They’re Everywhere: Sea Turtles Now Nest Among Plastic Rocks

A study of sea turtle nesting sites on an isolated volcanic island off Brazil has revealed alarming concentrations of “plastic rocks,” underscoring once again the scale of this type of pollution.

Plastiglomerates

In 2019, scientists had uncovered a cluster of unusual bluish rocks on Trindade Island, located about 1,140 kilometers off the coast of Espírito Santo state in southeastern Brazil. Chemical analyses later revealed that they consisted of rocky sediments and melted plastic.

As part of new work published in the Marine Pollution Bulletin, the same team returned to Trindade Island and identified these “plastiglomerates” on six beaches, including Tartarugas (“turtle beach” in Portuguese), where significant populations of green turtles (Chelonia mydas) nest.

“The question of whether we have entered the Anthropocene [the geological era characterized by the major impact of human activities on the planet] rests precisely on the presence of artificial materials buried in sediments,” explains the team. “On Trindade, they were found as deep as 10 centimeters below the surface of the nests.”

The examination of the collected samples confirmed the presence of high-density polyethylene (used in ropes) as well as copper, clearly indicating that this pollution source originated from fishing and maritime transport. According to the team, the distinct shapes of the plastic rocks, smooth and rounded at the water’s edge and becoming more irregular as one moves away from the shore, show that this material has now become an integral part of the beach’s “geological cycle.”

Global Threat

Today, no ecosystem escapes this form of pollution, found from the depths of the Mediterranean Sea to the summit of Mount Everest and all the way to Antarctica.

In recent years, an increasing number of studies have also revealed the presence of tiny plastic particles in several of our organs. Although their impact on human health remains poorly understood, research suggests they could disrupt the endocrine system in particular.