鄱阳湖河湖交错带丰水期微生物群落特征研究

发布时间：2018-08-17 19:21

【摘要】：鄱阳湖是我国的第一大淡水湖,对调节长江中下游水位,维持生态平衡起着重要的作用。近年来,随着江西省经济建设的加快和城市化水平的不断发展,鄱阳湖的污染状况也日渐加剧。微生物作为水环境中的重要组成部分,既受到水质因子的影响,同时也对湖泊水质有着反作用。本研究通过研究2016年鄱阳湖河湖交错带丰水期表层水体的水质理化指标、微生物多样性指数和细菌群落组成结构,得出主要研究结论如下:(1)鄱阳湖河湖交错带丰水期表层水体水质污染情况严重,其中总氮含量和总磷含量均超标严重。从氮磷比数据来看,影响鄱阳湖河湖交错带丰水期表层水体富营养化的主要限制性因素是磷限制。同时鄱阳湖河湖交错带丰水期表层水体各项污染物指标在空间上存在着显著的空间分布差异:其中,饶河、赣江和瑶湖的电导率水平明显高于其他区域;而在赣江、饶河和南矶山等区域总氮含量要高于其他区域;总磷含量较高的区域为瑶湖、湖口过江水道和南矶大桥段。(2)人类活动对鄱阳湖河湖交错带表丰水期表层水体水质的影响非常明显,总氮含量和总磷含量较高的区域都是人类农业生产和航运较为频繁的区域。然而,就人类活动对污染物的贡献率来看,人类活动对总磷的贡献率要大于对总氮的贡献率。饶河和赣江上游都是我国较为重要的有色金属开采基地,导致饶河和赣江水质中电导率指数较高;而修水上游由于工业基础较为薄弱,生态系统较为完整,使得修水成为了鄱阳湖水质较好的区域。(3)通过对本研究所采集的11个样本中微生物多样性和丰富度指数进行分析,发现所有样本中,湖口过江水道、吴城赣江入湖口和大湖池等区域的ACE指数相对较高,而南矶大桥段和赣江与修水交汇口的ACE指数相对较低。就微生物多样性指数而言,湖口过江水道的微生物多样性指数最高,达到5.44,而南矶山碟形湖的微生物多样性指数最低,仅有3.9。(4)对本研究所采集的11个样本进行高通量测序得到333794条有效碱基序列,对所获得的有效碱基序列进行OTU分类共得到1193个OTU。通过对细菌群落结构分析,发现所采样本中所有细菌分属于34个门、414个属和678个种。其中在门水平上的主要优势细菌群落为(Proteobacteria)拟杆菌门(Baceroidetes)、放线菌门(Actinobacteria)、和蓝藻门(Cyanobacteria);在属水平上的优势细菌群落为hgcI_clade、CL500-29_marine_group、Rheinheimera、Sporichthyaceae_unclassified和Flavobacterium;在种水平上的优势细菌群落为hgcI_clade_unclassified(12.3%)、hgcI_clade_uncultured_bacterium(8.6%)、CL500-29_marine_group_unclassified(6.1%)、Sporichthyaceae_unclassified(4%)和Rheinheimera_uncultured_gamma_proteobacterium(3.6%)。(5)对所测得出的细菌群落结构进行单因素分析和相似性聚落分析发现,不同采样点之间的细菌群落在门水平、属水平和种水平上都存在着显著的差异性。说明不同的污染物因子和不同的污染程度对微生物群落结构有着重要的影响。
[Abstract]:Poyang Lake is the largest freshwater lake in China, which plays an important role in regulating the water level of the middle and lower reaches of the Yangtze River and maintaining ecological balance. In recent years, with the acceleration of economic construction and the continuous development of urbanization in Jiangxi Province, the pollution situation of Poyang Lake is becoming more and more serious. Microorganisms, as an important part of the water environment, are affected by water quality factors. In this study, the physical and chemical indexes, microbial diversity index and bacterial community composition of the surface water of the Poyang Lake River-Lake Ecotone in 2016 were studied. The main conclusions are as follows: (1) Pollution of the surface water in the Poyang Lake River-Lake Ecotone during the flood season. From the data of nitrogen-phosphorus ratio, phosphorus limitation is the main limiting factor affecting eutrophication in the surface water of the Poyang Lake Riverlake ecotone during the flood season. Differences: Among them, the conductivity of Raohe, Ganjiang and Yaohu lakes is obviously higher than that of other regions; while the total nitrogen content of Ganjiang, Raohe and Nanjishan is higher than that of other regions; the areas with higher total phosphorus content are Yaohu Lake, the river-crossing channel of Hukou and the Nanji Bridge section. (2) Human activities on the surface water quality of the Poyang Lake ecotone during the flood season. However, the contribution rate of human activities to total phosphorus is higher than that to total nitrogen. Raohe and the upper reaches of Ganjiang River are important nonferrous metal mining areas in China. Base, leading to the Raohe and Gan River water quality conductivity index higher; and Xiushui upstream due to the weak industrial base, the ecosystem is more complete, making Xiushui Poyang Lake water quality is better area. (3) Through the analysis of 11 samples collected in this study, microbial diversity and richness index found in all samples. The ACE index of the estuary crossing the river, the inlet of Wucheng Ganjiang River and the Great Lake Pool are relatively high, while that of Nanji Bridge and the junction of Ganjiang River and Xiushui River are relatively low. Only 3.9. (4) 333 394 valid base sequences were obtained from 11 samples collected by our institute by high-throughput sequencing, and 1193 OTUs were obtained by OTU classification. The dominant bacterial communities at phylum level were Baceroidetes, Actinobacteria, and Cyanobacteria; at genus level, the dominant bacterial communities were hgcI_clade, CL500-29_marine_group, Rheinheimera, Sporichthyaceae_unclassified and Flavobacterium; and at species level, the dominant bacterial communities were HgcI_clade, CL500-29_marine_group, Rheinheimera, Sporichthyaceae_unclassified and Flavoterium. The bacterial communities were hgcI_clade_unclassified (12.3%), hgcI_clade_uncultured_bacterium (8.6%), CL500-29_marine_group_unclassified (6.1%), Sporichthyaceae_unclassified (4%) and Rheinheimera_uncultured_gamma_proteobacterium (3.6%). The results showed that there were significant differences in bacterial community at gate level, genera level and species level among different sampling sites, indicating that different pollutant factors and different pollution levels had important effects on microbial community structure.
【学位授予单位】：江西师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X172;X524

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