鄱阳湖湿地沉水植物群落与水体、底泥营养化及重金属污染的关系

发布时间：2018-01-20 21:32

本文关键词： 鄱阳湖沉水植物营养物重金属相关性分析除趋势典范对应分析　出处：《江西师范大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着各种营养盐与重金属等污染物质不断排入鄱阳湖,以及人类活动干扰的增强,鄱阳湖的水生生态系统及沉水植物群落已受到严重影响。课题选择鄱阳湖的南矶山、吴城、鄱阳县白沙洲与龙口、都昌县周溪与西源等典型湖滨湿地作为研究区,分别于2013年秋季及2014年春季等两个不同季节调查沉水植物群落并采集水体与底泥样品,测定分析各样点水体与底泥中氮、磷等营养盐以及重金属铜(Cu)、铅(Pb)、镉(Cd)等污染物的含量。以此为基础对鄱阳湖沉水植物的种类分布、植物群落与生物多样性进行研究;采用水质富营养化评价方法与TSIM回归模型对鄱阳湖水体进行评价;运用地累积指数法和潜在生态危害指数法对底泥重金属的污染现状进行评价;通过相关性分析和除趋势典范对应分析,寻找影响沉水植物群落的主要环境因子。论文得到国家自然科学基金(D41161035):“鄱阳湖典型湿地沉水植物群落结构及其水环境因子定量研究”的支持与资助。主要研究结果如下:(1)两个不同季节在研究区共发现沉水植物15种隶属于9科11属。其中,2014年春季共发现沉水植物11种,隶属于7科9属,其中轮藻(Chara vulgaris)为大型沉水藻类,其余种类皆为水生维管束植物。研究区分布较为广泛的物种为苦草(Valliisneria spiralis)和黑藻(Hydrilla vertivilla),而轮藻和大茨藻(Najas marina)是分布相对较少的物种。共发现12种沉水植物群丛类型,其中以苦草群丛与苦草+黑藻群丛居多。苦草是各个湖泊的优势植物,不同湿地优势物种及组成均有所不同。南矶山湿地白沙湖与常湖的沉水植物物种多样性较丰富,且分布较均匀。都昌与鄱阳白沙洲的物种多样性不高,且分布不均匀。两个不同季节中,南矶山湿地的白沙湖、常湖、三泥湾等各湖泊的物种组成比较稳定,优势植物都为苦草、黑藻和小茨藻,其群丛类型有所不同;白沙湖与常湖生物多样性指数变化不大,而三泥湾由于春季植物种群减少和分布不均匀,导致其生物多样性减少。(2)研究区水质良好,水质状况排序为:白沙洲、吴城南矶山都昌龙口,前3个研究区水体的总氮(TN)、总磷(TP)、化学需氧量(COD)基本达到地表水环境质量Ⅲ类水标准,龙口的水质最差,超出Ⅴ类水的标准。水体富营养化的两种评价方法结果都显示各样地的水体呈富营养状态。综合分析底泥中的全氮(TN)、全磷(TP)和有机碳(OC)含量,南矶山的常湖与三泥湾的营养盐含量均较高,都昌和鄱阳县龙口的营养物质含量都比较低,各样地底泥的有机质主要来源于高等植物,底泥有机质是其氮的主要来源。两个不同季节调查结果显示南矶山水体均达到Ⅲ类水标准,且秋季水体呈中营养状态,春季为富营养。两季中南矶山水体营养物质有显著性差异,而底泥无显著性差异。(3)各样点水体中(除都昌县周溪湿地Pb含量外),3种重金属含量均未超过地表水环境质量Ⅱ类标准限值,且3种重金属含量的大小为:ρ(Cu)ρ(Pb)ρ(Cd),鄱阳县龙口湖滨区的3种重金属含量相对较高,而白沙洲的较低。水体和底泥Cu、Cd含量最大值均出现在龙口,Pb最大值出现在周溪。南矶山两季水体与底泥中的重金属Cu、Pb含量差异性显著,Cd含量变化不大。地累积指数和潜在生态危害指数两种评价方法的评价结果均表明龙口底泥重金属的污染程度为中度,是研究区重金属污染最严重的区域,其余区域的污染程度均为中度以下。潜在生态风险指数结果显示,南矶山两季底泥的重金属污染为轻度污染。(4)Pearson相关性分析结果表明,水体透明度、水深、水体总氮含量与沉水植物的鲜重呈显著负相关;水深与沉水植物物种多样性呈极显著负相关,且水体总氮、总磷、Cu、Pb含量和底泥有机碳、全氮等均有显著相关性。通过对沉水植物群落样点与环境因子的除趋势典范对应分析(DCCA),结果表明,排序轴1主要反映水体透明度和水深,排序轴2主要反映水体Cu含量。综上分析,影响春季鄱阳湖沉水植物群落的主要环境因子为水深与水体透明,其它影响较显著的环境因子还包括水体营养物质以及Cu含量。在不同季节,影响南矶山湿地沉水植物群落的主要环境因子有所不同,2013年秋季沉水植物多样性与环境因子间无显著相关性,而2014年春季沉水植物多样性与水深、水体透明度均呈显著负相关。综合研究表明,鄱阳湖的水质总体良好,基本达到地表水环境质量Ⅲ类水标准,底泥重金属污染除鄱阳县龙口为中度污染外,其余区域底泥为较轻度污染。影响沉水植物群落的关键环境因子为水深和水体透明度,大多数沉水植物群落分布在水位较浅、水质较好的区域。南矶山湿地水位浅、水质良好,沉水植物种类多,且生物多样性丰富;而都昌水位高,水质较差,其生物多样性最低。对比分析南矶山湿地春、秋两季的水土环境指标与沉水植物群落结构,发现南矶山沉水植物的群落结构比较稳定,水体各项污染物的变化比较大,不同季节底泥各项指标相对稳定,且春季的水质更差;环境因子对沉水植物群落的影响春季比秋季更大。
[Abstract]:With a variety of nutrients and heavy metals and other pollutants flowing into the Poyang Lake, and enhance the disturbance of human activities, the aquatic ecosystem and submerged plant communities of Poyang Lake have been seriously affected. The paper choose Poyang Lake Nanjishan, Wucheng County, Poyang baisazhou and Longkou, Duchang county and the Western Zhou Xi source of typical wetland as study area respectively, in the autumn of 2013 and spring of 2014 two submerged plant communities in different seasons and collected water and sediment samples, analysis of water and sediment in the nitrogen, phosphorus and other nutrients and heavy metal copper (Cu), lead (Pb), cadmium (Cd) content of pollutants. The species distribution on the basis of submerged macrophytes in Poyang Lake, study on plant communities and biodiversity; the eutrophication evaluation method and TSIM regression model to evaluate the water of Poyang Lake; using the index of geoaccumulation And the potential ecological risk index of heavy metal pollution was evaluated; the correlation analysis and