Evaluating the net effect of sulfadimidine on nitrogen removal in an aquatic microcosm environment

Abstract Antibiotics enter into aquatic pond sediments by wastewater and could make detrimental effects on microbial communities. In this study, we examined the effects of sulfadimidine on nitrogen removal when added to experimental pond sediments. We found that sulfadimidine increased the number of sulfadimidine resistant bacteria and significantly increased the abundance of sul2 at the end of the incubation time (ANOVA test at Tukey HSD, P  2 O reduction rate as well as the amount of nitrate reduction. Pearson correlation analysis revealed that the N 2 O reduction rate was significantly and negatively correlated with narG (r = −0.679, P  narG (r = 0.609, P  nirK (r = 0.611, P  Actinobacteria , Euryarchaeota , Gemmatimonadetes , Nitrospirae , Burkholderiaceae (a family of Proteobacteria ), and Thermoanaerobaculaceae (a family of Firmicutes ) decreased with sulfadimidine exposure. In sediments, Actinobacteria , Bacteroidetes , Cyanobacteria , Epsilonbacteraeota , Euryarchaeota , Firmicutes , Gemmatimonadetes , and Spirochaetes at may play key roles in nitrogen transformation. Overall, the study exhibited a net effect of antibiotic exposure regarding nitrogen removal in an aquatic microcosm environment through a combination of biochemical pathways and molecular pathways, and draws attention to controlling antibiotic pollution in aquatic ecosystems.