焦岗湖浮游甲壳动物群落结构的季节动态

2013年10月至2014年7月分季节对焦岗湖浮游甲壳动物群落结构动态进行调查,并探讨了影响浮游甲壳动物群落结构的环境因子。结果表明:焦岗湖共记录浮游甲壳动物17种,其中枝角类8属11种,桡足类5属6种;全湖枝角类的优势种为秀体溞(Diaphanosoma sp.)、矩形尖额溞(Alona rectangula)和脆弱象鼻溞(Bosmina fatalis),桡足类的优势种为跨立小剑水蚤(Microcyclops vaticans)和透明温剑水蚤(Thermocyclops hyalinus);浮游甲壳动物的密度和生物量呈现明显的季节变化,春、夏季较高,秋、冬季较低,年平均密度和年平均生物量分别为(196.30±313.75)ind·L-1和(1.80±3.18)mg·L-1;枝角类的密度和生物量的最高值分别出现在夏季[(28.53±55.91)ind·L-1]和春季[(0.61±0.70)mg·L-1],桡足类的密度和生物量的最高值均出现在夏季,分别为(31.47±51.09)ind·L-1和(2.82±4.58)mg·L-1;全湖浮游甲壳动物群落Shannon多样性指数的年平均值为1.07±0.81,最大值(1.74±0.46)出现在春季;典范对应分析(CCA)表明,与焦岗湖浮游甲壳动物群落结构的季节动态变化相关的重要环境因子为水温、p H、溶解氧、浮游植物生物量、营养盐等。     

太湖梅梁湾大型控藻围栏对浮游甲壳动物群落结构的影响

2005年对太湖梅梁湾大型鲢、鳙控藻围栏内外浮游甲壳动物群落结构的季节变化进行了监测.结果表明:围栏内外的环境因子、浮游植物生物量、浮游甲壳动物种类组成无显著差异.但鲢、鳙放养对浮游甲壳动物的生物量产生了较大的影响,围栏内浮游甲壳动物的总生物量和枝角类的生物量显著低于围栏外.总体上,枝角类各种类的生物量受鲢、鳙放养的影响程度大于桡足类的种类.太湖梅梁湾浮游甲壳动物的季节演替明显,大部分种类只是季节性出现.冬季和春季以溞(Daphnia sp.)和近邻剑水蚤(Cyclops vicnus)等大型种类为主,夏季和秋季以象鼻溞(Bosmina sp.)、角突网纹溞(Ceriodaphnia cornuta)和中华窄腹剑水蚤(Limnoithona sinensis)等小型种类为主.典范对应分析表明,透明度、温度和浮游植物的生物量是影响浮游甲壳动物季节变化的主要因素.     

新疆乌伦古湖浮游甲壳动物的季节演替及与环境因子的关系

通过2006年11月至2008年8月2周年8个季度的野外采样调查和室内分析,研究了新疆乌伦古湖浮游甲壳动物的季节演替格局及其与环境因子的相关性。结果表明,枝角类和桡足类的总种类数为25种,其中枝角类6种,桡足类19种。枝角类Shannon-Wiener指数2007年夏季和2008年夏季较高,2007年冬季最低;Pielou 指数2006年冬季最高;桡足类Shannon-wiener指数和Pielou指数除冬季较低外,其余三季较高。方差分析结果表明枝角类和无节幼体的密度与生物量呈现出显著的季节变动格局,其中,枝角类密度和生物量在夏秋季形成单一高峰,最大值出现在2007年夏,最大密度和生物量分别为2.12个/L和0.062 mg/L,而无节幼体密度和生物量形成春秋双高峰,其最大值出现在2007年春,密度和生物量分别为5.14个/L和0.015 mg/L,桡足类密度和生物量季节变化不明显。优势种的季节演替方面,象鼻溞和模式有爪猛水蚤全年形成优势,其他枝角类、哲水蚤和剑水蚤不同季节的优势种各异。经典范对应分析(CCA)结果表明,长刺溞等与水体中的pH值、SD呈正相关,与浮游植物生物量呈负相关;长额象鼻溞等与水深呈正相关,无节幼体等与水温也呈正相关性。     

