As a newly discovered group of ammonia-oxidizing microorganisms, complete ammonia oxidizing (comammox) Nitrospira has been widely found in various oligotrophic ecosystems. However, their activity and ecological niche is still unclear in recirculating aquaculture systems (RAS). This study aimed to compare the abundance and activity of comammox Nitrospira, ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), and elucidate metabolic versatility of comammox Nitrospira in RAS. Quantitative PCR (qPCR) results showed that either comammox Nitrospira or AOB numerically predominated, while comammox Nitrospira and AOA shared similar low ammonia niches. Specifically, DNA-based stable isotope probing in conjunction with high-throughput 16S rRNA gene amplicon sequencing revealed that comammox Nitrospira accounted for 79.1 %, 97.5 %, 91.9 % and 97.6 % in the active ammonia-oxidizing community in four selected typical samples representing high abundance of comammox, AOA, and AOB, respectively. Phylogenetic analysis of heavy fraction DNA further identified novel comammox species from Nitrospira nitrificans cluster and clade A.2 acting as active species in different freshwater aquariums. Moreover, metagenome-assembled genome analysis revealed them as novel species with stress resistance and metabolic diversity compared with known comammox Nitrospira. This study underscores the dominant role of comammox Nitrospira as active ammonia-oxidizers in RAS and presents two novel comammox MAGs with metabolic flexibility, enriching our understanding of the nitrification process in oligotrophic artificial ecosystems.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.watres.2024.122949 | DOI Listing |
Bioresour Technol
December 2024
School of Environment, Guangdong Engineering Research Center of Water Treatment Processes and Materials, Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 510632, China.
Despite their widespread presence in acidic environments, the stability and adaptative mechanisms of complete ammonia oxidization (comammox) bacteria remain poorly understood. In this three-year study, comammox Nitrospira consistently dominated both abundance and activity in an acidic nitrifying reactor (pH = 6.3-6.
View Article and Find Full Text PDFWater Res
December 2024
College of Water Science, Beijing Normal University, Beijing 100875, PR China.
Ammonia oxidizers are key players in the biogeochemical nitrogen cycle. However, in critical ecological zones such as estuaries, especially those affected by widespread anthropogenic dam control, our understanding of their occurrence, ecological performance, and survival strategies remains elusive. Here, we sampled sediments along the Haihe River-Estuary continuum in China, controlled by the Haihe Tidal Gate, and employed a combination of biochemical and metagenomic approaches to investigate the abundance, activity, and composition of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), and complete ammonia oxidizers (comammox).
View Article and Find Full Text PDFWater Res
December 2024
State Key Laboratory of Estuarine and Coastal Research, East China Normal University, 500 Dongchuan Road, Shanghai 200241, PR China; Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographical Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, PR China.
Biofilms are indispensable ecological habitats for microbes that have garnered global attention and play a potential role in influencing the biogeochemical cycling of nitrogen. However, the biogeochemical significance of biofilms and the mechanisms by which they regulate nitrogen cycling remain elusive. In this study, we utilized DNA-stable isotope probing (DNA-SIP) labelling techniques in conjunction with metagenomics to reveal a nitrifying ecological niche in biofilms taken from the Yangtze Estuary, with those from sediment and water samples for comparison.
View Article and Find Full Text PDFWater Res
December 2024
Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia.
As a newly discovered group of ammonia-oxidizing microorganisms, complete ammonia oxidizing (comammox) Nitrospira has been widely found in various oligotrophic ecosystems. However, their activity and ecological niche is still unclear in recirculating aquaculture systems (RAS). This study aimed to compare the abundance and activity of comammox Nitrospira, ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), and elucidate metabolic versatility of comammox Nitrospira in RAS.
View Article and Find Full Text PDFEnviron Res
December 2024
Australian Centre for Water and Environmental Biotechnology (ACWEB, Formerly AWMC), The University of Queensland, St. Lucia, Queensland, 4072, Australia.
Ammonia oxidation, the first and rate-limiting step of nitrification, is a crucial step in nitrogen cycling. The distribution patterns of key ammonia oxidizers, including ammonia-oxidizing archaea (AOA) and bacteria (AOB), and comammox (complete ammonia oxidation) Nitrospira, provide vital insights for nitrogen cycling in natural ecosystems. Currently, the distribution and contribution of AOA, AOB and comammox Nitrospira in freshwater ecosystems remain largely underexplored.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!