用微型生物群落评价常德市水系的研究

本文应用PFU法对常德水系四季微型生物群落的结构和功能进行了分析。根据MacArthur-Wilson平衡模型提出了3个功能参数,测定了微型生物的2个结构参数。同步进行了16个站四季的水质分析,提出化学综合污染指数(P)。经统计学处理,P和微型生物群落的HI、S_(eq)、G、T_(90％)等指数均呈显著性相关。物种多样性(d)也在一定程度上反映出城市水体的不同污染程度。再次证明PFU微型生物监测方法的科学性,为生物监测提供了快速、经济、正确的新方法。     

微型生物群落eDNA-PFU监测

微型生物群落在水生态系统中起着至关重要的作用, 是水生态系统食物链的关键环节, 其结构和功能可以很好地反映不同生境的水质特征。《水质 微型生物群落监测 PFU法》是我国首个生物监测国家标准, 被证明是一种快速、经济、准确的监测方法。然而, 由于PFU法对专业知识要求较高、费时耗力且不易标准化, 严重阻碍了该方法进一步的推广与应用。近年来, 环境DNA(eDNA)技术的快速发展突破了微型生物形态鉴定的瓶颈, 能高效、准确地鉴定出水环境中包括微型生物在内的各种水生生物。为此, 文章提出微型生物群落eDNA-PFU法, 即基于eDNA技术改进的PFU法, 对微型生物群落进行监测。为了对eDNA-PFU法进行验证, 文章针对武汉东湖水体中的原生动物群落开展了预实验, 结果表明eDNA-PFU法较传统PFU法覆盖度与灵敏度均更高, 可以真实、全面、准确地揭示水体中微型生物群落结构特征。因此, 基于eDNA-PFU法的微型生物群落监测有望为湖泊、河流、水库等水体的生态考核提供新一代的生物监测标准。     

用PFU原生动物群落进行生物监测的研究

应用PFU法收集微型生物群落,监测鸭儿湖的农药污染。原生动物对五个氧化塘内农药废水的毒性反应,可用群集过程来表示,无论室内或是野外试验,结果基本一致。其中微型生物群落的结构参数有原生动物种类组成和种数、叶绿素a含量、水细菌数量;功能参数有反映原生动物群集过程中的S_(eq)、G、t_(90％)和微型生物的呼吸速度。功能和结构的参数均能较准确地反映出氧化塘系统的净化过程。PFU法可应用于预报污染物的生物效应浓度,初认为是一种经济、快速、正确的生物学监测方法。     

用PFU原生动物群落进行生物监测的研究

应用PFU法收集微型生物群落,监测鸭儿湖的农药污染。原生动物对五个氧化塘内农药废水的毒性反应,可用群集过程来表示,无论室内或是野外试验,结果基本一致。其中微型生物群落的结构参数有原生动物种类组成和种数、叶绿素a含量、水细菌数量;功能参数有反映原生动物群集过程中的Scq、G、t90％和微型生物的呼吸速度。功能和结构的参数均能较准确地反映出氧化塘系统的净化过程。PFU法可应用于预报污染物的生物效应浓度,初认为是一种经济、快速、正确的生物学监测方法。     

武夷山九曲溪水体营养水平与原生动物群落变化相互关系研究

2000年研究了武夷山九曲溪水体的营养状态与原生动物群落结构关系。发现并非水越清洁PFU原生动物种类就越多,这要决定于水体的营养状况。当水体是贫营养时,水越清洁,PFU原生动物种类反而会越少。研究结果表明,即使在低营养水平的水体中,PFU法一样能准确反映人类活动对当地水环境的影响。     

有机氯污染物在白洋淀PFU微型生物群落的富集

应用PFU法在白洋淀4个采样点采集微型生物群落,分析了PFU原生动物的群集过程,并利用气相色谱法首次在白洋淀微型生物群落中检测了OCPs和PCBs.结果表明:(1)在白洋淀的4个采样点的微型生物群落中均检测出OCPs和PCBs,表明白洋淀已受到上述污染物的污染.(2)河口附近的2个采样点微型生物群落中的POPs含量高于湖泊中心区.(3)从微型生物群落特征和群落中的POPs含量来看,府河污染对白洋淀的影响较大.应用PFU微型生物群落监测POPs污染物的优点在于取样方便,同一份样品既能获得生物群落结构的数据,又能获得化学污染物富集水平的数据.     

