In order to understand the relationship be- tween the community structure of bacteria in ice core and the past climate and environment, we initiated the study on the microorganisms in the three selected ice samples fr...In order to understand the relationship be- tween the community structure of bacteria in ice core and the past climate and environment, we initiated the study on the microorganisms in the three selected ice samples from the Malan ice core drilled from the Tibetan Plateau. The 16S ribosomal DNA (rDNA) molecules were directly amplified from the melt water samples, and three 16S rDNA clone li- braries were established. Among 94 positive clones, eleven clones with unique restriction pattern were used for partial sequence and compared with eight reported sequences from the same ice core. The phylotypes were divided into 5 groups: alpha, beta, gamma proteobacteria; CFB, and other eubac- teria group. Among them, there were many “typical Malan glacial bacteria” pertaining to psychrophilies and new bacte- ria found in the ice core. At a longer time scale, the concen- tration distribution of “typical Malan glacial bacteria” with depth showed negative correlation with temperature varia- tions and was coincident with dirty layer. It implied the in- fluence of temperature on the microbial record through im- pact on the concentrations of the “typical Malan glacial bac- teria”. In addition, the nutrition contained in ice was another important factor controlling the distribution of microbial population in ice core section. Moreover, the result displayed an apparent layer distribution of bacterial community in the ice core section, which reflected the microbial response to the past climatic and environmental conditions at the time of deposition.展开更多
Formate and acetate concentrations are meas- ured in a 22.56 m-depth ice core recovered in Mt. Muztagata Glacier, northwest Tibetan Plateau. The mean concentrations for formate and acetate in this ice core are 186.6&#...Formate and acetate concentrations are meas- ured in a 22.56 m-depth ice core recovered in Mt. Muztagata Glacier, northwest Tibetan Plateau. The mean concentrations for formate and acetate in this ice core are 186.6±160.1 and 136.4±133.9 ng/g, respectively. Study shows that there is a positive correlation between formate and nitrate, suggesting both continental origins. However, no significant relationship has been found between formate and acetate, though they both have obvious periodical variations. Because Mt. Muz- tagata lies in the mid-latitude and is correlative to the nearby human activities, formate and acetate concentrations are higher than those in Greenland and Antarctica. During re- cent decades, the increase of formate concentration in the Muztagata ice core and formaldehyde production shows a close correlation. We preliminarily presume that the high formate concentration in the Muztagata ice core is concerned with the thriving of house decoration in which excess for- maldehyde was used.展开更多
文摘In order to understand the relationship be- tween the community structure of bacteria in ice core and the past climate and environment, we initiated the study on the microorganisms in the three selected ice samples from the Malan ice core drilled from the Tibetan Plateau. The 16S ribosomal DNA (rDNA) molecules were directly amplified from the melt water samples, and three 16S rDNA clone li- braries were established. Among 94 positive clones, eleven clones with unique restriction pattern were used for partial sequence and compared with eight reported sequences from the same ice core. The phylotypes were divided into 5 groups: alpha, beta, gamma proteobacteria; CFB, and other eubac- teria group. Among them, there were many “typical Malan glacial bacteria” pertaining to psychrophilies and new bacte- ria found in the ice core. At a longer time scale, the concen- tration distribution of “typical Malan glacial bacteria” with depth showed negative correlation with temperature varia- tions and was coincident with dirty layer. It implied the in- fluence of temperature on the microbial record through im- pact on the concentrations of the “typical Malan glacial bac- teria”. In addition, the nutrition contained in ice was another important factor controlling the distribution of microbial population in ice core section. Moreover, the result displayed an apparent layer distribution of bacterial community in the ice core section, which reflected the microbial response to the past climatic and environmental conditions at the time of deposition.
文摘Formate and acetate concentrations are meas- ured in a 22.56 m-depth ice core recovered in Mt. Muztagata Glacier, northwest Tibetan Plateau. The mean concentrations for formate and acetate in this ice core are 186.6±160.1 and 136.4±133.9 ng/g, respectively. Study shows that there is a positive correlation between formate and nitrate, suggesting both continental origins. However, no significant relationship has been found between formate and acetate, though they both have obvious periodical variations. Because Mt. Muz- tagata lies in the mid-latitude and is correlative to the nearby human activities, formate and acetate concentrations are higher than those in Greenland and Antarctica. During re- cent decades, the increase of formate concentration in the Muztagata ice core and formaldehyde production shows a close correlation. We preliminarily presume that the high formate concentration in the Muztagata ice core is concerned with the thriving of house decoration in which excess for- maldehyde was used.
