Nitrogen(N) application may lead to niche segregation of soil ammonia-oxidizing archaea(AOA) and bacteria(AOB), thereby reducing the competitive interactions between AOA and AOB due to higher ammonium substrate availa...Nitrogen(N) application may lead to niche segregation of soil ammonia-oxidizing archaea(AOA) and bacteria(AOB), thereby reducing the competitive interactions between AOA and AOB due to higher ammonium substrate availability. However, the adaptive mechanisms of AOA and AOB under N enrichment remain poorly understood. Stable isotope probing(SIP) microcosm incubation was employed to reveal community changes of active AOA and AOB in a loess soil from a field experiment growing potatoes that received no N(control, CK), low N(LN, 75 kg N ha^(-1)), and high N(HN, 375 kg N ha^(-1)). The results showed that the soil potential nitrification rate(PNR) was measured by culturing of the soil samples from the field experiment. Soil PNR was significantly increased in HN by87.5% and 67.5% compared with CK and LN, respectively. Compared with CK, the^(13)C-amoA genes of soil AOA and AOB in HN had 2.58 × 10~4 and 1.55 × 10~6 copies, representing 1.6-and 16.2-fold increase respectively. It was indicated that AOB dominated soil ammonia oxidation. A phylogenetic analysis of the^(13)C-amoA gene showed that N application significantly increased the proportion of54 d9-like AOA up to 90% in HN, while the Nitrososphaera gargensis-like and Nitrososphaera viennensis-like AOA were inhibited and completely disappeared. Nitrogen application also resulted in the community shift of active AOB-dominant group from Nitrosospira briensis-like to Nitrosospira sp. TCH711-like. Our study provides compelling evidence for the emergence and maintenance of active nitrifying communities under the intensified N input to an agricultural ecosystem.展开更多
Heavy metal pollution affects soil ecological function.Biochar and compost can effectively remediate heavy metals and increase soil nutrients.The effects and mechanisms of biochar and compost amendments on soil nitrog...Heavy metal pollution affects soil ecological function.Biochar and compost can effectively remediate heavy metals and increase soil nutrients.The effects and mechanisms of biochar and compost amendments on soil nitrogen cycle function in heavy-metal contaminated soils are not fully understood.This study examined how biochar,compost,and their integrated use affected ammonia-oxidizing microorganisms in heavy metal polluted soil.Quantitative PCR was used to determine the abundance of ammonia-oxidizing archaea(AOA)and bacteria(AOB).Ammonia monooxygenase(AMO)activity was evaluated by the enzymelinked immunosorbent assay.Results showed that compost rather than biochar improved nitrogen conversion in soil.Biochar,compost,or their integrated application significantly reduced the effective Zn and Cd speciation.Adding compost obviously increased As and Cu effective speciation,bacterial 16 S rRNA abundance,and AMO activity.AOB,stimulated by compost addition,was significantly more abundant than AOA throughout remediation.Correlation analysis showed that AOB abundance positively correlated with NO_(3)^(-)-N(r=0.830,P<0.01),and that AMO activity had significant correlation with EC(r=-0.908,P<0.01)and water-soluble carbon(r=-0.868,P<0.01).Those seem to be the most vital factors affecting AOB community and their function in heavy metal-polluted soil remediated by biochar and compost.展开更多
Ammonia is important for industrial development and human life.The traditional Haber Bosch method converts nitrogen into ammonia gas at high temperatures and pressures,causing serious pollution and greenhouse gas emis...Ammonia is important for industrial development and human life.The traditional Haber Bosch method converts nitrogen into ammonia gas at high temperatures and pressures,causing serious pollution and greenhouse gas emissions.These problems prompt the nitrogen fixation method to proceed in a sustainable way.Ultrathin Ni/V-layered double hydroxides(Ni/V-LDHs)nanosheets with different proportions were prepared successfully for photocatalystic reduction of nitrogen to ammonia,through aqueous miscible organic solvent method(AMO)to achieve the higher surface area and rich oxygen vacancies,containing more carriers and active sites to enhance nitrogen reduction.And the optimal catalyst of Ni/V-LDHs 11 AMO possesses the highest photocatalytic efficiency(176μmol·g^(-1)·h^(-1)),indicating its potential application prospects in catalyst fields.Consequently,this work achieves an environmentally friendly,low-cost and efficient conversion method for nitrogen reduction to ammonia through solar energy.展开更多
