溶藻系统中微生物的群落结构研究

从藻类消退期的河流中取水样,分别加入斜生栅藻、铜绿微囊藻、小球藻、人工湖泊中的两种混合野生藻及氧化塘中的野生藻,平行培养1周,考察水样中的溶藻细菌对这些藻类的去除效果.结果表明,对上述水样中的叶绿素a的去除率分别为94.69%、95.41%、94.50%、89.19%、92.67%和95.63%.采用PCR-DGGE指纹分析技术初步研究了加入不同藻类水样的微生物群落结构,结果表明加入藻类的水样与原始水样的群落结构存在较大差异,但加入不同藻类的水样之间的相似度较高.溶藻系统中的微生物种类包括未培养的细菌类、Bacillus sp.、Bacillus cere-us、Stenotrophomonas sp.等.     

草履虫对铜绿微囊藻的吞噬能力研究

以草履虫为研究对象,通过显微染色跟踪观察了草履虫对铜绿微囊藻的吞噬过程,并通过草履虫与铜绿微囊藻的混合培养,研究了草履虫对铜绿微囊藻的吞噬能力.结果表明,混合培养系统中铜绿微囊藻的光密度值随着培养时间的延长而线性下降,且草履虫加入的数量越多,藻光密度下降的程度就越大;进一步分析表明,草履虫的除藻能力与草履虫投加密度呈对数关系,相关系数为0.957 4;当草履虫密度为30个/mL时,单位草履虫对铜绿微囊藻的吞噬能力最强,每天可以吞噬113个藻细胞,由此引起叶绿素的下降量为0.61μg.     

镉胁迫对两种海洋微藻生长和抗氧化系统的影响

采用实验生态学和生物化学的方法,研究了不同含量Cd(Ⅱ)(0.05、0.1、0.5、1.0 mmol/L)对两种海洋微藻的可溶性蛋白含量、超氧化物歧化酶(SOD)活性、过氧化氢(H2O2)、丙二醛(MDA)和还原型谷胱甘肽(GSH)含量的影响。结果表明:0.05 mmol/L的Cd(Ⅱ)对湛江等鞭金藻Isochrysis zhan-jiangensis的生长无明显影响,与对照组相比,可溶性蛋白含量略微增加,而高浓度(>0.05 mmol/L)的Cd(Ⅱ)对湛江等鞭金藻的生长有显著抑制作用,可溶性蛋白含量也迅速减少;普通小球藻Chlorella vul-garis的生长也明显受到Cd(Ⅱ)的抑制,可溶性蛋白含量减少。Cd(Ⅱ)胁迫抑制了两种藻类的SOD活性;随着Cd(Ⅱ)浓度增加,普通小球藻和湛江等鞭金藻的H2O2和MDA含量升高,普通小球藻的GSH含量升高,而湛江等鞭金藻的GSH含量在低浓度Cd(Ⅱ)胁迫下有所升高,高浓度时则下降。Cd(Ⅱ)胁迫对普通小球藻和湛江等鞭金藻的生长和抗氧化系统都产生了一定程度的影响。     

不同食物对透明溞种群生长的影响

在实验室恒定温度(20℃)条件下,比较分析了以不同藻类(小球藻、柱孢鱼腥藻170、铜绿微囊藻469和铜绿微囊藻905)为基础饵料的透明溞Daphnia hyaline种群的生长繁殖情况。结果表明:以小球藻为饵料的透明溞种群数量快速增加,最大种群密度为(211.22±7.22)ind./L,以铜绿微囊藻469为饵料的透明溞最大种群密度为(133.75±4.84)ind./L,为小球藻组的1/2,而以鱼腥藻170和铜绿微囊藻905为饵料的透明溞最大种群数量较少,分别为(70.00±5.69)、(50.75±4.38)ind./L。用Logistic曲线拟合的结果表明,小球藻组和铜绿微囊藻469组的拟合效果较好,拟合度分别为0.989和0.988。以小球藻、铜绿微囊藻469、铜绿微囊藻905和柱孢鱼腥藻170为饵料的4组透明溞最大种群增长速率(rmax)分别为1.468、1.030、0.424、0.405 ind./d,4组透明溞的种群数量增长模型分别为N=27.689/[1+e20.141-0.212t](R2=0.989)、N=15.094/[1+e17.659-0.273t](R2=0.988)、N=17.124/[1+e33.769-0.099t](R2=0.909)和N=11.202/[1+e20.988-0.145t](R2=0.953)。研究表明,投喂小球藻对透明溞种群生长有明显的促进作用,而投喂有毒的铜绿微囊藻905和柱孢鱼腥藻170对透明溞的生长与繁殖均有抑制作用。     

