基于CCA的典型调水水库浮游植物群落动态特征分析

调水水库是一类特殊的水体,其浮游植物群落的组成与动态的调节机制与其它水库存在较大的差别。为了解这类水库浮游植物群落的特征,于2005年1月-12月,对位于广东省珠海市的调水型供水水库--大镜山水库的浮游植物和相关的理化因子进行了2周1次的采样。全年共检测到浮游植物100种（属）;浮游植物丰度在0.86-106.27×106cells·L^-1之间,生物量在1.08-20.45mg·L^-1之间变化;全年以假鱼腥藻（Pseudanabaena sp.）为主要优势藻,肘状针杆藻（Synedra ulna.）在冬春为次优势藻,浮游植物群落相对比较稳定。运用典范对应分析（CCA）方法对浮游植物群落的组成及动态与环境因子之间的关系进行了分析和探讨。样品（cases）的CCA分析表明,全部的样品分布在主轴1和主轴2构成的4个象限内,与四季相对应,样品在4个象限的分布并不均匀,反映了热带水库所处的气候四季不分明的特点,冬春季很短,夏秋季较长,但夏秋与冬春有较为明显的分割;蓝藻门、裸藻门和硅藻门的藻类主要分布在夏、秋季所对应的象限内,而绿藻门的大部分,金藻门和隐藻门的藻类分布在冬、春季所对应的象限内。水温和降雨量是大镜山水库浮游植物群落结构动态的主要驱动因子,降雨量不仅影响水库水位,同时直接影响调水量和入库的营养盐负荷。     

热带调水水库春季浮游植物群落的结构与动态

于2005年1-6月,对南亚热带调水水库—大镜山水库的水文、营养盐(N、P)和浮游植物进行了调查研究。共检测到浮游植物76种;浮游植物总的细胞数量在4.925×106-63.65×106cellsL-1之间,浮游植物的总生物量在1.632-20.420mgL-1之间。假鱼腥藻(Pseudanabaena sp.)是主要优势藻,但是早春(1-3月)假鱼腥藻和肘状针杆藻(Synedraulna)共同成为优势藻。浮游植物细胞的丰度晚春(4-6月)比早春的要高,但是生物量却比早春的低。在水文过程与其它水库有一定差别的典型调水水库,水温是引起浮游植物种类组成变化的主要原因。浮游植物组成与动态是受入库营养盐和水动力学的变化所影响的。     

南亚热带贫营养水库春季浮游植物群落结构与动态

2005年1~6月,通过每两周一次的高频率采样,对南亚热带贫营养水库——梅溪水库的水文、营养盐和浮游植物进行了调查,并计算水体浮游植物生物量。主要结果如下:梅溪水库浮游植物具有物种少,生物量低,以飞燕角甲藻(Ceratium hirundinella)和多甲藻(Peridinium sp.)为优势藻的特征。12次采样24个样品共检测到浮游植物42种。浮游植物在早春(1~3月)和晚春(4~6月)有显著的差别,其中每次采样浮游植物早春平均13种,晚春平均21种。浮游植物总的细胞丰度为31~273 cells·ml^-1,总生物量为0.176~2.024 mg·L^-1之间。晚春浮游植物平均生物量明显高于早春。低营养盐和弱酸性水体有利于能够垂直迁移获得营养的鞭毛藻类和其它藻类之间竞争,而使其成为整个春季优势类群。在晚春,随着水温显著增加,浮游植物丰度和生物量也明显增加,但是降雨的增加降低了水体的透明度,大大减缓了由水温上升导致生物量增长的趋势。水温是梅溪水库浮游植物变化的主要限制因子,但是降雨有明显的干扰作用。     

