Numerical models for management of <Emphasis Type="BoldItalic">Anabaena circinalis</Emphasis>

The control of nuisance species of cyanobacteria in reservoirs is a critical issue for the international water industry, as these organisms can produce toxins and compounds that taint potable water with unpleasant tastes and odours. To assist with effective management of cyanobacterial growth, numerical models that are either site specific or universally applicable can be employed. An artificially destratified reservoir was modelled with the coupled hydrodynamic-ecological numerical model DYRESM-CAEDYM. The validation site was Myponga Reservoir, South Australia, a highly managed drinking water supply reservoir. Chemical dosing (CuSO₄) and artificial mixing via an aerator and two raft-mounted mechanical surface mixers (hereafter referred to as surface mixers) are used at Myponga to manage the growth of the scum-forming cyanobacterium Anabaena circinalis. The dominant phytoplankton community was adequately modelled, and combinations of the various management options were simulated whereupon informed operational strategies could be implemented. Without any intervention, permanent stratification would occur and the growth of Anabaena circinalis would peak above 3 μ g L⁻¹, producing geosmin that would exceed the taste and odour threshold (10 ng L⁻¹); with the individual use of the aerator or surface mixers, growth of Anabaena circinalis was significantly reduced to below 1 μ g L⁻¹.     

洋河水库浮游植物组成及优势种演替规律研究

在洋河水库设置6个采样点, 对浮游植物进行了周年研究, 并在夏季进行了每周一次的加密采样, 以揭示水华期间藻类优势种演替规律。结果表明洋河水库全年共检测到浮游植物8门41属49种, 群落季节变化与温度密切相关。春季隐藻门的啮齿隐藻(Cryptomonas erosa)为优势, 夏季初期表层水温在25℃以下时, 绿藻门的波吉卵囊藻(Oocystis borgei)占主要优势; 当表层水温升至25℃以上, 微囊藻(Microcystis spp.)迅速取代其成为绝对优势。秋季硅藻门的克洛脆杆藻(Fragiaria crotomensis)和隐藻门的啮齿隐藻(C. erosa)为优势。空间分布上水库北部浅水区域隐藻和硅藻生物量普遍高于南部; 受东南风影响, 蓝藻生物量在西洋河口S2点位最大。CCA分析表明夏季水华主体微囊藻的生物量与氮浓度正相关, 螺旋鱼腥藻在夏季仅作为第二优势种短暂出现于西洋河口处, 其出现与否受到磷营养盐的限制。       

Comparative analysis of cyanobacterial communities from polluted reservoirs in Korea

Cyanobacteria are the dominant phototrophic bacteria in water environments. Here, the diversity of cyanobacteria in seven Korean reservoir waters where different levels of algal blooms were observed during the summer of 2002, was examined by T-RFLP analysis. The number of T-RF bands in the HaeIII T-RFLP profiles analyzed from those water samples ranged from 20 to 44. Of these, cyanobacteria accounted for 6.1 to 27.2% of the total bacteria. The water samples could be clustered into 2 groups according to the Dice coefficient of the T-RF profiles. The eutrophic Dunpo and oligotrophic Chungju reservoirs were selected, and several representative clones from both reservoir waters analyzed for the nucleotide sequences of their 16S rDNA. The major clones were found to belong to the Microcystis and Anabaena species in the waters from the Dunpo and Chungju reservoirs, respectively, which was in agreement with the T-RFLP result. That is, the Microcystis and Anabaena species were dominant in the eutrophic and polluted Dunpo and oligotrophic Chungju reservoir waters, respectively. These results indicated that there is a correlation between prevalence of cyanobacterial species and levels of pollution in reservoir waters.     