基金supported by the National Key Basic Research Program of China (No. 2015CB150501)the National Natural Science Foundation of China (No. 41530857)
文摘Nitrogen(N) application may lead to niche segregation of soil ammonia-oxidizing archaea(AOA) and bacteria(AOB), thereby reducing the competitive interactions between AOA and AOB due to higher ammonium substrate availability. However, the adaptive mechanisms of AOA and AOB under N enrichment remain poorly understood. Stable isotope probing(SIP) microcosm incubation was employed to reveal community changes of active AOA and AOB in a loess soil from a field experiment growing potatoes that received no N(control, CK), low N(LN, 75 kg N ha^(-1)), and high N(HN, 375 kg N ha^(-1)). The results showed that the soil potential nitrification rate(PNR) was measured by culturing of the soil samples from the field experiment. Soil PNR was significantly increased in HN by87.5% and 67.5% compared with CK and LN, respectively. Compared with CK, the^(13)C-amoA genes of soil AOA and AOB in HN had 2.58 × 10~4 and 1.55 × 10~6 copies, representing 1.6-and 16.2-fold increase respectively. It was indicated that AOB dominated soil ammonia oxidation. A phylogenetic analysis of the^(13)C-amoA gene showed that N application significantly increased the proportion of54 d9-like AOA up to 90% in HN, while the Nitrososphaera gargensis-like and Nitrososphaera viennensis-like AOA were inhibited and completely disappeared. Nitrogen application also resulted in the community shift of active AOB-dominant group from Nitrosospira briensis-like to Nitrosospira sp. TCH711-like. Our study provides compelling evidence for the emergence and maintenance of active nitrifying communities under the intensified N input to an agricultural ecosystem.
基金supported by the Hunan Provincial Key Research and Development Project(Nos.2019WK2031 and 2017SK2351)the National Natural Science Foundation of China(No.51408219)+1 种基金the Natural Science Foundation of Hu-nan Province(No.2020JJ5259)the Outstanding Youth Fund Project of the Hunan Education Department(No.18B094)。
文摘Heavy metal pollution affects soil ecological function.Biochar and compost can effectively remediate heavy metals and increase soil nutrients.The effects and mechanisms of biochar and compost amendments on soil nitrogen cycle function in heavy-metal contaminated soils are not fully understood.This study examined how biochar,compost,and their integrated use affected ammonia-oxidizing microorganisms in heavy metal polluted soil.Quantitative PCR was used to determine the abundance of ammonia-oxidizing archaea(AOA)and bacteria(AOB).Ammonia monooxygenase(AMO)activity was evaluated by the enzymelinked immunosorbent assay.Results showed that compost rather than biochar improved nitrogen conversion in soil.Biochar,compost,or their integrated application significantly reduced the effective Zn and Cd speciation.Adding compost obviously increased As and Cu effective speciation,bacterial 16 S rRNA abundance,and AMO activity.AOB,stimulated by compost addition,was significantly more abundant than AOA throughout remediation.Correlation analysis showed that AOB abundance positively correlated with NO_(3)^(-)-N(r=0.830,P<0.01),and that AMO activity had significant correlation with EC(r=-0.908,P<0.01)and water-soluble carbon(r=-0.868,P<0.01).Those seem to be the most vital factors affecting AOB community and their function in heavy metal-polluted soil remediated by biochar and compost.
基金This work was financially supported by the National Basic Research Program of China(No.2014CB932101)the National Natural Science Foundation of China,111 Project(No.B07004)+1 种基金Program for Changjiang Scholars and Innovative Research Team in University(No.IRT1205)the Fundamental Research Funds for the Central Universities(No.buctrc201527).
文摘Ammonia is important for industrial development and human life.The traditional Haber Bosch method converts nitrogen into ammonia gas at high temperatures and pressures,causing serious pollution and greenhouse gas emissions.These problems prompt the nitrogen fixation method to proceed in a sustainable way.Ultrathin Ni/V-layered double hydroxides(Ni/V-LDHs)nanosheets with different proportions were prepared successfully for photocatalystic reduction of nitrogen to ammonia,through aqueous miscible organic solvent method(AMO)to achieve the higher surface area and rich oxygen vacancies,containing more carriers and active sites to enhance nitrogen reduction.And the optimal catalyst of Ni/V-LDHs 11 AMO possesses the highest photocatalytic efficiency(176μmol·g^(-1)·h^(-1)),indicating its potential application prospects in catalyst fields.Consequently,this work achieves an environmentally friendly,low-cost and efficient conversion method for nitrogen reduction to ammonia through solar energy.