detrended canonical correspondence analysis, find the main environmental factors affecting the submerged plant communities. The National Natural Science Foundation of China (D41161035): "supported by Poyang Lake typical wetland macrophyte community structure and water environmental factors in quantitative research" the main results are as follows: (1) two different seasons in the study area were found in 15 kinds of submerged plants belonging to 9 families and 11 genera. Among them, in the spring of 2014 found a total of 11 kinds of submerged plants, belonging to 7 families and 9 genera, among them (Chara vulgaris) for CHAROPHYTE submersed algae, the other species are aquatic vascular plants. Study area is widely distributed species (Valliisneria spiralis) and eelgrass (Hydrilla vertivilla), and Hydrilla verticillata and stonewort najadaceae (Najas Marina) is a relatively small distribution A total of 12 species. Species cluster types found in Vallisneria cluster and Vallisneria spiralis + cluster in Hydrilla verticillata is the dominant plant. Vallisneria species and composition of various lakes, wetlands are different. The different advantages of Nanjishan wetland Baisha lake and lake often submerged plant species diversity is rich, and the distribution is uniform. Duchang and Poyang Baishazhou species diversity is not high, and the distribution is not uniform. In two different seasons in Nanjishan wetland Baisha lake, lake mud Bay often, three species in each lake are relatively stable, dominant plant Vallisneria spiralis, Hydrilla verticillata and n.minor, the cluster different types of changes; Baisha lake and lake often biodiversity index, while the three mud Bay because the spring plant population decreased and the distribution is not uniform, resulting in a decrease in biodiversity. (2) the study area good water quality, water quality in the order: the white sandbar, the southern Rocky Wu Cheng Yama Toma longkou, The first 3 of total nitrogen water (TN), total phosphorus (TP), chemical oxygen demand (COD) reached the surface water environmental quality standard class III water, Longkou the worst water quality, beyond the class V water standard. The results of two evaluation methods of eutrophication of the water body are displayed a comprehensive analysis of eutrophication. Total nitrogen in the sediment (TN), total phosphorus (TP) and organic carbon (OC) content, nutrient content of Chang Lake and three mud Bay Nanjishan the higher nutrient content, Longkou Duchang and Poyang county are relatively low, the organic matter of sediment the main source in higher plants, the sediment organic matter is the main source of nitrogen in two different seasons. The survey results show that the southern rocky landscape of the body reached the class III water standard, and autumn water is mesotrophic to eutrophic. In spring two season South Rocky Mountain eutrophication has significant differences, but no significant the difference of sediment (3). Every point in the water (except Duchang County Zhouxi wetland Pb content), 3 heavy metals did not exceed the limit of surface water environmental quality standard II, and 3 kinds of heavy metal content in size: P (Cu) = (Pb) P (Cd), 3 kinds of heavy metals in Poyang County Dragon Lake