Influence of Nano- and Small Microplastics on Ciliated Protozoan Spirostomum ambiguum (Muller, 1786) Ehrenberg, 1835

This study evaluated the uptake of secondary nano- and small microparticles by the protozoan Spirostomum ambiguum, comparing edible (baker's yeasts) and inedible (red latex) particles. Secondary nano- and microplastic particles were prepared from household materials made of four different polymers and served to the protozoans separately and as two-component mixtures in different proportions. The number and content of food vacuoles formed by the protozoan were analyzed using a digital microscope. The microscopic results showed that the protozoans ingested the secondary microplastic particles to a similar degree as the latex microspheres but to a lesser extent compared to the nutritional food-baker's yeasts. At the microplastic concentrations of 1000 and 10,000 particles mL(-1), no food vacuoles were observed inside the cells, which may be a finding of great ecological importance. In the protozoans served two-component mixtures, both microplastics and yeasts were found in the vacuoles formed by the organisms. The egestion of two-component vacuoles by the protozoans was slower than that of vacuoles containing a single component.

Automated summary

The study found that the protozoans ingested secondary microplastic particles to a similar degree as latex microspheres but less compared to baker's yeasts. At higher concentrations, no food vacuoles were observed inside the cells.