Something alarming is happening beneath the ocean’s surface and although it is not visible, it is not without consequences. Scientists have confirmed that powerful underwater avalanches, travelling at speeds of up to 8 meters per second, are carrying massive amounts of microplastics into the darkest depths of the oceans, over 3,200 meters below the surface. Plastics are silently polluting all the marine ecosystems that need clean, oxygen-rich water to survive and are thus endangering billions of people who rely on marine life for food. Researchers from the UK’s National Oceanography Centre and the University of Manchester have revealed that these underwater avalanches, also known as turbidity currents, are playing a key role in scattering microplastics across the ocean floor. The initial discovery was made when a microplastics hotspots study was conducted in the Tyrrhenian Sea.
Microplastic from your clothes pollutes the oceans
During further research aboard the Royal Research Ships, RRS James Cook and RRS Discovery, at Whittard Canyon in the Celtic Sea, researchers watched in real time as a turbidity current moved a “huge collection” of sediment at a speed of over 2.5 meters per second to depths of over 1.5 kilometers under the water’s surface.
Samples collected from that movement showed that apart from mud and sand, there was a substantial amount of microplastic fragments and microfibres. Further analysis revealed that many of those microplastics came from textiles and clothing that had not been properly filtered at domestic wastewater treatment plants, and had subsequently easily entered rivers and oceans.
According to Dr Ian Kane, a geologist and environmental scientist from the University of Manchester, the turbid currents carry oxygen and nutrients that sustain deep sea life and their contamination with microplastics poses a serious threat.
“These biodiversity hotspots are now co-located with microplastic hotspots, which could pose serious risks to deep-sea organisms. We hope this new understanding will support mitigation strategies going forwards,” said Dr Kane.
This was the first occasion that the dumping process had been observed and documented as it occurred. According to researchers, the findings illustrate the threats that microplastics pose to the environment and marine ecosystems, and confirm the urgent need for stronger anti-pollution measures.
Plastics will outweigh all the fish in the seas
According to a UNESCO report, plastic waste accounts for 80% of the entire marine pollution, with 8 to 10 million tonnes of plastic entering the oceans annually. Consequently, there are an estimated 50 to 75 trillion microplastics and plastic debris in the oceans. By 2050, researchers state that plastics will outweigh all the fish in the seas. It is estimated that every year 19-23 million tonnes of plastic leaks into aquatic ecosystems such as lakes, rivers, seas and land-based water sources. However, what is seen floating and properly disposed of represents less than 1% of the total plastic pollution in the ocean. On average, each square kilometer of sea bed contains an estimated 70 kilograms of plastic waste.
Marine species are endangered
Ocean plastic pollution endangers marine life and 17% of the marine species that are affected by ocean plastic feature on the International Union for Conservation of Nature’s Red List of threatened species. A 2020 study revealed that 914 marine species have encountered marine debris by ingestion or entanglement, with 92% of those encounters involving plastics, according to The Ocean Cleanup.
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At the Great Pacific Garbage Patch – the world’s largest accumulation of plastic – 84% of plastic samples contained toxic chemicals.
“Microplastics on their own can be toxic to deep-sea life, but they also act as ‘carriers’, transferring other harmful pollutants such as perfluoroalkoxy alkanes (PFAs), ‘forever chemicals’, and heavy metals which makes them an environmental ‘multi-stressor’ that can affect the entire food chain,” explained Dr Peng Chen, the study’s lead author from the University of Manchester.
Soaring economic costs
Plastic pollution is also hampering the global economy and those who depend on the oceans for their livelihoods. According to a report by the UN Environment Programme, oceans provide food to over 3 billion people and annually generate at least $2.5 trillion a year but this is now at risk.
A 2018 Deloitte research estimated that marine plastic pollution costs fisheries, agriculture, tourism, aquaculture, and clean-ups $19 billion annually and this number continues to rise.
By the year 2040, businesses could have to spend $100 billion annually if governments insist they must cover waste management expenses, including recycling. This could trigger an increase in illegal domestic and international waste disposal by businesses seeking to avoid the costs linked to responsible disposal.
See also: Water pollution in the world: major causes and statistics
While speaking at the annual World Economic Forum in 2025, Inger Andersen, the UNEP’s Executive Director, warned that the costs of plastic leakage into the environment may rise to US$281 trillion by 2040, which will be costly to businesses and he called for the Global Plastics Treaty to be urgently finalized and implemented.
