Response of ammonia-oxidizing archaea and bacteria to streptomycin sulfate and penicillin in coastal wetlands along the Bohai Rim

Antibiotics are pollutants that are constantly discharged into ocean and coastal wetlands and affect the growth and activity of microorganisms. Ammonia-oxidizing archaea (AOA) and bacteria (AOB), which are very important in the global nitrogen cycle, are affected by antibiotics in the environment as well. Antibiotics have different influences on AOA and AOB microbial communities due to their different biochemical compositions and metabolic mechanisms, which change the ammonia-oxidizing process in different environments. In this study, 62 samples from four typical coastal wetland types along the Bohai Rim were collected and treated with streptomycin sulfate and penicillin in the laboratory. The total ammonia oxidation rate decreased by 61.2-84.0% with streptomycin sulfate and decreased by 50.0-74.5% with penicillin. The significant change in abundance and community structure indicated that AOB were more inhibited than AOA by streptomycin sulfate and penicillin. Nevertheless, ecological network analysis verified that the internal association in the AOA community was more fragile than that in the AOB community. Moreover, the relationship between AOA and other nitrogen-transforming functional archaea weakened in the presence of antibiotics, while AOB established relationships with more nitrogen-transforming functional bacteria in the presence of antibiotics. Streptomycin sulfate had a stronger effect than penicillin due to the different inhibiting mechanisms of these antibiotics and the promotion of interspecific cooperation induced by penicillin in AOA.