Chemical cocktail suppresses periwinkles’ ability to avoid crabs and disrupts food chain

Toxins leaching from microplastics leave shellfish at the mercy of predators, research has found. The chemicals completely suppress the ability of the periwinkles to detect and avoid the crabs that eat them. Microplastics plague the world’s rivers and oceans and absorb poisonous chemicals from the water. Previous work has shown mussels are harmed by these toxins when they eat microplastics, but the latest study is the first to show disruption of the relationship between predator and prey. This is likely to disrupt the entire food chain, researchers say. Microplastics are known to be present in seafood, as well as tap water, honey and salt and probably many other foods. Humans are known to consume microplastics but the impact on health is as yet unknown.

The research, published in the journal Biology Letters, looked at the common periwinkle. It grazes on algae but is eaten by crabs. Its central role in the food chain makes it a keystone species on beaches. It is also widely eaten by people.

When a crab approaches a periwinkle, chemical cues usually lead the shellfish to take evasive action, such as withdrawing into their shells or hiding under rocks. But, in the lab, when the periwinkles were kept in water with microplastics collected from a beach near Calais in France, they failed to react. “The whole set of behaviours are totally inhibited,” said Prof Laurent Seuront, at the National Centre for Scientific Research in northern France. “It is worrying news. If the periwinkles are not able to sense and escape from the predator, they are more likely to disappear and then to disturb the whole food chain.” Click here to read the paper