1株微小杆菌对4种蓝藻的生长影响

利用过滤的天然珍珠养殖水参照BG11配制加富培养液,将1株能促进鱼害微囊藻生长的微小杆菌属菌株(Exiguobacterium sp.013,简写为E.sp.013)进行纯化扩大培养后与铜绿微囊藻(Microcystis aeruginosa)、水华微囊藻(Microcystis flosaquae)、平裂藻(Merismopedia sp.)和惠氏微囊藻(Microcystis wesenbergii)按一定菌、藻密度比例同时接种后进行为期24 d的培养试验,利用特定生长率和细胞密度等指标观察并检验E.sp.013菌株对4种蓝藻生长的影响,同时检测培养液中优势菌群的数量变化趋势.结果表明:E.sp.013菌对铜绿微囊藻、水华微囊藻和惠氏微囊藻具有显著促生长和延长稳定生长期作用,对平裂藻不具有显著促生长作用,但对延长其稳定生长期具有显著效果;试验培养过程中E.sp.013菌落数量占所有菌落总数的比例始终高于46％,处于绝对优势地位,表明E.sp.013菌具有调控其他菌群的能力.     

饮用水中蓝藻毒素污染研究进展

日趋严重的水体富营养化已成为全球性的环境问题，藻类及藻毒素给传统净水工艺带来了诸多不利影响，增加了水处理难度。对饮用水中蓝藻毒素去除技术进行了具体的论述，系统分析了各种技术的去除效果和局限性，并对藻毒素研究前景进行了展望。     

以再生水为补水的景观水体水华爆发特征调查和药剂应急控藻效果评价

采用现场调查和实验室验证的方法,对以再生水为景观补水的水华优势藻进行了分析。2年的现场调查表明,再生水在条件适合时极易发生水华,且水华的优势藻以小球藻为主。在实验室针对小球藻和铜绿微囊藻进行了竞争生长实验研究,在再生水的氮磷浓度范围内小球藻生长快于铜绿微囊藻,这也验证了再生水作为景观水补水时小球藻是优势藻现场调查结论。针对水华爆发初期和水华爆发验证时2种条件,比较研究了4种以化学成分为主的抑藻药剂对以小球藻为水华特征藻的控藻效果。结果表明,这4种药剂对水华的控制均具有一定的效果,并且水华初期实施药剂抑藻,药剂投加少,且效果好。对4种药剂进行急性毒性实验,只有S2一种药剂在安全浓度时对水华爆发初期有抑藻效果。     

基于BP人工神经网络和模糊理论的太湖蓝藻水华发生风险评价

目前,湖泊蓝藻水华是我国乃至世界的重大环境问题之一。蓝藻水华的暴发机制复杂,具有明显的不确定性。以太湖为例,根据近5 a水环境和水华发生的实测数据,结合BP（Back Propagation）人工神经网络和模糊理论,建立了蓝藻水华发生风险的模糊风险评价方法。对太湖9个水环境功能区的评价结果表明：西部沿岸区、梅梁湖蓝藻水华发生风险最大,为重度蓝藻水华风险区;竺山湖、五里湖次之,为中度蓝藻水华风险区;南部沿岸区、贡湖、湖心区为轻度蓝藻水华风险区,东太湖和东部沿岸区水华发生风险最小,为轻微蓝藻水华风险区。建立的评价方法和评价结果,可为蓝藻水华的预测、预警以及风险管理提供参考和依据。     

Structure-related distribution of PCDD/Fs, PCBs and HCB in a river-sea system

Water concentrations of PCDD/Fs, HCB, and non-ortho, mono-ortho, and non-dioxin-like PCBs were measured four times during 1 year in a coastal area of the Baltic Sea, to investigate background levels and distribution behaviour. Sampling sites included two rivers, an estuary, and the sea. Particulate and apparently dissolved concentrations were determined using active sampling (filters + PUFs), while freely dissolved concentrations were determined using passive sampling (POM-samplers). The distribution between particulate + colloidal and freely dissolved phases, in the form of TOC-normalized distribution ratios (K_TOC), was found to be near or at equilibrium. The observed K_TOC were not significantly different between sampling sites or seasons. For PCDD/Fs, the concentrations were significantly correlated to suspended particulate matter (SPM), while no correlation to organic carbon (TOC) was observed. In the estuary and the sea, PCB concentrations were correlated to TOC. The sorption of various congeners to SPM and TOC appeared to be related to both hydrophobicity and 3D-structure. The PCDD/F concentration in the sea decreased to one third in May, likely connected to the increased vertical flux of particles during the spring bloom.     

北京城市河湖营养状态与蓝藻水华研究

2003-2004年的调研结果显示,北京城市河湖(长河水系)总氮平均含量为1.667 mg/L,总磷平均含量为0.144 mg/L,浮游藻类平均细胞密度为41 150×104/L,其中蓝藻占90.0%.浮游藻类的群落结构为蓝藻(Cyanophyta)-绿藻(Chlorophyta)型,河湖水体中营养盐与初级生产力的关系为浮游藻类响应型,连续两年发生以微囊藻(Microcystis)占优势的蓝藻水华.河湖水体5项指标(SD、TP、TN、CODMn、Chla)的TSIM值在57～87间,水体已达到富营养或重富营养程度.其主要原因是:1)营养盐和有机物的污染;2)北京市淡水资源紧缺,补给城市河湖水量少;3)在河湖水系治理中,底部硬化,两侧(或周围)衬砌,破坏了水体的自然生态系统,使其自净能力大大降低.     

