鄱陽湖濕地剖面土壤微生物群落結構及功能的變化特征
發(fā)布時間：2019-06-11 20:10
【摘要】：鄱陽湖濕地是我國最大的天然淡水湖泊濕地,季節(jié)性水位動態(tài)明顯,微地形復雜多變,擁有豐富的自然資源,隨著人們對濕地功能性認識的不斷高,鄱陽湖區(qū)濕地生態(tài)系統(tǒng)研究近年來受到學者們的普遍關注。對濕地土壤剖面的研究示,深層土壤中可能蘊含有大量的微生物資源,對濕地生態(tài)系統(tǒng)的物質轉化和能量循環(huán)具有重要影響。然而對于微生物群落的結構組成、功能、代謝活性如何隨著深度剖面分布,主要受何種因素影響,我們知之甚少且缺乏系統(tǒng)研究。因此,本研究以鄱陽湖濕地土壤為研究對象,樣地選擇在蚌湖(BH)、常湖池(CHC)、南磯山(東湖)(NJS)等三個典型區(qū),取樣土壤剖面深度為1m,分為5層(0-20cm、20-40cm、40-60cm、60-80cm、80-100cm)。采用16S rRNA高通量測序、q-PCR、Biolog-ECO等多樣研究方法,對土壤理化性質、胞外酶活性、碳源代謝活性、微生物生物量以及細菌豐富度和群落結構進行分析。以闡明鄱陽湖濕地土壤微生物群落結構及代謝功能的空間變化,尤其是沿土壤剖面深度的變化特征,為多微生物組學角度示土壤演變機制供一條新的途徑。結果表明:(1)鄱陽湖濕地土壤主要優(yōu)勢菌門為綠彎菌門(30.83%),其次是變形菌門(21.37%)和酸桿菌門(18.85%)。在更細的分類層次——科水平,主要的優(yōu)勢物種是Anaerolineaceae(17.49%),其次是Acidobacteriaceae_(Subgroup_1)(9.36%)和HSB_OF53-F07(8.00%)。與此同時,鄱陽湖濕地土壤細菌豐度(1.60×108-7.49×1010 copies/g)和Chao1指數(shù)(663-2664)也高于其它淡水濕地生態(tài)系統(tǒng)。使用METAGENassist進行基于細菌群落的代謝功能預測,結果顯示:表層(0-20cm)土壤中細菌群落的代謝功能主要包括硫酸鹽的還原(41.9%),氨氧化(35.8%),亞硝酸鹽的還原(33.3%),脫鹵(27.7%),硫化物的氧化(25.8%),木聚糖降解(20.1%),氮的固定(11.0%)等;深層(20-100cm)土壤中細菌群落的代謝功能主要包括氨氧化(37.7%),硫酸鹽的還原(34.3%),亞硝酸鹽的還原(27.8%),硫化物的氧化(25.7%),脫鹵(22.9%),甲烷氧化(20.0%),木聚糖降解(18.7%)。(2)鄱陽湖濕地土壤細菌豐度及群落結構沿土壤剖面深度顯著改變,且差異性主要表現(xiàn)在表層(0-20cm)土壤和深層(20-100cm)土壤之間,其中綠彎菌門、變形菌門以及酸桿菌門在濕地土壤剖面深度上有顯著的差異性。細菌群落代謝功能方面,反硝化功能(7.0%)和儲存聚羥基丁酸酯的功能(0.02%)只存在于表層土壤,而萘降解(0.9%)和硒酸鹽還原劑功能(0.04%)只存在于深層土壤中。值得注意的是,深層土壤中的甲烷氧化功能(20.00%)明顯的高于表層土壤(0.08%)。進一步研究發(fā)現(xiàn),盡管在不同的樣地間,土壤細菌群落結構存在顯著的差異,但差異性遠不及深度上的差異顯著。(3)鄱陽湖濕地土壤微生物功能特性(微生物生物量、胞外酶活性、碳源代謝功能)顯著受到土壤深度的影響,表層(0-20cm)土壤中微生物活性最高,土壤深度達到60cm以后,微生物活性開始穩(wěn)定,但深層土壤中仍然進行著由微生物參與的復雜代謝活動。此外,僅微生物碳源代謝活性(AWCD)在樣地間存在差異,土壤微生物生物量、胞外酶活性不隨樣地而發(fā)生改變,表明土壤微生物作為環(huán)境變化的敏感指標,其群落結構的改變會優(yōu)先于某些代謝功能的改變,以此來應對外界環(huán)境的變化。(4)通過相關性分析以及冗余分析(RDA)發(fā)現(xiàn),鄱陽湖濕地土壤微生物功能特性和細菌群落結構組成主要受到土壤有機質(AFDM)及營養(yǎng)元素(TOC、TN)的影響,除此之外,土壤含水量(SM)也是影響因素之一。其中AFDM、TOC和TN沿土壤剖面深度顯著減小是導致鄱陽湖濕地土壤微生物的功能活性以及細菌群落結構隨土壤剖面深度變化的主要原因;土壤SM在樣地間的差異性,則使得土壤微生物碳源代謝活性及細菌群落結構隨樣地不同而發(fā)生改變。(5)通過相關性分析以及冗余分析發(fā)現(xiàn),Bradyrhizobiaceae、4-29、Xanthobacteraceae與β-木糖苷酶(Bxyl)、過氧化物酶(Pero)、β-葡萄糖苷酶(Bglu)和土壤磷酸酶(Phos)的活性變化存在緊密的聯(lián)系,Spirochaetaceae與乙酰氨基葡萄糖苷酶(NAG)的活性變化相關。Acidothermaceae、1921-3、HSB_OF53-F07、Cystobacteraceae、sh765B-TzT-35是影響碳源代謝活性的最主要物種。綜上所述,鄱陽湖濕地土壤性質、土壤細菌群落結構、細菌豐富度和功能特性均隨著深度表現(xiàn)出顯著的差異,而在水平距離上差異并不明顯。與深層土壤(20-100cm)相比,盡管表層土壤(0-20cm)微生物的功能更為活躍,細菌豐度高,但是深層土壤(甚至到100cm深度)仍然具有復雜的細菌群落組成和較高的代謝功能活性,這一點與其他生態(tài)系統(tǒng)中土壤微生物的垂直分布不太一致。這就示我們在濕地生態(tài)系統(tǒng)中,不同深度的土壤微生物具有不同的群落組成和代謝功能,深層土壤的微生物在土壤演化中的作用值得關注。本研究的結果初步揭示了鄱陽湖濕地土壤微生物的空間分布規(guī)律,深化了我們對于濕地生態(tài)系統(tǒng)的認識。全面的、系統(tǒng)的了解濕地生態(tài)系統(tǒng),是濕地環(huán)境治理、資源保護、可持續(xù)發(fā)展的重要科學基礎。本項目特色:首次采用較先進的研究手段,系統(tǒng)研究了鄱陽湖濕地土壤微生物群落結構和功能特性的空間分布,為預測鄱陽湖濕地生態(tài)系統(tǒng)微生物的演化趨勢和功能活性供參考;較早的引入METAGENassist,將16S rRNA的高通量測序結果與群落代謝功能相聯(lián)系,幫助進一步了解濕地土壤沿剖面變化的土壤微生物的功能多樣性和重要性。
[Abstract]:Poyang Lake wetland is the largest natural freshwater lake wetland in China, the seasonal water level is dynamic, the micro-terrain is complex and changeable, has rich natural resources, The study of the wetland ecosystem in the Poyang Lake area has been widely concerned by the scholars in recent years. The study of the wetland soil profile shows that the deep soil may contain a large amount of microbial resources, which has an important effect on the material transformation and energy circulation of the wetland ecosystem. However, for the structure, function and metabolic activity of the microbial community, we know little about the influence of the distribution of the depth profile, and we know little about the system. Therefore, in this study, the soil of Poyang Lake wetland is used as the research object, and three typical areas such as the freshwater mussel (BH), the Changlaway (CHC) and the NJS (NJS) are selected. The depth of the sampling soil is 1 m, which is divided into 5 layers (0-20 