Coral bleaching occurs when heat stress causes polyps to expel their symbiotic algae (zooxanthellae). Over repeated mild stress events, surviving colonies can shift their symbiont community and heat tolerance upward — a form of ecological/physiological adaptive learning.
stress = max(0, T − T_tolerance)
health' = health − k₁·stress + k₂·nutrients
T_tolerance' += adaptRate · stress · dt · 0.02
- Sea temperature — thermal stress driving bleaching; sustained rises above tolerance whiten colonies.
- Adaptation rate — how fast surviving coral raises its heat-tolerance threshold after each stress exposure.
- Nutrient availability — food supply aiding recovery and regrowth of bleached coral.
- Genotype — heat-resilient stock starts with a higher baseline tolerance, illustrating assisted-evolution reef restoration.
Real-world use: reef managers select and outplant heat-tolerant coral genotypes and monitor bleaching thresholds to build climate resilience into restoration projects.