Full scale of plastic pollution in the world’s oceans revealed for first time – More than five trillion pieces weighing 269,000 tons are floating in our oceansPosted by Jim at Wednesday, December 10, 2014
By Oliver Milman
10 December 2014
(The Guardian) – More than five trillion pieces of plastic, collectively weighing nearly 269,000 tonnes, are floating in the world’s oceans, causing damage throughout the food chain, new research has found.
Data collected by scientists from the US, France, Chile, Australia and New Zealand suggests a minimum of 5.25tn plastic particles in the oceans, most of them “micro plastics” measuring less than 5mm.
The volume of plastic pieces, largely deriving from products such as food and drink packaging and clothing, was calculated from data taken from 24 expeditions over a six-year period to 2013. The research, published in the journal PLOS One, is the first study to look at plastics of all sizes in the world’s oceans.
Large pieces of plastic can strangle animals such as seals, while smaller pieces are ingested by fish and then fed up the food chain, all the way to humans.
This is problematic due to the chemicals contained within plastics, as well as the pollutants that plastic attract once they are in the marine environment.
“We saw turtles that ate plastic bags and fish that ingested fishing lines,” said Julia Reisser, a researcher based at the University of Western Australia. “But there are also chemical impacts. When plastic gets into the water it acts like a magnet for oily pollutants.
“Bigger fish eat the little fish and then they end up on our plates. It’s hard to tell how much pollution is being ingested but certainly plastics are providing some of it.”
The researchers collected small plastic fragments in nets, while larger pieces were observed from boats. The northern and southern sections of the Pacific and Atlantic oceans were surveyed, as well as the Indian ocean, the coast of Australia and the Bay of Bengal.
The vast amount of plastic, weighing 268,940 tonnes, includes everything from plastic bags to fishing gear debris.
While spread out around the globe, much of this rubbish accumulates in five large ocean gyres, which are circular currents that churn up plastics in a set area. Each of the major oceans have plastic-filled gyres, including the well-known ‘great Pacific garbage patch’ that covers an area roughly equivalent to Texas.
Reisser said traversing the large rubbish-strewn gyres in a boat was like sailing through “plastic soup.”
“You put a net through it for half an hour and there’s more plastic than marine life there,” she said. “It’s hard to visualise the sheer amount, but the weight of it is more than the entire biomass of humans. It’s quite an alarming problem that’s likely to get worse.” [more]
ABSTRACT: Plastic pollution is ubiquitous throughout the marine environment, yet estimates of the global abundance and weight of floating plastics have lacked data, particularly from the Southern Hemisphere and remote regions. Here we report an estimate of the total number of plastic particles and their weight floating in the world's oceans from 24 expeditions (2007–2013) across all five sub-tropical gyres, costal Australia, Bay of Bengal and the Mediterranean Sea conducting surface net tows (N = 680) and visual survey transects of large plastic debris (N = 891). Using an oceanographic model of floating debris dispersal calibrated by our data, and correcting for wind-driven vertical mixing, we estimate a minimum of 5.25 trillion particles weighing 268,940 tons. When comparing between four size classes, two microplastic <4.75 mm and meso- and macroplastic >4.75 mm, a tremendous loss of microplastics is observed from the sea surface compared to expected rates of fragmentation, suggesting there are mechanisms at play that remove <4.75 mm plastic particles from the ocean surface.