Review of the fauna of Rotatoria,Cladocera, and Copepoda of the basin of the Anadyr’ River

The zooplankton composition is studied in the thermokarst, glacial and meteorite lakes, channels, former riverbeds, and hollows in the basin of Anadyr’. We found 174 taxa: 78, Rotatoria, 55, Cladocera, and 41, Copepoda. The most diverse is the lake fauna: 51 taxa of Rotatoria, 48, Cladocera, and 37, Copepoda. The thermokarst Lake Maiorskoe hosts 68 taxa: 31, Rotatoria, 14, Cladocera, and 23, Copepoda, wheras the cold ultraoligotrophic Lake El’gygytgyn features only one species of Cyclop of the group scutifer Cyclops neymanae Strel., and Rotatoria and Cladocera are present as allochtonous forms. The Copepoda illustrate the relations of the Anadyr’ fauna with those of Europe, North America, and Japan.     

Invertebrate zooplankton predator composition and diversity in tropical lentic waters

Invertebrate zooplankton predators are generally less diverse in average species numbers in tropical than in temperate lakes and reservoirs. Predatory Copepoda which comprise the majority of limnetic predators are particularly low in species numbers in the tropics. Predatory Cladocera are confined to the North Temperate zone. Chaoborus appears to be cosmopolitan. Among Rotifera, only the cosmopolitan predator Asplanchna occurs in tropical waters while the other common limnetic carnivorous genus Ploesoma is restricted to higher latitudes. Hydracarina, and insects besides Chaoborus, are generally restricted to the littoral and appear to be more diverse in the tropics. Lakes Awasa and Zwai, Ethiopia, are almost devoid of predators in the limnetic, which is invaded by a littoral chydorid Alona diaphana. Low diversity of lake types and low production of tropical zooplankton could restrict predator diversity too. Very low diversity of invertebrate predators in the limnetic and higher diversity in the littoral may characterize tropical lakes in contrast to temperate lakes, which have more invertebrate predators in the limnetic and perhaps relatively less in the littoral. Tropical zooplankton in freshwaters, appears to be a very immature community. Hence opportunistic species can readily invade the limnetic and even dominate in isolated situations as has been shown for Alona davidi, Hydracarina and some other unconventional forms.     

Structure and dynamics of zooplankton communities in the littoral zone of some North Carolina lakes

Species composition and seasonal, dynamics of zooplankton in the littoral zone were studied in three piedmont North Carolina lakes for one year. Nygaard's compound index indicated oligotrophic conditions in Belews Lake and eutrophic conditions in Salem Lake and Lake 150. A total of 32 species of zooplankton were found in the samples. Significantly fewer species of truely littoral zooplankton were present in the oligotrophic lake regardless of season (P < 0.05). Eutrophication appears to favor increased diversity in zooplankton of the littoral zone. Habitat heterogeneity, provided by a well developed littoral zone containing aquatic macrophytes, may be the major factor contributing to the maintenance of more taxa of zooplankton in eutrophic systems.Distinct taxa of Cladocera and Copepoda are present in the littoral zone, exhibiting seasonal dynamics that are largely different from the limnetic fauna. Such dynamics may result from predation by characteristically limnetic species of cyclopoid copepods which seek prey in the littoral zone. The numerical and seasonal abundance of predators and prey are inversely related and the true littoral taxa, represented in the present study by the genera Alona, Chydorus, Pleuroxus, Sida, Simocephalus, and Eucyclops, contained no predaceous species. The seasonal dynamics of these genera are very similar even in widely separated geographical regions, indicating that the factor(s) responsible operate independently of climatic and chemical variables. Intrazooplankton predation appears to be a more plausable explanation than segregation along depth which, although consistent with data from studies of limnetic waters, cannot be related to populations of zooplankton in shallow littoral areas.     

The Freshwater Zooplankton of Sri Lanka,with a Discussion of Tropical Freshwater Zooplankton Composition

Based on the study of over 500 zooplankton samples collected in Sri Lanka (Ceylon) during 1965–1974, the species composition from different habitats is analysed. The zooplankton assemblage is typically tropical with relatively few species of Cladocera and Copepoda. The Rotifera include a large number of species of the genus Brachionus. The limnetic zooplankton resembles the pond zooplankton closely in that all the eurytopic species found in the different types of habitats, including ponds, also occur in the limnetic zooplankton. The large Cladocera belonging to the genus Daphnia are very rare. In general, large zooplankters are absent. The size composition of the zooplankton has a smaller range than in temperate regions. This is due to the absence of large-sized zooplankton species. The reasons for the differences in species variety and size composition between zooplankton of temperate and tropical regions is perhaps due to a number of factors. These include the effects of high and uniform temperatures, food availability and predation by fish and invertebrates.     

