Food availability is crucial for effects of 1-μm polystyrene beads on the nematode Caenorhabditis elegans in freshwater sediments.

Freshwater sediments represent a sink for microplastic (<5 mm) through various processes. Thus, benthic organisms can be exposed to relatively high concentrations of microplastics. Surprisingly, studies on benthic organisms are still underrepresented in the field of ecotoxicological effect assessment of microplastics.

Long-term exposure of a free-living freshwater micro- and meiobenthos community to microplastic mixtures in microcosms.

Microplastics in a wide range of shapes and polymer types (MPs; <5 mm) accumulate in freshwater sediments, where they may pose an environmental threat to sediment-dwelling micro- and meiobenthos. To date, the effects of MPs on those organisms have mostly been studied in single-species experiments exposed to high particle concentrations. By contrast, there have been few investigations of the effects resulting from the long-term exposure of natural communities to environmental relevant MPs.

Food bacteria and synthetic microparticles of similar size influence pharyngeal pumping of Caenorhabditis elegans.

Toxicity tests using the model organism Caenorhabditis elegans have shown that exposure to small microplastics such as polystyrene (PS) beads lead to high body burdens and dietary restrictions that in turn inhibit reproduction. Pharyngeal pumping is the key mechanism of C. elegans for governing the uptake of food and other particles and can be easily monitored by determining the pumping rates.

Bacterial consumption by nematodes is disturbed by the presence of polystyrene beads: The roles of food dilution and pharyngeal pumping.

Microplastics (MPs; <5 mm) released into freshwaters from anthropogenic sources accumulate in sediments, where they may pose an environmental threat to benthic organisms, such as nematodes. Several studies have examined the effects of nano- and microplastics on the nematode Caenorhabditis elegans, whereas reduced food availability was suggested as a possible explanation for the observed inhibitory effects. Therefore, this study should clarify whether micro-beads of different sizes (1.