从浮游动物群落结构与功能的变化看府河—白洋淀水体的自净效果

本文报道了1993年5月、7月和10月在府河-白洋淀六个采样站浮游动物生态学特征及其与水质相互关系的调查研究结果。利用浮游动物群落结构的综合指标(种类组成差异,种类数目变化,个体数量变动,生物量分布,多样性指数d值的增减)和功能参数(PFU原生动物的群集速度)评价了府河-白洋淀水体的污染程度和自净效能。按照Margalef多样性指数d值的变化范围,把府河-白洋淀六个采样站的水质划分成不同的次序和等级。文中就如何控制污染,提高府河的自净效果,改善白洋淀的水质提出了具体措施和建议。       

生物操纵,营养级联反应和下行影响

理化因子和生物间的相互关系对生物群落的结构和生态系统功能的影响一直是生态学研究所关注的问题之一。在湖沼学方面,自６０年代大规模组织国际合作重点研究水体富营养化问题以来,氮、磷等植物营养物质与浮游植物和初级生产力之间的定量关系,对水质的影响的研究和一系...     

层次分析法对南水北调中线水源区的水质评价

层次分析法(AHP)是一种多指标多因素综合评价法,其理论内容深刻而表现形式简单,包括递阶层次结构模型、判断矩阵的建立及其求值、一致性检验和综合指数计算等运算过程.在南水北调中线水源区3个采样点进行了2a的水体浮游植物和9项理化指标的检测,并应用层次分析法通过季节4因素和6项理化指标对水质进行综合评价.结果表明:层次分析综合指数PI在3采样点有差异并且变化灵敏,渠首 (陶岔S1 ) PI=0.5697,水质属于污染;库心 (小太平洋S2 ) PI=0.3619,水质属于尚清洁;丹江入库上游 (大石桥S3 ), PI=0.7755,水质属于中污染;AHP分析结果与实际基本相符.根据结果分析认为:层次分析法做为综合评价法对水质评价有重要性,值得推广应用;丹江口水库是重要的水资源,但目前水质状况并不理想,因此做好水源区的长期生态监测,加强理论和技术研究,改善水质,极为重要.     

白洋淀原生动物群落多样性变化与水质关系研究

报道了大型浅水型湖泊原生动物群落变化与富营养化关系的研究,通过对华北平原最大淡水湖-河北白洋淀两个湖区9个采样站的初步调查,共鉴定出77种原生动物,其中43种为该湖首次记录：利用PFU原生动物群落结构和功能方法快速（两次实验的群集速度均为1d时间）监测了不同湖区的水质状况,水质分析及原生动物定性和定量调查结果表明,湖区Ⅰ（安州至枣林庄5个采样点）水体的污染程度明显大于湖区Ⅱ（圈头至端村4个采样站）,通过与20世纪50年代的调查资料比较,较好地反映了白洋淀富营养化的发展趋势。     

Characterization of protistan assemblages in the Ross Sea, Antarctica, by denaturing gradient gel electrophoresis

