黄河三角洲滨海湿地微生物群落和功能的研究
吕笑非
学位类型博士
导师于君宝
2015-11
学位授予单位中国科学院研究生院
学位授予地点北京
关键词湿地生态系统、土壤微生物群落、微生物多样性、高通量测序、整合分析
摘要湿地与森林、草地、农田并称四大陆地生态系统,发挥着不可代替的生态功能,具有重要的社会功能和经济价值。微生物是湿地生态系统的活跃的组成部分。湿地微生物通过生物地球化学过程,推动着湿地生态系统的物质循环和能量流动,还在提高湿地初级生产力、维护生物多样性稳定、净化环境污染等方面发挥重要作用。微生物群落的结构和功能对环境的变化十分敏感,是评价土壤质量变化重要指示因子。黄河三角洲滨海湿地是中国暖温带地区最完整、最广阔、最年轻的滨海河口湿地生态系统性。它是世界上受到海陆交汇作用最活跃的河流三角洲之一。目前还需要进一步认知黄河三角洲滨海湿地中微生物群落的结构和功能。因此揭示湿地微生物群落结构和功能的变化规律,明确微生物群落在黄河三角洲滨海湿地中的作用,阐明微生物群落结构和功能变化的驱动因子,对深入认识黄河三角洲滨海湿地系统的生态功能具有重要意义。
本文利用整合分析方法系统分析了全球湿地生态系统中的细菌和古菌的群落多样性。根据受环境的影响不同,在黄河三角洲滨海湿地中设置了潮滩湿地(1976-1996年清水沟黄河故道附近)和新生湿地(本文将1996年后至今的入海口附近的湿地相对于其他湿地定义为新生湿地)作为本文研究中定义的新生湿地。在两种滨海湿地中各设置一条能够表征植被变化和环境梯度的样带研究滨海湿地微生物群落多样性。依据受潮汐影响程度将潮滩湿地样带划分为潮下带、潮间带、潮上带,依据植被演替序列在新生湿地样带划分为盐滩区、碱蓬区、柽柳区、芦苇区和白茅区。于2012年7月(夏)、10月(秋)、2013年2月(冬)、5月(春)从两条样带采集土壤并提取DNA。通过Ion Torrent高通量测序技术和PICRUSt构建虚拟宏基因组技术研究湿地微生物群落结构和功能,并分析了环境因子对微生物的影响,得到了如下结论:
(1)全球湿地中的细菌序列主要分布在以下5个门中:Proteobacteria、Bacteroidetes、Acidobacteria、Firmicutes和Actinobacteria,丰富度最高的种为FlavobacteriumGp1NitrosospiraNitrosomonas。全球湿地中古菌序列全部归属在Euryarchaeota 和Crenarchaeota内,丰富度最高的古菌属为FervidicoccusMethanosaeta。稀释性曲线分析表明,目前全球湿地土壤中细菌和古菌的物种多样性分别只发现了45%和56%,说明目前对湿地中的微生物多样性认知还不充分。
(2)黄河三角洲滨海湿地中90%以上的土壤细菌所分属在Proteobacteria、Chloroflexi、Bacteroidetes、Actinobacteria、Acidobacteria、Gemmatimonadetes和Firmicutes中。其中潮滩湿地的细菌群落的α-多样性在冬季显著降低。新生湿地的α-多样性沿着盐滩区到白茅区升高,在不同季节中也有显著差异。潮滩湿地和新生湿地的细菌群落组成在不同植被中差别显著,细菌群落组成之间的相似度与采样点之间的空间距离相关。潮滩湿地的细菌群落组成对低温影响更敏感。
(3)潮滩湿地和新生湿地的土壤微生物虚拟宏基因组在不同植被和季节中的变化趋势同细菌群落结构的相似但变幅较小,表明微生物群落在功能组成上比结构组成上更稳定。相关于碳代谢和氮代谢的功能基因在潮滩湿地的冬季下降明显,在新生湿地的不同植被群落中差别明显。
(4)在潮滩湿地和新生湿地中,微生物群落结构和功能变化的驱动因子不同。潮滩湿地中温度的季节变化是影响微生物群落的主要环境因子,新生湿地中盐度和硝态氮则是主要影响因子。同时,土壤质地对微生物群落的影响也不容忽视。鉴于所测的环境因子对土壤微生物群落变化的解释度不足40%,说明还有很多其他影响因子引起微生物群落的变化。
综上所述,黄河三角洲细菌群落的结构和功能受到季节和植被的影响而变化。在不同类型的湿地中,影响微生物群落结构和功能的驱动因子也不同。因此,本研究结果可加深湿地生态系统的微生物群落结构及功能的认知程度,为维护湿地生态系统功能提供了重要的理论基础和参考依据。
其他摘要Wetland is the border zone between the water and terrestrial systems. Wetland plays important roles in the environment, principally flood control, carbon sink and shoreline stability. Soil microorganisms are a basic part of the wetland ecosystem and microbial activities are crucial to the functions of wetland systems. Soil microorganisms play a key role in nutrient cycle and energy flow in wetlands. Moreover, they are essential for maintaining biological diversity, ecological balance, and sustainable development in wetlands. The microbial diversity reflects the environmental changes and can be considered as a sensitive indicator of soil quality in wetlands. The Yellow River Delta is the largest and youngest coastal estuary wetland in China. It is one of the most active regions of land-ocean interaction among the large river deltas in the world. With the deterioration of the ecological environment and the further research on the wetland ecosystem, however, the value of ecological environment in the Yellow River Delta has been increasingly recognized. Therefore, it is necessary to investigate the changes of microbial community structure and function and elucidate the effect of environmental factors on bacterial communities in the Yellow River Delta.
