MEPS - Vol. 313 - Feature article

The scleractinian coral Turbinaria mesenterina is abundant on inshore reefs: conspicuous pale patches may develop on the surface of colonies exposed to excessive light. Photo: Dr. Andrew Baird, ARC Centre for Excellence for Coral Reef Studies, Townsville, Australia

Hoogenboom MO, Anthony KRN, Connolly SR


Energetic cost of photoinhibition in corals


Exposure to excessive light may damage the symbiotic algae (zooxanthellae) that live within coral tissue, thereby making corals less efficient at converting light into energy (a phenomenon called photoinhibition). In this study, we investigate how much photoinhibition reduces the energy budget of corals in different light environments, using the coral Turbinaria mesenterina as a model organism. Results indicated that daily costs of photoinhibition are negligible under field conditions, contrary to expectations based on previous studies. However, repeated exposure to excessive light (simulating a shift to lower tides and/or clearer water) leads to reduced energy acquisition of colonies. Thus, when low tides combine with clear water and bright sunshine, the ability of coral colonies to meet daily energy requirements is reduced. Therefore, photoinhibition influences the upper limit of the depth distribution of scleractinian corals.


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