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Plastic — cheap, strong and durable — is a versatile material we’ve embraced for 70 years. Yet most of the plastic ever created is still with us today. And it’s choking life in our oceans, where the bulk of it ends up.

By 2025, the oceans could contain one tonne of plastic for every three tonnes of fish.

Oceans of plastic

All life on Earth is deeply linked to ocean ecosystems. They provide food, most of Earth’s oxygen, and much more besides. Vast and timeless, the oceans’ ability to absorb human pollution once seemed limitless.

No longer.

Today coastal countries send roughly eight million tonnes of plastic into oceans every year — five grocery bags for every 30 centimetres of coastline worldwide. Every 11 years, global plastic production doubles.

A view of marine debris from below, as fish or sea turtles might see it. Image: U.S. National Oceanic and Atmospheric Administration.

Out of sight, out of mind?

Scientists are trying to understand where it all goes. Some is swept into circular ocean currents, called subtropical gyres. They churn and collect plastic into five immense areas, including the Great Pacific Garbage Patch. Visitors say it’s like sailing through ‘plastic soup’.



In 2014, The 5 Gyres Institute published the first global estimate of marine plastics – 270,000 metric tons from 5.25 trillion particles. Video: Anna Cummings.

Though vast, the five ocean garbage patches are just the tip of the iceberg. Like smog particles through air, plastic spreads throughout our oceans. It’s been found in the remotest places — embedded in Arctic ice, in the deepest ocean trenches.

Deadly ghost nets lurk

Some of the biggest and most harmful pieces of plastic pollution are discarded fishing nets. Called ghost nets, they can be kilometres long. They entangle and trap marine creatures including turtles, whales and dugongs.

Location of ghostnets across northern Australia. Image: Ghostnets Australia.

Microplastic: a big problem

At the other end of the size spectrum is harder-to-see microplastic pollution. Half a centimetre or smaller, it forms as sun and waves break down bigger pieces. Scientists estimate up to 51 trillion particles of microplastic now pollute the ocean.

Microplastic includes microbeads, tiny plastic particles some health and beauty product makers add to things like toothpaste and face scrubs. One bottle of face scrub may contain 300,000 microbeads. They slip through filter systems and into the ocean, to become a major pollution problem.