Knowledge Resource Center for Ecological Environment in Arid Area
| 沙埋对干旱沙区生物结皮层细菌群落结构和多样性的影响 | |
| 其他题名 | Impacts of Sand Burial on Bacterial Community Structure and Diversity Inhabiting Biocrusts |
| 滕嘉玲 | |
| 出版年 | 2017 |
| 学位类型 | 硕士 |
| 导师 | 方广有 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 细菌作为生物结皮(以下简称结皮)层中数量最多的微生物类群，在结皮的形成演替、碳氮循环和有机质分解中发挥关键作用，其群落结构和多样性变化可以敏感地反映沙区的生态功能和环境变化。作为干旱沙区最常见的干扰之一的沙埋可以通过改变结皮所处的微生境条件，影响结皮的结构和功能。那么，在这个过程中，沙埋是否会引起结皮层细菌群落结构和多样性的改变，进而影响结皮的结构和功能呢？目前还缺乏相关报道。本文利用高通量测序技术，通过对0(对照)、0.5(浅层) 和10 mm (深层)沙埋处理后的腾格里沙漠东南缘沙坡头人工固沙植被区蓝藻结皮、真藓结皮和藻-地衣混生结皮层细菌群落物种组成与丰度的测定，研究了沙埋对结皮层细菌群落结构和多样性的影响。结果表明：(1) 沙坡头地区结皮层细菌以放线菌、变形菌、蓝藻、浮霉菌、拟杆菌和酸杆菌等为主，不同类型结皮的优势菌群不同：蓝藻结皮层的优势菌群为蓝藻，真藓结皮和混生结皮层优势菌群均为变形菌。(2) 沙埋导致该地区结皮层细菌群落结构组成发生明显改变，细菌群落对沙埋的响应因结皮类型而异。无沙埋时，蓝藻结皮层细菌群落的优势菌群为蓝藻，沙埋后蓝藻丰度降低，变形菌和放线菌丰度随之增加，成为优势类群；真藓结皮和混生结皮层丰度最高的菌群均为变形菌，沙埋后放线菌成为群落优势类群。此外，研究发现浅沙埋增加了固氮蓝藻—席藻属和念珠藻属等关键功能菌丰度，但深沙埋降低了二者的丰度。(3) 沙埋增加了蓝藻结皮和真藓结皮层细菌群落的丰富度和多样性，但两者的增加程度随沙埋厚度不同存在差异：蓝藻结皮层细菌群落的丰富度和多样性随沙埋厚度增加而增加；真藓结皮层细菌群落的丰富度和多样性是浅沙埋时候最高。沙埋降低了混生结皮层细菌群落的丰富度和多样性，且随沙埋厚度增加降低愈显著。上述沙埋对干旱沙区生物结皮层细菌群落结构与多样性的改变，与结皮遭受沙埋后功能改变存在一定联系。因而本研究为深入理解沙埋对结皮结构和生态功能影响的生物学机制提供了理论依据，并为全面评估沙埋对干旱沙区生态系统结构和功能的影响提供了一定的参考。 |
| 英文摘要 | Bacteria, as a key component of biocrusts, play the primary role in nutrient cycle, carbon and nitrogen cycle and soil organic matter decomposition of biocrusts in deserts. Changes in bacterial community structure and diversity inhabiting can significantly reflect the variations of ecological function and environment of desert area. Sand burial is a common environmental stress of the biocrusts in arid and semiarid areas, which can change the surroundings of biocrusts and then influence their structure and function. Whether the sand burial causes the changes of bacterial community structure and diversity inhabiting biocrusts? If so, whether associations exist between these changes with the ecological functions of biocrusts? There have not seen the relevant report at present.We adopted the high-throughput sequencing techniques to investigate the effects of sand burial on bacterial community structure and diversity inhabiting biocrusts dominated by cyanobacteria, algal-lichen (mixed crusts)and Bryum argenteum (moss crusts), which following sand burial at a depth of 0 (control), 2 (shallow) and 10 mm (deep) in Shapotou, the southeastern edge of the Tengger Desert. Bacterial community species composition, abundance variation, and diversity indices including the Shannon-Wiener diversity and the richness indices Chao and abundance-based coverage estimator were compared among soil samples of biocrusts that suffered burial at various depths. The results showed the followings: (1) The dominant bacterial phyla inhabiting biocrusts included Actinobacteria, Proteobacteria, Cyanobacteria, Planctomycetes, Bacteroidetes, and Acidobacteria. And different types of biocrusts have different predominant bacteria; the dominant bacterial phyla inhabiting cyanobacteria crusts, moss crusts and mixed crusts were Cyanobacteria, Cyanobacteria and Proteobacteria, Actinobacteria and Proteobacteria, respectively;(2) Principal coordinate analysis showed that sand burial induced significant changes in bacterial community composition and the response of bacterial community to sand burial varied with biocrusts types. Sand burial increased the abundance of Actinobacteria while decreased the abundance of Cyanobacteria and Proteobacteria. So the predominant bacteria inhabiting cyanobacteria crusts were Cyanobacteria, Proteobacteria and Actinobacteria following 0, 2 and 10 mm burial depths, respectively. The bacteria with the highest abundance inhabiting moss crusts were Cyanobacteria or Proteobacteria, which were replaced by Actinobacteria after sand burial. By contrast, the predominant bacteria inhabiting mixed crusts were always Actinobacteria and Proteobacteria. In addition, the abundance of bacteria with critical function in bacterial community, such as nitrogen fixing bacteria—Phormidium and Nostoc increased following shallow burial and decreased following deep burial;(3) The species richness and microbial diversity inhabiting biocrusts increased following sand burial, but the extent of increase was different among the three biocrusts; the species richness and microbial diversity inhabiting cyanobacteria crusts increased with the burial depth; while the moss and mixed crusts subjected to shallow burial had the highest richness indices, and the two crusts subjected to deep burial had the highest diversity indices.The above influences that various depths of sand burial exerted to bacterial community and diversity inhabiting biocrusts were tightly related to functional variations of biocrusts led by burial. Thus the study offered the theoretical foundation for further understanding of the influence mechanism of sand burial on the structure and ecological functions of biocrusts in arid desert areas. |
| 中文关键词 | 生物结皮 ; 高通量测序技术 ; 沙埋 ; 细菌 ; 群落结构和多样性 |
| 英文关键词 | biocrusts high-throughput sequencing techniques sand burial bacteria community structure and diversity |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 生态学 |
| 来源机构 | 中国科学院西北生态环境资源研究院 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287964 |
| 推荐引用方式 GB/T 7714 | 滕嘉玲. 沙埋对干旱沙区生物结皮层细菌群落结构和多样性的影响[D]. 中国科学院大学,2017. |
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