Plastic rocks are threatening wildlife on Brazil’s easternmost island — I’m studying how
Geologist Fernanda Avelar Santos finds that fishing gear and packaging are creating a new type of pollution
I made my fourth visit to Trindade Island in the South Atlantic Ocean — Brazil’s easternmost point — in October 2022. The island is one of the most important conservation spots in the world for marine life, including green sea turtles (Chelonia mydas), birds and coral reefs, and it’s home to volcanic rock outcrops. But the ocean currents bring litter, such as fishing gear and plastic packaging.
During an April 2019 expedition, I found a 12-square-metre area of beach where plastic has been incorporated into natural rocks. My team and I identified three types of plastic rock, one of which we had discovered for the first time. We called them plastistones, because they are melted chunks of plastic that are analogous to igneous rock. We hypothesize that they form when plastic debris that has washed up on shore is heated by camp fires. The other two plastic rock types had already been described in 2014 and 2019, from Hawaii and the United Kingdom, respectively.
I have brought about 130 of the plastic rocks back to our laboratory at the Federal University of Paraná in Curitiba. I feel curiosity and sadness when I study them. In this image, I’m analysing them under a microscope to learn about their structure and their mineral and chemical make-up. Most of the plastic incorporated into rocks comes from melted fishing nets.
I’m very interested in how these new kinds of rock will break down to become a persistent type of pollution. Troublingly, this is occurring in the region with the highest concentration of green-turtle nests in Brazil, so it could become a long-term threat to their survival.
Our research offers definitive proof that we are living in the Anthropocene epoch, in which Earth processes are dominated by human-caused phenomena such as pollution, carbon emissions and ocean acidification. Human pollution is now part of the Earth’s geological cycles.
Nature 620, 238 (2023)
doi: https://doi.org/10.1038/d41586-023-02448-1
This story originally appeared on: Nature - Author:Virginia Gewin