This study examined the bacterial and archaeal diversity from a worldwide range of wetlands soils and sediments using a meta-analysis approach and estimated the current coverage of the microbial diversity in global wetlands. We selectively investigated two typical wetlands in the Yellow River Delta, tidal flat (near the estuary of the Yellow River since 1976 to1996) and newly formed wetland (near the esturary of the Yellow River since 1996) (considered the newly-formed wetland in our study). We established three sampling plots along the series of tidal flat (subtidal flat, intertidal flat, and supratidal flat) and five sampling plots based on the vegetation succession in the newly formed wetland (Saline bare land, Suaeda salsa, Tamarix chinesis, Phragmites australis and Typha orientalis). Sampling was performed in each of the four seasons: July 2012 (summer), October 2012 (fall), and February 2013 (winter), May 2013 (spring). Soil bacterial community structure and function were analyzed by 16S rRNA genes using the Ion Torrent PGM platform and imputed metagenomes. The findings as follow:
(1)   Over 90% bacterial sequences in worldwide wetland were classified within five phyla, Proteobacteria, Bacteroidetes, Acidobacteria, Firmicutes, and Actinobacteria. The genus Flavobacterium was the dominant bacteria in wetlands, followed by Gp1, Nitrosospira, and Nitrosomonas. Of the archaeal sequences analyzed, all of them were classified within two phyla: Euryarchaeota and Crenarchaeota. The dominating archaeal genera were Fervidicoccus and Methanosaeta. Rarefaction analysis showed that 45% of bacterial and 56% of archaeal species-level diversity in wetland soils and sediments have been presented, indicating the relative low species-level diversity in witnessed wetlands.
(2)   The dominant phyla were Proteobacteria, Chloroflexi, Bacteroidetes, Actinobacteria, Acidobacteria, Gemmatimonadetes, and Firmicutes, which represented over 90% of all classified sequences across all samples. The α-diversity of bacterial community of tidal flat decreased significantly in winter. The α-diversity of bacterial community of newly formed wetland increased from saline bare land to the Typha orientalis, and had significant differences among seasons. The bacterial community structure was significantly different among plots, no matter in tidal flat or in newly formed wetland. Bacterial communities in same plot were clustered together, and the distances between bacterial communities represented plots locations. Bacterial community structure in the tidal flat was more sensitive to that in newly formed wetland.
(3)   The imputed metagenomes had smaller differences among plots and seasons than bacterial community structure, indicating the more stable of bacterial community function. The predicted functional profiles influencing biogeochemical processes, such as nitrogen metabolism, methane metabolism, vitamins metabolism and energy metabolism, were limited in winter in the tidal flat, and were significantly different among plots in newly formed wetland.
(4)   The driving forces of microbial community structure and function in the Yellow River Delta differed between tidal flats and newly formed wetland. Seasonal temperatural change was the major contributing factor in tidal flats, while salinity and nitrate were the main limited factors in newly formed wetlands. The contributions of factors affecting microbial community structure and function in the Yellow River Delta were less than 40%, indicating that there were still many unknowns in wetlands.
Taken together, the microbial community diversity is still limited in wetland ecosystem. Bacterial community structure and function differ significantly among seasons and vegetation. The driving factors are different in different typical wetlands in the Yellow River Delta. Our study improves the microbial community structure and function in wetland ecosystem, and provides scientific evidence for wetland ecosystems conservation and restoration in future.
语种中文
文献类型学位论文
条目标识符http://ir.yic.ac.cn/handle/133337/13821
专题中国科学院烟台海岸带研究所知识产出_学位论文
作者单位中国科学院烟台海岸带研究所
第一作者单位中国科学院烟台海岸带研究所
推荐引用方式
GB/T 7714
吕笑非. 黄河三角洲滨海湿地微生物群落和功能的研究[D]. 北京. 中国科学院研究生院,2015.
条目包含的文件
文件名称/大小 文献类型 版本类型 开放类型 使用许可
黄河三角洲滨海湿地微生物群落和功能的研究(7534KB)学位论文 开放获取CC BY-NC-SA浏览 请求全文
个性服务
推荐该条目
保存到收藏夹
查看访问统计
导出为Endnote文件
谷歌学术
谷歌学术中相似的文章
[吕笑非]的文章
百度学术
百度学术中相似的文章
[吕笑非]的文章
必应学术
必应学术中相似的文章
[吕笑非]的文章
相关权益政策
暂无数据
收藏/分享
文件名: 黄河三角洲滨海湿地微生物群落和功能的研究.pdf
格式: Adobe PDF
所有评论 (0)
暂无评论
 

除非特别说明,本系统中所有内容都受版权保护,并保留所有权利。