Researchers from Chile, France, Australia, the U.S. and New Zealand teamed up to gather information during a six-year period ending in 2013. The 24 expeditions uncovered about 269,000 tonnes of plastic waste.
The study, published in the journal PLOS ONE, is the first of its type to examine plastics of all sizes in the oceans. It found that most of the particles were “micro plastics” measuring less than five millimetres.
It cautioned that its estimates are “highly conservative” and didn’t account for the massive amounts of plastic “present on shorelines, on the seabed, suspended in water columns and within organisms.”
The study says the presence of plastics is a problem for marine life, such as seabirds and marine reptiles who end up either ingesting or becoming entangled in the plastic.
The foreign matter is then transferred into the tissues and organs of the animals, which ends up in the food chain.
“Bigger fish eat the little fish and then they end up on our plates,” Julia Reisser of the University of Western Australia stated in the study.
The expeditions were carried out in the South and North Pacific, the south Atlantic, Indian Ocean and waters around Australia.
Currents moving plastic around
Much of the debris detected included fishing lines and gear, bottles, buckets, bags and foamed polystyrene.
The study warned that more vigilance is needed to monitor the amounts of plastic entering the world’s oceans.
“Rates of new plastic entering the ocean are unknown, as well as outputs of plastic due to beaching, sinking and … degradation.”
The scientists noted that winds and surface currents are carrying plastics to all kinds of places showing that “plastic pollution moved more easily between [oceans] and between hemispheres than previously assumed.”
Researchers noted that in some of the five large ocean gyres – circular currents that stir up plastics in a set area – there was more plastic than marine life.
The scientists said more plastics need to be recycled, noting that only five per cent of the world’s plastic is presently being recycled.