【作者】 任向科；

【导师】 刘正文；

【作者基本信息】 暨南大学 ， 水生生物学， 2009， 硕士

【摘要】 附着藻类是水体环境变化最敏感的指示生物之一,其数量、群落结构能较好地反映水环境状况,是水质生物学评价的重要参数。对大镜山水库附着藻类群落结构动态变化的研究表明,水库上各区A、B、C中优势藻类均为硅藻,其中常见种类有桥弯藻（Cymbella sp.）、曲壳藻（Achnanthes sp.）、异极藻（Gomphonema sp.）、颗粒直链藻最窄变种（Melosira.granulatavar.angustissima）、舟形藻（Navicula sp.）。蓝藻门的蓝纤维藻（Dactylococcopsis sp.）、巨颤藻（Oscillatoria princeps）、湖丝藻（Linmothrix sp.）和绿藻门的四尾栅藻（Scenedesmusquadricauda）、微小四角藻（Tetraedron minimum）也是重要组成部分,说明该水库水质已呈中—富营养状态。同时发现A、B、C三个区域的附着生物生物量和水体营养盐含量有较好的正相关关系,C区营养盐含量相对较高对应该区附着生物生物量也较高。从保持水体营养盐循环角度分析,人工基质上的附着生物是一个氮、磷库,能保持水体中大量的营养盐。为了研究人工基质对水体水质的影响,在大镜山水库设置原位围隔。发现人工基质对有罗非鱼的水体水质起到很大的改善作用。人工基质对总磷（TP）、颗粒磷、叶绿素a和悬浮物（SS）的去除率分别达到57.1%、51.26%、89.86%和65.17%。对水体的透明度也有很大的改善作用。人工基质对正磷酸盐(pO₄^3--P)和各形态的氮含量有一定的改善作用,但是差异不显著。在非养殖水体中,人工基质能稳定降低水体中各形态氮的含量,降低水体叶绿素、悬浮物（SS）和化学需氧量(COD_Mn)含量,但效果不明显。使各形态磷的浓度相对于对照组有一定升高。人工基质改善养殖水体水质可能主要是通过生物营养竞争和化感作用抑制浮游藻类的生长,促进鱼类粪便的沉降,降低了总悬浮颗粒物的含量,从而也降低了水体总磷（TP）浓度。在没有罗非鱼的水体中,水体营养盐含量较低,但是对水体水质的改善效果并不理想。所以,人工基质更适合于在较高营养盐浓度水体中应用。在实验室条件下模拟了人工基质对有外源营养输入(氮:2mg·L^-1·week^-1;磷:0.1mg·L^-1·week^-1)的人工基质—螺系统中营养盐的影响。结果显示:附着藻类能有效去除水体中的营养盐。总磷（TP）、正磷酸盐的浓度从实验开始时的0.4 mg·L^-1和0.036 mg·L^-1左右降低到实验结束时的0.1 mg·L^-1和0.01 mg·L^-1左右。总氮（TN）浓度、氨氮（NH₄⁺-N）浓度从实验开始时的4 mg·L^-1和2.3 mg·L^-1左右降低到实验结束时的1.2 mg·L^-1和0.4mg·L^-1,去除率达到95%和85%以上。人工基质的放置能有效抑制浮游植物的生长,有效去除水体悬浮颗粒物,大大提高水体的溶解氧饱和度以及水体中的pH值。环棱螺的牧食加快了水体营养盐的循环,但是对附着藻类群落结构影响不大。更多还原

【Abstract】 Periphyton is one of the most sensitive indicator organism for the variation of water environment.Quantity and community of periphyton are important water quality parameter of biological evaluation,since they can reflect the condition of water environment properly.The study of periphyton community dynamic variation of Dajingshan reservoir shows that diatom is dominant species in area A,B and C,Cymbella sp.,Achnanthes sp.,Gomphonema sp., Melosira.granulata var.angustissima and Navicula sp.are common species.Dactylococcopsis sp., Oscillatoria princeps,Linmothrix sp.of green algae,and Scenedesmus quadricauda and Tetraedron minimum of Cynaophyta also are important part of periphyton community in this reservoir.The results indicated that water quality is in mesotrophic level.At the same time,there is a positive correlation between periphyton biomass and nutrients contents.Nutrient content in area C is relatively higher,and periphyton biomass is also higher than the other two areas.In the terms of maintaining circulation of nutrients,periphyton on artificial substrate is a pool of nitrogen and phosphorus,and can keep numerous nutrients in water body.In-situ mesocosm experiments was set-up in Dajingshan reservoir,in order to study influences of artificial substrate on water quality.Results showed that artificial substate could improve water quality greatly which contains tilapia.Artificial substrates can eliminate 57.1%of TP、51.26%of particulate phosphorus、89.86%of chlorophyll-a and 65.17%of SS,also can improve water transparency.Artificial substrate could removed orthophosphate and various kinds forms of nitrogen,however,the differences was not significant.In nature water body, artificial substate can eliminate the various kinds of nitrogen,chlorophyll,SS and COD_Mn,but the effect is not significant,and all kinds of phosphorus concentration is higher than that of control.Through nutrient competition and allelopathy on phytoplankton growth,promotion of fish feces sedimentation and reducing of SS content,TP concentration in the water was reduced and water quality was improved by aitificial substate.In the non-tilapia water body,nutrients concentration was low and part of nutrients was eliminated by aritificial substrate,however,the effect was not significant.So results above showed that the effects of artificial substates was better in higher than in lower nutrient concentration water body.In the laboratory conditions,the study imitates how the exogenous nutrient(N:2 mg·L^-1·week^-1,P:0.1mg·L^-1·week^-1) influence nutrient circulation in the system of containing artificial adherences and snails.The result presented that periphyton could eliminate nutrients in water body effectively.,TP concentration and orthophosphate concentration reduced from about 0.4 mg·L^-1 and 0.036 mg·L^-1 At the beginning of this experiment to about 0.1 mg·L^-1 and 0.01 mg·L^-1 in the end,respectively;TN and ammonia nitrogen concentration reduced from about 4 mg·L^-1 and 2.3 mg·L^-1 to 1.2 mg·L^-1 and 0.4 mg·L^-1,respectively,and their removal rates were over 95%and 85%.Artificial substrate cart restrict phytoplankton growth and eliminate SS effectively,also can increase the saturation of DO and pH.Grazing effect of Bellamya sp. promoted circulation of nutrients,however,had little influence on periphyton community structure.更多还原