Mussel beds act as traps for microplastics dumped in the ocean

Mussel beds act as traps for microplastic pollution dumped in the ocean by slowing the sea water flowing over them, research shows

  • Experts experimented with flowing water over different mussel reef structures
  • When the mussels clumped together like in nature, the flow became turbulent
  • This increased threefold the amount of microplastic ingested by the mussels

Mussel beds act as traps for microplastic pollution dumped in the ocean by slowing the sea water flowing over them, a study has concluded.

Researchers from the University of Plymouth used a series of experiments to explore how the plastic particles get into different types of reefs formed by blue mussels.

When the mussels clumped together as they do in nature, the team found that the structure of the reef slowed the sea water flowing over it.

This increased water turbulence and resulted in a three-fold rise in the amount of plastic ingested by the mussels.

Researchers suggest that natural reef structures can foster conditions that make them natural sinks for plastics and other forms of pollution.

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Mussel beds act as traps for microplastic pollution dumped in the ocean by slowing the sea water flowing over them, a study has concluded

‘Species such as the blue mussel are both commercially valuable as seafood but also environmentally important,’ said paper author and marine ecologist Antony Knights of the University of Plymouth.

‘They form natural reefs within marine and coastal settings which enhance biodiversity to such a degree that they are commonly protected under conservation actions.’

‘If they are particularly susceptible to microplastic pollution, there are many potential knock-on effects that we need to be aware of.’

‘Often we look to protect reef-forming species based on who they are,’ Professor Knights added.

‘However, we are not aware of any research that has shown that the physical structure of reef itself […] might also inadvertently increase their exposure to pollutants like microplastic.’

Reef structure, he explained, ‘can help these filter-feeding organisms to be more effective feeders.’

‘With no means of addressing this issue, due to our increasing awareness of the quantity of microplastic in the marine environment, this study offers the first evidence that forming a reef is a double-edged sword for individuals.’

Researchers from the University of Plymouth used a series of experiments to explore how the plastic particles get into different types of reefs formed by blue mussels. When the mussels clumped together as they do in nature, the team found that the structure of the reef slowed the sea water flowing over it

During the study, mussels were placed in controlled clusters in a water flume and exposed to different wave speeds.

Microplastics were added to the water, allowing researchers to assess the risk of particle ingestion under different scenarios.

The full findings of the study were published in the journal Environmental Research Letters.

URBAN FLOODING IS FLUSHING MICROPLASTICS INTO THE OCEANS FASTER THAN THOUGHT

Urban flooding is causing microplastics to be flushed into our oceans even faster than thought, according to scientists looking at pollution in rivers.

Waterways in Greater Manchester are now so heavily contaminated by microplastics that particles are found in every sample – including even the smallest streams.

This pollution is a major contributor to contamination in the oceans, researchers found as part of the first detailed catchment-wide study anywhere in the world.

This debris – including microbeads and microfibres – are toxic to ecosystems.

Scientists tested 40 sites around Manchester and found every waterway contained these small toxic particles.

Microplastics are very small pieces of plastic debris including microbeads, microfibres and plastic fragments.

It has long been known they enter river systems from multiple sources including industrial effluent, storm water drains and domestic wastewater.

However, although around 90 per cent of microplastic contamination in the oceans is thought to originate from land, not much is known about their movements.

Most rivers examined had around 517,000 plastic particles per square metre, according to researchers from the University of Manchester who carried out the detailed study.

Following a period of major flooding, the researchers re-sampled at all of the sites.

They found levels of contamination had fallen at the majority of them, and the flooding had removed about 70 per cent of the microplastics stored on the river beds.

This demonstrates that flood events can transfer large quantities of microplastics from urban river to the oceans.

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