The amount of nano- and microplastic in the
aquatic environment rises due to the industrial production of
plastic and the degradation of plastic into smaller particles.
Concerns have been raised about their incorporation into food
webs. Little is known about the fate and effects of nanoplastic,
especially for the freshwater environment. In this study, effects
of nano-polystyrene (nano-PS) on the growth and photosynthesis
of the green alga Scenedesmus obliquus and the growth,
mortality, neonate production, and malformations of the
zooplankter Daphnia magna were assessed. Nano-PS reduced
population growth and reduced chlorophyll concentrations in
the algae. Exposed Daphnia showed a reduced body size and
severe alterations in reproduction. Numbers and body size of
neonates were lower, while the number of neonate
malformations among neonates rose to 68% of the individuals. These effects of nano-PS were observed between 0.22 and
103 mg nano-PS/L. Malformations occurred from 30 mg of nano-PS/L onward. Such plastic concentrations are much higher
than presently reported for marine waters as well as freshwater, but may eventually occur in sediment pore waters. As far as we
know, these results are the first to show that direct life history shifts in algae and Daphnia populations may occur as a result of
exposure to nanoplastic.