武汉东湖浮游动物数量和生物量变动的研究

本文报道了东湖Ⅰ、Ⅱ站1974—1975,1979—1980四个周年浮游动物种类组成和现存量的调查结果。束湖浮游动物的种类在减少,Ⅰ、Ⅱ站间种类组成的差别亦在缩小。浮游动物现存量的总趋势为逐渐增加。年数量变动曲线一般有夏季和秋季两个高峰,秋季高峰比夏季高峰更为突出。浮游动物总数的消长完全受原生动物数量的支配。年生物量的变动曲线不甚规则,不同的年份,Ⅰ、Ⅱ站均有所不同,以冬、春两季的生物量较高。四年年平均生物量统计结果:Ⅰ站原生动物占浮游动物总量的18.93%,轮虫占25.25%,枝角类占46.02%,桡足类占9.80%;Ⅱ站原生动物占总量的13.92%,轮虫占15.24%,枝角类占58.93%,桡足类占11.91%。本文还对影响浮游动物现存量变动的生态因子进行了讨论。       

Zooplankton in hollow-pools (using raised bogs in Vologda oblast, Russia, as an example)

Data on the biodiversity, structure, and seasonal dynamics of zooplankton communities in hollowpools of raised bogs in Vologda oblast are presented for the first time. The fauna of zooplankton communities in hollow-pools totals 38 species of plankton invertebrates (Rotatoria, 12; Cladocera, 19; and Copepoda, 7), and is mainly presented by acidophilic and sphagnophilic species. The water bodies are characterized by a high abundance and biomass of zooplankton organisms. The diversity and productivity of the zooplankton community increase with an increase in the area and depth of hollow-ponds. The seasonal dynamics of the abundance and biomass of zooplankton is similar in all groups of hollow-pools and depends on changes in the dominant complex of invertebrates.     

Distribution and Interannual Changes of the Zooplankton of the Durgun Water Basin and Adjoining Water Objects (the Western Mongolia)

The article describes quantitative and structural characteristics of zooplankton of polytypic sites of a water system including a lake, canal, and a water reservoir. It is shown that in the littoral zone of lakes and water reservoirs, the number of species and communities is higher, and biomass, lower. However, in the littoral zone of shallow lake zooplankton in number, took priority due to Rotifera, in the deep part of the water body – Rotifera and Cladocera; in the center of the lake zooplankton dominated by biomass due to Cladocera and Copepoda, in the water reservoir—due to the Copepoda. The dam area of the water reservoir had the highest species richness of zooplankton among all studied sites. The greatest number and biomass of zooplankton within a waterbody are noted in upper part, where a sedimentation zone had formed, and as a whole for the system of the investigated waterbodies, the maximum quantity indices are typical of lake communities. It is revealed that the starkest interannual changes in zooplankton were observed in the shallow lake: the number of species decreased—in the littoral zone at the expense of Rotifera, and in the center, the biomass increased at the expense of Cladocera; in deep-water area of the dam area of the reservoir, conversely, the number of species, as well as the number and biomass of the community, increased due to Copepoda.     

The Cladocera and Copepoda of the Alta water-course, Northern Norway

Cladocera and Copepoda fauna, from ten lakes in the Alta water-course,northern Norway, have been collected and investigated. A totalof 42 species (34 Cladocera and 8 Copepoda) were recorded. Thenumber of Cladoceran species is high when compared with thatregistered for other areas of similar latitude, and Cladoceranspecies abundance is also greater than that reported for otherregions of northern and central Scandinavia. In addition, themean number of planktonic species present at any given timein the lakes (4.9 Cladocera and 3.4 Copepoda) was comparativelyhigh. Eight species have never been recorded as existing farthernorth than the Alta water-course, Three other species have beenrecorded at higher latitudes in North America, but not in Eurasia.Several species, of which there are only a few published records,arc rare in northern Scandinavia, and nine species were notconsidered by Illies (1978), as existing in the region of thepresent study.     

