【作者】 黄海强；

【导师】 姚维志；

【作者基本信息】 西南大学 ， 水产养殖学， 2008， 硕士

【摘要】 浮游生物在水体生态系统物质循环和能量流动中扮演着重要的角色。迄今,国内外对浮游生物的研究多集中在数量、生态特征以及评价水质等方面,关于江河泥沙沉降对浮游生物的影响的研究并不多见。因此,研究泥沙沉降对水体中浮游生物的影响具有十分重要的意义。本实验通过2006年11月到2007年11月4次对三峡库区重庆朝天门到秭归太平溪江段的水质、浮游生物、泥沙含量现状的调查,了解三峡库区朝天门到太平溪江段水质、浮游生物、泥沙含量的时空变化,通过对这些数据的分析,找出泥沙沉降和浮游生物之间的相互关系,为更好的保护三峡水库的水环境提供科学依据。1研究水域的泥沙变化规律三峡库区朝天门到秭归江段泥沙沉降非常明显。其中朝天门到云阳江段泥沙沉降迅速。到云阳后泥沙沉降速度趋于平缓,保持在一定范围。泥沙的沉降比例说明,在洪水期水中泥沙的粒径相比枯水期要大,且大粒径泥沙比例大。这正如河流中水体泥沙含量的特点:水体泥沙含量大小随季节发生变化,降雨季节泥沙含量大,干旱季节泥沙含量小。2研究水域泥沙沉降对水质指标变化的影响三峡库区朝天门到秭归江段,水中悬浮泥沙沉降在枯水期与DP的相关性不显著,在洪水期的影响有待进一步研究;NH₄⁺-N、NO₂^--N、NO₃^--N、T、DO、pH和电导率等水体水质指标四次采样变化趋势大体一致,与水中悬浮泥沙含量相关性不显著。3研究水域泥沙沉降对浮游植物的影响对浮游植物种类组成的调查结果表明,四次采样各采样点的浮游植物都十分丰富。浮游植物种类组成显示,整个研究期间共发现7门58属183种,与蓝藻门、硅藻门和绿藻门为主。四次采样浮游植物种类组成都有同样一个趋势:藻类种类由多到少,出现藻类的门类由少到多,生物量也逐渐增大。各采样点的藻类大多以硅藻、绿藻和蓝藻为主,从上游到下游黄藻、隐藻、裸藻和甲藻逐渐增多。在泥沙含量低的枯水期的三次采样结果显示浮游植物优势种从硅藻逐渐向绿藻或蓝藻转变,但泥沙含量多且沉降明显的洪水期采样结果则显示,除万州、石柱和巫山外,各采样点的浮游植物优势种都是硅藻。在三峡库区朝天门到秭归江段浮游植物年均生物量从上游到下游逐渐增大,浮游植物密度和生物量的变化趋势趋于一致。朝天门江段到秭归江段的浮游植物的Shannon-Weaver多样性指数呈波浪式变化,整体有下降趋势。4研究水域泥沙沉降对浮游动物的影响从本次实验的结果来看,四次采样浮游动物种类组成都有同一个趋势:种类由少到多,生物量也逐渐增大,特别是桡足类在种类和数量上都增加明显,各采样点的浮游动物以原生动物和轮虫为主。浮游动物的种类组成变化和浮游植物的种类组成变化刚好相反。泥沙沉降对浮游动物的种类有重要影响,随着泥沙的逐渐沉降,浮游动物的种类逐渐增加。随着泥沙的逐渐沉降,浮游动物生物量变化相对激烈,尤其是枝角类、桡足类和无节幼体,水中浮游动物生物量将逐渐增加。泥沙沉降一方面通过增加透明度而有利于浮游生物生长,另一方面,又可能通过带动营养物质沉降而不利于浮游生物生长。本实验的结果表明:三峡库区朝天门到秭归段泥沙沉降有利于浮游生物的生长。更多还原

