Why your sunscreen could be causing coral bleaching and what you can do about it?

2022-07-21

 |  Biodiversity/Conservation

Sunscreen is essential – we know this. It protects our skin from various cancers caused by the sun’s UV rays  and prevents premature aging:everything we don’t want for our skin. We clearly understand the benefits of sunscreen, but what does sunscreen have to do with travel and sustainability?

As travel is ramping up again and summer is upon us, people are heading to the beaches all over the world and slathering on this protective lotion. With this fact in mind, questions surrounding sunscreen may begin to arise. Is every sunscreen the same? Is it all great with no harm to anyone? The answer is no. While sunscreen is great and very important for humans, not all sunscreen is great for aquatic life.

Sunscreen and coral reefs

Between 6000 and 14,000 tons of sunscreen runoff is estimated to be released into coral reef areas each year. This means about 40% of coral reefs around coastlines are at risk of exposure. Beaches and sunscreen go hand-in-hand, so it is safe to say that beaches are swimming with sunscreen runoff from humans. Most chemical sunscreens (meaning they use  chemical filters to absorb UV rays, as opposed to physical sunscreens that reflect UV rays), contain two main chemical filters: oxybenzone and octinoxate. These two chemicals have extreme negative impacts on coral reefs when they are leached into water. 

Photo Credit: Naja Bertolt Jensen (Unsplash)

What happens to coral reefs and other marine life from chemical exposure? 

Coral reefs are very important for overall ocean health. They filter the water, help with nutrient recycling, and provide nitrogen for all aquatic life. Coral can be seen as a giant filtration system for the ocean and helps provide oxygen for all mammals to breathe. This means that when we swim with sunscreen on, the oxybenzone and octinoxate gets filtered by this coral and the chemicals have damaging effects. The nanoparticles from these chemicals accumulate in their tissues and disrupt the coral’s reproduction and growth, which leads to coral bleaching. Coral bleaching happens when there are significant changes to the coral’s environment such as temperature, light or nutrients. These changes can stress the coral and cause them to expel symbiotic algae living in their tissues which results in them turning completely white. . This, along with the effects of climate change, are exacerbating the bleaching process. 

Coral isn’t the only organism that is affected by these sunscreen chemicals. These chemicals  can impair growth and photosynthesis of green algae, induce defects in young muscles, decrease fertility and reproduction in fish, and can bio-accumulate in dolphins and be transferred to their young. 

What is being done about chemical sunscreen runoff? 

Studies have found the effects of sunscreen on coral to be severe and this has led to the banning of these chemicals in Hawaii and Key-West, Florida. These two chemicals were banned in both states on January 1, 2021 to try and prevent the rapid bleaching of coral reefs in the area. 

While the effects of sunscreen on coral is detrimental to ocean health and consequently human health, sunscreen does protect our skin from all the dangers associated with sun damage. Studies have acknowledged the importance of continuing to wear sunscreen, and in making better choices regarding our sunscreen, we can all help protect coral reefs and other aquatic life. 

Photo Credit: Milos Prelevic (Unsplash)

What can YOU do about coral bleaching from sunscreen? 

Luckily there is sunscreen that already exists that is much safer for ocean life. Remember earlier in the article when chemical sunscreen vs physical sunscreen was mentioned? Well, physical sunscreen reflects UV rays and comes in the forms of zinc oxide and titanium dioxide. These are naturally occurring minerals and are often called mineral sunscreens. Since these physical sunscreens use naturally occuring minerals as their active ingredients, they are much safer for the environment, as there is no risk of chemicals leaching into our oceans. 

Even if other countries and regions are slow to ban these harmful chemicals, we can all individually make the  easy switch to  natural physical sunscreen to protect our sensitive skin and limit harm to the planet. 

Cautions with mineral/physical sunscreen 

You will have to do some research on the best mineral sunscreen for you, as some leave a white residue and some contain other chemicals that are still not great for aquatic life. Due to the whitecast/residue that is often left behind with mineral sunscreens, there have been ‘natural sunscreens’ developed with nano-titanium dioxide or nano-zinc oxide that leave little residue behind. These nanoparticles have also been found to lead to coral bleaching, so of course be cautious of the word nano in the ingredients. The rule of thumb is the more simple the ingredients, the better. 

The best natural sunscreen is to wear protective clothing and avoid the sun… but we all know that is not fun when the summer months are so short. The NewYork Times has come up with The Best Reef-Safe Sunscreen and offers other options that are good alternatives. This list is quite thorough and takes into consideration non-nano mineral sunscreen options, as well as the white cast left on different skin colours. 

Making the switch to a less harmful sunscreen may not put a complete stop to coral bleaching, but it is an easy step that we can take in our daily lives to help protect aquatic life and the planet.