Seasonal variation of cyanobacteria and microcystins in the Nui Coc Reservoir, Northern Vietnam

In order to understand the environmental variables which promote the proliferation of cyanobacteria and variation in microcystin concentrations in the Nui Coc reservoir, Vietnam, physicochemical parameters, the occurrence, and abundance of phytoplankton, cyanobacteria, and microcystin concentration were monitored monthly through the year 2009–2010. The relationships between these parameters were explored using principal component analysis (PCA) and Pearson correlation analysis. The phytoplankton community was mainly dominated by the cyanobacterium Microcystis with higher cyanobacteria abundance during summer and autumn season. PCA and Pearson correlation results showed that water temperature and phosphate concentration were the most important variables accounting for cyanobacteria, Microcystis, and microcystin occurrence. Analysis of the toxins by high-performance liquid chromatography demonstrated the presence of two microcystin variants: microcystin-LR (MC-RR) and microcystin-ddRR (MC-ddRR) with total concentrations of the toxins in filtered samples from surface water ranging from 0.11 to 1.52 μg MC-LR equiv L^?1. The high concentrations of microcystin in the Nui Coc reservoir highlighted the potential risk for human health in the basin. Our study underlined the need for regular monitoring of cyanobacteria and toxins in lakes and reservoirs, which are used for drinking water supplies, not only in Vietnam but also in tropical countries.     

Investigation of microcystin removal from eutrophic surface water by aquatic vegetable bed

In southern China, many freshwater ecosystems, including lakes, rivers and reservoirs, are eutrophic. The nutrient loading coupled with year-round warm weather favors the growth of cyanobacteria, several of which can produce cyanotoxins, especially the potent liver toxins called microcystins, which are often detected in eutrophic drinking water sources. For purifying raw water used as source of drinking water treatment plants, an aquatic vegetable bed (AVB) experiment had been carried out in a hypertrophic waterfront of Lake Taihu, China, since October 2002. AVB was a simplification of the nutrient film technique (NFT) used to produce vegetables, which requires large quantities of water and nutrients. The average removal rates of total microcystin-RR and microcystin-LR were 63.0% and 66.7%, respectively. This study indicated that Ipomoea aquatica was able to absorb microcystins by using enzyme-linked immunosorbent assay (ELISA), and that the roots absorbed more toxins than leaves and stems. We used fluorescence in situ hybridization (FISH) to analyze the density of microcystin-degrading bacteria in AVB sediment. Two species of microcystin-degrading bacteria were detected, which indicated that microcystin bio-degradation processes did occur in AVB. Protozoa and metazoa were abundant in the rhizosphere. Aspidisca sp., Vorticella sp., Philodina sp., and Lecane sp. were the dominant species. The predation function of protozoa and metazoa had a positive effect on removal of cyanobacteria and microcystins.     

Microbial community study in newly established Qingcaosha Reservoir of Shanghai,China

Qingcaosha Reservoir located at Yangtze Estuary of China is a newly constructed and one of the largest tidal reservoirs in the world, which will be an important drinking water source of Shanghai. This study aims at investigating microbial community and its shifts corresponding to different water quality during the test running period of Qingcaosha Reservoir. The results showed lower concentrations of total nitrogen (TN) and total phosphorus (TP) in the reservoir than that in Yangtze Estuary. The number of total cultivable bacteria was significantly lower in the reservoir than that of Yangtze Estuary. The denaturing gradient gel electrophoresis (DGGE) analysis showed that the dominant microbes were α-Proteobacteria, β-Proteobacteria, Flavobacterium, Rheinheimera, Prochlorococcus, and Synechococcus. The quantitative PCR (q-PCR) results revealed significantly higher number of cyanobacteria and Microcystis in the reservoir during summer season. In addition, bacterial abundance positively correlated with TP concentration inside the reservoir. These results indicated that Qingcaosha Reservoir had ability to reduce the TN and TP in influent and improve the water quality overall. However, it also faced the risk of potential cyanobacteria bloom and eutrophication in Qingcaosha Reservoir where phosphorus will be the nutrient limiting factor.     