预氯化处理高藻原水的特性分析

对某水厂预氯化前后水样中藻类种类和数量进行了分析,结果表明,预氯化对不同种藻类有不同程度的去除.预氯化对不对称衣藻、水生集胞藻和微小平裂藻的去除率较高,而对厚变浮游角星鼓藻和水华微囊藻去除率较低.这主要取决于氯的氧化性和藻类形态结构.预氯化对叶绿素a有较高的去除率,同时可降低原水中氨氮含量和高锰酸盐指数.     

氨基酸对铜绿微囊藻生长及叶绿素荧光参数的影响

为研究氨基酸对铜绿微囊藻Microcystis aeruginosa生长及叶绿素荧光参数的影响,设定藻的初始密度为2×10⁶ cells/mL,以6种氨基酸(天门冬氨酸、丝氨酸、精氨酸、谷氨酸、丙氨酸和甘氨酸)为唯一氮源,分析在实验室模拟自然水体不同氨基酸浓度(12、25、50、75、100μmol/L)条件下,铜绿微囊藻细胞数量、叶绿素a含量及相关叶绿素荧光参数(F_v/F_m、ETR)的动态变化。结果表明:无氮对照组的藻细胞数量、叶绿素a含量及相关叶绿素荧光参数均显著低于各氨基酸试验组(P<0.05);随着氨基酸浓度的升高,6种氨基酸均能促进铜绿微囊藻的生长及相关叶绿素荧光参数的提高,且多种氨基酸在浓度为100μmol/L时达到最高值;随着培养时间的延长,除谷氨酸试验组各项指标波动明显外,其余各氨基酸试验组的藻细胞数量、叶绿素a含量及相关叶绿素荧光参数总体上均呈先上升后下降趋势,其结果基本符合藻细胞延滞期、对数生长期、稳定期的规律。研究表明,不同浓度和不同种类的氨基酸对铜绿微囊藻生长及叶绿素荧光参数提高均表现出有利特征,且氨基酸的作用程度依次为天门冬氨酸>丝氨酸>精氨酸>丙氨酸>谷氨酸>甘氨酸,本研究结果可为揭示自然水体中氨基酸对铜绿微囊藻的影响机制提供数据参考。     

浮游式太阳能超声波除藻装置的构建及其效能研究

利用超声波和太阳能构建浮游于水体表面的超声波除藻装置,用于去除水体中的藻类,以解决富营养化水体的蓝藻水华问题。因此研究了该装置即时去除和持续性抑藻效果,以及对实际水体的除藻效果。结果表明:浮游式太阳能超声波除藻装置能有效去除与抑制藻类的生长,对常见蓝藻-铜绿微囊藻的最大即时去除率为40%,且能长期抑制藻细胞的分裂增殖速率;超声波除藻装置能有效去除自然水体中的藻类,作用时间越长,除藻效果越好,处理60 min后藻类的去除率可达80%以上。因此,该装置可用于去除富营养化水体的蓝藻,并且具有良好的应用前景。     

