Wide distribution of anaerobic ammonium‐oxidizing bacteria in the water column of the South China Sea: Implications for their survival strategies

Abstract

Aim Anammox bacteria are widely distributed in various environments, but the community composition and survival strategies of anammox bacteria in oligotrophic, deep‐sea water rich in dissolved oxygen (DO) remain unknown. We aimed to understand the distribution of anammox bacteria in the water columns of the South China Sea (SCS). Time period Three cruises were in October 2014, October 2015 and September 2016, respectively. Location Six water columns were obtained in the SCS, China (E 111–120°, N 16–22°). Methods The diversity and community composition of anammox bacteria were investigated through a high‐throughput sequencing technique targeting the anammox 16S rRNA gene. Results Unexpectedly, phylogenetic analysis showed that Ca. Brocadia (78.35%) was the dominant genus while Ca. Scalindua and unclassified species accounted for 12.62% and 9.03%, respectively. The highest diversity of anammox bacteria and concentrations of particulate organic matter (POM) were simultaneously observed in the 50–200 m layer, suggesting that particles may be a favourable niche for anammox bacteria. The wide distribution of anammox bacteria in the DO‐rich sea waters suggests two possible survival strategies: one strategy is attaching to particles and using anaerobic anammox metabolism to produce energy, and the other strategy is free‐living and using aerobic metabolism to produce energy. Main conclusions A high diversity of anammox bacteria was found in the aerobic water columns, and Ca. Brocadia was the clearly dominant genus. Furthermore, anammox microbes could improve their viability by switching their metabolic pathways between anaerobic and aerobic conditions. Overall, our study has improved the understanding of the distribution and survival strategies of anammox communities in an aerobic marine environment and could provide new ideas for engineering applications in wastewater treatment with anammox technology.

Recent advances in environmental DNA‐based biodiversity assessment and conservation

“…Based on high‐throughput sequencing and qPCR of anammox 16S rRNA gene, Liu et al. (2021) found diverse anammox bacteria in the aerobic water columns of the South China Sea, and Ca . Brocadia was the most dominant genus.…”

Ecological interactions and the underlying mechanism of anammox and denitrification across the anammox enrichment with eutrophic lake sediments

“…Although the roles of anammox in N removal during wastewater treatments were clearly clarified and widely used [ 10 ], much less is known about the underlying mechanism of anammox process in eutrophic lake ecosystems. So far, seven anammox genera (i.e., Candidatus Scalindua, Candidatus Brocadia, Candidatus Kuenenia, Candidatus Jettenia, Candidatus Anammoxoglobus, Candidatus Anammoximicrobium, and Candidatus Brasilis) affiliated to the phylum Planctomycetes have been identified [ 11 – 13 ]. Extensive analysis of the anammox gene sequences deposited in the public databases revealed distinct ecological niche differentiations of anammox bacteria in both natural and engineered ecosystems [ 14 ].…”

Novel Anammox Bacteria Discovered in the Untapped Subsurface Aquifers

“…Brocadiales in the phylum Planctomycetes. Anammox bacteria are widely distributed in diverse ecosystems and play critical roles in the nitrogen (N) cycle in oxygen-depleted habitats, such as marine oxygen minimum zones [11,12], marine sinking particles and sediments [13,14], wastewater treatment plants [15], wetland and agricultural soils [16,17]. Based on metagenomic sequencing, new and undescribed anammox bacteria were recently reported in subsurface ecosystems [18][19][20].…”