Science - May 28, 2018

Sunscreens could damage Bonaire coral reef

Text:
Roelof Kleis

Are the coral reefs near Bonaire suffering because of sunscreens? Wageningen biologists are investigating how harmful the use of these lotions is.

The idea that coral could not withstand sunscreens seems absurd at first. After all, is the ocean not so vast that any potentially harmful substances would be diluted to a point where no effect could be expected? ‘That’s what I initially thought as well’ says Diana Slijkerman of Wageningen Marine Research. But measurements have shown that an effect is indeed noticeable.

Two years ago, Slijkerman was asked by Bonaire whether suntan lotions are harmful for the local coral reefs. The motive was a scientific study that showed some UV filters can harm coral. Slijkerman had samples of water taken from a popular touristic bay sent to Wageningen and started analysing them. ‘The result: yes, the substances are present in concentrations for which we cannot exclude effects.’

The primary substance concerned is oxybenzone, which is added to products to protect from ultraviolet light. But what can be good for humans turns out to be bad for corals. Depending on the concentration, the substance can bleach coral, which means that the algae living in the coral are expelled. ‘Oxybenzone has a disruptive effect on the development of the larval stage of coral, among other things, and makes algae in the coral more susceptible to infections’, Slijkerman elaborates.

De eerste resultaten schreeuwen om vervolgonderzoek
Ronald Osinga

As such, the effect of oxybenzone is very similar to the increase in temperature due to climate change, adds coral researcher Ronald Osinga. For Slijkerman’s project, he performs laboratory experiments into the effects of oxybenzone, water temperature and the combination of the two stress factors on two species of coral. ‘The first results are screaming for follow-up research’, Osinga reveals. This follow-up is currently being set up.

In the meantime, Slijkerman has started a campaign together with the local sustainability organisation Boneiru Duradero. The campaign, which is supported by the World Wide Fund for Nature, is meant to raise the awareness of tourists visiting the island regarding the consequences of the use of certain sunscreens. According to Slijkerman, surveys among the tourists have shown that mainly American tourists use lotions containing oxybenzone. The tourists arrive by cruise liner and bring the products from home.

The political involvement shows how seriously the island is approaching the issue. The Island Council of Bonaire recently passed a motion that should lead to a prohibition of products containing oxybenzone. However, such a prohibition will not be effective before 2021. Furthermore, considering the results of the survey, Slijkerman also doubts whether it will make a difference. Most tourists buy their sunscreen at home.

She therefore has more faith in involving the cruise sector in the development of an effective policy over the next few years. For example by informing tourists about the possible effects of some sunscreens before they arrive, but also through research into possible alternatives. According to Slijkerman, most suntan lotions sold in Europe do not contain oxybenzone.

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