Studies have found that plastic additives can cause hermit crabs to become overactively active

Marine pollution has many consequences for marine life, including seemingly affecting the behaviour of hermit crabs. A study published Tuesday in the Marine Pollution Bulletin showed that low concentrations of a common plastic additive called oleate amides speed up crabs' breathing, suggesting they would feel excited and attracted. This is another example of ocean plastic disrupting ecosystems and wildlife. Earlier this month, a separate study detailed the significant and heartbreaking damage that all the plastic we dumped in the ocean has caused to baby sea turtles.

Oleic acid amide bears striking resemblance to oleic acid, a chemical released during the breakdown of invertebrates known as arthropods. Paula Schirrmacher, a phD student at the University of Hull in the UK, said the additive confused the hermit crabs, who had been studying climate change and the effects of plastic on these small crustaceans.

Schirrmacher said in a statement: "As scavengers, hermit crabs may mistakenly believe that oleic acid amide is a food source. This study suggests that leaching of additives may play an important role in the attraction of marine organisms to plastics. "Oleamide has been thought to be a sex pheromone for clean shrimp, and this study shows that this pair of hermit crabs is also true. It's worth noting that oleamide has different effects on humans — some people use this organic compound as a sleep aid.

The University of Hull study highlights a sobering reality. According to the International Union for Conservation of Nature, at least 8 million tons of plastic flow into our oceans each year, from surface waters to deep-sea sediments. To explore how marine wildlife reacts to the smell emitted by plastic, the team collected 40 crabs off the coast of Yorkshire, England, and transported them to the university's aquarium. There, they measured how the creatures breathed after injecting oleic acid amide into their seawater habitat. Schirrmacher said: "Our study shows that oleic acid amide attracts hermit crabs. His research focuses on how climate change changes the chemical cues on which aquatic organisms depend to guide their environment.

"The large number of plastic additives that have the potential to mimic the natural information chemicals of various species poses a multifaceted problem that urgently requires further investigation to initiate mitigation measures," the study said. ”

A study by a different team last year found that plastic impaired the cognitive abilities of hermit crabs, affecting their ability to select and enter the optimal shell to protect their fragile exoskeletons.