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滇池水体中微囊藻毒素含量变化与环境因子的相关性研究 总被引：23，自引：1，他引：23
本文对2003年4-12月滇池马村湾、海东湾微囊藻毒素和总磷、总氮、溶解氧、透明度、光照强度、叶绿素a、pH值、水温及微囊藻种群优势度进行了分析,讨论了以上指标在滇池马村湾和海东湾的分布和月变化情况以及与微囊藻毒素含量之间的关系．相关性分析表明马村湾、海东湾微囊藻毒素在水体中分布与总氮和氮磷比之间呈现非常显著的负相关性(P<0．01);与透明度、光照强度和微囊藻种群优势度存在显著的正相关性(P<0．05)．在影响微囊藻毒素的各因素中,运用多因素逐步回归分析得知马村湾、海东湾微囊藻毒素浓度主要南水体的总氮、总磷、叶绿素a和溶解氧以及透明度决定(R2=0．560,P<0．017)． 相似文献
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Lake Dianchi has undergone accelerated alternations resulting from human activities during the last 50 years, and provides an exceptional example for the study of regime shift in a shallow lake. Focusing on regime shift, we systematically studied and analysed alternations of key components of its ecosystem, including water parameters, phytoplankton and zooplankton biomass, macrophyte composition and fish populations. We found that the shifting course of Lake Dianchi went through three major phases, corresponding to three distinct states: Phase I clean, stable state during the 1950 s; Phase II transitional state during the 1970 s–1980 s; and phase III stable, turbid state since 1993. We analysed all data and samples, identifying the threshold concentrations at which regime shift occurred: total nitrogen(TN) and phosphorus(TP) reaching 1.2 mg/L and 0.13 mg/L, respectively. Results from this study strongly suggest that the increasing input of external nutrients, reclaiming land from the lake and foreign fish invasion were major inducements to the accelerated shift of Lake Dianchi to its turbid, stable state. These findings provide valuable guidelines for potential efforts to reverse this unnatural process in Lake Dianchi. The restoration may need to:(1) thoroughly and accurately identify pollution sources to control and reduce excessive external nutrients flowing into the lake;(2) return reclaimed land to the lake and recover the littoral zone to its natural state to facilitate increased restoration of macrophytes; and(3) strategically adjust fish populations by reducing benthivorous and filter-feeding fish populations that prey on zooplankton, while enlarging zooplankton populations to control phytoplankton biomass. 相似文献
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The aim of this study was to evaluate the physiological responses of a submerged macrophyte to a floating fi lamentous green algal bloom in clear-water conditions.Elodea nuttallii was grown with floating Cladophora sp.at four diff erent levels(0,control;140,280,560 g FW/m ~2)in an outdoor experimental system,and its photosynthetic and antioxidant systems were evaluated.The presence of floating Cladophora sp.signifi cantly changed the water environment by decreasing light intensity and increasing dissolved oxygen and the pH value.The photosynthetic parameters of E.nuttallii(e.g.?F/F _m~￠,F _v/F _m,total chlorophyll)were higher in the presence of floating Cladophora sp.than in the control at the beginning of experiment.Because of the increasing dissolved oxygen concentration and pH value,the values of these indicators decreased(except for photosynthetic pigments)during the experiment.Compared with E.nuttallii in the control,E.nuttallii growing in the presence of floating Cladophora sp.showed higher malondialdehyde content,catalase activity,and peroxidase activity.The biomass of E.nuttallii was decreased by about 30% in the presence of high biomasses of floating Cladophora sp.(280 and 560 g FW/m ~2).These results suggest that floating Cladophora had complex eff ects on the biomass of E.nuttallii and that changes in water quality resulting from floating Cladophora sp.may be more important than its direct shading eff ect. 相似文献
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In aquatic ecosystems, macrophytes and phytoplankton are main primary producers, in which macrophyte plays an important role
in maintaining clear water state, while phytoplankton often dominates in turbid waterbodies. In the present study, the growth
and photosynthetic activity of the submerged aquatic plant Ceratophyllum oryzetorum Kom. in different cell densities of cyanobacterial bloom are studied. The results show that the plant length and fresh mass
of C. oryzetorum are promoted by low cyanobacterial cell densities. Medium and high cyanobacterial cell densities, on the contrary, act as
inhibitory. Furthermore, the photosynthetic activity of C. oryzetorum is strongly inhibited by high cyanobacterial cell densities. To a certain extent, the growth of cyanobacteria is inhibited
by C. oryzetorum, but no significant effect is found in this study.
