Microplastics are small plastic particles less than five millimeters long. They can come from larger plastic pieces which break down into smaller pieces, as well as microbeads (tiny pieces of plastic added to beauty products for exfoliating purposes) and resin pellets from plastic manufacturing. They may take 50-600 years to break down and have been found in animals and in drinking water.
Scientists have found that microplastics can have negative health effects on animals, including humans.
In a recent study, an international team of scientists examined the effect of microplastic ingestion on gut microbiome communities in wild animals. As the study says, microbiomes are essential to host nutrition, physiology, immune faction, development and even behavior. As such, previous studies have found that microplastics may negatively affect microbiomes, with resulting negative health effects. However, a closer look at the effect of microplastics on wild populations has not previously been studied.
Researchers counted and weighed the microplastics present in two different seabird species: Cory’s shearwaters (Calonectris borealis), from Portugal, and northern fulmars (Fulmarus glacialis), from Canada. Both species are known to ingest plastic debris, and their distributions span a wide range across both hemispheres.
"Until now there was little research on whether the amounts of microplastics present in the natural environment have a negative impact on the gut microbial health of affected species," says Gloria Fackelmann, the study’s lead author. The scientists studied the microbiome of the gut, as well as of the proventriculus (a region of a bird’s stomach between the crop and the gizzard), to obtain a thorough picture of the microbiome’s health throughout the birds.
Their results supported previous findings that chronic microplastic ingestion is associated with an imbalance of microorganisms in the intestines, or “gut dysbiosis.” Gut dysbiosis is an indicator of an unhealthy microbiome.
"Our findings reflect the circumstances of animals in the wild. Since humans also uptake microplastics from the environment and through food, this study should act as a warning for us," say the authors.