Experiments show that almost all microorganisms ingest microplastics, but tardigrades avoid them
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Tardigrades (water bears) are known for their resilience, being able to withstand extreme heat and cold, vacuum conditions, strong radiation, etc. A new study has reported that while most microorganisms ingest microplastics , only water bears do not ingest microplastics.
Short-term microplastic effects on marine meiofauna abundance, diversity and community composition [PeerJ]
https://peerj.com/articles/17641/
Microplastics Seem to Be in Every Kind of Animal... Except One : ScienceAlert
https://www.sciencealert.com/microplastics-seem-to-be-in-every-kind-of-animal-except-one
Microplastics is a general term for tiny plastic fragments present in the environment, and are known to enter the human body via food, beverages , etc. Microplastics have already been found in human lungs and testicles , raising concerns that they may pose a health hazard .
In addition, because a large amount of plastic is discarded in the ocean, it is thought that benthic organisms living on the bottom of the ocean are particularly likely to absorb microplastics. Therefore, a research team led by zoologist Flavia de França of the Federal University of Pernampuco in Brazil investigated the impact of microplastics on meiofauna , which refers to benthic organisms with a body length of less than 1 mm.
The team collected samples of meiofauna measuring between 45 microns and 1 mm in length from low-tide beach sediments off the coast of northeastern Brazil, revealing 5,629 organisms, including
The organisms were housed in tanks designed to mimic natural environments as closely as possible, and were kept with 100g of sediment containing varying amounts of plastic particles, some of which are technically classified as 'nanoplastics' - particles with a radius of less than 0.001mm - but the team collectively refer to them all as 'microplastics' as classification by particle size is still under debate.
After leaving the organisms for a while, they were analyzed and found that all organisms except for tardigrades had absorbed the microplastics. It is speculated that the reason that only tardigrades did not ingest the microplastics is because they do not ingest their prey whole, but instead pierce the prey with their long, tube-like mouths (styes) and suck it in.
However, since there are many different types of tardigrades, it is possible that some species may ingest microplastics. In addition, although the tardigrades observed this time did not absorb microplastics into their bodies, it has been reported that microplastics were attached to the surface of their bodies, such as their legs (locomotor system).
by Philippe Garcelon
The findings not only highlight the uniqueness of tardigrades, but also show how even the smallest organisms can be affected by microplastic pollution. Some meiofauna are known to prey on other organisms, suggesting that microplastics may be concentrated up the food chain.
The researchers found no difference in meiofauna density or species richness between the tanks with the highest microplastic concentrations and those without added microplastics. However, they also found counterintuitive results, such as a decline in meiofauna in tanks with lower microplastic concentrations, and further research is needed to understand the underlying mechanisms.
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