Niche separation of comammox Nitrospira and canonical ammonia oxidizers in an acidic subtropical forest soil under long-term nitrogen deposition

Publication date: Available online 4 September 2018Source: Soil Biology and BiochemistryAuthor(s): Xiuzhen Shi, Hang-Wei Hu, Jianqing Wang, Ji-Zheng He, Chengyang Zheng, Xiaohua Wan, Zhiqun HuangAbstractThe 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 13CO2 incorporation into the AOA communities, rather than comammox Nitrospira or AOB, was demonstrated in a DNA-stable ...
Source: Soil Biology and Biochemistry - Category: Biology Source Type: research