四川丘陵区水库浮游植物群落结构与蓝藻水华风险——基于优势种生态位与种间联结研究

为了解四川丘陵区中小型水库浮游植物群落结构周年变化,掌握其演替规律并预测其发展方向,于2016年-2017年分季节对该地区10个典型水库进行了周年研究。结果显示：共检出浮游植物9门104属188种,其中优势种4门16属16种,以湖泊假鱼腥藻（Pseudanabaena linmnetica）优势度指数为最高;蓝藻密度在各季节、各水库中均占据优势,尤其是夏季。优势种生态位宽度和生态位重叠度在存在明显的季节差异性,并受到水温、营养条件等环境因子的显著影响;优势种可分为3个类别,竞争力相对较强的7个种中有5种蓝藻;全年发展性最强的种类也多为蓝藻,特别是湖泊假鱼腥藻等具有产毒潜力的种类,其优势度存在进一步扩大的风险。种间联结性检验结果显示,群落种间大致表现出净的正联结,优势种种对间正负关联比大于1,该类水库群落结构较为稳定且存在正向演替的趋势,可能会导致夏季间断性产毒蓝藻水华的风险。研究结果可为四川丘陵区中小型水库浮游植物群落演替研究以及蓝藻水华预警提供基础资料。     

黄土高原不同侵蚀类型区生物结皮中蓝藻的多样性

蓝藻是生物土壤结皮的重要组成部分,具有许多重要的生态功能.迄今为止,黄土高原地区生物结皮中藻类的种类组成及分布鲜有报道.通过野外调查、采样和室内观察、培养、鉴定,对黄土高原水蚀区、水蚀风蚀交错区、风蚀区的生物结皮中蓝藻的多样性及优势种进行了研究.结果表明,黄土高原3个侵蚀类型区生物结皮中蓝藻门植物共发现4科10属54种,其中丝状种类约占87％,占绝对优势;Shannon-Weiner多样性指数水蚀风蚀交错区最高,水蚀区次之,风蚀区最低,依次为2.22,2.20和2.14.水蚀风蚀交错区和水蚀区蓝藻多样性指数差异不显著,但均与风蚀区差异显著.3个侵蚀类型区的生物结皮中蓝藻的种类组成及优势种均有所差异,但均以颤藻科(Oscillatoriaceae)为优势科.水蚀风蚀交错区蓝藻种类最多(39种),以阿氏鞘丝藻(Lyngbya allorgei)为第一优势种;水蚀区次之(26种),以含钙席藻(Phormidum calciola)为第一优势种;风蚀区最少(20种),以颗粒颤藻(Oscillatoria granulata)为第一优势种.黄土高原不同侵蚀类型区生物结皮中蓝藻的多样性差异可能与土壤质地、土壤pH值、气候环境等有关.     

Long-Term Patterns in the Population Dynamics of Daphnia longispina,Leptodora kindtii and Cyanobacteria in a Shallow Reservoir: A Self-Organising Map (SOM) Approach

The recognition of long-term patterns in the seasonal dynamics of Daphnia longispina, Leptodora kindtii and cyanobacteria is dependent upon their interactions, the water temperature and the hydrological conditions, which were all investigated between 1999 and 2008 in the lowland Sulejow Reservoir. The biomass of cyanobacteria, densities of D. longispina and L. kindtii, concentration of chlorophyll a and water temperature were assessed weekly from April to October at three sampling stations along the longitudinal reservoir axis. The retention time was calculated using data on the actual water inflow and reservoir volume. A self-organising map (SOM) was used due to high interannual variability in the studied parameters and their often non-linear relationships. Classification of the SOM output neurons into three clusters that grouped the sampling terms with similar biotic states allowed identification of the crucial abiotic factors responsible for the seasonal sequence of events: cluster CL-ExSp (extreme/spring) corresponded to hydrologically unstable cold periods (mostly spring) with extreme values and highly variable abiotic factors, which made abiotic control of the biota dominant; cluster CL-StSm (stable/summer) was associated with ordinary late spring and summer and was characterised by stable non-extreme abiotic conditions, which made biotic interactions more important; and the cluster CL-ExSm (extreme/summer), was associated with late spring/summer and characterised by thermal or hydrological extremes, which weakened the role of biotic factors. The significance of the differences between the SOM sub-clusters was verified by Kruskal-Wallis and post-hoc Dunn tests. The importance of the temperature and hydrological regimes as the key plankton-regulating factors in the dam reservoir, as shown by the SOM, was confirmed by the results of canonical correlation analyses (CCA) of each cluster. The demonstrated significance of hydrology in seasonal plankton dynamics complements the widely accepted pattern proposed by the plankton succession model for lakes, the PEG (Plankton Ecology Group), and may be useful for the formulation of management decisions in dam reservoirs.     

