Coral Bleaching from Sunscreen Pollution

Coral Bright, Wear White – by Melanie Quan

At the October general meeting of Sustainable Rossmoor, guest speaker Melanie Quan spoke about the harmful effects of sunscreen on coral reefs. White tips on coral pictured above are a reflection of “bleaching” and declining coral health (Photo courtesy of Oregon State University). Melanie’s presentation is below.

Coral bleaching resulting from sunscreen pollution has recently been a significant topic highlighted by the news media. While it is true that sunscreens are a cause of coral bleaching, the problem is multifaceted. As guest speaker Melanie Quan, a sophomore at Las Lomas High School, explained last month, the true impacts of sunscreen pollution are still unknown by a majority of the public. Last summer, she attended a science program called California State Summer School for Mathematics & Science (COSMOS) at UC Santa Cruz and worked to analyze the effects of common active sunscreen ingredients.

Based on the accumulation of studies, results show that common organic chemicals in sunscreen such as oxybenzone, octinoxate, octisilate or butylparaben can exacerbate coral bleaching at concentrations as low as 62 parts per trillion (equivalent to a drop of sunscreen in an Olympic-sized pool!).  Additionally, common inorganic physical barriers in many ‘reef safe’ sunscreens show potential to cause harm by inducing stress through oxidation, making them a less than perfect solution.

Many consumers of ‘reef safe’ sunscreens prefer brands using nano-sized particles or aerosol sprays because they reduce the chalky white look after application. However, these nano-sized particles can be ingested by coral because of their small size, expediting the effects of oxidation and stress on marine life. Thus, while many sunscreen companies have worked to avoid chemicals such as oxybenzone and octinoxate that can rapidly cause coral bleaching, the common alternatives can still cause stress on coral over time.

As conscientious consumers, help us reduce harm to coral ecosystems! By taking note of active ingredients in sunscreens, you can help promote the health and sustainability of coral and marine life. Based on her research, Melanie recommends having titanium dioxide as the only active ingredient in the sunscreens you use. She recommends using non-aerosol, non nano-particle titanium dioxide sunscreens.

This Blog Post written by Melanie Quan.

For more information on coral bleaching, check these web sites from the National Ocean and Atmospheric Administration (NOAA)

What is coral bleaching? When corals are stress by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae living in their tissues, causing them to turn completely white. (https://oceanservice.noaa.gov/facts/coral_bleach.html)

Coral Bleaching — Background (https://www.coral.noaa.gov/education/bleaching-background.html)

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