Rocks Are Getting A Dangerous Plastic Crust, Due To Our Plastic Waste In The Ocean

We've been polluting our oceans with plastic for decades, so it should come as no surprise that a lot of it has accumulated.

It's not just staying there anymore though, finding its way to the deepest parts of the ocean. Now it's even coming back to land in a new way.

Images courtesy: Ignacio Gestoso

Researchers at the the MARE-Marine and Environmental Research Center on the Portugese island of Madeira have noticed a new type of rock formation forming on the shore. 'Plasticrust', as it's being called, appears to be a thin coating of plastic that's growing on the wave-thrashed rocks like barnacles.

Ignacio Gestoso, a marine ecologist at the institute first noticed the strange formation back in 2016. The light blue veneer looked like someone has smeared used chewing gum on the rocks. At the time, he and his team took some photos and samples for study, assuming it was a singular occurrence.

A year later, the plasticrust was still there. Worse, this year, it seemed to have spread to a larger area.

The plastic coating has, in three years, gone from a single sighting to covering 10 percent of the rocks in the area. It's also now appearing in all kinds of colours. Analysis of the crust indicated that it's composed of polyethylene, which is the most commonly used plastic, often found in food and product packaging.

"It likely originated by the crash of large pieces of plastic against the rocky shore, resulting in plastic crusting the rock in a similar way algae or lichens do," Gestoso told Earther.

It's just another indication of just how much plastic pollution affects our planet. When it enters the ocean, plastic doesn't decompose. Instead, it breaks up into microscopic particles called microplastics, that enter the marine food chain and even end up reaching humans in the water we drink and food we eat.

This isn't even the first time we've found a new material in the environment borne of our plastic pollution. Six years ago, researchers found a plastic-rock mix on a beach in Hawaii, after campfires melted nearby plastic waste and bonded it with the sand and pebbles around. The only difference is, plasticrust didn't even fire to melt down the plastic and fuse it with something else. There's just so much of it in the oceans that it's simply getting deposited on the rocks by waves and sticking around.

There might be more serious risks to this than we consider however. On the island of Madeira, the plasticrust is slowly replacing natural rock surfaces, which molluscs and similar creatures stick to in order to feed from the algae coating them.

The research team found here that the local sea snails were sticking to this plasticrust as much as regular rock face, meaning they're probably feasting on the algae forming on this plastic coating. Therefore, these snails might also be ingesting some of that plastic as well, further polluting the food chain.

"As a marine ecologist researcher, I would prefer to be reporting other types of findings, and not a paper describing this sad new way of plastic pollution," Gestoso said. "Unfortunately, the magnitude of the problem is so huge that few places are free of plastic pollution."