我国饮用水源水库微生物多样性研究述评

水源水库的水环境质量和生态安全世人瞩目,微生物在饮用水源水库生态系统的物质循环、能量流动和信息联系中发挥着重要作用,同时其丰度和多样性也是水环境质量监测的重要指标。综述了我国饮用水源水库微生物的作用、丰度、多样性等研究概况,并对水源水库微生物监测方法、蓝细菌分类和毒素特点及未来研究方向进行了讨论。     

Targeted deep sequencing reveals high diversity and variable dominance of bloom-forming cyanobacteria in eutrophic lakes

Cyanobacterial blooms in eutrophic lakes are severe environmental problems worldwide. To characterize the spatiotemporal heterogeneity of cyanobacterial blooms, a high-throughput method is necessary for the specific detection of cyanobacteria. In this study, the cyanobacterial composition of three eutrophic waters in China (Taihu Lake, Dongqian Lake, and Dongzhen Reservoir) was determined by pyrosequencing the cpcBA intergenic spacer (cpcBA-IGS) of cyanobacteria. A total of 2585 OTUs were obtained from the normalized cpcBA-IGS sequence dataset at a distance of 0.05. The 238 most abundant OTUs contained 92% of the total sequences and were classified into six cyanobacterial groups. The water samples of Taihu Lake were dominated by Microcystis, mixed Nostocales species, Synechococcus, and unclassified cyanobacteria. Besides, all the samples from Taihu Lake were clustered together in the dendrogram based on shared abundant OTUs. The cyanobacterial diversity in Dongqian Lake was dramatically decreased after sediment dredging and Synechococcus became exclusively dominant in this lake. The genus Synechococcus was also dominant in the surface water of Dongzhen Reservoir, while phylogenetically diverse cyanobacteria coexisted at a depth of 10 m in this reservoir. In summary, targeted deep sequencing based on cpcBA-IGS revealed a large diversity of bloom-forming cyanobacteria in eutrophic lakes and spatiotemporal changes in the composition of cyanobacterial communities. The genus Microcystis was the most abundant bloom-forming cyanobacteria in eutrophic lakes, while Synechococcus could be exclusively dominant under appropriate environmental conditions.     

Sediment Enzyme Activities and Microbial Community Diversity in an Oligotrophic Drinking Water Reservoir,Eastern China

Drinking water reservoir plays a vital role in the security of urban water supply, yet little is known about microbial community diversity harbored in the sediment of this oligotrophic freshwater environmental ecosystem. In the present study, integrating community level physiological profiles (CLPPs), nested polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) and clone sequence technologies, we examined the sediment urease and protease activities, bacterial community functional diversity, genetic diversity of bacterial and fungal communities in sediments from six sampling sites of Zhou cun drinking water reservoir, eastern China. The results showed that sediment urease activity was markedly distinct along the sites, ranged from 2.48 to 11.81 mg NH₃-N/(g·24h). The highest average well color development (AWCD) was found in site C, indicating the highest metabolic activity of heterotrophic bacterial community. Principal component analysis (PCA) revealed tremendous differences in the functional (metabolic) diversity patterns of the sediment bacterial communities from different sites. Meanwhile, DGGE fingerprints also indicated spatial changes of genetic diversity of sediment bacterial and fungal communities. The sequence BLAST analysis of all the sediment samples found that Comamonas sp. was the dominant bacterial species harbored in site A. Alternaria alternate, Allomyces macrogynus and Rhizophydium sp. were most commonly detected fungal species in sediments of the Zhou cun drinking water reservoir. The results from this work provide new insights about the heterogeneity of sediment microbial community metabolic activity and genetic diversity in the oligotrophic drinking water reservoir.     