A Seasonal Quantitative Study of the Littoral Cladocera and Copepoda in a Bog Pond and an Acid Marsh in Newfoundland

A quantitative study was made of the littoral microcrustaceans in a bog pond and an acid marsh located on the Avalon Peninsula, Newfoundland, from May, 1972 to May, 1973. A total of 17 species of Cladocera and 7 species of Copepoda were found in La Manche Marsh, while 21 species of Cladocera and 5 species of Copepoda were collected in Round Pond. The maximum standing stocks were similar in the two localities. The dominant forms in the summer and fall in La Manche Marsh were Cladocera: Acantholeberis curvirostris, Biapertura intermedia, Chydorus sphaericus, and Ilyocryptus spinifer. In the winter the copepod, Macrocyclops albidus, was dominant, while Cyclops varicans rubellus was the most abundant species in the spring. Round Pond also was dominated by Cladocera in the summer and fall; namely, Acroperus alonoides, Alona rustica, Alonella excisa, Chydorus sphaericus, and Sida crystallina. The copepods, Eucyclops agilis and Macrocyclops albidus, were dominant in the winter and early spring.     

Fatty acid composition of Cladocera and Copepoda from lakes of contrasting temperature

相似文献   

Population structure of some pond Microcrustacea

Summary The aestival species composition of microcrustacea of eight ponds in southwestern Kansas is described. Two benthic Ostracoda and three planktonic Copepoda and eight planktonic Cladocera were collected.On the whole, the Copepoda were more abundant than the Cladocera. Patterns of relative abundance varied from week to week and were more varied than the patterns described for the limnetic zone of lakes. There were two or three copepods in each pond. Except for one pond which had no Cladocera, there were two to five species of Cladocera per pond.There were fourteen significant affinities among the plankters. Two species showed no affinity. The relationships among four recurrent groups were established. Group I contained one cyclopoid, one calanoid and two cladocerans, a pattern not unlike the typical limnetic community.The population structure of each species that occurred in more that one pond was analyzed by analysis of variance. Significant differences between the ponds occurred from various species in per cent copepodids in the population, per cent females with eggs, and the number of eggs per egg sac. There was no significant difference among the ponds regarding the mean number of eggs per ovigerous female for any cladoceran.Interactions among the species and faunal characteristics of the ponds are discussed in relation to the environmental characteristics of the ponds.

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Zusammenfassung Die Zusammensetzung der estivalen Arten von Mikrocrustacean von acht Teichen im Südwesten von Kansas wird beschrieben. Zwei benthische Ostracoden, drei planktonische Copepoden und acht planktonische Cladoceren wurden gefunden.Die Copepoden waren im allgemeinen häufiger als die Cladoceren. Die Schemen der relativen Anzahl wechselten von Woche zu Woche und waren unterschiedlicher als die Schemen für die limnische Seezone. Zwei oder drei Copepoden, sowie zwei bis fünf Arten von Cladoceren kamen in jedem Teich vor, ausser in einem Teich, in dem keine Cladoceren gefunden wurden.Vierzehn wichtige Übereinstimmungen wurden unter den Planktonern gefunden. Zwei Arten zeigten keine Affinität. Der Zusammenhang zwischen vier wiederkehrenden Gruppen wurden nachgewiesen. Gruppe I enthielt einen Cyclopoiden, einen Calanoiden und zwei Cladoceren, ein für typisch limnische Gemeinschaften übliches Schema.Die Bevölkerungsstruktur jeder Art, die in mehr als einem Teich vorkam, wurde durch Streuungsanalyse untersucht. Es wurden signifikante Unterschiede im Prozentsatz der Copepoden: Bevölkerung, der Weibchen mit Eiern, der Anzahl Eier im Brutraum für die verschiedenen Arten zwischen den Teichen gefunden. Keine signifikanten Unterschiede wurden in der Anzahl Eier pro eitragendem Weibchen der Cladoceren zwischen den Teichen gefunden.Auch der Einfluss der Umweltfaktoren der Teiche auf die Arten und auf die Fauna des Teiches wurde untersucht.

