昆侖山埡口深層多年凍土微生物多樣性及構建機制研究
發(fā)布時間：2018-11-17 19:53
【摘要】：多年凍土(permafrost)是地球上陸地冰凍圈的重要組成部分并且代表了一個關鍵的有機碳庫。微生物,包括細菌、古菌、光養(yǎng)性的藍細菌和綠藻、真菌以及原生動物,構成了多年凍土中主要的生物量與物種多樣性,并影響著多個重要的生物地球化學過程。近幾十年來,全球氣候變暖對多年凍土環(huán)境的影響備受關注,多年凍土融化以及微生物降解土壤有機質所導致的溫室氣體(二氧化碳、甲烷和一氧化二氮)釋放被認為是陸地生態(tài)系統(tǒng)向全球大氣系統(tǒng)反饋的主要途徑之一。確定凍土微生物群落的組成并理解它們的功能角色以及其如何響應氣候變化和多年凍土融化,是生態(tài)學家當前關注的熱點問題。青藏高原是獨特而脆弱的生態(tài)系統(tǒng),該地區(qū)分布的低緯度、高海拔多年凍土對于氣候變化尤為敏感。然而,與兩極地區(qū)相比,青藏高原凍土微生物研究相對薄弱,難以為世界上其他地區(qū)開展的凍土微生物研究以及該地區(qū)其他學科的研究提供科學依據和數據參考。本文以取自青藏高原腹地昆侖山埡口盆地的凍土樣品為材料,研究了凍土微生物(細菌、古菌和真菌)的生理生化特性、多樣性與群落結構,探討了凍土微生物群落的空間分布格局及生態(tài)驅動機制。主要結果摘要如下:(1)青藏高原昆侖山埡口多年凍土中微生物總數介于108~109個/克之間,可培養(yǎng)細菌數量為103~106 CFU/克土壤(干重);系統(tǒng)發(fā)育分析表明可培養(yǎng)細菌多樣性很高且隸屬于放線菌門(Actinobacteria)、厚壁菌門(Firmicutes)、變形菌門(Proteobacteria)、擬桿菌門(Bacteroidetes)和異常球菌-棲熱菌門(Deinococcus-Thermus)5個類群的44個屬,其中優(yōu)勢屬為節(jié)桿菌屬(Arthrobacter)、嗜冷桿菌屬(Psychrobacter)、動性球菌屬(Planococcus)、芽孢桿菌屬(Bacillus)及細桿菌屬(Microbacterium);生理生化特性研究表明分離的細菌菌株大多為耐冷菌,少數則具有嗜冷和嗜溫特征,并且93.6%和49.0%的菌株分別具有耐堿和耐鹽能力�？膳囵B(yǎng)真菌數量很低,介于0~103 CFU/克土壤(干重)之間,其隸屬于子囊菌門(Ascomycota)和擔子菌門(Basidiomycota)的5個屬:地絲霉屬(Geomyces)、枝孢霉屬(Cladosporium)、鏈格孢屬(Alternaria)、紅酵母屬(Rhodotorula)與隱球酵母屬(Cryptococcus)。(2)從青藏高原昆侖山埡口凍土中共發(fā)現(xiàn)62個真菌分子種,包括25個新種;真菌群落隸屬于子囊菌門、擔子菌門和毛霉亞門(Mucoromycotina)3個類群的10個綱,其中座囊菌綱(Dothideomycetes)的多樣性和相對豐度均最高;一些真菌類群廣泛存在于世界各地的多年凍土環(huán)境中,可能代表了世界廣布的嗜冷或耐冷真菌;真菌群落組成隨著深度變化,且在活動層和永凍層間差異顯著,土壤電導率是影響真菌群落組成的重要因子。(3)在青藏高原昆侖山埡口凍土巖芯中,共檢測出191個細菌分子種,隸屬于14門、52目,其中包括19個新目和108個新種,且變形菌門為優(yōu)勢類群;細菌群落的α多樣性隨深度增加而降低,且活動層樣品中多樣性高于永凍層;細菌群落同樣隨深度變化,且相對于永凍層,活動層樣品中群落組成差異更大;多種測量的土壤理化因子影響了細菌群落組成,其中土壤碳氮比和有機碳含量的影響尤為顯著。(4)相比于細菌,古菌群落的多樣性很低,共檢測到17個分子種,隸屬于奇古菌門(Thaumarchaeota)與廣古菌門(Euryarchaeota)的3個綱:Group I.1a、Group I.1b和熱原體綱(Thermoplasmata),其中包括1個新目和13個新種;高達99%的古菌克隆與三個已知的氨氧化古菌(Ammonia-oxidizing archaea,AOA)Candidatus Nitrosoarchaeum limnia、Candidatus Nitrososphaera gargensis和Nitrososphaera viennensis親緣關系密切;該結果暗示了氨氧化古菌在該地區(qū)多年凍土生態(tài)系統(tǒng)的碳氮循環(huán)過程中扮演著關鍵角色。(5)為了闡明細菌群落垂直分布的驅動機制,本文從生態(tài)和進化的角度進一步分析了細菌群落的空間變化及譜系格局。物種和譜系beta多樣性分析顯示,沿著凍土巖芯剖面,細菌群落并不是隨機的分布,而是顯示了距離衰減的分布格局;在5個采樣深度中,細菌群落的譜系結構是隨機的,然而所有群落顯示了平均的趨勢朝著譜系聚集;這些結果表明驅動細菌群落垂直分布的生態(tài)學過程主要是確定性的生態(tài)選擇,然而隨機性過程同樣發(fā)揮著作用。
[Abstract]:Permafrost is an important part of the earth's land freeze and represents a key organic carbon reservoir. The microorganisms, including bacteria, archaea, phototrophic cyanobacteria and green algae, fungi and protozoa, constitute the main biomass and species diversity in the permafrost, and affect many important biogeochemical processes. In recent decades, the effects of global warming on the permafrost environment have been of great concern, and the permafrost and the greenhouse gases (carbon dioxide, The release of methane and nitrous oxide) is considered one of the main ways to feed the terrestrial ecosystem to the global atmospheric system. It is a hot issue for ecologists to determine the composition of the frozen soil microbial community and understand their functional roles and how they respond to climate change and permafrost. The Qinghai-Tibet Plateau is a unique and fragile ecosystem. The low-latitude and high-altitude permafrost in the region is particularly sensitive to climate change. However, compared with the two-pole region, the research on the micro-organism of the frozen soil in the Qinghai-Tibet Plateau is relatively weak, and it is difficult to provide scientific basis and data reference for the research of the frozen soil microorganisms in other parts of the world and the research of other disciplines in the region. In this paper, the physiological and biochemical characteristics, diversity and community structure of the frozen soil microorganisms (bacteria, archaea and fungi) were studied, and the spatial distribution pattern and the ecological driving mechanism of the frozen soil microbial community were discussed. The main results are