The mass of plastics in the Atlantic Ocean is approximately 21 million tonnes, according to research conducted by the National Oceanography Centre.
This figure is only for three of the most common types of plastic litter in a limited size range. The lead author of the research paper, published in the journal Nature Communications, Dr Katsiaryna Pabortsava from the National Oceanography Centre (NOC), 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.”
In collaboration with co-author Professor Richard Lampitt, of the NOC, Pabortsava collected seawater samples during the 26th Atlantic Meridional Transect expedition, which took place between September and November 2016. The team filtered large volumes of seawater at three selected depths in the top 200 metres and detected and identified plastic contaminants using a state-of-the-art spectroscopic imaging technique. Their study focussed on polyethylene, polypropylene, and polystyrene, which are the commercially most prominent and most littered types of plastic.
Lampitt, said: “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.
“In order to determine the dangers of plastic in the Atlantic Ocean 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.”