The Great Barrier Reef’s Frozen Noah’s Ark
Deep within the temperature-controlled chambers of Sydney’s Taronga Zoo lie rows of tanks filled with liquid nitrogen, cradling parts of the Great Barrier Reef’s magnificent corals frozen in time. This frosty Noah’s Ark, known as the world’s largest store of cryogenically frozen coral, serves as a vital safeguard for an ecosystem on the brink of extinction due to the looming threat of climate change.
Managed by Justine O’Brien, the conservation science manager at Taronga Conservation Society Australia, this groundbreaking initiative aims to preserve trillions of cells from key coral species found on the Great Barrier Reef. These cells, collected annually during mass spawning events, offer a beacon of hope for the regeneration of damaged and dwindling coral populations.
“By pressing a pause button on their biological clocks, we are striving to retain the reef’s beautiful diversity,” O’Brien expressed with optimism.

Preserving Coral Diversity for Future Generations
Since its inception in 2011, Taronga’s CryoDiversity Bank has been actively involved in collecting sperm from coral species during spawning seasons. By mixing the sperm with cryoprotectants to facilitate the freezing process, scientists ensure that the samples remain viable for an indefinite period.
While current techniques do not allow for the cryopreservation of coral eggs, other types of cells are also harvested and stored for future research purposes. Maintained at a temperature of -196 degrees Celsius, the frozen coral samples are shielded from any fluctuations that could compromise their integrity.
“Whether thawed out in a few years or centuries, these samples will retain their fertilizing potential, offering a lifeline for coral populations facing extinction,” O’Brien explained.

Race Against Time: Saving Coral Reefs from Extinction
With coral disease and death on the rise, the CryoDiversity Bank has prioritized the preservation of 34 out of the 400 hard coral species found on the Great Barrier Reef. These samples not only serve as a genetic reservoir but also aid in monitoring the detrimental effects of climate change, overfishing, and pollution on coral reefs worldwide.
Scientists warn that a 1.5-degree Celsius increase in temperature could lead to the loss of 70 to 90 percent of the world’s coral reefs, posing a grave threat to marine life and the livelihoods of millions of people reliant on these ecosystems.
Despite ongoing challenges, initiatives like the cryopreservation of coral offer a ray of hope. Recent successful efforts in fertilizing coral larvae from thawed sperm demonstrate the potential for restoring damaged reef systems. However, urgent action is needed to address the underlying causes of coral degradation.
“Reefs possess remarkable resilience, but the window to mitigate the impacts of climate change is rapidly closing,” emphasized Richard Leck, head of oceans at WWF-Australia.
As nations convene for the UN oceans summit in France, the fate of coral reefs hangs in the balance. With global consensus and financial support, there remains a glimmer of hope for the long-term survival of these invaluable marine ecosystems.
© Agence France-Presse