The diversity of protistan assemblages has traditionally been studied using microscopy and morphological characterization, but these methods are often inadequate for ecological studies of these communities because most small protists inherently lack adequate taxonomic characters to facilitate their identification at the species level and many protistan species also do not preserve well. We have therefore used a culture-independent approach (denaturing gradient gel electrophoresis [DGGE]) to obtain an assessment of the genetic composition and distribution of protists within different microhabitats (seawater, meltwater or slush on sea-ice floes, and ice) of the Ross Sea, Antarctica. Samples of the same type (e.g., water) shared more of the same bands than samples of different types (e.g., ice versus water), despite being collected from different sites. These findings imply that samples from the same environment have a similar protistan species composition and that the type of microenvironment significantly influences the protistan species composition of these Antarctic assemblages. It should be noted that a large number of bands among the samples within each microhabitat were distinct, indicating the potential presence of significant genetic diversity within each microenvironment. Sequence analysis of selected DGGE bands revealed sequences that represent diatoms, dinoflagellates, ciliates, flagellates, and several unidentified eukaryotes.     

Characterization of Protistan Assemblages in the Ross Sea, Antarctica, by Denaturing Gradient Gel Electrophoresis

The diversity of protistan assemblages has traditionally been studied using microscopy and morphological characterization, but these methods are often inadequate for ecological studies of these communities because most small protists inherently lack adequate taxonomic characters to facilitate their identification at the species level and many protistan species also do not preserve well. We have therefore used a culture-independent approach (denaturing gradient gel electrophoresis [DGGE]) to obtain an assessment of the genetic composition and distribution of protists within different microhabitats (seawater, meltwater or slush on sea-ice floes, and ice) of the Ross Sea, Antarctica. Samples of the same type (e.g., water) shared more of the same bands than samples of different types (e.g., ice versus water), despite being collected from different sites. These findings imply that samples from the same environment have a similar protistan species composition and that the type of microenvironment significantly influences the protistan species composition of these Antarctic assemblages. It should be noted that a large number of bands among the samples within each microhabitat were distinct, indicating the potential presence of significant genetic diversity within each microenvironment. Sequence analysis of selected DGGE bands revealed sequences that represent diatoms, dinoflagellates, ciliates, flagellates, and several unidentified eukaryotes.     

景观湿地夏季原生动物群落结构与水质关系

2011年夏季(6-8月)对杭州市境内一景观湿地西溪国家湿地公园进行采样, 共得原生动物样品21个。利用浮游生物研究方法对该湿地水域中原生动物的种类组成、群落特征、优势种分布、指示种及生物多样性指数进行了综合分析, 研究了该特征性水域中原生动物的群落特征与水质变动之间的关系。共鉴定原生动物84种, 隶属于3纲45属, 其中鞭毛虫纲61种, 纤毛虫纲14种, 肉足虫纲9种。优势种主要为隐滴虫(Cryptomonas)和眼虫(Euglena), 均属于鞭毛虫纲; 污染性指示种及Margalef等多样性指数均表明水质呈中度污染状态; 在原生动物功能类群中, 光合自养者最多, 腐生者、杂食者和捕食者相对较少; 主要理化指标中TN、TP和COD含量均较高, 且对原生动物群落的影响较大, 是造成群落变化的主要原因。综合评价结果揭示出, 西溪国家湿地公园水体目前仍处于中度污染状况。研究对湿地水域的污染原因进行了分析并提出了防治参考对策。       

Channeling of bacterioplanktonic production toward phagotrophic flagellates and ciliates under different seasonal conditions in a river

The objective of this study was to analyze the flux of biomass through the communities of bacteria and phagotrophic protists in the cold and warm conditions occurring seasonally in Butrón River. Bacterial and heterotrophic protistan (flagellate and ciliate) abundance was determined by epifluorescence direct counts; protistan grazing on planktonic bacteria was measured from fluorescently labeled bacteria uptake rates; and the estimate of bacterial secondary production was obtained from [³H]thymidine incorporation rates. The abundance of bacterial, flagellate, and ciliate communities was similar during cold and warm situations. However, we observed that estimates of dynamic parameters, i.e., secondary bacterial production and protistan grazing, in both situations were noticeably different. In the warm situation, grazing rates of flagellates and ciliates (bacteria per protist per hour) were, respectively, 7 times and 18 times higher than those determined in the cold situation, and the grazing rates of the protistan communities (bacteria per protists present in 1 ml of water per hour) increased up to 5 times in the case of flagellates and 42 times in the case of ciliates. Estimates of bacterial secondary production were also higher during the warm situation, showing a ninefold increase. The percentage of bacterial production preyed upon by flagellates or ciliates was not significantly different between the two conditions. These results showed that in the different conditions of a system, the flux of biomass between the trophic levels may be quite different although this process may not be reflected in the abundance of each community of bacteria, flagellates, and ciliates. Offprint requests to: J. Iriberri.     

