Emerging investigator series: prompt response of estuarine denitrifying bacterial communities to copper nanoparticles at relevant environmental concentrations

The effects of metallic nanoparticles (NPs) on the estuarine biota have mostly been shown for concentrations higher than those actually measured or predicted in these environments. To address this gap, a range of concentrations expected to occur in estuarine environments (from 0.01 to 1 μg g −1 ) was employed in microcosms studies to assess the impact of Cu NPs in the denitrification pathway. This was achieved by quantifying the gene expression in estuarine sediments exposed to Cu NPs for up to six days and potential denitrification rates. The expression of nitrite ( nirS ) and nitrous oxide ( nosZ ) reductase genes was enhanced in a timewise manner upon exposure to Cu NPs