as follows: (1) The total number of microorganisms in the permafrost of the Kunlun Mountains in the Qinghai-Tibet Plateau is between 108 and 109/ g, and the number of bacteria can be 103-106 CFU/ g of soil (dry weight); the phylogenetic analysis shows that the bacterial diversity is high and belongs to the actinomycete. A total of 44 genera of 5 taxa of the 5 groups of the genus Firmicin, Proteobacteria, Bacteroides, and Deinococcus-Therus, the dominant species are Arthrobacter, Psychrobacter, and Planococcus, The results of the physiological and biochemical characteristics of Bacillus and Microbacterium showed that the isolated bacterial strains were mostly cold resistant bacteria, and a few were cold and warm, and 93.6% and 49. 0% of the strains had the ability of alkali and salt tolerance, respectively. The number of cultivable fungi is very low, between 0 and 103 CFU/ g of soil (dry weight), belonging to 5 genera of Ascomyota and Baidota, which belong to the genus Geotrichum, Cladosporium, Alternaria, Rhodotorula and Cryptococcus. (2) 62 fungal species, including 25 new species, were found in the frozen soil of the Kunlun Mountains in the Qinghai-Tibet Plateau, including 25 new species, and the fungal community was attached to 10 classes of 3 groups of the Ascomycetes, Basidiomycetes and Mucor, with the highest diversity and relative abundance; Some of the fungus groups are widely present in the permafrost environment around the world, which may represent the cold or cold-resistant fungi in the world. The composition of the fungus community varies with the depth, and the difference between the active layer and the permanent freezing layer is significant, and the soil conductivity is an important factor affecting the composition of the fungus community. (3) A total of 191 species of bacterial species, including 19 new species and 108 new species, were detected in the frozen soil core of the Kunlun Mountain in the Qinghai-Tibet Plateau, and there were 19 new species and 108 new species. The diversity of the bacterial community decreased with the increase of the depth. in that active lay sample, the diversity is higher than that of the permanent freezing layer; the bacterial community also changes with the depth, and the composition difference of the community in the sample of the active layer is greater with respect to the permanent freezing layer; and the soil physical and chemical factors of the various measurement influence the composition of the bacterial community, in which the effect of the carbon-to-nitrogen ratio and the organic carbon content of the soil is particularly significant. (4) As compared with the bacteria, the diversity of the archaea community was very low, and 17 species were detected, belonging to three classes: Group I. 1a, Group I. 1b and Thermoplasmatata, which included 1 new and 13 new species. The results suggested that the ammonia-oxidizing archaea plays a key role in the process of the carbon-nitrogen circulation in the permafrost ecosystem in the region. (5) In order to clarify the driving mechanism of the vertical distribution of the bacterial community, the spatial and genealogical pattern of the bacterial community was further analyzed from the angle of ecology and evolution. The diversity analysis of species and genealogy shows that the bacterial community is not a random distribution along the core section of the frozen soil, but the distribution pattern of the distance attenuation is shown; in 5 sampling depths, the spectral structure of the bacterial community is random, However, all communities show that the average trend is toward the lineage; these results indicate that the ecological process of driving the vertical distribution of the bacterial community is mainly the deterministic ecological choice, but the random process also plays an important role.
