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Sample records for bdelloid rotifer adineta

  1. A subtelomeric non-LTR retrotransposon Hebe in the bdelloid rotifer Adineta vaga is subject to inactivation by deletions but not 5' truncations

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    Gladyshev Eugene A

    2010-04-01

    Full Text Available Abstract Background Rotifers of the class Bdelloidea are microscopic freshwater invertebrates best known for: their capacity for anhydrobiosis; the lack of males and meiosis; and for the ability to capture genes from other non-metazoan species. Although genetic exchange between these animals might take place by non-canonical means, the overall lack of meiosis and syngamy should greatly impair the ability of transposable elements (TEs to spread in bdelloid populations. Previous studies demonstrated that bdelloid chromosome ends, in contrast to gene-rich regions, harbour various kinds of TEs, including specialized telomere-associated retroelements, as well as DNA TEs and retrovirus-like retrotransposons which are prone to horizontal transmission. Vertically-transmitted retrotransposons have not previously been reported in bdelloids and their identification and studies of the patterns of their distribution and evolution could help in the understanding of the high degree of TE compartmentalization within bdelloid genomes. Results We identified and characterized a non-long terminal repeat (LTR retrotransposon residing primarily in subtelomeric regions of the genome in the bdelloid rotifer Adineta vaga. Contrary to the currently prevailing views on the mode of proliferation of non-LTR retrotransposons, which results in frequent formation of 5'-truncated ('dead-on-arrival' copies due to the premature disengagement of the element-encoded reverse transcriptase from its template, this non-LTR element, Hebe, is represented only by non-5'-truncated copies. Most of these copies, however, were subject to internal deletions associated with microhomologies, a hallmark of non-homologous end-joining events. Conclusions The non-LTR retrotransposon Hebe from the bdelloid rotifer A. vaga was found to undergo frequent microhomology-associated deletions, rather than 5'-terminal truncations characteristic of this class of retrotransposons, and to exhibit preference for

  2. Biochemical diversification through foreign gene expression in bdelloid rotifers.

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    Chiara Boschetti

    Full Text Available Bdelloid rotifers are microinvertebrates with unique characteristics: they have survived tens of millions of years without sexual reproduction; they withstand extreme desiccation by undergoing anhydrobiosis; and they tolerate very high levels of ionizing radiation. Recent evidence suggests that subtelomeric regions of the bdelloid genome contain sequences originating from other organisms by horizontal gene transfer (HGT, of which some are known to be transcribed. However, the extent to which foreign gene expression plays a role in bdelloid physiology is unknown. We address this in the first large scale analysis of the transcriptome of the bdelloid Adineta ricciae: cDNA libraries from hydrated and desiccated bdelloids were subjected to massively parallel sequencing and assembled transcripts compared against the UniProtKB database by blastx to identify their putative products. Of ~29,000 matched transcripts, ~10% were inferred from blastx matches to be horizontally acquired, mainly from eubacteria but also from fungi, protists, and algae. After allowing for possible sources of error, the rate of HGT is at least 8%-9%, a level significantly higher than other invertebrates. We verified their foreign nature by phylogenetic analysis and by demonstrating linkage of foreign genes with metazoan genes in the bdelloid genome. Approximately 80% of horizontally acquired genes expressed in bdelloids code for enzymes, and these represent 39% of enzymes in identified pathways. Many enzymes encoded by foreign genes enhance biochemistry in bdelloids compared to other metazoans, for example, by potentiating toxin degradation or generation of antioxidants and key metabolites. They also supplement, and occasionally potentially replace, existing metazoan functions. Bdelloid rotifers therefore express horizontally acquired genes on a scale unprecedented in animals, and foreign genes make a profound contribution to their metabolism. This represents a potential

  3. Phylogenomics of unusual histone H2A Variants in Bdelloid rotifers.

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    Karine Van Doninck

    2009-03-01

    Full Text Available Rotifers of Class Bdelloidea are remarkable in having evolved for millions of years, apparently without males and meiosis. In addition, they are unusually resistant to desiccation and ionizing radiation and are able to repair hundreds of radiation-induced DNA double-strand breaks per genome with little effect on viability or reproduction. Because specific histone H2A variants are involved in DSB repair and certain meiotic processes in other eukaryotes, we investigated the histone H2A genes and proteins of two bdelloid species. Genomic libraries were built and probed to identify histone H2A genes in Adineta vaga and Philodina roseola, species representing two different bdelloid families. The expressed H2A proteins were visualized on SDS-PAGE gels and identified by tandem mass spectrometry. We find that neither the core histone H2A, present in nearly all other eukaryotes, nor the H2AX variant, a ubiquitous component of the eukaryotic DSB repair machinery, are present in bdelloid rotifers. Instead, they are replaced by unusual histone H2A variants of higher mass. In contrast, a species of rotifer belonging to the facultatively sexual, desiccation- and radiation-intolerant sister class of bdelloid rotifers, the monogononts, contains a canonical core histone H2A and appears to lack the bdelloid H2A variant genes. Applying phylogenetic tools, we demonstrate that the bdelloid-specific H2A variants arose as distinct lineages from canonical H2A separate from those leading to the H2AX and H2AZ variants. The replacement of core H2A and H2AX in bdelloid rotifers by previously uncharacterized H2A variants with extended carboxy-terminal tails is further evidence for evolutionary diversity within this class of histone H2A genes and may represent adaptation to unusual features specific to bdelloid rotifers.

  4. Geography, climate, and patterns of genetic diversity in a bdelloid rotifer

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    Fontaneto, Diego; Tang, Cuong

    2013-01-01

    The interplay between climate (current and past) and geography is known to be associated with spatial biodiversity patterns. Here we analyse genetic diversity in a bdelloid rotifer species complex along a latitudinal transect in Europe from ~40?N, Sardinia, to ~80?N, Svalbard. Contrary to what is described for larger organisms, none of the analysed patterns of diversity correlates with climate, and a strange relationship with geographical distances is present.

  5. A functional difference between native and horizontally acquired genes in bdelloid rotifers.

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    Barbosa, Elton G G; Crisp, Alastair; Broadbent, Sarah E; Carrillo, Martina; Boschetti, Chiara; Tunnacliffe, Alan

    2016-09-15

    The form of RNA processing known as SL trans-splicing involves the transfer of a short conserved sequence, the spliced leader (SL), from a noncoding SL RNA to the 5' ends of mRNA molecules. SL trans-splicing occurs in several animal taxa, including bdelloid rotifers (Rotifera, Bdelloidea). One striking feature of these aquatic microinvertebrates is the large proportion of foreign genes, i.e. those acquired by horizontal gene transfer from other organisms, in their genomes. However, whether such foreign genes behave similarly to native genes has not been tested in bdelloids or any other animal. We therefore used a combination of experimental and computational methods to examine whether transcripts of foreign genes in bdelloids were SL trans-spliced, like their native counterparts. We found that many foreign transcripts contain SLs, use similar splice acceptor sequences to native genes, and are able to undergo alternative trans-splicing. However, a significantly lower proportion of foreign mRNAs contains SL sequences than native transcripts. This demonstrates a novel functional difference between foreign and native genes in bdelloids and suggests that SL trans-splicing is not essential for the expression of foreign genes, but is acquired during their domestication. PMID:27312952

  6. Spatial and temporal escape from fungal parasitism in natural communities of anciently asexual bdelloid rotifers.

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    Wilson, Christopher G; Sherman, Paul W

    2013-08-22

    Sexual reproduction is costly, but it is nearly ubiquitous among plants and animals, whereas obligately asexual taxa are rare and almost always short-lived. The Red Queen hypothesis proposes that sex overcomes its costs by enabling organisms to keep pace with coevolving parasites and pathogens. If so, the few cases of stable long-term asexuality ought to be found in groups whose coevolutionary interactions with parasites are unusually weak. In theory, antagonistic coevolution will be attenuated if hosts disperse among patches within a metapopulation separately from parasites and more rapidly. We examined whether these conditions are met in natural communities of bdelloid rotifers, one of the longest-lived asexual lineages. At any life stage, these microscopic invertebrates can tolerate the complete desiccation of their ephemeral freshwater habitats, surviving as dormant propagules that are readily carried by the wind. In our field experiments, desiccation and wind transport enabled bdelloids to disperse independently of multiple fungal parasites, in both time and space. Surveys of bdelloid communities in unmanipulated moss patches confirmed that fungal parasitism was negatively correlated with extended drought and increasing height (exposure to wind). Bdelloid ecology therefore matches a key condition of models in which asexuals persist through spatio-temporal decoupling from coevolving enemies.

  7. Bdelloid rotifer, Philodina species in the breeding containers of Aedes aegypti and Aedes albopictus.

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    Muniaraj, M; Arunachalam, N; Paramasivan, R; Mariappan, T; Philip Samuel, P; Rajamannar, V

    2012-12-01

    The vector mosquitoes of dengue and chikungunya fever, Aedes aegypti and Aedes albopictus have adapted to feed on humans and undergo larval and pupal development in natural and artificial freshwater collections. Although several studies reported, still, much information is required to understand the successful survival of Aedes mosquitoes in small temporary containers. In an investigation conducted in the chikungunya affected areas of Kerala state, India, the presence of Bdelloid rotifer, Philodina in 95% of breeding habitats of Ae. aegypti and Ae. albopictus was recorded. The role of Philodina in the breeding containers was investigated. It was found that while in control the number of Philodina was found increasing in the water sample during the study period of seven days, the number found decreased in the containers with larvae of Aedes. The gut content analysis also confirmed the presence of the rotating wheel, corona of Philodina in some of the specimen suggests its role as major larval food. PMID:23202612

  8. Spatiotemporal dynamics of soil rotifers in a South-Bohemian beech forest Dinâmica espaço-temporal de rotíferos edáficos em uma floresta de faias no sul da Boêmia

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    Miloslav Devetter

    2009-08-01

    Full Text Available The objective of this work was to determine seasonal variation and vertical distribution of the soil rotifer assemblage in a climax beech forest in South Bohemia. During 2005, soil rotifer was investigated to the species level. Soil samples of 10 cm² and 10 cm in depth were divided into five layers, which were processed separately. Thirty one rotifer species were identified during the investigation. Dominant species significantly changed throughout the seasons. The most abundant species were Encentrum arvicola and Wierzejskiella vagneri among the monogononts, and Adineta steineri, Ceratotrocha cornigera, Habrotrocha filum, Habrotrocha ligula, Macrotrachela plicata, Mniobia tentans, Mniobia incrassata and Mniobia granulosa among the bdelloids. Mean Shannon diversity index varied from 1.99 to 2.63. Total rotifer abundance varied from 212±63 to 513±127 10³ individuals m-2 along the year, with the highest numbers found in May, and the lowest in July. The great part of the community was concentrated in the upper (fresh litter and second (partially decomposed litter layers and significantly decreased in the soil vertical profile on all sampling dates. The highest rotifer density of 43 individuals g-1 was found in the upper layer in May.O objetivo deste trabalho foi determinar a variação sazonal e a distribuição vertical de comunidades de rotíferos edáficos em uma floresta de faias em clímax, no Sul da Boêmia. Durante 2005, as comunidades de rotíferos edáficos foram estudadas até o nível da espécie. Amostras de 10 cm² de área com 10 cm de profundidade foram divididas em cinco camadas, que foram processadas separadamente. Trinta e uma espécies de rotíferos foram identificadas durante a investigação. Todas as espécies dominantes tiveram variações significativas durante as estações climáticas. As espécies mais abundantes foram Encentrum arvicola e Wierzejskiella vagneri entre os monogonontes e Adineta steineri, Ceratotrocha

  9. Analysis of expressed sequence tags of the cyclically parthenogenetic rotifer Brachionus plicatilis.

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    Koushirou Suga

    Full Text Available BACKGROUND: Rotifers are among the most common non-arthropod animals and are the most experimentally tractable members of the basal assemblage of metazoan phyla known as Gnathifera. The monogonont rotifer Brachionus plicatilis is a developing model system for ecotoxicology, aquatic ecology, cryptic speciation, and the evolution of sex, and is an important food source for finfish aquaculture. However, basic knowledge of the genome and transcriptome of any rotifer species has been lacking. METHODOLOGY/PRINCIPAL FINDINGS: We generated and partially sequenced a cDNA library from B. plicatilis and constructed a database of over 2300 expressed sequence tags corresponding to more than 450 transcripts. About 20% of the transcripts had no significant similarity to database sequences by BLAST; most of these contained open reading frames of significant length but few had recognized Pfam motifs. Sixteen transcripts accounted for 25% of the ESTs; four of these had no significant similarity to BLAST or Pfam databases. Putative up- and downstream untranslated regions are relatively short and AT rich. In contrast to bdelloid rotifers, there was no evidence of a conserved trans-spliced leader sequence among the transcripts and most genes were single-copy. CONCLUSIONS/SIGNIFICANCE: Despite the small size of this EST project it revealed several important features of the rotifer transcriptome and of individual monogonont genes. Because there is little genomic data for Gnathifera, the transcripts we found with no known function may represent genes that are species-, class-, phylum- or even superphylum-specific; the fact that some are among the most highly expressed indicates their importance. The absence of trans-spliced leader exons in this monogonont species contrasts with their abundance in bdelloid rotifers and indicates that the presence of this phenomenon can vary at the subphylum level. Our EST database provides a relatively large quantity of transcript

  10. Rotifers ingest oocysts of Cryptosporidium parvum

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    Fayer, R.; Trout, J.M.; Walsh, E.; Cole, R.A.