广东省典型水库浮游植物群落特征与富营养化研究

研究了广东省19座主要水库2000年丰水期和枯水期浮游植物状况,并根据浮游植物群落结构和多样性指数对水库进行营养状况评价。结果表明,东江流域的新丰江和白盘珠水库水质良好,属于贫营养型水库;大部分水库为中营养型,而鹤地、契爷石和石岩这3座位于沿海经济发达地区水库属于富营养型。流域上游水库水质明显优于下游水库,山区水库水质优于沿海水库,东江流域水库水质普遍较好。北江流域次之,而粤西沿海和珠江三角洲地区各水库均受到不同程度的污染。     

一座南亚热带小型贫营养水库浮游植物群落结构及季节变化

库容大小是影响水体水动力学过程的一个重要变量,它能在很大程度决定生态系统的结构,特别是浮游植物的群落结构.为了解小型贫营养水库浮游植物的群落特点,于2006年4、8、12月对位珠海市的贫营养小型水库-吉大水库的浮游植物群落结构进行采样和计数分析.3次采样共检出浮游植物32种,浮游植物细胞丰度的变化范围在69～342 cells·mL^-1,生物量的变化范围在1.34～3.69 mg·L^-1,夏季浮游植物的丰度和生物量明显高于冬季.甲藻是最主要的优势种类,且相对优势度较为稳定.夏季,隐藻门的隐藻(Cryptomonas sp.)和绿藻门的鼓藻(Cosmarium spp.)大量出现,甲藻的相对优势度有所降低.冬季,隐藻数量急剧下降,但硅藻门的颗粒直链藻(Aulacoseira granulata)大量出现,与甲藻共同成为水体中的优势种.由降雨引起的营养盐浓度增加是浮游植物变化的主要影响因子,而透明度全年维持较高的水平为浮游植物的生长形成了有利条件,此外,较为稳定的水体和甲藻利用营养盐的能力使得甲藻成为浮游植物中的最主要的优势种.     

大型热带水库-松涛水库枯水期浮游植物群落特征

松涛水库是一个大型热带水库,分为两个主要水域:番加洋和南丰洋,2003年12月对该水库的这两个水域的浮游植物进行采样,共发现7门65种藻类。松涛水库番加洋库区水体的浮游植物总细胞密度为1.08×10⁶cells·L^-1,主要种类组成为蓝藻(Cyanophyta)-绿藻(Chlorophyta)型。松涛水库南丰洋库区水体的浮游植物群落为细胞密度为1.14×10⁶cells·L^-1,主要种类组成为绿藻(Chlorophyta)-硅藻(diatom)型。松涛水库库区水体总体已为避-富营养,其中富营养型浮游植物指示种类有:铜绿微囊藻(Microcystis aeruginosa Kütz.),针状蓝纤维藻(Dactylococcopsis acicularis),镰形纤维藻(Ankistrodesmus falcatus),小环藻(Cyclotella menighiniana),模糊直链藻(Melosira spp.)等。与亚热带和温带的水库比较,处于热带地区的松涛水库浮游植物,在湖泊区微囊藻等适应高温高光强的种类具有更高的细胞密度。松涛水库河流区最主要的优势种是硅藻门的针杆藻。     

