Sun, Apr 29, 2018 - Page 7 News List

‘Wake-up call’: Microplastics found in Great Australian Bight sediment

Scientists say governments and corporations need to ‘legislate and incentivize’ to tackle ocean plastics

By Graham Readfearn  /  The Guardian

Illustration: June Hsu

Plastic has been found in ocean-floor sediments 2km below the surface in one of Australia’s most precious and isolated marine environments.

Scientists at the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia’s national science agency, discovered the microplastic pieces while analyzing samples taken hundreds of kilometers offshore at the bottom of the Great Australian Bight — a so-called “pristine” biodiversity hotspot and marine treasure.

Conservationists and scientists said the discovery off the South Australian coast should act as a “wake-up call” for governments and corporations to cut unnecessary use of plastics and to “legislate and incentivize” to tackle the growing ocean plastics problem.

“This points to just how ubiquitous plastics are in our environment. Even in deep-sea sediments around Australia, which is a developed country, we still find plastic — anthropogenic waste — from the bottom of the sea to the surface,” said Denise Hardesty, a principal research scientist at CSIRO and a member of the team analyzing the sediments. “Wherever you are, the organisms passing through those areas will have come in contact with it — whether it was a fishing line or a plastic bag that’s broken down into thousands of tiny pieces.”

“This is hundreds of kilometers offshore at a couple of kilometers of depth — that’s pretty confronting that, even there, we find it,” she added. “This stuff is everywhere.”

The sediments were analyzed using a red dye that causes any plastics to fluoresce under special light. The pieces detected were at least 10 micrometers wide — about the same width as very fine wool.

CSIRO scientists are doing further analysis and a scientific paper is being prepared for submission to a journal.

Microplastics have been found in several less remote seabed areas around Australia and other parts of the world.

CSIRO researchers last year reported that they had found plastic pieces in sediments taken from Derwent River in Tasmania. The same team has found plastic fibers in the digestive tract of mussels from the same river.

Jennifer Lavers, of the Institute for Marine and Antarctic Studies at the University of Tasmania, said she was not surprised that plastic had been found in the bight “because there are multiple studies from around the world finding microplastics and even nanoplastics in sediments throughout the bottom of the world’s oceans.”

“Should it worry us? Absolutely! The smaller the pieces, the more species there are to consume it,” she said. “Everything that is tiny is at the base of the food web, so it’s not an issue of just an albatross swallowing a cigarette lighter or a sperm whale swallowing a big chunk of net, you now literally have microplastics being eaten by corals, sea cucumbers, clams and mussels, and zooplankton at the very base of the food web.”

“You have all levels of the food web infiltrated with this stuff,” she added. “Everywhere and anywhere that the plastic goes, the chemicals follow.”

Microplastics and microfibers are so ubiquitous in our air and water that the CSIRO researchers had to go to extreme lengths to reduce any contamination of their sediment samples from outside sources.

Equipment had to be pre-rinsed with deionized water, laboratory solutions had to be filtered, analysis took place in a fume hood and personnel wore clothes made from natural fibers. Air monitoring was also carried out to find laboratory areas with the least amount of airborne plastics.

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