Q Jiang1, F Xia1,2, T Zhu1, D Wang1, Z Quan1. 1. Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, School of Life Sciences, Fudan University, Shanghai, P.R. China. 2. School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, P.R. China.
Abstract
AIMS: To investigate the distribution of complete ammonia oxidizers (comammox) and canonical ammonia-oxidizing bacteria (AOB) in tidal flat sediments of the Yangtze River estuary at different depths over four seasons. METHODS AND RESULTS: A two-step PCR with highly degenerate primers (THDP-PCR), coupled with Illumina Miseq-based sequencing, was used to analyse the distribution of comammox and AOB in tidal flat sediments. The proportion of comammox compared with that of AOB was relatively high in spring. The intermediate sediments (1-5 cm) had higher proportions of comammox than those on the surface (0-1 cm) and lower sediments (5-10 cm). Diversity indices confirmed a higher diversity of comammox in the lower sediments (5-10 cm). The proportion of comammox clade A.1 was much higher than that of comammox clade A.2 in all seasons. Redundancy analysis demonstrated that comammox clade A.1 was negatively correlated with total carbon and ammonium concentrations, whereas the opposite was observed in AOB. CONCLUSIONS: Results revealed the specific distribution of comammox and AOB in tidal flat sediments of the Yangtze River estuary. SIGNIFICANCE AND IMPACT OF THE STUDY: This study will contribute to the understanding of nitrification by comammox and AOB in tidal flat sediments.
AIMS: To investigate the distribution of complete ammonia oxidizers (comammox) and canonical ammonia-oxidizing bacteria (AOB) in tidal flat sediments of the Yangtze River estuary at different depths over four seasons. METHODS AND RESULTS: A two-step PCR with highly degenerate primers (THDP-PCR), coupled with Illumina Miseq-based sequencing, was used to analyse the distribution of comammox and AOB in tidal flat sediments. The proportion of comammox compared with that of AOB was relatively high in spring. The intermediate sediments (1-5 cm) had higher proportions of comammox than those on the surface (0-1 cm) and lower sediments (5-10 cm). Diversity indices confirmed a higher diversity of comammox in the lower sediments (5-10 cm). The proportion of comammox clade A.1 was much higher than that of comammox clade A.2 in all seasons. Redundancy analysis demonstrated that comammox clade A.1 was negatively correlated with total carbon and ammonium concentrations, whereas the opposite was observed in AOB. CONCLUSIONS: Results revealed the specific distribution of comammox and AOB in tidal flat sediments of the Yangtze River estuary. SIGNIFICANCE AND IMPACT OF THE STUDY: This study will contribute to the understanding of nitrification by comammox and AOB in tidal flat sediments.