黄河流域干旱区湖泊冰封期浮游植物群落结构特征及影响因子研究

为研究黄河流域上游干旱地区湖泊冰封期浮游植物群落结构及影响因子,选取干旱区典型湖泊——乌梁素海、奈伦湖为研究对象,于2019年3月冰封期进行采样调查,分析冰封期湖泊营养状态特征与浮游植物物种组成、数量及多样性指数,利用冗余分析(RDA)揭示浮游植物物种与环境因子影响关系,并运用方差分解分析主要环境因子的影响程度。结果表明,冰封期水体浮游植物共6门21属29种,其中硅藻12属16种,占据全部物种的55.2%;不同采样点浮游植物数量、生物量变化范围为3.2×10~4～1.4×10~5cells/L和0.047～0.328 mg/L,主要优势种以尖针杆藻(Synedra acus)、美丽星杆藻(Asterionella formosa)、双头辐节藻(Stauroneis anceps)等硅藻为主;不同浮游植物多样性指数H′范围0.70～1.74,介于中度污染,表明研究湖泊浮游植物多样性相对较差;不同采样点位之间浮游植物群落相似性主要处于Ⅱ、Ⅲ等级,即极不相似和轻度相似,表明各采样点之间浮游植物群落结构具有较为明显的差异。RDA分析结果表明,影响浮游植物物种分布的主要环境因子水温、总氮和硝酸盐;方差分解分析进一步显示,营养因子(总氮和硝酸盐)单独对优势种物种分布解释量达到33.66%,理化因子(水温)单独对优势种物种分布解释量达到13.24%。     

洱海浮游植物种类组成及多样性分析

通过2014—2015年洱海浮游植物监测数据,运用Shannon-Wiener指数和Pielou均匀度指数进行分析计算,解析洱海浮游植物群落的组成、分布,以揭示洱海水体浮游植物多样性指数、均匀度指数的变化规律。分析表明洱海多样性指数值、均匀度指数值分别在2~4、0.17~0.73之间,总体评价洱海地区属于中度污染。洱海藻细胞密度变化表现为秋季高,春季低,夏冬季平的特点,冬、春季同期藻种多样性指数、均匀度指数高,物种丰富,水质良好;夏季藻细胞密度、多样性及水质变化则反之。研究还发现浮游植物藻细胞密度高,藻类多样性会降低,极易引起水华;同时,蓝藻水华爆发又容易引起浮游植物多样性指数、均匀度指数的降低,造成浮游植物藻种相对单一。     

白洋淀浮游生物群落结构的季节变化及其与环境因子的关系

浮游生物是水生态系统的重要组成部分,由于其对水环境状况的敏感性常被用来作为水环境优劣的指示生物。为研究白洋淀浮游生物群落特征及其与环境因子的关系,于2018年春季(5月)、夏季(8月)和秋季(10月)分别对白洋淀淀区5个采样点的浮游生物及环境因子进行调查分析,并采用Pearson相关性分析法分析白洋淀浮游生物群落结构变化和主要环境因子的相互关系。结果表明:根据TP、NH_3-N、COD_(Mn)、TN等水质参数浓度值进行水体质量评价,白洋淀水体夏季为Ⅴ类水,春季和秋季为Ⅳ类水。白洋淀研究区域共检出浮游植物6门74种,浮游动物3门22种。白洋淀浮游生物的群落结构季节间变化显著,两类浮游生物夏季丰度均达到最大值。浮游植物春、夏季以蓝藻门和绿藻门占绝对优势,秋季则出现硅藻门、裸藻门、甲藻门和隐藻门等优势类群。浮游动物在各个季节均以轮虫为优势类群。根据浮游生物群落特征指数进行水质类别分析,白洋淀在不同季节大部分指数显示为中污染。浮游生物多样性指数反映的水质污染状况与理化因子水质评价结果与季节变化趋势相对一致。浮游植物多样性指数与TP、COD_(Mn)和DO的相关性较大,浮游动物多样性指数与COD_(Mn)、NH_3-N和TN相关性较大。     

