Transfer of microplastics in plankton food chains

Aug. 28 () –

Japanese scientists have conducted a pioneering study that provides field evidence of the transfer of microplastics along marine planktonic food chains.

Microplastics widely distributed in the ocean are easily ingested by marine organisms, particularly zooplankton, whose food particles are similar in size to microplastics.

Chaetognaths, typical carnivorous zooplankton of the ocean, feed mainly on copepods. These play a crucial role in linking secondary producers (such as copepods) with higher trophic level organisms within the food chain.

Recently, a research team led by Professor Sun Xiaoxia from Jiaozhou Bay Station in the Institute of Oceanology of the Chinese Academy of Sciences (IOCAS) conducted a pioneering study on the seasonal characteristics and risks of microplastic ingestion by chaetognaths in Jiaozhou Bay based on field observation data.

The study was published in the Journal of Hazardous Materials.

The researchers assessed the impact of copepods on microplastic ingestion by chaetognaths. Copepods are the main prey of chaetognaths.

The results indicated that there was no seasonal variation in the ingestion of microplastics by chaetognaths.The contamination load index (PLI) of microplastics in chaetognaths was relatively low, while both the polymeric hazard index (PHI) and the potential ecological risk index (PERI) were relatively high.

A further comparison between chaetognaths and copepods showed that the amount of microplastics in chaetognaths was positively correlated with the abundance of copepods and the amount of microplastics in copepods.

“It was found that The microplastics ingested by the chaetognaths were very similar to those of the copepodspredominantly fibrous in shape, 101 to 400 picometers in size, and polyester in polymer type,” said Meng Liujiang, first author of the study and a researcher on Sun’s team.

Long-term exposure and ingestion of microplastics by higher trophic level organisms may lead to a continuous accumulation of microplastics within their bodies. Biomagnification factor calculation showed that chaetognaths have a much higher individual-level accumulation of microplastics in the copepod-chaetognath food chain, suggesting a potential risk of biomagnification.

“Our work provides critical field evidence on the transfer of microplastics through marine planktonic food chains, laying an important foundation for future research into the fate of microplastics in the ocean and their potential ecological risks“said Professor Sun, the corresponding author.