Viruses and flagellates sustain apparent richness and reduce biomass accumulation of bacterioplankton in coastal marine waters

To gain a better understanding of the interactions among bacteria, viruses and flagellates in coastal marine ecosystems, we investigated the effect of viral lysis and protistan bacterivory on bacterial abundance, production and diversity [determined by 16S rRNA gene polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE)] in three coastal marine sites with different nutrient supplies in Hong Kong. Six experiments were set up using filtration and dilution methods to develop virus, flagellate and virus+flagellate treatments for natural bacterial populations. All three predation treatments had significant repressing effects on bacterial abundance. Bacterial production was significantly repressed by flagellates and both predators (flagellates and viruses). Bacterial apparent species richness (indicated as the number of DGGE bands) was always significantly higher in the presence of viruses, flagellates and both predators than in the predator-free control. Cluster analysis of the DGGE patterns showed that the effects of viruses and flagellates on bacterial community structure were relatively stochastic while the co-effects of predators caused consistent trends (DGGE always showed the most similar patterns when compared with those of in situ environments) and substantially increased the apparent richness. Overall, we found strong evidence that viral lysis and protist bacterivory act additively to reduce bacterial production and to sustain diversity. This first systematic attempt to study the interactive effects of viruses and flagellates on the diversity and production of bacterial communities in coastal waters suggests that a tight control of bacterioplankton dominants results in relatively stable bacterioplankton communities.     

Spatial distribution of protists in the presence of macroaggregates in a marine system

The spatial distribution of marine protistan communities in the presence of organic macroaggregates, formed from natural seawater, was studied in several microcosm experiments. The presence of macroaggregates had two main effects. First, the size of the communities of bacteria, flagellates and ciliates increased, as these communities were three orders of magnitude higher in the aggregates than in the microcosm water. In addition, it brought the diversification on the niches accessible to planktonic microorganisms, as three phases were formed: water, aggregates and aggregate-water interphase. Some of the detected protistan taxa were only found in the water, and therefore they can be considered as truly free-swimming protists. Others quickly colonised the aggregates, and finally, some of them showed a preference for the aggregate-water interphase. We discuss this spatial structuring of the protistan community on the basis of their feeding strategies and structural and behavioural characteristics.     

Benthic–pelagic coupling: a comparison of the community structure of benthic and planktonic heterotrophic protists in shallow inlets of the southern Baltic

