Planktonic copepods are the most abundant animals in the ocean and one of the key players in the global biochemical process. Previous modelling studies have shown that zooplankton ingesting microplastics (MPs) disrupts bio-carbon pumps and accelerates the loss of oxygen from the global ocean.
Recently, a new study by a joint scientific research team from China and Denmark found that when planktonic copepods encounter microplastics in the water environment, they may “pick fat and pick thin”, and refuse to swallow most of the microplastics through “taste identification”. The results were published online on April 27 in Environmental Science and Technology.
In this study, the team used small-scale video observations and bottle culture to study the behavioral response and feeding rate of planktonic copepods when exposed to microplastics with different characteristics.
The scientific team found that copepods rejected 80% of microplastics after contacting microplastics with mouthparts, essentially showing a taste identification, indicating that copepods have a function similar to taste identification. Further studies found that the high retention rate of microplastics in the culture vessel was not related to the type, shape, presence of biofilm, adsorption of pollutants (pyrene), etc. of the microplastic polymer, which indicated that microplastics were not suitable for feeding copepods. The taste discrimination function of copepods after capturing microplastics is the main sensory mechanism by which microplastics are retained.
Planktonic copepods can “taste distinguish” microplastics. Image from the paper
The research team said that a large number of microplastics have been found in marine waters. But this finding suggests that the risk of ingesting microplastics in planktonic copepods is relatively low. (Source: China Science Daily Zheng Jinwu)
Related paper information:https://doi.org/10.1021/acs.est.2c00322