Amount of plastic in Atlantic Ocean 'massively' underestimated, say scientists

There is "massively" more plastic in the Atlantic Ocean than previously thought, a new study has claimed.

The research, by the UK's National Oceanography Centre (NOC), claims that there may be 12 to 21 million tonnes of three of the most common types of microplastic floating in a relatively small section of the ocean.

This means that there could be around 200 million tonnes of just these common plastics in the sea as a whole, researchers said - posing an even greater threat to the ecosystem than thought.

Previous estimates suggested between 17 million and 47 million tonnes had been released into the ocean between 1950 and 2015.

Plastic debris on Almaciga Beach, on the north coast of the Canary Island of Tenerife (AFP/Getty Images)

The study's lead author, Katsiaryna Pabortsava, said: “Previously, we couldn’t balance the mass of floating plastic we observed with the mass we thought had entered the ocean since 1950.

“This is because earlier studies hadn’t been measuring the concentrations of ‘invisible’ microplastic particles beneath the ocean surface.

“Our research is the first to have done this across the entire Atlantic, from the UK to the Falklands.”

Co-author Professor Richard Lampitt added: “If we assume that the concentration of microplastics we measured at around 200 metres deep is representative of that in the water mass to the seafloor below with an average depth of about 3,000 metres, then the Atlantic Ocean might hold about 200 million tonnes of plastic litter in this limited polymer type and size category.

“This is much more than is thought to have been supplied.”

Plastic washed up on the Thames in 2018 (Getty Images)

The researchers collected seawater samples in the Atlantic Ocean from September to November 2016.

They filtered large volumes of seawater at three selected depths in the top 200 metres from the surface. The scientists detected and identified plastic particles using state-of-the-art spectroscopic imaging techniques.

Prof Lampitt said: “In order to determine the dangers of plastic contamination to the environment and to humans we need good estimates of the amount and characteristics of this material, how it enters the ocean, how it degrades and then how toxic it is at these concentrations.

“This paper demonstrates that scientists have had a totally inadequate understanding of even the simplest of these factors, how much is there, and it would seem our estimates of how much is dumped into the ocean has been massively underestimated.”