Master of Science
Joana Figueiredo, Ph.D.
Nicole D. Fogarty, Ph.D.
D. Abigail Renegar, Ph.D.
Direct and indirect anthropogenic stressors have led to a global decline of coral populations. Coral restoration aims to mitigate this loss and facilitate reef recovery. In particular, the sexual propagation of corals ex situ allows for the production and outplant of genetically diverse coral recruits on the reef. However, optimization at ex situ coral nurseries is required to scale-up production. This project aims to investigate and develop methods that reduce the duration of grow-out ex situ by determining the optimal light spectrum under which to rear for sexual recruits of the tropical scleractinian coral species Pseudodiploria strigosa and P. clivosa. Newly-settled corals of these species were reared under dim light (µmol photons m-2 s-1) and, after 4 weeks, shifted to one of three light spectra: blue-shifted spectrum produced by an LED light with a reef-depth light irradiance, reef depth spectrum produced by an LED light, or near surface depth light spectrum produced by natural sunlight with reef-depth irradiance levels achieved by using shade cloths. The three treatments were replicated in two tanks where survival and growth were quantified weekly from five to fourteen weeks post-settlement. Pseudodiploria strigosa demonstrated significantly higher survival and growth than P. clivosa, which may be due to their greater size at the time of settlement. Corals under LED lights exhibited faster growth rates than corals exposed to sunlight. The results suggest that light spectrum is an important factor in coral growth, and LED blue-shifted light spectrum may be a more suitable spectrum for coral grow-out 5 weeks after settlement. The manipulation of light spectrum during coral grow-out can reduce the time required at the ex situ nursery before outplanting and/or increase the size of the corals available for outplanting, thereby decreasing chances of mortality due to predation and overgrowth.
Daisy N. Ponce. 2023. Optimization of Light Spectrum During Coral Grow-out. Master's thesis. Nova Southeastern University. Retrieved from NSUWorks, . (144)