【作者】 赵小丽；

【导师】 宋立荣；

【作者基本信息】 中国科学院研究生院（水生生物研究所） ， 水生生物学， 2007， 硕士

【摘要】 水体富营养化的不断加剧,有毒蓝藻水华的频繁爆发,是造成水环境生态灾害的主要原因之一。蓝藻水华的控制一直是环境科学、生态学领域研究的重点,探索浮游藻类尤其是有毒蓝藻水华控制的行之有效的方法是非常迫切的。近20年来,我国对湖泊等水体富营养化进行了一系列研究与防治的实践,取得了一定的成绩,但富营养化污染总体状况仍呈持续恶化趋势,许多淡水湖泊相继发生了严重的产毒蓝藻“水华”。从全国范围防治富营养化污染的任务极为紧迫,急需研发高效安全的控藻、除藻方法。本文研究了常用的铜类杀藻剂(硫酸铜)抑制不同藻类生长的半有效浓度及该方法用于湖泊蓝藻水华控制中水生态系统的影响;探讨了一种可以吞噬微囊藻的金藻(Poterioochromonas sp.)的吞噬特性及在水华发生初期所起的作用,具体内容如下: 1. Cu2+对五株常见藻类——铜绿微囊藻Microcystis aeruginosa (PCC 7806),水华鱼腥藻Anabaena flos-aquae (FACHB 245),莱茵衣藻Chlamydomonas reinhardii (FACHB 479),斜生栅藻Scenedesmus obliquus (FACHB 416),以及小环藻Cyclotella sp. (FACHB 986)——生长抑制的EC50(Cu2+,48h)及毒性强弱顺序为铜绿微囊藻(46μg/l) >水华鱼腥藻(75μg/l) >小环藻(186μg/l) >莱哈衣藻(403μg/l) >斜生栅藻(515μg/l); 2.对武汉市两个小型富营养化城市湖泊——小月湖和小莲花湖,先后进行了3次使用硫酸铜对去除蓝藻“水华”的试验,每次进行为期约15天的跟踪实验,结果表明:硫酸铜对去除“水华”藻类、改善水体透明度有一定作用,但时效性约为10～15天;硫酸铜处理后,浮游植物种类发生更替的顺序为:蓝藻门-硅藻门/绿藻门-蓝藻门,这与Cu2+对藻类生长抑制实验的结果相吻合;硫酸铜处理后,水柱中微囊藻毒素含量迅速增加,但又很快的降低于处理前水平,时间为3～5天; 3.对金藻Poterioochromonas sp.吞噬单细胞藻类的特性进行了研究:金藻Poterioochromonas sp.能引起培养的单细胞微囊藻在短时间内大量消失;蓝藻“水华”发生期间的高温、偏碱性pH等环境条件不影响Poterioochromonas sp.吞噬微囊藻的速率;喂食不同饵料藻的Poterioochromonas sp.出发株吞噬微囊藻表现出一定的选择性,以产毒的饵料藻喂食的Poterioochromonas sp.出发株选择性高,微囊藻重新生长的比例更大;以非产毒的饵料藻喂食的Poterioochromonas sp.出发株吞噬选择性低,微囊藻重新生长的比例小且时效较长; Poterioochromonas sp.在天然水体中的生长速率与在培养液中的生长速率相近;4.室内模拟水华发生的实验表明:去除浮游动物的影响,Poterioochromonas sp.在水华的发生过程中能够生长,它对控制微囊藻水华有一定的作用。更多还原

【Abstract】 Nowadays, eutrophication and massive accumulations of planktonic microalgae as algal blooms in waterbodies have caused serious environmental problems. So it is very important to find effective methods to controll the growth of the bloom-forming algae.This paper focuses on: the effect of copper sulphate treatment, which is widely used as a global and empirical method to remove or control phytoplankton blooms, on different bloom-forming alga and on water ecosystem especially on the constructure of phytoplankton; effect of environmental factors, such as temperature, pH, and nutrition level, on the grazing speed of golden algae Poterioochromonas sp. to unicellular Microcystis, the species selectivity of Poterioochromonas sp. to Microcystis; and effect of Poterioochromonas sp. during the occurrence of Microcystis bloom. Main results are summarized as follows:1. According to algal growth inhibition tests, effect of copper on five species of Microcystis aeruginosa (PCC7806), Anabaena flos-aquae (FACHB245), Chlamydomonas reinhardii (FACHB 479), Scenedesmus obliquus (FACHB 416), Cyclotella sp. (FACHB 986)were illustrated. The EC50. of Cu2+ were in the increasing order for: M.aeruginosa (46μg/l), A. flos-aquae (75μg/l), Cyclotella sp. (186μg/l), Chlamydomonas reinhardii (403μg/l) and S. obliquus (515μg/l).2. In two eutrophic urban lakes, CuSO4?5H2O was used as algicide to control water bloom caused by cyanobacterial. The copper concentration applied was 102μg l-1 (as copper). Upon treatment, the transparence was increased and the algal biomass were decreased in the first 10-15 days, meanwhile, the dominant species were marked from cyanobacteria to diatom and green algae, but cyanobacteria re-emerged as dominant species after 10-15 days treatment. The short-term succession in species dominance seemed well correlated with the results of EC50 of species sensitiveity to copper. It was also found that, after treatment, the microcystins concetntration increased but soon droped to the level lower than that of before-treatment in 3-5 days.3. Golden alga Poterioochromonas sp. itself was responsible for the sudden disappearances of cultured Microcystis sp., but not bacteria or secretion of Poterioochromonas sp.. Temperature, pH and nutrition level would not affect the grazing speed of Poterioochromonas sp to unicellular Microcystis. Poterioochromonas sp. feeding on different strains of algae showed feeding selectivity on algae. Poterioochromonas sp. fed with nontoxic strains of algae would show lower selectivity and last longer time.4. In 10 L cuture system, lake water without zooplankton was used to simulate the occurrence of Microcystis bloom. It showed that Poterioochromonas sp. was able to grow in the lake water and play an active role in controlling the occurrence of unicellular Microcystis bloom in the system.更多还原