    2000-01-01

    Six genera of rotifers including Philodina, Monostyla, Epiphanes, Euchlanis, Brachionus, and Asplanchna were exposed to oocysts of Cryptosporidium parvum cleaned of fecal debris. Unstained oocysts and those stained with fluorescein-conjugated monoclonal antibody were added to suspensions of viable rotifers and were examined by phase-contrast, differential interference contrast, and fluorescence microscopy. Rotifers of all six genera were observed ingesting oocysts. A maximum of 25 oocysts was observed in the stomachs of Euchlanis and Brachionus. Euchlanis and Epiphanes were observed excreting boluses containing up to eight oocysts. It was not determined whether rotifers digested or otherwise rendered oocysts nonviable.

  11. Factors affecting egg ratios in planktonic rotifers

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    Sarma, S.S.S.; Gulati, R.D.; Nandini, S.

    2005-01-01

    Edmondson’s egg ratio (number of amictic eggs per female) is an important life history variable, which has been in wide use to understand and predict patterns of population growth in planktonic rotifers under field conditions. It is also useful as an indicator of the health of rotifers under culture

  12. Ecotoxicology, ecophysiology, and mechanistic studies with rotifers.

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    Dahms, Hans-U; Hagiwara, Atsushi; Lee, Jae-Seong

    2011-01-17

    Invertebrates play an increasing role in assessing the impacts of environmental contaminants in aquatic ecosystems. Substantial efforts were made to identify suitable and environmentally relevant models for toxicity testing. Rotifers have a number of promising characteristics which make them candidates worth considering in such efforts. They are small, simple in their organization, genetically homozygous, easy to cultivate. Rotifers are further widely distributed and ecologically important in freshwaters, in estuaries and coast, and also play an important role in the transportation of aquatic pollutants across the food web. In the last decades there has been a substantial increase of contributions on rotifers, particularly in areas of their ecology, geophylogeny, genomics and their behavioral, physiological, biochemical and molecular responses, following exposure to environmental chemicals and other stressors. Gene expression analysis enables ecotoxicologists to study molecular mechanisms of toxicity. Rotifers also appear as useful tools in the risk assessment of pharmaceuticals and their metabolites that find their way into aquatic ecosystems because their sensitivity to some of these substances is higher than that of cladocerans and algae. In respect to endocrine disruptors, rotifers seem to be particularly sensitive to androgenic and anti-androgenic substances, whereas copepods and cladocerans are typically more affected by estrogens and juvenile hormone-like compounds. Generally, a combination of whole-animal bioassays and gene expression studies allow an understanding of toxicological mechanisms. The purpose of this review is to demarcate the potential of using rotifers as important invertebrate aquatic model organisms for ecophysiology, ecotoxicology and environmental genomics. This review does not claim to find reasons for a superior use of rotifers in these fields. But the different phylogenetic allocation of rotifers in the Platyzoa (formerly

  13. Planktonic rotifers from Lake Cerknica (Slovenia)

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    Schöll, K.

    2008-01-01

    The basic hydrobiological conditions as well as the planktonic Rotifer assemblages of the Lake Cerknica (Slovenia) were investigated first time in 2004-2005. 16 taxa were found, most of them are frequent in Central Europe. The preliminary results suggest a pressing need for further research.

  14. Effects of population outcrossing on rotifer fitness

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    Serra Manuel

    2010-10-01

    Full Text Available Abstract Background Outcrossing between populations can exert either positive or negative effects on offspring fitness. Cyclically parthenogenetic rotifers, like other continental zooplankters, show high genetic differentiation despite their high potential for passive dispersal. Within this context, the effects of outcrossing may be relevant in modulating gene flow between populations through selection for or against interpopulation hybrids. Nevertheless, these effects remain practically unexplored in rotifers. Here, the consequences of outcrossing on the rotifer Brachionus plicatilis were investigated. Cross-mating experiments were performed between a reference population and three alternative populations that differed in their genetic distance with regard to the former. Two offspring generations were obtained: F1 and BC ('backcross'. Fitness of the outcrossed offspring was compared with fitness of the offspring of the reference population for both generations and for three different between-population combinations. Four fitness components were measured throughout the rotifer life cycle: the diapausing egg-hatching proportion, clone viability (for the clones originating from diapausing eggs, initial net growth rate R for each viable clone, and the proportion of male-producing clones. Additionally, both the parental fertilisation proportion and a compound fitness measure, integrating the complete life cycle, were estimated. Results In the F1 generation, hybrid vigour was detected for the diapausing egg-hatching proportion, while R was lower in the outcrossed offspring than in the offspring of the reference population. Despite these contrasting results, hybrid vigour was globally observed for the compound measure of fitness. Moreover, there was evidence that this vigour could increase with the genetic differentiation of the outcrossed populations. In the BC generation, the hybrid vigour detected for the egg-hatching proportion in the F1

  15. Does haplodiploidy purge inbreeding depression in rotifer populations?

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    Ana M Tortajada

    Full Text Available BACKGROUND: Inbreeding depression is an important evolutionary factor, particularly when new habitats are colonized by few individuals. Then, inbreeding depression by drift could favour the establishment of later immigrants because their hybrid offspring would enjoy higher fitness. Rotifers are the only major zooplanktonic group where information on inbreeding depression is still critically scarce, despite the fact that in cyclical parthenogenetic rotifers males are haploid and could purge deleterious recessive alleles, thereby decreasing inbreeding depression. METHODOLOGY/PRINCIPAL FINDINGS: We studied the effects of inbreeding in two populations of the cyclical parthenogenetic rotifer Brachionus plicatilis. For each population, we compared both the parental fertilization proportion and F1 fitness components from intraclonal (selfed and interclonal (outcrossed crosses. The parental fertilization proportion was similar for both types of crosses, suggesting that there is no mechanism to avoid selfing. In the F1 generation of both populations, we found evidence of inbreeding depression for the fitness components associated with asexual reproduction; whereas inbreeding depression was only found for one of the two sexual reproduction fitness components measured. CONCLUSIONS/SIGNIFICANCE: Our results show that rotifers, like other major zooplanktonic groups, can be affected by inbreeding depression in different stages of their life cycle. These results suggest that haplodiploidy does not purge efficiently deleterious recessive alleles. The inbreeding depression detected here has important implications when a rotifer population is founded and intraclonal crossing is likely to occur. Thus, during the foundation of new populations inbreeding depression may provide opportunities for new immigrants, increasing gene flow between populations, and affecting genetic differentiation.

  16. Response to Signorovitch et al.

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    Flot, Jean-François; Debortoli, Nicolas; Hallet, Bernard; Van Doninck, Karine

    2016-08-22

    Signorovitch et al.[1] comment that an Oenothera-like meiosis [2] could produce a pattern similar to what we observed in our study of natural isolates of the bdelloid rotifer Adineta vaga, which we attributed to horizontal gene transfers (HGTs) [3]. Indeed, our HGT hypothesis appears at first sight difficult to conciliate with their observation of a congruent pattern of allele sharing at four large loci possibly located on different chromosomes [4]. However, one might imagine conditions under which massive horizontal gene transfer between bdelloid individuals could produce such a pattern, notably if the individuals involved had previously lost most of their heterozygosity because of their exposure to frequent desiccation (which produces DNA double-strand breaks [5]). In the published A. vaga genome the loss of heterozygosity due to large-scale gene conversion events or break-induced replication covers only about 10% of the genome [6], but this percentage may be much higher in environmental isolates that often experience dessication. Besides, if an Oenothera-like mode of meiosis occurs in bdelloids frequently enough to be detected in a single sampling of 29 individuals (as in [4]), one would expect males and meiosis to be observed at least occasionally, and instances of congruent allele sharing across loci should turn up frequently in genetic surveys. This was not the case in [3]: among the 82 A. vaga individuals sequenced for four nuclear markers, no trio of individuals presented congruent patterns of shared sequences at different loci. For these reasons, and in the absence of any direct evidence for an Oenothera-like meiosis in bdelloids, we still consider inter-bdelloid HGTs a more parsimonious explanation for our results. PMID:27554651

  17. Rotifer trophic state indices as ecosystem indicators in brackish coastal waters

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    Agnieszka Gutkowska

    2013-11-01

    Full Text Available Thanks to their short life cycles, rotifers react rapidly to changes in environmental conditions and so may be useful for biological monitoring. The objective of this paper was to investigate the applicability of rotifer trophic state indices as indicators of the trophic state of brackish waters, as exemplified by the Vistula Lagoon. Carried out in summer from 2007 to 2011, this study showed no significant correlation between the Lagoon's trophic state and the rotifer structure. This confirms the limited applicability of rotifer trophic state indices for evaluating water quality in brackish water bodies.

  18. Application of rotifer Brachionus plicatilis in detecting the toxicity of harmful algae

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    Yan, Tian; Wang, Yunfeng; Wang, Liping; Chen, Yang; Han, Gang; Zhou, Mingjiang

    2009-05-01

    The toxicity of seven major HAB (harmful algal bloom) species/strains, Prorocentrum donghaiense, Phaeocystis globosa, Prorocentrum micans, Alexandrium tamarense (AT-6, non-PSP producer), Alexandrium lusitanicum, Alexandrum tamarense (ATHK) and Heterosigma akashiwo were studied against rotifer Brachionus plicatilis under laboratory conditions. The results show that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6), or A. lusitanicum could maintain the individual survival and reproduction, as well as the population increase of the rotifer, but the individual reproduction would decrease when exposed to these five algae at higher densities for nine days; H. akashiwo could decrease the individual survival and reproduction, as well as population increase of the rotifer, which is similar to that of the starvation group, indicating that starvation might be its one lethal factor except for the algal toxins; A. tamarense (ATHK) has strong lethal effect on the rotifer with 48h LC50 at 800 cells/mL. The experiment on ingestion ability indicated by gut pigment change shows that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6) and A. lusitanicum can be taken by the rotifers as food, but A. tamarense (ATHK) or H. akashiwo can be ingested by the rotifers. The results indicate that all the indexes of individual survival and reproduction, population increase, gut pigment change of the rotifers are good and convenient to be used to reflect the toxicities of HAB species. Therefore, rotifer is suggested as one of the toxicity testing organisms in detecting the toxicity of harmful algae.

  19. Application of rotifer Brachionus plicatilis in detecting the toxicity of harmful algae

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    YAN Tian; WANG Yunfeng; WANG Liping; CHEN Yang; HAN Gang; ZHOU Mingjiang

    2009-01-01

    The toxicity of seven major HAB (harmful algal bloom) species/strains, Prorocentrum donghaiense, Phaeocystis globosa, Prorocentrum micans, Alexandrium tamarense (AT-6, non-PSP producer), Alexandrium lusitanicum, Alexandrum tamarense (ATHK) and Heterosigma akashiwo were studied against rotifer Brachionus plicatilis under laboratory conditions. The results show that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6), or A. lusitanicum could maintain the individual survival and reproduction, as well as the population increase of the rotifer, but the individual reproduction would decrease when exposed to these five algae at higher densities for nine days; H. akashiwo could decrease the individual survival and reproduction, as well as population increase of the rotifer, which is similar to that of the starvation group, indicating that starvation might be its one lethal factor except for the algal toxins; A. tamarense (ATHK) has strong lethal effect on the rotifer with 48h LC50 at 800 cells/mL. The experiment on ingestion ability indicated by gut pigment change shows that P.donghaiense, P. globosa, P. micans, A. tamarense (AT-6) and A. lusitanicum can be taken by the rotifers as food, but A. tamarense (ATHK) or H. akashiwo can be ingested by the rotifers. The results indicate that all the indexes of individual survival and reproduction, population increase, gut pigment change of the rotifers are good and convenient to be used to reflect the toxicities of HAB species. Therefore, rotifer is suggested as one of the toxicity testing organisms in detecting the toxicity of harmful algae.

  20. The toxicity of carbofuran to the freshwater rotifer, Philodina roseola.

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    Moreira, Raquel Aparecida; da Silva Mansano, Adrislaine; Rocha, Odete

    2015-04-01

    In this study, the effects of exposing the rotifer Philodina roseola to the pesticide carbofuran were investigated. Its range of sensitivity to potassium dichromate, the acute toxicity of active ingredient carbofuran and of carbofuran dosed as its commercial form, Furadan(®) 350 SC were determined. Chronic toxicity of carbofuran dosed as Furadan(®) 350 SC on P. roseola survival and fecundity were also studied. The sensitivity of P. roseola to K2Cr2O7 ranged from 29.52 to 64.67 mg L(-1), averaging 47.10 mg L(-1). The 48-h EC50 were 13.36 ± 2.63 mg L(-1) for carbofuran and 89.32 ± 6.52 mg L(-1) for commercial form. Chronic toxicity tests showed that the survival of this rotifer was not affected by the carbofuran dosed as Furadan(®) 350 SC at the concentrations tested and that at 1.56 and 3.12 mg L(-1) their fecundity was higher than in the absence of this commercial product, characterizing the hormesis phenomenon. The sensitivity profile of several species to carbofuran indicated that P. roseola is more susceptible to this pesticide than the fish Clarias batrachus, the bacterium Vibrio fischeri, the protozoan Paramecium caudatum and the rotifer Brachionus calyciflorus, although the acute toxicity of carbofuran dosed as Furadan(®) 350 SC to P. roseola is much lower than that of active ingredient carbofuran. The results also imply that the exacerbated use of pesticides and the constant, accelerated expansion of agricultural activity will make aquatic non-target species even more vulnerable. Furthermore, the relevant role of benthic organisms in aquatic environments justifies the inclusion of P. roseola and other benthic species in toxicity screening for risk assessment, regarding this environmental compartment.