【Abstract】 Plankton plays an important role in the material cycle of the water ecosystem and the flowing of energy. So far at home and abroad, most of the studies about plankton have been focused on the quantity, the ecological characteristics,the evaluation of the water quality, etc. Only a few studies had been about the impact of the sediment deposition on plankton. Therefore, it was significant to study the impact of the sediment deposition on plankton. During November 2006 and November 2007 we had investigated the water characteristics, plankton and the sediment’s content of the Three Gorges reservoir between Chaotianmen and Tai ping xi river four times, and learnt their changed in time and space. After analysing the data gained, we found out the mutual ralationship between the sediment deposition and plankton, which can provide a scientific basis for better protection of the water environment in the Three Gorges Reservior area.1 the law of the sediment’s changed in the waters studiedThe sediment deposition was very obvious from Chaotianmen to Zigui river. The sediment between chaotianmen and yunyang river depositted very fast. After the sediment move to the Yunyang, the speed tended to slow down and maintain a certain range. From the deposition of sediment, we can conclude the size of sediment was larger in the flood period than in the dry season. It was the same as the feature of the sediment’s content in the water. The quantity of the sediment changed as the seasons changes;the sediment content was high in rainfall season but low in dry season.2 on the waters of sediment deposition on the impact of sediment deposition on the changes of water’s index in waters studiedBecause the instruments in the experiment were inadequate, we could not get sufficient data about the impact of the suspended sediment’s deposition on the PO₄³-P, NH₄^--N, NO₂^--N in the water of the Three Gorges Reservoir between Chaotianmen and Zigui river, which needs further research; the diversification trend of the NO₃^-- N, T, DO, pH and electrical conductivity, and other indicators of water quality sampled the four times was nearly the same. 3 the impact of the sediment deposition on phytoplankton in the waters studiedThe survey of phytoplankton’s species composition showed that at the four sampling situses the phytoplankton was very rich. During the study period, the total of the phytoplankton species discovered was seven phylum,58 category and 183 kinds. Most of them belong to Cyanophyta, Bacillariophyta and Chlorophyta. The composition of the phytoplankton’s species sampled in four times appeares the same trend-algae’s species are from less to more, but the categories of species are from less to more, and the biomass was also gradually increasing. At each sampling situs the most were Cyanophyta, Bacillariophyta and Chlorophyta. Along the direction of the current, Xanthophyta、Cryptophyta、Euglenophyta and Pyrrophyta gradually increase. The three sampling results in the dry season with low sediment content showed that the dominant species of phytoplankton transforme gradually from Bacillariophyta to Chlorophyta or Cyanophyta, but the sampling results in the flooding period with high sediment content showed that the dominant specy of phytoplankton at each sampling situs is Bacillariophyta except Wanzhou,Shizhuand Wushan. From Chaotianmen to the Three Gorges Reservoir area in Zigui river the average annual biomass of phytoplankton was gradually increasing along the current direction, and the diversification tendence of the phytoplankton’s density and biomass becomes in a line. From Chaotianmen to Zigui,the Shannon-Weaver diversity index of phytoplankton changes undeely.4 the impact of sediment deposition on zooplankton in the waters studiedAccording to the results of the experiment, we had learnt that the species composition of zooplankton sampled had the same tendence-the species was from less to more, and the biomass was also gradually increasing. Particularly Copepoda had increased significantly in the type and quantity. The main of zooplankton at each sampling situs were protozoa and rotifers. The species composition of the zooplankton changed Contrarily to the phytoplankton .Sediment deposition had important influence on the types of zooplankton. The types of zooplankton gradually increased with the gradual deposition of sediment. The biomass of zooplankton changed relatively intensely, especially Cladocera、Copepoda and Young animal, and the biomass of the zooplankton will gradually increase.On the one hand was conducive to the growth of plankton and by increasing the transparency. On the other hand, it may lead the nutrients depositing so as to induce the detriment of plankton’s growth. The results of the experiment showed that the sediment deposition from Chaotianmen to Zigui river of the Three Gorges Reservoir area was conducive to the growth of plankton.更多还原