Culture

How Much Plastic is in the Ocean?

The Orkney News has reported several times about the presence of plastics, including micro plastics in our seas. A new study of the upper Atlantic suggests that there are 10 times more plastics than was previously thought.

A graphic showing the new estimated mass of microplastic in the Atlantic against the previous estimate Credit: The National Oceanography Centre

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.”

Dr Katsiaryna Pabortsava in the microplastics lab at the National Oceanography Centre credit: The National Oceanography Centre

Seawater samples were collected during the 26th Atlantic Meridional Transect expedition in September to November 2016.

Large volumes of seawater were filtered at three selected depths in the top 200 metres. The scientists detected and identified plastic contaminants using state-of-the-art spectroscopic imaging technique.

Their study focussed on polyethylene, polypropylene and polystyrene, which are commercially most prominent and also most littered plastic types.

Professor Richard Lampitt, also from the NOC, 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 3000 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 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.

“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”.

The research was published in the journal Nature Communications.

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