Remote islands overwhelmed by plastic waste

Plastic waste left on beaches represents a new threat to the turtle population. Researcher Jennifer Lavers spent weeks sifting through rubbish from the beaches of two remote islands - and what she found could have alarming consequences for the lives of these animals.

In 2017, many were shocked to learn that the beaches of the uninhabited Henderson Island in the South Pacific Ocean had turned into a plastic waste dump. Shortly thereafter, scientists discovered about 414 million pieces of plastic washed ashore on the beaches of the Cocos Islands, off the coast of Western Australia. Research has revealed that the accumulation of plastic parts is significantly raising the temperatures of the sand on these beaches.

Plastic as an insulator

“Plastic creates almost an insulation, a barrier, that affects the passage of UV light, wind, and moisture,” explains Dr. Jennifer Lavers of the University of Tasmania. “The plastic significantly increases the temperature of the sand on the beach, by up to 4.4°F. This has major consequences for the animal species that live, feed, and reproduce in the sand“.

Impact on wildlife

The habitat provided by the islands is vital for a large number of animal species that live in the sandy dunes, such as crabs and sea turtles. Young turtles, in particular, are greatly affected by plastic waste because their sex is determined by the temperature of the sand in which the eggs are incubated: higher temperatures result in more female turtles.

“An increase in sand temperature leads to a rise in the number of female turtles and a decrease in the number of males. This obviously has serious consequences for their reproductive activity, especially considering that turtles are an endangered species,” Dr. Lavers notes.

Threats to the food chain

But it’s not just turtles that are threatened by the presence of plastic on the beaches. Other small invertebrates, known as meiofauna, live in the sand and serve as food for certain birds called plovers. These birds typically stop on oceanic beaches during migration periods. The disappearance of meiofauna breaks an important link in the marine ecosystem’s food chain, posing a problem for birds and fish that inhabit the islands.

The role of remote beaches

These are virtually uninhabited islands where plastic accumulates, carried by ocean currents,” explains the researcher. “These pristine beaches act like a sieve, or a giant trash can, collecting all the plastic floating in the ocean currents. Being remote and uninhabited, if there were no one to clean and take care of them, the plastic would continue to accumulate undisturbed.

Source: University of Tasmania