PT - JOURNAL ARTICLE AU - Tomás López-Londoño AU - Claudia T. Galindo-Martínez AU - Kelly Gómez-Campo AU - Luis A. González-Guerrero AU - Sofia Roitman AU - F. Joseph Pollock AU - Valeria Pizarro AU - Mateo López-Victoria AU - Mónica Medina AU - Roberto Iglesias-Prieto TI - Physiological and ecological consequences of the water optical properties degradation on reef corals AID - 10.1101/2021.02.18.431834 DP - 2021 Jan 01 TA - bioRxiv PG - 2021.02.18.431834 4099 - http://biorxiv.org/content/early/2021/02/18/2021.02.18.431834.short 4100 - http://biorxiv.org/content/early/2021/02/18/2021.02.18.431834.full AB - Degradation of water optical properties due to anthropogenic disturbances is a common phenomenon in coastal waters globally. Although this condition is associated with multiple drivers that affect corals health in multiple ways, its effect on light availability and photosynthetic energy acquisition has been largely neglected. Here, we describe how declining the water optical quality in a coastal reef exposed to a turbid plume of water originating from a man-made channel compromise the functionality of the keystone coral species Orbicella faveolata. We found highly variable water optical conditions with significant effects on the light quantity and quality available for corals. Reduction of light penetration into the water column elicits the development of low-light phenotypes close to theoretical limits of photoacclimation despite their occurrence at shallow depths. Predicted photosynthetic energy depletion with increasing depth is associated with patterns of colony mortality and contraction of the habitable space for the population. A numerical model illustrates the potential effect the progressive degradation of water optical properties on the gradual mortality and population decline of O. faveolata. Our findings suggest that preserving the water optical properties seeking to maximize light penetration into the water column may have an extraordinary impact on coral reefs conservation, mostly toward the deeper portions of reefs.Competing Interest StatementThe authors have declared no competing interest.