發(fā)布時間：2018-04-18 18:16

  本文選題：16S + rRNA　； 參考：《中國地質(zhì)大學(xué)(北京)》2016年博士論文

【摘要】：本研究以我國原生高砷地下水典型地區(qū)內(nèi)蒙古河套盆地杭錦后旗作為研究區(qū),將微宇宙實驗與微生物分子生物學(xué)方法相結(jié)合,通過研究高砷地下水和沉積物中的微生物多樣性及其群落結(jié)構(gòu)特征,分析高砷含水層沉積物中的功能微生物群落,并與水文地球化學(xué)參數(shù)相結(jié)合,探討微生物群落在高砷地下水運移富集過程中的作用機理。得到以下主要認(rèn)識:(1)地下水樣品的微生物多樣性與砷污染水平有關(guān),砷濃度相對較低的地下水樣品的微生物多樣性更大。細(xì)菌群落結(jié)構(gòu)組成也隨著地球化學(xué)條件(如氧化還原電位等)的變化而不同。(2)針對沉積物的高通量測序的CCA分析及beta多樣性分布的聚類結(jié)果表明,取樣深度、砷、硫和有機物含量等是影響沉積物細(xì)菌群落結(jié)構(gòu)的主要因素;16S rRNA克隆文庫結(jié)果也表明,沉積物微生物多樣性隨深度的增加而減小。(3)高砷含水層中的砷遷移受土著硝酸鹽還原菌(如Pseudomonas sp.等)、鐵還原菌(如Aquabacterium sp.、Thauera sp.、Georgfuchsia sp.、Methyloversatilis sp.、Clostridium sp.和Rhodoferax sp.等)、硫酸鹽還原菌(如Spirochaetales sp.、Desulfuromonadales sp.、Geobacter sp.、Desulfobacca sp.和Desulfosporosinus sp.等)以及砷還原菌的影響。鐵還原菌在氧化有機碳的同時,使鐵氧化物發(fā)生還原性溶解,從而使鐵氧化礦物表面的砷解放出來,促進地下水中砷的遷移。(4)沉積物中天然不穩(wěn)定有機碳含量具有生物可利用性,足夠支持上述微生物介導(dǎo)的生物化學(xué)活動。室內(nèi)微宇宙實驗證實,未加有機碳源的厭氧連續(xù)培養(yǎng)中,沉積物砷被大量釋放出來,且所釋放的砷以As(III)為主。(5)土著微生物對砷的歸宿也有重要影響。X射線近邊吸收結(jié)構(gòu)分析顯示,部分沉積物含有大量的與有機物和硫化物結(jié)合態(tài)的砷,且這些沉積物樣品中存在大量的鹵素呼吸菌Dehalococcoides和硫酸鹽還原菌。在有機物存在的情況下,Dehalococcoides菌和Deltaproteobacteria的對As(V)、SO_4~(2-)和Fe(III)的還原作用可形成固態(tài)沉淀如Fe(II)-As(V)或As-S,將砷固定在黃鐵礦中。(6)沉積物中存在與細(xì)胞質(zhì)砷還原基因arsC(解毒)和呼吸砷還原基因arrA(呼吸)的功能基因,這些功能基因的存在促進了As(V)的還原。深層沉積物的微生物對As(V)還原作用更強,這與深層沉積物中存在異養(yǎng)砷還原菌(DARPs)有關(guān),這些菌與已知的DARPs Desulfosporosinus Y5,Sulfurospirillum barnesii SES-3和Bacillus selenitireducens MLS10相似。
[Abstract]:The research on Hangjinhouqi Inner Mongolia Hetao Basin in typical regions of China native high arsenic groundwater as the research area, combining the microcosm experiments and microbial molecular biology method, through the research of high arsenic groundwater and sediment microbial diversity and community structure characteristics, analysis of high arsenic water functions of microbial communities in sediments, and combined with the hydrogeochemical parameters, to explore the mechanism of microbial communities in high arsenic groundwater migration and enrichment process. The results are as follows: (1) groundwater samples of microbial diversity associated with arsenic pollution levels, relatively low concentration of arsenic in groundwater samples of microbial diversity greater. Bacterial community composition with geochemical conditions (such as redox potential) vary. (2) for high-throughput sequencing of CCA in sediments analysis and beta diversity distribution The clustering results showed that the depth of sampling, arsenic, sulfur and organic matter content are the main factors influencing sediment bacterial community structure; 16S rRNA clone library showed that diversity increased with the depth of sediment microbial decreases. (3) high arsenic aquifers in the arsenic migration from native nitrate reducing bacteria (such as Pseudomonas sp.), iron reducing bacteria (such as Aquabacterium sp., Thauera sp., Georgfuchsia sp., Methyloversatilis sp., Clostridium sp. and Rhodoferax sp.), sulfate reducing bacteria (such as Spirochaetales sp., Desulfuromonadales sp., Geobacter sp., Desulfobacca sp. and Desulfosporosinus sp.) and arsenic reducing bacteria. The effects of iron reducing bacteria in organic oxidation carbon, iron oxide reduction of dissolved, so that the surface of the iron oxide minerals arsenic liberated, promote arsenic in groundwater migration. (4) natural sediment instability The machine has a carbon content of bioavailability, sufficient biochemical activities support the microbe mediated. Confirmed indoor microcosm experiments, anaerobic without organic carbon source in continuous culture, is a lot of arsenic in sediments released, and the release of arsenic by As (III). (5) the incidence of soil microorganisms arsenic also has an important influence on.X ray absorption near edge structure analysis showed that part of sediments contain large amounts of organic and sulfide bound with arsenic, and the sediment samples in the presence of a large number of halogen respiratory bacteria Dehalococcoides and sulfate reducing bacteria. In the presence of organic matter, Dehalococcoides bacteria and Deltaproteobacteria of As (V), SO_4~ (2-) and Fe (III) reduction can form solid precipitation such as Fe (II) -As (V) or As-S, will be fixed in the arsenic in pyrite. (6) and cytoplasmic gene arsC has original arsenic in sediments (detoxification) and respiratory arsenic Reduction of gene arrA (respiratory) genes of these genes was enhanced by the presence of As (V) reduction. The deep sediment microorganisms on As (V) reduction is stronger, arsenic reducing bacteria and heterotrophic the deeper sediments (DARPs), these bacteria with known DARPs Desulfosporosinus Y5, Sulfurospirillum barnesii SES-3 Bacillus selenitireducens and MLS10 are similar.

【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：P641;P593

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