A New Material That's Part Plastic and Part Rock Is Forming on This Portuguese Island

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Plasticrust as seen on rocks in Madeira
Researchers believe waves carrying plastic steadily fused waste to rock. Ignacio Gestoso
Plasticrust as seen on rocks in Madeira
first found signs of plastic-infused rocks during a 2016 visit to Madeira. Ignacio Gestoso

You know we have a problem when our plastic pollution starts becoming a permanent fixture of the planet's geology.

And that seems to be exactly what's happening on the Portugeuese island of Madeira — a place famed for wine, mountain peaks and, perhaps soon, its plastic-encrusted shoreline.

Back in 2016, marine biologist Ignacio Gestoso first spotted the unusual patterns on rocks scattered along the island's shore, as Gizmodo reports. It seemed that plastic was no longer content to wash ashore in its manufactured state, as bottles and wrappers and caps. Instead, it had formed a kind of hybrid material with the rock that would become known as "plasticrust."

At the time, Gestoso wrote off the strange new material as an unhappy coincidence. Surely, this union of plastic and rocks couldn't last.

But when he and his team returned to the island a year later, they found the marriage had not only lasted, but thrived.

In a new study, published in Science of The Total Environment, Gestoso and his colleagues describe "plasticrust" as a synthetic moss covering huge swathes of the island's stony shoreline — and even sporting bright, new and terrible colors.

In fact, the researchers estimate plasticrust taints nearly 10 percent of rocky surfaces on the Madeira shoreline. At this rate, plasticrust is poised to become a part of our geological record.

"The dimension of the problem is so large that it is possible our current era will generate an anthropogenic marker horizon of plastic in earth's sedimentary record," the authors note in the study abstract.

Plasticrust as seen on various rocks.
The research team determined the colorful veneer on these rocks to be polyethylene. Ignacio Gestoso

What fresh plastic hell is this? We've certainly seen plastic waste take on some bizarre new forms. On Hawaiian beaches, for example, a garish gunk known as "plastiglomerate" was observed back in 2014. But that was the result of campfires literally cooking plastic waste into the rocks.

Plasticrust, on the other hand, may just go with the flow — making it much more likely to spread.

Plasticrust as seen on rocks in Madeira
Researchers believe waves carrying plastic steadily fused waste to rock. Ignacio Gestoso

Speaking to Gizmodo, Gestoso suggests plastic debris rode Madeira's renowned waves and smashed into its equally renowned rocks. That forceful splatter, along with subsequent tidal bashes, coated the shores in a layer of polyethylene.

Yes, that's the same stuff we use to make single-use packages, bottles and other throwaway containers. While governments are increasingly limiting or banning it altogether, Madeira seems to have become a catch-all for our single-use sins.

It may also be a slippery slope for marine life, like the sea snails and barnacles that set up shop between tides on all-natural rock crusts. Gestoso is understandably unsure about the nutritional value of Teflon-coated surfaces, nor how plasticrust might affect might affect the entire food chain. Mollusks, he noted, treated the tainted rocks the same way they did their natural counterparts.

"Consequently, its inclusion as a potential new marine debris category in management and monitoring actions should be pondered," the study authors note.

For now, Gestoso's findings add yet another dimension to a plastic plague that has tainted everything from the remotest mountains to the shores of this once-pristine Portuguese paradise.

"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 told Gizmodo. "Unfortunately, the magnitude of the problem is so huge that few places are free of plastic pollution."