A study published today in IOP Publishing's journal Environmental Research Letters reveals that centimetre-sized plastic fragments are increasing much faster than larger floating plastics in the North Pacific Garbage Patch [NPGP], threatening the local ecosystem and potentially the global carbon cycle.
The research, which draws from not-for-profit The Ocean Cleanup's systematic surveys of the NPGP between 2015 and 2022, found an unexpected rise in mass concentration of plastic fragments that are likely new to the region, and not resulting from degradation of already present objects. The researchers hypothesise that these fragments from the break-down of decades old plastics discarded globally are now accumulating and exponentially increasing in this remote region of the Pacific Ocean.
The study examines 917 manta trawl samples, 162 mega trawl samples, 74 aerial surveys, and 40 cleanup system extractions from 50 individual expeditions between 2015 and 2022.
Key findings include:
Plastic fragments rose from 2.9kg per km2 to 14.2kg per km2 in 7 years
74% - 96% of this rise may be originating from foreign sources.
Small debris hotspots increased in concentration from 1 million per km2 in 2015 to over 10 million per km2 in 2022
Per km2 , the average number of every size class of floating plastics has significantly increased:
- Microplastics (0.5mm-5mm) risen from 960,000 to 1,500,000 items
- Mesoplastics (5mm-50mm) risen from 34,000 to 235,000 items
- Macroplastics (50mm-500mm) risen from 800 to 1,800 items per km2
The volume of plastic debris in the region surpasses that of living organisms, threatening the ecosystem not only by the ingestion or entanglement of plastic by marine life, but also potentially impacting the global carbon cycle because of zooplankton grazing affected by the presence of floating microplastics. Due to the increase in floating plastics, endemic marine animals are now in direct competition with new species that have colonized plastic debris and drifted to this remote part of the ocean.
Laurent Lebreton, lead author of the paper says: "The exponential rise in plastic fragments observed in our field studies is a direct consequence of decades of inadequate plastic waste management, leading to the relentless accumulation of plastics in the marine environment. This pollution is inflicting harm on marine life, with impacts we are only now beginning to fully grasp. Our findings should serve as an urgent call to action for lawmakers engaged in negotiating a global treaty to end plastic pollution. Now, more than ever, decisive and unified global intervention is essential."
The researchers emphasise that, while countries are prioritizing upstream plastic pollution prevention, the interception and removal of already present plastics from the global marine environment is essential to urgently mitigate the generation of increasingly smaller plastic fragments in the ocean for decades to come.
