The objective of this study was to test the effect of light (sand and CCA) and dark (macroalgae) substrata on the photosynthetic efficiency of coral tissues adjacent to these surfaces. The study was motivated by the conspicuous effects of macroalgae in “darkening” the submarine light fields of reefs, an effect we demonstrated through spectral analysis of the light microenvironment using an underwater spectrophotometer.

Climate warming is predicted to have pronounced effects on biodiversity, particularly the biogeography of organisms, such that species’ range distributions should contract at warmer and expand at cooler range margins, via influences on population-demographic processes, resulting in overall higher latitudinal or elevational displacement of individuals.