浙江两类饮用水源地浮游动物种类组成及其类群相关性分析

于2009年7月至2010年4月,在浙江省选取了10个水库和10个河网饮用水源地,进行4个季节的浮游动物采样调查。记录浮游动物101种(轮虫60,枝角类24和桡足类17种)。水库和河网轮虫的优势种分别为角突臂尾轮虫(Brachionus angularis)和针簇多肢轮虫(Polyarthratrigla),枝角类分别为颈沟基合溞(Bosminopsis deitersi)和长额象鼻溞(Bosmina longirostris),桡足类均为温剑水蚤(Thermocyclops)。水库中有一些能指示良好生态或水质的指示性种类。水库枝角类与桡足类群落之间周年在丰度和生物量上均有极显著的正相关关系(P<0.01),轮虫与桡足类类群之间的相关性最弱;河网枝角类与桡足类在夏、秋、冬季有显著的正相关性(P<0.05)。浮游动物类群之间的相关性程度,以水库的秋季与河网的夏季为最高。轮虫与浮游甲壳动物的种类丰富度随着饮用水源水体透明度的变化呈现相反的变化趋势。     

淮河中游浮游甲壳动物群落结构的季节动态

2007年1-12月对淮河中游浮游甲壳动物群落结构的季节动态进行研究。共记录浮游甲壳动物24种, 其中枝角类8属13种、桡足类9属11种。枝角类在4月和9月形成两个峰值, 即(28.2±21.6) ind/L和(40.8±10.1) ind/L, 其优势种分别为僧帽溞 Daphnia cucullata和脆弱象鼻溞 Bosmina fatalis。捕食性桡足类-近邻剑水蚤Cyclops vicinus vicinus、广布中剑水蚤Mesocyclops leuckarti和台湾温剑水蚤Thermocyclops taihokuensis分别在4月、5月和6月形成较大的密度。汤匙华哲水蚤Sinocalanus dorrii和中华窄腹剑水蚤Limnoithona sinensis分别在5月和8月占优势。小型浮游植物(≤20 μm)生物量在4月达到最大值, 之后快速下降, 而较大型浮游植物(>20 μm)生物量从4月上升, 到7月达到最大值。典型冗余分析(RDA)显示, 溞属Daphnia的仲春下降与捕食性桡足类(尤其是近邻剑水蚤)的摄食压力、浮游植物生物量的季节变化密切相关。       

长江口南北支浮游甲壳动物的比较及南水北调工程影响预测

南水北调东线、中线工程实施后将给长江口水生生物的生态环境带来影响.2005年秋季和2006年春季,对长江口南、北支浮游甲壳动物进行了2航次的调查.调查区域从长江口徐六径至河口 50号灯标,全长181.8 km,自西向东江面宽由约5.7 km扩展为约90km,平面形态呈扇形分布,设立3个断面14个调查采集点.采集到浮游甲壳动物共23科37属54种,其中枝角类6科8属15种,桡足类17科29属39种;秋季种类数多于春季,北支桡足类种类数多于南支;平均总密度为9.10 ind·L-1,平均总生物量为0.1179 mg·L-1,以桡足类为主;北支Ⅲ断面的现存量远远高于南、北支其他断面;长额象鼻溞、简弧象鼻溞为优势枝角类;中华华哲水蚤、汤匙华哲水蚤、球状许水蚤、广布中剑水蚤为优势桡足类.文中还对长江口南、北支浮游甲壳动物的总体水平及时空分布、南水北调对浮游甲壳动物的影响进行了分析.     

