Reduced feeding also means the sediment is being reworked less, the research found. The condition of the sediment could fall, leading to a decline in the communities that live in it. Wright said: “If worms in contaminated environments were to reduce feeding levels by an amount comparable to that seen in the lab, it would mean significantly less turnover of sediment. In an area the size of the Wadden Sea, for instance, sediment turnover could drop by more than 130,000 liters each year.”
“We believe our study has highlighted the need to reduce the amount of plastic waste and therefore microplastics which enter our seas,” University of Exeter professor Tamara Galloway said. “Plastics are enormously beneficial materials. However, if marine plastic pollution continues to increase, impacts such as those demonstrated in our laboratory studies could occur in the natural environment. It is therefore important that we prevent the accumulation of plastic and microplastic debris in marine habitats through better waste-handling practices and smarter choices in the materials we use.”
A separate report, from Mark Anthony Browne on work performed at Plymouth University, showed microplastics can transfer harmful chemicals to lugworms, including hydrocarbons, antimicrobials and flame retardants. Due to its role as a prey species, lugworms could pass these chemicals up the food chain to top predators such as fish.
“These chemicals are persistent, meaning they could accumulate in the tissue of organisms and take a long time to break down,” said Richard Thompson of the Plymouth University School of Marine Science and Engineering, who led the project. “Our laboratory studies provide the first clear evidence that microplastics could cause harm and show that this could result from both the physical presence of ingested plastic and chemical transfer. Our next steps will be to establish the full implications of these findings for organisms in natural habitats.”