贺江浮游藻类群落结构特征与水华研究

发布时间：2019-07-04 17:55

【摘要】：贺江是珠江流域西江水系的一级支流,同时也是贺州市的主要饮用水源,其水质安全对贺州市社会稳定和经济发展具有十分重要的意义。2014年贺江上游的水源水库龟石水库、中游的合面狮水库相继暴发大面积的蓝藻水华和甲藻水华,造成当地居民的饮水困难。本研究为了探索两座水库藻类水华暴发的关键影响因素,对贺江流域的浮游藻类群落动态和水质情况进行全面调查,进而分析探讨造成水华暴发和消亡的环境因素,采用Carlson指数、Shannon-Wiener多样性指数及Pielou均匀度指数等方法对贺江水环境和浮游藻类进行评价,运用多元统计分析法进一步分析主要环境因子对浮游藻类群落组成的影响,提出两座水库不同藻类水华暴发的关键环境因子,为贺江水华防治及其水质管理提供依据。主要研究结论如下:1)贺江流域共检出浮游藻类7门130种,丰水期7门63种,枯水期5门103种,浮游藻类群落组成以硅藻、绿藻和蓝藻门为主,丰水期绿藻门居多,硅藻门次之,藻细胞密度平均值为2.13×106cells/L;枯水期硅藻门最多,藻细胞密度平均值为3.71×106cells/L;优势种主要有变异沟链藻、颗粒沟链藻、集星藻、水华微囊藻、四尾栅藻、卷曲鱼腥藻、小球衣藻、小颤藻、小球藻、啮蚀隐藻和短小舟形藻。2)RDA分析表明,贺江浮游藻类群落分布主要受到氮磷营养盐影响,综合营养状态指数评价贺江水质是中营养水平,贺江源头龟石水库的藻细胞密度含量较高,丰水期、枯水期均高达107数量级,发生藻类水华的潜在风险较高。3)贺江上游龟石水库蓝藻水华暴发期间检出浮游藻类66种,主要以绿藻、硅藻和蓝藻为主,水库表层藻细胞总密度平均值为1.56×108cells/L,水华严重区段峡口(G3样点)藻细胞总密度最高,达到5.36×108cells/L,微囊藻细胞密度占98.09%,相应的叶绿素a浓度为74.48μg/L,6月16日~6月19日,藻细胞总密度变化范围为1.31×107~3.90×108cells/L,微囊藻细胞密度占比例为52.17%~96.22%,6月26日,藻细胞总密度变化范围为4.76×106~9.60×106cells/L,微囊藻密度变化范围为2.09×106~4.32×106cells/L,占比例为43.78%~49.92%。水华优势种惠氏微囊藻细胞密度随时间推移呈现逐渐降低的趋势,并且垂直方向藻细胞密度集中分布在表层及水下5m处,随着水深呈现降低趋势。4)龟石水库由于特殊的地域特征,主要受到支流汇入的污染物影响比较严重,集水区内的污染物主要来自规模化养殖,其次为农业面源及农村生活污染,因此,要加强控制水库周边的污染,降低外源污染物对水库的胁迫,从而缓解水库的富营养程度,有效防范水体藻类水华的暴发。5)贺江中游合面狮水库甲藻水华暴发初期3月1日,仅发现合面狮水库坝首有水华现象,3月8日~3月15日水华暴发严重期,库区段合面狮水库坝首和步头码头均发现水华现象,拟多甲藻细胞密度最高分别达到6.64×107cells/L、2.39×107cells/L,分别占总细胞密度的97.96%、92.69%,相对应的叶绿素a浓度分别达到833μg/L和251μg/L,3月底至4月初水华逐渐消退,库区段拟多甲藻细胞密度变化范围为3.32×105cells/L~1.62×106cells/L,叶绿素a浓度变化范围为0.93~12.4μg/L;河流段新忠码头未发现水华现象,藻细胞总密度变化范围为1.13×105~5.83×105cells/L,叶绿素a浓度变化范围为0.06~1.97μg/L,拟多甲藻主要集中在表层至水下5m处,随水体深度的增加呈现降低趋势。6)RDA分析结果表明,拟多甲藻与pH、CODMn和NP营养盐呈显著正相关,与水力停留时间(HRT)呈现正相关性,降雨是导致此次水华消退的主要原因,可见对于营养型水体,水动力因素对水华的生消至关重要,可通过水动力调控防范藻类水华的发生。
[Abstract]:He River is a first-class branch of the Xijiang River system in the Pearl River basin. It is also the main source of drinking water in Hezhou City. Its water quality is very important to the social stability and economic development of Hezhou City. The large-area blue-green algae bloom and the algae bloom in the middle reaches of the Lishi reservoir have caused the local residents to drink water. In order to explore the key influencing factors of the algal bloom in two reservoirs, the research on the dynamics and water quality of the planktonic algae in the Hejiang river basin is carried out, and the environmental factors causing the outbreak and extinction of the water bloom are analyzed, and the Carlson index is adopted. Shannon-Wiener diversity index and Pielou evenness index were used to evaluate the water environment and the planktonic algae, and the effect of the main environmental factors on the community composition of the planktonic algae was further analyzed by the method of multivariate statistical analysis, and the key environmental factors for the outbreak of different algae bloom in two reservoirs were put forward. And provides the basis for the prevention and treatment of the water and the quality of the water. The main research conclusions are as follows:1) There are 130 planktonic algae in the Hejiang river basin,63 species in the dry season, and 103 in the dry season, and the planktonic algae communities are mainly composed of diatoms, green algae and blue-green algae. the average density of the algae cells is 2.13-106 cells/ L, the average number of the algae cells in the dry season is at most, the average of the density of the algae cells is 3.71-106 cells/ L, and the dominant species mainly have the variation of the channel-chain algae, the granular trench-chain algae, the algae-collecting algae, the water-China microcystin, the four-tail-grid algae, the