  1. The toxicity of carbofuran to the freshwater rotifer, Philodina roseola.

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    Moreira, Raquel Aparecida; da Silva Mansano, Adrislaine; Rocha, Odete

    2015-04-01

    In this study, the effects of exposing the rotifer Philodina roseola to the pesticide carbofuran were investigated. Its range of sensitivity to potassium dichromate, the acute toxicity of active ingredient carbofuran and of carbofuran dosed as its commercial form, Furadan(®) 350 SC were determined. Chronic toxicity of carbofuran dosed as Furadan(®) 350 SC on P. roseola survival and fecundity were also studied. The sensitivity of P. roseola to K2Cr2O7 ranged from 29.52 to 64.67 mg L(-1), averaging 47.10 mg L(-1). The 48-h EC50 were 13.36 ± 2.63 mg L(-1) for carbofuran and 89.32 ± 6.52 mg L(-1) for commercial form. Chronic toxicity tests showed that the survival of this rotifer was not affected by the carbofuran dosed as Furadan(®) 350 SC at the concentrations tested and that at 1.56 and 3.12 mg L(-1) their fecundity was higher than in the absence of this commercial product, characterizing the hormesis phenomenon. The sensitivity profile of several species to carbofuran indicated that P. roseola is more susceptible to this pesticide than the fish Clarias batrachus, the bacterium Vibrio fischeri, the protozoan Paramecium caudatum and the rotifer Brachionus calyciflorus, although the acute toxicity of carbofuran dosed as Furadan(®) 350 SC to P. roseola is much lower than that of active ingredient carbofuran. The results also imply that the exacerbated use of pesticides and the constant, accelerated expansion of agricultural activity will make aquatic non-target species even more vulnerable. Furthermore, the relevant role of benthic organisms in aquatic environments justifies the inclusion of P. roseola and other benthic species in toxicity screening for risk assessment, regarding this environmental compartment. PMID:25588673

  2. Evidence of WSSV transmission from the rotifer (Brachionus plicatilis to the black tiger shrimp (Penaeus monodon postlarvae and means to control rotifer resting eggs using industrial disinfectants

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    Valeriano Corre, Jr

    2012-06-01

    Full Text Available Rotifers are considered possible vectors of the white spot syndrome virus (WSSV and have been implicated in its recurrence inpond-cultured shrimp. However, direct evidence of the transmission and the pathogenicity of this virus from rotifers to shrimp has been lacking.In the present study, the pathogenicity of WSSV transmitted from infected rotifers (Brachionus plicatilis to post larval black tiger shrimp(Penaeus monodon was investigated. Results show that WSSV transmitted from infected rotifers to post-larval P. monodon caused an 82%cumulative mortality as compared to a 9% mortality in the non-infected control group. We also investigated the possibility of industrial disinfectants(sodium hypochlorite, granulated calcium hypochlorite and formalin as possible means to inhibit the viability of rotifer resting eggs,considered a biological reservoir of WSSV in earthen ponds. Among the disinfectants that were tested, granulated calcium hypochlorite at 5mg/L was the most effective. The present study provides direct evidence of the high pathogenicity of WSSV transmitted from rotifers to postlarval P. monodon and shows the potential use of granulated calcium hypochlorite in pond disinfection. This treatment could be a promisingstrategy to inhibit the spread and recurrence of WSSV outbreaks in P. monodon culture.

  3. Morphological similarity and ecological overlap in two rotifer species.

    Directory of Open Access Journals (Sweden)

    Carmen Gabaldón

    Full Text Available Co-occurrence of cryptic species raises theoretically relevant questions regarding their coexistence and ecological similarity. Given their great morphological similitude and close phylogenetic relationship (i.e., niche retention, these species will have similar ecological requirements and are expected to have strong competitive interactions. This raises the problem of finding the mechanisms that may explain the coexistence of cryptic species and challenges the conventional view of coexistence based on niche differentiation. The cryptic species complex of the rotifer Brachionus plicatilis is an excellent model to study these questions and to test hypotheses regarding ecological differentiation. Rotifer species within this complex are filtering zooplankters commonly found inhabiting the same ponds across the Iberian Peninsula and exhibit an extremely similar morphology-some of them being even virtually identical. Here, we explore whether subtle differences in body size and morphology translate into ecological differentiation by comparing two extremely morphologically similar species belonging to this complex: B. plicatilis and B. manjavacas. We focus on three key ecological features related to body size: (1 functional response, expressed by clearance rates; (2 tolerance to starvation, measured by growth and reproduction; and (3 vulnerability to copepod predation, measured by the number of preyed upon neonates. No major differences between B. plicatilis and B. manjavacas were found in the response to these features. Our results demonstrate the existence of a substantial niche overlap, suggesting that the subtle size differences between these two cryptic species are not sufficient to explain their coexistence. This lack of evidence for ecological differentiation in the studied biotic niche features is in agreement with the phylogenetic limiting similarity hypothesis but requires a mechanistic explanation of the coexistence of these species not

  4. Cost of reproduction in selected species of zooplankton (rotifers and cladocerans)

    NARCIS (Netherlands)

    Sarma, S.S.S.; Nandini, S.; Gulati, R.D.

    2002-01-01

    Reproduction is an energetically costly biological process. Among the freshwater zooplankton, rotifers and cladocerans reproduce parthenogenetically and the cost of reproduction can be estimated using the life table data from demographic studies. Reduced probability of future survival or future repr

  5. Unexpected increases in rotifer resting egg abundances during the period of contamination of Lake Orta

    OpenAIRE

    Piscia, Roberta; Tabozzi, Simone; Roberta BETTINETTI; Liisa NEVALAINEN; Manca, Marina M.

    2016-01-01

    Despite their ecological importance and rapid response to environmental changes, rotifers are rarely included in palaeolimnological studies. Here, we describe changes in abundance (ABD) and morphotype (MTs) diversity of rotifer resting eggs in the sediments of deep subalpine Lake Orta, Italy, covering a period prior to (pre-) 1926, during long-term ammonia and metal pollution from a rayon factory, and subsequent recovery of water quality. Following the pollution and bacterial oxidation of the...

  6. Effect of UV- B radiation on the feeding behavior of the rotifer Brachionus plicatilis

    Institute of Scientific and Technical Information of China (English)

    FENG Lei; LI Xin; WANG Jinhe; HAN Honglei; TANG Xuexi; CHEN Xiguang

    2007-01-01

    Effect of UV - B radiation on the feeding behaviour of marine zooplankton is important to assessing the health harm of marine ecosystem due to the gradually enhanced UV - B radiation in air. However, there are a few studies on this topic. The feeding behavior of the rotifer, Brachionus plicatilis, under the treatment of UV - B radiation on five species of microalgae, i. e. , Chlorella sp. ,Tetraselmis chuii, Isochrysis galbana Park 8701, Chaetoceros muelleri Lermumerman, and Nitzschia clostertum, was studied. The results showed that the filtering and feeding rates of the rotifer decreased significantly with the dose increase of UV - B radiation when fed with five species of microalgae respectively (P < 0.05 ) which indicates UV - B radiation inhibits the feeding activities of the rotifer on microalage. The mixed culture experiments shows the rotifer preferred to feed Chlorella sp. , then C. muelleri, I.galbana, N. clostertum and T. chuii in turn if without UV - B radiation. Under the highest dose of UV - B radiation treatment (2.70 kJ/m2) , the rotifer preferred to feed C. muelleri, then Chlorella sp. , N. clostertum, I. galbana and T. chuii in turn.Chlorella sp. , I. galbana and C. muelleri became the more favorite foods of the rotifer while T. chuii and N. clostertum became less favorite foods. The change of feeding rate and feeding selectivity of zooplankton driven by the enhanced UV - B radiation will lead to the change in the structure of phytoplankton community.

  7. Feeding effect of selenium enriched rotifers on larval growth and development in red sea bream Pagrus major

    OpenAIRE

    Kim, Hee-Jin; Sakakura, Yoshitaka; Maruyama, Isao; Nakamura, Toshio; Takiyama, Kazushi; Fujiki, Haruyuki; Hagiwara, Atsushi

    2014-01-01

    Feeding trials were conducted to investigate the effect of selenium (Se)-enriched rotifers on growth and development of red sea bream Pagrus major larvae. Fish were reared from fertilized eggs (98% hatch rate) to 20. days post hatch (dph) at 19. °C with two different food sources; non-enriched S-type rotifers (0.0. μg. Se/g D.W., control diet) or Se-enriched rotifers (2.2. μg. Se/g D.W., Se-enriched diet) at 10. rotifers/mL, respectively. On the last day of larviculture, the Se-enriched diet ...

  8. Zooplankton competition promotes trade-offs affecting diapause in rotifers.

    Science.gov (United States)

    Aránguiz-Acuña, Adriana; Ramos-Jiliberto, Rodrigo; Serra, Manuel

    2015-01-01

    Facultative diapause should be favoured by natural selection in temporary variable habitats. Diapause patterns are evolutionary constrained because producing diapause is resource demanding, which might have implications for competitive dynamics and competitor coexistence through mechanisms such as the storage effect. Besides these implications, competition intensity might affect the quality of the diapausing stages and the reproductive success of the offspring emerging from them. We experimentally analysed traits involved in diapause in the cyclically parthenogenetic rotifer Brachionus calyciflorus, in relation to the presence of its competitor, the cladoceran Moina micrura. Under competition with Moina, Brachionus produced fewer diapausing eggs, most of which possessed visual attributes indicating a higher quality. These diapausing eggs produced under a competitive environment had a higher hatching success; however, the hatchlings exhibited a lower population growth rate. We propose the existence of trade-offs between traits related to diapause: the number of produced eggs, quality of these eggs and hatchling performance. Our results show that interspecific competition may cause fine-tuned changes in the life cycle patterns of the populations. Furthermore, these changes could affect that abundance and performance of competitors and thereby drive back effects on the competitive output. These diapause-driven feedback mechanisms may have strong implications for the dynamics of the natural communities. PMID:25464990

  9. The Complete and Updated "Rotifer Polyculture Method" for Rearing First Feeding Zebrafish.

    Science.gov (United States)

    Lawrence, Christian; Best, Jason; Cockington, Jason; Henry, Eric C; Hurley, Shane; James, Althea; Lapointe, Christopher; Maloney, Kara; Sanders, Erik

    2016-01-01

    The zebrafish (Danio rerio) is a model organism of increasing importance in many fields of science. One of the most demanding technical aspects of culture of this species in the laboratory is rearing first-feeding larvae to the juvenile stage with high rates of growth and survival. The central management challenge of this developmental period revolves around delivering highly nutritious feed items to the fish on a nearly continuous basis without compromising water quality. Because larval zebrafish are well-adapted to feed on small zooplankton in the water column, live prey items such as brachionid rotifers, Artemia, and Paramecium are widely recognized as the feeds of choice, at least until the fish reach the juvenile stage and are able to efficiently feed on processed diets. This protocol describes a method whereby newly hatched zebrafish larvae are cultured together with live saltwater rotifers (Brachionus plicatilis) in the same system. This polyculture approach provides fish with an "on-demand", nutrient-rich live food source without producing chemical waste at levels that would otherwise limit performance. Importantly, because the system harnesses both the natural high productivity of the rotifers and the behavioral preferences of the fish, the labor involved with maintenance is low. The following protocol details an updated, step-by-step procedure that incorporates rotifer production (scalable to any desired level) for use in a polyculture of zebrafish larvae and rotifers that promotes maximal performance during the first 5 days of exogenous feeding. PMID:26863035

  10. New scope on the relationship between rotifers and Biomphalaria alexandrina snails

    Institute of Scientific and Technical Information of China (English)

    Shereen Farouk Mossallam; Eglal Ibrahim Amer; Iman Fathy Abou-El-Naga

    2013-01-01

    Objective: To investigate the effect of rotifer internalization into snail tissue on the development of schistosomes. Methods:Susceptible laboratory-bred Biomphalaria alexandrina (B. alexandrina) snails were exposed to lab-maintained rotifers; Philodina spp., two weeks before and after being infected with Schistosoma mansoni (S. mansoni) miracidia. The consequent histopathological impact on snail tissues and cercarial biology were investigated before and after emergence from snails. Results:Contamination of B. alexandrina snails with philodina, two weeks before miracidial exposure, was found to hinder the preliminary development of S. mansoni cercariae inside the snail tissues. Furthermore, when snails were contaminated with rotifers two weeks post miracidial exposure; growth of already established cercariae was found to be retarded. The consequent influence of internalized rotifers within the snail tissue was clearly reflected on cercarial emergence, activity and infectivity along the four weeks duration of shedding. In the present study, comparison of snail histopathological findings and altered cercarial biology observed between the experimental and control groups indicated that the rotifers may have affected the levels of snail's energy reservoirs, which eventually was found to have had an adverse impact on reproduction, growth and survival of the parasite within the snail host, coupled with its performance outside the snail. Conclusions:In future biological control strategies of schistosomiasis, ritifers should be considered as a parasitic scourge of humanity.

  11. Population dynamics of planktonic rotifers in Lake Loosdrecht, the Netherlands, in relation to their potential food and predators

    NARCIS (Netherlands)

    Ooms-Wilms, A.L.; Postema, G.; Gulati, R.D.