黄河源区浮游植物群落特征研究

为初步掌握黄河源区藻类的概况,于2016年7月(夏季)和10月(秋季)对河源源区重点湖泊河段开展了浮游植物系统调查研究。调查记录浮游植物7门52种,以硅藻门(21种)和绿藻门(18种)为主,优势种多属硅藻门中的贫营养或中营养型种类。调查发现浮游植物密度整体较低,介于6.90×10~4～1.17×10~6 cells/L之间,夏季明显高于秋季,湖泊明显高于河流。通过对浮游植物的密度、Shannon-Wiener多样性指数及Pielou均匀度指数的分析认为,黄河源区水质介于极贫营养水平到贫中营养水平之间,水生态环境状况整体良好。研究成果可为黄河源区水生态保护提供理论依据和数据支撑。     

官厅水库浮游植物多样性及演变趋势分析

2011年6、7月,分别对官厅水库样点进行了浮游植物样品和有机分析样品采集,以形态分类方法对浮游植物显微镜检分析,以液相色谱法对微囊藻毒素浓度进行了分析.结果表明,官厅水库本次调查共鉴定出浮游植物4门18属,种类最多的为绿藻门9属,浮游植物总藻细胞密度为508.09万个/L,蓝藻门和绿藻门占总藻细胞密度的96.71％,为水库浮游植物的优势门类;平裂藻属、卵囊藻属和栅藻属藻细胞密度为37.2万个/L,占浮游植物藻细胞密度的82.98％,为官厅水库浮游植物的优势属.官厅水库7月浮游植物叶绿素a浓度为12.67μg/L,浮游植物Shannon-Wiener多样性指数为0.75,Margalef指数为1.1,Simposon多样性指数为2.95,说明浮游植物群落结构较简单,富营养化程度较高.6月微囊藻毒素LR和囊藻毒素RR浓度分别为29.27、4.04 ppt,浓度值均较低.官厅水库浮游植物优势种类在1956年为硅藻门种类逐渐演变成蓝藻门种类,藻细胞密度从1956-2007年呈现逐年上升趋势,2011年7月藻细胞密度较近年来年平均藻细胞密度有所降低.     

岳城水库浮游植物多样性现状分析

2017年4月(非汛期)和8月(汛期),对岳城水库浮游植物群落结构进行调查研究,通过Shannon生物多样性指数分析,探讨岳城水库浮游植物群落结构特征,以期为岳城水库以及其它同类型水体的水质监测及有效管理提供参考。非汛期调查共发现浮游植物7门38种,汛期调查发现浮游植物4门25种;非汛期浮游植物密度平均值为0.57×106个/L,汛期浮游植物密度平均值为12.26×106个/L;非汛期浮游植物生物多样性指数为0.45~0.98,汛期浮游植物生物多样性指数为0.53~0.69。浮游植物类群和Shannon多样性指数调查分析结果表明,岳城水库水体已经处于富营养化状态。     

白洋淀浮游动物生物多样性及水生态评价

为研究白洋淀浮游动物生物多样性和水生态状况,2012年6月和10月对浮游动物进行了采样调查。结果表明:白洋淀共鉴定出浮游动物37种,其中枝角类最多,占总数的51.4%;各监测站点浮游动物密度为2480~7580ind/L,平均密度4160 ind/L;生物量为0.46~1.81 mg/L,平均生物量1.24 mg/L。Margalef多样性指数为1.83~3.51。浮游动物损失指数表明,整个白洋淀地区浮游动物状况相对于历史数据均有不同程度变差。用浮游动物多样性指数评价水质状况,白洋淀处于中度污染水平;综合浮游动物生物量评价水体营养级别标准,考虑到富营养化指示物种的存在,综合评价白洋淀水体处于富营养状态。     

