Evaluation and quantification of the impact of Sunscreen Pollution On Coral – SPOC

The SPOC project implements innovative methods to evaluate the effects of UV filters on corals. In the first phase, we will characterize the responses of the tropical coral Pocillopora damicornis to five UV filters using a non-targeted integrative approach that uses cutting-edge techniques such as metabolomics, transcriptomics, epigenomics and metabarcoding. This will allow us to identify biomarkers of the effects of sunscreens, which will then be used in a targeted approach to assess cellular responses to 31 UV filters approved in Europe. The third phase will examine which filters can cause coral bleaching and whether there are synergistic effects between heat stress and solar filters. Finally, we will test the effectiveness of these new biomarkers in the field by carrying out an experiment of transplanting corals cultivated in the natural environment with concentration gradients of UV filters.

During the first year, the project reached major milestones. The search for the ideal organic solvent to dissolve UV filters was successful, favoring dimethyl sulfoxide (DMSO) for its low toxic effects on coral, even at high concentrations. The exploration of six sites around Tahiti made it possible to collect new coral colonies, updating the stock cultivated in the laboratory since 2015. These new colonies were used for exposures to five UV filters, providing the necessary material for the metabolomic analyzes which are in progress as well as for transcriptomic, epigenomic and metabarcoding analyzes to come in 2024.

The information produced during the SPOC project promotes essential progress in understanding the interactions between corals and UV filters, shedding light on crucial data on the underlying mechanisms. This opens up major opportunities by encouraging the use of environmentally friendly sunscreens and raising awareness of reef preservation issues, which influences consumer choices and guides the industry towards more sustainable practices.

A paper was published in the journal Chemical Research in Toxicology and another in the journal Metabolites. These two papers examine the effects of solar filters on the coral metabolome.

UV filters are widely used for skin protection against cancer. Their impact on corals was poorly investigated but it was shown that octocrylene and several benzophenone filters exert direct detrimental effects on corals, and that other ingredients in sunscreens and cosmetics exacerbate their toxicity. The SPOC project will search for stress biomarkers in corals to introduce a practical reliable tool to quantify coral response to pollutants and evaluate all UV filters allowed in cosmetic products in Europe, while considering the public health importance of sunscreens. Eventually, we will also investigate on the relationship between site contamination and the observed decrease of coral bleaching temperature threshold, and we will qualify wild sites water quality for coral well-being through transplantation experiments and biomarker-based quantification of coral stress.