Antibiotic pollution harms pond snails’ ability to learn
“If we find this effect in snails, it is highly likely that antibiotics are having similar effects on other aquatic animals” – Sarah Dalesman.
Water polluted with antibiotics can stop pond snails from forming new memories by disrupting their gut microbiome, a new study has found.
Researchers from the University of East Anglia and Aberystwyth University found that snails in clean water were much better at learning to avoid contaminated food than those in water polluted with high concentrations of antibiotics.
The study adds to the growing body of research on the negative impact of antibiotic pollution, with the researchers calling for more to be done to stop the chemicals entering the environment.
During the study, the pond snails (Lymnaea stagnalis) were given carrot juice, a favourite food, which had been paired with a chemical (potassium chloride) that is an aversive stimulus for the species.
The snails in the clean water quickly learned that the carrot juice was no longer safe to eat and avoided it. However, the snails in the polluted water failed to remember. This impact on their memory could hurt their survival chances in the wild.
Sarah Dalesman, a lecturer in freshwater biology at Aberystwyth University and co-author of the study, said: “Previous research has found pond snails have to learn about predators, what is good or bad to eat, and even remember who they have mated with.
“Anything that interferes with their memory will reduce their survival.”
The study found that the antibiotics in the water had changed the gut microbiome of the snails, altering the levels of certain bacteria that have been found to have a connection with memory formation in other animals.
Previous studies have shown a link between the gut microbiome and brain function in terrestrial species, but this is the first time that this has been shown to be the case in pond snails.
The concentration of antibiotics the snails were exposed to was similar to those detected in freshwater in the UK and other parts of the world.
Dr Dalesman added: “If we find this effect in snails, it is highly likely that antibiotics are having similar effects on other aquatic animals.
“We hope this study prompts greater emphasis on the importance of healthy gut microbiomes for wildlife and increases efforts to reduce the chemicals entering our environment.”
The study has been published in The ISME Journal: Multidisciplinary Journal of Microbial Ecology.
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