Publications

TitleAbstractYear
Filter
PMID
Filter
[pollution in lake leman. evidence for the accumulation of tin in crustacean plankton: first results obtained by x ray spectrography].zooplankton was collected monthly from leman lake, from november 1976 to april 1977. six of the most representative species of freshwater zooplankton were analyzed: bosmina sp, daphnia longispina, bythotrephes longimanus, leptodora kindtii, eudiaptomus gracilis and cyclops prealpinus. all of the samples were shown to accumulate tin in their different organs and tissues where high values were generally found. the consequences of concentration of this toxic element for aquatic food chains are disc ...1977409541
life-history traits of standard and autochthonous cladocerans: i. acute and chronic effects of acetylsalicylic acid.pharmaceuticals have been recognized as an important group of aquatic micropollutants, mainly because of their biologically active nature. acetylsalicylic acid (asa), which is the active compound of aspirin and many other pharmaceuticals, is consumed in large quantities every year. therefore, its acute and chronic effects on standard (daphnia magna) and autochthonous (daphnia longispina) daphnids were investigated. the results showed that asa impaired the survivorship, reproduction, and growth o ...200415352269
life-history traits of standard and autochthonous cladocerans: ii. acute and chronic effects of acetylsalicylic acid metabolites.metabolic products are often more toxic than their pharmacological parent compounds. therefore, the acute and chronic effects of the main metabolites--salicylic acid (sal), gentisic acid (gen), and o-hydroxyhippuric acid (hdp)--of acetylsalicylic acid (asa), the active ingredient in aspirin and many other pharmaceuticals, were assessed using standard (daphnia magna) and autochthonous (daphnia longispina) cladocerans. the sequence of decreasing levels of acute and chronic toxicity of asa metaboli ...200415352270
evaluation of water column and sediment toxicity from an abandoned uranium mine using a battery of bioassays.uranium mining activities in cunha baixa, mangualde (portugal), were extensive between 1967 and 1993, with high production of poor ore. ore exploitation left millions of tons of tailings in the surrounding area, close to human houses. contamination of the area (water and soil compartment) presently represents a serious hazard to humans and wildlife. the aim of this work was to evaluate the acute toxicity of water and sediments from a pond that floods a uranium mine pit, in two periods (spring an ...200717316767
coupling of the biochemical composition and calorific content of zooplankters with the microcystis aeruginosa proliferation in a highly eutrophic reservoir.the impact of the cyanobacteria microcystis aeruginosa on zooplankton dynamics was studied in the hypertrophic villerest reservoir (france). samples were collected and their biochemical composition and calorific content examined. three most abundant zooplankton species in the reservoir were considered: the cladoceran daphnia longispina and the copepods cyclops vicinus and eudiaptomus gracilis. the three species were differently affected by the microcystis aeruginosa blooms. daphnia longispina di ...200617203599
improved method for determining bacterial filtration rates in zooplankton.filtration rates were determined for a natural population of zooplankton grazers (bosmina longirostris [müll.], cyclops vicinus vicinus [ulianine], acanthodiaptomus denticornis [wierz.], and daphnia longispina [müll.]) by using h-labeled bacteria as food for these organisms. there was a relationship between filtration rates of the major zooplankton grazers and the prevailing algal and bacterial composition in the lake water. low filtration rates were obtained in the presence of colonial and fila ...198816347724
effects of acid mine drainage on the genetic diversity and structure of a natural population of daphnia longispina.the increase in resistance to contaminants can result in the loss of genetic diversity of impacted populations. in this work, the effects of acid mine drainage (amd) on the genetic diversity and structure of a historically exposed population of daphnia longispina were evaluated using amplified fragment length polymorphism (aflp) analysis. individual sensitivity to acute copper exposure was determined in order to characterize the populations in terms of metal tolerance and in an attempt to identi ...200919230987
a whole sample toxicity assessment to evaluate the sub-lethal toxicity of water and sediment elutriates from a lake exposed to diffuse pollution.the impact of diffuse pollution in aquatic systems is of great concern due to the difficult to measure and regulate it. as part of an ecological risk assessment (era), this study aims to use a whole sample toxicity assessment to evaluate the toxicity of water and sediment from lake vela, a lake that has been exposed to diffuse pollution. in this way, standard (algae: pseudokirchneriella subcapitata; cladoceran: daphnia magna) and local species (algae: aphanizomenon flos-aquae; cladoceran: daphni ...200918655178
Fine-scale genetic analysis of Daphnia host populations infected by two virulent parasites - strong fluctuations in clonal structure at small temporal and spatial scales.Numerous theoretical studies suggest that parasites impose a strong selection pressure on their host, driving genetic changes within host populations. Yet evidence of this process in the wild is scarce. In the present study we surveyed, using high resolution microsatellite markers, the genetic structure of cyclically parthenogenetic Daphnia hosts within two different Daphnia communities belonging to the Daphnia longispina hybrid complex. One community, consisting of a single host species, was in ...201222154851
assessing the toxicity on [c3mim][tf2n] to aquatic organisms of different trophic levels.ionic liquids (ils) are an exciting class of neoteric solvents that are being object of great attention as a potential replacement to conventional environmental damaging solvents in industrial applications. despite some progress concerning ils' toxicity and their environmental impact, the information about these compounds is still scarce. in this work, biological tests were performed to establish the toxicity of 1-methyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide, [c3mim][tf2n], in fi ...201020018392
chemical and biological recovery of lake saudlandsvatn, a formerly highly acidified lake in southernmost norway, in response to decreased acid deposition.we studied acid-sensitive organisms in lake saudlandsvatn in southernmost norway in relation to acidification: brown trout (salmo trutta), the caddisfly hydropsyche siltalai and the zooplankter daphnia longispina. the study lake was highly acidified with episodic ph depressions <5.0 in the 1970s and 1980s, and sulphur (s) deposition five times greater than the critical load. chemical recovery following reduced deposition of s became evident in the late 1990s, when the ph increased to 5.5-6.0. by ...201121669327
