Corals and their photosymbionts experience inherent changes in light along depth gradients, leading them to have evolved several well-investigated photoacclimation strategies. As coral calcification is influenced by light (a process described as LEC-“light enhanced calcification”), studies have sought to determine the link between photosynthesis and calcification, but many puzzling aspects still persist. Here we examine the physiology of Euphyllia paradivisa, a coral species found at a wide range of depths but that is strictly mesophotic...