Optimizing Light Spectrum to Upscale Grow-out of Coral Recruits for Restoration

Principal Investigator/Project Director

Joana Cordeiro Figueiredo

Colleges / Centers

Halmos College of Arts and Sciences


U.S. DOC - National Oceanic and Atmospheric Administration (NOAA)

Start Date



Project Summary: This project aims to determine the optimal light spectra under which to rear sensitive coral recruits in order to rapidly and effectively upscale production of genetically-diverse corals for restoration. A major constraint to the sexual propagation of reef-building corals for restoration is the time needed for the recruit grow-out. It is already known that early settlers require low irradiance. However, once they reach 8-12 weeks old and are fully infected with their algal endosymbionts, their algal symbionts require higher light irradiance to meet the recruit’s energetic demands. Artificial lights have been used by hobbyists for maintaining and growing corals in captivity. Preset lighting spectra even exist to assist with aquarium-raised corals. What remains unclear is the optimal light spectrum needed to maximize the survival and growth of early settlers before, during, and immediately after the uptake of their algal endosymbionts. Here we propose a set of coordinated and parallel studies across four land-based coral nursery facilities to test and compare the impact of different light treatments on at least two reef-building coral species endemic to Florida. Conducting these experiments in different facilities, while statistically controlling for its effect, will also allow us to collect microbiome samples for assessing differential microbiome profiles within and among facilities and across light spectrum treatments. Sexually propagating corals builds resilience by producing genetically diverse corals, some potentially more stress-tolerant as their parents are survivors of recurrent stress events like disease outbreaks and bleaching. Eliminating or reducing bottlenecks associated with mass production of corals in land-based nurseries would provide a key contribution to effectively upscaling the number and diversity of corals used for restoration. With several of Florida’s most important reef-building stony coral species experiencing persistent recruitment failure, there have been increased investments in the sexual propagation of corals for active restoration. These findings will be relevant to anyone sexually propagating corals and rearing sexual recruits in a land-based setting that utilizes artificial lights, including those facilities part of the AZA Florida Reef Tract Rescue Project.

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