genetic diversity of two daphnia-infecting microsporidian parasites, based on sequence variation in the internal transcribed spacer region.microsporidia are spore-forming obligate intracellular parasites that include both emerging pathogens and economically important disease agents. however, little is known about the genetic diversity of microsporidia. here, we investigated patterns of geographic population structure, intraspecific genetic variation, and recombination in two microsporidian taxa that commonly infect cladocerans of the daphnia longispina complex in central europe. taken together, this information helps elucidate the ...201627206473
acute and chronic toxicity of betanal®expert and its active ingredients on nontarget aquatic organisms from different trophic levels.as a way to improve the efficacy to target organisms, new pesticide generation is based on technologically advanced coformulations of two or more active ingredients. one example is betanal®expert, a postemergence herbicide composed of an advanced micro droplet coformulation of phenmedipham, desmedipham, and ethofumesate. although its composed formulation brings an increase in the pesticide performance, it can also enhance its toxicity to nontarget species. therefore, the present study intends to ...201121374783
cross-species infection trials reveal cryptic parasite varieties and a putative polymorphism shared among host species.a parasite's host range can have important consequences for ecological and evolutionary processes but can be difficult to infer. successful infection depends on the outcome of multiple steps and only some steps of the infection process may be critical in determining a parasites host range. to test this hypothesis, we investigated the host range of the bacterium pasteuria ramosa, a daphnia parasite, and determined the parasites success in different stages of the infection process. multiple genoty ...201424116675
temperature effects on parasite prevalence in a natural hybrid complex.both host susceptibility and parasite infectivity commonly have a genetic basis, and can therefore be shaped by coevolution. however, these traits are often sensitive to environmental variation, resulting in genotype-by-environment interactions. we tested the influence of temperature on host-parasite genetic specificity in the daphnia longispina hybrid complex, exposed to the protozoan parasite caullerya mesnili. infection rates were higher at low temperature. furthermore, significant difference ...201120702454
filtering structures and particle size selection in coexisting cladocera.five commonly co-occurring cladocerans, holopedium gibberum, daphnia longispina, ceriodaphnia quadrangula, bosmina longispina, diaphanosoma brachyurum and the calanoid copepod eudiaptomus gracilis were fed monodisperse fluorescent latex beads (0.5, 1,5 μm) to reveal clearance rates and particle size selection. the results were compared to those obtained with labelled bacteria and yeast. all cladoceran species ingested the beads, and particle size selection varied from a strong predominance of th ...198528310864
multiple stressor differential tolerances: possible implications at the population level.the probability of the most sensitive genotypes being eliminated from a population due to a contaminant pulse--genetic erosion--is negatively associated to the within-genotype variation. a sensitive genotype with a small phenotypic variation would be more prone to be lost-a critically sensitive genotype. furthermore, natural populations inhabiting contaminated sites are usually exposed to several pollutants. such co- or sequential exposure can have severe effects if at least some tolerant clonal ...201626990542
[cladocera in bosten lake: community characteristics and driving factors].cladocera of 17 sampling locations in bosten lake were investigated 11 times from 2010 to 2013. their community structure and succession dynamics were elaborated, and their responses to environment factors were analyzed. the results showed that a total of 14 species were identified and 3 of them were the dominant species. compared with history data, species preferring oligotrophic conditions were decreasing or even disappeared, and species preferring eutrophic conditions had occupied the dominan ...201526915211
parental and hybrid daphnia from the d. longispina complex: long-term dynamics in genetic structure and significance of overwintering modes.in recent decades, hybridization has become a focus of attention because of its role in evolutionary processes. however, little is known about changes in genetic structure within and between parental species and hybrids over time. here, we studied processes of genetic change in parental species and hybrids from the daphnia longispina complex (crustacea, cladocera) over a period of six years across ten habitats. these cyclical parthenogens respond to fluctuating environments by switching from ase ...201626779592
local human pressures influence gene flow in a hybridizing daphnia species complex.anthropogenic environmental changes are considered critical drivers of the genetic structure of populations and communities through, for example, the facilitation of introgressive hybridization between syntopic species. however, the mechanisms by which environmental perturbations trigger changes in the genetic structure of populations and communities, such as the processes that determine the directionality of hybridization and patterns of mitochondrial introgression over many generations, remain ...201626717418
long-term patterns in the population dynamics of daphnia longispina, leptodora kindtii and cyanobacteria in a shallow reservoir: a self-organising map (som) approach.the recognition of long-term patterns in the seasonal dynamics of daphnia longispina, leptodora kindtii and cyanobacteria is dependent upon their interactions, the water temperature and the hydrological conditions, which were all investigated between 1999 and 2008 in the lowland sulejow reservoir. the biomass of cyanobacteria, densities of d. longispina and l. kindtii, concentration of chlorophyll a and water temperature were assessed weekly from april to october at three sampling stations along ...201526633032
[the role of chemoreception in forming of daphnia longispina sustainable population (the simulation experiments)].individual-based mathematical models may be considered a promising tool for studying the patterns of aquatic animals population development under conditions of exposure to various environmental factors including those ones that are difficult to measure directly. to test the hypotheses on the role of chemoreception in vital activity of aquatic invertebrates, we used the previously designed individual-based simulation model of a mass pelagic species, daphnia longispina, population. the model descr ...201526606791
