‘A confronting amount’: CSIRO study finds 14 million tonnes of plastic on ocean floor

Plastic and other garbage settled at the bottom of the Adriatic Sea.

Plastic and other garbage settled at the bottom of the Adriatic Sea. Photo: Getty

Every drink bottle we buy, face scrub we use and chip packet we finish results in tiny plastics entering the ocean.

But where are these tiny micro-plastics, exactly?

Are they floating around on the ocean’s surface, waiting to be scooped up by a surfer?

Or are they stuck in the tummies of turtles or seabirds?

A new study by the CSIRO, Australia’s national science agency, has estimated up to 14 million tonnes of micro-plastics have sunk to the bottom of the ocean floor.

The peer-reviewed research, published on Tuesday, is the first global estimate for micro-plastics on the seafloor.

Dr Britta Denise Hardesty, team leader with CSIRO’s Oceans and Atmosphere, said 14 million tonnes of micro-plastics was a “huge amount, especially when you think about how tiny all those bits are”.

To put it into perspective: Imagine five carrier bags stuffed with plastic dotted along every single metre of coastline around the world, excluding Antarctica.

The piles of bags would sit on every Australian beach, along Italy’s Amalfi Coast, around Vietnam’s Ha Long Bay, and all around Canada’s coastlines and beyond.

Now imagine someone pushing those bags into the ocean, and letting them sink into the darkness.

“It’s a confronting amount, and hopefully it provides a reasonable wake-up call,” Dr Hardesty told The New Daily.

“We’re finding them hundreds of kilometres offshore and thousands of metres deep – more micro-plastics than has been found by lots of other studies.”

Where are these tiny plastics coming from?

“Micro-plastics come from the same place as plastics,” Dr Hardesty said, adding “micro just means they’re smaller than 5mm”.

“It’s really just small plastic from single-use items, consumer goods, industry or fishing-related goods, cosmetics, micro-beads, agriculture, aquaculture, household waste, everything.”

Many of these tiny plastics end up in our oceans via stormwater drains, sewage systems, sea-based activities, littering, things falling off the backs of trucks, and improper waste management where people intentionally dump rubbish straight into the sea or rivers.

They often end up in the stomachs of marine animals like dolphins or fish, while bigger pieces of plastic can be just as dangerous.

“Masks that have those little straps can tangle the feet and legs of sea birds and things like that,” Dr Hardesty said.

“Rubber gloves might be more likely to look like a jellyfish that could be mistakenly eaten by turtles if they end up in the ocean.”

The World Economic Forum estimates one garbage truck of plastic alone is dumped into the ocean every minute of every day.

It estimates there could be more plastic in the ocean than fish by 2050.

The missing piece

Although the CSIRO’s findings are troubling, perhaps what’s more concerning is the answer to the following question: Where is the rest of the missing plastic?

Compared to the tonnes of plastic entering the ocean every day, Dr Hardesty said 14 million tonnes on the ocean floor was “just a drop in the ocean”.

“Where is all the missing plastic? Is it in the stomachs of animals? Is it floating on the surface?” she said.

“I’d say most of it is on our coastlines.”

Sand covered garbage that flows from the sea at Kedonganan beach, Bali, Indonesia in 2018. Photo: Getty

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