     

鹤地水库浮游生物与富营养化特征分析*

于2000年丰水期和枯水期调查分析了鹤地水库的营养状态及浮游生物特征。结果表明:鹤地水库营养盐含量很高,综合营养状态指数评价为中一富营养化水平。浮游植物丰水期和枯水期的细胞密度分别为1950.5～3509.7×10⁴cells·L^-1和130.5～231.3×10⁴cells·L^-1,蓝藻中的微囊藻和席藻数量占细胞总数的83%以上。在丰水期和枯水期,浮游植物的群落结构均为蓝藻-绿藻-硅藻型,优势种为微囊藻和席藻。次优势种由丰水期蓝藻中的粘球藻,颤藻,绿藻中的衣藻,和硅藻中的颗粒直链藻等转变为枯水期的蓝藻门的水华束丝藻和硅藻门的颗粒直链藻等富营养化指示种。鹤地水库的浮游动物种类不多,但数量很高。丰水期的无节幼体和桡足幼体数量很多,但从优势种类来说,轮虫以曲腿龟甲轮虫,纵长异尾轮虫,剪形臂尾轮虫为主,枝角类的优势种为长额象鼻蚤;枯水期时无节幼体的数量最多,桡足幼体数量急剧下降,优势种类则转变为枝角类的长额象鼻蚤和桡足类的广布中剑水蚤。两个水期浮游动物的优势种类均是以耐污种和广布性种类为主。     

Phenotypic variation and vulnerability to predation in juvenile bluegill sunfish (<Emphasis Type="Italic">Lepomis macrochirus</Emphasis>)

Bluegill sunfish (Lepomis macrochirus) are known to diversify into two forms specialized for foraging on either limnetic or littoral prey. Because juvenile bluegills seek vegetative cover in the presence of largemouth bass (Micropterus salmoides) predators, natural selection should favor the littoral body design at size ranges most vulnerable to predation. Yet within bluegill populations, both limnetic and littoral forms occur where vegetation and predators are present. While adaptive for foraging in different environments, does habitat-linked phenotypic variation also influence predator evasiveness for juvenile bluegills? We evaluate this question by quantifying susceptibility to predation for two groups of morphologically distinct bluegills; a limnetic form characteristic of bluegills inhabiting open water areas (limnetic bluegill) and a littoral form characteristic of bluegills inhabiting dense vegetation (littoral bluegill). In a series of predation trials, we found that bluegill behaviors differed in open water habitat but not in simulated vegetation. In open water habitat, limnetic bluegills formed more dense shoaling aggregations, maintained a larger distance from the predator, and required longer amounts of time to capture than littoral bluegill. When provided with simulated vegetation, largemouth bass spent longer amounts of time pursuing littoral bluegill and captured significantly fewer littoral bluegills than limnetic fish. Hence, morphological and behavioral variation in bluegills was linked to differential susceptibility to predation in open water and vegetated environments. Combined with previous studies, these findings show that morphological and behavioral adaptations enhance both foraging performance and predator evasiveness in different lake habitats.     

The numbers, biomass and transport downstream of micro-crustaceans and Hydra from Cow Green Reservoir (Upper Teesdale)

Fluctuations in numbers and biomass of Copepoda, Cladocera and Hydra drifting out of the Cow Green reservoir via the outflow were investigated during the period August 1972-November 1973. Cladocera, chiefly Daphnia hyalina var. lacustris Sars and Copepoda, were most abundant between July and September, occurring at mean densities of 1278 and 215 m^?3 respectively. Hydra was most abundant between August and October at a mean density of 19 m^?3. Winter densities of all groups were low and 98% of the total annual output occurred between July and October. An estimated 150 kg (136 kg of Cladocera, 13kg of Copepoda and 1 kg of Hydra) dry weight was released from the reservoir during the year November 1972-October 1973. During periods of peak abundance about 1–2% of the total fauna drifting out of the reservoir was found 6·5 km below the dam. The effect of reservoir discharge and flow in tributaries of the Tees on this transport downstream is discussed. It is suggested that the micro-crustaceans and Hydra, even if not fed upon directly, will have considerable influence on the Tees benthos when they settle out and decompose to produce a nutrient-rich detritus.     

Species richness of pelagic Cladocera of large lakes in the eastern hemisphere

The composition of the pelagic cladoceran species assemblages in some large, well-studied, lakes of Europe, Asia and Africa is reviewed based on original and literature data. In general, pelagic cladocerans are taxonomically less well studied than some littoral groups. Only the limnetic members of the family Sididae and some Daphnia have recently been revised, whereas knowledge of species diversity of other Daphniidae (including moinas) and Bosminidae is missing. Future detailed taxonomic studies may lead to considerable changes in understanding of limnetic zooplankton composition.     