    1999-01-01

    1. This study uses descriptive data to examine the shift in dominance in the rotifer community in summer from Keratella cochlearis to Anuraeopsis fissa in a shallow eutrophic lake. Population density and egg ratio were estimated from May to September for these small loricate rotifers, as well as the

  12. Bioconcentration and localization of lead in the freshwater rotifer Brachionus calyciflorus Pallas 1677 (Rotifera: Monogononta)

    International Nuclear Information System (INIS)

    We studied how lead is bioconcentrated and distributed in the rotifer Brachionus calyciflorus using metal histochemistry to locate lead granules, Leadmium Green® analysis to establish the route of uptake, atomic absorption to determined the bioconcentration factor (BCF), and detected the presence of microelements in the cuticle by X-ray microanalysis with scanning electron microscopy. Our results indicate: (a) the digestive system is the main route of lead uptake in the rotifer B. calyciflorus, (b) after 24-h lead is deposited in granules in the mastax and vitellarium, (c) our energy-dispersive X-ray microanalysis indicates decalcification taking place in the cuticle of the rotifer after a 24-h lead exposure, and (d) we determined a BCF = 115 for lead after a 24 h exposure. However, the route of mobilization and storage of intracellular lead are still not fully understood in B. calyciflorus.

  13. A Rotifer-Based Technique to Rear Zebrafish Larvae in Small Academic Settings.

    Science.gov (United States)

    Allen, Raymond L; Wallace, Robert L; Sisson, Barbara E

    2016-08-01

    Raising zebrafish from larvae to juveniles can be laborious, requiring frequent water exchanges and continuous culturing of live feed. This task becomes even more difficult for small institutions that do not have access to the necessary funding, equipment, or personnel to maintain large-scale systems usually employed in zebrafish husbandry. To open this opportunity to smaller institutions, a cost-efficient protocol was developed to culture Nannochloropsis to feed the halophilic, planktonic rotifer Brachionus plicatilis; the rotifers were then used to raise larval zebrafish to juveniles. By using these methods, small institutions can easily raise zebrafish embryos in a cost-efficient manner without the need to establish an extensive fish-raising facility. In addition, culturing rotifers provides a micrometazoan that serves as a model organism for teaching and undergraduate research studies for a variety of topics, including aging, toxicology, and predator-prey dynamics. PMID:26886557

  14. Bioconcentration and localization of lead in the freshwater rotifer Brachionus calyciflorus Pallas 1677 (Rotifera: Monogononta)

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado-Flores, Jesus, E-mail: jalvaflo@hotmail.com [Universidad Autonoma de Aguascalientes, Centro de Ciencias Basicas, Departamento de Quimica, Avenida Universidad 940, Aguascalientes, Ags., CP 20131 (Mexico); Rico-Martinez, Roberto, E-mail: rrico@correo.uaa.mx [Universidad Autonoma de Aguascalientes, Centro de Ciencias Basicas, Departamento de Quimica, Avenida Universidad 940, Aguascalientes, Ags., CP 20131 (Mexico); Ventura-Juarez, Javier, E-mail: jventur@correo.uaa.mx [Universidad Autonoma de Aguascalientes, Centro de Ciencias Basicas, Departamento de Morfologia, Avenida Universidad 940, Aguascalientes, Ags., CP 20131 (Mexico); Silva-Briano, Marcelo, E-mail: msilva@correo.uaa.mx [Universidad Autonoma de Aguascalientes, Centro de Ciencias Basicas, Departamento de Biologia, Avenida Universidad 940, Aguascalientes, Ags., CP 20131 (Mexico); Rubio-Franchini, Isidoro, E-mail: rubio_reyes@hotmail.com [Instituto de Servicios de Salud del Estado de Aguascalientes, Laboratorio Estatal de Salud Publica, Av. Siglo XXI 105, Ciudad Satelite Morelos, C.P. 20270, Aguascalientes, Ags. (Mexico)

    2012-03-15

    We studied how lead is bioconcentrated and distributed in the rotifer Brachionus calyciflorus using metal histochemistry to locate lead granules, Leadmium Green{sup Registered-Sign} analysis to establish the route of uptake, atomic absorption to determined the bioconcentration factor (BCF), and detected the presence of microelements in the cuticle by X-ray microanalysis with scanning electron microscopy. Our results indicate: (a) the digestive system is the main route of lead uptake in the rotifer B. calyciflorus, (b) after 24-h lead is deposited in granules in the mastax and vitellarium, (c) our energy-dispersive X-ray microanalysis indicates decalcification taking place in the cuticle of the rotifer after a 24-h lead exposure, and (d) we determined a BCF = 115 for lead after a 24 h exposure. However, the route of mobilization and storage of intracellular lead are still not fully understood in B. calyciflorus.

  15. Toxicity of triphenyltin chloride to the rotifer Brachionus koreanus across different levels of biological organization.

    Science.gov (United States)

    Yi, Andy Xianliang; Han, Jeonghoon; Lee, Jae-Seong; Leung, Kenneth M Y

    2016-01-01

    Although triphenyltin (TPT) compounds are ubiquitous pollutants in urbanised coastal environments in Asian regions, their toxicities to marine organisms are still poorly known. This study was designed to investigate the toxicity of triphenyltin chloride (TPTCl) on the rotifer Brachionus koreanus across different levels of biological organisation. Firstly, we concurrently performed a 24 h static-acute toxicity test and a 6-day semi-static multigenerational life-cycle test using the rotifer. Our results demonstrated that the 24-h median lethal concentration of TPTCl for the rotifer was 29.6 μg/L and the 6-day median effect concentration, based on the population growth inhibition, was 3.31 μg/L. Secondly, we examined the expression of 12 heat shock protein (hsp) genes, four glutathione S-transferase (GST) genes, one retinoid X receptor (RXR) gene and 13 cytochrome P450 (CYP) genes in the rotifers after exposure to 20 µg/L TPTCl for 24 h. Among these studied genes, hsp90α2, GST-O and CYP3045C1 were the most significantly up-regulated genes with a relative expression level up to 32.9, 4.4 and 62.6 folds, respectively. The expression of these three genes in the rotifers showed an increasing trend in the first few hours of TPTCl exposure, peaked at 3 h (hsp90α2 and GST-O) and 12 h (CYP3045C1) respectively, and then gradually returned to a lower level at 24 h. Such up-regulations of hsp and GST genes probably offer cellular protection against the TPT-mediated oxidative stress while the accelerated induction of CYP genes possibly facilitates the detoxification of this toxicant in the rotifer. PMID:25045140

  16. Unexpected increases in rotifer resting egg abundances during the period of contamination of Lake Orta

    Directory of Open Access Journals (Sweden)

    Roberta Piscia

    2016-04-01

    Full Text Available Despite their ecological importance and rapid response to environmental changes, rotifers are rarely included in palaeolimnological studies. Here, we describe changes in abundance (ABD and morphotype (MTs diversity of rotifer resting eggs in the sediments of deep subalpine Lake Orta, Italy, covering a period prior to (pre- 1926, during long-term ammonia and metal pollution from a rayon factory, and subsequent recovery of water quality. Following the pollution and bacterial oxidation of the ammonia, Lake Orta became the largest and deepest acid lake in Europe. Recovery of water quality followed both a ban on the discharge of industrial wastes, and a liming intervention in 1989 and 1990. We sectioned a sediment core collected from the deepest part of the lake (ORTA 07/2A to provide a high  time resolution, given the ca. 3-4 y cm-1 of sediment accumulation. Rotifer resting egg (RRE abundance and morphotypes were examined from the sediments and compared to limnological variables indicating the pollution. Rotifer resting egg abundance significantly increased with lake contamination (r=0.609 and -0.624 for copper and pH, respectively; P<0.001; n=27. A lake-water copper concentration threshold of ca. 40 µg L-1discriminated among pre-, during-, and post- pollution compositions of the rotifer morphotype assemblages. Diversity and morphotype richness increased during the recovery from copper pollution and with complete restoration from acidity, while abundance increased during pollution. The persistence of presumably viable Brachionus resting eggs and of hatched egg cases during the heavy pollution phase suggests that, unlike most other organisms, which were extirpated by the pollution of the lake, rotifers survived producing resting eggs, which secured future generations.

  17. Adverse effects and bioconcentration of chromium in two freshwater rotifer species.

    Science.gov (United States)

    Hernández-Ruiz, Esmeralda; Alvarado-Flores, Jesús; Rubio-Franchini, Isidoro; Ventura-Juárez, Javier; Rico-Martínez, Roberto

    2016-09-01

    Bioaccumulation of trivalent (CrIII) and hexavalent chromium (CrVI), and its adverse effects were studied in two rotifer species: Brachionus calyciflorus (two different strains), and Lecane quadridentata. Median Lethal Concentration (LC50) at 24 h of both species showed that CrVI is highly toxic: LC50 ranges from 4.7 × 10(-5) to 4 × 10(-6) mg L(-1)), compared with CrIII: LC50 ranges from 0.64 to 1.279 mg L(-1). Using the LC50 as an exposure concentration, and using atomic absorption, the bioconcentration factor (BCF) was obtained and BCFs of rotifers exposed to CrIII are four orders of magnitude lower than BCFs of rotifers exposed to CrVI. The effect of Cr on the elemental composition of the two species of rotifers in their structures by X-ray microanalysis by energy dispersion showed that Cr is found in intoxicated rotifers, but not in control rotifers. The basal immunoreactivity to metallothioneins is greater in B. calyciflorus than L. quadridentata. The immunoreactivity to metallothioneins decreases in B. calyciflorus when is exposed to CrIII, in contrast in L. quadridentata the immunoreactivity to metallothioneins increase when is exposed to CrIII, and the immunoreactivity to CrVI in L. quadridentata decrease. A mechanism is proposed in which the harder lorica of L. quadridentata acts as a barrier and accumulator of CrVI, and allows for attenuating responses like metallothionein production in L. quadridentata. Instead, in B. calyciflorus the lack of a harder lorica allows for deeper penetration of CrVI, and no time to produce attenuating measures. PMID:27258901

  18. New records of rotifers (Rotifera: Eurotatoria from Deepor Beel - a Ramsar site of India with an update on its rich rotifer diversity.

    Directory of Open Access Journals (Sweden)

    B.K. Sharma

    2015-03-01

    Full Text Available Plankton samples collected from Deepor Beel (a Ramsar site, during July 2011 to June 2013, revealed 155 species of Rotifera, belonging to 35 genera and 20 families.  Of these, 16 species belonging to eight genera and seven families are new records to the rotifer fauna of this wetland of northeast India.  Our observations raise the total richness of the phylum known till date from this important floodplain lake (beel of the Brahmaputra river basin to 171 species and thus highlight its biodiversity value as one of the globally rich Rotifera habitats.  The updated list is interesting for following meta-analyses of rotifer occurrence in this only well sampled freshwater ecosystem of the Indian sub-region. 

  19. USING ROTIFER POPULATION DEMOGRAPHIC PARAMETERS TO ASSESS IMPACTS OF THE DEGRADATION PRODUCTS FROM TRINITROTOLUENE PHYTOREMEDIATION

    Science.gov (United States)

    The objective of this study was to evaluate the aquatic chronic lethal and sublethal toxicity effects from the phytoremediation of water contaminated with 2,4,6-trinitrotoluene (2,4,6-TNT) by the wetland plant species Myriophyllum aquaticum (parrot feather). Rotifers (Brachionus...

  20. CONSUMPTIONS RATES OF SUMMER FLOUNDER LARVAE ON ROTIFER AND BRINE SHRIMP PREY DURING LARVAL REARING

    Science.gov (United States)

    Larval summer flounder Paralichthys dentatus were hatched and reared through metamorphosis in the laboratory. At several points in the rearing cycle, larvae were removed from their rearing chambers and placed in small bowls, where they were fed known quantities of the rotifer Bra...

  1. Ecological patterns of the rotifer communities in the Kaw River estuary (French Guiana)

    Science.gov (United States)

    Rougier, C.; Pourriot, R.; Lam-Hoai, T.; Guiral, D.

    2005-04-01

    A study of the rotifer fauna in the Kaw River estuary revealed significant quantitative and qualitative variations as a function of precipitation pattern and resulting hydrology and hydrochemistry. The rainy season (flood period) was characterized by the presence of about one hundred rotifer species of the periphytic continental type, each present at a very low average density (8 to 10 ind l -1). Rotifers generally constituted the majority of the zooplankton (above 70%). The dry season (low water period) was characterized by a small number (four) of species of the 'marine coastal' plankton type, showed the highest density peaks (>500 ind l -1). While the fluvial hydrodynamics during the rainy season contributed to a complete mixing of populations across the estuarine zone, the oceanic hydrodynamics during the dry season led to great population instability at the station level. At an annual scale, this estuarine zone is thus an essentially open environment that lacks a clearly-structured rotifer population, and which therefore most likely does not constitute a distinct, internally-functioning ecosystem.

  2. Use of flubendazole as a therapeutic agent against rotifers (Brachionus plicatilis) in intensive cultures of the harpacticoid copepod Tisbe holothuriae

    DEFF Research Database (Denmark)

    Steenfeldt, Svend Jørgen; Nielsen, Johan W.

    2010-01-01

    holothuria). Flubendazole was lethal to rotifers in concentrations as low as 0.05 mg L−1. There was no significant effect on the concentration of copepods, even at the highest concentration tested, i.e. 5.0 mg L−1 flubendazole. We conclude that flubendazole is an effective drug for control of B. plicatilis...... down production and subsequently use a therapeutic agent to eliminate all zooplankton in the system before restart with a stock culture free of rotifers. We tested flubendazole as a mean of controlling rotifers (Brachionus plicatilis) in intensive laboratory cultures of the harpacticoid copepod (Tisbe...

