广东长潭水库浮游生物群落结构特征

长潭水库是广东梅州市重要的备用水源地,属于国家一类水源保护区。2010年7月,通过分析长潭水库浮游生物群落组成、生物量及多样性指数等群落结构特征和水体理化指标,揭示长潭水库富营养化水平。结果显示,长潭水库鉴定出55种浮游植物,隶属于6个门,优势种为绿藻门的栅藻（Scenedesmus sp.）、蓝藻门的微囊藻（Microcystis sp.）和伪鱼腥藻（Pseudanabaena sp.）、隐藻门的隐藻（Cryptophyta sp.）以及硅藻门的小环藻（Cyclotella sp.）和针杆藻（Synedra sp.）;藻类密度范围1.71×10⁶~2.44×10⁸ cells/L;浮游动物共检出44种,包括轮虫、枝角类和桡足类,其中轮虫是主要类群。综合营养状态指数评价结果显示,长潭水库部分水体呈轻度富营养化。典范对应分析结果显示,浮游动物、溶解氧、总氮、总磷和化学需氧量是影响长潭水库浮游植物群落结构的关键环境因子。     

放养鲢鱼(Hypophthalmichys molitrix C et V)对水库围隔浮游生物群落的影响

本文研究在水库围隔实验生态系统中鲢鱼对浮游生物群落的影响。结果表明,放养鲢鱼后,浮游动物生物量、浮游植物生物量、叶绿素a和浮游植物毛产量分别下降了58.7％、63.6％、52.5％和65.0％;透明度、浮游植物群落多样性指数分别提高了18.2％、32.5％;铜绿微囊藻数量减少了90.6％“水华”得到明显抑制。但小型绿藻(<20μm)数量未出现显著变化,因而其在藻类生物量中所占比例反而提高了82.3％。围隔内可被鲢鱼滤食的大型藻类(硅藻、甲藻、隐藻和绿藻(>20μm))占藻类生物量的85.8％,因此鲢鱼的存在能明显限制浮游植物的生物量。此外,放养鲢鱼还显著降低了水体中的COD,TP,DO和pH值,这表明鲢鱼对水质有净化作用。     

广东沿海与粤北山区中小型水库浮游生物群落比较分析

于丰水期和枯水期对广东山区水库(赤石迳水库)、沿海水库(大水桥、赤沙水库)三个水库的湖泊区和河流区进行研究,分析水质和浮游生物群落结构。三个水库之间的浮游生物群落均有所区别,地理位置和地形不同而引起的温度差异以及外源性营养盐输入是造成浮游生物种类和数量差异的主要原因。沿海水库不分层,而山区水库丰水期温跃层明显。各水库的氮磷比均较高,chl.a水平主要受磷限制,沿海水库则多喜暖性的种类,如裸藻、隐藻、沙居剑水蚤等,山区水库发现较多喜冷性浮游生物,如金藻、透明溞等,丰水期的甲藻丰度也相对高于枯水期。     

青藏高原柴达木盆地尕海盐湖浮游生物群落多样性特征的初步研究

青海尕海是青藏高原柴达木盆地比较典型的高盐度且具有丰富卤虫资源的盐湖 ,海拔高程 2 849.6m。 1997年夏季我们对尕海盐湖浮游生物主要类群群落多样性特征进行了初步调查。调查期间在内湖主要水体 5个断面2 2个采样站共发现浮游藻类 46种 ,平均密度为 5 4.39× 10 4 Cells/L ;浮游动物 12种 ,全湖平均密度为 8.2 2个 /L ,平均生物量 0 .2 9mg/L。通过盐度含量较高 (119g/L)的内湖主要水体采样断面与盐度含量较低 (1.8g/L)的湖西北岸小水面采样断面比较 ,浮游生物不论是在种类组成特征、群落的多样性还是其个体丰度都存在十分明显的差异。结果表明 :在盐湖生态系统中 ,盐度是决定生物物种多样性及其个体丰度的关键因素之一。     

飞来峡水库蓄水初期营养状态及浮游生物分布特征

于2000年丰水期和枯水期调查分析了新建河流型水库-飞来峡水库在蓄水初期的营养状态及浮游生物特征。结果表明:水库处于营养累积高峰期,已开始回落,但流域上游大量含磷废水使水库中磷含量继续上升,目前属于中营养型。共记录到浮游植物29种(属),以蓝藻门、绿藻门、硅藻门种类较多,其中丰水期以蓝藻和绿藻为主,枯水期是硅藻占优势,除大坝附近外,浮游植物两个季节密度变化不大,为0.39×10⁶cells·L^-1.浮游动物53种(属),其中包括僧帽溞和透明薄皮溞两种嗜寒性种类,丰度为52ind.·L^-1,枯水期高于丰水期,数量以轮虫和无节幼体为多。     