白马湖浮游植物分布特征及其与环境因子相关性分析

为掌握白马湖生态状况识别主要生态问题,2014年、2016年和2017年在白马湖湖区布设11个点位,监测分析该湖浮游植物群落结构的时空变化和水质情况。结果表明,2014年共鉴定浮游植物119种,2016年共鉴定109种,2017年共鉴定114种,隶属于8门,主要优势种为小球藻(Chlorella sp.)、小环藻(Cyclotella sp.)、颗粒直链藻(Melosira granulata var. angustissima)、尖针杆藻(Synedra acus)、卵形金杯藻(Kephyrion ovale)、尖尾蓝隐藻(Chroomonas acuta)、链状伪鱼藻(Pseudanabaena catenata)和席藻(Phormidium sp.)。浮游植物丰度在夏季最高,冬季最低,在空间分布上西北部和中部较高,东北部和南部较低。并从Shannon-Wiener多样性指数、Pielou均匀度指数和SI污染指数3个指标评价不同年份湖泊的健康状况,白马湖为中-富营养(中度)水体。并对浮游植物优势种和环境因子之间进行Pearson相关性分析,结果表明,温度是影响浮游植物丰度的主要因子。     

阳宗海浮游植物群落与营养状态评价

为掌握阳宗海浮游植物群落结构与水质状况,2009、2010年对阳宗海进行了全年调查分析,共发现浮游植物8门70属,群落组成以绿藻、蓝藻、硅藻为主;以蓝藻门的微囊藻、拟鱼腥藻、尖头藻、束丝藻4属藻类交替出现成为优势种群.两年的藻细胞密度变化幅度为192.47～9 528.35万个/L,2009、2010年平均密度分别为1 498.55、5007.64万个/L,藻细胞密度有上升趋势.每年的夏季、秋初气温较高,易形成2个藻类高峰.应用卡尔森营养状态指数法、优势种评价法进行评价,结果表明阳宗海水体处于中营养状态,营养状态指数值有缓慢增加的趋势,中营养程度有加重的趋势.     

同沙水库夏季浮游植物群落结构特征及影响因子分析

为评估同沙水库水生态状况，于2021年8月在同沙水库开展了浮游植物样品的采集和水质状况的调查。依据Shannon-Wiener多样性指数(H′)、Pielou均匀度指数(J)和浮游植物密度对水质和水体营养状态进行评价，采用Spearman相关性分析浮游植物与环境因子间的关系。结果表明：本次采样调查共鉴定出浮游植物6门48种，绿藻门种类数最多，占47.9%,蓝藻门次之(27.1%),优势种以蓝藻门微小平裂藻(Merismopedia tenuissima)、点形平裂藻(Merismopedia punctata)、微囊藻(Microcystis)为主，蓝藻门浮游植物密度、生物量均高于绿藻门。夏季同沙水库各采样点水质类型均为清洁—寡污染型，水体营养状态为富营养型，pH和NH⁺₄-N是影响同沙水库浮游植物群落结构的主要环境因子。     

Planktonic indicators of water quality: A case study in the Amacuzac River Basin (State of Morelos,Mexico)

Planktonic organisms are good indicators of water quality but are rarely used in Mexican riverine studies in spite of the high level of contamination in these lotic waters. In this study, we focused on the plankton of the river Amacuzac in Mexico and a large saline waterbody, Lake Tequisquitengo, which is located in the Amacuzac river basin. We collected samples at three sites in the River Amacuzac and one at Lake Tequisquitengo from May 2015 to March–April of 2016. We analysed the physicochemical variables, coliform bacteria, and biological oxygen demand levels. We also quantified phytoplankton and zooplankton. Our results indicate that the study sites are mesotrophic with high densities of diatoms and cyanobacteria. Among the zooplankton, the dominant organisms were rotifers. The constancy of planktonic taxa was high in the lake but low in the river. The Descy index ranged from 2.9 to 4.5 in the river and from 4.0 to 5.0 in the lake. The saprobic index shows that the system is β‐mesosaprobic. The species diversity was higher in the river than in the lake. Our study shows that plankton can efficiently be used to evaluate the water quality in rivers and lakes.     