cm,20-40 cm,40-60 cm,60-80 cm,80-100 cm). The soil physical and chemical properties, the extracellular enzyme activity, the carbon source metabolic activity, the microbial biomass and the bacterial richness and the community structure were analyzed by a variety of methods such as 16S rRNA high-throughput sequencing, q-PCR, Biolog-ECO and the like. The spatial variation of the structure and the metabolic function of the soil microbial community in the wetland of Poyang Lake, especially the change of the depth of the soil profile, is used to illustrate the soil evolution mechanism for a new route. The results showed that: (1) The main dominant bacteria in the wetland of Poyang Lake were the green lobacter (30.83%), followed by the strain (21.37%) and the acid bacteria (18.85%). The main dominant species were Anabaena (17.49%), followed by Acinetobacter _ (Subgroup _ 1) (9.36%) and HSB _ OF53-F07 (8.00%) at a finer level of classification. At the same time, the bacterial abundance (1.60-108-7.49-1010 copies/ g) and Chao1 index (663-2664) of the wetland in Poyang Lake are also higher than other freshwater wetland ecosystems. The results showed that the metabolic function of the bacterial community in the surface layer (0-20 cm) mainly includes the reduction of sulfate (41.9%), the ammonia oxidation (35.8%), the reduction of nitrite (33.3%) and the dehalogenation (27.7%). The oxidation of the sulfide (25.8%), the degradation of the xylan (20.1%), the fixation of nitrogen (11.0%), etc. The metabolic function of the bacterial community in the deep (20-100 cm) soil mainly includes ammoxidation (37.7%), reduction of sulfate (34.3%), reduction of nitrite (27.8%), Sulphide oxidation (25.7%), dehalogenation (22.9%), methane oxidation (20.0%), and xylan degradation (18.7%). (2) The soil bacterial abundance and community structure of the wetland in Poyang Lake are significantly changed along the soil profile, and the difference is mainly between the soil of the surface layer (0-20cm) and the deep layer (20-100 cm), among which, There was a significant difference in the depth of the soil profile of the wetland. In the aspects of bacterial community metabolism, the function of denitrification (7.0%) and the function of storing polyhydroxybutyrate (0.02%) only existed in the surface soil, while the function of microbial degradation (0.9%) and the function of the selenate reducing agent (0.04%) only existed in the deep soil. It is worth noting that the methane oxidation function (20.00%) in the deep soil is significantly higher than the surface soil (0.08%). Further studies have found that, although there is a significant difference in the structure of the soil bacterial community in different plots, the difference is far from that of the depth. (3) The microbial activity (microbial biomass, extracellular enzyme activity and carbon source metabolism) of the wetland in Poyang Lake was significantly affected by the depth of the soil, and the microbial activity was the highest in the surface layer (0-20 cm) and the soil depth reached 60 cm, and the microbial activity started to be stable. However, the deep soil still carries out complex metabolic activities involving the participation of microorganisms. in addition, only that metabolic activity of the microbial carbon source (AWCD) exist in the sample, the microbial biomass of the soil and the activity of the extracellular enzyme do not change with the sample, indicating that the soil microorganism is a sensitive index of environmental change, and the change of the community structure can take precedence over the change of certain metabolic functions, So as to cope with the change of the external environment. (4) The effect of soil organic matter (AFDM) and nutrient