  3. Response of rotifer functional groups to changing trophic state and crustacean community

    Directory of Open Access Journals (Sweden)

    Marina MANCA

    2011-08-01

    Full Text Available Information based on taxon-based indices is species-specific while information gained from function-based research can give a comprehensive view of ecosystem processes. We applied the guild-ratio, an index based on the proportion of functional groups of rotifers (i.e. microphagous and raptorial species, on a long-term data set of Lago Maggiore. By applying seasonal trend decomposition based on smoothing techniques and non-metrical multidimensional scaling, we assessed the response of rotifer functional groups to changes in trophic state and climate. While the taxon-based indices showed smooth changes, the function-based index showed a dramatic shift from a raptorial to a microphagous dominance, with a back-shift to raptorial dominance starting in 2000. The seasonal peak of microphagous and raptorial dry weight was clearly separated in the pre-eutrophication period. When mesotrophic conditions prevailed both peaks overlapped, only to be separated again with re-oligotrophication. We attributed these alterations of rotifer functional groups to changes in competition with crustacean zooplankton and to decreased phytoplankton algal abundance and size while altered seasonality in functional groups could be related to inter-group competition for food. We hypothesise that the effects of trophic state (i.e. altered phytoplankton and climate (i.e. altered cladoceran community were transferred across trophic levels to rotifer functional groups. Our study highlights that functional groups are valid instruments for illustrating unifying principles in ecology through a better understanding of ecosystem processes and the interrelationship between trophic levels.

  4. Effects of diet on population development of the rotifer Brachionus plicatilis in culture

    Science.gov (United States)

    Planas, M.; Estévez, A.

    1989-06-01

    Experiments were conducted in order to observe the effect of five diets on the population development of the rotifer Brachionus plicatilis Müller under laboratory conditions. Diets were based on baker’s yeast ( Saccharomyces cerevisiae) and the algae Tetraselmis suecica and Isochrysis galbana, mixed, or as simple diets. Growth rates, fecundity and biometric parameters were studied for 15 days. The cultures were divided in a logarithmic phase and a harvesting phase. Rotifers fed on Tetraselmis, alone or mixed with yeast or Isochrysis, gave good performances with the best results in all the parameters studied. Average growth rates in all diets were similar during the exponential phase, with values ranging from 0.72 ( Tetraselmis and Tetraselmis + yeast) to 0.47 (yeast). During the harvesting phase there were high differences between diets, with rates highly reduced in the yeast-group (0.17) and good rates when Tetraselmis was ingested (0.65 0.51). This alga had a positive influence on the rotifers, increasing individual growth and fecundity.

  5. Diversity of Monogononta rotifer species among standing waterbodies in northern Cambodia

    Directory of Open Access Journals (Sweden)

    Ratha Sor

    2014-08-01

    Full Text Available The incidence and abundance of Monogononta rotifer species were recorded from lakes and reservoirs in the upper part of the Cambodian Mekong River basin in April and November 2010. One hundred and seven species are reported, 25 of which are new records to Cambodia and 8 taxa were unidentifiable to species level. Species richness at the regional and local scale was not significantly different between habitat types or between seasons, whether it was estimated using incidence or abundance data. Comparison of incidence data also revealed no significant difference from species richness of ponds concurrently sampled in the same region. There appeared to be a high level of diversity among sites that could not be attributed to nestedness or to the 5 environmental variables measured. Each habitat type and season offered substantially different rotifer communities, with the proportion of unshared species between sample sets ranging from 14-49%. Non-metric multidimensional scaling and PERMANOVA analyses also revealed clustering and significant differences among sample sets based on habitat type and season. Therefore, each habitat type and season contributed to the overall rotifer biodiversity. When the incidence data from this study are combined with those in previously reported studies, the overall species richness estimate for Cambodia is 403 species (95% CI = 386-432 and the number of species records has reached 306. 

  6. Efficacy of a commercial probiotic relative to oxytetracycline as Gram-negative bacterial control agents in a rotifer (Brachionus plicatilis) batch culture

    Science.gov (United States)

    Two trials were conducted to evaluate two gram-negative bacterial control strategies in batch cultures of the rotifer Brachionus plicatilis. In the first trial, rotifers at an initial density of 47/mL were cultured for 5 d and dosed with a 10-mg/L solution of either oxytetracycline or a commercial p...

  7. Feeding and filtration rates of zooplankton (rotifers and cladocerans) fed toxic cyanobacterium (Microcystis aeruginosa).

    Science.gov (United States)

    Pérez-Morales, Alfredo; Sarma, S S S; Nandini, S

    2014-11-01

    Microcystis aeruginosa is generally dominant in many Mexican freshwater ecosystems interacting with zooplankton species. Hence, feeding and filtration rates were quantified for three cladoceran (Daphnia pulex, Moina micrura and Ceriodaphnia dubia) and three rotifer species (Brachionus calyciflorus, Brachionus rubens and Plationus patulus) using sonicated M. aeruginosa alone or mixed with Scenedesmus acutus in different proportions (25, 50 and 75%, based on cell density), offering a combined initial density of 100,000 cells·ml(-1). All the three cladoceran species ingested M. aeruginosa (100-300 cells ind(-1) min(-1)) when fed exclusively with cyanobacterium. When green alga offered as exclusive diet, the number of cells ingested by the tested cladocerans varied from 80 to 400 cells ind(-1) min(-1). Compared to cladocerans, rotifers in general consumed much lower quantity (< 200 cells ind(-1) min(-1)) of M. aeruginosa and S. acutus. The filtration rate for Daphnia pulex was inversely related to the proportion of green alga in the diet. For other tested cladocerans, no such clear trend was evident. In mixed treatments containing M. aeruginosa, the filtration rate of Daphnia was highest (about 220 μl ind(-1) min(-1)) when the medium contained 75% of S. acutus. Among the rotifer species, P. patulus filtered highest volume (100 μl ind(-1) min(-1) from mixed diets containing higher proportions (50 or 75%) of M. aeruginosa. Thus, there were species-specific differences in the filtration and feeding rates of zooplankton when offered mixed diets of green algae and toxic cyanobacteria. These probably explain the coexistence of different zooplankton species in Microcystis-dominant waterbodies. PMID:25522500

  8. Filming of zooplankton: a case study of rotifer males and Daphnia magna

    Directory of Open Access Journals (Sweden)

    Pierluigi Colangeli

    2015-11-01

    Full Text Available Filming live organisms can give new insights into the hidden life of plankton. Accessibly priced digital cameras are now available for a large range of users. Here, we demonstrate the technical setup and workflow of using a single-lens reflex (DSLR camera to film the behaviour of males of two rotifer species, Brachionus angularis Gosse (1851 and Keratella cochlearis Gosse (1851, and of the cladoceran Daphnia magna Straus (1820. Rotifers are cyclical parthenogens that produce males only under certain environmental conditions. Thus, knowledge on rotifer males is still limited because of their ephemeral nature and because they are often smaller than females. We filmed males of B. angularis and K. cochlearis with a DSLR camera connected to a compound microscope to better understand their morphology and behaviour in comparison to conspecific females. While written descriptions have their scientific value, seeing is complementary because everyone can verify what has been described. We made our videos publicly accessible through links connected to the paper. Our videos are, to our best knowledge, the first on males of B. angularis and K. cochlearis. Furthermore, we filmed the behavioural response of D. magna to ultraviolet (UV radiation with a macro lens attached to the DSLR camera. Approaches like this are valuable tools in environmental teaching. To see live organisms with one’s own eyes may contribute to raising public awareness about the value of water resources and their hidden communities. In summary, filming can be a valuable tool to ignite scientific discussion, but the videos need an open-access platform where they can be referenced in a topic-related order.

  9. Biotic or abiotic factors: which has greater influence in determining the structure of rotifers in semi-arid reservoirs?

    Directory of Open Access Journals (Sweden)

    Daniele Jovem da Silva Azevêdo

    2015-03-01

    Full Text Available ObjectiveThe objective of this study is to evaluate whether the distribution of structural attributes of rotifers in reservoirs in the semiarid region is more strongly influenced by abiotic or biotic environmental factors (density of cyanobacteria.MethodSampling occurred in two reservoirs in the Paraíba Basin, northeastern Brazil (Poções and Camalaú during April and June 2012. Eight sampling points were distributed at two stations in each reservoir: the region near the entrance of the main tributary and region of the dam and collections were made in the limnetic and littoral zone in every season. To assess the abiotic influence and density of cyanobacteria in the distribution of the structural attributes of rotifers, environmental variables bivariate correlation was conducted in series.ResultsIn Poções reservoir, the distribution of rotifer biomass was negatively related to the density of cyanobacteria; among the environmental variables, chlorophyll-a and total nitrogen were negatively related to all of the tested structural attributes, while the concentrations of total phosphorus were strongly related to the abundance of rotifers. In the Camalaú reservoir, the biomass was a structural attribute with a stronger correlation to the density of cyanobacteria; between the environmental variables and Egeria densa, nitrate was negatively related to all of the attributes tested, while transparency was moderately related to the abundance, biomass and richness as well as Chara sp. with abundance.ConclusionsAssemblages of rotifers are more clearly related to environmental conditions, especially those indicative of trophic conditions, despite the density of cyanobacteria having been a factor that was positively related to the structural characteristics of rotifers and thus indicative of such structural assemblies. This can be used for analysis of local environmental condition factors.

  10. Variable selectivity and the role of nutritional quality in food selection by a planktonic rotifer

    International Nuclear Information System (INIS)

    To investigate the potential for selective feeding to enhance fitness, I test the hypothesis that an herbivorous zooplankter selects those food items that best support its reproduction. Under this hypothesis, growth and reproduction on selected food items should be higher than on less preferred items. The hypothesis is not supported. In situ selectivity by the rotifer Keratella taurocephala for Cryptomonas relative to Chlamydomonas goes through a seasonal cycle, in apparent response to fluctuating Cryptomonas populations. However, reproduction on a unialgal diet of Cryptomonas is consistently high and similar to that on Chlamydomonas. Oocystis, which also supports reproduction equivalent to that supported by Chlamydomonas, is sometimes rejected by K. taurocephala. In addition, K. taurocephala does not discriminate between Merismopedia and Chlamydomonas even though Merismopedia supports virtually no reproduction by the rotifer. Selection by K. taurocephala does not simply maximize the intake of food items that yield high reproduction. Selectivity is a complex, dynamic process, one function of which may be the exploitation of locally or seasonally abundant foods. (author)

  11. Morphology and ultrastructure of the freshwater rotifer Brachionus bidentatus (Monogononta: Brachionidae) using scanning and transmission electron microscopy.

    Science.gov (United States)

    Guerrero-Jiménez, Gerardo; Zavala-Padilla, Guadalupe; Silva-Briano, Marcelo; Rico-Martínez, Roberto

    2013-12-01

    The study of sexual reproductive behavior supported by ultrastructural evidence is important in rotifers to describe differences among potential cryptic species. In this research, the morphology of the rotifer Brachionus bidentatus is described at the ultrastructural level, using electronic microscopy, together with a brief description and discussion of its sexual reproductive behavior. The characteristics of the (a) male, (b) the female, (c) the sexual egg or cyst, (d) the partenogenic egg, (e) the no-fecundated sexual egg (male egg), and (f) the trophi, were described. Another part of this research is dedicated to the ultrastructure of the sex cells of the male rotifer B. bidentatus. Samples were obtained from La Punta pond in Cosio, Aguascalientes, Mexico (22 degrees 08' N - 102 degrees 24' W), and a culture was maintained in the laboratory. Fifty organisms, from different stages of the rotifer Brachionus bidentatus, were fixed in Formol at 4% and then prepared; besides, for the trophi, 25 female rotifer Brachionus bidentatus were prepared for observation in a JEOL 5900 LV scanning electronic microscope. In addition, for the observation of male sex cells, 500 males of Brachionus bidentatus were isolated, fixed and observed in a JEOL 1010 transmission microscope. Females of B. bidentatus in laboratory cultures had a lifespan of five days (mean+one SD = 4.69 +/- 0.48; N=13), and produced 4.5 +/- 3.67 (N=6) parthenogenetic eggs during such lifespan. In the case of non-fertilized sexual eggs, they produced up to 18 eggs (mean+one SD = 13 +/- 4.93; N=7). Sexual females produced a single cyst on average (mean +/- one SD = I +/- 0; N=20). For the sexual cycle, the time of copulation between male and female ranged from 10 to 40 seconds (mean +/- one SD = 17.33 +/- 10.55, N=7). The spermatozoa are composed of a celular body and a flagellum, the size of the body is of 300 nm while the flagellum measures 1 700nm. The rods have a double membrane. Their mean length is almost

  12. Rotifer community structure and assessment of water quality in Yangcheng Lake

    Institute of Scientific and Technical Information of China (English)

    CHEN Lijing; LIU Qiao; PENG Ziran; HU Zhongjun; XUE Junzeng; WANG Wu

    2012-01-01

    Rotifer community structure was investigated in Yangcheng Lake in 2008.Dominant species and species diversity indices were determined and QB/T was used to assess water quality.The annual average density and biomass of the rotifers in Yangcheng Lake was 2 894± 1 006 ind./L and 12.47± 10.28 mg/L,respectively.The highest densities were observed in the western portion of the lake in March,but the highest biomass occurred in inflowing creeks in September.Within a year of monitoring in Yangcheng Lake,93 species were identified and the dominant species were found to be Polyarthra trigla,Brachionus angularis,Keratella cochlearis,Keratella valga,Brachionus calyciflorus,and Filinia major.Of the species recorded,75 were pollution indicator species.Density and biomass exhibited significant positive correlations with water temperature (R=0.209,P=0.003; R=0.446,P=0.000),but the peak density showed two lags in response to chl a.According to the Jaccard similarity index (SJ),the greatest similarity among dominant species occurred between creeks and the eastern part of the lake.The annual average Shannon-Wiener diversity index H',Margalef richness index D and Pielou evenness index J were 1.96±0.34,1.61 ±0.50and 0.77±0.10,respectively.In all four areas of Yangcheng Lake,β- mesosaprobic species comprised the largest share of pollution indicator species.These data suggest that Yangcheng Lake is mesosaprobic.

