Effects of CeO2 nanoparticles on the algal composition and photosynthetic activity of phototrophic biofilm

The influences of CeO2 nanoparticles (NPs) on phototrophic biofilm were explored in terms of the algal composition and photosynthetic activity. Biofilms were cultivated in an artificial flume and exposure experiments were conducted with two levels of CeO2 NPs (0.05 and 0.5 mg/L) for 10 days. Results showed that 0.05 mg/L CeO2 NPs treatment altered the algal composition of biofilms, while the total Chl a and the photosynthetic activity maintained at the similar level as the control test. 5 mg/L CeO2 NPs not only changed the algal composition of biofilms, but also significantly decreased the photosynthetic activity, suggesting that high concentration of CeO2 NPs might lead to serious consequences to the primary production and nutrient cycling in aquatic environments