Mussels begin to lose control when exposed to microplastics, the research found, in the latest example of the harmful effects of plastic contamination on marine life.
When blue shells were exposed to doses of non-biodegradable microplastic parts for 52 days, they lost about half of their power to cling to surfaces. The weakening of their attachment appears to be the result of the production of much less bisexual threads, thin fibers produced by shells that allow them to attach to rocks, ropes and other submarine environments.
The research conducted in the seawater laboratory in Portereri in Northern Ireland and published in the journal Environmental pollution is one of the first to study the effects of microplastics on marine organisms.
Microplastics have been found throughout the world in a wide range of environments, from groundwater and seawater to flying insects and are probably even in the air we breathe. Last year, a study revealed microplasty in human faeces for the first time.
Some of them are microplastics that are deliberately produced, for example as microbiologists in cosmetics, but most of them are due to the breakdown of the larger pieces of plastic scrap. There are a myriad of microplastic sources – for example, synthetic clothing can shed tiny fibers when it is washed – making it difficult to remove them from use.
If shellfish is losing its grip in the wild, as well as under study conditions, the effects will be felt outside the population of molluscs. Mussels cling to form cliffs that help them to grow and shelter a host of other marine life and plants that play an important role in the marine ecosystem.
Dannielle Green, senior lecturer in biology at the University of England, Raskin, who led the research, said: "The tinyness is vital for mussels to form and maintain reefs without being destroyed by hydrodynamic forces. Reduction of biseal filaments in the wild can lead to cascading impacts on biodiversity, as well as reducing aquaculture yields, as shells are more likely to be washed away by waves or strong tides. "
Microplastics also appear to cause a strong immune response in shells and affect their metabolism, researchers found. They measure the vertical force required to turn off the shell from the attached position and found that for those exposed to non-biodegradable microplasty over a period of 52 days, the required force was only half the required in the control sample without such exposure. There were also effects of exposure to biodegradable plastics, but they were less marked.