【摘要】：烏梁素海成為世界上沼澤化速度最快的湖泊之一,正向蘆葦沼澤→堿蓬鹽化草甸→白刺荒漠方向演化。本文探究了烏梁素海富營養(yǎng)化湖泊濕地演化過程中,水陸過渡帶沉積物以及土壤中氨氧化細菌群落的組成、豐度、親緣關(guān)系以及多樣性變化,結(jié)合濕地理化囚子探討基質(zhì)條件對氨氧化細菌群落結(jié)構(gòu)的影響；以及細菌群落的組成、豐度以及多樣性變化,結(jié)合土壤理化因子探討其對細菌群落結(jié)構(gòu)的影響。本文采用濕地總DNA提取法提取沉積物和土壤總DNA,對氨氧化細菌群落的amoA基因構(gòu)建克隆文庫,并進行測序,分析濕地沉積物與土壤過渡帶4個樣點中氨氧化細菌群落結(jié)構(gòu)的組成、豐度、親緣關(guān)系以及多樣性指標(biāo)；分析基質(zhì)條件變化對氨氧化細菌群落結(jié)構(gòu)的影響；以及對細菌群落的16S rDNA基因進行高通量測序,分析各樣品中細菌群落結(jié)構(gòu)的組成、豐度以及多樣性指標(biāo)；土壤理化性質(zhì)采用標(biāo)準(zhǔn)方法測定,分析其對細菌群落結(jié)構(gòu)的影響。主要得到以下幾方面的結(jié)論：第一、建立了具有自主知識產(chǎn)權(quán)的新的快速高效沉積物微生物總DNA提取方法。本文首次采用重鉻酸鉀溶液處理沉積物樣品,結(jié)合機械裂解與化學(xué)試劑裂解相結(jié)合的手段,直接裂解微生物細胞將其溶解于DNA提取緩沖液進而獲得高質(zhì)量的微生物總DNA。第二、富營養(yǎng)化湖泊濕地水陸過渡帶氨氧化細菌從與Nitrosomonas-like序列相似為主要優(yōu)勢類群向與Nitrosospira-like序列相似為主要優(yōu)勢類群轉(zhuǎn)變,群落結(jié)構(gòu)空間異質(zhì)性成因主要由總氮和水溶鹽總量這兩個基質(zhì)因子所主導(dǎo)。第三、沼澤化濕地及其過渡帶土壤中細菌群落形成空間異質(zhì)性的重要環(huán)境因子為總磷、水溶鹽總量和銨態(tài)氮。第四、氮是富營養(yǎng)化湖泊形成的重要因子,本文提出關(guān)于富營養(yǎng)化湖泊沉積物過量氮元素去除的微生物學(xué)機制可能為：氨氧化細菌將銨態(tài)氮氧化為羥氨,進一步轉(zhuǎn)化為亞硝態(tài)氮或硝態(tài)氮,這個過程耦合了硫化物的氧化過程,最終以氮氣的形式將沉積物中的化合態(tài)氮化物轉(zhuǎn)變?yōu)闅鈶B(tài)的氮氣排放到大氣中去以緩解含有大量氮元素的農(nóng)田退水排入烏梁素海對其生態(tài)系統(tǒng)功能造成的影響。
[Abstract]:Wuliangsuhai is one of the most rapidly swamp lakes in the world, and it is evolving towards the desert of Suaeda salsa. In this paper, the composition, abundance, phylogenetic relationship and diversity of ammonia-oxidizing bacteria community in sediments and soils of eutrophic lake wetland in Wuliangsuhai were studied. The effects of substrate conditions on the community structure of ammonia-oxidizing bacteria were studied. The composition, abundance and diversity of bacterial community, and the effects of soil physical and chemical factors on the structure of bacterial community were discussed. In this paper, a clone library was constructed by extracting total DNA, from sediment and soil by extracting total DNA from sediments and soil to construct a clone library of Ammonia-oxidizing bacteria (Amox) community, and sequenced it. The composition, abundance, phylogenetic relationship and diversity index of ammonia-oxidizing bacteria community in four sites of wetland sediment and soil transition zone were analyzed. The effects of substrate conditions on the structure of ammonia-oxidizing bacteria community were analyzed, and the 16s rDNA gene of the bacterial community was analyzed by high-throughput sequencing to analyze the composition, abundance and diversity of bacterial community structure in each sample. The physical and chemical properties of soil were determined by standard method, and the effects of soil physical and chemical properties on bacterial community structure were analyzed. The main conclusions are as follows: first, a new rapid and efficient DNA extraction method for sediment microorganisms with independent intellectual property rights was established. In this paper, potassium dichromate solution was used to treat sediment samples for the first time. Combined with mechanical cracking and chemical reagent cracking, microorganism cells were directly dissolved in DNA buffer solution to obtain high quality total microbial DNA.. Secondly, the ammonia-oxidizing bacteria in eutrophication lake wetland transition zone changed from Nitrosomonas-like sequence similarity as main dominant group to Nitrosospira-like sequence similarity as main dominant group. The spatial heterogeneity of community structure was mainly caused by two matrix factors, total nitrogen and total dissolved salt. Third, the important environmental factors for the formation of spatial heterogeneity of bacterial communities in the swamp wetland and its transitional zone are total phosphorus, total dissolved salt and ammonium nitrogen. Fourthly, nitrogen is an important factor in the formation of eutrophication lakes. The microbiological mechanism of excess nitrogen removal in eutrophic lake sediments may be as follows: ammonia-oxidizing bacteria oxygenate ammonium to hydroxyl ammonia. Which is further converted to nitrite or nitrate nitrogen, a process coupled with the oxidation of sulfides, In the end, the combined nitrogen in sediments is transformed into gaseous nitrogen in the form of nitrogen to be discharged into the atmosphere in order to mitigate the effect on ecosystem function of farmland retreating water with a large amount of nitrogen elements into the Wuliangsu Sea.
【學(xué)位授予單位】：內(nèi)蒙古大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：Q938

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