Supported by the Innovation Project of CAS (No.KZCX2-YW-426), a Provincial Project of Hubei (No. 2006AA305A0402) and the National
Basic Research Program of China (973 Program, No. 2002CB 412306) 相似文献
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Eutrophication has become a serious concern in many lakes, resulting in cyanobacterial blooms. However, the mechanism and pathways of cyanobacteria decline are less understood. To identify and define the growth and decline of Microcystis blooms in Taihu Lake of China, and to illuminate the destination of surface floating blooms, we investigated the biomass distribution and variations in colony size, morphology, and floating velocity from October 2008 to September 2009. The results showed that the Microcystis bloom declined in response to biomass decrease, colony disaggregation, buoyancy reduction, and increased phytoplankton biodiversity, and these indicative parameters could be applied for recognition of the development phases of the bloom. Three major decline pathways were proposed to describe the bloom decline process, colony disaggregation (Pathway Ⅰ), colony settlement (Pathway Ⅱ), and cell lysis in colonies (Pathway Ⅲ). We proposed a strategy to define the occurrence and decline of Microcystis blooms, to evaluate the survival state under different stress conditions, and to indicate the efficiency of controlling countermeasures against algal blooms. 相似文献
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In aquatic ecosystems, macrophytes and phytoplankton are main primary producers, in which macrophyte plays an important role in maintaining clear water state, while phytoplankton often dominates in turbid waterbodies. In the present study, the growth and photosynthetic activity of the submerged aquatic plant Ceratophyllum oryzetorum Kom. in different cell densities of cyanobacterial bloom are studied. The results show that the plant length and fresh mass of C. oryzetorum are promoted by low cyanobacterial cell densities. Medium and high cyanobacterial cell densities, on the contrary, act as inhibitory. Furthermore, the photosynthetic activity of C. oryzetorum is strongly inhibited by high cyanobacterial cell densities. To a certain extent, the growth of cyanobacteria is inhibited by C. oryzetorum, but no significant effect is found in this study. 相似文献
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选取生态系统中重要的组成成份:浮游植物、底栖动物、水生植物的历史演变和现在分布状况数据,结合水质变化情况,揭示了滇池生态系统退化原因:在外因上,污染物持续输入以及围湖造田、直立堤岸和水量交换缓慢等外力干扰加剧系统组分失衡是直接原因;在内因上,由于滇池所处的地理位置、气候等原因,蓝藻生物量对营养盐增加的响应远高于其他湖泊(太湖、巢湖),草型向藻型湖泊的转换进程更快;与太湖和东湖的生态系统比较,高原湖泊滇池生态系统相对脆弱,如物种的同域分化、窄生态位,导致系统的稳定性差、自我修复能力弱.通过对滇池生态格局特征、湖岸带结构的分析,将滇池划分为5个生态区:草海重污染区、藻类聚集区、沉水植被残存区、近岸带受损区和水生植被受损区,并提出"五区三步,南北并进,重点突破,治理与修复相结合"的滇池生态系统分区分步治理的新策略和"南部优先恢复;北部控藻治污;西部自然保护;东部外围突破"的总体方案. 相似文献
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作为主要的初级生产者,浮游植物在水生生态系统中扮演着重要的角色,浮游植物的时空分布反映了生态环境的变化.依据浮游植物的形态、生理、生态特点而定义的浮游藻类功能群对藻类的耐受性和敏感性进行了描述,因而浮游藻类功能群的组成是生境特征的良好指示者.对1960s至今抚仙湖、洱海、滇池3个高原湖泊的浮游藻类组成进行分析,并首次将功能群理论运用到这3个湖泊.结果表明,3个湖泊的浮游藻类优势功能群组成在近50～60年间发生了明显的改变:抚仙湖的浮游藻类优势功能群演变过程为C、X2、Lo、F、P(1960s)-H1、C、P(1980s)-P、C、T(1990s)-T(2000年以后);洱海的浮游藻类优势功能群演变过程为J、Lo、MP、C、H1(1960s)-C、H1(1980s)-C、H1(1990s)-C、H1、M(2000年以后);滇池的浮游藻类优势功能群演变过程为J、N、P、MP、Lo(1960s)-J、P、MP、M(1980s)-J、M(1990s)-M(2000年以后).抚仙湖、洱海、滇池水体内的藻类功能群演替趋势特征,即耐低温物种的减少以及喜营养物种的增加,表明3个高原湖泊在近几十年可能受到了气候变暖和营养程度增加的影响. 相似文献
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