When the crew of the Greenpeace ship Esperanza pulled in its one-metre net from the surface of the Atlantic about 300km south-east of the Azores last year, it was surprised only by the quantity of what it found.
Washing around in the net were nearly 700 minuscule and unidentifiable fragments of plastic; 57 pieces of synthetic fishing line and leftover strands from dumped nets and rope; a handful of flakes from old plastic bags, including one with a zip-type seal still attached; and a dozen so-called nurdles — white pellets, looking like grains of rice, which are the raw material of the packaging industry. All this microplastic had been collected in just four nautical miles (7,4km).
“When we conducted the first trawl and brought the sample back on board, I was shocked, and so was the crew,” says Adam Walters, a researcher at Greenpeace’s laboratory in Exeter, south-west England. “We had been sailing then for more than a month, looking at the ocean every day, and had no idea that all this plastic was floating by the ship.”
It was not just the Atlantic Ocean. Wherever the Esperanza went last year as part of Greenpeace’s Defend Our Oceans campaign, it trailed its sample net from a boom beside the ship. It was more or less the same story everywhere.
After the contents of the trawl had been tipped into a washing tank, and once the sea creatures and the larger pieces of floating debris had been removed, there was always the same mosaic of pieces of microplastic floating on the surface.
Walters says: “We knew there were big pieces everywhere, so we would expect to find small pieces, but it was a shock. It is shocking when something you thought was pristine turns out to be polluted in that way.
In the north Pacific, where a gigantic sea of rubbish — dubbed the great garbage patch, and which may contain 100-million tonnes of flotsam — swirls around in a system of currents known as the North Pacific Gyre, a large amount of microplastic was expected; indeed, the highest concentrations were found there. But the Esperanza also discovered an unexpectedly high number of particles in the Atlantic, around the Canary Islands and the Azores.
The haul of microplastic continued in the Mediterranean, the Red Sea, the Indian Ocean, in the Bay of Bengal and off Malaysia and the Philippines. Only in the furthest reaches of the south Pacific did the count go down.
Plastic makes up 60% to 80% of marine litter and at least 267 species, including 44% of seabirds and 43% of marine mammals, are known to have suffered because of entanglement or ingestion.
According to the United Nations Environment Programme there are about 13 000 pieces of plastic litter in every square kilometre of the ocean’s surface. — Â