9种黏土对铜绿微囊藻的去除效果

对比了9种黏土对铜绿微囊藻的絮凝去除效果,并通过对铜绿微囊藻、黏土以及藻絮体的扫描电镜观察,分析了黏土对铜绿微囊藻的网捕作用,同时探讨了黏土的固有理化性质对去除铜绿微囊藻的影响。结果表明,黏土种类对铜绿微囊藻的去除有较大影响,当黏土浓度为0.6 g/L时,烂黄泥土的去除效果最好,其对叶绿素a的去除率达到了98.75%。黏土的Zeta电位、有机质含量、铁+铝含量与铜绿微囊藻去除率呈线性正相关关系,相关性强弱顺序为Zeta电位有机质含量铁+铝含量。     

ΔDO单一指标评价景观水体富营养化的研究

提出了采用水中溶解氧昼夜浓度最大差值(ΔDO)单一指标来及时评价景观水体富营养化程度的方法。在光暗比为1∶1、温度为25℃、光照强度为2 000 lx条件下,通过测定不同纯藻的光合产氧速率和叶绿素a(Chl-a)浓度,以及实际混合藻群的DO、ΔDO和Chl-a浓度,建立了不同藻种及混合藻群ΔDO与Chl-a浓度的关系,探讨了采用ΔDO单因素评价景观水体富营养化程度的可能性。结果表明,在含铜绿微囊藻、小球藻、伪鱼腥藻、混合藻群的实际景观水体中,ΔDO与Chl-a浓度的Pearson相关系数分别为0. 95、0. 96、0. 97和0. 93,相关性显著。因此,采用ΔDO作为富营养化程度单因素评价指标有一定的可行性。此外,还确定了不同ΔDO对应的水体富营养化程度范围,可为景观水体富营养化程度评价提供有效、快捷的方法。     

生物制剂H对水华优势藻的生长抑制作用

生物制剂H是新开发的一种抑制藻类生长的药剂,对应用该生物制剂控制景观水体水华优势藻种--铜绿微囊藻和小球藻的效果及生态安全性进行了研究.结果表明,在铜绿微囊藻初始密度为10^8 cell/L数量级时投加1～15 mg/L的生物制剂H具有很好的生长抑制作用,且优于在初始藻密度为10^9 cell/L数量级时加药的效果;在小球藻初始密度为10^8 cell/L数量级时投加5～15 mg/L的生物制剂H具有较好的生长抑制作用.对加药前后小球藻的扫描电镜（SEM）观察结果显示,加药后其细胞结构发生了破坏性改变.对青鳉鱼的急性毒性试验结果表明,生物制剂H具有良好的生态安全性,其48 h半致死浓度为934.5 mg/L,96 h半致死浓度为718.8 mg/L,安全浓度为93.5 mg/L.     

Characterisation of algogenic organic matter extracted from cyanobacteria, green algae and diatoms

Algogenic organic matter (AOM) can interfere with drinking water treatment processes and comprehensive characterisation of AOM will be informative with respect to treatability. This paper characterises the AOM originating from four algae species (Chlorella vulgaris, Microcystis aeruginosa, Asterionella formosa and Melosira sp.) using techniques including dissolved organic carbon (DOC), specific UV absorbance (SUVA), zeta potential, charge density, hydrophobicity, protein and carbohydrate content, molecular weight and fluorescence. All AOM was predominantly hydrophilic with a low SUVA. AOM had negative zeta potential values in the range pH 2-10. The stationary phase charge density of AOM from C. vulgaris was greatest at 3.2 meq g(-1) while that of M. aeruginosa and Melosira sp. was negligible. Lower charge density was related to higher hydrophobicity, while it was related in turn to increasing proteins >500 kDa:carbohydrate ratio. This demonstrates that AOM is of a very different character to natural organic matter (NOM).     