【學位授予單位】：蘭州大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：Q938
，
本文編號：2338877
[Abstract]:Permafrost is an important part of the earth's land freeze and represents a key organic carbon reservoir. The microorganisms, including bacteria, archaea, phototrophic cyanobacteria and green algae, fungi and protozoa, constitute the main biomass and species diversity in the permafrost, and affect many important biogeochemical processes. In recent decades, the effects of global warming on the permafrost environment have been of great concern, and the permafrost and the greenhouse gases (carbon dioxide, The release of methane and nitrous oxide) is considered one of the main ways to feed the terrestrial ecosystem to the global atmospheric system. It is a hot issue for ecologists to determine the composition of the frozen soil microbial community and understand their functional roles and how they respond to climate change and permafrost. The Qinghai-Tibet Plateau is a unique and fragile ecosystem. The low-latitude and high-altitude permafrost in the region is particularly sensitive to climate change. However, compared with the two-pole region, the research on the micro-organism of the frozen soil in the Qinghai-Tibet Plateau is relatively weak, and it is difficult to provide scientific basis and data reference for the research of the frozen soil microorganisms in other parts of the world and the research of other disciplines in the region. In this paper, the physiological and biochemical characteristics, diversity and community structure of the frozen soil microorganisms (bacteria, archaea and fungi) were studied, and the spatial distribution pattern and the ecological driving mechanism of the frozen soil microbial community were discussed. The main results are as follows: (1) The total number of microorganisms in the permafrost of the Kunlun Mountains in the Qinghai-Tibet Plateau is between 108 and 109/ g, and the number of bacteria can be 103-106 CFU/ g of soil (dry weight); the phylogenetic analysis shows that the bacterial diversity is high and belongs to the actinomycete. A total of 44 genera of 5 taxa of the 5 groups of the genus Firmicin, Proteobacteria, Bacteroides, and Deinococcus-Therus, the dominant species are Arthrobacter, Psychrobacter, and Planococcus, The results of the physiological and biochemical characteristics of Bacillus and Microbacterium showed that the isolated bacterial strains were mostly cold resistant bacteria, and a few were cold and warm, and 93.6% and 49. 0% of the strains had the ability of alkali and salt tolerance, respectively. The number of cultivable fungi is very low, between 0 and 103 CFU/ g of soil (dry weight), belonging to 5 genera of Ascomyota and Baidota, which belong to the genus Geotrichum, Cladosporium, Alternaria, Rhodotorula and Cryptococcus. (2) 62 fungal species, including 25 new species, were found in the frozen soil of the Kunlun Mountains in the Qinghai-Tibet Plateau, including 25 new species, and the fungal community was attached to 10 classes of 3 groups of the Ascomycetes, Basidiomycetes and Mucor, with the highest diversity and relative abundance; Some of the fungus groups are widely present in the permafrost environment around the world, which may represent the cold or cold-resistant fungi in the world. The composition of the fungus community varies with the depth, and the difference between the active layer and the permanent freezing layer is significant, and the soil conductivity is an important factor affecting the composition of the fungus community. (3) A total of 191 species of bacterial species, including 19 new species and 108 new species, were detected in the frozen soil core of the Kunlun Mountain in the Qinghai-Tibet Plateau, and there were 19 new species and 108 new species. The diversity of the bacterial community decreased with the increase of the depth. in that active lay sample, the diversity is higher than that of the permanent freezing layer; the bacterial community also changes with the depth, and the composition difference of the community in the sample of the active layer is greater with respect to the permanent freezing layer; and the soil physical and chemical factors of the various measurement influence the composition of the bacterial community, in which the effect of the carbon-to-nitrogen ratio and the organic carbon content of the soil is particularly significant. (4) As compared with the bacteria, the diversity of the archaea community was very low, and 17 species were detected, belonging to three classes: Group I. 1a, Group I. 1b and Thermoplasmatata, which included 1 new and 13 new species. The results suggested that the ammonia-oxidizing archaea plays a key role in the process of the carbon-nitrogen circulation in the permafrost ecosystem in the region. (5) In order to clarify the driving mechanism of the vertical distribution of the bacterial community, the spatial and genealogical pattern of the bacterial community was further analyzed from the angle of ecology and evolution. The diversity analysis of species and genealogy shows that the bacterial community is not a random distribution along the core section of the frozen soil, but the distribution pattern of the distance attenuation is shown; in 5 sampling depths, the spectral structure of the bacterial community is random, However, all communities show that the average trend is toward the lineage; these results indicate that the ecological process of driving the vertical distribution of the bacterial community is mainly the deterministic ecological choice, but the random process also plays an important role.
【學位授予單位】：蘭州大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：Q938
，
本文編號：2338877
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