Scientists fear ‘zombie’ phenomenon may ravage Hawaiian waters: ‘The people who lived there have always wondered’

Leo Collis
Sat, January 27, 2024



Scientists are growing concerned that chemicals leached into the ocean from beach showers could be doing serious damage to one of the most vulnerable marine species.
What’s happening?

A report on Undark described how Craig Downs, an ecotoxicologist and the executive director of Haereticus Environmental Laboratory in Virginia, has been researching how sunscreen pollution might impact coral populations.

In 2019, Downs and a research team took samples from the ground and water around beach showers on three Hawaiian islands.

They found high levels of oxybenzone, avobenzone, benzophenone-2, octocrylene, and octinoxate, which are all chemicals found in sunscreen.

“The people who lived there have always wondered if it was an issue,” Downs told Undark.
Why is this so concerning?

Downs has investigated how human-caused pollution, such as sunscreen and microplastics, can damage coral reefs.

What is most concerning is so-called “zombie” corals, or otherwise healthy-looking corals made up of adults that aren’t reproducing.

Scientists first discovered this phenomenon in 2016 around the Caribbean, and it adds a new level of concern for a species that is already struggling amid global heating, coastal development, and other forms of marine pollution.

Corals are important for many reasons, as reefs provide healthy ecosystems for a huge amount of living species. The United Nations Environment Programme says that while coral reefs occupy just 1% of the ocean floor, they provide a habitat for 25% of marine life.

They act as natural flood defenses in coastal areas, and they are also a source of food and medicine. The National Oceanic and Atmospheric Administration says that half a billion people depend on coral reefs.
What can be done to protect coral reefs?

While individually it might seem like trying to stop harmful sunscreen chemicals from entering oceans will make little difference, Downs is convinced even small changes can be beneficial in terms of reducing concentrations.

“One swimmer, one shower, does it pose a threat? But 500 swimmers and more than 500 showers?” he observed.

Although sunscreen is important to ensure skin health and reduce the risk of cancer, staying out of the water when wearing it or waiting until you get home to have a shower can prevent these pollutants from making it to the ocean.

Otherwise, the United Nations Environment Programme says that urgently tackling rising global temperatures, limiting coastal development, and reducing stressors such as overfishing and sewage pollution are all ways to protect coral reefs.

When it comes to the former, cutting reliance on dirty fuel is essential to slow global heating, which warms oceans and leads to coral bleaching. That means reducing plastic consumption, traveling by foot, bike, public transport, or electric cars, and making the most of renewable energy sources.

Elsewhere, fishing pollution is also a concern for coral health, with nets, lures, and hooks among the items often found wrapped around fragile corals.