elements (TOC, TN) on the soil microbial function and the structure of the bacterial community was found by the correlation analysis and the redundancy analysis (RDA). In addition, Soil moisture content (SM) is also one of the influencing factors. in which the depth of the AFDM, TOC and TN is significantly reduced along the soil profile, resulting in the functional activity of the soil microorganisms in the Poyang Lake wetland and the main cause of the change of the bacterial community structure with the depth of the soil profile; the difference between the soil SM and the sample ground, The metabolic activity of the soil microbial carbon source and the structure of the bacterial community are changed along with the sample. (5) The activity changes of brayrhizobaiacae,4-29, Xanthomonas campestris (Bxyl), peroxidase (Pero), tomato-grape-glucoamylase (Bglu) and soil phosphatase (Pcos) have a close relationship through the correlation analysis and the redundancy analysis. The activity of Spirochaetacei was related to the activity of glycosaminoglucanase (NAG). Acdothermolaceae,1921-3, HSB _ O53-F07, Cysteobacter, sh765B-TzT-35 are the main species that affect the metabolic activity of the carbon source. In conclusion, the soil properties of the Poyang Lake wetland, the structure of the bacterial community of the soil, the richness of the bacteria and the functional characteristics of the wetland show a significant difference with the depth, and the difference in the horizontal distance is not obvious. Compared with the deep soil (20-100 cm), although the function of the surface soil (0-20cm) is more active and the bacterial abundance is high, the deep soil (even to the depth of 100 cm) still has complex bacterial community composition and higher metabolic function activity, This is not consistent with the vertical distribution of soil microorganisms in other ecosystems. This shows that in the wetland ecosystem, the soil micro-organisms at different depths have different community composition and metabolic functions, and the role of the micro-organisms in the deep soil is of great concern in the soil evolution. The results of this study preliminarily reveal the spatial distribution of soil microorganisms in Poyang Lake wetland and deepen our understanding of the wetland ecosystem. Comprehensive and systematic understanding of wetland ecosystem is an important scientific basis for wetland environmental management, resource protection and sustainable development. This project is characterized by the first use of advanced research means, the spatial distribution of the structure and functional characteristics of the soil microbial community in the wetland of Poyang Lake is systematically studied, and the evolution trend and function activity of the micro-organisms in the wetland ecosystem of Poyang Lake are provided for reference; and the earlier introduction of METAGENE, The high-throughput sequencing results of the 16S rRNA are associated with the community metabolic function to help further understand the functional diversity and importance of the soil microorganisms in the wetland soil along the profile.
【學位授予單位】：南昌大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：S154.3
本文編號：2497418