curling fish-Anabaena, the small-ball-coated algae, the microbiophylla and the chlorella, 2) RDA analysis indicated that the distribution of the planktonic algae in the Hejiang River was mainly affected by the nutrient salt of nitrogen and phosphorus. The comprehensive nutrition state index was used to evaluate the water quality of the Hejiang River, and the density of the algae cells in the Shiraishi reservoir at the source of the Hejiang River was high. There are 66 species of planktonic algae, mainly from the green algae, the diatom and the blue-green algae, and the average density of the algae cells in the surface of the reservoir is 1.56 to 108 cells/ L, which is up to the order of 107 on the order of 107 in the dry season. The total density of the algae cells was up to 5.36%108 cells/ L, the density of microcystin was 98.09%, the corresponding chlorophyll a concentration was 74.48. m u.g/ L, and the total density of the algae cells was 1.31-107-3.90%108 cells/ L. The density of microcystin was 52.17%-96.22%, the total density of microcystin was 4.76-106-9.60-106 cells/ L, and the density of microcystin was 2.09-106-4.32-106 cells/ L, accounting for 43.78% ~ 49.92%. the density of the microcystin in the water-hua dominant species is gradually reduced over time, and the density of the algae cells in the vertical direction is distributed at the surface layer and the water under the water of 5 m, and the trend of reducing the water depth is reduced. (4) the tortoise-stone reservoir is characterized by special geographical characteristics, the pollutants in the water-collecting area mainly come from the large-scale culture, secondly, the agricultural non-point source and the rural life pollution, therefore, the pollution of the periphery of the control reservoir is enhanced, the stress of the foreign pollutants on the reservoir is reduced, So as to relieve the rich nutrition of the reservoir and effectively prevent the outbreak of the water bloom of the water body. In the reservoir area of the reservoir area, the water bloom was found at the head of the dam and the head of the foothead. The highest density of the quasi-multicellular algae was 6.64,107 cells/ L, 2.39 and 107 cells/ L, respectively, which accounted for 97.96% and 92.69% of the total cell density, respectively, and the corresponding chlorophyll a concentration was 833ug/ L and 251ug/ L, respectively. From the end of March to the beginning of April, the water bloom gradually disappeared. The variation range of the density of the proposed multi-dinoflagellate cells in the reservoir area was 3.32-105 cells/ L-1.62-106 cells/ L, the variation range of the concentration of chlorophyll a was 0.93-12.4. m u.g/ L, the water-bloom phenomenon was not found in the Xinzhong terminal of the river section, and the variation range of the total density of the algae cells was 1.13-105-5.83-105 cells/ L. The concentration of chlorophyll a was in the range of 0.06-1.97. mu. g/ L, which was mainly concentrated on the surface layer to 5 m under the water, and the decreasing trend with the increase of the depth of the water. There is a positive correlation with the hydraulic retention time (HRT), which is the main cause of the decline of the water bloom. It is found that for the nutrient type water body, the water power factor is very important to the biological elimination of the water bloom, and the generation of the algae bloom can be prevented by the water power control.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X522

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