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Niche separation of comammox Nitrospira and canonical ammonia oxidizers in an acidic subtropical forest soil under long-term nitrogen deposition.
- Source :
-
Soil Biology & Biochemistry . Nov2018, Vol. 126, p114-122. 9p. - Publication Year :
- 2018
-
Abstract
- The recent discovery of comammox Nitrospira capable of converting ammonia to nitrate in a single organism radically challenged our century-long perception of the classic two-step nitrification performed by ammonia oxidizers and nitrite oxidizers. However, our understanding of the niche separation of comammox Nitrospira and canonical nitrifiers in forest ecosystems remains limited, especially under a global scenario of elevated nitrogen (N) deposition. Here we evaluated the impacts of six-year N deposition on the dynamics of comammox Nitrospira , ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in a subtropical forest soil. Soil inorganic N concentrations significantly increased under the six-year simulation of N deposition, while soil pH, available phosphorus, total carbon (C), C/N ratio and microbial biomass significantly decreased. Quantitative PCR showed that the amoA gene abundances of comammox Nitrospira clade B and AOA substantially increased under the increasing rates of N deposition. By contrast, the AOB amoA gene abundance significantly decreased with the higher levels of N deposition (100 and 150 kg N ha−1 yr−1). Increased 13CO 2 incorporation into the AOA communities, rather than comammox Nitrospira or AOB, was demonstrated in a DNA-stable isotope probing microcosm, indicative of the capacity of AOA to assimilate 13CO 2 through autotrophic nitrification in the investigated subtropical forest soil under long-term N deposition. Phylogenetic analysis revealed that the autotrophic AOA assemblages belonged to the Nitrosotalea cluster, and their capacity for assimilating CO 2 through autotrophic nitrification was not affected by the long-term N deposition. Taken together, we provided new evidence for the niche separation of comammox Nitrospira and canonical ammonia oxidizers in soil nitrification under the long-term N deposition in the acidic subtropical forest soil. Highlights • The abundances of comammox Nitrospira clade B and AOA increased with N input. • The abundance of AOB decreased with N input rates higher than 100 kg N ha−1 yr−1. • Increased 13CO 2 was only incorporated into soil AOA through autotrophic pathway. • N input showed no effect on autotrophic AOA within the Nitrosotalea cluster. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00380717
- Volume :
- 126
- Database :
- Academic Search Index
- Journal :
- Soil Biology & Biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 131901623
- Full Text :
- https://doi.org/10.1016/j.soilbio.2018.09.004