巢湖春夏季节浮游甲壳动物群落演替的围隔实验研究

为研究巢湖浮游甲壳动物春夏季节的群落演替规律,于2012 年2 月19 日至2012 年7 月24 日（22 周）在巢湖进行了围隔实验。共设置三个处理组（即A 组：鲢鱼+营养盐;B组：鲢鱼+鳙鱼+营养盐;D 组：团头鲂+营养盐）和一个对照组（即C组：不添加鱼类和营养盐）。实验共记录浮游甲壳动物14 属21 种,其中枝角类9 属12 种,桡足类8 属9 种。透明溞（Daphnia hyalina）是春季所有围隔的优势种。春季浮游植物生物量和叶绿素a 浓度均处于较低水平。夏季以小型枝角类、大型中镖水蚤 （Sinodiaptomus sarsi）和剑水蚤占优势,其密度在围隔A、B和C中较低。夏季所有围隔中的Daphnia 种群均消失。在没有蓝藻水华和滤食性鱼类存在下,大型枝角类Daphnia 仍然被小型枝角类和桡足类所取代。结果显示,鱼类和营养盐共同决定了巢湖围隔浮游甲壳动物群落结构的季节变化。春季较高的Daphnia 种群密度也是巢湖Daphnia 仲夏消失的重要原因。     

鄱阳湖浮游甲壳动物群落结构特征

鄱阳湖是中国第一大淡水湖,具有"丰水为湖,枯水为河"的独特特点。为探讨鄱阳湖浮游甲壳动物群落结构及其时空分布的特征,于2009年全年采集其不同季节、不同水位期的浮游甲壳动物样品进行定量分析。结果显示,鄱阳湖浮游甲壳动物群落结构总体与河流浮游甲壳群落具有相似性。无节幼体、象鼻溞、剑水蚤等河流优势类群在鄱阳湖浮游甲壳动物中占优势;而哲水蚤和溞属仅在低水位季节占优势,枝角类丰度仅在高温、高水位、流速缓的季节高过桡足类。丰水期浮游甲壳动物平均丰度和生物量远远高于枯水期,可达枯水期的50倍,差异极其显著(P0.01)。温度和水位变化引起的环境因子改变是导致鄱阳湖浮游甲壳动物发生季节演替的主要原因;而营养盐对浮游甲壳动物的影响并不显著。空间上浮游甲壳动物群落构成明显不同,年均丰度最高和最低的点均出现在河口地区。因此:对于换水周期短,水交换速率快的水体,应该充分考虑水文条件对生物的影响。     

一座热带浅水水库敞水区浮游甲壳动物群落结构

为了解热带中小型浅水型水库枯水期浮游动物群落组成与结构稳定性,于2006至2007的三个枯水期,对位于我国雷州半岛甘村水库敞水区进行了每周一次的高频采样,主要以个体大小作为变量分析了浮游甲壳类动物的群落结构的组成.三次枯水期采样中,敞水区中只检测到枝角类4种和桡足类4种.浮游甲壳类的体长范围多集中在400～700μm之间.枝角类的优势种为模糊秀体溞平均体长为533μm,桡足类成体优势种台湾温剑水蚤的平均体长为787μm,无节幼体和剑水蚤桡足幼体丰度与生物量也相对较高.水库浮游甲壳类种类数和丰度的峰值均出现在体长为300～400μm和400-500μm两个等级内.浮游甲壳类的种类和数量均是以小个体为主,除了营养水平还与水体中的捕食压力紧密相关,鱼类的捕食对于浮游甲壳类群落结构的形成作用显著.     

