The researchers say the density of trash was the highest recorded anywhere in the world, despite Henderson Island’s extreme remoteness. The island is located about halfway between New Zealand and Chile and is recognized as a UNESCO world heritage site.

Jennifer Lavers, a research scientist at Australia’s University of Tasmania, was lead author of the report, which was published Tuesday in “Proceedings of the National Academy of Sciences.”

Lavers said Henderson Island is at the edge of a vortex of ocean currents known as the South Pacific gyre, which tends to capture and hold floating trash.

“The quantity of plastic there is truly alarming,” Lavers told The Associated Press. “It’s both beautiful and terrifying.”