广东省大中型供水水库营养现状及浮游生物的响应

于2000年调查了广东省18座大中型供水水库的水质现状并探讨了浮游生物对营养水平的响应。总氮、总磷、透明度和叶绿素a分别为0．15～7.15mg／L、0．003～0．387mg／L、0．4～6．3m和0．6～32．3ug／L。总氮、总磷、透明度均与叶绿素a呈较高的相关性。根据这4个因子的综合加权营养状态指数为23．7～55．1,季节差异不大,大多数水库处于中营养状态。金藻在中-富及富营养型水库中没有分布,而蓝藻、绿藻、硅藻和甲藻在调查水库中均有比较广的营养生态位,但它们的密度及相对优势度在各营养型水库中有一定的差异。高营养水平水库有较高的细胞密度和叶绿素a含量。营养水平较低的水库浮游植物以硅藻-甲藻、硅藻-绿藻或金藻-硅藻为主;营养水平较高的水库以蓝藻-硅藻或蓝藻-绿藻为主,并有较高的裸藻密度。浮游动物基本上以桡足类为优势种群,但在中-富营养和富营养型水库中,哲水蚤种类比低营养型水库中少。枝角类优势种类在各营养型水库差别不大。轮虫对水体营养水平的响应相对比较显著。低营养水平水库的轮虫以广营养型、中营养型或寡中营养型种类为主,种类数目比较少;富营养和中-富营养型水库的轮虫以喜在中营养到富营养条件下生长的种类为主,且轮虫种类数目比较多。     

嘉陵江浮游生物群落结构研究

为揭示嘉陵江梯级水库浮游生物群落结构特征,按枯水期和丰水期对嘉陵江12个梯级水库24个样点进行浮游生物的野外采集,分析其群落结构的物种组成,并采用Shannon-wiener指数、Margalef指数和Pielou均匀度指数进行分析.结果表明:嘉陵江四川段浮游植物共8门42科95属171种,浮游动物的组成共有4纲9目21科30属62种;浮游动物优势种类有21种.浮游生物评价结果表明梯级库区水质处于中度污染状态.     

黄河上游玛曲段春季浮游生物群落结构特征

为了了解黄河上游玛曲段的水质状况,于2006年4—5月对黄河玛曲段干流浮游生物的群落组成进行了调查。结果表明：全段的浮游植物共有5门23种（属）,浮游植物密度为3.2×10⁴～54×10⁴ cells·L^-1,平均密度为19.7×10⁴ cells·L^-1,生物量为0.069～0.464 mg·L^-1,平均生物量为0.228 mg·L^-1,其中密度最高的为齐哈玛,生物量最高的为玛曲大桥;浮游动物共有2门10种（属）,密度为670～1273 cells·L^-1,平均为881.56 cells·L^-1,生物量为0.044～0.089 mg·L^-1,平均为0.064 mg·L^-1;该河段浮游生物组成多以冷水性为主;浮游植物多样性指数介于2～3,表明黄河上游玛曲段水质呈轻度污染;浮游生物丰富度与均匀度值均较低,群落结构组成不稳定,易受外界环境的干扰。     

罗非鱼对微型生态系统浮游生物群落和初级生产力的影响

本文报道罗非鱼不同放养密度对淡水微型生态系统结构与功能影响的部分研究结果。罗非鱼的捕食使微型生态系统中浮游动物密度下降,引起浮游植物密度、初级生产力和P/R系数的增长,同时使水柱透明度降低而pH值增高,以致于实验后期微型生态系统具有典型的富营养化水体的特征。就罗非鱼放养密度不同的微型生态系统而言,虽然其浮游生物密度和P/R系数存在显著的组(或部分组)间差异,但不同密度组的初级生产力水平和最终的理化状况相差不大,并且罗非鱼的收获量甚为接近。因此,实验条件下微型生态系统的群落结构和代谢的变化,按照营养级联假说不能很好地予以解释,表明微型生态系统是由捕食(下行影响)和理化因素(上行影响)共同调节或控制的。根据微型生态系统的实验结果推断,放养较大密度的罗非鱼,将会加速营养物负荷较高的天然水域富营养化的进程。     

Responses of zooplankton body size and community trophic structure to temperature change in a subtropical reservoir

Understanding the effects of global warming on trait variation and trophic structure is a crucial challenge in the 21st century. However, there is a lack of general patterns that can be used to predict trait variation and community trophic structure under the ongoing environmental change. We investigated the responses of body size and community trophic structure of zooplankton to climate related factors (e.g., temperature). Isotopic niche breadth was applied to investigate the community trophic structure across a 1‐year study from a subtropical reservoir (Tingxi Reservoir) in southeastern China. Body size and community isotopic niche breadth of zooplankton were larger during water mixing than stratification periods and correlated significantly with water temperature change along the time series. The contributions of intra‐ and intertaxonomic components to body size and community trophic structure variation showed significant relationships with the temperature change going from the mixing to stratification periods. Water temperature imposed direct effect on body size, while direct and indirect effect on the community trophic structure of zooplankton occurred through trophic redundancy along time series. Water temperature and community properties (e.g., body size, trophic redundancy, or trophic interaction) showed complex interactions and integrated to influence community trophic structure of zooplankton. Our results can expand the knowledge of how elevated temperature will alter individual trait and community trophic structure under future climate change.     