陈桥东湖浮游生物群落结构特征及水质评价

陈桥东湖是新乡黄河湿地鸟类国家级自然保护区中部实验区的常年集水区之一,是许多珍稀鸟类的繁殖及栖息地,具有重要的生物多样性保护和潜在的科学研究、生态旅游价值。为了解陈桥东湖浮游生物群落结构特征及水质状况,于2017年1月、4月、7月和10月对陈桥东湖进行浮游生物采样调查,并利用浮游生物多样性指数评价水质状况。结果共发现浮游植物有8门67属118种,其中绿藻47种,种类最多,占39.83%;其次是硅藻,有35种;甲藻最少,只有2种。各采样点浮游植物丰度变化范围为(2.52~39.7)×10⁶ cells/L,全年主要优势门类为硅藻、绿藻和蓝藻。共发现浮游动物34种,轮虫种类最多,共21种,占61.76%;丰度变化为68~1 342 cells/L。全年轮虫为主要优势种类,轮虫滤食者RF为主要浮游动物功能群。浮游生物多样性指数结果显示陈桥东湖水体整体呈中度污染状况,且夏季最差,冬季相对较好,与水体理化指标调查结果一致。研究成果可为新乡黄河湿地水环境保护及生态修护提供参考依据。     

Temporal patterns in phytoplankton,zooplankton and fish composition,abundance and biomass in Shirati Bay,Lake Victoria,Tanzania

Shirati Bay is among the important breeding and nursery sites for major fish species in Lake Victoria. Weekly samplings were conducted to assess the temporal patterns in phytoplankton, zooplankton and fish composition, abundance and biomass in relation to prevailing water quality parameters. The study also determined the influences of plankton dynamics and water quality on the fish catch composition and biomass. It was hypothesized that temporal patterns in the composition, abundance and biomass in the plankton in the bay are controlled by water quality parameters that, in turn, affect the composition and biomass of fish catches. The phytoplankton comprised mainly cyanophytes and bacillariophytes, while the zooplankton were dominated by copepods. The heavy rain season exhibited a significantly higher plankton abundance and biomass than the dry season. The plankton abundances in both seasons exhibited significant positive correlations with water temperature and transparency. The phytoplankton community was controlled by calanoid and cyclopoid species. At higher trophic levels, Lates niloticus juveniles, Oreochromis niloticus juveniles and haplochromines controlled Cladocera and Cyclopoid copepods, while Tilapia rendalli juveniles controlled the Rotifera. This study revealed that Cyanophyta and Bacillariophyta are the dominant phytoplankton, whereas cyclopoids dominate the zooplankton species in the bay. These dominant plankton groups are partly controlled by rainfall, water temperature and transparency. Fish biomass, zooplankton and phytoplankton exhibit a typical predator–prey inverse relationship. Thus, evaluation of the plankton composition, abundance and biomass should be mandatory during fisheries stock assessments to effectively manage the fishery resources in the bay.     

Mass balance model of Lake Volta fisheries: The use of Ecopath model

A mass balance model of trophic interactions among ten key functional producer and consumer groups in Lake Volta was constructed using the Ecopath model to study the energy flows and species interactions in the lake. The present study was based on secondary and primary data on fish catch, diet composition, phytoplankton and zooplankton biomasses, collected in 2015 and 2016. Additional information on growth parameters of major species required for balancing the Ecopath model was obtained from sampling and FishBase. The functional groups were detritus, phytoplankton, zooplankton, benthos, prey fish, Tilapia, Bagrus, Chrysichthys, Alestes and Synodontis species. Four trophic levels were identified in the Lake Volta ecosystem, with the energy flow occurring mainly within the first three trophic levels. The calculated ecotrophic efficiency value of the primary producers (phytoplankton: 0.17; detritus: 0.22) indicated they were least exploited, compared to the secondary producers, zooplankton (0.80) and benthos (0.50). All secondary consumers had ecotrophic efficiency values higher than the primary producers, indicating they are exploited in the ecosystem. The main energy flows in the lake were from phytoplankton and detritus at trophic level I, and Bagrus species, the top predator, at a level of 3.30. The network analysis, illustrating a connectance index of 0.43 and an omnivory index of 0.06, in the lake system indicated the ecosystem is unstable, somewhat immature and still in a developing stage.     

