AME 56:13-23 (2009)  -  DOI: https://doi.org/10.3354/ame01313

Temporal variability in the abundance of ammonia-oxidizing bacteria vs. archaea in sandy sediments of the Douro River estuary, Portugal

Catarina M. Magalhães1,*, Ana Machado2, Adriano A. Bordalo1,2

1Centre of Marine and Environmental Research, Rua dos Bragas No. 289, 4050-123 Porto, Portugal
2Laboratory of Hydrobiology, Institute of Biomedical Sciences, University of Porto, Largo Prof. Abel Salazar No. 2, 4099-003 Porto, Portugal

ABSTRACT: We studied the relative abundance of betaproteobacterial ammonia-oxidizing bacteria (Betaproteobacteria AOB)  vs. ammonia-oxidizing archaea (AOA) in the intertidal sediments of the Douro estuary by quantifying Betaproteobacteria AOB and AOA amoA genes over 12 mo. We also evaluated the diversity of AOA in the sandy intertidal sediments of the estuary. Real-time PCR analysis showed that the abundance of Betaproteobacteria AOB amoA genes ranged from 0.8 × 106 to 7.5 × 106 copies cm–3 of sediment, corresponding to 0.8 to 8.4% of the total bacterial 16S rRNA gene copies, while that of AOA amoA genes ranged from 0.9 × 105 to 8.6 × 105 gene copies cm–3 of sediment, corresponding to 0.8 to 25.9% of the total archaeal copies. Results revealed that bacteria dominated the ammonia-oxidizing community almost over the entire survey period, with Betaproteobacteria AOB:AOA ratios ranging from 1 to 39. Nitrification activity estimations based on the numerical abundance of Betaproteobacteria AOB and AOA amoA, and comparison with measured nitrification rates indicated that Betaproteobacteria AOB were the major contributors to the nitrification process. Phylogenetic analysis of AOA revealed that archaeal amoA sequences retrieved from Douro estuarine sediments were closely related to sequences previously found in the water column, in soils and sediments.


KEY WORDS: Bacteria · Archaea · Ammonia-oxidation · Nitrification · Sandy sediments


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Cite this article as: Magalhães CM, Machado A, Bordalo AA (2009) Temporal variability in the abundance of ammonia-oxidizing bacteria vs. archaea in sandy sediments of the Douro River estuary, Portugal. Aquat Microb Ecol 56:13-23. https://doi.org/10.3354/ame01313

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