Extract from ABC News
Research scientist Jennifer Lavers has spent weeks sifting through the world's waste on two remote sets of islands — and what she has found could have alarming consequences for wildlife.
Key points:
- New research has found plastic debris is increasing the temperature extremes of sand
- Sand temperature affects the gender of turtle hatchlings
- About 414 million pieces of plastic have been found on Australia's Cocos Keeling Islands
In 2017, many were shocked to learn the shores of uninhabited Henderson Island in the South Pacific Ocean were littered with plastic waste.
Not long after, scientists found about 414 million pieces of plastic washed up on the beaches of the Cocos Keeling Islands, off Australia's west coast.
Now, research is finding the accumulation of plastic debris is significantly increasing the temperature extremes of the sand.
"It
creates almost like an insulation or a boundary layer that affects how
much UV light, wind and moisture might get past it," Dr Lavers said.
Dr Lavers from the University of Tasmania's Institute for Marine and Antarctic Studies said the findings, which were published in scientific journal Elsevier this month, were very concerning for the species that lived, bred and fed on the sand.
"Whether it will lead to an extinction, we've yet to demonstrate that … but likely what it will do in the interim is force species to move, shift and adjust," she said.
"Can they change at a rapid enough pace? All I can really say is stay tuned."
From turtle gender to shorebird food
Dr Lavers said the islands were incredibly important for a diverse array of animals that nested in the dunes, including crab species and sea turtles.
Turtle hatchlings in particular are expected to be affected by the plastic waste because their gender is determined by the temperature of the sand where their eggs are incubated.
"So a higher temperature means more females," Dr Lavers said.
"[A sand temperature increase is] going to contribute to an increase in female turtle offspring and fewer male turtle offspring and that is obviously problematic considering that turtles are an endangered species."
Dr Lavers said the sand was also home to tiny invertebrates called meiofauna, which provided food for shorebirds that stopped over at the islands as they migrated.
"The sandy sediments under their feet have all of this meiofauna living in it — all these little worms and teeny little crabs and oysters and shells and things that they can eat and live on," she said.
Dr Lavers said if the meiofauna declined, there would not be enough food for the shorebirds that had relied on those islands for hundreds of generations.
So what will happen?
The two sets of islands are largely uninhabited, making them ideal locations for researchers because there has been no interference with the plastics.
Dr Lavers said the islands acted like a sieve in the oceans.
"If it is an uninhabited remote beach where clean-ups don't take place, then that plastic basically accumulates there uninterrupted."
Dr Lavers said previous studies had investigated what would happen to animals in coastal environments as the temperature increased in relation to climate change.
She said the effects of beaches warming because of plastic debris were likely to be similar.
"What these other studies have found is that for a huge swathe of species — about 40 per cent — are likely to experience things like local extinctions when maximum temperatures increase more than about half a per cent," she said.
Dr Lavers said scientists had already found a number of species had shifted more than 30 kilometres per decade in response to sand temperatures warming by around 0.2C in that time.
"The amazing thing is that these changes that have been documented now for many years are in response to warming that is much, much less than what we recorded for plastics [research]," she said.
"It's quite unlikely that many, if any, marine species could adjust to such a substantial change over such a short period," Dr Lavers said.
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