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| Effects of water table lowering and mowing on soil ammonia oxidizers and denitrifiers in alpine wetlands |
| Received:April 22, 2017 |
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| KeyWord:water table lowering;ammonia-oxidizing bacteria(AOB);ammonia-oxidizing archaea(AOA);denitrifiers;Zoige peatland |
| Author Name | Affiliation | E-mail | | SUN Yi-fei | State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
University of Chinese Academy of Sciences, Beijing 100049, China | | | SHEN Ju-pei | State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
University of Chinese Academy of Sciences, Beijing 100049, China | jpshen@rcees.ac.cn | | ZHANG Cui-jing | State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
University of Chinese Academy of Sciences, Beijing 100049, China | | | SUN Shu-cun | School of Life Sciences, Nanjing University, Nanjing 210023, China | | | HE Ji-zheng | State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
University of Chinese Academy of Sciences, Beijing 100049, China | |
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| Abstract: |
| Wetlands serve as the main sources and sinks of greenhouse gases. Understanding nitrogen cycling in wetlands would greatly help in the assessment of their response and feedback to global climate change. To investigate the effect of water table lowering and mowing on soil nitrification and denitrification in wetlands, a simulated water table lowering via digging drainage ditches at different depths and mowing experiment was set up in the Zoige peatland in the eastern Qinghai-Tibetan Plateau in 2013. The abundances of ammonia-oxidizing archaea, ammonia-oxidizing bacteria, and denitrifying groups were detected using a real-time PCR approach. Results based on the samples taken in July 2014 showed soil moisture decreased significantly with water table lowering. Both water table lowering and mowing significantly decreased soil heterotrophic respiration.The abundances of ammonia oxidizers and denitrifiers did not change under the treatments of water table lowering and mowing, whereas the ratio of abundance of AOA-amoA to AOB-amoA was significantly influenced by both mowing and interaction of mowing and water table lowering.Mowing significantly increased the relative abundance of the AOB-amoA gene but had no influence on that of the AOA-amoA gene, suggesting that the predominant role of AOB in ammonia oxidation.The abundance of nirS gene was higher than that of the nirK gene, indicating that the nirS gene was more sensitive to water table lowering and mowing. With the decline of water table, mowing promoted AOB-driven ammonia oxidation, while higher abundance of denitrifiers mitigated the accumulation of nitrate originated from ammonia oxidation, resulting in low soil nitrate content. |
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