Effect of temperature in laboratory studies on development and growth of Cladocera and Copepoda from Tjeukemeer, The Netherlands

SUMMARY. The effects of temperature on development and growth are described for the common Cladocera and Copepoda in Tjeukemeer. Eight cladoceran species and five copepod species have been investigated: Daphnia hyalina, Daphnia cucullata, Bosmina coregoni, Bosmina longirostris, Chydorus sphaericus, Ceriodaphnia pulchella, Diaphanosoma brachyurum, Leptodora kindtii, Acanthocyclops robustus, Mesocydops leuckarti, Diacyclops bicuspidatus, Cyclops vicinus vicinus and Eurytemora affinis . Growth is expressed as length increment per size class (cladocerans) or instar (copepods) per week and as the relationship between time and length. The curvilinear logarithmic equation: In D = In a + b (In T)² is fitted to the development times of eggs, combined naupliar instars and combined copepodite instars, as well as to the longevity of the adults. The results are compared with those found in the literature and differences are discussed.     

Island biogeography, diversity and dominance of zooplankton in crater lakes on the Azores

In July and August 1988 samples of zooplankton were collected from 17 lakes on four islands. Five species of Cladocera, three species of Copepoda and 30 species of Rotifera were found. The maximum numbers of species in any one lake were four planktonic Cladocera, two Copepoda and seven planktonic Rotifera (with up to six additional non-planktonic species). The smallest, most distant island had fewer species than the largest island nearest to the mainland, but the number of species in each lake was determined more by the size of the lake than by its location. This results in the most distant island having lakes containing the same number of species as lakes of similar size on islands nearer to the mainland. The numbers of zooplankton species in each of these lakes are significantly lower than the world average, and the dominance ratios are significantly higher.     

Evolutionary interplay between ecology,morphology and reproductive behavior in threespine stickleback,Gasterosteus aculeatus

Synopsis Throughout its range, freshwater populations in the Gasterosteus aculeatus species complex display remarkable differentiation of morphology and behavior, much of which reflects differences in ecological conditions among habitats. We first describe the ecological conditions that have led to morphological and behavioral divergence in two common lake types in British Columbia, Canada. Deep, oligotrophic lakes have favored the evolution of slender fish well adapted for feeding on plankton (limnetic, sensu McPhail 1984), whereas shallow, more eutrophic lakes with extensive littoral zones favor fish that are deeper-bodied and well adapted for feeding on benthic invertebrates. The latter forage in large groups that attack nests guarded by males and cannibalize the young within. Courtship in these lakes is relatively inconspicuous, a feature that apparently enhances nest survivorship. In limnetic populations, this form of cannibalism is usually absent and courtship is conspicuous. Because benthic populations tend to have larger bodies and hence, larger gapes than do limnetic fish we suggest that cannibalism may be facilitated by large body size or a correlated trait. We test this by comparing the morphology of populations exhibiting both group cannibalism and a second kind of cannibalism in which solitary females court males, gain access to nests as a consequence, and then cannibalize eggs without spawning. Our results suggest that differences in body size cannot explain variation among populations in cannibalistic tendencies but that body size may affect the effectiveness of cannibalism by females within populations.     

Colour plasticity and background matching in a threespine stickleback species pair

Examining differences in colour plasticity between closely‐related species in relation to the heterogeneity of background colours found in their respective habitats may offer important insight into how cryptic colour change evolves in natural populations. In the present study, we examined whether nonbreeding dorsal body coloration has diverged between sympatric species of stickleback along with changes in habitat‐specific background colours. The small, limnetic species primarily occupies the pelagic zone and the large, benthic species inhabits the littoral zone. We placed benthic and limnetic sticklebacks against extremes of habitat background colours and measured their degree of background matching and colour plasticity. Benthics matched the littoral background colour more closely than did the limnetics, although there was no difference between species in their resemblance to the pelagic background colour. Benthics were able to resemble both background colours by exhibiting greater directional colour plasticity in their dorsal body coloration than limnetics, which may be an adaptive response to the greater spectral heterogeneity of the littoral zone. The present study highlights how habitat‐specific spectral characteristics may shape cryptic coloration differences between stickleback species. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 902–914.     

The Chydorid Crustacean Alona diaphana (King), Limnetic in Lakes Awasa and Zwai,Ethiopia, with a Discussion of Littoral and Limnetic Zooplankton

Alona diaphana, a common littoral tropicopolitan cladoceran, occurs in the limnetic of two Ethiopian lakes in considerable numbers and over long periods of time. Our results are presented and the composition of limnetic and littoral zooplankton, in terms of previous records of such incursions, are discussed. The high persistent densities of A. diaphana are due to the extensive littoral areas in the lakes, where it originates, the high intrinsic rates of increase of this species, the low diversity of zooplankton, reducing competition and the low level of predation.