What was done
Using samples of the protective mucus coverings of the corals Montastraea faveolata and Colpophyllia natans from the John Pennekamp Marine Sanctuary south of Key Largo, Florida, the authors examined the effects of ultraviolet (UV) radiation on the microbial communities contained in the coverings.

What was learned
According to the authors, their results comprise "the first evidence of UV-induced DNA damage in the microbial communities of the CSM [coral-surface microlayer] and provide evidence for the direct impact of UV radiation on the surface of corals."

What it means
The authors note that "the potential role of UVR in the global decline of coral reefs is receiving increased attention" and that "increases in environmental levels of UVR, specifically UVB, may lead to changes in reef-building coral abundance."