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Archaea predominate among ammonia-oxidizing prokaryotes in soils
S Leininger1, T Urich, M Schloter
1Department of Biology, University of Bergen, Jahnebakken 5, N-5020 Bergen, Norway.
Nature
|August 18, 2006
Summary
Archaeal ammonia oxidizers are significantly more abundant in soils than bacterial ones, playing a crucial role in the nitrogen cycle. This finding highlights their dominance in soil ecosystems and ammonia oxidation processes.
Area of Science:
- Microbiology
- Environmental Science
- Biogeochemistry
Background:
- Ammonia oxidation initiates nitrification, a vital process in the global nitrogen cycle.
- Nitrate availability impacts plant nutrition and can lead to groundwater pollution through leaching.
Purpose of the Study:
- To investigate the abundance of archaeal ammonia oxidizers in soil ecosystems.
- To compare the abundance of archaeal ammonia oxidizers with their bacterial counterparts.
Main Methods:
- Investigated the abundance of the ammonia monooxygenase (amoA) gene in 12 soils.
- Utilized Crenarchaeota-specific lipids (e.g., crenarchaeol) as biomarkers.
- Employed reverse transcription quantitative PCR and pyrosequencing for activity and abundance analysis.
Main Results:
- Archaeal amoA gene copies were up to 3,000-fold more abundant than bacterial amoA genes.
- Abundance of archaeal amoA genes correlated with crenarchaeota-specific lipids.
- Demonstrated in situ activity of archaea, confirming their numerical dominance.
Conclusions:
- Archaeal ammonia oxidizers are numerically dominant in soil ecosystems.
- Crenarchaeota are likely the primary ammonia-oxidizing organisms in terrestrial environments.
- This has significant implications for understanding the nitrogen cycle and soil microbial ecology.
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