  13. Impact of three phthalate esters on the sexual reproduction of the Monogonont rotifer, Brachionus calyciflorus.

    Science.gov (United States)

    Cruciani, V; Iovine, C; Thomé, J-P; Joaquim-Justo, C

    2016-01-01

    Phthalate esters are widespread contaminants that can cause endocrine disruption in vertebrates. Studies showed that molecules with hormonal activities in vertebrates and invertebrates can affect asexual and sexual reproduction in rotifers. We investigated the impact of di-hexylethyl phthalate (DEHP), di-butyl phthalate (DBP) and butylbenzyl phthalate (BBP), on the asexual and sexual reproduction of the freshwater monogonont rotifer Brachionus calyciflorus in order to determine a potential environmental risk for sexual reproduction. We observed that DEHP has no significant impact on both asexual and sexual reproduction up to 2 mg/L. DBP has a positive effect on asexual reproduction at concentrations from 0.05 to 1 mg/L, but depresses it at 2 mg/L. Sexual reproduction is only affected at 2 mg/L and the impact observed is negative. BBP displayed a negative impact on both asexual and sexual reproduction at 1 and 2 mg/L. However we showed that the impacts of BBP on mixis and fertilization rates observed are due to the decrease in population growth rates at these concentrations and not to a direct impact of BBP on the mixis and the fertilization processes. Our results show that sexual reproduction in B. calyciflorus is not more sensitive than asexual reproduction to any of the substances tested which indicates the mode of action of these molecules is related to general toxicity and not to an interference with potential endocrine regulation of sexual reproduction. Comparison of effect concentrations and surface water contamination by phthalate esters suggests these compounds do not constitute a risk for primary consumers in these environments. PMID:26666431

  14. Long-term competitive dynamics of two cryptic rotifer species: diapause and fluctuating conditions.

    Directory of Open Access Journals (Sweden)

    Carmen Gabaldón

    Full Text Available Life-history traits may have an important role in promoting species coexistence. However, the complexity of certain life cycles makes it difficult to draw conclusions about the conditions for coexistence or exclusion based on the study of short-term competitive dynamics. Brachionus plicatilis and B. manjavacasare two cryptic rotifer species co-occurring in many lakes on the Iberian Peninsula. They have a complex life cycle in which cyclical parthenogenesis occurs with diapausing stages being the result of sexual reproduction. B. plicatilis and B. manjavacasare identical in morphology and size, their biotic niches are broadly overlapping, and they have similar competitive abilities. However, the species differ in life-history traits involving sexual reproduction and diapause, and respond differently to salinity and temperature. As in the case of certain other species that are extremely similar in morphology, a fluctuating environment are considered to be important for their coexistence. We studied the long-term competitive dynamics of B. plicatilis and B. manjavacas under different salinity regimes (constant and fluctuating. Moreover, we focused on the dynamics of the diapausing egg bank to explore how the outcome of the entire life cycle of these rotifers can work to mediate stable coexistence. We demonstrated that these species do not coexist under constant-salinity environment, as the outcome of competition is affected by the level of salinity-at low salinity, B. plicatilis excluded B. manjavacas, and the opposite outcome occurred at high salinity. Competitive dynamics under fluctuating salinity showed that the dominance of one species over the other also tended to fluctuate. The duration of co-occurrence of these species was favoured by salinity fluctuation and perhaps by the existence of a diapausing egg bank. Stable coexistence was not found in our system, which suggests that other factors or other salinity fluctuation patterns might act as

  15. Biodiversity down by the flow: new records of monogonont rotifers for Italy found in the Po River

    Directory of Open Access Journals (Sweden)

    Giampaolo ROSSETTI

    2011-08-01

    Full Text Available Surveys on the zooplankton of the middle reach of the Po River (Northern Italy carried out from 2008 to 2010 led to the discovery of 24 species of monogonont rotifers that are new for Italy. Among the 17 recorded genera, six are new for the Italian fauna, while three species have never been reported in the Palaearctic Region before. Temporal patterns, abundance and site of occurrence of the species are provided. Available information on the ecology and distribution of each taxon was derived from the literature and is also reported. Most of the new records are littoral and/or benthic-periphytic taxa. Results of the present study underline the still unsatisfactory status of present biogeographical knowledge on monogonont rotifers and the need for detailed taxonomic surveys in order to improve our understanding of the ecology and distributional patterns of this group.

  16. Rotifer dynamics in three shallow lakes from the Salado river watershed (Argentina): the potential modulating role of incident solar radiation.

    Science.gov (United States)

    Diovisalvi, Nadia; Rennella, Armando M; Zagarese, Horacio E

    2015-11-01

    In turbid Pampean lakes, incident solar radiation is a major driver of plankton seasonal dynamics. Higher light availability in summer translates into higher primary production, and therefore more food for zooplankton grazers. However, experimental evidence suggests that food produced under the high irradiance conditions prevailing in summer are less suitable to sustain rotifer population growth than that produced under the lower irradiance conditions typical of winter. Here, we analysed time series datasets corresponding to three shallow lakes from the Salado river watershed. This analysis provided evidence for similar seasonal patterns of rotifer relative abundance over a large geographic area. In addition, we performed life table experiments to test the hypothesis that natural seston produced in winter could sustain higher population growth rates than seston produced in summer. We suggest that the natural seasonal changes in temperature and food generate successive time windows, which may be capitalized by the different grazer species, resulting in predictable phenology of grazer populations. PMID:26416592

  17. Rotifer community structure along a stretch under the influence of dams in the Upper Paraná River floodplain

    Directory of Open Access Journals (Sweden)

    Tatiane Mantovano

    2015-07-01

    Full Text Available The construction of reservoirs imposes substantial impact on freshwater ecosystems and changes the ecological aspects of the lotic system downstream of dams. We hypothesized an increasing dissimilarity between communities in the sampling sites according to increasing distance from the Porto Primavera Dam. In addition, we expect that the rotifer community in the last sampling site will be influenced more by environmental variables related to trophic status. Samplings were conducted under the water surface of ten sites on the Paraná River in August 2013. Environmental variables were also determined. The highest number of taxa belonged to families Brachionidae, Lecanidae and Trichocercidae. The most abundant species was observed to Synchaeta oblonga, Keratella cochlearis, Brachionus calyciflorus. The species dissimilarity between sampling sites, tested using the Sorensen index, showed high dissimilarity between sampling sites. Redundancy analysis indicated a significant relationship between environmental variables (total phosphorus and ammonia and abundance of Brachionus calyciflorus and Keratella cochlearis, in the last sampling site. Our results suggest a greater dissimilarity between the rotifer communities according to increasing distance from the Porto Primavera Dam. In addition, a higher influence of the environmental variables related to trophic conditions was observed in the last sampling site, and influenced indirectly the occurrence and abundance of some rotifer species, due to increased availability of food resources, confirming the predicted hypothesis.

  18. Rotifer assemblages (Rotifera: Eurotatoria of the floodplain lakes of Majuli River Island, the Brahmaputra river basin, northeast India

    Directory of Open Access Journals (Sweden)

    Bhushan Kumar Sharma

    2014-12-01

    Full Text Available Our plankton and semi-plankton collections from twelve floodplain lakes (beels of Majuli River Island, Upper Assam reveal 124 rotifer species (32 genera and 17 families; these merit biodiversity value as ~52.0% and ~30.0% of species, ~68.0 and ~45.0% of  genera and ~74.0 and ~65.0% of the families of the Phylum known from northeast India (NEI and India, respectively. Two species are new to India with Trichocerca uncinata as new record to the Oriental region.  Eleven species are new to the study area and we provide an updated list (144 species for following meta-analyses of Majuli Rotifera. Biogeographically important elements include one Australasian, four Oriental, four Palaeotropical and one cosmo (sub tropical species while several species are of regional distribution interest. The rotifer fauna is predominantly tropical and Lecanidae > Lepadellidae collectively include ~53.0% species but it records paucity of Brachionus species. Individual beels record total richness of 60-100 (77 ± 12 species, monthly richness between 24 ± 7-34 ± 7 species and maximum up to 54 species/sample. The results are characterized by high community similarities (59.7-90.4% vide Sørensen’s index, more rotifer homogeneity amongst beels, lack of any pattern of temporal richness variations and much limited influence of abiotic parameters.

  19. The Rotifer fauna of Guatemala and Belize: survey and biogeographical affinities.

    Science.gov (United States)

    García-Morales, Alma Estrella; Elías-Gutiérrez, Manuel

    2007-06-01

    Rotifer samples were obtained from 29 localities in northern Guatemala and central-southern Belize during March 2000 and June 2001. A total of 119 species were identified. Ten selected taxa are illustrated and commented: Euchlanis semicarinata, Lepadella apsicora, L. cryphaea, Lecane curvicornis f. lofuana, L. whitfordi, Monommata maculata, Scaridium bostjani, Trichocerca elongata f. braziliensis, and Z. hollaerti. The species Lepadella rhomboidula is a first record for the American Continent. The species are 71% cosmopolitan, 6 % tropicopolitan, and 4.2 % restricted to the subtropics. The Guatemala species number range was Petén-Itza lake (53 taxa), and Raxruja pool (three). La Democracia pool (49 taxa), and the Blue Hole sink-hole (six species) were the extremes in Belize. In total, 68 of the recorded taxa are new for Guatemala and 91 for Belize. Additionally, 47 species are registered by the first time in Central America. A comparison between these two countries and Mexico revealed that the south part of the latter conform a cluster with them, emphasizing the transitional character of this region between the Nearctics and the Neotropics. Furthermore, Guatemala and Belize have differences in species assemblages, as a response to the nature of their particular environments and topographical accidents. PMID:19069767

  20. A novel endogenous indole protects rodent mitochondria and extends rotifer lifespan.

    Directory of Open Access Journals (Sweden)

    Burkhard Poeggeler

    Full Text Available Aging is a multi-factorial process, however, it is generally accepted that reactive oxygen species (ROS are significant contributors. Mitochondria are important players in the aging process because they produce most of the cellular ROS. Despite the strength of the free-radical hypothesis, the use of free radical scavengers to delay aging has generated mixed results in vertebrate models, and clinical evidence of efficacy is lacking. This is in part due to the production of pro-oxidant metabolites by many antioxidants while scavenging ROS, which counteract their potentially beneficial effects. As such, a more effective approach is to enhance mitochondrial metabolism by reducing electron leakage with attendant reduction of ROS generation. Here, we report on the actions of a novel endogenous indole derivative, indolepropionamide (IPAM, which is similar in structure to melatonin. Our results suggest that IPAM binds to the rate-limiting component of oxidative phosphorylation in complex I of the respiratory chain and acts as a stabilizer of energy metabolism, thereby reducing ROS production. IPAM reversed the age-dependent decline of mitochondrial energetic capacity and increased rotifer lifespan, and it may, in fact, constitute a novel endogenous anti-aging substance of physiological importance.

  1. Light-dependent transcriptional events during resting egg hatching of the rotifer Brachionus manjavacas.

    Science.gov (United States)

    Kim, Hee-Jin; Suga, Koushirou; Kim, Bo-Mi; Rhee, Jae-Sung; Lee, Jae-Seong; Hagiwara, Atsushi

    2015-04-01

    Rotifer resting eggs often have to endure harsh environmental conditions during the diapause phase. They are stimulated by light to hatch. In order to study the hatching mechanism, we observed resting eggs and measured their transcriptional expression under different light exposure periods (total darkness, and after 30 min, and 4h light). By using differential-display reverse transcription PCR (DDRT-PCR), we isolated 80 genes that displayed different expression patterns in response to the three light treatments: 20 genes were expressed in total darkness, 40 different genes were differentially expressed under 30 min light, and 20 further genes were expressed after 4h of light. The resting eggs showed no phenotypic differences in embryonic development during the 4h illumination period. In general, the expression patterns of the analyzed genes in resting eggs were differentially modulated by light exposure time. In total darkness, resting eggs mainly expressed genes encoding cell defense and homeostasis functions. In the 30 min illumination group, we found enriched expression of genes encoding fatty acid metabolism-related components, including Acyl-CoA dehydrogenase (ACAD). Genes encoding cellular and embryonic developmental functions were highly observed in the 30 min-illuminated group but were not observed in the 4h-illuminated group. Real-time RT-PCR revealed that several transcripts such as encoding V-type H(+)-translocating pyrophosphatase (V-PPase) and Meckelin had prolonged expression levels when exposed to light for 4h. In the 4h illuminated group, the RecQ protein-like 5 (RECQL5) gene was enriched. This RECQL5 gene may be expressed to protect the developing embryo from continuous light exposure. The data presented in this study indicate that DDRT-PCR-aided gene screening can be helpful to isolate candidate genes involved in the hatching process. PMID:25703093

  2. Relative importance of the trophic and direct pathways on PCB contamination in the rotifer species Brachionus calyciflorus (Pallas)

    OpenAIRE

    Joaquim-Justo, Célia; Gosselain, V; Descy, Jean-Pierre; Thomé, Jean-Pierre

    1995-01-01

    To determine the contribution of food ingestion (trophic pathway) to PCB contamination of zooplankton in the river Meuse (Belgium), we used 14 C-labelled algae (Dictyosphaerium ehrenbergianum) to measure ingestion and assimilation rates in the rotifer species Brachionus calyciflorus . When the concentration of algae in the culture medium varied from 20 103 to 200 103 algal cells ml -1 (0.12 to 1 .18 mg C 1 - '), the Brachionus calyciflorus ingestion rate varied from 0 .25 ± 0 .12 to 1 .52 ± 0...

