Impact of short-term light variability on the photobiology of turbid water corals

Benthic light availability is readily affected by natural drivers of an ecosystem and by anthropogenic-induced stressors. Rapid urbanization in coastal regions can induce light variability for reef-building corals that use photosynthesis as a primary form of energy. However, very little data exists on the photosynthesis of light-limited coral species and their acclimation responses to an additional light variability. This experimental study explored the effects of two contrasting light intensities: high light (HL) (95% increase to in situ light) and low light (LL) (8–10% of in situ light) on three locally dominant coral species. Turbinaria mesenterina, Porites lutea, and Goniopora cellulosa were collected from a 4-m depth from the turbid regions of Pulau Kendi in Northern Peninsular Malaysia. This study documented current photobiological responses of all species and rapid photoacclimation responses only for T. mesenterina in HL treatment. All three species incurred photoinactivation under LL stress; however, T. mesenterina was photosynthetically healthier for an extended period of the experiment. P.lutea recorded partial photoacclimation and non-recovering photoprotectants to both light stresses. While G. cellulosa incurred rapid declines in photosynthetic yields along with no photoacclimation responses. The data obtained for this geographic range of turbid water corals is important as additional light stress from point-source pollutants and global urbanization activities are expected to increase. Improving our understanding of their responses to environmental change will be central to global coral reef conservation efforts andcan be used for effective management practices in targeted coral conservation and rehabilitation approaches for turbid habitats. •Turbinaria mesenterina has a wide range of light tolerance.•Complete photoinactivation was recorded for Goniopora cellulosa.•Greater survivability of Turbinaria mesenterina and Porites lutea is projected at variable light intensity.•Light reductions from anthropogenic activities will further threaten light-limited corals.