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Ammonia-oxidizing beta-proteobacteria from the oxygen minimum zone off northern Chile
Verónica Molina1, Osvaldo Ulloa, Laura Farías
1Departamento de Oceanografía, Universidad de Concepción, PROFC-Cabina 7, Casilla 160-C, Concepción, Chile. vemolina@udec.cl
Applied and Environmental Microbiology
|April 10, 2007
Summary
Ammonia-oxidizing bacteria (betaAOB) composition was studied in oxygen-rich and oxygen-poor waters. A shift in ammonia monooxygenase (amoA) gene communities was observed along the oxygen gradient.
Area of Science:
- Marine microbiology
- Biogeochemistry
- Molecular ecology
Background:
- Ammonia-oxidizing bacteria (betaAOB) are crucial for nitrogen cycling in marine environments.
- Understanding betaAOB community structure and function is vital in diverse oceanic oxygen conditions.
Purpose of the Study:
- To investigate the composition of betaAOB in oxic and suboxic waters of the eastern South Pacific oxygen minimum zone (OMZ).
- To analyze the diversity of 16S rRNA and ammonia monooxygenase (amoA) genes to understand functional shifts.
Main Methods:
- Cloning and sequencing of 16S rRNA and amoA genes from water samples collected at various depths.
- Phylogenetic analysis of obtained gene sequences to determine bacterial affiliations.
Main Results:
- Nitrosospira-like cluster 1 dominated 16S rRNA gene libraries in both oxic and suboxic waters.
- A significant shift in amoA gene sequences was observed between oxic and suboxic OMZ waters.
- OMZ amoA sequences showed affiliation with cultured Nitrosospira spp. from clusters 0 and 2, and uncultured betaAOB from terrestrial/wastewater sources.
Conclusions:
- Nitrosospira-like betaAOB inhabit both oxic and suboxic waters associated with the OMZ.
- A clear community shift at the functional (amoA) level occurs along the oxygen gradient within the OMZ.
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