The bacterial diversity and abundance in snow of the summit(8201 m) of Cho Oyu mountain,Tibet,were analyzed by 16S rRNA gene sequencing followed by scanning electronic microscopy analysis.Most of bacteria were found t...The bacterial diversity and abundance in snow of the summit(8201 m) of Cho Oyu mountain,Tibet,were analyzed by 16S rRNA gene sequencing followed by scanning electronic microscopy analysis.Most of bacteria were found to be of spherical or oval shape(>95%).Bacterial 16S rDNA sequences were classified into 5 genera(Caulobacter,Ralstonia,Cupriavidus,Pelomonas and Pseudomonas).Gammaproteobacteria were the most abundant(91.25%) among the library that consists of 594 clones.The sequences found in this study are highly similar to those previously retrieved from other cold en-vironments,such as ice core,sea ice,permafrost and snow.The results showed that the cold and barren environments strongly influence the survival of bacteria.The high similarity among sequences retrieved from snow sample and other places,such as ocean,soil and water,suggested that the bacteria in snow,soil and water environments have the same origin.展开更多
Characterized by obvious altitudinal variation,habitat complexity,and diversity in land cover,the Mt.Qomolangma region within the central Himalayas is one of the most sensitive areas to climate change in the world.At ...Characterized by obvious altitudinal variation,habitat complexity,and diversity in land cover,the Mt.Qomolangma region within the central Himalayas is one of the most sensitive areas to climate change in the world.At the same time,because the Mt.Qomolangma region possesses the most complete natural vertical spectrum in the world,it is also an ideal place to study the vertical structure of alpine land cover.In this study,land cover data for 2010 along with digital elevation model data were used to define three methods for dividing the northern and southern slopes in the Mt.Qomolangma region,i.e.,the ridgeline method,the sample transect method,and the sector method.The altitudinal distributions of different land cover types were then investigated for both the northern and southern slopes of the Mt.Qomolangma region by using the above three division methods along with ArcGIS and MATLAB tools.The results indicate that the land cover in the study region was characterized by obviously vertical zonation with the south-six and north-four pattern of vertical spectrum that reflected both the natural vertical structure of vegetation and the effects of human activities.From low to high elevation,the main land cover types were forests,grasslands,sparse vegetation,bare land,and glacler/snow cover.The compositions and distributions of land cover types differed significantly between the northern and southern slopes;the southern slope exhibited more complex land cover distributions with wider elevation ranges than the northern slope.The area proportion of each land cover type also varied with elevation.Accordingly,the vertical distribution patterns of different land cover types on the southern and northern slopes could be divided into four categories,with glaciers/snow cover,sparse vegetation,and grasslands conforming to unimodal distributions.The distribution of bare land followed a unimodal pattern on the southern slope but a bimodal pattern on the northern slope.Finally,the use of different slope division methods produced similar vertical belt structures on the southern slope but different ones on the northern slope.Among the three division methods,the sector method was better to reflect the natural distribution pattern of land cover.展开更多
基金the Knowledge Innovation Project of Chinese Academy of Sciences (Grant No.KSCX2-SW-331)
文摘The bacterial diversity and abundance in snow of the summit(8201 m) of Cho Oyu mountain,Tibet,were analyzed by 16S rRNA gene sequencing followed by scanning electronic microscopy analysis.Most of bacteria were found to be of spherical or oval shape(>95%).Bacterial 16S rDNA sequences were classified into 5 genera(Caulobacter,Ralstonia,Cupriavidus,Pelomonas and Pseudomonas).Gammaproteobacteria were the most abundant(91.25%) among the library that consists of 594 clones.The sequences found in this study are highly similar to those previously retrieved from other cold en-vironments,such as ice core,sea ice,permafrost and snow.The results showed that the cold and barren environments strongly influence the survival of bacteria.The high similarity among sequences retrieved from snow sample and other places,such as ocean,soil and water,suggested that the bacteria in snow,soil and water environments have the same origin.
基金National Natural Science Foundation of China.No.41761144081The Priority Research Program of Chinese Academy of Sciences,No.XDA20040201The Second Tibetan Plateau Scientific Expedition and Research,No.2019QZKK0603。
文摘Characterized by obvious altitudinal variation,habitat complexity,and diversity in land cover,the Mt.Qomolangma region within the central Himalayas is one of the most sensitive areas to climate change in the world.At the same time,because the Mt.Qomolangma region possesses the most complete natural vertical spectrum in the world,it is also an ideal place to study the vertical structure of alpine land cover.In this study,land cover data for 2010 along with digital elevation model data were used to define three methods for dividing the northern and southern slopes in the Mt.Qomolangma region,i.e.,the ridgeline method,the sample transect method,and the sector method.The altitudinal distributions of different land cover types were then investigated for both the northern and southern slopes of the Mt.Qomolangma region by using the above three division methods along with ArcGIS and MATLAB tools.The results indicate that the land cover in the study region was characterized by obviously vertical zonation with the south-six and north-four pattern of vertical spectrum that reflected both the natural vertical structure of vegetation and the effects of human activities.From low to high elevation,the main land cover types were forests,grasslands,sparse vegetation,bare land,and glacler/snow cover.The compositions and distributions of land cover types differed significantly between the northern and southern slopes;the southern slope exhibited more complex land cover distributions with wider elevation ranges than the northern slope.The area proportion of each land cover type also varied with elevation.Accordingly,the vertical distribution patterns of different land cover types on the southern and northern slopes could be divided into four categories,with glaciers/snow cover,sparse vegetation,and grasslands conforming to unimodal distributions.The distribution of bare land followed a unimodal pattern on the southern slope but a bimodal pattern on the northern slope.Finally,the use of different slope division methods produced similar vertical belt structures on the southern slope but different ones on the northern slope.Among the three division methods,the sector method was better to reflect the natural distribution pattern of land cover.
