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The rising tide of microplastics on the ocean floor: The amount of plastic debris has tripled in 20 years at depths of more than 100 meters, researchers say
- Accumulation of microplastics mimics the increasing amount of plastic products used by society, scientists said
- It shows that the world is still a long way from reducing single-use plastic, they warned
- A team analyzed five sediment cores that were extracted in the Balearic Sea
The amount of microplastics found at the bottom of the oceans has tripled in 20 years, the researchers found.
Tiny fragments of plastic, smaller than the human eye can see, have been accumulating on the seabed at a depth of more than 100 meters, the study reveals.
Their accumulation mimics the increasing amount of plastic products used by society for things like containers, bottles and clothing, the scientists said.
And it shows that the world is still a long way from achieving a reduction in single-use plastic, they warned.
Tiny fragments of plastic, smaller than the human eye can see, have accumulated on the seabed at a depth of more than 100 meters, the study reveals.
The team analyzed five sediment cores that were mined in the Balearic Sea, which lies east of Spain and south of France, in November 2019.
Each core was 37 cm long and allowed the researchers to see how many microplastics were on the seabed from 1965, when plastics began to be mass-produced, onwards.
Their results, published in the journal Environmental Science and Technology, revealed that since the turn of the millennium, the amount of decomposed plastic particles on the seabed has tripled.
The team of researchers includes those from the Universitat Autònoma de Barcelona (ICTA-UAB) in Spain and the Department of Built Environment at Aalborg University (AAU-BUILD) in Denmark.
They said the amount of microplastics found embedded in the seabed mimics global plastic production from 1965 to 2016.
Researcher Laura Simon-Sánchez said: “Specifically, the results show that, since the year 2000, the amount of plastic particles deposited on the seabed has tripled and that, far from decreasing, the accumulation has not stopped growing , blending in with the global production and use of these materials.’
Worryingly, the tiny pieces of plastic remained undisturbed since they were first deposited decades ago.
The team analyzed five sediment cores that were mined in the Balearic Sea, which lies east of Spain and south of France, in November 2019.
Once trapped on the seafloor, they no longer degrade, whether due to a lack of erosion, oxygen, or light.
“Once deposited, degradation is minimal, so plastics from the 1960s remain on the seabed, leaving traces of human pollution there,” the scientists said.
Michael Grelaud, who was also part of the research team, added: “This has allowed us to see how, since the 1980s, but especially in the last two decades, the accumulation of polyethylene and polypropylene particles from packaging, bottles and film for food has increased, as well as polyester from synthetic fibers in garment fabrics.’
They found that polypropylene, used primarily for packaging, was the most abundant.
Combined, the three different types of particles reached a maximum weight of 1.5 milligrams per kg, which was found at the top of the sediment core, representing the most recent years.
The environmental impacts of microplastics are not yet fully understood, although it has been well established that small pieces of plastic have been able to contaminate food and water.
Previous research has estimated that up to 14 million tons of microplastics lie on the seafloor, with plastic pollution reaching sea ice around Antarctica and even the world’s deepest waters of the Mariana Trench.