(Reuters) — The geology of the Brazilian volcanic island of Trindade has fascinated scientists for years, but the discovery of rocks made of plastic debris in this remote turtle haven is raising alarm.
The melted plastic has mixed with rocks on the island, located 1,140 kilometers from the southeastern state of Espirito Santo, which the researchers say is evidence of the growing influence of humans on Earth’s geological cycles.
“This is new and terrifying at the same time, because the contamination has reached geology,” said Fernanda Avelar Santos, a geologist at the Federal University of Paraná.
Santos and his team carried out chemical tests to find out what kind of plastics are in the rocks, called “plastigglomerates” because they are made up of a mixture of sedimentary granules and other debris held together by plastic.
“We have identified that (the contamination) comes mainly from fishing nets, which are very common debris on the beaches of Trinidade Island,” Santos said. “The nets are dragged by the ocean currents and accumulate on the beach. When the temperature rises, this plastic melts and becomes embedded with the natural material on the beach.”
The island of Trindade is one of the most important places in the world for the conservation of the green turtle, Chelonia mydas, to which thousands of specimens arrive each year to spawn. The only human inhabitants of 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 (plastic) samples is a permanently preserved area in Brazil, close to where green turtles spawn,” explains Santos.
The discovery raises questions about the legacy of humans on Earth, Santos says.
“We talk a lot about the Anthropocene, and this is the moment,” Santos said, referring to a geological epoch defined by human impact on the planet’s geology and ecosystems.
“Pollution, litter in the sea, and plastic improperly dumped in the oceans is becoming geological material… preserved in Earth’s geological records.”