[Abstract]:Poyang Lake wetland is the largest natural freshwater lake wetland in China, the seasonal water level is dynamic, the micro-terrain is complex and changeable, has rich natural resources, The study of the wetland ecosystem in the Poyang Lake area has been widely concerned by the scholars in recent years. The study of the wetland soil profile shows that the deep soil may contain a large amount of microbial resources, which has an important effect on the material transformation and energy circulation of the wetland ecosystem. However, for the structure, function and metabolic activity of the microbial community, we know little about the influence of the distribution of the depth profile, and we know little about the system. Therefore, in this study, the soil of Poyang Lake wetland is used as the research object, and three typical areas such as the freshwater mussel (BH), the Changlaway (CHC) and the NJS (NJS) are selected. The depth of the sampling soil is 1 m, which is divided into 5 layers (0-20 cm,20-40 cm,40-60 cm,60-80 cm,80-100 cm). The soil physical and chemical properties, the extracellular enzyme activity, the carbon source metabolic activity, the microbial biomass and the bacterial richness and the community structure were analyzed by a variety of methods such as 16S rRNA high-throughput sequencing, q-PCR, Biolog-ECO and the like. The spatial variation of the structure and the metabolic function of the soil microbial community in the wetland of Poyang Lake, especially the change of the depth of the soil profile, is used to illustrate the soil evolution mechanism for a new route. The results showed that: (1) The main dominant bacteria in the wetland of Poyang Lake were the green lobacter (30.83%), followed by the strain (21.37%) and the acid bacteria (18.85%). The main dominant species were Anabaena (17.49%), followed by Acinetobacter _ (Subgroup _ 1) (9.36%) and HSB _ OF53-F07 (8.00%) at a finer level of classification. At the same time, the bacterial abundance (1.60-108-7.49-1010 copies/ g) and Chao1 index (663-2664) of the wetland in Poyang Lake are also higher than other freshwater wetland ecosystems. The results showed that the metabolic function of the bacterial community in the surface layer (0-20 cm) mainly includes the reduction of sulfate (41.9%), the ammonia oxidation (35.8%), the reduction of nitrite (33.3%) and the dehalogenation (27.7%). The oxidation of the sulfide (25.8%), the degradation of the xylan (20.1%), the fixation of nitrogen (11.0%), etc. The metabolic function of the bacterial community in the deep (20-100 cm) soil mainly includes ammoxidation (37.7%), reduction of sulfate (34.3%), reduction of nitrite (27.8%), Sulphide oxidation (25.7%), dehalogenation (22.9%), methane oxidation (20.0%), and xylan degradation (18.7%). (2) The soil bacterial abundance and community structure of the wetland in Poyang Lake are significantly changed along the soil profile, and the difference is mainly between the soil of the surface layer (0-20cm) and the deep layer (20-100 cm), among which, There was a significant difference in the depth of the soil profile of the wetland. In the aspects of bacterial community metabolism, the function of denitrification (7.0%) and the function of storing polyhydroxybutyrate (0.02%) only existed in the surface soil, while the function of microbial degradation (0.9%) and the function of the selenate reducing agent (0.04%) only existed in the deep soil. It is worth noting that the methane oxidation function (20.00%) in the deep soil is significantly higher than the surface soil (0.08%). Further studies have found that, although there is a significant difference in the structure of the soil bacterial community in different plots, the difference is far from that of the depth. (3) The microbial activity (microbial biomass, extracellular enzyme activity and carbon source metabolism) of the wetland in Poyang Lake was significantly affected by the depth of the soil, and the microbial activity was the highest in the surface layer (0-20 cm) and the soil depth reached 60 cm, and the microbial activity started to be stable. However, the deep soil still carries out complex metabolic activities involving the participation of microorganisms. in addition, only that metabolic