how perceived predation risk shapes patterns of aging in water fleas.predation is an important selection pressure which shapes aging patterns in natural populations, and it is also a significant factor in the life history decisions of individuals. exposure to the perceived threat of size-dependent fish predation has been shown to trigger adaptive responses in animal life history including an increase in early reproductive output. in water fleas, this response to perceived predation risk appears to have a cost, as a lifespan in an environment free of predation cue ...201525985923
genetic structure of daphnia galeata populations in eastern china.this study presents the first examination of the genetic structure of daphnia longispina complex populations in eastern china. only one species, d. galeata, was present across the eight investigated lakes; as identified by taxon assignment using allelic variation at 15 microsatellite loci. three genetically differentiated d. galeata subgroups emerged independent of the type of statistical analysis applied. thus, bayesian clustering, discriminant analysis based on results from factorial correspon ...201525768727
a mixture of environmental organic contaminants in lake sediments affects hatching from daphnia resting eggs.despite the relevance of resting eggs for ecology and evolution of many aquatic organisms and their exposure to contaminants accumulating in sediments, ecotoxicological studies using resting eggs are vastly underrepresented. the authors established a method to perform exposure assays with resting eggs produced by the daphnia longispina species complex, key species in large lake ecosystems. a mixture of organic contaminants previously detected in sediments of lake greifensee was selected to test ...201525394187
response of daphnia's antioxidant system to spatial heterogeneity in cyanobacteria concentrations in a lowland reservoir.many species and clones of daphnia inhabit ecosystems with permanent algal blooms, and they can develop tolerance to cyanobacterial toxins. in the current study, we examined the spatial differences in the response of daphnia longispina to the toxic microcystis aeruginosa in a lowland eutrophic dam reservoir between june (before blooms) and september (during blooms). the reservoir showed a distinct spatial pattern in cyanobacteria abundance resulting from the wind direction: the station closest t ...201425380273
chronic aquatic effect assessment for the fungicide azoxystrobin.the present study examined the ecological effects of a range of chronic exposure concentrations of the fungicide azoxystrobin in freshwater experimental systems (1270-l outdoor microcosms). intended and environmentally relevant test concentrations of azoxystrobin were 0 µg active ingredient (a.i.)/l, 0.33 µg a.i./l, 1 µg a.i./l, 3.3 µg a.i./l, 10 µg a.i./l, and 33 µg a.i./l, kept at constant values. responses of freshwater populations and community parameters were studied. during the 42-d experi ...201425196149
hybridizing daphnia communities from ten neighbouring lakes: spatio-temporal dynamics, local processes, gene flow and invasiveness.in natural communities of cyclical parthenogens, rapid response to environmental change is enabled by switching between two reproduction modes. while long periods of asexual reproduction allow some clones to outcompete others, and may result in "clonal erosion", sexual reproduction restores genetic variation in such systems. moreover, sexual reproduction may result in the formation of interspecific hybrids. these hybrids can then reach high abundances, through asexual clonal reproduction. in the ...201424725969
the use of invertebrates as indicators of environmental change in alpine rivers and lakes.in alpine regions climatic change will alter the balance between water sources (rainfall, ice-melt, snowmelt, and groundwater) for aquatic systems, particularly modifying the relative contributions of meltwater, groundwater and rain to both rivers and lakes. while these changes are expected to have implications for alpine aquatic ecosystems, little is known about potential ecological tipping points and associated indicator taxa. we examined changes in biotic communities along a gradient of glaci ...201424650750
transport distance of invertebrate environmental dna in a natural river.environmental dna (edna) monitoring is a novel molecular technique to detect species in natural habitats. many edna studies in aquatic systems have focused on lake or ponds, and/or on large vertebrate species, but applications to invertebrates in river systems are emerging. a challenge in applying edna monitoring in flowing waters is that a species' dna can be transported downstream. whether and how far edna can be detected due to downstream transport remains largely unknown. in this study we te ...201424523940
local and regional founder effects in lake zooplankton persist after thousands of years despite high dispersal potential.we reconstructed the genetic structure of a planktonic crustacean daphnia longispina living in high mountain lakes and ponds in the pyrenees to investigate whether it was shaped by persistent founder effects originating shortly after the last glacial maximum or by ongoing dispersal and effective migration (gene flow). we found that the genetic structure can largely be explained by a single colonization event following gradual deglaciation of the pyrenees ~10 000-15 000 years ago. nuclear genetic ...201424393221
tolerance to copper and to salinity in daphnia longispina: implications within a climate change scenario.considering ippc climate change scenarios, it is pertinent to predict situations where coastal ecosystems already impacted with chemical contamination became exposed to an additional stressor under a future scenario of seawater intrusion. accordingly, the present study aimed at evaluating if a negative association between tolerance to a metal and to saltwater exists among genotypes of a freshwater organism. for this, five clonal lineages of the cladoceran daphnia longispina o.f. müller, exhibiti ...201323990877
discrete modeling of dynamics of zooplankton community at the different stages of an antropogeneous eutrophication.mathematical modeling is a convenient way for characterization of complex ecosystems. this approach was applied to study the dynamics of zooplankton in lake sevan (armenia) at different stages of anthropogenic eutrophication with the use of a novel method called discrete modeling of dynamical systems with feedback (dmds). simulation demonstrated that the application of this method helps in characterization of inter- and intra-component relationships in a natural ecosystem. this method describes ...201323934229
