Properties of ammonia‐oxidising bacteria and archaea in a hypereutrophic urban river network

Abstract

1. Ammonia oxidation by ammonia-oxidising archaea (AOA) and bacteria (AOB) is the first and rate-limiting step of nitrification. By providing substrate to the nitrogen-removing denitrification processes, nitrification is an important process for attenuation of allochthonous nitrogen loads in urban rivers, thereby mitigating eutrophication of downstream ecosystems. However, the relative importance of AOA and AOB communities in ammonia oxidation, the distribution and varied patterns of these groups and the underlying mechanisms have received limited study in hypereutrophic urban river networks.2. To investigate spatial and temporal patterns of particle-attached and free-living ammonia-oxidising microbial communities, we conducted a 2-year study of four different water quality/habitat conditions within a hypereutrophic urban river network of eastern China. The structure and dynamics of ammonia-oxidising microbial communities were determined by high-throughput sequencing based on the AOA and AOB amoA gene.3. We found significant spatial and temporal heterogeneity of ammonia-oxidising microbial communities, but no significant differences between particle-attached and free-living fractions. Analysis revealed that changes in the diversity and composition of ammonia-oxidising microbial communities were mainly related to substrate availability (e.g., ammonia, nitrite, dissolved oxygen). AOB communities were more complex and had a higher species richness and diversity compared with AOA communities. 4. Our findings indicate that high anthropogenic nitrogen loadings appear to promote higher ammonia-oxidising microbial richness and diversity, and AOB are more adaptable to the hypereutrophic conditions, thereby playing a more important role than AOA in nitrogen transformations in hypereutrophic urban river networks.5. This study highlights the importance of ammonia-oxidising microorganisms in nutrient-rich river systems and provides valuable insights into ammonia transport and transformations in urban river networks.

Partitional Clustering and Differential Abundance Analysis Reveal the Community Structure of eDNA in the Los Angeles River

“…The proposed nitrogen cycle for the soft bottom condition is shown Fgiure 7 Ammonia oxidizing archaea were represented by more species. This result partly disagrees with Cai et al's findings [76] since ammonia oxidizing archaea were more represented. However, some Nitrospira bacteria are complete ammonia oxidizers, so they may be equally important.…”

The Community Structure of eDNA in the Los Angeles River Reveals an Altered Nitrogen Cycle at Impervious Sites

“…Ammonia-oxidizing archaea were represented by more than one species. This result partly disagrees with the findings by Cai et al [87], since ammonia oxidizing archaea were more represented. However, some Nitrospira bacteria are complete ammonia oxidizers, so they may be equally important.…”

Urbanization alters the diversity, assembly and complexity in microbial generalist and specialist community of a subtropical river system

“…It gives a clear implication for the conservation of the specialists in order to mitigate the decline of river biodiversity in the face of rapid urbanization [130,131]. Moreover, identifying the relative importance of different taxa in maintaining the key ecological functions of urbanized river habitats and ecosystem stability is essential for the sustainable management of urbanized rivers [132].…”