Ultraviolet Radiation Effects on Coral Reef Ecosystems

Ultraviolet radiation (UVR) from solar output penetrates shallow reef waters and directly influences the health and function of reef‐building corals. UV-A and UV-B wavelengths can damage cellular components in both the coral animal and its symbiotic algae, generating reactive oxygen species that disrupt photosynthesis, impair nutrient exchange and compromise skeletal growth. Although ambient UVR is essential for algal photosynthesis, higher intensities elevate bleaching risk, reduce calcification rates and alter microbial communities. Species and population‐level variation in pigmentation, sunscreen compounds and depth distribution mediate sensitivity, while the combined effects of UVR with warming, acidification or pollution tend to amplify physiological stress. Understanding these interactions is critical for predicting reef resilience under future climate scenarios and for developing mitigation strategies such as shading, selective breeding or water‐quality management.

Research from Nature Portfolio

Recent studies have uncovered an evolutionarily conserved role for c-Jun N-terminal kinase (JNK) in the early cellular response of corals to UVR and heat stress. Activation of the JNK pathway suppresses UV-induced reactive oxygen species accumulation in coral tissues, preserving photosynthetic machinery and reducing bleaching. Inhibition of JNK leads to elevated oxidative stress, symbiont loss and cell death, highlighting a molecular target for bolstering coral tolerance to combined abiotic stressors.

Ultraviolet Radiation Effects on Coral Reef Ecosystems publication trend

The graph below shows the total number of articles in ultraviolet radiation effects on coral reef ecosystems across all publications each year (not limited to Nature Index journals).

Technical terms

Ultraviolet-A (UV-A): Wavelengths between 315 and 400 nm that penetrate deeper waters and contribute to photoacclimation.

Ultraviolet-B (UV-B): Shorter wavelengths (280–315 nm) that cause DNA damage, generate reactive oxygen species and drive bleaching.

Reactive Oxygen Species (ROS): Highly reactive molecules formed under stress that can oxidise cellular lipids, proteins and DNA.

Zooxanthellae: Photosynthetic dinoflagellate symbionts within coral tissues that provide energy via photosynthesis.

Photoacclimation: Physiological adjustment of the photosynthetic apparatus to varying light intensities, enhancing tolerance to UVR.

References

1. The interactive impacts of a constant reef stressor, ultraviolet radiation, with environmental stressors on coral physiology. The Science of The Total Environment (2023).
2. The c-Jun N-terminal kinase prevents oxidative stress induced by UV and thermal stresses in corals and human cells. Scientific Reports (2017).
3. Unraveling the Seasonality of UV Exposure in Reef Waters of a Rapidly Warming (Sub-)tropical Sea. Frontiers in Marine Science (2020).
4. Differential susceptibility of Red Sea Pocilloporidae corals to UVB highlights photoacclimation potential. Frontiers in Marine Science (2023).