【作者】 高洪生；

【导师】 张玉珍；

【作者基本信息】 福建师范大学 ， 自然地理学， 2011， 硕士

【摘要】 随着九龙江北溪梯级电站的建设,形成了大量的电站库区,北溪河流“湖库化”现象严重。近2年库区水体富营养化严重,并且在2009年发生甲藻水华事件。因此,迫切需要研究湖库化河流水体富营养化原因及其驱动机制,对防治北溪水体富营养化有重要的理论和现实意义。本文在相关监测数据的基础上对九龙江北溪库区水体营养状态进行了综合评价,对氮、磷营养盐、叶绿素a以及浮游植物状况作定性和定量的分析和探讨,最后,提出了水体富营养化的防控措施。主要结论如下：(1)枯水期的富营养化评价发现北溪水体整体上处于中营养-轻度富营养化水平,个别水体的营养水平较高(马洋溪和龙津溪的回水区水体)。北溪干流水体营养状况存在明显的空间差异,基本呈现干流上游和下游高,中游低。(2)北溪干流库区水体氮、磷营养盐浓度普遍比支流库区偏高,枯水期更加突出。综合氮磷浓度比的特征和2009年“水华”爆发时的数据分析,初步判断磷是北溪干流库区水体的主要限制营养盐,氮可能是新桥溪库区的限制性营养盐,磷是龙潭湖水体的限制性营养盐,但是在北溪水体中可能还存在氮、磷限制不确定的因素,突出表现在干流段水体越靠近上游,受氮营养盐控制越强,越靠近下游,磷营养盐控制性越强,说明北溪水体富营养化原因复杂。(3)从时空分布上看,江东库区(包括马洋溪和龙津溪回水区)和龙潭湖水体中叶绿素a浓度处于较高水平,其它干支流库区水体叶绿素a浓度总体较低,年均值大多在10mg／m3以下；叶绿素a浓度在枯水期略高于丰、平水期的浓度。从全流域水体来看,总磷与叶绿素a的相关性较显著,成正相关,其关系式为：p=56.482×p(TP)+2.3589 (r=0.251 p=0.009)北溪水体在枯水期月份,水温对于叶绿素a的增长密切相关,PH、溶解氧和高锰酸盐指数也有一定的联系。(4)北溪库区水体浮游植物以硅-绿藻为主,其中马洋溪和龙津溪的回水区以及龙潭湖各月份的藻类细胞密度较大,其他库区水体中藻类细胞密度较小；枯水期时各库区藻类密度相对较大。春、夏秋季,各库区各水体藻类数量比较接近,为硅藻型,冬季库区水体藻类数量有所上升,藻类优势种有所改变,10月份期间则逐渐演变为以硅、绿、蓝藻混合型,或者由硅藻演变为绿藻或蓝藻。藻类数量与高锰酸盐指数、水温和溶解氧相关性较好,其中水温是枯水期间藻类生长繁殖的关键因素。(5)根据北溪水体富营养化程度、营养盐来源及负荷分析结果,从污染源控制、梯级电站调度、完善流域监测体系、河流生态环境保护等几个方面提出防控对策,以减缓水体富营养化趋势。更多还原

【Abstract】 With the building of the cascade hydropower stations in the north Jiulong River, many hydropower stations reservoirs areas came into being and the "being lakes and reservoirs" is very serious. The eutrophication of the water in the reservoir areas is becoming serious in recent two years and in 2009, blooms of the dinoflagellate hydration occurred. Therefore, it is an urgent issue to study the reasons and the mechanism of the eutrophication of river with dam, which has important theoretical and practical significance.The objectives of this study gives an overall evaluation to the waters of Nord Stream reservoir areas of Jinlong River on the basis of related testing data, and analyses the characteristics of the water nutrition salt,chla and phytoplankton from quantitative and qualitative perspective. Finally, it offers the measures to prevent the waters from eutrophication. The main conclusions of this paper as follows:(1) In dry period, the water in Nord Stream is mesotrophic-eutrophic,Some waters is more eutrophic(the waters in Mayang River and Longjin River). There are spatial differences in the level of eutrophication in Nord main stream.(2) The concentration of TP and TN in the waters of Nord main stream reservoirs areas is higher than that in the branch stream reservoirs areas. The contract is much more prominent in dry period. From the analysis of the characteristics of the concentration ratio of TN and TP and the 2009 "dinoflagellate " event, It can be asserted that TP is the main limit nutrient salts in the waters of the Nord main Stream reservoir areas; TN may be the main limit nutrient salts in the waters of xinqiao River reservoir areas; TP is the limit nutrient salts in the waters of Longtan Lake reservoir areas. There may be also uncertain factors, like TN and TP limit, which can be seen from the following phenomenon:the nearer to the upstream waters in the main stream, the stronger of the control of TN; the nearer to the downstream waters in the main stream, the weaker of the control of TN. This phenomenon means that the reasons for the eutrophication in the waters of the Nord Stream are complicated.(3) In spatial and temporal distribution, the concentration of Chla in the waters of Jiangdong reservoir areas(including Mayang River and Longjin River backwater area) and Longtan Lake is in a very high level while the concentration of chlorophyll a in the waters of other main and branch streams reservoir areas is generally low with an annual average of below 10mg/m3. The concentration of Chla is higher in dry period than that in the wet and level period. From the waters of the whole basin, the relation between the TP and Chla is very obvious:they are positively related and their relations are:ρ=56.482×ρ(TP)+2.3589 (r=0.251 p=0.009). In dry months, the temperature and the increase of Chla is closely related and there are certain relations among PH, DO and CODmn.(4) Diatom-chlorophyta is the main phytoplankton in the waters of Nord Stream reservoir areas. The alga cells in the mouth of Mayang River, Longjin River and Longtan Lake are denser than that of other reservoir areas. The algae cell density of every reservoir area is relatively bigger in dry seasons. The number of the alga cell which are diatom in all the reservoir areas are very close in winter, summer and autumn while the number increases and the dominant species are changing in winter. The dominant species are changed into the mixture of diatom, chlorophyta and cyanothece or the diatom is changed into chlorophyta or cyanothece in October. The number of the alga, the permanganate index, the temperature of water, and the DO correlate well and the temperature of water is the main factor that cause alga to grow in dry season.(5) According to analysis of eutrophication, the source and load of the nutrient salt of the waters in the Nord Stream, this thesis gives control measures from the perspective of the control of the pollution source, the ecological management of the power stations, the perfection of the detection system in the river basin and the ecological and environmental protection of the rivers to reduce the eutrophication of waters.更多还原