The Tracing of Mycobacteria in Drinking Water Supply Systems by Culture, Conventional, and Real Time PCRs

Mycobacteria are widely present in diverse aquatic habitats, where they can survive for months or years while some species can even proliferate. The resistance of different mycobacterial species to disinfection methods like chlorination or ozonation could result in their presence in the final tap water of consumers. In this study, the culture method, Mycobacterium tuberculosis complex conventional duplex PCR for detection of non-tuberculous mycobacteria (NTM) and quantitative real-time PCR (qPCR) to detect three subspecies of M. avium species (M. a. avium, M. a. hominissuis, and M. a. paratuberculosis) were used to trace their possible path of transmission from the watershed through the reservoir and drinking water plant to raw drinking water and finally to households. A total of 124 samples from four drinking water supply systems in the Czech Republic, 52 dam sediments, 34 water treatment plant sludge samples, and 38 tap water household sediments, were analyzed. NTM of 11 different species were isolated by culture from 42 (33.9 %) samples; the most prevalent were M. gordonae (16.7 %), M. triplex (14.3 %), M. lentiflavum (9.5 %), M. a. avium (7.1 %), M. montefiorenase (7.1 %), and M. nonchromogenicum (7.1 %). NTM DNA was detected in 92 (76.7 %) samples. By qPCR analysis a statistically significant decrease (P < 0.01) was observed along the route from the reservoir (dam sediments), through water treatment sludge and finally to household sediments. The concentrations ranged from 10⁰ to 10⁴ DNA cells/g. It was confirmed that drinking water supply systems (watershed–reservoir–drinking water treatment plant–household) might be a potential transmission route for mycobacteria.     

Characterization of Aeromonas and Vibrio species isolated from a drinking water reservoir

AIMS: To study the phenotypic and chemotaxonomic (i.e. phospholipid and cellular fatty acid composition) characteristics of environmental Aeromonas spp. and Vibrio spp. isolated from a drinking water reservoir near Vladivostok City, and the application of some chemotaxonomic markers for discrimination of the two genera and species. METHODS AND RESULTS: Presumptive Aeromonas species were dominant in surface water samples (up to 25% of the total number of bacteria recovered). These strains were consistent with respect to the cultural and biochemical properties used to define the species Aeromonas sobria (seven strains) and Aer. popoffii (three strains). Vibrio mimicus (two strains) and Vibrio metschnikovii (one strain) were identified according to phenotypic features and cellular fatty acid composition. CONCLUSION: Environmental Aer. sobria isolates were atypical in their ability to grow at 42 degrees C, and were haemolytic, proteolytic and cytotoxic. Although it was present in a high proportion in the water samples, atypical Aer. sobria is not an indicator of polluted water. SIGNIFICANCE AND IMPACT OF THE STUDY: The incidence of Aeromonas in the drinking water reservoirs in the Far East of Russia is reported for the first time.     

Interannual variability in phytoplankton biomass and species composition in a subtropical reservoir