  3. Experimental Study on the Interspecific Interactions Between the Two Bloom-Forming Algal Species and the Rotifer Brachionus plicatilis

    Institute of Scientific and Technical Information of China (English)

    XIE Zhihao; XIAO Hui; TANG Xuexi; CAI Hengjiang

    2009-01-01

    The interspecific interactions between the rotifer Brachionus plicatilis and two harmful algal blooms (HAB) species were investigated experimentally by single culture method. B. plicatilis population and the growth of the two algae were compared at different algal cell densities. The results demonstrated that the B. plicatilis obtained sufficient nutrition from Prorocentrum dong-haiense to support net population increase. With exposure to 2.5×104 cells mL-1 of P. donghaiense, the number of B. plicatilis in-creased faster than it did when exposed to other four algal densities (5, 10, 15 and 20×104 cellsmL-1), and the increase rate of B. plicatilis population (r) at this algal density was 0.104±0.015rd-1. Cell densities ofP. donghaiense decreased due to the grazing of B. plicatilis. In contrast, Heterosigma akashiwo had an adverse effect on B. plicatilis population and its growth was largely unaffected by rotifer grazing. In this case, B. plicatilis population decreased and H. akashiwo grew at a rate similar to that of the control.

  4. Responses of the rotifer Brachionus calyciflorus to two tropical toxic cyanobacteria (Cylindrospermopsis raciborskii and Microcystis aeruginosa) in pure and mixed diets with green algae

    NARCIS (Netherlands)

    Soares, M.C.S.; Lürling, M.F.L.L.W.; Huszar, V.M.

    2010-01-01

    Cyanobacteria are known for being inadequate as a food source for zooplankton, whether by their toxicity, large size, lack of essential compounds or due to feeding inhibitors. In eutrophic systems, however, higher abundance of rotifers is often observed with higher abundance of cyanobacteria, which

  5. Effect of temperature and viscosity on swimming velocity of the copepod Acartia tonsa, brine shrimp Artemia salina and rotifer Brachionus plicatilis

    DEFF Research Database (Denmark)

    Larsen, Poul Scheel; Madsen, C.V.; Riisgard, H.U.

    2008-01-01

    Beating cilia are important organelles for swimming in many zooplanktonic aquatic organisms, including many invertebrate larvae, rotifers and ciliates, but other planktonic organisms, such as copepods and brine shrimps, use muscle-powered swimming appendages. In recent studies we found that the t...

  6. STUDY ON MIXIS POTENTIAL OF ROTIFER RESTING EGGS (BRACHIONUS PLICATILIS) WITH DIFFERENT COLLECTION TIMES AND DIFFERENT PRESERVATION PERIODS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The present study investigated the possible changes in the mixis potential of rotifer resting eggs produced by a single stock of Brachionus plicatilis and collected and preserved annually from 1985-1998. Several clones derived from each batch of resting eggs were cultured under the same conditions for 21 days. The percentage of clones appearing resting eggs and the average yield of resting eggs produced from each clone were recorded and statistically analyzed to find the differences between the mixis potential of those resting egg batches. Results showed that different batches of resting eggs had different mictic levels among their descendent clones; but no regular relationship was found between the mixis potential of resting eggs and their collection times/preservation periods. Several internal and external factors that might affect the mixis potential of resting eggs were discussed.

  7. STUDY ON MIXIS POTENTIAL OF ROTIFER RESTING EGGS( BRACHIONUS PLICATILIS ) WITH DIFFERENT COLLECTION TIMES AND DIFFERENT PRESERVATION PERIODS

    Institute of Scientific and Technical Information of China (English)

    周利; 郑严; 相建海

    2001-01-01

    The present study investigated the possible changes in the mixis potential of rotifer resting eggs produced by a single stock of Brachionus plicatilis and collected and preserved annually from 1985 - 1998. Several clones derived from each batch of resting eggs were cultured under the same conditions for 21 days. The percentage of clones appearing resting eggs and the average yield of resting eggs produced from each clone were recorded and statistically analyzed to find the differences between the mixis potential of those resting egg batches. Results showed that different batches of resting eggs had different mictic levels among their descendent clones; but no regular relationship was found between the mixis potential of resting eggs and their collection times/preservation periods. Several internal and external factors that might affect the mixis potential of resting eggs were discussed.

  8. Impact of several harmful algal bloom (HAB) causing species, on life history characteristics of rotifer Brachionus plicatilis Müller

    Science.gov (United States)

    Lin, Jianing; Yan, Tian; Zhang, Qingchun; Zhou, Mingjiang

    2016-07-01

    In recent years, harmful algal blooms (HABs) have occurred frequently along the coast of China, and have been exhibiting succession from diatom- to dinoflagellate-dominated blooms. To examine the effects of different diatom and dinoflagellate HABs, the life history parameters of rotifers ( Brachionus plicatilis Müller) were measured after exposure to different concentrations of HAB species. The HAB species examined included a diatom ( Skeletonema costatum) and four dinoflagellates ( Prorocentrum donghaiense, Alexandrium catenella, Prorocentrum lima and Karlodinium veneficum). Compared with the control treatment (CT), the diatom S. costatum showed no adverse impacts on rotifers. Exposure to dinoflagellates at densities equivalent to those measured in the field resulted in a reduction in all the life history parameters measured. This included a reduction in: lifetime egg production (CT: 20.34 eggs/ind.) reduced to 10.11, 3.22, 4.17, 7.16 eggs/ind., life span (CT: 394.53 h) reduced to 261.11, 162.90, 203.67, 196 h, net reproductive rate (CT: 19.51/ind.) reduced to 3.01, 1.26, 3.53, 5.96/ind., finite rate of increase (CT: 1.47/d) reduced to 1.16, 1.03, 1.33, 1.38/d, and intrinsic rate of population increase (CT: 0.39/d) reduced to 0.15, 0.03, 0.28, 0.32/d, for the dinoflagellates P. donghaiense, A. catenella, P. lima and K. veneficum, respectively. The results showed that the diatom S. costatum had no detrimental consequences on the reproduction and growth of B. plicatilis, however, the four dinoflagellates tested did show adverse effects. This suggests that dinoflagellate HABs may suppress microzooplankton, resulting in an increase in algal numbers.

  9. Intracellular haemolytic agents of Heterocapsa circularisquama exhibit toxic effects on H. circularisquama cells themselves and suppress both cell-mediated haemolytic activity and toxicity to rotifers (Brachionus plicatilis).

    Science.gov (United States)

    Nishiguchi, Tomoki; Cho, Kichul; Yasutomi, Masumi; Ueno, Mikinori; Yamaguchi, Kenichi; Basti, Leila; Yamasaki, Yasuhiro; Takeshita, Satoshi; Kim, Daekyung; Oda, Tatsuya

    2016-10-01

    A harmful dinoflagellate, Heterocapsa circularisquama, is highly toxic to shellfish and the zooplankton rotifer Brachionus plicatilis. A previous study found that H. circularisquama has both light-dependent and -independent haemolytic agents, which might be responsible for its toxicity. Detailed analysis of the haemolytic activity of H. circularisquama suggested that light-independent haemolytic activity was mediated mainly through intact cells, whereas light-dependent haemolytic activity was mediated by intracellular agents which can be discharged from ruptured cells. Because H. circularisquama showed similar toxicity to rotifers regardless of the light conditions, and because ultrasonic ruptured H. circularisquama cells showed no significant toxicity to rotifers, it was suggested that live cell-mediated light-independent haemolytic activity is a major factor responsible for the observed toxicity to rotifers. Interestingly, the ultrasonic-ruptured cells of H. circularisquama suppressed their own lethal effect on the rotifers. Analysis of samples of the cell contents (supernatant) and cell fragments (precipitate) prepared from the ruptured H. circularisquama cells indicated that the cell contents contain inhibitors for the light-independent cell-mediated haemolytic activity, toxins affecting H. circularisquama cells themselves, as well as light-dependent haemolytic agents. Ethanol extract prepared from H. circularisquama, which is supposed to contain a porphyrin derivative that displays photosensitising haemolytic activity, showed potent toxicity to Chattonella marina, Chattonella antiqua, and Karenia mikimotoi, as well as to H. circularisquama at the concentration range at which no significant toxicity to rotifers was observed. Analysis on a column of Sephadex LH-20 revealed that light-dependent haemolytic activity and inhibitory activity on cell-mediated light-independent haemolytic activity existed in two separate fractions (f-2 and f-3), suggesting that both

  10. Effect of high levels of the rotifer Lecane inermis on the ciliate community in laboratory-scale sequencing batch bioreactors (SBRs).

    Science.gov (United States)

    Fyda, Janusz; Babko, Roman; Fiałkowska, Edyta; Pajdak-Stós, Agnieszka; Kocerba-Soroka, Wioleta; Sobczyk, Mateusz; Sobczyk, Łukasz

    2015-10-01

    Due to its ability to feed on filamentous bacteria, the rotifer Lecane inermis has already been recognized as a potential control agent of activated sludge bulking, which is usually caused by the excessive growth of filamentous microorganisms. However, their effectiveness depends, in part, on their abundance. We studied the influence of high densities of L. inermis on the protozoan community in activated sludge from a wastewater treatment plant (WWTP) in 4 laboratory-scale sequencing batch bioreactors (SBRs). Two treatments and two controls were subjected to nutrient removal system in process similar to that used in a WWTP. The experiment lasted 9 days and was repeated in 24-h cycles, including phases of agitation with feeding, aeration and agitation and sedimentation with decantation at the end of the cycle. In total, 32 taxa were identified, among which 25 were ciliated protozoa, 4 were amoebae, 2 were flagellates, and one was a nematode. Rotifers were then introduced to 2 bioreactors at a final concentration of 500ind.mL(-1), and the taxonomic composition and abundance of the activated sludge microfauna were assessed 2, 5 and 8 days thereafter. The mean density of ciliates on the first day of experiment was 12,610ind.mL(-1) and diminished to 4868±432ind.mL-±432ind.mL(-1) in the control and 5496±638ind.mL(-1) in the rotifer-treated group on the last day. Thus, even extremely high densities of artificially introduced rotifers did not negatively affect the protozoan community. On the contrary, the protozoan community was more diverse in the treatment group than in the control.

  11. Mutualistic association of rotifer Philodina roseola with the branchiuran fish ectoparasite Argulus bengalensis at its embryonic stage.

    Science.gov (United States)

    Banerjee, Anirban; Poddar, Soumabrota; Manna, Subha; Saha, Samar Kumar

    2016-03-01

    Several rotifers including Philodina spp. are well known to make commensal and parasitic associations with different animals. The present investigation was carried out to decipher the relationship of Philodina roseola with a piscine ectoparasite Argulus bengalensis in its embryonic stage. Mechanical removal of the symbiont P. roseola from the argulid egg strips resulted in the complete (100%) failure in hatching. Several P. roseola individuals were found to feed on the solidified jelly coat of the eggs enabling the larvae to emerge under both laboratory and field conditions. Under the laboratory condition, the experimental removal of P. roseola did not affect the embryonic development, but it rendered the jelly coat intact; therefore, the larvae were unable to make hatching furrow and subsequently died. The results of our experiments thus prove this service-resource relationship to be a mutualism. Although the association is facultative for P. roseola, it is obligatory for Argulus spp. An act of intervention in this relationship thus offers a promising control of argulosis. PMID:27009886

  12. Sublethal gamma irradiation affects reproductive impairment and elevates antioxidant enzyme and DNA repair activities in the monogonont rotifer Brachionus koreanus

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jeonghoon; Won, Eun-Ji [Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Il-Chan; Yim, Joung Han [Division of Life Sciences, Korea Polar Research Institute, Incheon 406-840 (Korea, Republic of); Lee, Su-Jae [Department of Life Science, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Lee, Jae-Seong, E-mail: jslee2@skku.edu [Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2014-10-15

    Highlights: • No mortality within 96 h even at a high intensity (1200 Gy). • A reduced fecundity of Brachionus koreanus at over 150 Gy with a decrease in lifespan. • Dose-dependent ROS increase with GST enzyme activity at sub-lethal doses. • Significant impact on life table parameters, particularly fecundity. • Significant up-regulation of DNA repair-associated genes at sublethal doses. - Abstract: To examine the effects of gamma radiation on marine organisms, we irradiated several doses of gamma ray to the microzooplankton Brachionus koreanus, and measured in vivo and in vitro endpoints including the survival rate, lifespan, fecundity, population growth, gamma ray-induced oxidative stress, and modulated patterns of enzyme activities and gene expressions after DNA damage. After gamma radiation, no individuals showed any mortality within 96 h even at a high intensity (1200 Gy). However, a reduced fecundity (e.g. cumulated number of offspring) of B. koreanus at over 150 Gy was observed along with a slight decrease in lifespan. At 150 Gy and 200 Gy, the reduced fecundity of the rotifers led to a significant decrease in population growth, although in the second generation the population growth pattern was not affected even at 200 Gy when compared to the control group. At sub-lethal doses, reactive oxygen species (ROS) levels dose-dependently increased with GST enzyme activity. In addition, up-regulations of the antioxidant and chaperoning genes in response to gamma radiation were able to recover cellular damages, and life table parameters were significantly influenced, particularly with regard to fecundity. DNA repair-associated genes showed significantly up-regulated expression patterns in response to sublethal doses (150 and 200 Gy), as shown in the expression of the gamma-irradiated B. koreanus p53 gene, suggesting that these sublethal doses were not significantly fatal to B. koreanus but induced DNA damages leading to a decrease of the population size.