南亚热带河流型水库浮游植物群落的季节变化：以广东飞来峡水库为例

于2003年4-12月调查了广东省飞来峡水库的水文、营养盐分布状况和浮游植物种类与数量,分析了浮游植物群落的种类及数量组成与动态特征,探讨了其动态变化的驱动因子。结果表明,飞来峡水库是一个典型的河流型大型水库,水力滞留时间短,年均值低于15 d;降雨量主要集中于夏季,最短水力滞留时间只有8 d。水温全年没有分层现象。丰水期营养盐和叶绿素a高于枯水期。浮游植物生物量低,细胞密度在21.7×103-808×103 cells L-1之间变化,没有超过106 cells L-1,叶绿素a的平均浓度为2μg L-1。浮游植物种类较多,4次采样共检到140种。种类组成上有较大变化,4月份有83种,以硅藻为主;7月和9月超过90种,以绿藻为主;12月有51种,蓝藻、绿藻和硅藻种类数量相当。优势种类的构成上与温带水库不同,硅藻仅在低水温时期为优势类群,而在丰水期则以蓝藻、绿藻和硅藻共同占优势。硅藻的主要优势种是变异直链藻(Melosira varians)、梅尼小环藻(Cyclotella menighiniana)和针杆藻(Synedra spp.)。绿藻种类组成季节变化较大,没有明显的优势种类。丰度相对较高的有美丽胶网藻(Dictyosphaerium pulchellum)、集星藻(Actinastrum hantzschii)和空球藻(Eudorina elegans)等。蓝藻的优势种以粘球藻(Gloeocapsa sp.)、优美平列藻(Merismopedia elegans)和伪鱼腥藻(Pseudoanabaena sp.)为主。与绿藻不同的是蓝藻的优势种在全年均可出现。隐藻只在水力滞留时间较长、温度较低的12月份占优势,主要优势种为啮蚀隐藻(Cryptomonas erosa)、尖尾蓝隐藻(Chroomonas acuta)。     

深圳石岩水库浮游植物群落时空动态特征及其影响因素分析

于2013 年5 月至2014 年4 月对深圳石岩水库进行采样, 研究了深圳石岩水库浮游植物群落组成、时空动态及其主要的环境影响因素, 以期为该水库水质的保障和改善提供科学依据。石岩水库全年共检测到浮游植物7 门90属, 以绿藻门(41.1%)、硅藻门(30.0%)和蓝藻门(20.0%)为主。浮游植物的种类在9 月份最丰富, 有61 种, 8 月份最少, 仅有18 种。各采样区的浮游植物丰度, 在6 月份达到最大值, 为1.76×108 cells·L^–1, 在10 月份出现最低值, 为2.74×106 cells·L^–1。绿藻、硅藻和蓝藻的丰度之和在全年所占比例都较高, 变化范围为96.74%-100%, 以蓝藻居多, 占51.55%-92.23%,其中, 绿藻门的优势属为十字藻属(Crucigenia)、栅藻属(Scenedesmus)、小球藻属(Chlorella); 硅藻门的优势属为直链藻属(Melosira)、小环藻属(Cyclotella); 蓝藻门的优势属为假鱼腥藻属(Pseudanabaena)。冗余分析(Redundancy analysis,RDA)表明: 全部样品分布在轴1 与轴2 构成的4 个象限内, 轴2 左侧与冬(春秋)季对应, 轴2 右侧与夏季对应; 绝大多数藻类分布在冬(春秋)季对应的象限内, 少数藻类包括硅藻门的卵形藻属(Cocconeis)、蓝藻门的平裂藻属(Merismopedia)、尖头藻属(Raphidiopsis)和鞘丝藻属(Lyngbya)以及绿藻门的衣藻属(Chlamydomonas)分布在夏季所对应的象限内; 研究结果表明影响石岩水库浮游植物群落结构动态的主要驱动因子是水温(Temperature, TEMP)、总有机碳 (Total Organic Carbon, TOC)、硝酸盐氮(NO3-N)和总氮(Total Nitrogen, TN)。     

大沙河水库冬季浮游植物群落结构与水华分析

于2009年12月、2010年1月和2月对广东省大沙河水库湖泊区距水表层0.5m、5m和10m三个水层的浮游植物进行了定性与定量分析,同时对环境变量进行了测定.采样期间三个月的总降雨量为263mm,水温范围在15.5～19.4℃之间,水体处于混合状态.三次采样中,共检测出浮游植物69种(属),隶属于6个门,浮游植物丰度范围在4.1×10⁶～14.8×10⁶cells·L^-1之间.三个水层的浮游植物优势种类差异不显著(p>0.05),丰度的主要优势种为蓝藻门的卷曲鱼腥藻(Anabaena circinalis)、铜绿微囊藻(Microcystis aeruginosa),这两个种的丰度之和占总丰度的70%以上,在2009年12月和2010年2月的表层出现了轻度鱼腥藻和微囊藻水华.蓝藻自身的浮力调节机制和适应低磷的生活策略是其成为优势种的重要原因,相对稳定的外部条件、水体混合与富营养共同导致的光的可获得性的减少是形成蓝藻水华的关键外部因子.     

