As shown in Table 2, the number of OTUs in the samples was 2,541–3,353, and the coverage was over 98% (coverage: 98–99%). It can be seen from the table that for the Shannon P₀ > P₉₆ > V₀ > V₉₆ and for the Simpson V₉₆ > V₀ > P₉₆ > P₀; thus, the bacterial diversity of the rhizosphere in the P. australis group was always higher than that in the V. natans group before degradation (0 h) and after degradation (96 h). In the above analysis of the degradation rate, that of the P. australis group was also greater than that of the V. natans group, which was consistent with the expression of diversity analysis. The main bacterial groups involved in SA degradation may be resistant to antibiotics, thus contributing to SA biodegradation (Yang et al. 2016).