Reviving Coral Reefs: IVF Colonies Thrive Despite Record Heatwaves
In a groundbreaking study, scientists have discovered that young corals bred using in vitro fertilisation (IVF) have shown remarkable resilience in the face of last year’s record marine heatwave. While older corals struggled to survive, the IVF-created colonies planted in reefs across the US, Mexico, and the Caribbean have defied expectations.
The study found that an impressive 90% of the young IVF-created corals surveyed remained healthy and vibrant, maintaining their symbiotic relationship with algae that provide them with essential nutrients. In contrast, only a quarter of the older non-IVF corals were able to withstand the heat stress, with many succumbing to bleaching or death.
Dr. Margaret Miller, the lead author of the study and research director at Secore International, a reef conservation organization, expressed her surprise at the results. She noted that the data revealed an extreme pattern of survival among the IVF-created corals, despite the challenging conditions of the heatwave.
The young corals were bred using a specialized IVF technique developed by Secore over the past five years. Coral spawn collected by divers was used to fertilize eggs in a laboratory setting, resulting in the birth of baby corals that were then transplanted onto reefs across the Caribbean to establish new colonies.
Enhancing Genetic Diversity Through IVF
Unlike traditional coral restoration methods that focus on fragmenting existing corals, IVF breeding offers a unique advantage by increasing genetic diversity among the new colonies. This diversity gives the corals a better chance of adapting to rising ocean temperatures over time, as natural selection in the reef environment favors the most resilient individuals.
The 771 young corals included in the study, a fraction of the thousands bred annually by Secore and its partners, inhabit restored reefs in various locations, including Mexico, the Dominican Republic, the US Virgin Islands, and the Dutch Caribbean territories of Bonaire and Curaçao. These young corals were compared to older elkhorn corals at Sombrero reef in the Dominican Republic, where the devastating effects of white band disease in the 1980s led to a decline in the population.
Maria Villalpando, a researcher at the Dominican Foundation for Marine Studies (Fundemar), observed that the young elkhorn corals bred through IVF remained healthy and vibrant during the peak heat stress, while the older corals suffered significant losses. This disparity highlights the potential of IVF breeding to create more resilient coral populations in the face of climate change.
Challenges and Opportunities for Coral Restoration
While the success of IVF-created corals in surviving heatwaves is promising, researchers acknowledge that there are still challenges ahead. The long-term heat tolerance of these young corals remains uncertain, as previous studies suggest that they may become less resilient as they age.
Dr. Miller emphasized the importance of addressing the underlying causes of global climate change to ensure the survival of coral reefs in the future. However, she also stressed the value of supplementing coral populations through IVF breeding as a temporary solution to buy time for these vulnerable ecosystems.
In Australia, bleaching events have occurred every other year for the past six years, while in the Caribbean, they are occurring approximately every five years. Even if coral colonies survive these events, their reproductive capacity may be compromised for several years, further endangering their long-term survival.
In conclusion, the success of IVF-created coral colonies in withstanding heat stress offers hope for the future of reef conservation. By enhancing genetic diversity and resilience, these young corals represent a valuable tool in the fight against climate change-induced coral bleaching. As researchers continue to study and monitor these colonies, they hope to gain valuable insights into the mechanisms underlying their heat tolerance, paving the way for more effective coral restoration efforts in the years to come.
