Data from: Acclimatization of symbiotic corals to mesophotic light environments through wavelength transformation by fluorescent protein pigments

The depth distribution of reef-building corals exposes their
photosynthetic symbionts of the genus Symbiodinium to extreme gradients in
the intensity and spectral quality of the ambient light environment.
Characterizing the mechanisms used by the coral holobiont to respond to
the low intensity and reduced spectral composition of the light
environment in deeper reefs (greater than 20 m) is fundamental to our
understanding of the functioning and structure of reefs across depth
gradients. Here, we demonstrate that host pigments, specifically
photoconvertible red fluorescent proteins (pcRFPs), can promote coral
adaptation/acclimatization to deeper-water light environments by
transforming the prevalent blue light into orange-red light, which can
penetrate deeper within zooxanthellae-containing tissues; this facilitates
a more homogeneous distribution of photons across symbiont communities.
The ecological importance of pcRFPs in deeper reefs is supported by the
increasing proportion of red fluorescent corals with depth (measured down
to 45 m) and increased survival of colour morphs with strong expression of
pcRFPs in long-term light manipulation experiments. In addition to
screening by host pigments from high light intensities in shallow water,
the spectral transformation observed in deeper-water corals highlights the
importance of GFP-like protein expression as an ecological mechanism to
support the functioning of the coral–Symbiodinium association across steep
environmental gradients.