mercury toxicity to freshwater organisms: extrapolation using species sensitivity distribution.mercury toxicity to aquatic organisms was evaluated in different taxonomic groups showing the following species sensitivity gradient: daphnia magna > daphnia longispina > pseudokirchneriella subcapitata > chlorella vulgaris > lemna minor > chironomus riparius. toxicity values ranged from 3.49 μg/l (48 h-ec₅₀ of d. magna) to 1.58 mg/l (48 h-ec₅₀ of c. riparius). a species sensitivity distribution was used to estimate hazardous mercury concentration at 5 % level (hc5) and the predicted no effect c ...201323771310
modes and mechanisms of a daphnia invasion.whether exotic species invade new habitats successfully depends on (i) a change in the invaded habitat that makes it suitable for the invader and (ii) a genetic change in the invading taxon that enhances its fitness in the new habitat, or both. we dissect the causes of invasions of swiss lakes, north of the alps, by daphnia galeata (a zooplankter typical of eutrophic lakes, e.g. those south of the alps, which are also warmer) by comparing the fitness performance of eight geographically distribut ...201222513861
discrimination of hybrid classes using cross-species amplification of microsatellite loci: methodological challenges and solutions in daphnia.microsatellite markers are important tools in population, conservation and forensic studies and are frequently used for species delineation, the detection of hybridization and introgression. therefore, marker sets that amplify variable dna regions in two species are required; however, cross-species amplification is often difficult, as genotyping errors such as null alleles may occur. to estimate the level of potential misidentifications based on genotyping errors, we compared the occurrence of p ...201222487563
contaminant driven genetic erosion: a case study with daphnia longispina.natural populations exposed to pollutants are predicted to experience a loss of genetic diversity, especially through genetic drift, gene flow (emigration), and/or selection (as sensitive genotypes may be lost). in the present study, the authors discuss the use of selectable markers and neutral markers to evaluate a contaminant-driven loss of genetic diversity and possible implications of genetic erosion on populations' viability. viability could be reduced by altering life history parameters, e ...201222407826
natural distribution and co-infection patterns of microsporidia parasites in the daphnia longispina complex.microsporidia are intracellular parasites, frequently infecting the planktonic crustacean daphnia. questioning the ability to detect and identify microsporidia with conventional microscopic techniques, we applied molecular methods in order to investigate the distribution and co-infection patterns of this parasite among 8 communities of the daphnia longispina hybrid complex. eight microsporidian taxa were detected, including 3 that previously had not been characterized genetically. microsporidian ...201222405328
fine-scale temporal and spatial variation of taxon and clonal structure in the daphnia longispina hybrid complex in heterogeneous environments.cyclical parthenogenetic water fleas of the genus daphnia have become a prominent model organism in ecology and evolution. in the past, analyses of their population structure have been limited by the prevailing use of allozyme markers, which in general do not allow for the distinction of individual clones. in this study, we used 10 microsatellite markers to track changes in the taxonomic and clonal composition of daphnia populations, and traced the abundance of the most common clones in two euro ...201222280487
testing hypotheses on the resistance to metals by daphnia longispina: differential acclimation, endpoints association, and fitness costs.pollution by metals may lead to an increased tolerance in the exposed population through adaptive microevolution, with resistant genotypes becoming more abundant than in reference sites. this work investigated the outcomes associated with selection for resistance by testing three hypotheses to assess the following: do resistant versus sensitive clonal lineages of daphnia longispina differentially acclimate to metals during a long-term sublethal exposure, is there a significant correlation betwee ...201222278886
in situ aquatic bioassessment of pesticides applied on rice fields using a microalga and daphnids.this study assessed the effects of episodic contamination on a drainage canal adjacent to an area of intensive rice production (coimbra, portugal). four monitoring periods were considered [i) before herbicide application (day-14), ii) at the first application day (day 0), iii) 3 or 5 and iv) 6days after]. each one consisted in three complementary evaluation lines: a) physico-chemical analyses, b) whole effluent toxicity (wet) assays with pseudokirchneriella subcapitata, c) in situ bioassays to a ...201121669452
life-history consequences of adaptation to pollution. "daphnia longispina clones historically exposed to copper".the present study was conducted to assess life history effects of adaptation to pollution in daphnia longispina clones historically exposed to an acid mine drainage from an abandoned pyrite mine. four sensitive and resistant clones from reference and impacted populations were exposed to a range of copper exposure levels and their life history and physiological responses in terms of survival, reproduction, respiration and feeding rates compared. the most resistant clone was from 16 to 48 fold mor ...201121380530
ecotoxicological effects of mikado and viper on algae and daphnids.the toxicity of single and combined formulated herbicides (mikado and viper) was assessed on several endpoints in species from two trophic levels: algae growth-pseudokirchneriella subcapitata and chlorella vulgaris-immobilization and life-history traits (only for single compound toxicity) of daphnids-daphnia longispina and daphnia magna. viper was the most toxic formulated herbicide. it was hypothesized that the toxicity of both formulated herbicides could have been enhanced by adjuvants, especi ...201221374788
toxicity evaluation of natural samples from the vicinity of rice fields using two trophic levels.an ecotoxicological screening of environmental samples collected in the vicinity of rice fields followed a combination of physical and chemical measurements and chronic bioassays with two freshwater trophic levels (microalgae: pseudokirchneriella subcapitata and chlorella vulgaris; daphnids: daphnia longispina and daphnia magna). as so, water and sediment/soil elutriate samples were obtained from three sites: (1) in a canal reach crossing a protected wetland upstream, (2) in a canal reach surrou ...201121181262