District the phase of high and low. Baishazhou water and sediment content of Cd Cu, the maximum values appeared in Longkou, Pb maximum in Zhouxi. Heavy metal Cu Nanjishan water and sediment in the two quarter, the content of Pb was significantly higher, Cd content changed little. The accumulation index and potential ecological risk the number of evaluation methods of evaluation results showed that the pollution degree of heavy metals in the sediment of Longkou is moderate, is the most serious heavy metal pollution in this area, the pollution degree of the rest of the region are moderate. The potential ecological risk index showed that the heavy metal pollution in Nanjishan two quarter is slightly polluted sediment (4). Pearson correlation analysis results showed that the water transparency, water depth, total nitrogen content of water and submerged plant fresh weight was negatively correlated; was negatively correlated with the depth of diversity of submerged plant species, and the total nitrogen, total phosphorus, Cu, Pb content and sediment organic carbon, total nitrogen had significant correlation by detrended canonical correspondence analysis of submerged plant community samples and environmental factors (DCCA), the results show that the 1 axis mainly reflect the water transparency and water depth, 2 axis mainly reflect the water content of Cu. Based on the analysis, the main environmental factors affecting the spring Poyang Lake submerged plant community for water depth and water transparency, environmental factors other significant effects include water nutrients and Cu content. In different seasons, the main environmental factors affecting plant communities in the southern Rocky Mountain Wetland submerged vary, submerged plant diversity and the autumn of 2013 No significant correlation between the environmental factors and the spring of 2014, submerged plant diversity and water depth, water transparency was negatively correlated. The comprehensive study shows that the overall water quality of Poyang Lake is good, basically reached the surface water environmental quality standard class III water, heavy metals in Poyang Longkou is moderately polluted, the rest of the region were relatively mild effect of pollution. The key environmental factors for submerged plant communities and water transparency depth, most of the submerged plant communities distributed in the shallow water area, the water quality is good. The Nanjishan wetland in shallow water, good water quality, submerged plant species, and abundant biodiversity; and the Duchang high level of water quality is poor, its biological diversity the lowest. Comparative analysis of Nanjishan wetland in spring, autumn two season soil environmental index and macrophyte community structure, found the southern Rocky Mountains of submerged macrophytes is relatively stable, water The variation of pollutants is relatively large. In different seasons, the indicators of sediment are relatively stable, and the quality of water in spring is worse. The influence of environmental factors on submerged macrophyte communities is greater in spring than in autumn.

【学位授予单位】：江西师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X524;Q948.8

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