The geology of Brazil’s volcanic Trindade Island has fascinated scientists for years, but the discovery of rocks made from plastic waste in this remote turtle sanctuary is causing alarm.
Molten plastic has intertwined with rocks on the island, which is 1,140 km (708 miles) from the southeastern state of Espirito Santo, which researchers say is evidence of the growing human influence on the Earth’s geological cycles.
“This is both new and terrifying because the pollution has reached the geology,” said Fernanda Avelar Santos, a geologist at the Federal University of Parana.
Santos and her team performed chemical tests to find out what kind of plastics are in the rocks, called “plastiglomerates” because they’re made of a mixture of grains of sediment and other debris held together by plastic.
“We identified ourselves [the pollution] comes mainly from fishing nets, which is very common on Trinidade Island beaches,” said Santos. “The [nets] are carried away by the sea currents and accumulate on the beach. As the temperature rises, this plastic melts and becomes embedded with the natural material of the beach.” Trindade Island is one of the world’s most important sanctuaries for green sea turtles, or Chelonia mydas, with thousands coming here every year to lay their eggs. The only human residents on Trindade are members of the Brazilian Navy, which maintains a base on the island and protects the nesting turtles.
“The place where we found these samples [of plastic] is a permanently conserved area in Brazil, near where green turtles lay their eggs,” said Santos.
The discovery raises questions about the heritage of humans on Earth, Santos says.
“We talk so much about the Anthropocene, and this is it,” Santos said, referring to a proposed geological epoch defined by human impact on the planet’s geology and ecosystems.
“The pollution, the garbage in the sea, and the plastic that is improperly dumped into the oceans are becoming geological material… preserved in the Earth’s geological record.”