genetic costs of tolerance to metals in daphnia longispina populations historically exposed to a copper mine drainage.the present study was conducted to assess three microevolutionary aspects of adaptation to pollution in daphnia longispina populations historically exposed to an acid mine drainage from an abandoned pyrite mine: pollution mediated effects in acute tolerance to copper (cu) and zinc (zn); pollution-mediated effects on genetic variability of tolerant and physiological traits related to fitness (feeding rates); and fitness costs of tolerance measured as genetic trade-offs between tolerance and feedi ...201020821524
clonal diversity, clonal persistence and rapid taxon replacement in natural populations of species and hybrids of the daphnia longispina complex.hybridization is common among cyclical parthenogens, especially in zooplankton species assemblages of the genus daphnia. to explore hybridization dynamics and the extent of clonal diversity in the daphnia longispina complex, we analysed population structure in eight permanent lakes. based on 15 microsatellite loci, three major taxonomic units emerged: two species, d. galeata and d. longispina and their f1 hybrids, supported by factorial correspondence analysis and two bayesian methods. at the sa ...201020819161
abundance-occupancy relationships in metapopulations: examples of rock pool daphnia.intraspecific positive relationships between abundance and occupancy are observed for many species, suggesting that the same processes drive local and regional species dynamics. two main groups of mechanisms explain this relationship: spatiotemporal variation in local population growth rates due to variation in habitat quality, or dispersal effects that increase occupancy of a species when locally abundant. several studies show that spatiotemporal variation in population growth rates causes posi ...201120740290
prey capture of pike esox lucius larvae in turbid water.pike esox lucius larvae captured fewer calanoid and cyclopoid copepods in turbid than in clear water, whereas no differences were detected in feeding rates on daphnia longispina. decreased capture of copepods may lead to lower growth and survival of e. lucius larvae in turbid areas, in particular, if cladocerans are scarce.201020557612
toxicity of two fungicides in daphnia: is it always temperature-dependent?the joint effect of increasing temperature and pollution on aquatic organisms is important to understand and predict, as a combination of stressors might be more noxious when compared to their individual effects. our goal was to determine the sensitivity of a model organism (daphnia spp.) to contaminants at increasing temperatures, allowing prior acclimation of the organisms to the different temperatures. prior to exposure, two daphnia genotypes (daphnia longispina species complex) were acclimat ...201627381036
reproductive and developmental toxicity of the herbicide betanal® expert and corresponding active ingredients to daphnia spp.the commercial herbicide formulation betanal® expert and its active ingredients (a.i.s) ethofumesate, phenmedipham and desmedipham were focused in this study. following questions yielding from a previous study, an in-depth analysis of the reproductive toxicity of the pesticide was made. long-term exposures of daphnia magna and daphnia longispina to betanal® expert, to each a.i. and to a customised mixture matching the a.i.s ratio within the commercial formulation were carried out, and deleteriou ...201627023815
could contaminant induced mutations lead to a genetic diversity overestimation?contaminant driven genetic erosion reported through the inspection of selectable traits can be underestimated using neutral markers. this divergence was previously reported in the aquatic system of an abandoned pyrite mine. the most sensitive genotypes of the microcrustacean cladoceran daphnia longispina were found to be lacking in the impacted reservoir near the entrance of the metal rich acid mine drainage (amd). since that divergence could be, at least partially, accounted for by mutagenicity ...201323686739
the role of food quality in clonal succession in daphnia: an experimental test.a high genetic variation and recurrent changes in the genetic structure have been found in many pelagic populations. however, evidence that directly links these changes to differences in the ecological performance of particular genotypes is scarce. we hypothesized that within daphnia, the specialization of clones occurring in a particular season to the food quality specific for that time of the year is responsible for the observed changes in the genetic structure of a population. this hypothesis ...201020499101
toxicity and organic content characterization of olive oil mill wastewater undergoing a sequential treatment with fungi and photo-fenton oxidation.olive oil mill wastewater (oomw) is responsible for serious environmental problems. in this study, the efficiency of two treatments involving fungi and photo-fenton oxidation, sequentially applied to oomw was analyzed for organic compounds degradation and toxicity mitigation. the treatment with fungi (especially pleurotus sajor caju) of diluted oomw samples promoted a reduction of their acute toxicity to daphnia longispina. although this fungi species have not induced significant color reduction ...200919740604
dynamic reticulate evolution in a daphnia multispecies complex.recent genomic data suggest that the role of hybridization in evolution might be more important than previously assumed. here, we examine species-specific differentiation and signatures of reticulation in a multi-species complex of the crustacean genus daphnia. we did a combined examination of mtdna, allozymes and its1 (a part of the nuclear ribosomal dna) in the daphnia longispina group. we focused on the sequence variation of its1 in two unambiguous species (d. galeata, d. cucullata) and two e ...200919484710
genetic erosion and population resilience in daphnia longispina o.f. müller under simulated predation and metal pressures.this study investigated the effects of nonselective predation (culling) and metal toxicity on the genetic diversity of laboratory populations of the cladoceran daphnia longispina. populations, comprising five clones differing in their sensitivity to lethal concentrations of a metal-rich mine drainage effluent, were subjected to all possible combinations of three levels (absent, weak, and strong) of each stressor. observed population densities were compared to those expected from a life history e ...200919379016
dynamics of abundance of experimental populations of daphnia longispina (o.f. müller, 1785) at stepwise changes in temperature. 201619341079
contribution of cyclic parthenogenesis and colonization history to population structure in daphnia.cyclic parthenogenesis, the alternation of parthenogenetic and sexual reproduction, can lead to a wide scope of population structures, ranging from almost monoclonal to genetically highly diverse populations. in addition, sexual reproduction in aquatic cyclic parthenogens is associated with the production of dormant stages, which both enhance potential gene flow among populations as well as impact local evolutionary rates through the formation of dormant egg banks. members of the cladoceran genu ...200919298264