The Phytoplankton Zooplankton Link in the Lake Ontario Food Web

Monitoring in Lake Ontario in 1970 and 1982 demonstrated that the zooplankton community was dominated by microzooplankton, which suggested a longer, perhaps inefficient food chain. In this study, annual monitoring of the offshore region of Lake Ontario between 1986 and 1992 was used to determine if microzooplankton were still dominant despite recent changes in nutrient loading and species introductions. Microzooplankton accounted for 49.7% of the total summer zooplankton biomass while small edible phytoplankton accounted for 67.0% of the biomass during the summer. By direct in situ measurement using a Haney grazing chamber, rather than size grazing relationships, the relative impact of micro- and mesozooplankton grazers on phytoplankton production during the summer of 1995 was evaluated. Microzooplankton filtration rates (%/d) for 1995 were significantly higher than mesozooplankton filtration rates. Zooplankton consumed only 17.5% /d of the primary production with microzooplankton grazing representing 69.8% to 93.2% of this amount. Microzooplankton are clearly still dominant and their consumption of primary production in Lake Ontario is low. The major pathway of energy transfer can not be through the classical phytoplankton > large zooplankton > planktivore > piscivore food chain but rather through the phytoplankton > microzooplankton and presumably predacious zooplankton and fish. The longer food chain is a result of the introduction of a size-selective planktivore, the alewive, which has decreased the length and presumably lowered the consumption rate of the entire zooplankton community. This structural impact, a longer food chain, theoretically creates a higher factor of biomagnification of organic chemicals for top-level predators along with lower rates of energy transfer within the food web and suggests lower fish production than in a shorter food web.     

长荡湖、滆湖、竺山湾藻类功能群结构组成与环境因子的关系

为研究太湖流域上游长荡湖、滆湖、竺山湾三大典型浅水湖泊藻类功能群结构组成与环境因子的关系,基于2019年2月至2020年10月水文、水质及浮游植物数据,采用Q指数、香农-维纳多样性指数、TLI综合富营养化指数分析了3个湖泊的水质状况,采用非度量多维尺度变换(NMDS)分析了浮游植物群落结构组成特征,采用冗余分析探讨了浮游植物功能群与环境因子的关系。结果表明：长荡湖和滆湖水质整体属于轻度富营养化,竺山湾除冬季外,均属于中度富营养化;长荡湖、滆湖、竺山湾分别有浮游植物7门61属96种、8门75属129种和6门53属124种,分别划分为9、10和11个优势功能群;3个湖泊藻类功能群变化的共同环境因子是水温、高锰酸盐指数和总磷,而总氮和氮磷比对3个湖泊功能群结构变化的作用并不明显。     

Biomanipulating the drinking water reservoir of Estonia's capital city: Prospects for success

The possibility of utilizing biomanipulation to improve the water quality of Tallinn's drinking water reservoir (Lake Ülemiste) was analysed on the basis of water quality data, test fishing by different methods, and earlier studies on aquatic plants, light climate and sediments. Eutrophic, polymictic Lake Ülemiste is characterized by a prevalence of high filamentous cyanobacteria biomass, rotifers in the zooplankton community, mature bream in the fish biomass, and a high density of planktivores (YOY perch). Several prerequisites for being a potential target for biomanipulation were identified, including (i) decreased external total phosphorus (TP) loading; and (ii) a sufficient stock of piscivorous fish in the lake. Prohibition of fishing should favour biomanipulation efforts. The potential for recolonization of macrophytes and large Daphnia species in Lake Ülemiste could be judged from historical data. The in-lake TP concentrations are within the limits that facilitate successful restoration. As phytoplankton biomass was significantly limited by phosphorus in Lake Ülemiste, its water quality improvement will be driven primarily by reduced nutrient concentrations, and then by zooplankton grazing. Internal TP loading and a new phytoplankton species community were assessed as major challenges for successful implementation of biomanipulation as a means of improving the water quality of Lake Ülemiste.     

