[Coral-List] sunscreen and corals

Gene Shinn eshinn at marine.usf.edu
Fri May 30 15:01:59 EDT 2008

Dear Kee Alfian, Your question re: sunscreen 
included, "anybody got any comment." Well yes I 
do. I obtained the original paper by Danavaro et 
al., some months ago. I did not understand the 
chemistry so I sent it to a friend who 
understands that kind of stuff far better than I. 
He became very animated and brings it up every 
time we talk. His became interested because for 
his PhD he worked on pesticides concentrated in 
surface films (think ocean slicks) and he has 
also smelled the perfume when the cattle boats 
unload dozens of snorkelers on the reef. This 
fellow went on to head the US EPA pesticide 
toxicology lab for ten years and then did ten 
years on the hill doing EPA policy stuff before 
retiring to Key West, Florida. He is also a 
Fellow of the American Academy of Environmental 
Medicine. We have been collaborating on the 
African Dust issue (mainly public health aspects) 
for several years. With that said, he was very 
impressed with the sun screen research article. 
The basic story is that the zooxanthelle contain 
latent viruses (for example when you get shingles 
it is caused by the latent chicken pox virus that 
remains in your body for the rest of your life.) 
In the sunscreen tests the corals were placed in 
2 L bags of sea water with sunscreen (I don't 
recall the amount). The sunscreen stimulated the 
latent virus in the zooxanthelle to proliferate 
causing them to be ejected by the coral. This did 
not happen with the controls that did not contain 
sunscreen. The virus that was present in the 
sunscreen bleached corals were not present in the 
controls. The control corals did not bleach. His 
main point when we discussed it is that this is 
not a toxicity response but rather an immune 
response. An immune response is something much 
more subtle than a toxicity reaction. Being a 
chemical oceanographer by training he verified 
that the chemistry and the various compounds used 
were correct. The main issue is volume. How can 
there be enough sunscreen to cause such a 
reaction. It is a large ocean after all.
     His thought on the volume issue was that 
sunscreen is likely to be incorporated and 
concentrated in the surface slicks. In his 
pesticide work he found many years ago that 
pesticides were often concentrated there by a 
factor of a million or more over what is in the 
water column. Now imagine a sunscreen 
contaminated slick passing over a coral reef 
where there is enhanced wave mixing. Could 
concentrated sunscreen oil be released in the 
wave-mixed reef waters? He says this certainly 
happens with pesticides (and African dust for 
that matter). Also an immune reaction would not 
require a large concentration. Once started the 
virus could continue to proliferate when the 
sunscreen is long gone. So, I don't necessarily 
buy in to all this but I have seen the slicks of 
suntan crème and smelled the fragrance of coconut 
on some of my favorite reefs when the cattle 
boats unloaded. I suggest some more 
experimentation is in order. Go for it. Gene


No Rocks, No Water, No Ecosystem (EAS)
------------------------------------ -----------------------------------
E. A. Shinn, Courtesy Professor
University of South Florida
Marine Science Center (room 204)
140 Seventh Avenue South
St. Petersburg, FL 33701
<eshinn at marine.usf.edu>
Tel 727 

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