Plankton richness in a eutrophic reservoir (Barra Bonita Reservoir,SP, Brazil)

Species richness of plankton was studied in a eutrophic reservoir (Barra Bonita Reservoir) of the Middle Tietê River, São Paulo State, Brazil, during the period 1985–1986. This reservoir is formed by two rivers: the Tietê and the Piracicaba (the main tributaries), of which the Tiête is more eutrophic, having conductivity and nutrient concentration values twice those of the Piracicaba. In addition, the reservoir is fed by 114 smaller tributaries. Monthly sampling was carried out at three stations representing different environmental conditions: St1 on the Tietê, S2 on the Piracicaba, and St3 at the confluence of the two rivers. For the phytoplankton community, the Piracicaba River (St2) proved the richest site, with a listed 72 species with abundance of Chlorophyta, while St1 and St3 registered 59 and 50 species, respectively, with abundance of Cyanophyta. For the zooplankton community a great difference was not registered in species number at the three stations but the species composition and dominant species of rotifers and copepods were quite different. The occurrence of Mesocyclops meridianus and Metacyclops mendocinus, specific for St2;Mesocyclops ogunnus and Notodiaptomus iheringi, specific for St1, and that of these two species plus Mesocyclops meridianusat St3 shows that the conditions combining at this station were favorable to Mesocyclops meridianus but not to Metacyclops mendocinus. Both for phytoplankton and zooplankton, high values found of species richness were compared to species richness of natural lakes, e.g., Dom Helvecio, a monomictic stable lake in eastern Brazil, and another fifteen lakes in the same region.In conclusion, this work shows that environmental gradients are strong selective factors that enhance plankton richness in eutrophic reservoirs exhibiting environmental instability. This fact could explain the presence of a high number of plankton species associated with a high number of individuals in Barra Bonita Reservoir, supporting the effects of the intermediate disturbance hypothesis.     

密云水库的浮游生物群落

2002年4～10月对密云水库浮游生物群落的调查结果显示：浮游植物有6门,58属,122种,细胞密度为565．30～10^4cells／L,4月份硅藻(Bacillariophyta)占优势,6～10月蓝藻(Cyanophyta)占绝对优势．浮游植物优势种群有水华微囊藻(Microcystis flas-aquae)、颗粒直链藻(Melosira granulata)、梅尼小环藻(Cyclotella meneghiniana)、角甲藻(Ceratium hirundinella)等。浮游动物有36种,密度为4761ind/L;浮游动物具有原生动物在数量上占绝对优势．轮虫次之,枝角类与桡足类数量较少的特点。浮游动物的优势种群有弹跳虫(Halteria grandinella)、急游虫(Stromlridium uiHde)、针簇多肢轮虫(Polyarthra trigla)、螺形龟甲轮虫(Keratella cochlearis)、广布中剑水蚤(Mesocyclops leuckarti)、长额象鼻蚤(Bosmlna longirostris)等．与1980年监测结果相比,密云水库浮游生物总密度上升较快,群落结构和优势种群也发生了明显变化．浮游生物优势种群的指示作用显示,在植物生长季节,库区水体已进入富营养状态。     

广州抽水蓄能电站蓄水库蓄水初期浮游生物调查

对我国首座核电站配套工程的抽水蓄能电站水库蓄水初期的浮游生物进行了调查。蓄水水库由上下两水库组成。两水库的浮游生物种类组成显著不同。上水库浮游植物共记录到３０种（属）,浮游动物１２种（属）;下水库浮游植物１９种（属）;浮游动物２５种（属）。上下两水库浮游生物数量均较贫乏,表明浮游生物群落尚处于初期发育阶段,但在局部浅水处已出现小规模的蓝藻水花,认为是水库蓄水初期必然的结果     

油藏微生物群落结构解析

微生物采油(Microbial enhanced oil recovery,MEOR)以其费用低廉、无环境污染、施工简单、应用范围广等优点得到学者以及油田开发者的认同。油藏中的微生物类型多样且功能各异,可促进原油的开采,大幅度提高油气资源的利用率。因此分析油藏中微生物的类型和组成,了解土     

Plankton community of a polyhumic lake with and without Daphnia longispina (Cladocera)

