Today, more and more researchers are paying attention to how the pollution of the world with microplastics (recall that all plastic particles with a diameter of less than five millimeters are referred to it) affects established ecosystems. Basically, we are talking about ocean pollution, which has reached alarming proportions.
Scientists have previously found that plastic affects marine life, birds, and even humans.
True, in such works, mainly changes in the eating habits of animals are considered, and not the transformation of their behavioral characteristics. Scientists at the French National Center for Scientific Research set out to find out how pollution affects the classic predator-prey relationship.
Let us explain that this is an evolutionarily determined model of behavior. For many years, participants in such systems that exist today in all ecological niches have developed appropriate adaptations and behavioral habits. However, a merciless environmental factor can shake even such a well-established, long-familiar way of life for animals.
The objects of the new study were gastropods called common littorina, or sea snails (in France, by the way, they are eaten).
These creatures most of the time "graze" on the rocks covered with algae. At the same time, they inevitably absorb the microplastics particles stuck in them.
Previous work has shown that microplastics absorb hazardous chemicals and heavy metals from water. Accordingly, together with its particles, such toxic components also get to the algae.
When littorina eats contaminated food, all these "seasonings" are also sent to her body.
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To find out what impact they have, scientists collected several sea snails off the coast of Calais and sent them to a laboratory, where they simulated the conditions of a polluted ocean. They also collected crabs - the main hunters for these mollusks.
As it turned out, the littorians who dined on toxic microplastics did not react properly to the presence of the threat. Usually, when they see danger, they pull their bodies into the shell to avoid attack. But in this case, the sea snails did not even try to hide from the crabs in their shelter.
The authors of the work believe that this is due to the toxic effect on the nerves of sea snails, and the damage is probably caused not by the microplastic itself as such, but by the heavy metals that it had previously absorbed.
By the way, in their experiments, scientists "tuned" the level of pollution in such a way that it was equivalent to that observed in typical coastal areas. That is, they simulated real conditions.
“The entire set of behavioral [reactions of sea snails] were completely suppressed. This is disturbing news. If littorians cannot sense [danger] and escape from a predator, they are more likely to disappear, disrupting the entire food chain, "- said the author of the work, Professor Laurent Seuront.
This appears to be not the only example of pollution-induced behavioral change. In a scientific article published in the journal Biology Letters, scientists note that such biological effects can have serious consequences for marine ecosystems.
However, not only marine. Other work on pollution has shown that mosquitoes carry microplastics from water to land.
Yulia Vorobyova