Seasonal Abundance and Community of Ammonia-oxidizing Bacteria in the Musi River Sediment, South Sumatra, Indonesia

Background and Objective: Human activities along the Musi river contribute to the waste inputs especially nitrogen which has a negative ecological impact. A micro-organism group that play a crucial role in the nitrogen cycle is Ammonia-Oxidizing Bacteria (AOB). Materials and Methods: In the present study, AOB community were analyzed during rainy and dry seasons based on PCR T-RFLP analysis of 16S rRNA and amoA genes. The amplified genes were digested with AluI, BsuRI and MspI. Results: Nitrosospira and Nitrosomonas from class $-proteobacteria were the dominant abundances based on 16S rRNA and amoA genes were found from freshwater to brackish water but Nitrosococcus from class -proteobacteria was found only in brackish water. The AOB communities based on 16S rRNA and amoA genes in dry season were higher than in rainy season. The salinity, temperature, DO and nutrients contributed to the AOB community. Salinity was the most dominant factor affected the AOB community. Conclusion: Variability in salinity caused the spatial distribution to the AOB in the Musi river.