A comparison of phytoplankton community assemblages in artificially and naturally mixed subtropical water reservoirs

1. The effect of mechanical and natural mixing of water on phytoplankton community assemblages was compared in one reservoir with a destratification unit operating during the wet summer months (North Pine Reservoir) with two adjacent reservoirs without artificial mixing (Wivenhoe and Somerset Reservoirs) over 6 years in subtropical Australia. 2. All three reservoirs were dominated by cyanobacteria, with the same three genera representing 75–80% of the abundance, i.e. Aphanocapsa/Merismopedia/Cyanodictyon group, Cylindrospermopsis raciborskii (Wo?oszyńska) Seenayya et Subba Raju and Planktolyngbya. Associations between the dominant genera were consistent across all three reservoirs although there were reduced seasonal differences in abundance in North Pine Reservoir compared with the other reservoirs. 3. Peaks in abundance of the solitary filamentous species C. raciborskii and Planktolyngbya occurred earlier and the densities of the colonial species Aphanocapsa/Merismopedia/Cyanodictyon were lower in the reservoir where the destratification unit was switched on in spring compared with the naturally mixed reservoirs, possibly reflecting the differential effect of artificial mixing on colonial versus solitary filamentous species. 4. Phosphate concentrations were positively correlated with algal densities in the two naturally mixed reservoirs but not the artificially mixed reservoir where phosphate concentrations at the surface were near the limit of detection (0.06 μm P). Artificial mixing may, therefore, promote the growth of species able to utilise and store low concentrations of phosphate, such as C. raciborskii.     

亚热带水库浮游植物季节动态及其与环境因子的关系

以亚热带黄村水库流域为研究对象,探讨了浮游植物群落的季节变化及其与环境因子的关系。共鉴定出浮游植物51种,种类最多的是绿藻门（18种）（35.29%）,其次是硅藻门（15种）（29.41%）和蓝藻门（11种）（21.57%）。从浮游植物群落季节组成差异来看,春季（62.96%）和夏季（71.03%）蓝藻门丰度最高,秋季（56.11%）和冬季（80.74%）硅藻门丰度最高。黄村水库流域优势种尖尾蓝隐藻（Chroomonas acuta）和曲丝藻（Achnanthidium sp.）在春夏秋冬季节均存在。多样性指数表明该流域水体处于中营养状况。温度、电导率和营养盐是影响浮游植物群落组成最主要的环境因素。     

Spatial and temporal variation of phytoplankton in two subtropical Brazilian reservoirs

The purpose of this study was to verify the longitudinal distribution of phytoplankton biomass in two subtropical Brazilian reservoirs in the State of Paraná and investigate intervening factors on changes in phytoplankton biomass according to functional groups. In the Capivari and Segredo reservoirs, samples were obtained every 3 months during 2002, along a longitudinal axis (fluvial, transition, and lacustrine zones) at different depths. One hundred and eighteen taxa were identified, with Chlorophyceae as the most specious group. During the study period, both reservoirs had mostly low biomass values (less than 1 mm³ l⁻¹). The short retention time of these reservoirs constituted the principal limiting factor to phytoplankton development. Biomass values above 1 mm³ l⁻¹ were observed in the Capivari fluvial zone in March and in the Segredo lacustrine zone in December, with dominance by Microcystis aeruginosa Kütz (L_M) and Anabaena circinalis Rab. (H₁), respectively. Vertical and horizontal gradients of analyzed abiotic variables and phytoplankton biomass were observed. Considering the phytoplankton biomass values, both reservoirs were oligotrophic for the duration of the study. The Canonical Correspondence Analysis (CCA) evidenced temporal and spatial gradients of phytoplankton biomass; nevertheless, it did not follow the classic model proposed for deep reservoirs, since higher biomass was registered in the lacustrine zone during some months and in fluvial zones during other months. Distinct functional groups of phytoplankton characterized both studied reservoirs. Capivari Reservoir was best characterized by L_M and Y groups, indicative of its greater water column stability and higher phosphorus concentration, whereas Segredo Reservoir was principally characterized by the MP functional group, indicative of its greater mixing zone extension and higher nitrate concentration. The obtained results also evidenced the influence of morphometric conditions and watershed purposes as important structuring factors of phytoplankton biomass in these reservoirs. Handling editor: L. Naselli-Flores     

