Coral recruits demonstrate thermal resilience

Area of Science:

• Marine Biology
• Coral Reef Ecology
• Climate Change Adaptation

Background:

• Marine heatwaves are increasing, posing a significant threat to coral reef ecosystems.
• Coral restoration efforts are crucial for supporting native populations against climate change.
• Interspecific hybridization is explored as a method to generate resilient coral stock for restoration.

Purpose of the Study:

• To compare the performance of Acropora kenti and A. loripes hybrid and purebred coral recruits under simulated thermal stress.
• To evaluate the potential of interspecific hybridization for enhancing coral resilience to marine heatwaves.

Main Methods:

• Produced 'KL' hybrids from Acropora kenti eggs and A. loripes sperm; 'LK' hybrids were not produced.
• Exposed purebred and hybrid coral recruits to simulated thermal stress (>12 degree heating weeks over 2 months).
• Assessed performance using survivorship, size, color (bleaching proxy), and photochemical efficiency.

Main Results:

• Neither purebred nor hybrid recruits showed signs of stress under elevated temperatures.
• Purebred Acropora loripes recruits exhibited the best performance under both ambient and elevated conditions.
• KL hybrids performed similarly to the maternal Acropora kenti or not significantly differently from either parent species.

Conclusions:

• Interspecific hybridization showed limitations in boosting coral stock performance against thermal stress.
• Hybrid performance was influenced by maternal Symbiodiniaceae communities, similar to the maternal parent.
• Purebred Acropora loripes may be more suitable for restoration efforts in thermally stressed environments.