[population dynamics of daphnia longispina (o.f. müller, 1785) and diaphanosoma brachyurum (lievin, 1848) (crustacea, cladocera) under stable and graded temperature regimes].laboratory experiments have been performed to study the effects of different temperature regimes-constant (16.3 +/- 0.8, 20.3 +/- 0.8, and 24.6 +/- 0.7 degrees c) and graded, with temperatures changing at intervals of 4.4 or 8.8 degrees c within the range of 15.1-25.4 degrees c--on the population dynamics of two dominant species of littoral zooplankton, daphnia longispina and diaphanosoma brachyurum. the results show that aperiodic stepwise changes in temperature within the ranges of 16.3-20.4, ...201619239116
daphnia hybridization along ecological gradients in pelagic environments: the potential for the presence of hybrid zones in plankton.the relative homogeneity of pelagic environments has been regarded as the reason for the absence of hybrid zones for hybridizing planktonic daphnia (crustacea: cladocera); occasional dominance of interspecific hybrids over parental species was explained by their temporal superiority in fluctuating environments. however, water bodies with spatially varying environmental conditions might facilitate the formation of hybrid zones in plankton. we studied the distribution of species and hybrids of the ...200818508758
effects of food availability on the acute and chronic toxicity of the insecticide methomyl to daphnia spp.the widespread increase of pesticides application in crops threats vicinal freshwater lentic ecosystems, frequently leading to their contamination. due to their position in the aquatic food web, the responses to these pesticide inputs of freshwater filter-feeding zooplankters, as daphnids, provide relevant information the general risk to the ecosystem of xenobiotics. moreover, cladoceran grazers often face fluctuations in food availability due to the phytoplankton dynamics in lentic water bodies ...200717727918
differential resistance to copper and mine drainage in daphnia longispina: relationship with allozyme genotypes.differential resistance to metal pollution in daphnia longispina populations was reported in previous studies. in this work, we tried to determine if variation in polymorphic enzymes, often referred as being under metal selection, were related with differences in resistance to acute single- and mixed-metal exposure. allozyme genotype of 20 putatively polymorphic enzymes, 48-h median lethal concentration (lc50) for copper, and median lethal time (lt50) for a 3% dilution of acid mine drainage (amd ...200717705644
[the usage of individual-oriented model in studies on the role of the maternal effect in the reproductive switch in cladocera].an individual-oriented model of the population of daphnia longispina, an abundant zooplankton species in lakes and temporary water bodies of the palaearctic temperate zone, is described. the concept of the model is based on the growth and reproduction potential of an individual and its ability to switch from parthenogenesis to gamogenesis, which is determined by the life conditions of three successive generations. the model was used for testing hypotheses on the role of maternal effect in the po ...200717691459
mature habitats associated with genetic divergence despite strong dispersal ability in an arthropod.populations may be bound by contemporary gene flow, selective sweeps, and extinction-recolonization processes. indeed, existing molecular estimates indicate that species with low levels of gene flow are rare. however, strong priority effects and local selective regimes may hinder gene flow (despite dispersal) sending populations on independent evolutionary trajectories. in this scenario (the monopolization hypothesis), population differentiation will increase with time and genealogical evidence ...200717407568
impact of 17alpha-ethinylestradiol on the plankton in freshwater microcosms--i: response of zooplankton and abiotic variables.we investigated effects of 17alpha-ethinylestradiol (ee) in vertebrate free 230 l still water microcosms. zooplankton composition and physico-chemical variables were observed during 4 weeks of pre-application, 6 weeks of dosing via controlled release, and a 12 weeks post-treatment period. in the treated microcosms, time-weighted averages of ee concentration ranged between 7 and 220 ng/l during the dosing period, with concentration maxima up to 724 ng/l. ee exposure resulted in a decrease of spec ...200817374547
short- and long-term responses of daphnia spp. to propanil exposures in distinct food supply scenarios.the widespread increase of pesticides application in crops frequently leads to the contamination of vicinal freshwater lentic ecosystems. herbicides such as propanil may impair cladoceran fitness, which is per se strongly influenced by the food availability and/or its acquisition efficiency. this work intended to evaluate the responses of daphnia magna and three clonal lineages belonging to the daphnia longispina complex to acute and chronic exposures of the herbicide propanil, as well as to ass ...200717150251
genetic adaptation to metal stress by natural populations of daphnia longispina.loss of genetic diversity in natural populations as a result of chemical contamination has been reported in some studies. here, four field populations of daphnia longispina, two from sites historically impacted by acid mine drainage (amd) and two from reference sites, were used to address four objectives: (1) identify differences in sensitivity between the stressed and reference populations; (2) distinguish between the components responsible for those differences (environmental influence vs gene ...200616677911
genetically determined resistance to lethal levels of copper by daphnia longispina: association with sublethal response and multiple/coresistance.the development of resistance to toxicants has been reported for a wide range of organisms. two questions were addressed in the present study: are genetically determined resistance responses at lethal levels (min to h) of copper associated with responses at extreme lethal (h to d) and sublethal levels and does genetically determined resistance to lethal levels of copper confer resistance to lethal levels of other chemicals? twelve cloned lineages of daphnia longispina, differing in their resista ...200516117117
lack of evidence for metallothionein role in tolerance to copper by natural populations of daphnia longispina. 200516094892
cytochrome b gene partial sequence and rapd analysis of two daphnia longispina lineages differing in their resistance to copper. 200516094891
