A recent discovery of plastic debris-covered rocks on the remote Brazilian island of Tridade, which is home to a variety of rare marine species, has alarmed scientists. The presence of plastic on the secluded volcanic island known for its unique geology was “terrifying,” according to Fernanda Avelar Santos, a geologist at the Federal University of Parana.
Geological features of Trindade Island
Trindade Island is the most eastern and remote point in Brazilian territory, located approximately 1,140 kilometres from the southeastern state of Espirito Santo. Trindade first appeared three million years ago as a result of volcanic activity beneath the Atlantic Ocean. Many species of native flora and fauna, including seabirds and marine creatures, can be found on Trindade and the nearby Martim Vaz archipelago.
Trindade is well-known for being one of the most important conservation and nesting sites for green sea turtles (Chelonia mydas), both in Brazil and globally, with nearly 1,800 nests annually on a small stretch of land. It is also known for harbouring native seabirds such as the Trindade Petrel and the great frigatebird, both of which are found only in the Indo-Pacific and not the Atlantic. Sharks, dolphins, and corals can also be found in the surrounding area.
Its terrain is unique due to its formation due to volcanic activity, reaching 600 m elevation at multiple points while having surrounding oceanic depths of 6000 m. The island is thought to be one of Brazil’s most recent manifestations of alkaline volcanic activity. It is located at the eastern end of a chain of guyots, or submarine volcanic mountains with flat tops, that stretches east to west about 1,100 kilometres from the continental shelf off the coast of Brazil.
The island was discovered by a Portuguese sailor in 1502, but it was not inhabited by humans until 1730, when Azorean communities colonised the island. They failed in their attempt and left Trindade in the years that followed, abandoning their domestic animals such as goats and pigs, which scientists blame for destroying much of the island’s original vegetation.
Currently, Trindade is a protected area with no humans present except for a small Brazilian Navy crew that patrols the waters. It’s also devoid of tourist activity.
How did plastic rocks get formed on the remote Island?
Ms. Santos of Parana University and her colleagues, who discovered the rocks made of plastic debris, claim that melted plastic became intertwined with rocks on the island. Plastic reaching Trindade despite being hundreds of miles from the mainland, according to the geologists, was evidence of humans’ growing influence over the earth’s geological cycles.
According to Ms. Santos, the team ran chemical tests on the rocks to determine what kind of plastics were in these rocks, which are known as “plastiglomerates” because they are made of sedimentary granules and other debris held together by plastic.
“We determined that (the pollution) is primarily caused by fishing nets, which are a common type of debris on Trindade Island’s beaches,” the geologist explained. “The (nets) are dragged by the marine currents and accumulate on the beach. When the temperature rises, the plastic melts and becomes embedded in the natural material of the beach.”
The scientists also revealed that the spot where they found the plastic rocks is a “permanently preserved area in Brazil, near the place green turtles lay their eggs”.
Affects of Marine Pollution
The geologist stated that the ecologically damaging discovery was a clear manifestation of the Anthropocene, a term proposed by scientists to describe the current geological epoch in which humans are knowingly shaping the planet, rather than the usual geological processes that take millions of years.
“The Anthropocene: the Age of Humans,” according to the UN Human Development Report 2020. For the first time in history, the most serious and immediate, even existential, threats are man-made and unfolding on a global scale.”
Referring to the rocks made of plastic, Ms. Santos said that garbage and plastic dumped incorrectly in the oceans are turning into “geological material” and getting preserved in the “earth’s geological records”.
According to the UN, decades of overuse and an increase in single-use, short-lived plastics have resulted in devastating levels of marine pollution. Every year, nearly 12 million tonnes of plastic are swept into the oceans, and gyres, also known as “plastic islands,” have formed.
While the majority of plastics remain intact for years, if not centuries, some erode to form’microplastics,’ which are then consumed by marine wildlife and, eventually, humans. Microplastics are plastic particles with a diameter of less than 5mm. They account for more than 80% of all ocean debris.
Microplastics have been discovered in a variety of environments, including remote Swiss mountains and fresh Antarctic snow, as well as human blood.
About Trindade Island
Trindade Island is the most eastern and remote point in Brazilian territory, located approximately 1,140 kilometres from the southeastern state of Espirito Santo.
The island was discovered by a Portuguese sailor in 1502, but it was not inhabited by humans until 1730, when Azorean communities colonised the island.
According to the UN, decades of overuse and an increase in single-use, short-lived plastics have resulted in devastating levels of marine pollution.