Microplastics major problem for Great Barrier Reef

Fraser Barton | August 3, 2022

Over 500 microplastics have been found in Great Barrier Reef waters after a three year study highlighted the growing risk to marine life.

Researchers from James Cook University and the Australian Institute of Marine Science conducted 66 surface seawater tows using a plankton net near the SS Yongala shipwreck, southeast of Townsville between September 2016 and September 2019.

They found a total of 533 synthetic and semi-synthetic plastic items across all tows, with all but one net gathering samples.

Analysed samples found 92 per cent of fragments and fibres were microplastics.

“Similar to our results, most microplastics previously detected in both GBR waters and coral reef fishes have been identified as microfibres of textile origin, likely derived from clothing and furnishings,” Dr Cherie Motti from the institute said. 

The researchers estimate by 2030 there will be a yearly input of between 20 and 53 million metric tonnes of plastic into aquatic eco-systems, with the associated risks likely to increase by roughly 50 per cent in some marine environments.

James Cook University’s Professor Mark Hamann said microplastics less than 5mm in size were concerning due to their continuous intake and retention in marine organisms.

Fellow researcher and JCU PHD candidate Michaela Miller said these plastics were found in the global marine environment, and plastic concentrations were significantly influenced by extreme weather events and increases in wind speed and river discharges.

“Despite peaking immediately following extreme weather events, the overall trend of plastic contamination did not change over the three years of study, suggesting continued and chronic risks of plastic exposure to marine organisms,” she said.