avoidance of copper contamination by field populations of daphnia longispina.almost all terrestrial and aquatic assays that are accepted as standardized, or that have been proposed, involve the exposure of confined organisms to toxicants. if avoidance (sensu evasion, displacement) of contaminants occurs in real situations, then bioassays involving forced exposure severely underestimate pernicious effects of contamination. two main objectives were achieved in this study: to verify the occurrence of avoidance of copper by cladocerans; to determine the association between a ...200415230322
genetic determination of tolerance to lethal and sublethal copper concentrations in field populations of daphnia longispina.in order to study the effects of environmental pollution on the genetic diversity of natural populations, two field populations of the cladoceran daphnia longispina were sampled: one in a reference site (uncontaminated) and the other in a site historically stressed with acid mine drainage (amd). five hypotheses were formulated: (1) the stressed population presents a higher tolerance to lethal levels of copper than the reference population, (2) differences in tolerance to lethal levels, observed ...200415025163
[structural variations of the eye linked to daily vertical migrations of daphnia longispina].the role of the eyes, and more precisely that of the ommatidian pigments, in the control of daily rhythms of movement of daphnia longispina is investigated. in the laboratory, under permanent light (ll), the pigmentary modifications observed are globally similar to those observed in situ, except in their timing, around dusk, ll cycles do not coincide with the ascent of daphnids but precede it. this is the expression of an endogenous free-running rhythm. therefore, in d. longispina, an internal o ...200314746270
massive occurrence of heterotrophic filaments in acidified lakes: seasonal dynamics and composition.we documented permanent presence of heterotrophic filaments in three acidified lakes (ph<5) in the bohemian forest. due to acidification, crustacean zooplankton were absent in all but one lake. in terms of carbon flow, microorganisms were thus almost exclusive players in the pelagic food webs. variety of extremely long (>100 microm) heterotrophic filaments occurred in the lakes. the filaments usually accounted for >50% of total heterotrophic microbial biomass in the pelagic zone (medians of the ...200319719559
effect of food level on the acute and chronic responses of daphnids to lindane.the toxic effects of lindane on the zooplankton communities may be strongly related to the population fitness, which is highly dependent on food availability. in order to test this hypothesis, acute (immobilisation) and chronic (life-history) responses of daphnia longispina and daphnia magna, reared at different food levels (low, normal, and high), were assessed in laboratorial exposures to several concentrations of lindane. a bifactorial design was employed (food level versus lindane concentrat ...200414638297
effects of nonylphenol on zooplankton in aquatic microcosms.we investigated the effects of the endocrine disruptor nonylphenol (np) on the zooplankton assemblages of 230 l aquatic microcosms during a four-week preapplication period, a six-week np treatment via controlled release, and a six-week postapplication period. zooplankton assemblage change, investigated by ordination principal response curves (prc), was due to lower abundances of copepoda, rotifera, and cladocera. the most sensitive groups/taxa were copepoda larvae, followed by the rotifers synch ...200314587915
morphological defenses induced in situ by the invertebrate predator chaoborus: comparison of responses between daphnia pulex and d. rosea.the presence of plankton predators may induce altered morphology in their potential prey. to date, the mechanism of induction and adaptive value of such defensive responses have been examined in the laboratory. this study investigated the morphological defense structures induced by the invertebrate predator chaoborus in two coexisting daphnia species, d. pulex and d. rosea, in the field. in piscivore lake (gräfenhain, germany), continuous and intense biomanipulation had led to near elimination o ...200028308217
behaviour plasticity without learning: phenotypic and genetic variation of naïve daphnia in an ecological trade-off.the swimming behaviour of adult daphnia largely governs their depth, which has a direct effect on both individual foraging success and predation avoidance. we treated individual swimming behaviour as a threshold character and used directional changes in average clonal depth within experimental tubes as a test for character plasticity. we compared the swimming behaviours of two cohabiting, phenotypically similar daphnia (daphnia galeata and daphnia galeata-daphnia rosea hybrid) to determine (1) w ...200010860520
oxidative stress and defence mechanisms of the freshwater cladoceran daphnia longispina exposed to uv radiation.the aim of the present study is to evaluate the occurrence of oxidative stress in the cladoceran daphnia longispina exposed to uv-a and uv-b radiation. the activity of antioxidant enzymes and lipid peroxidation markers is investigated and the protective action of ascorbic acid determined. results show differences in the lethality radioinduced by uv-a and uv-b. both uv-a and uv-b exposure cause an important increase in malonaldehyde (mda) concentration and catalase activity. ascorbic acid additio ...200010836541
the microalgal food spectrum of daphnia longispina during the algal bloom of an eutrophic water body. 201610833653
phylogenetics and evolution of the daphnia longispina group (crustacea) based on 12s rdna sequence and allozyme variation.although members of the crustacean genus daphnia have been the target of much research, there is little understanding of the group's evolutionary history. we addressed this gap by inferring a phylogeny for one of the major species groups (longispina) using nucleotide sequence variation of a 525-bp segment of the mitochondrial 12s rdna and allozyme variation at 21 loci. we identified the major lineages and their relationships, assessed the phylogenetic utility of the few morphological characters ...19968744763
a pond mesocosm study to determine direct and indirect effects of lindane on a natural zooplankton community.we assessed the threshold concentrations for toxic effects by lindane on a zooplankton community using mesocosms in a natural pond. enclosures (1000 litres) were treated to give mean concentrations of 0, 2, 6, 12, 18, 24, and 50 microg litre(-1) over a test period of 39 days. larvae of the phantom midge chaoborus flavicans showed a high susceptibility to lindane and were virtually eliminated from enclosures with > or =12 microg litre(-1) 4 days after application. populations of cyclopoid nauplii ...199615091368