一座热带中型水库浮游甲壳动物种类多样性与群落结构季节变化

松子坑水库是位于深圳市的一座调水型的中型水库, 水体处于中营养状态, 具体热带中型水库的典型特征。为了解该类水库的浮游甲壳类动物群落特征, 于 2012 年 2 月-2012 年 12 月对该座水库的浮游甲壳类进行了逐月采样。研究主要分析浮游甲壳类的种类组成、个体体长、丰度和生物量的季节变化特征, 以及水库浮游甲壳类动物的群落结构变化及其影响因子。共检出甲壳类浮游动物 16 种 , 其中桡足类 5 种 , 枝角类 11 种 , 具有较高的多样性。桡足类主要优势种为钩指复镖水蚤、温中剑水蚤和右突新镖水蚤, 枝角类以长额象鼻溞、颈沟基合溞和奥氏秀体溞等小型个体为优势种。同时还检测到了盔型溞以及大型枝角类理查德薄皮溞, 反映出该水库相对较低的捕食压力。同一种类丰水期的平均体长显著小于枯水期 ; 丰水期的桡足幼体/成体比较低 , 枯水期在种群发育的重要阶段。温度和捕食是影响该水库浮游甲壳类群落组成和多样性的重要因素, 浮游甲壳类动物群落结构具有相对稳定性。     

Cyanobacteria dominance influences resource use efficiency and community turnover in phytoplankton and zooplankton communities

Freshwater biodiversity loss potentially disrupts ecosystem services related to water quality and may negatively impact ecosystem functioning and temporal community turnover. We analysed a data set containing phytoplankton and zooplankton community data from 131 lakes through 9 years in an agricultural region to test predictions that plankton communities with low biodiversity are less efficient in their use of limiting resources and display greater community turnover (measured as community dissimilarity). Phytoplankton resource use efficiency (RUE = biomass per unit resource) was negatively related to phytoplankton evenness (measured as Pielou's evenness), whereas zooplankton RUE was positively related to phytoplankton evenness. Phytoplankton and zooplankton RUE were high and low, respectively, when Cyanobacteria, especially Microcystis sp., dominated. Phytoplankton communities displayed slower community turnover rates when dominated by few genera. Our findings, which counter findings of many terrestrial studies, suggest that Cyanobacteria dominance may play important roles in ecosystem functioning and community turnover in nutrient‐enriched lakes.     

Physico-chemical limnology and plankton dynamics of Mazvikadei,a tropical reservoir in Zimbabwe

The limnology of Mazvikadei Reservoir, northern Zimbabwe, was investigated in 2015 to determine whether it had changed since filling in 1990. The reservoir is characterised by low algal biomass, low nutrients (i.e. N and P) and high water clarity/transparency. Fifty-four species of phytoplankton were recorded, comprising Bacillariophyta, Chlorophyta, Cyanophyta, Desmids, Dinophyta and Euglenophyta. Chlorophyta numerically dominated in the hot dry season, whereas Bacillariophyta, Desmids, Dinophyta and Euglenophyta dominated in the cool dry season. Species richness was highest at the onset of the cool dry season, in response to high nutrient concentrations. Phytoplankton abundance and composition were significantly correlated with temperature, nitrates and total nitrogen. Nineteen zooplankton species were recorded, including Copepoda, Cladocera and Rotifera. Overall, Cladocera were numerically dominant and became most abundant during the cool dry season. Rotifers and copepods dominated during the hot dry season. The zooplankton abundance was correlated with reactive phosphorus and phytoplankton abundance. The trophic state of Mazvikadei Reservoir seems to have stabilised and to have assumed the physico-chemical characteristics and plankton community typical of an oligotrophic lake.     

The impact of planktivorous flsh on the structure of a plankton community

SUMMARY. 1. The abundance of pianktivorous juvenile yellow perch, Perca flavescens , was manipulated in three 750 m³ enclosures in a eutrophic lake.
2. There was a significant negative relationship between fish and zoopiankton biomasses. At high fish densities the zooplankton community was dominated by small filter-feeding cladocera. primarily bosmi- nids. At low fish densities the zooplankton community was dominated by large filter-feeding cladocera, primarily daphnids.
3. There was no significant relationship between zooplankton and phytoplankton biomasses when considered over the whole experiment but there was a trend towards lower phytoplankton biomass in the enclosure dominated by daphnids during mid-summer.
4. We conclude that although planktivorous fish have a strong negative impact on zooplankton community biomass and size structure, the relationship at the next lower trophic level, zooplankton and phytoplankton, is much weaker. Therefore, the biomanipulation of planktivorous fish populations as a management technique to control phytoplankton abundance is largely ineffective.     