A plea for more ecology in phytoplankton ecology

When looking for a pattern of phytoplankton behaviour across trophic gradients, we need to cross the boundaries between different disciplinary areas, from autoecology to systems ecology, because eutrophication is a complex process which involves different time scales and different levels of community structure. Thus, we submit our observations to the muddled conceptual world of assemblage ecology. These inaccuracies arise, for example, from both species and community arguments; eutrophication as a fertilization or a metabolic phenomenon; and the notions frequently interwoven of pattern, process and rules. We suggest that it is advantageous to tackle this issue from the perspective of general ecology, rather than from a specifically planktonic orientation. In this way, useful general ecological tools, for example, time series and assembly-rule studies, can be used. Time-series study allows the dynamics of any variable to be described or to show that long term variable fluctuations may sometimes be unregulated, in response to some exogenous factor. Rules of assembly help us to resolve which traits are selectively involved during the eutrophication process. In this context, we advocate (1) the use of traits instead of morphospecies in phytoplankton studies, (2) looking for the dynamic patterns of phytoplankton with eutrophication, (3) the use of time series techniques to study phytoplankton trajectories, (4) the use of assembly rules to discern patterns in the formation of multispecies assemblages, (5) the consideration of the pelagic food-web in studies of phytoplankton dynamics and, as an overall suggestion, to borrow knowledge and inspiration from general ecology.     

The structure of phytoplankton assemblages in Sicilian reservoirs: some hyphoteses on the driving factors

Abstract

From the analysis of the results of several researches carried out into Sicilian reservoirs to investigate their phytoplankton assemblages, it was highlighted that there is not any clear relationship between the trophic spectrum and the structure and composition of phytoplankton. Only a general increase of total biomass is detectable as the trophic state rises up. Anyway, such increase may cause several secondary modifications in the physical and chemical environment that may act as multidimensional segregating factors for phytoplankton organisms. In these secondary modifications, coupled with the peculiar morphology and hydrology of the water bodies, have to be sought the mechanisms governing the structure of phytoplankton assemblages.     

A comparison of phytoplankton assemblages in the Chesapeake and Delaware estuaries (USA), with emphasis on diatoms

The Delaware Bay is characterized as having greater nutrient and turbidity levels than the Chesapeake Bay. In reference to these differences, a one year study was conducted to identify any similarities and differences in the phytoplankton populations in these estuaries. The results indicated patterns of similarity in the diatom composition, with the total phytoplankton assemblage forming two site groups along a salinity gradient in each bay. These site groups were associated with stations located in the tidal fresh-oligohaline and meso-polyhaline regions of both estuaries. The seasonal concentrations of diatoms and total phytoplankton in both of these regions were higher in the Chesapeake Bay.Subtle differences between the two estuaries include a more diversified and abundant assemblage of neritic phytoplankters (including dinoflagellates) are present in the lower Chesapeake Bay. In contrast, a diatom dominated community is more characteristic of Delaware Bay. It is suggested the entry of neritic species into lower regions of the estuaries was enhanced by the reduced amount of rainfall and flow rates that occurred during the study period. The greater success of neritic species in the Chesapeake Bay is attributed to the lower turbidity of that estuary compared to Delaware Bay.     