The impact of Daphnia longispina (Cladocera) on the plankton food web was studied in a polyhumic lake where this species comprised almost all zooplankton biomass. Plastic enclosures (volume 7 m³) were inserted into the lake retaining the initial water stratification except that in one enclosure zooplankton was removed. After the removal of Daphniaa rotifer, Keratella cochlearis, ciliates and heterotrophic nanoflagellates increased markedly and the density and biomass of bacteria decreased. Edible algal species, Cryptomonas rostratiformisand three small chrysophytes,Ochromonas, Pedinella and Spinifermonas, took advantage of the removal of Daphnia, while more grazing-resistant species declined. In spite of the changes in the species composition of phytoplankton, the removal of Daphnia did not affect the biomass, primary production or respiration of plankton. The results implied that the density of heterotrophic flagellates and ciliates was controlled by Daphnia, but in its absence the former took its role as the bacterial grazers.     

Plankton relationships under small water level fluctuations in a subtropical reservoir

In reservoirs, variations in water level may affect plankton biomass and species composition. Studies on the effect of water-level fluctuations are scarce and restricted to Europe and Australia. In the Río Tercero Reservoir (Argentina), the management policies of a nuclear-power plant require a minimum depth of 650 m. During periods of excessive rainfall, however, the input is such that the excess passes over the spillway, thus causing a high turnover of water. Phytoplankton, zooplankton, and physicochemical variables were monitored over 2 years at three sampling stations during a period with annual precipitation higher than the historical annual mean. Different hydrological situations occurred based on precipitation, spillway outflow, and water-renewal rate. At high renewal rates, phyto- and zoo-plankton diversities peaked. During high outflow periods phytoplankton biomass peaked through the contribution of Ceratium hirundinella. Once the spillway outflow ceased, stable conditions (low renewal rates) were achieved, thus allowing the onset of biological interactions. Maximum phytoplankton density (mainly Actinocyclus normanii) was reached at such times, and efficient grazers (Daphnia laevis) with long life cycles dominated in terms of biomass. The structure and dynamics of the plankton community could be altered by changes in hydrological conditions (renewal rate and spillway outflow) that act to compromise the apparent stability imposed by steady water levels. These variables must be considered to identify disturbance conditions and improve knowledge of reservoir environments, so as to implement appropriate management practices.     

Environmental variability drives phytoplankton assemblage persistence in a subtropical reservoir

Temporal changes of assemblages may result from environmental variability and reflect seasonal dynamics of their ecosystem. In the subtropics, the hydrological regime is usually characterized by well‐defined wet and dry seasons, regulating discharge and influencing a series of environmental variables that affect phytoplankton persistence. Therefore, we may expect that dry seasons are environmentally more stable than wet seasons. We analysed interannual phytoplankton assemblage variability (or, inversely, persistence) in a subtropical reservoir sampled every austral summer and winter during 5 years. We tested (i) if phytoplankton assemblage structure differed between the dry (summer) and wet (winter) seasons; (ii) if assemblage persistence differed between the seasons; (iii) if assemblage persistence was related to environmental stability; and (iv) if assemblage dissimilarity increased over time. Phytoplankton assemblages differed between the summer and winter seasons. Winter indicator species were mostly Bacillariophyceae or Cryptophyceae, whereas Cyanophyceae and Chlorophyceae taxa were more frequent and abundant in summer. Assemblages in the dry season were more persistent among years than those occurring during rainy periods. Similarly, environmental variability tended to be lower among dry than among rainy seasons. The relation between the phytoplankton temporal cycle and the temporal patterns of environmental variability supports our prediction that high environmental stability results in more persistent assemblages. Assemblage dissimilarity increased as sampling years were farther apart, for both seasons. Additionally, assemblages in the rainy periods showed a more pronounced increase in dissimilarity, as their changes among years were less predictable. We found a clear temporal pattern and an increased dissimilarity over time in the phytoplankton assemblage structure. Unravelling these temporal patterns may improve our understanding of phytoplankton temporal dynamics, and may have implications for management and monitoring programs. High dissimilarity of assemblages among years, particularly among rainy periods, can obscure human impacts, and monitoring programs should take this into account.     

Influence of Environmental Heterogeneity on the Structure of Testate Amoebae (Protozoa,Rhizopoda) Assemblages in the Plankton of the Upper Paraná River Floodplain,Brazil

In freshwater environments, testate amoebae are usually found associated with macrophytes and sediments and many studies have suggested that their occurrence in plankton samples is accidental. This implies that predictable patterns detected in planktonic assemblages should not be observed in testate amoebae assemblages. This hypothesis was tested in this study. Plankton samples were collected from different environments in the Upper Paraná River floodplain. Results show that patterns in species composition and abundance of testate amoebae are predictable, and that dominant species tend to present characteristic shell morphology in hydrologically different environments. We suggest that testate amoebae must be routinely included in plankton ecology studies, at least in floodplain environments.