围隔中水华控制实验

目前我国很多湖泊和水库处于富营养化状态,其显著表现之一是微囊藻(Microcystis)在湖泊生态系统中恶性生长,形成水华,使水体群落结构恶化,湖泊水产品产量降低,湖泊丧失旅游价值,尤其严重的是影响了自来水厂的正常运行。 许多学者对控制微囊藻的生长进行过研究,其中最主要的方法是减少营养元素(主要是磷、氮进入湖泊的控制),对流域的点污染源和面污染源进行控制。这种方法耗资大,就我国的经济承受能力而言,短期内还很难全面实行。生物控制方法有引入微囊藻致病微生物或引入捕食微囊藻的浮游动物和鱼类,但目前仅处在实验室阶段。在以供水为主要功能的水体中,用化学方法控制微囊藻生长是使用比较广泛的方法。近年来,人们虽然试验了一万余种有机化合物的杀藻作用,但最常用的化学除藻剂仍是硫酸铜。这些除     

^15N isotope fractionation in an aquatic food chain： Bellamya aeruginosa （Reeve） as an algal control agent

15N isotope tracer techniques and ecological modeling were adopted to investigate the fractionation of nitrogen,its uptake and transformation in algae and snail(Bellamya aeruginosa Reeve).Different algal species were found to differ in their uptake of nitrogen isotopes.Microcystis aeruginisa Ktz.demonstrated the greatest 15N accumulation capacity,with the natural variation in isotopic ratio(δ 15N) and the isotope fractionation factor(ε,‰) being the highest among the species investigated.The transformation and utilization of 15N by snails differed depending on the specific algae consumed(highest for Chlorella pyrenoidosa Chick.,lowest for M.aeruginisa).When snails was seeded in the experimental pond,the algae population structure changed significantly,and total algal biomass as well as the concentration of all nitrogen species decreased,causing an increase in water transparency.A model,incorporating several chemical and biological parameters,was developed to predict algal biomass in an aquatic system when snails was present.The data collected during this investigation indicated that the gastropods such as snails could significantly impact biological community and water quality of small water bodies,suggesting a role for biological control of noxious algal blooms associated with eutrophication.     

Long-term joint e ect of nutrients and temperature increase on algal growth in Lake Taihu, China

To study how global warming and eutrophication a ect water ecosystems, a multiplicative growth Monod model, modified by incorporating the Arrhenius equation, was applied to Lake Taihu to quantitatively study the relationships between algal biomass and both nutrients and temperature using long-term data. To qualitatively assess which factor was a limitation of the improved model, temperature variables were calculated using annual mean air temperature (AT), water temperature (WT), and their average temperature (ST), while substrate variables were calculated using annual mean total nitrogen (TN), total phosphorus (TP), and their weighted aggregate (R), respectively. The nine fitted curves showed that TN and AT were two important factors influencing algal growth; AT limited growth as algal photosynthesis is mainly carried out near the water surface; N leakage of phytoplankton and internal phosphorus load from sediment explains why TN was the best predictor of peak biomass using the Monod model. The fitted results suggest that annual mean algal biomass increased by 0.145 times when annual mean AT increased by 1.0°C. Results also showed that the more eutrophic the lake, the greater the e ect AT had on algal growth. Subsequently, the long-term joint e ect of annual temperature increase and eutrophication to water ecosystems can be quantitatively assessed and predicted.     

基于MODIS数据的太湖蓝藻水华时空分布规律研究

利用EOS/MODIS遥感影像数据,采用蓝藻水华分级评价方法和蓝藻水华发生频率分析方法,对2010年～2013年不同级别太湖蓝藻水华时空分布规律进行分析和研究,以期为太湖蓝藻水华预警、监控、治理工作提供技术支持.结果表明：（1） 2010年～2013年,全太湖共发生蓝藻水华354次,其中小型水华发生次数最多,蓝藻水华级别越高,发生次数越少.（2）年际变化上,蓝藻水华发生次数总体趋于平稳,蓝藻水华发生呈现“小型多发、中大型少发、重大型偶发”趋势,蓝藻水华发生规模呈显著缩小趋势.（3）月际变化上,蓝藻水华主要发生在8 ～10月,8月和9月尤其是太湖蓝藻水华的高发月份.发生规模上,4～6月蓝藻水华发生规模较小,7月开始规模逐步扩大,到9月达到顶峰,10月规模有所缩小.（4）空间变化上,太湖西部沿岸是太湖蓝藻水华首次爆发最频繁的水域.从空间分布频率来看,太湖西部沿岸区尤其宜兴沿岸是蓝藻水华爆发频率最高的水域.