'Reef-safe' or 'reef-friendly' claims have appeared on the labels of many new sunscreen products. This is due to concerns over organic UV filters harming sea life. Flawed and inconclusive tests have yet to make this connection but a new testing approach could provide the missing link to a clearer understanding.
Research published in Nature Scientific Reports describes the metabolomic profiling of one species of coral to identify stress marker levels and their changes in the presence of UV filters; particularly octocrylene (OC), ethylhexyl salicylate (ES) and benzophenone-3.
Here, the species Pocillopora damicornis expressed increased levels of a known stress steroid in the presence of these sunscreens. Also, according to the article abstract, at levels up to 50 μg/L, OC altered mitochondrial functioning. And at 300 μg/L, ES triggered inflammatory responses. Other tested sunscreen filters did not elicit any responses. [See Letter to the Editor comment on this test concentration.]
For more information, see the full paper.