activity of the microbial carbon source (AWCD) exist in the sample, the microbial biomass of the soil and the activity of the extracellular enzyme do not change with the sample, indicating that the soil microorganism is a sensitive index of environmental change, and the change of the community structure can take precedence over the change of certain metabolic functions, So as to cope with the change of the external environment. (4) The effect of soil organic matter (AFDM) and nutrient elements (TOC, TN) on the soil microbial function and the structure of the bacterial community was found by the correlation analysis and the redundancy analysis (RDA). In addition, Soil moisture content (SM) is also one of the influencing factors. in which the depth of the AFDM, TOC and TN is significantly reduced along the soil profile, resulting in the functional activity of the soil microorganisms in the Poyang Lake wetland and the main cause of the change of the bacterial community structure with the depth of the soil profile; the difference between the soil SM and the sample ground, The metabolic activity of the soil microbial carbon source and the structure of the bacterial community are changed along with the sample. (5) The activity changes of brayrhizobaiacae,4-29, Xanthomonas campestris (Bxyl), peroxidase (Pero), tomato-grape-glucoamylase (Bglu) and soil phosphatase (Pcos) have a close relationship through the correlation analysis and the redundancy analysis. The activity of Spirochaetacei was related to the activity of glycosaminoglucanase (NAG). Acdothermolaceae,1921-3, HSB _ O53-F07, Cysteobacter, sh765B-TzT-35 are the main species that affect the metabolic activity of the carbon source. In conclusion, the soil properties of the Poyang Lake wetland, the structure of the bacterial community of the soil, the richness of the bacteria and the functional characteristics of the wetland show a significant difference with the depth, and the difference in the horizontal distance is not obvious. Compared with the deep soil (20-100 cm), although the function of the surface soil (0-20cm) is more active and the bacterial abundance is high, the deep soil (even to the depth of 100 cm) still has complex bacterial community composition and higher metabolic function activity, This is not consistent with the vertical distribution of soil microorganisms in other ecosystems. This shows that in the wetland ecosystem, the soil micro-organisms at different depths have different community composition and metabolic functions, and the role of the micro-organisms in the deep soil is of great concern in the soil evolution. The results of this study preliminarily reveal the spatial distribution of soil microorganisms in Poyang Lake wetland and deepen our understanding of the wetland ecosystem. Comprehensive and systematic understanding of wetland ecosystem is an important scientific basis for wetland environmental management, resource protection and sustainable development. This project is characterized by the first use of advanced research means, the spatial distribution of the structure and functional characteristics of the soil microbial community in the wetland of Poyang Lake is systematically studied, and the evolution trend and function activity of the micro-organisms in the wetland ecosystem of Poyang Lake are provided for reference; and the earlier introduction of METAGENE, The high-throughput sequencing results of the 16S rRNA are associated with the community metabolic function to help further understand the functional diversity and importance of the soil microorganisms in the wetland soil along the profile.
【學位授予單位】：南昌大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：S154.3
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