景洪水库浮游植物群落结构变化及与水质的关系

景洪水库是澜沧江下游的重要梯级开发水库,具有重要的生态战略地位。为评估景洪水库水质和浮游植物群落结构现状,本研究根据库区水位和季节变化在2021年3月、6月、9月开展了库区水质和浮游植物监测。结果表明：景洪水库各监测点位水质较好,满足《地表水环境质量标准》Ⅱ类水质标准,富营养化评价结果为贫营养至中营养,但水质和营养状态从3月至9月呈现逐渐下降的趋势; 3月至9月浮游植物密度增加、多样性降低,随着季节变化浮游植物优势种发生明显改变,3月份优势种为隐藻门（Cryptophyta）和硅藻门（Bacillariophyta）,到9月份库区演变为蓝藻门（Cyanophyta）为主。RDA分析表明总有机碳和透明度与浮游植物群落结构变化显著相关。建议后期需加强景洪水库水生态环境监测与评估,预防水体富营养化和蓝藻水华的发生。     

额尔古纳河流域秋季浮游植物群落结构特征

2008年8-9月对额尔古纳河流域5个重要水体呼伦湖、乌兰泡、二卡湿地、伊敏河和哈乌尔河进行浮游植物调查,结果显示：1）共鉴定浮游植物8门82属177种（含变种）,以绿藻和硅藻种类最多,绿藻有36属77种,占43.5%,硅藻21属54种,占30.5%;其次是蓝藻,13属26种,占14.7%;裸藻4属11种,占6.2%;其他藻类仅占5.1%;2）在呼伦湖共有64属121种,乌兰泡47属88种,二卡湿地62属116种,伊敏河41属59种,哈乌尔河32属54种;优势度分析显示：呼伦湖与乌兰泡优势种为蓝藻和绿藻,二卡湿地为硅藻与隐藻,伊敏河与哈乌尔河为硅藻;蓝藻个体密度在乌兰泡与呼伦湖最大,分别为5.17?106 ind./L和4.01?106 ind./L,而硅藻密度则在二卡湿地、伊敏河与哈乌尔河占优势,分别为1.40?106 ind./L、1.84?105 ind./L与4.89?105 ind./L;此外,聚类分析显示5个水体的浮游植物群落按结构特征可分为两大类;3）与历史记录相比,呼伦湖的优势种转变为细胞较小的坚实微囊藻(M. firma)与不定微囊藻(M. incerta),这种小型化的趋势表明呼伦湖水体富营养化程度加剧;4）综合多种指标对水质状况进行评估：呼伦湖、乌兰泡为中-富营养水体,二卡湿地为中营养水体,伊敏河与哈乌尔河属于贫-中营养水体。     

Effects of species partition on explanatory variables in direct gradient analysis - a case study from Senegal

Abstract. Species-environment data from Senegal, West Africa, are used to study the effects of partition of a large species data set into subsets corresponding to rare and common species respectively. The original data set contains 129 woody plant species from 909 plots and 60 explanatory variables. By applying Canonical Correspondence Analysis to data subsets, marked differences in the forward-selected variables were detected. The highest resemblance was found between the complete species set and the common species subset. Only one of eight selected variables was common to all species and the rare species groups. These findings were tested with partial ordination, applying the selected variables from the original species group (Vb), as variables and covariables to the analyses of common and rare species. For the common species this application resulted in a constrained ordination with higher eigenvalues as compared to the set of variables selected with reference to the common species group. Using the rare species group, the application of Vb gave a much lower sum of eigenvalues than did the ordination with selected variables based on the rare species group only. Evidently, the set of variables selected on the basis of the rare species data were more significant. Hence, the resulting gradients depend on the frequency of the species. Gradient analysis is apparently only valid for groups of species with closely resembling characteristics. This implies that different functional types of species, with different distributions and abundances, respond individually to environmental variation. Extrapolating deduced gradients from one species group to another maybe risky, particularly when used in vegetation modelling.