On World Reef Day, let’s consider sunscreen…

You may have heard that sunscreen is bad for coral reefs, but do you know what it actually does once in the ocean?

Wildlife Blogger of the Year 2018 Finalist and Marine Biologist Hannah Rudd shares some sunscreen science and tips for minimising damage from sunscreen.

Coral reefs are often romantically described as the tropical rainforests of the sea, buzzing with life like an underwater metropolis. Home to 25% of known marine life, these ocean ecosystems cover around 0.1% of the planets surface.

With staggering levels of biodiversity, it’s about time that we celebrated these ecosystems and the services they provide us with – and 2019 is finally that year, with the first World Reef Day taking place on 1st June 2019.

Thanks to lots of educational efforts, many are aware of the disastrous impacts of climate change devastating our reefs globally via increasing sea surface temperatures and ocean acidification.

But what about sunscreen? Every time someone slathered in chemicals enters the ocean, whether that’s sunscreen or other beauty products like moisturisers, residues seep into the marine environment.

We currently don’t know exactly how much sunscreen enters our oceans annually, but it’s estimated that between 6,000 – 14,000 tons of sunscreen is released into areas with coral reefs each year – think Hawaii, the Caribbean, the Maldives and other tropical paradise holiday destinations.

Now you would be forgiven for thinking “What harm can my sunscreen do? It’s literally just a drop in the ocean”. But it seems a drop is all that’s needed to endanger our marine life.

Oxybenzone is the synthetic chemical component that appears to be doing all the dirty work. It’s toxic to corals, algae, sea urchins, fish and mammals.

In fact, oxybenzone has even been shown to result in gender shifts within some fish species, causing males to develop female attributes and females to undergo reduced egg production.

A scientific study in 2015 identified that their study locations contained 1-10% of the UV filter oxybenzone with a staggering 40% of coastal reefs estimated to be at risk of exposure to oxybenzone.

What does oxybenzone do to corals?

A 2016 study published in the journal Archives of Environmental Contamination and Toxicology unveiled that oxybenzone has four main implications for corals:

  • Increased susceptibility to coral bleaching
  • Damage to DNA (known as genotoxicity)
  • Endocrine disruption, leading to abnormal skeleton growth
  • Deformities in juvenile corals

What about other marine life?

Well, it’s not surprising that anthropogenic substances can have shocking impacts on the natural world, with this infographic from the National Oceanographic and Atmospheric Administration (NOAA) summing it up nicely…

Infographic from the National Oceanographic and Atmospheric Administration (NOAA)
Infographic from the National Oceanographic and Atmospheric Administration (NOAA).

 How can I protect my skin and protect corals?

  1. Cover Up First – Do you really need to wear sunscreen? Check the UV index to see sun protection recommendations. Put on a hat, sunglasses and items of clothing like t-shirts first to increase your sun protection – this can reduce the amount of sunscreen you need by around 90%.
  2. The Safe Sunscreen Council When purchasing your sunscreen take a quick look at this website first. It lists all of the companies that comply with the current scientific understanding and requirements for a reef-safe sunscreen.
  3. Check The Ingredients – Look for products with mineral sunblocks containing zinc oxide and titanium dioxide which are “non-nano”. Don’t know where to start? The Nano Tech Project website is an ideal place to begin your search.

The jury is still out on the level of impact oxybenzone and other synthetic chemicals have on the worlds coral reefs, with more research needing to be done to fully understand the problem.

Regardless, I believe it’s always worth invoking the precautionary principle and if there are reef-safe sunscreen alternatives that are not only thought to be better for coral health, but also human health, then why wouldn’t you choose that option?

For more information, please see this video from the Reefs At Risk project – the state of Hawaii has since banned these sunscreens from 2021.

This post was originally published on Hannah Rudd. Hannah is a Marine Biologist, Writer and Science Communicator currently pursuing an MSc in Marine Environmental Management at the University of York