Differential sensitivity of three cyanobacterial and five green algal species to organotins and pyrethroids pesticides

In this work, five organotins and pyrethroids pesticides were tested to examine their effects on the three cyanobacteria Anabaena flos-aquae, Microcystis flos-aquae, Mirocystis aeruginosa and on the five green algae Selenastrum capricornutun, Scenedesmus quadricauda, Scenedesmus obliqnus, Chlorella vulgaris, Chlorella pyrenoidosa through 96 h acute toxicity tests. The results indicated that: (1) the decreasing order of the average acute toxicity to cyanobacteria and green algae of five dissimilar organotins and pyrethroids pesticides was: fentin hydroxide > cyhexatin > azocyclotin > fenbutatin oxide > beta-cyfluthrin. (2) Wide variations occurred in response to the tested pesticides among the eight individual species of cyanobacteria and green algae. The sensitivity of various species of algae exposed to fenbutatin-oxide varied over one order of magnitude, exposed to cyhexatin/fentin-hydroxide/beta-cyfluthrin varied over two orders of magnitude and exposed to azocyclotin varied three orders of magnitude. (3) In contrast with the sensitivity of cyanobacteria and green algae, cyanobacteria were much less sensitive to beta-cyfluthrin than green algae. The pollutants may result in a shift of green algal and cyanobacterial group structure, especially in a shift from dominance by green algae to dominance by cyanobacteria, and may sustain cyanobcterial blooms during the special period. Thus, the decreasing order of the aquatic ecological risk was: beta-cyfluthrin > fentin hydroxide > cyhexatin > azocyclotin > fenbutatin oxide. There was a strong variance between toxicity and ecological risk, i.e. "low toxicity" does not automatically imply "low ecological risk". The toxicity of pyrethroids pesticides was lower than that of organotins pesticides, whereas the aquatic ecological risk of pyrethroids pesticides was higher than that of organotins pesticides.     

Effects of submerged macrophytes on sediment resuspension and internal phosphorus loading in Lake Hiidenvesi (southern Finland)

The effects of submerged macrophytes on sediment resuspension and internal phosphorus loading in the shallow Kirkkoj?rvi basin of Lake Hiidenvesi were studied by sedimentation traps and sediment and water samples. During the 83 d study period, 793 g DW m(-2) of sediment was resuspended within the stand formed by Ranunculus circinatus, Ceratophyllum demersum and Potamogeton obtusifolius. Outside the stand, 1701g DW m(-2) sediment resuspension was measured during the same period. Water turbidity and concentration of suspended solids (SS) were significantly lower within the plant bed compared with the surrounding water area. Despite the higher concentration of inorganic suspendoids, the concentration of chlorophyll a was higher in the open water than within the submerged plant bed, owing to the enhanced nutrient recycling rate in the absence of submerged plants. With the resuspended sediment, 11.8 mg Pm(-2)d(-1) was brought into the water column within the stand and 24.5 mg Pm(-2)d(-1) outside the stand. Within the macrophyte stand, resuspended particles absorbed phosphorus from the water (indicated by the inverse relationship between SS and soluble reactive phosphorus), which was probably connected to the lowered phosphorus concentration of surface sediment due to uptake by macrophytes.     

The impact of differing cell and algogenic organic matter (AOM) characteristics on the coagulation and flotation of algae

The aim of this study was to compare the coagulation and flotation of different algae species with varying morphology and algogenic organic matter (AOM) composition in order to link physical and chemical algae characteristics to treatment. Microcystis aeruginosa (cyanobacteria), Chlorella vulgaris (green algae), Asterionella formosa and Melosira sp. (diatoms) were treated by coagulation with aluminium sulphate and flotation. The AOM was extracted and treated separately. Analyses included cell counts, dissolved organic carbon, aluminium residual and zeta potential. Removal efficiencies in the range 94-99% were obtained for each species. Cells, AOM and aluminium were concurrently removed at a coagulant dose that was related on a log-log basis to both cell surface area and total charge density, although the relationship was much stronger for the latter. This was attributed to a significant proportion of the coagulant demand being generated by the AOM. The implications of such findings are that relatively simple charge measurements can be used to understand and control coagulation and flotation of algae.     

