Plastic pollution is everywhere, from the deep depths of the ocean to the highest peak in the mountain; from the guts of sea birds to the guts of coral. Now, a study in the October 2019 issue of the journal Science of the Total Environment reveals that a new type of marine plastic pollution could soon paint the world’s beaches flaky plastic blue.
The authors of the study call this type of pollution “plasticrust.” Which is essentially flecks of crusty, blue and white plastic that hardened onto the rocky surfaces where the land and sea meet.
Recently while surveying the beaches of Madeira – an island in the Atlantic Ocean southwest of Portugal, researchers found chunks of plasticrust coated around 10% of the rocks. Unfortunately, this was a significant increase in plasticrust compared to a previous research trip on the island just three years ago. A chemical analysis revealed that the crust was made out of polyethylene – a common plastic often used in single-use containers and plastic bags.
Lead study author Ignacio Gestoso, a marine ecologist at the Marine and Environmental Research Center (MARE) on Madeira said :
The crust likely resulted from large pieces of plastic crashing against the shore over time, gradually accumulating on the rocks like algae.
But, also like algae, the crust could possibly already be making its way into the marine food chain. Some sea snails such as Tectarius striatus feed on algae from ocean side rocks. Now, Gestoso and his team found the snails crawling over nearly as many plasticrust-coated surfaces as non-polluted ones.
It’s not clear whether the snails were eating the plasticrust or just grazing on it. Nonetheless, prior studies have revealed similar species of snail unable to distinguish clean algae from microplastic-covered algae so the possibility does exist.
While the crust has so far been observed on only one island, it is sadly, not the first time that plastic has appeared on beaches in a new form. In 2014, researchers in Hawaii noticed that plastic trash, melted by campfires, had combined with tiny beach rocks and lava fragments to form a new type of rock that they called a “plastiglomerate.” These trash rocks are most likely present on beaches all around the world.
All of these new types of plastic are engraving today’s era of plastic pollution into Earth’s geologic record. So keep this in mind, the next time you say yes to a plastic bag.