• 1 The interannual variability of the dominant phytoplankton populations is described in a subtropical reservoir in Queensland using weekly data for a 16-year period between 1978 and 1994. North Pine Dam, Brisbane, is in an area characterized by strong interannual variability in rainfall. This variability is linked to El Nino Southern Oscillation (ENSO) events. Between 1978 and 1994 periods of drought (during strong ENSO events) were interspersed by periods of flooding rains. Rainfall on the catchment and temperature and oxygen within the dam showed strong 40-day periodicities which also varied in strength interannually in response to ENSO events. Similar patterns of fluctuations in the 40-day periodicity have been found elsewhere in SE Australia. Seasonal cycles of stratification in the dam were a function of both hydrographic and hydrological events. Intermittent rain storms caused partial turnovers and large outflows. As much as 90% of the dam volume was exchanged in a single flood event.
• 2 The dominant phytoplankton species were similar to those frequently found in tropical and subtropical lakes and reservoirs. The phytoplankton community switched between cyanobacterial blooms (Cylindrospermopsis, Microcystis) during drought and falling water levels and diatom blooms (Aulacoseira) in response to inflows and seasonal turnovers. There appeared to be a subtle interaction between inflows, water column stability, the periodic overturns and the occurrence of the dominant species. All the dominant species showed long periods (2–4 years) of exponential increase or decrease superimposed on top of the seasonal fluctuations in abundance. These patterns of abundance led to marked interannual variability in the phytoplankton biomass. Climate variability had a major impact on the seasonal and interannual changes of the dominant phytoplankton species.
• 3 Phytoplankton biomass tended to be depressed for about 3 months after individual storm events but the data also displayed long-term lag effects (2–4 years) which destroyed any significant correlation between water residence time and biomass. Summer maxima of biomass dominated by cyanobacteria disappeared between 1985 and 1990 and were replaced by smaller winter peaks. The data presented here are not capable of unequivocally identifying the precise reason for these longer-term effects. Because of the implications for water quality management in subtropical and tropical reservoirs they warrant further study.

     

Rapid identification of Enterococcus italicus by PCR with primers targeted to 16S rRNA gene

AIMS: To develop a species-specific PCR assay with primers targeted to 16S rRNA gene for the identification of Enterococcus italicus, a new species of Enterococcus, involved in the production of Italian cheeses. METHODS AND RESULTS: The type strain of E. italicus (DSM 15952(T) - 16S rRNA gene accession no. AJ582753) and other strains of the species were subjected to a rapid identification by PCR using primer pairs located within the 16S rRNA gene. A species-specific PCR product of approximately 323 bp was obtained after amplification of all E. italicus strains tested. The specificity of the primers was validated with representatives of the most closely related genera and species and a number of other bacterial species. In addition, the technique enabled the recognition of E. italicus from cheeses. CONCLUSIONS: The protocol was highly efficient and sensitive, enabling the identification of E. italicus from cheeses. SIGNIFICANCE AND IMPACT OF THE STUDY: The species-specific PCR offers a reliable and rapid alternative to conventional phenotypic methods for the identification of E. italicus within the heterogeneous genus Enterococcus.     

晋阳湖丝状蓝藻的形态学分析与分子鉴定北大核心CSCD

蓝藻是地球上最古老的生物之一,其形态结构较为简单,为产氧型光合作用的原核生物。山西省晋阳湖为华北地区最大的人工湖,该研究以采自晋阳湖水体及岸边附着的蓝藻为材料,采用经典毛细管法分离纯化出5株丝状蓝藻,利用光学显微镜观察其形态结构特征(如细胞形状、藻丝体宽度、是否有鞘)和显微结构,并采用16S rRNA序列分析其系统发育关系,以明确晋阳湖的蓝藻种类,为预防湖泊蓝藻水华的发生、维护水资源环境稳定与生态平衡提供理论数据。结果显示:(1)所分离纯化的5株丝状蓝藻依形态特征归属于3个科,其中2株(JYH005和JYH012)为细鞘丝藻亚科(Leptolyngbyaceae),2株(JYH008和JYH022)为伪鱼腥藻科(Pseudanabaenaceae),1株(JYH010)为沙丝藻科(Desertifilaceae)。(2)基于16S rRNA序列构建的系统发育树显示,5株丝状蓝藻中JYH005为结丝藻属(Nodosilinea)的一种;JYH008可归为Arthronema,该株蓝藻在培养条件下观察到不同的形态特征,可能为新物种;JYH010为沙丝藻属(Desertifilum)的一种;JYH012可归为细鞘丝藻属(Leptolyngbya);JYH022与伪鱼腥藻科聚为一支,由于与该科其他藻相似度低于90%,且不能聚为一支,因此只能归为伪鱼腥藻科。研究表明,基于16S rRNA序列系统发育分析与形态学鉴定结果相一致。该研究结果丰富了山西省晋阳湖丝状蓝藻的多样性,为该湖的资源利用和环境保护提供了一定的科学依据。     

Cyanobacteria in Antarctica: ecology, physiology and cold adaptation.

