Sunscreens cause coral bleaching by promoting viral infections.
BACKGROUND
Coral bleaching (i.e., the release of coral symbiotic zooxanthellae) has negative impacts on biodiversity and functioning of reef ecosystems and their production of goods and services. This increasing world-wide phenomenon is associated with temperature anomalies, high irradiance, pollution, and bacterial diseases. Recently, it has been demonstrated that personal care products, including sunscreens, have an impact on aquatic organisms similar to that of other contaminants.


OBJECTIVE
Our goal was to evaluate the potential impact of sunscreen ingredients on hard corals and their symbiotic algae.


METHODS
In situ and laboratory experiments were conducted in several tropical regions (the Atlantic, Indian, and Pacific Oceans, and the Red Sea) by supplementing coral branches with aliquots of sunscreens and common ultraviolet filters contained in sunscreen formula. Zooxanthellae were checked for viral infection by epifluorescence and transmission electron microscopy analyses.


RESULTS
Sunscreens cause the rapid and complete bleaching of hard corals, even at extremely low concentrations. The effect of sunscreens is due to organic ultraviolet filters, which are able to induce the lytic viral cycle in symbiotic zooxanthellae with latent infections.


CONCLUSIONS
We conclude that sunscreens, by promoting viral infection, potentially play an important role in coral bleaching in areas prone to high levels of recreational use by humans.
Danovaro
Roberto
R
Department of Marine Sciences, Faculty of Science, Polytechnic University of the Marche, Via Brecce Bianche, 60131 Ancona, Italy. r.danovaro@univpm.it
Bongiorni
Lucia
L
Corinaldesi
Cinzia
C
Giovannelli
Donato
D
Damiani
Elisabetta
E
Astolfi
Paola
P
Greci
Lucedio
L
Pusceddu
Antonio
A
D000818:Animals; D037421:Anthozoa / Q000187:drug effects* / Q000821:virology*; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D056890:Eukaryota / Q000187:drug effects*; D009792:Oceans and Seas; D013473:Sunscreening Agents / Q000633:toxicity*; D013559:Symbiosis
D013473:Sunscreening Agents