Soil nitrogen(N)transformation processes in the High Arctic tundra are poorly understood even though nitrogen is one of the main limiting nutrients.We analyzed soil samples collected along a High Arctic tundra transec...Soil nitrogen(N)transformation processes in the High Arctic tundra are poorly understood even though nitrogen is one of the main limiting nutrients.We analyzed soil samples collected along a High Arctic tundra transect to investigate spatial variability in key nitrogen transformation processes,functional gene abundances,ammonia-oxidizing archaea(AOA)community structures,and key nitrogen transformation regulators.The potential denitrification rates were higher than the nitrification rates in the soil samples,although nitrification may still regulate N2O emissions from tundra soil.The nutrient(total carbon,total organic carbon,total nitrogen,and NH_(4)^(+)-N)contents were important determinants of spatial variability in the potential denitrification rates of soil along the tundra transect.The total sulfurcontent was the main variable controlling potential nitrification processes,probably in association with sulfate-reducing bacteria.The nitrate content was the main variable affecting potential dissimilatory nitrate reduction to ammonium.AOA and ammonia-oxidizing bacteria amoA,nirS,and anammox 16S rRNA genes were found in all of the soil samples.AOA play more important roles than ammonia-oxidizing bacteria in soilnitrification.Anammox bacteria may utilize NO_(2)^(-)produced through nitrification.Phylogenetic analysis indicated that the AOA amoA sequences could be grouped into eight unique operational taxonomic units(OTUs)with a 97%sequence similarity and were affiliated with three group 1.1b Nitrososphaeraclusters.The results indicated that heterogeneous environmental factors(e.g.,the carbon and nitrogen contents of soil)along the High Arctic tundra transect strongly affected the nitrogen transformation rate and relevant functional gene abundances in soil.展开更多
为了增强精密整流电路实验的教学效果,设计一种基于NI ELVIS II+平台的综合实验项目和虚拟实验平台。该平台拥有硬件与软件组合成一体的、完整的教学实验室虚拟仪器套件,可以完成理论与实践、元件与系统、验证与分析等多角度相结合的综...为了增强精密整流电路实验的教学效果,设计一种基于NI ELVIS II+平台的综合实验项目和虚拟实验平台。该平台拥有硬件与软件组合成一体的、完整的教学实验室虚拟仪器套件,可以完成理论与实践、元件与系统、验证与分析等多角度相结合的综合性实验设计。该项目有助于增强学生自主学习的积极性,提高学生的实践创新能力,达到良好的教学效果。展开更多
基金This study was funded by the National Key Research and Development Program of China(Grant no.2020YFA0608501)the National Natural Science Foundation of China(Grant no.41976220)the State Key Laboratory of NBC Protection of Civilians(Grant no.SKLNBC2020-10).
文摘Soil nitrogen(N)transformation processes in the High Arctic tundra are poorly understood even though nitrogen is one of the main limiting nutrients.We analyzed soil samples collected along a High Arctic tundra transect to investigate spatial variability in key nitrogen transformation processes,functional gene abundances,ammonia-oxidizing archaea(AOA)community structures,and key nitrogen transformation regulators.The potential denitrification rates were higher than the nitrification rates in the soil samples,although nitrification may still regulate N2O emissions from tundra soil.The nutrient(total carbon,total organic carbon,total nitrogen,and NH_(4)^(+)-N)contents were important determinants of spatial variability in the potential denitrification rates of soil along the tundra transect.The total sulfurcontent was the main variable controlling potential nitrification processes,probably in association with sulfate-reducing bacteria.The nitrate content was the main variable affecting potential dissimilatory nitrate reduction to ammonium.AOA and ammonia-oxidizing bacteria amoA,nirS,and anammox 16S rRNA genes were found in all of the soil samples.AOA play more important roles than ammonia-oxidizing bacteria in soilnitrification.Anammox bacteria may utilize NO_(2)^(-)produced through nitrification.Phylogenetic analysis indicated that the AOA amoA sequences could be grouped into eight unique operational taxonomic units(OTUs)with a 97%sequence similarity and were affiliated with three group 1.1b Nitrososphaeraclusters.The results indicated that heterogeneous environmental factors(e.g.,the carbon and nitrogen contents of soil)along the High Arctic tundra transect strongly affected the nitrogen transformation rate and relevant functional gene abundances in soil.
文摘为了增强精密整流电路实验的教学效果,设计一种基于NI ELVIS II+平台的综合实验项目和虚拟实验平台。该平台拥有硬件与软件组合成一体的、完整的教学实验室虚拟仪器套件,可以完成理论与实践、元件与系统、验证与分析等多角度相结合的综合性实验设计。该项目有助于增强学生自主学习的积极性,提高学生的实践创新能力,达到良好的教学效果。