Cyanobacterial species composition of fresh water and terrestrial ecosystems and chemical environment of water in Schirmacher Oasis in Continental Antarctica was investigated. Over 35 species of cyanobacteria were recorded. Diazotrophic species both heterocystous and unicellular contributed more than half to the count except in lake ecosystem. The species composition varied among the fresh water as well as terrestrial ecosystems. The physico-chemical analyses of water revealed its poor nurient content which might have supported the growth of diazotrophic cyanobacteria in an Antarctic environment. Among the cyanobacteria Oscillatoria, Phormidium and Nostoc commune were the dominant flora in most of the habitats. The physiological characteristics of isolated cyanobacteria strains indicated that N2-fixation, nitrate uptake, nitrate-reduction, ammonium-uptake, GS-transferase activity and photosynthesis was unaffected at low temperature (5 degrees C) which indicated low temperature adaptation for Antarctic cyanobacteria. This phenomenon was not evident in different strains of tropical origin. The temperature optima for N2-fixation for the different Antarctic cyanobacterial strains was in the range of 15-25 degrees C, nearly 10 degrees C lower than their respective reference strains of tropical origin. Similar results were obtained for cyanobacteria-moss association. The low endergonic activation energy exhibited by the above metabolic activities supported the view that cyanobacteria were adapted to Antarctic ecosystem.     

北京市各种水体蓝细菌物种多样性研究

2016至2018年的5月和9月研究了北京市五大水系53个水体蓝细菌的物种多样性。结果表明,共发现蓝细菌4目4科22属63种,优势种(IRI)为小型色球藻(Chroococcus minor(Kütz.) N?g.)、湖泊鞘丝藻(Lyngbya limentica Lemm.)、水华束丝藻(Aphanizomenon flos-aquae(L.) Rafls.)、小席藻(Phormidium tende(Menegh.) Gom.)、钝顶节旋藻(Arthrospira platensis)、小颤藻(Oscillatoria tenuis Ag.)、铜绿微囊藻(Microcystis aeruginosa)、水华微囊藻(Microcystis flos-aquae)。通过对北京各种水体的蓝藻优势种进行CCA分析,得出大部分优势种与活性磷、叶绿素a、温度、溶解氧、总碱度、总硬度、pH呈正相关,与TN、TP呈负相关,与蓝藻的特性较符合,其中活性磷是限制蓝细菌生长的重要因素。各水体蓝藻平均密度为1.32×10~6 ind/L,平均生物量为0.003 2 mg/L,多样性指数平均为0.45,2018年较2017年多数水体的密度和生物量下降,多样性指数上升,说明北京市水环境治理有所改善,但仍需继续加强治理。     

氮、磷对热带浅水湖泊惠州西湖蓝藻的控制

湖泊富营养化常导致蓝藻生物量的增加,水质恶化.于2011年2月至12月对热带浅水湖泊惠州西湖六个湖区的蓝藻群落结构进行研究,以了解其时空变化特征及主要影响因素.结果表明,以沉水植物为优势的元妙观湖区与南南湖蓝藻无明显的优势种;平湖蓝藻优势种为银灰平裂藻(Merismopedia glauca)和湖丝藻(Limnothrix sp.),南丰湖、北丰湖和北南湖的主要优势种均为银灰平裂藻(Merismopedia glauca).平湖、南丰湖、北丰湖和北南湖蓝藻丰度及生物量存在显著的季节变化.相关分析显示惠州西湖夏季蓝藻生物量受氮、磷盐控制.冬季温度的影响,蓝藻生物量与氮、磷的相关性不显著.