Ecological implications of artificial mixing and bottom-sediment removal for a shallow urban lake, Lake Sheldon, Colorado

This paper describes the results of the investigation of a shallow urban lake before, and a second year after, restoration to determine the effects of aeration and bottom‐sediment removal on the trophic state and environmental variables controlling the lake's phytoplankton, macrovertebrates and zooplankton compositions. The anthropogenic eutrophic process of the lake is characterized by increased nutrient concentrations from urban run‐off inputs. This addition triggers a chain of events that start with a massive increase in the growth of primary producers, as these are generally growth‐limited by nutrients in freshwater ecosystems. Although the lake was artificially mixed, nuisance cyanobacteria were dominant as primary producers the second year after restoration, during the summers of 2004 and 2005, until this population collapsed and were replaced by diatoms after periods of high winds, rainfall and a decreased temperature. The absence of macrophytes in the main basin because of the removal of bottom sediment had a major effect on macroinvertebrates and zooplankton. Daphnia sp. was the dominant zooplankton species before restoration, being replaced by Bosmina sp., possibly because of the lack of refuge by macrophytes. As an alternative, Bosmina sp. used the surface blooms of cyanobacteria in summer as refuge from grazing by planktivorous fish. The greatest disturbance on the macroinvertebrate community richness and evenness was the decline of scrapers and shredders, because of the lack of macrophytes after removal of the lake bottom sediment.     

Assessment of threats to a Ramsar site from seafood processing operation effluents

Waterbodies receiving effluents from seafood processing plants might experience severe eutrophication. The present study was carried out to assess the impacts of effluent discharges on water quality and phytoplankton populations in the Vembanad‐kol Wetland, located adjacent to seafood processing industries. It was conducted in the Cherthala–Aroor–Edakochi coastal belt of Vembanad Wetland, India, a region containing many processing plants. The trophic status of the lake was assessed with the Carlton trophic state index. Hypereutrophic conditions were observed more in the interconnected channels than in the main waterbody. There was a dominance of Bacillariophyceae, followed by Chlorophyceae, Cyanophyceae and Dinophyceae. Bacillariophyceae, Chlorophyceae and Cyanophyceae were comparatively higher in the interconnected channels, whereas Dinophyceae was high in the main body of the lake. There is a shift in dominance from Chlorophyceae to Cyanophyceae in the interconnected channels, especially in the southern and central portion of the lake. There was a dominance of Cyanophyceae over Chlorophyceae, especially in the interconnected channels, being a characteristic of polluted water. Nitzschia sp and Navicula sp were abundant in the class Bacillariophyceae. The dominant species in the class Dinophyceae was Ceratium sp, which is known to proliferate in nutrient‐rich waters. The dominant members of the class Chlorophyceae were Ankistrodesmus sp and Scenedesmus sp. Furthermore, Oscillatoria and Phormidium were higher in number in the class Cyanophyceae, indicating the presence of pollutants of biological origin. Waste discharges from the seafood processing industry are a major factor contributing to an alarming rate of organic pollution and subsequent eutrophication in the lake. The results of the present study highlight that further expansion of the seafood industry in the Cherthala–Aroor–Edakochi coastal belt of Vembanad Lake is not desirable.     

张福河浮游植物群落结构及生态位特征

为了解张福河浮游植物群落结构特征,于2019年7月(夏季)、9月(秋季)和12月(冬季)进行3次调查与取样,利用改进的Levins生态位宽度和Petrailis生态位重叠指数测度浮游植物优势种的生态位.结果表明:共鉴定到浮游植物140种,其总平均密度大小顺序为秋季、夏季、冬季;优势种共16种,以硅藻门和绿藻门为主且多为...