Wetlands are vital ecosystems that perform essential functions such as climate regulation,environmental purification,material circulation and energy flow.They play an essential role in global biogeochemical cycles,dri...Wetlands are vital ecosystems that perform essential functions such as climate regulation,environmental purification,material circulation and energy flow.They play an essential role in global biogeochemical cycles,driven primarily by microorganisms.Understanding the distribution of wetland microorganisms across different temperature zones is key to comprehending their ecological roles.A meta-analysis of 704 wetland soil samples on microbial communities was conducted,using statistical methods like analysis of variance,principal component analysis,non-metric nultidimensional scaling,and structural equation modeling to examine biogeography and diversity across temperature zones.Our findings revealed a clear latitudinal diversity gradient pattern,with the highest microbial abundance in the tropics and the lowest in the southern temperate zone,which differed significantly from other temperature zones.Proteobacteria(37.76%-51.04%),Acidobacteria(5.11%-30.70%)and Bacteroidetes(3.43%-16.16%)dominanted the bacterial communities.Notably,the southern temperate zone showed significant variations,with a higher prevalence of Acidobacteria(30.07%).To investigate the causes of this variability,we screened 177 core microbiome and identified latitude as the core environmental factor influencing microbial community composition.Moreover,soil microorganisms exhibited strong nitrogen cycling potentials(particularly nirD and nirB)and carbon cycling potentials(especially accA),with gene abundances showing little variation across temperature zones.Wetland bacterial communities also demonstrated high stability,with average variation degree index values ranging from 0.1 to 0.3.Our results improve the understanding of the diversity and biogeographic mechanisms of wetland bacterial communities and hold significant implications for the management and conservation of wetlands.展开更多
Temperature plays a crucial role in shaping microbial ecosystems during anaerobic digestion.However,the specific microbial communities and their functions across a wide temperature range still remain elusive.This stud...Temperature plays a crucial role in shaping microbial ecosystems during anaerobic digestion.However,the specific microbial communities and their functions across a wide temperature range still remain elusive.This study employed a genome-centric metagenomic approach to explore microbial metabolic pathways and synergistic networks at temperatures of 35,44,53,55,and 65℃.A total of 84 metagenome assembled genomes(MAGs)were assembled,with over 65%of these MAGs corresponding to novel bacterial and archaeal species(including Firmicutes,Chloroflexota,Bacteroidia and Methanobacteriota),greatly enhancing our current comprehension anaerobic digestion process.Notably,functional annotation identified that 44_bin.2(Methanothrix_A sp.001602645)harbors enzymes associated with hydrogenotrophic metabolism.Additionally,this microorganism exhibited diverse metabolic capabilities at 44℃,a temperature commonly employed in industrial practice yet less explored in bench studies.Consequently,it implies a promising potential for conducting anaerobic digestion at a moderate thermophilic temperature,as opposed to the conventional mesophilic range.The microorganism exhibited a variety of metabolic capabilities at 44℃,a temperature frequently employed in industrial applications but underexplored in laboratory investigations.The findings suggest that anaerobic digestion carried out at moderate thermophilic temperatures may have a higher potential for methane production.展开更多
晴空颠簸是影响飞机安全运行和旅客旅行舒适度的重要恶劣天气之一。为了研究2017年6月6日02:10(协调世界时)发生在山西省长治市上空的一次强烈的晴空颠簸事件的产生机制,本文使用常规观测资料、NOAA-15和NOAA-18卫星辐射资料并通过天气...晴空颠簸是影响飞机安全运行和旅客旅行舒适度的重要恶劣天气之一。为了研究2017年6月6日02:10(协调世界时)发生在山西省长治市上空的一次强烈的晴空颠簸事件的产生机制,本文使用常规观测资料、NOAA-15和NOAA-18卫星辐射资料并通过天气学分析和中尺度WRF数值模式以及GSI(Grid point Statistical Interpolation)同化系统同化等方法,对此次事件开展了数值模拟和机理研究。结果表明:该次飞机颠簸事件是一个典型的高空急流—锋区耦合系统导致的晴空湍流所致,高空急流是导致晴空湍流的主要因素之一。导致该次晴空湍流事件发生的是大气一系列要素对冷空气入侵的响应。高空冷云(冷空气)发展南下是促进此次强颠簸事件发生的重要诱因。由于高空冷云的南下,使得长治上空温度经向梯度增加,而长治上空温度经向梯度增加,使得中纬度风切变增大,增大的水平风垂直切变,导致理查森数(Ri)数值变小,而较小的Ri值是产生KH(Kelvin-Helmholtz)不稳定的必要条件,由于K-H不稳定导致了长治上空出现晴空湍流。此外,中尺度WRF模式以及GSI同化系统能够较好地模拟颠簸区附近的大气温度场特征,表明文中的数值预报流程对于大气温度、风场以及晴空湍流的发展具有一定的预报能力。展开更多
当系统存在温度梯度时,液体中的纳米颗粒通常会沿着温度梯度的反方向,从高温端向低温端定向移动。但是在特定条件下,会出现颗粒从低温端向高温端移动的反向热泳现象。对于液体中碳纳米管颗粒而言,碳纳米管独特的物理性质使其在液体中的...当系统存在温度梯度时,液体中的纳米颗粒通常会沿着温度梯度的反方向,从高温端向低温端定向移动。但是在特定条件下,会出现颗粒从低温端向高温端移动的反向热泳现象。对于液体中碳纳米管颗粒而言,碳纳米管独特的物理性质使其在液体中的热泳特性变得更加复杂,其热泳及反向热泳机制尚不明确。本文基于分子动力学模拟方法,研究了液体中碳纳米管的热泳方向转变特性。基于平均力势(Potential Mean Force,PMF)方法的计算结果表明,当耦合系数较大时,PMF<0,温度梯度起主导作用,表现为正向热泳;当耦合系数较小时,PMF>0,密度梯度成为主要驱动力,表现为反向热泳。本文揭示了碳纳米管在液体中的热泳及反向热泳微观机制,阐明了温度梯度与密度梯度共同作用下碳纳米管热泳方向和大小的变化规律。展开更多
基金supported by the National Natural Science Foundation of China(No.52070019).
