What are corals and how does sunscreen affect them?

For millions of years, corals have been growing to form the bedrock of life in the ocean. In only one generation, we have seen a large increase in the pollution of our oceans from fertilizers to plastic and trash causing ocean acidification. As well as a large increase in chemical products l such as sunscreen, that are washed off into the oceans from swimming and showering. These factors have lead to a dramatic increase of coral bleaching. Prolonged bleaching events in coral can lead to death in these animals. 

Coral reefs are large underwater structures composed of the skeletons of colonial marine invertebrates called coral. There are two kind of coral, hard coral and soft coral. The coral specs that build reefs are known as “hard” coral, because they extract calcium carbonate from the seawater. Using the calcium to create hard exoskeletons that protect their soft bodies. The other kind of coral is known as “soft” coral. They are the coral that resemble plants like the sea fan and sea whips. Each individual coral is known as a coral polyp, growing their own exoskeleton very slowly.

Corals grow at approximately 1-2 cm per year, meaning the growth process is very slow but the bleaching process can happen very fast.

While they make up less than 0.1% of the ocean’s floor, corals the cities of the ocean, and provide the food source for over a quarter of marine life.

The correlation between the increase in chemical sunscreen use in the 1980’s, along with the rising temperatures and increased pollution of the oceans, aided in the first bleaching event that was discovered during the strong El Niño in 1983.

As the rise of oxybenzone use in sunscreen during the 1980’s, corals have begun to decline. Over 1 million pounds of oxybenzone is imported into the United States yearly.  Over 28 million pounds of sunscreen enters the areas around reefs each year, many of these reefs being highly concentrated tourist attractions.  NOAA estimates that 90 of snorkeling/diving tourists are concentrated on 10% of the world’s reefs.

Oxybenzone and Octinoxate are two chemical filters that are very harmful to Corals. As small as one drop in 6.5 Olympic size swimming pools, are enough to bleach or kill coral. Oxybenzone is shown to disrupt coral reproduction, damages coral DNA, and causes coral bleaching. Octinoxate has shown to also cause coral bleaching.

When we lose our coral, billions of sea life species will suffer, and millions of people will lose their most significant food source. In a great sense, there is no single animal that humans rely on more than corals.

But now, globally, less than 50% of corals remain.


There is no reason for us to rely on chemical-base sunscreens. Banning the these known harmful chemicals from sunscreens, can immediately help coral recover. A brief bleaching event doesn’t mean that the coral is dead, but a prolonged and severer bleaching event can cause disease and starvation. 

Hawaii has always been a leader in ocean safety and environmental consciousness. It became the first state to ban oxybenzone and octinoxate in May of 2018. The Florida Keys have sadly rejected the proposed ban on chemical sunscreens, in a ruling that came early this year in 2020. The Florida Keys were able to make in impact with the community in their ability to educate the public about this important topic. There’ve now been many businesses that have chosen to not sell chemical sunscreens and have switched to mineral based products. The US Virgin Islands have also recently voted to ban the possession, sale, and distribution of chemical sunscreens. The ban went into effect March 30th, 2020. 

It has been proven that when bans are implemented, as has been done in Hawaii and Palau, the corals have an opportunity to regain health and continue to support marine life for years to come.

The best thing we can do as a consumer and protector of our oceans and waterways is to read the labels and ingredients in the products that we buy in a day to day basis.  Make sure that when a product clams to be “Reef Safe” or “Reef Friendly” it really is. If a sunscreen has other chemical filters such as octocrylene or octinoxate, they aren’t reef safe, they are simply “Oxybenzone Free” and that’s a big difference!  

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