How important is the crustacean plankton for the maintenance of water clarity in shallow lakes with abundant submerged vegetation?

• 1 We measured the abundance and biomass of filter‐feeding microcrustacean zooplankton and calculated their grazing impact on phytoplankton biomass during summer in five shallow, mesotrophic to eutrophic lakes. For three of the lakes data exist both from years with dense submerged vegetation and low turbidity (the clearwater state), as well as from years characterised by sparse vegetation and high turbidity (the turbid state). In the other two lakes data are available only for clearwater conditions.
• 2 In all lakes conditions of dense vegetation and clear water coincided with a low abundance of crustacean plankton during summer. In the three lakes that shifted, the calculated biovolume ingested by crustacean plankton (filtering rate) was 3–11 times lower during clearwater conditions compared with turbid conditions. Because phytoplankton biomass was lower during clearwater conditions, however, daily grazing pressure from microcrustacea (expressed as percentage of phytoplankton biomass) did not differ between states. In three of the five lakes, grazers were estimated to take less than 10% of the phytoplankton biomass per day, indicating filtration by zooplankton was not the most important mechanism to maintain clearwater conditions.
• 3 High densities of Cladocera were found in three of the lakes within dense stands of Charophyta. However, these samples were dominated by plant‐associated taxa that even during the night were rarely found outside the vegetation. This indicates that plant‐associated zooplankton has no major influence on the maintenance of water clarity outside the vegetation.
• 4 Spring peak abundance of Cladocera was observed in three of the lakes. In two of these, where seasonal development was studied in both the clearwater and the turbid state, spring peaks were lower during the clearwater state.
• 5 Predation, low food availability or a combination of both may explain the low zooplankton densities. Phytoplankton may be limited by low phosphorus availability in the lakes dominated by Charophyta. Our results indicate that the importance of zooplankton grazing may have minor importance for the maintenance of the clearwater state in lakes with dense, well‐established submerged vegetation.

     

Observations on the plankton of some Costa Rican lakes

We sampled 30 lakes in Costa Rica in the wet season (July–August) of 1991 for phytoplankton (with integrated and whole water samples), and 17 for zooplankton (with net tows). Taxa of plankton and community richness were poorly related to geography, morphology, chemistry, and other biota. Neither the zooplankton nor the phytoplankton appeared to influence the composition of the other, and neither were apparently influenced by the presence of fish.Phytoplankton richness reflected primarily sampling method, but also tended to decrease with elevation and with Secchi disk depth, and tended to increase with pH and alkalinity. Chlorophytes were the most abundant division in 14 lakes; these lakes tended to be unstratified, turbid, and located at higher elevation. Diatoms were common in 4 of the 7 lakes with elevated silica (over 30 ppm). Each lake showed at least a 3 : 1 dominance by copepods, cladocera, or insect larvae. Copepods dominated 7 of the 17 lakes, most of which were shallow, turbid, and had low alkalinity. Cladocera dominated 7 lakes that were typically deeper and located at low-to mid-elevations. Insect larvae dominated two small, turbid lakes.     

Can a community of small-bodied grazers control phytoplankton in rivers?

