UC Santa Barbara

Reef-building corals exhibit remarkable regenerative capabilities, enabling recovery from a range of physical disturbances. However, coral regeneration can incur significant energetic costs leading to tradeoffs with growth or reproduction. This physiological constraint may be exacerbated by stressful conditions, such as warming that can disrupt nutrient acquisition by algal endosymbionts (Symbiodinaceae). In this study, I investigate the role of temperature (27.9℃ & 29.5℃) and injury (abrasion & fragmentation) on energy acquisition, allocation, and utilization during regeneration. To explore these dynamics, I conducted a controlled mesocosm experiment in Moorea, French Polynesia, using a prominent reef building coral, Acropora pulchra. Overall, regeneration was achieved in 92% of corals 19 days post-injury, however tissue regeneration was faster in abraded corals. Interestingly, I found no significant effects of injury or temperature on growth rates of A. pulchra. This may be explained by a limited increase in respiration with significant increases in productivity (daily P:R) during regeneration. These results support the use of genus Acropora as an ideal candidate for coral restoration due to their capacity to rapidly regenerate from physical damage. Although I found no evidence for a physiological tradeoff between growth and regeneration, these results highlight the importance of a broader investigation of physiological tradeoffs (or a lack thereof) as they apply to coral restoration efforts. As coral restoration practitioners aim to scale up production of propagated corals in land-based facilities, it is crucial to assess regenerative capacity and anticipate physiological tradeoffs for injured coral fragments under future warming conditions.