文摘Wetlands are vital ecosystems that perform essential functions such as climate regulation,environmental purification,material circulation and energy flow.They play an essential role in global biogeochemical cycles,driven primarily by microorganisms.Understanding the distribution of wetland microorganisms across different temperature zones is key to comprehending their ecological roles.A meta-analysis of 704 wetland soil samples on microbial communities was conducted,using statistical methods like analysis of variance,principal component analysis,non-metric nultidimensional scaling,and structural equation modeling to examine biogeography and diversity across temperature zones.Our findings revealed a clear latitudinal diversity gradient pattern,with the highest microbial abundance in the tropics and the lowest in the southern temperate zone,which differed significantly from other temperature zones.Proteobacteria(37.76%-51.04%),Acidobacteria(5.11%-30.70%)and Bacteroidetes(3.43%-16.16%)dominanted the bacterial communities.Notably,the southern temperate zone showed significant variations,with a higher prevalence of Acidobacteria(30.07%).To investigate the causes of this variability,we screened 177 core microbiome and identified latitude as the core environmental factor influencing microbial community composition.Moreover,soil microorganisms exhibited strong nitrogen cycling potentials(particularly nirD and nirB)and carbon cycling potentials(especially accA),with gene abundances showing little variation across temperature zones.Wetland bacterial communities also demonstrated high stability,with average variation degree index values ranging from 0.1 to 0.3.Our results improve the understanding of the diversity and biogeographic mechanisms of wetland bacterial communities and hold significant implications for the management and conservation of wetlands.
基金supported by the National Natural Science Foundation of China(No.52270138)。
文摘Temperature plays a crucial role in shaping microbial ecosystems during anaerobic digestion.However,the specific microbial communities and their functions across a wide temperature range still remain elusive.This study employed a genome-centric metagenomic approach to explore microbial metabolic pathways and synergistic networks at temperatures of 35,44,53,55,and 65℃.A total of 84 metagenome assembled genomes(MAGs)were assembled,with over 65%of these MAGs corresponding to novel bacterial and archaeal species(including Firmicutes,Chloroflexota,Bacteroidia and Methanobacteriota),greatly enhancing our current comprehension anaerobic digestion process.Notably,functional annotation identified that 44_bin.2(Methanothrix_A sp.001602645)harbors enzymes associated with hydrogenotrophic metabolism.Additionally,this microorganism exhibited diverse metabolic capabilities at 44℃,a temperature commonly employed in industrial practice yet less explored in bench studies.Consequently,it implies a promising potential for conducting anaerobic digestion at a moderate thermophilic temperature,as opposed to the conventional mesophilic range.The microorganism exhibited a variety of metabolic capabilities at 44℃,a temperature frequently employed in industrial applications but underexplored in laboratory investigations.The findings suggest that anaerobic digestion carried out at moderate thermophilic temperatures may have a higher potential for methane production.
文摘晴空颠簸是影响飞机安全运行和旅客旅行舒适度的重要恶劣天气之一。为了研究2017年6月6日02:10(协调世界时)发生在山西省长治市上空的一次强烈的晴空颠簸事件的产生机制,本文使用常规观测资料、NOAA-15和NOAA-18卫星辐射资料并通过天气学分析和中尺度WRF数值模式以及GSI(Grid point Statistical Interpolation)同化系统同化等方法,对此次事件开展了数值模拟和机理研究。结果表明:该次飞机颠簸事件是一个典型的高空急流—锋区耦合系统导致的晴空湍流所致,高空急流是导致晴空湍流的主要因素之一。导致该次晴空湍流事件发生的是大气一系列要素对冷空气入侵的响应。高空冷云(冷空气)发展南下是促进此次强颠簸事件发生的重要诱因。由于高空冷云的南下,使得长治上空温度经向梯度增加,而长治上空温度经向梯度增加,使得中纬度风切变增大,增大的水平风垂直切变,导致理查森数(Ri)数值变小,而较小的Ri值是产生KH(Kelvin-Helmholtz)不稳定的必要条件,由于K-H不稳定导致了长治上空出现晴空湍流。此外,中尺度WRF模式以及GSI同化系统能够较好地模拟颠簸区附近的大气温度场特征,表明文中的数值预报流程对于大气温度、风场以及晴空湍流的发展具有一定的预报能力。
文摘当系统存在温度梯度时,液体中的纳米颗粒通常会沿着温度梯度的反方向,从高温端向低温端定向移动。但是在特定条件下,会出现颗粒从低温端向高温端移动的反向热泳现象。对于液体中碳纳米管颗粒而言,碳纳米管独特的物理性质使其在液体中的热泳特性变得更加复杂,其热泳及反向热泳机制尚不明确。本文基于分子动力学模拟方法,研究了液体中碳纳米管的热泳方向转变特性。基于平均力势(Potential Mean Force,PMF)方法的计算结果表明,当耦合系数较大时,PMF<0,温度梯度起主导作用,表现为正向热泳;当耦合系数较小时,PMF>0,密度梯度成为主要驱动力,表现为反向热泳。本文揭示了碳纳米管在液体中的热泳及反向热泳微观机制,阐明了温度梯度与密度梯度共同作用下碳纳米管热泳方向和大小的变化规律。