1. Phytoplankton, zooplankton and grazing were monitored throughout the growing season for three years (1994–96) in the Belgian section of the River Meuse.
2. A size structure analysis of the algal community shows that there was a summer shift toward larger algal units, following a decline in phytoplankton biomass. These changes occurred after an increase in zooplankton biomass and diversity.
3. Daily filtration rates of grazers ranged from 1 to 113% day^–1 and maxima were observed during the summer period. Higher rates tended to correspond with peaks of rotifer biomass. A decline in total phytoplankton biomass within two weeks followed the increase in zooplankton biomass and filtration rate. A rapid biomass recovery was then observed, along with a shift of the algal community toward larger units. When grazing activity was not sustained, due to zooplankton fluctuations, the change in phytoplankton size structure was less marked.
4. We suggest that the composition of the phytoplankton community of large rivers may at times be controlled by grazers. However, such biotic interactions can take place only when physical constraints are reduced, i.e. when discharge is low, and when increased transfer time, high temperature and availability of grazeable algae allow high zooplankton biomass.     

鄱阳湖不同水文期浮游生物群落结构特征和影响因素及水质评价

为阐明鄱阳湖不同水文期浮游生物群落结构特征及其影响因素, 研究于2017年8月(丰水期)和12月(枯水期)在鄱阳湖湖区典型水域设置5个采样点进行浮游生物采样调查。研究期间共鉴定浮游植物8门75属186种, 丰水期与枯水期均以硅藻门和绿藻门为主。共鉴定浮游动物4类76种, 丰水期与枯水期均以原生动物和轮虫为主。方差分析显示: 浮游植物密度与生物量在不同水文期之间的差异均为极显著(P<0.01), 浮游动物丰水期密度高于枯水期, 但无显著差异(P>0.05), 浮游动物生物量(P<0.05)在不同水文期差异显著。冗余分析(RDA)显示: 丰水期透明度和浮游生物呈显著负相关关系, 电导率和浮游生物呈显著正相关。透明度、电导率与营养盐是影响丰水期浮游生物群落结构的主要环境因素, 枯水期水温和溶解氧是驱动鄱阳湖浮游生物群落生态分布的主要环境因素。基于Shannon-Wiener(H′)、Margalef(d)和Pielou(J)等生物多样性指数的水质评价结果表明: 鄱阳湖研究区域水质状态处于寡污-中污之间。研究揭示了2个水文期对通江湖泊浮游生物的影响: 季节变化不改变湖泊浮游生物的物种组成及优势种, 但显著影响浮游生物的丰度及多样性。     

Two types of maternal care for juveniles observed in Caprella monoceros Mayer, 1890 and Caprella decipiens Mayer, 1890 (Amphipoda: Caprellidae)

Spatial and seasonal patterns in phytoplankton and zooplankton communities of Lake St. Clair from June through September, 1984 are described. Phytoplankton biomass averages 586 µg l^-1 with the Diatomae and Chrysophyceae predominating. Zooplankton biomass averages 663 µg l^- with small bosminid Cladocera being the most abundant organisms. Lake St. Clair zooplankton biomass is second only to that of Lake Erie amongst the St. Lawrence Great Lakes. Biomass size spectra are typical in structure for mesotrophic lakes but low explained variance in the annual normalized spectrum is indicative of a perturbed system. Since 1972/1973 there appears to have been a slight decrease in zooplankton abundance in the lake accompanied by a shift from dominance of rotifers to dominance of cladocerans. We hypothesize that high flushing rate and seasonal variability coupled with contaminant loadings have resulted in a plankton community reduced in taxonomic diversity and dominated by small-bodied species.     

亚热带大型水库——新丰江水库的浮游生物群落特征

于2000年丰水期和枯水期,调查了新丰江水库的浮游生物群落结构,新丰江水库处于贫营养状态,浮游生物密度和生物量均较低。浮游植物34种,丰水期以蓝、绿藻为主,分别占总数量的31.7%和36.8%,蓝藻、绿藻细胞微小,chl.a量未占优势;枯水期硅藻为优势种群,占63.9%,浮游生物22种,丰水期轮虫为主,占65.3%,枯水期桡足类占81%,丰水期动物密度较高,但丰水期以轮虫如螺形龟甲轮虫为主,枯水期以无节幼体,桡足幼体及广布中剑水蚤居多,因此枯水期生物量高于丰水期。