Photobiology and growth of leather coral Sarcophyton cf. glaucum fragments stocked under low light in a recirculated system

Corals are considered promising sources of new natural products and their culture, under controlled conditions, may be the solution for a sustainable and continuous supply of their biomass. Light is of utmost importance for ex situ production of corals harboring zooxanthellae, as their photosynthetic performance can significantly affect coral physiology and growth. The present study aimed to evaluate the effect of three light Photosynthetically Active Radiation (PAR) treatments (50, 80 and 120μmolquantam-2s-1) promoted by 150W (10,000K) Hydrargyrum Quartz Iodide (HQI) lamps on the photobiology, survival and growth of the soft coral Sarcophyton cf. glaucum produced ex situ in recirculated systems. After 60days of experiment coral fragments exposed to 50μmolquantam-2s-1presented significantly higher values of Fv/Fmand Normalized Difference Vegetation Index, zooxanthellae density and most photosynthetic pigment concentrations, when compared with corals under higher PAR values. No significant differences were found on coral fragment survival and growth. S. cf. glaucum production under low PAR intensities can effectively reduce the production costs with electrical power, and simultaneously maximize the production of photosynthetic pigments or bioactive compounds mediated by the zooxanthellae.Rui J. M. Rocha was supported by a PhD scholarship (SFRH/BD/46675/2008) funded by Fundação para a Ciência e Tecnologia, Portugal (QREN–POPH — Type 4.1 — Advanced Training, subsidized by the European Social Fund and national funds MCTES). The authors thank the anonymous reviewers for their insightful comments on a previous version of our work.publishe