1. The taxonomic composition, abundance and biomass of heterotrophic protists (ciliates, heterotrophic flagellates (HF), rhizopods and actinopods) in the sediment and water column of shallow inlets of the Southern Baltic was studied under a variety of environmental conditions during 1996–1997. A shallow, highly eutrophic station and a deeper, less eutrophic station were compared.
2. Community biomass ranged from 0.12 to 0.34 μg C cm?3 in the water column and from 1.5 to 105 μg C cm?3 in the sediment. Heterotrophic protists dominated zooplankton biomass at both stations (73% and 84% mean contribution), while they were of minor importance within the zoobenthos. Expressed per unit area, benthic biomass contributed a significant part (44% and 49%) to the total heterotrophic protistan community at both stations.
3. Although the methodology for counting ciliates and HF was focussed on a high taxonomic resolution, the results reveal some general trends in the distribution of heterotrophic protists: protozooplankton biomass was dominated by flagellates (80% mean biomass contribution) at the shallow station and by ciliates (73% mean biomass contribution) at the deep station. In the benthos at both stations, ciliates were the dominant protozoans, followed by the hitherto little‐studied rhizopods (25% and 35% mean biomass contribution) and flagellates.
4. The degree of benthic–pelagic coupling differed between taxonomic groups. Benthic and pelagic communities of ciliates showed little taxonomic overlap. In contrast, many heterotrophic flagellate species were found both in the benthos and in the pelagic. These benthic–pelagic species contributed significantly to the biomass of HF in the water column. The planktonic rhizopod community consisted of a subset of those species found in the benthos.
5. The abundance of benthic and pelagic protists was positively correlated at the shallow station, but taxonomic data indicate that the direct exchange between benthic and pelagic communities was only partly responsible.     

Protistan community patterns within the brine and halocline of deep hypersaline anoxic basins in the eastern Mediterranean Sea

Environmental factors restrict the distribution of microbial eukaryotes but the exact boundaries for eukaryotic life are not known. Here, we examine protistan communities at the extremes of salinity and osmotic pressure, and report rich assemblages inhabiting Bannock and Discovery, two deep-sea superhaline anoxic basins in the Mediterranean. Using a rRNA-based approach, we detected 1,538 protistan rRNA gene sequences from water samples with total salinity ranging from 39 to 280 g/Kg, and obtained evidence that this DNA was endogenous to the extreme habitat sampled. Statistical analyses indicate that the discovered phylotypes represent only a fraction of species actually inhabiting both the brine and the brine-seawater interface, with as much as 82% of the actual richness missed by our survey. Jaccard indices (e.g., for a comparison of community membership) suggest that the brine/interface protistan communities are unique to Bannock and Discovery basins, and share little (0.8–2.8%) in species composition with overlying waters with typical marine salinity and oxygen tension. The protistan communities from the basins’ brine and brine/seawater interface appear to be particularly enriched with dinoflagellates, ciliates and other alveolates, as well as fungi, and are conspicuously poor in stramenopiles. The uniqueness and diversity of brine and brine-interface protistan communities make them promising targets for protistan discovery.     

Succession of Protists on Estuarine Aggregates

Abstract Colonization by and succession of bacteria and bacterivorous protists on laboratory-made aggregates were determined over a period of 14 days during winter and spring in 1997. Aggregates were generated from natural water from the limnetic zone of the Elbe Estuary using a tilting tube roller system. Within 1 h after the beginning of the experiments, macroaggregates started to form. Aggregates reached a maximum size of 1 mm with a tendency toward large sizes at the end of the experiment after the 10th day. On the first day, high bacterial densities of more than 10⁹ cells ml⁻¹ were detected within the aggregates. The abundances of flagellates and ciliates within aggregates were also two or three orders of magnitude higher than in the surrounding water. Densities of aggregate associated organisms are comparable to those occuring in sediments. The first protistan colonizers on the aggregates were small heterotrophic flagellates, such as choanoflagellates and small euglenids. Later, beginning on the 4th day, small sarcodines and ciliates became abundant. The most abundant ciliates associated with aggregates were small species of the Hypotrichia, Cyrtophorida, and Hymenostomata. After 9 days, large omnivorous and carnivorous ciliates, such as large members of the Hypotrichia and the Pleurostomatida, occurred. In spring, large heterotrophic flagellates and amebae also appeared at this time. These findings indicated the existence of a succession of protists on newly formed aggregates and a microbial food net within the aggregates based on bacterial production. Additionally, most of the species observed during this study were adapted for living on surfaces. In natural environments they are more common in benthic than in pelagic environments. For them, aggregates are havens in the water column comparable to sediment communities. Received: 7 January 2000; Accepted: 15 May 2000; Online Publication: 28 August 2000