[Water Quality and Diversity of Denitrifier Community Structure of Typical Scenic Water Bodies in Xi'an].

Six micro-polluted landscape water bodies were selected to explore the relationship between water quality and the nirS-Type denitrifier community structure and diversity with an Illumina high-throughput sequencing technique. The results of a physico-chemical analysis of the water bodies showed that the Fengqing Park (FQ) and Laodong Park (LD) water bodies were classified as inferior Ⅴ water quality, the Qujiang Park (QJ), Mutasi Park (MTS), and Xinjiyuan Park (XJY) water bodies were classified as Ⅴ water quality, and the Yongyang Park (YY) water quality was classified as Ⅳ. The TN values varied from 1.21 mg·L-1 to 6.50 mg·L-1, with the lowest value found in YY and the highest in FQ (P<0.05). TP was significantly higher in LD (0.10 mg·L-1) and significantly lower in QJ[0.02 mg·L-1 (P<0.05)]. The NH4+-N in LD was 4.44 times higher than that in QJ and FQ (P<0.01). Illumina high-throughput sequencing revealed that the denitrifier community composition was significantly different among the six water bodies, and Paracoccus sp., Pseudomonas sp., and Rubrivivax sp. were the dominant genus species. A principle component analysis (PCA) indicated that the nirS-Type denitrifier communities of XJY and MTS were mainly regulated by NH4+-N and the permanganate index, LD and FQ were significantly influenced by NO3--N, NO2--N, TN, TP, and DO, and YY was significantly influenced by pH value. Our results showed that nirS-Type denitrifier communities were regulated by different water quality indicators.