Sunscreen is crucial in protecting people from the harmful UV rays that can cause skin cancer and other problems. Although it has been proven to protect people from sunburns, many coral reefs are being killed by it. New research has shown that sunscreen can be deadly for marine life.
Since years, it has been well known that sunscreens containing the chemical oxybenzone are likely to be the cause of coral reef damage. Although the chemical blocks UV rays from the human skin well, once it's in water, it can cause damage to other life forms. This is why certain sunscreen formulas have been banned in reef-rich areas like Hawai'i and the U.S Virgin Islands.
It was not known how the chemical became so toxic to marine life. There are no safer sunscreen options.
This is the information gap that a new study published in Science on Thursday sought to close.
The researchers placed 21 anemones into seawater, and then covered five of them with a cover that blocks UV light. This is because oxybenzone can interact with ultraviolet light. The animals were then given 2 mg of oxybenzone for every liter of seawater.
Researchers explained that annemones are translucent, similar to corals. If oxybenzone was acting as a phototoxin the UV rays hitting one group of animals would trigger a chemical reaction, killing them, while the dark group would live.
That's exactly what happened.
It took only six days for the first anemone to die after it had been exposed to UV light and then left to die in the UV light. Ten days later, all the anemones covered in light were dead. However, the ones that were not exposed to the UV rays survived.
Researchers discovered that anemones automatically treat oxybenzone like a foreign substance. This kickstarted metabolic processes that changed the chemical composition of oxybenzone. Although this is something that animals and plants do to make toxic substances less toxic, in this case it made the chemical compound of the oxybenzone deadly.
It retains the UV-light energy and initiates a series rapid chemical reactions that cause cell damage. Researchers found that the anemones transform oxybenzone from a harmless, easily-extracted molecule into a powerful, sunlight-activated toxin.
Researchers discovered that some forms of marine life are protected by built-in protection. They found that the phototoxins were stored within the algae living in mushroom corals when they did a second experiment. It is believed that the coral would have suffered the same fate without the algae.
Scientists ran another test on anemones without any algae and found that they died twice as fast as the ones with the algae. They also had nearly three times the amount of phototoxins in their cells than the anemones with the algae.
Although the discovery of the benefits that algae can offer is encouraging, it also comes at a critical time when coral reefs are being destroyed by bleaching. Coral bleaching is when algae is removed from corals. This leaves marine animals without primary food source and makes them more vulnerable to disease.
Researchers warn that coral reefs could be at risk from "intolerable levels of thermal stress" as the Earth warms to 1.5 degrees Celsius. This is due to extreme heat events, which can lead coral bleaching.
Without better sunscreen formulas, a summer dip into the ocean could only make matters worse for vital coral reef ecosystems. This is especially true given the amount of sunscreen in the ocean.
According to the National Park Service, coral reefs are exposed to between 4,000 and 6 000 tons of sunscreen each year. The National Park Service stated that 90% of tourists who dive or snorkel in the waters around 10% of the world's coral reefs are doing so. It's these beautiful and popular underwater scenes that bear the brunt of the toxic effects.
Djordje Vuckovic, study's lead author, stated in a statement that ecotourism meant to protect coral reefs would actually be exacerbating the decline.
Many sunscreens that claim to be safer for marine life contain chemicals similar to oxybenzone. This could mean they are adding to the problem rather than solving it. The latest research is a crucial piece of the puzzle. With summer fast approaching, and ongoing efforts to reduce the impact of climate change, the findings of the researchers could lead to a sunscreen formula that protects all life forms.