水源水库中藻类生长及分布特征

对西安市地表水源水中的藻类进行了监测,结果表明,2007年3-5月藻种主要为绿藻、硅藻,其优势种属分别为星球藻、直链藻,含藻量峰值出现在5月底,细胞密度为2 254 × 104个/L:6-9月藻种主要为蓝藻、绿藻,其优势种分别为微囊藻、栅列藻,含藻量峰值出现在7月中旬,细胞密度为3 009×104个/L.监测期间水源水的总氮平均含量为1.54 mg/L,总磷平均含量为0.015 mg/L,N/P较高,表现为氮过量,磷为限制因子.藻种群密度高峰值主要受磷含量、水温及光照的影响.黑河库区水体已为中营养状态,并出现了富营养型浮游植物指示种类,水体向富营养化发展趋势明显.     

太湖芦苇根系中溶藻菌的分离鉴定及溶藻效果

富含氮、磷、钾等营养物质的污水排入河流、湖泊,造成蓝藻爆发,而溶藻菌可以有效降解水体中的蓝藻污染。从蓝藻污染严重的太湖百渎港岸边芦苇根系中筛选出1株溶藻菌(Bacillus sp),命名为G6,系统发育分析表明,G6菌株与芽孢杆菌同源性最高。将培养至对数期的G6菌液以菌藻比1∶10的比例,在温度28℃、光强2 500lx、光暗比12h∶12h的条件下经光照培养箱培养7d,对铜绿囊藻液Chla去除率可达82%。此外,G6菌株在无光照条件下也具有溶藻特性,这有利于其在缺少光照的深水域中增殖并发挥溶藻作用。G6通过分泌溶藻物质杀灭铜绿囊藻,属于间接溶藻,且溶藻物质具有热稳定性,能够在较高温度下发挥溶藻特性。     

Preparation of free‐standing chitosan membranes for Chlorella vulgaris harvest and examination on suppression of algae‐fouling properties

Free‐standing chitosan membranes were prepared using genipin as crosslinker, using several molecular weights of polyethylene glycol (PEG) as a void‐forming agent. The membrane surface formation and chitosan polymer chain crosslinking were confirmed through SEM and FTIR, respectively. The water flux was remarkably increased with increasing molecular weight of PEG employed in preparation of composite chitosan membrane (J∝[PEG(MW)]0.85), it appeared over 6000 Da of PEG. During Chlorella vulgaris harvest using chitosan membranes, focus was made on algae‐fouling caused by the deposition of cells and extracellular organic matter, and it was found that membranes employing lower molecular weight of PEG (under 10000 Da) had been maintaining the high flux recovery after alternating filtration cycles, in addition to PEG20000 containing membrane. The chitosan membrane prepared with lower molecular weight of PEG exhibited better suppression of algae‐fouling properties. The Chlorella vulgaris harvesting results indicated that cell rejection rate reached above 98%.     

掺硼金刚石薄膜电极电化学氧化对铜绿微囊藻的生长抑制

阳极材料采用掺硼金刚石薄膜板状电极,研究了电化学氧化中电流密度、电解时间、pH、氯离子浓度、硫酸根离子浓度对铜绿微囊藻生长抑制的影响,以及电解前后藻细胞形态的变化。结果表明,4个影响因素对铜绿微囊藻生长抑制效果显著。抑藻效果随电流密度、电解时间的增加而增加,电流密度为17mA/cm2时藻细胞出现破裂、细胞内物质流出的现象,抑藻效果较好;当电解时间为20min时,可完全抑制藻细胞生长;再增大电解时间,对抑藻效果无明显促进作用,初始pH在中性及酸性条件下可完全抑制藻细胞生长。抑藻效果与溶液中氯离子、硫酸根离子浓度成正相关,当溶液中氯离子浓度为6mg/L时,可完全抑制藻细胞生长;无氯离子时,藻细胞在4d后出现继续增长现象。