkerd, N., Sangsawang, L., & Mehrotra, R. (2025). Establishing a baseline for coral reef community structure across Thailand with a review of earlier assessments. Regional Studies in Marine Science, 91, 104577. doi: 10.1016/j.rsma.2025.104577
Lin, B. (2021). Close encounters of the worst kind: Reforms needed to curb coral reef damage by recreational divers. Coral Reefs, 40(5), 1429-1435. doi:10.1007/s00338-021-02153-3
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