Microplastic hotspots discovered

The highest level of microplastics ever has been discovered on the seabed, exposing how most waste sinks to the deep ocean floor.

Scientists found up to 1.9 million pieces of microplastic – usually 5mm or less which block sea animals’ digestive tracts – in a thin layer covering just one square metre of the seafloor, according to Sky News.

More than 10m tonnes of plastic waste enters the world’s oceans each year, with about 99% thought to accumulate in the deep ocean, but it had not previously been clear as to where that ended up.

Published in the journal, Science, the research found how deep-sea currents act as conveyor belts, transporting the tiny plastic fragments across the seafloor.

The currents bring the microplastics together in huge sediment groupings called “microplastic hotspots” say the researchers from The University of Manchester, Durham University, the UK’s National Oceanography Centre, the University of Bremen in Germany, and sea exploitation agency, Ifremer, in France.

Dr Mike Clare, of the National Oceanography Centre, who was a co-lead on the research, says: “Our study has shown how detailed studies of seafloor currents can help us to connect microplastic transport pathways in the deep-sea and find the ‘missing’ microplastics.

“The results highlight the need for policy interventions to limit the future flow of plastics into natural environments and minimise impacts on ocean ecosystems.”

The team collected sediment samples from the seabed of the Tyrrhenian Sea, part of the Mediterranean Sea, and compared them with detailed models of deep ocean currents and seafloor maps.

They found the microplastics either settle out slowly when they enter the sea, or can be quickly transported by powerful underwater avalanches that travel down submarine canyons to the deep seabed where bottom currents then pick out the fibres and fragments and group them into large sediment drifts.

Deep ocean currents also carry oxygenated water and nutrients, meaning the seabed microplastic hotspots can house important ecosystems that can consume or absorb the microplastics.

The new research came out as Sky’s ocean rescue investment fund, Sky Ocean Ventures, announced it is part of a group that has invested £2m in the world’s first microplastic alternative that uses no chemicals whatsoever.

Researchers at Xampla, a University of Cambridge spin-off aiming to reduce microplastic pollution, developed the new material using widely available plant protein.

Some alternatives are already on the market, but they are based on plant polysaccharides and require chemicals to bind them which still pollutes the world’s oceans.

The new material is entirely natural, enabling it to decompose quickly and completely in the environment, according to Sky News.

Protein experts Professor Tuomas Knowles and Dr Marc Rodriguez Garcia were inspired by spiders creating silk, with the new material using a similar method to transform the plant protein into plastic-like materials such as films, gels and capsules.

Vanessa Draper, director of Sky Ocean Ventures, says: “We have been investing in innovations to end the devastating flow of plastic into the sea for the last two years.

“We’re excited by Xampla’s potential to replace synthetic microplastics hidden inside everyday products from detergents to paints.

“Consumers often aren’t aware of these ‘hidden plastics’ and have little ability to reduce their use of them, so a new sustainable materials approach is needed.”

Sky Ocean Venture’s investment, along with Amadeus Capital Partners, Cambridge Enterprise and the University of Cambridge Enterprise Fund VI, will enable Xampla to develop its prototype material into products.

Its initial target is the £9.5bn microencapsulation market, in which manufacturers of home and personal care products currently use synthetic polymer capsules, which the EU is considering banning.

Cosmetics Europe, the trade body representing the European cosmetics and personal care industry, said a restriction of microplastics in both rinse-off and leave-on products would affect 24,172 formulations, resulting in a loss of revenue of £10.5bn a year.

The UK banned the sale of rinse-off cosmetics and personal care products containing microbeads in 2018, but they are present in many other household and industrial products, according to Sky News.

Simon Hombersley, Xampla chief executive, says: “Our mission is to reduce the impact of single-use plastic, and our initial commercial focus is on intentionally-added microplastics.

“With our new plant protein material, we are committed to helping manufacturers make the transition from traditional plastics to high performance alternatives that protect the planet.”

Seabed currents sweep the microplastics up into a hotspot. Pic: Science journal

Comments are closed.