adaptation of inducible defense in euplotes daidaleos (ciliophora) to predation risks by various predators.the extent of induced morphological defense in euplotes daidaleos correlates to this ciliate's predation risk from the defense-inducing predator species. euplotes daidaleos responded by morphological transformation only to organisms that are able to feed on typically formed euplotes cells (63 ± 5 μm cell width in e. daidaleos). three of those potential predator species caused defensive changes to various degrees (student's t-test, p < 0.1 to p < 0.0001): lembadion bullinum (ciliata) induced 82 ± ...199524185414
habitat-dependent hybrid parentage and differential introgression between neighboringly sympatric daphnia species.allozyme, morphological, and pcr-generated mtdna markers were used to analyze hybrid parentage and introgression between the neighboringly sympatric crustaceans daphnia galeata mendotae and daphnia rosea. mtdna analysis of d. galeata mendotae from 15 lakes and of d. rosea from 8 lakes revealed species-specific fragment patterns resulting from taqi and rsai digestion. no individuals of one parent species possessed the typical mtdna of the other parent species, suggesting that mtdna introgression ...19938346220
chaoborus and fish-mediated influences on daphnia longispina population structure, dynamics and life history strategies.this study examined the long term effects of predation by larvae of the midge chaoborus and simulated fish predation on experimental daphnia longispina populations. chaoborus predation, relative to fish predation, led to populations composed of larger individuals as a whole, larger egg-bearing individuals, and a larger primiparous instar. daphnia retained helmets beyond the first instar in response to the presence of chaoborus. both types of predation, relative to predator-free controls, reduced ...199228313397
the effects of organic ligands on the survival of daphnia in zn solution.bioassays involving zinc alone and in combinations with two organic ligands, namely histidine and edta were conducted on daphnia longispina over a period of 96 h. the percentage of mortality was recorded and the median lethal concentration (lc50) at 96 h estimated. the 96 h lc50 of d. longispina in zinc solution was 91 micrograms/l whereas no values of lc50 were revealed when d. longispina were exposed to histidine or edta alone although the organic ligands seemed to exert harmful effects (e.g. ...19911781939
zooplankton community structure driven by vertebrate and invertebrate predators.a zooplankton community was established in outdoor experimental ponds, into which a vertebrate predator (topmouth gudgeon: pseudorasbora parva) and/or an invertebrate predator (phantom midge larva: chaoborus flavicans) were introduced and their predation effects on the zooplankton community structure were evaluated. in the ponds which had chaoborus but not fish, small- and medium-sized cladocerans and calanoid copepods were eliminated while rotifers became abundant. a large-sized cladoceran daph ...198928312636
discrimination by freshwater zooplankton between single algal cells differing in nutritional status.grazing rates of a freshwater copepod (diaptomus kenai) and a freshwater cladoceran (daphnia rosea) on the green alga selenastrum minutum were determined to be dependent on the nutritional status of individual cells. cells that were less nitrogen limited were ingested at a greater rate than cells reared under more nitrogen limited conditions. diaptomus displayed active discrimination, possibly via chemodetection, while daphnia expressed passive selection, probably via differential retention on f ...198928312583
epizooic ciliates (vorticella sp.) compete for food with their host daphnia longispina in a small polyhumic lake.clearance rates of epizooic ciliates (vorticella sp.) were measured together with their host, a planktonic cladoceran daphnia longispina by using fluorescent latex beads as tracers of food. vorticellans and their host graze on food of same size range (nanoplanktonic algae and bacteria). individual clearance rates of vorticella averaged 6.9 and 7.0 μl ind(-1) h(-1) and those of daphnia 463 and 708 μl ind(-1) h(-1) for beads with diameter 2.00 and 3.92 μm. on the average, epizooic vorticellans tog ...198728312288
regulation of rotifer densities by crustacean zooplankton in an oligotrophic montane lake in british columbia.to examine the relative demographic effects of predation and competition for food in rotifers during spring and summer in an oligotrophic lake, predator and competitor densities and food supplies were experimentally altered inside large enclosures. abundances of rotifer species were positively correlated with experimental densities of fourth instar chaoborus trivittatus larvae, a major crustacean predator in 1976. experimental alteration of the densities of daphnia rosea and diaptomus leptopus a ...198428309407
comparison of the influence of temperature on the egg development and growth of daphnia longispina o.f. müller (crustacea: cladocera) from two habitats in southern england.the growth and egg development times of daphnia longispina from two eutrophic habitats in southern england were studied using similar methods and fully acclimated animals. habitat differences in both these parameters are demonstrated and are discussed in relation to possible genetical dissimilarities between the populations. the sex ratio of offspring of animals from the two habitats also differed and this is discussed in terms of the populations' history. data on the growth of male animals are ...197528308822
[development of the method of culture of scenedesmus quadricauda i daphnia longispina labeled with radiophosphorus]. 201014383370
the effect of temperature on the intersex character of daphnia longispina. 194718921405
some effects of colchicine on heredity in daphnia longispina. 194017246972
the filtration apparatus of cladocera: filter mesh-sizes and their implications on food selectivity.the filtering apparatus of eleven cladoceran species was studied. the distances between the setulae, which act as filters, were measured. among adult individuals, they vary from 0.2 μm in diaphanosoma brachyurum to 4.7 μm in sida crystallina. species can be grouped according to the mesh-sizes, as "fine mesh filter-feeders": diaphanosoma brachyurum, ceriodaphnia quadrangula, chydorus sphaericus, daphnia cucullata and daphnia magna; "medium mesh filter-feeders": daphnia galeata, d. hyalina. d. pul ...198128309989
selective feeding of four zooplankton species on natural lake phytoplankton.grazing experiments evaluated by microscopical counting were conducted with different size classes of daphnia hyalina, d. galeata, eudiaptomus gracilis, and cyclops sp., all from lake constance, using natural lake phytoplankton as food. species-specific grazing selectivity coefficients were calculated for the dominant phytoplankton species from weekly experiments. specific selectivities were found to be largely invariant through the growing season. all zooplankters grazed more efficiently on phy ...198628311689
Displaying items 1 - 95 of 95