  13. Sublethal gamma irradiation affects reproductive impairment and elevates antioxidant enzyme and DNA repair activities in the monogonont rotifer Brachionus koreanus

    International Nuclear Information System (INIS)

    Highlights: • No mortality within 96 h even at a high intensity (1200 Gy). • A reduced fecundity of Brachionus koreanus at over 150 Gy with a decrease in lifespan. • Dose-dependent ROS increase with GST enzyme activity at sub-lethal doses. • Significant impact on life table parameters, particularly fecundity. • Significant up-regulation of DNA repair-associated genes at sublethal doses. - Abstract: To examine the effects of gamma radiation on marine organisms, we irradiated several doses of gamma ray to the microzooplankton Brachionus koreanus, and measured in vivo and in vitro endpoints including the survival rate, lifespan, fecundity, population growth, gamma ray-induced oxidative stress, and modulated patterns of enzyme activities and gene expressions after DNA damage. After gamma radiation, no individuals showed any mortality within 96 h even at a high intensity (1200 Gy). However, a reduced fecundity (e.g. cumulated number of offspring) of B. koreanus at over 150 Gy was observed along with a slight decrease in lifespan. At 150 Gy and 200 Gy, the reduced fecundity of the rotifers led to a significant decrease in population growth, although in the second generation the population growth pattern was not affected even at 200 Gy when compared to the control group. At sub-lethal doses, reactive oxygen species (ROS) levels dose-dependently increased with GST enzyme activity. In addition, up-regulations of the antioxidant and chaperoning genes in response to gamma radiation were able to recover cellular damages, and life table parameters were significantly influenced, particularly with regard to fecundity. DNA repair-associated genes showed significantly up-regulated expression patterns in response to sublethal doses (150 and 200 Gy), as shown in the expression of the gamma-irradiated B. koreanus p53 gene, suggesting that these sublethal doses were not significantly fatal to B. koreanus but induced DNA damages leading to a decrease of the population size

  14. Copépodes, Cladocères et Rotifères du lac Sidi M'hamed Benali (Algérie Nord-Occidentale

    Directory of Open Access Journals (Sweden)

    Mohamed Ali Bouzidi

    2010-03-01

    Full Text Available En 2008, 33 espèces de Cladocères, Copépodes et Rotifères ont été observées dans le lac Sidi M'hamed Benali (contre 12 seulement en 1992.Les Copépodes dominent en mars, avril, juillet, août et septembre, avec respectivement des dominances (Do égales à : 56,6 %, 55,0 %, 55,0 %, 46,4 % et 90,0 %. Les Cladocères dominent en février (Do = 37,2 %, mai (Do = 47,4 % et décembre (Do = 48,6 %. Les Rotifères sont extrêmement abondants et présentent une large dominance en janvier (Do = 95,3 %. La population zooplanctonique est très faible en juillet et en août. Au cours de l'année le peuplement varie en fonction de la température, des conditions hydrologiques, de l'abondance de la nourriture et de la prédation par les poissons.In 2008, 33 species of Cladocers, Copepods and Rotifers have been observed in Sidi M’hamed Benali Lake (against only 12 species in 1992. The Copepods dominate in March, April, July, August and September, respectively with dominance (Do equal to 56.6 %, 55.0 %, 55.0 %, 46.4 % and 90.0 %. Cladocers dominated in February (Do = 37.2 %, May (Do = 47.4 % and December (Do = 48.6 %. The rotifers are extremely abundant and have a wide dominance in January (Do = 95.3%. The zooplankton population is very low in July and August. During the year, the population varies with temperature, water conditions, abundance of food and predation by fishes.

  15. Effects of the fungicide prochloraz on the rotifer Brachionus calyciflorus%杀真菌剂咪鲜安对萼花臂尾轮虫的影响

    Institute of Scientific and Technical Information of China (English)

    李大命; 陆正和; 封琦; 杨家新

    2011-01-01

    Recent reports suggested that when certain contaminants are present in aquatic ecosystem at levels higher the threshold , they would disrupt endocrine functions of a variety of aquatic invertebrates including rotifers. Prochloraz ( C15 H16C13N3 O2 ) was a new broad-spectrum fungicide developed by England Boots Company ( now called Agro Evo) in 1974 . and launched into the market in 1977. Previous studies have focused mainly on efficacy, toxicity, and fungicidal mechanism of prochloraz; however little information was available about its environmental hormone effect in aquatic ecosystem. This motivated us to use freshwater rotif'er Brachionus calyciflorus , which was distributed widely in lakes , ponds , rivers and other such aquatic ecosystems, as test species to examine whether the fungicide prochloraz can affect the population growth and cumulative egg production in the rotifers and show environmental activity. The effect of prochloraz on reproduction and life cycle characteristics in the rotifer B. calyciflorus was studied by using experimental methods under laboratory conditions. Neonate females of B. calyciflorus were ( 0 - 2 h old) hatched from resting eggs in EPA medium. This rotifer strain was originally collected in Huai-an , Jiangsu Province in China during 2002 ,and since then it has been cultured in the laboratory continuously with periodic collection and storage of resting eggs.ChLorella pyrenoidosa ( cultured in HB4 medium at 25℃) was fed to B. calyciflorus at a density 3. 0x106cells /mL at 25℃.in 3 L bags under fluorescent illumination of 4000 lux and photo period was 16 :8( L :D). The results showed that 24h median lethal concentration ( 24hLC50) value of prochloraz for B. calyciflorus was 7. 09 mg/L, and exhibited a linear regression relationship Y= 20. 6581X- 12. 5673 ( R2 = 0. 93 ) , 95% limits are 6. 95-7. 21 mg/L. Survival curves were lower in treatment groups than that in control, and they decreased with increasing chemical concentrations

  16. Real-time PCR detection and quantification of fish probiotic Phaeobacter strain 27-4 and fish pathogenic Vibrio in microalgae, rotifer, Artemia and first feeding turbot (Psetta maxima) larvae

    DEFF Research Database (Denmark)

    Prol, M.J.; Bruhn, Jesper Bartholin; Pintado, J.;

    2009-01-01

    and in presence of microalgae (Isochrysis galbana), rotifers (Brachionus plicatilis), Artemia nauplii or turbot (Psetta maxima) larvae by real-time PCR based on primers directed at genetic loci coding for antagonistic and virulence-related functions respectively. The optimized protocol was used to study...

  17. How does the 'ancient' asexual Philodina roseola (Rotifera : Bdelloidea) handle potential UVB-induced mutations?

    NARCIS (Netherlands)

    Fischer, Claus; Ahlrichs, Wilko H.; Buma, Anita G. J.; van de Poll, Willem H.; Bininda-Emonds, Olaf R. P.

    2013-01-01

    Like other obligate asexuals, bdelloid rotifers are expected to suffer from degradation of their genomes through processes including the accumulation of deleterious mutations. However, sequence-based analyses in this regard remain inconclusive. Instead of looking for historical footprints of mutatio

  18. Evolution: The End of an Ancient Asexual Scandal.

    Science.gov (United States)

    Schwander, Tanja

    2016-03-21

    Bdelloid rotifers were believed to have persisted and diversified in the absence of sex. Two papers now show they exchange genes with each other, via horizontal gene transfers as known in bacteria and/or via other forms of non-canonical sex. PMID:27003885

  19. 单巢类轮虫有性生殖的研究进展与展望%Sexual reproduction in monogonont rotifers: A review

    Institute of Scientific and Technical Information of China (English)

    孙栋; 牛翠娟

    2013-01-01

    This paper focuses on the recent findings of sexual reproduction in monogonont rotifers, which account for the main bulk of phylum Rotifera. Generally, they act as one of the major groups of primary consumers in freshwater ecosystem. Thus, studies on population dynamics and their mechanisms of monogonont rotifers may provide important data to both theoretical and applied research on freshwater ecosystems. As a group with parthenogenetic life history, sexual reproductive strategy in monogonont rotifers may profoundly affect their population dynamics and evolution. This review summarized several aspects of sexual reproduction in the monogonont rotifers, such as the mechanism, pheromones, models, influence factors, and particularly, empirical evidences. More specifically, we emphasized three models about their sexual reproduction patterns: " bang-bang" model, intermediate mictic ratios model and no-delaying mixis model. Then we summarized the exogenous and endogenous factors that affect sexual reproduction. The major exogenous factors include the concentration and type of food, temperature, salinity and special bacteria, while the major endogenous factors include the maternal age, a transgenerational maternal effect induced by food concentration, mixis delay and some potential maternal effects. We especially highlighted the model, mechanism and empirical evidences of mixis delay, since this phenomenon existed widely and was deem to be a potential explanation for species or clones coexistence. We also gave some personal views on the relationship between sex allocation theory and sexual reproduction in the monogonont rotifers. Finally, several potential hotspots in the future study were highlighted.%作为轮虫动物门的主体,单巢类轮虫是淡水浮游动物的重要组成部分.它们通常作为一类主要的初级消费者在淡水生态系统中起着重要作用,因而深入了解它们在自然水体中的种群动态及其决定机制对淡水生态系

  20. Study on feeding ecology of rotifer Brachionus urceus%壶状臂尾轮虫摄食生态的实验研究

    Institute of Scientific and Technical Information of China (English)

    冯蕾; 王进河; 唐学玺

    2009-01-01

    研究了壶状臂尾轮虫(Brachionus urceus)在不同的温度、盐度、饵料种类、pH和光照条件下滤水率(F)和摄食率(G)的变化情况.结果表明:(1)温度对壶状臂尾轮虫的摄食有显著影响(P>小球藻(Chlorella sp.)>牟氏角毛藻(Chaetoceros muelleri Lermumerman)>金藻8701(Isochrysis galbana Park 8701)>扁藻(Tetraselmis chuii);G的顺序为:小球藻>小新月菱形藻>金藻8701>牟氏角毛藻>扁藻;(4)壶状臂尾轮虫适宜的摄食pH范围为6.0~8.0,最适摄食pH为7.0; (5)在条件允许的情况下,黑暗有利于壶状臂尾轮虫的摄食.%The filtering and feeding rate of rotifer Brachionus urceus were studied under different temperature, salinity, food species, pH and light. The results showed that the filtering rate (F) and feeding rate (G) were significantly affected by temperature and salinity. The suitable temperature and salinity for feeding of Brachionus urceus ranged from 25℃ to 30℃ and from 20 to 30, the optimal temperature and salinity were 25℃ and 30. The filtering and feeding rate of Brachionus urceus for 5 strains of microalgae showed a declining gradient of Chaetoceros muelleri Lermumerman > Nitzschia clostertum > Isochrysis galbana Park 8701 >Chlorella sp. > Tetraselmis chuii and Chlorella sp. > Isochrysis galbana Park 8701 >Chaetoceros muelleri Lermumerman > Nitzschia clostertum > Tetraselmis chuii. The suitable pH for feeding of Brachionus urceus ranged from 6.0 to 8.0 and the optimal pH for feeding was 7.0. The darkness was suitable for feeding of rotifer Brachionus urceus.

  1. Triclosan (TCS) and Triclocarban (TCC) cause lifespan reduction and reproductive impairment through oxidative stress-mediated expression of the defensome in the monogonont rotifer (Brachionus koreanus).

    Science.gov (United States)

    Han, Jeonghoon; Won, Eun-Ji; Hwang, Un-Ki; Kim, Il-Chan; Yim, Joung Han; Lee, Jae-Seong

    2016-01-01

    Triclosan (TCS) and Triclocarban (TCC) are used as antimicrobial agents and have been widely dispersed and detected in the marine environment. However, the toxicities of TCS and TCC have been poorly investigated in marine invertebrates. In this study, the effects of TCS and TCC on mortality, population growth, lifespan, and fecundity were examined in the monogonont rotifer (Brachionus koreanus) using cellular ROS levels, GST enzymatic activity, and gene expression of defensomes. The median lethal concentration (LC50) of TCS (393.1μg/L) and TCC (388.1μg/L) was also determined in the same species. In TCS- and TCC-exposed B. koreanus, growth retardation and reduced fecundity were observed and were shown to have a potentially deleterious effect on the life cycle of B. koreanus. In addition, time-dependent increases in ROS content (%) and GST enzymatic activity were shown in response to TCS and TCC exposure. Additionally, transcript levels of detoxification proteins (e.g., CYPs), antioxidant proteins (e.g., GST-sigma, Cu/ZnSOD, CAT), and heat shock proteins (Hsps) were modulated in response to TCS and TCC exposure over a 24h period. Our results indicate that TCS and TCC induce oxidative stress and transcriptional regulation of detoxification, antioxidant, and heat shock proteins, resulting in changes in lifespan and fecundity. PMID:27067728

  2. Triclosan (TCS) and Triclocarban (TCC) cause lifespan reduction and reproductive impairment through oxidative stress-mediated expression of the defensome in the monogonont rotifer (Brachionus koreanus).

    Science.gov (United States)

    Han, Jeonghoon; Won, Eun-Ji; Hwang, Un-Ki; Kim, Il-Chan; Yim, Joung Han; Lee, Jae-Seong

    2016-01-01

    Triclosan (TCS) and Triclocarban (TCC) are used as antimicrobial agents and have been widely dispersed and detected in the marine environment. However, the toxicities of TCS and TCC have been poorly investigated in marine invertebrates. In this study, the effects of TCS and TCC on mortality, population growth, lifespan, and fecundity were examined in the monogonont rotifer (Brachionus koreanus) using cellular ROS levels, GST enzymatic activity, and gene expression of defensomes. The median lethal concentration (LC50) of TCS (393.1μg/L) and TCC (388.1μg/L) was also determined in the same species. In TCS- and TCC-exposed B. koreanus, growth retardation and reduced fecundity were observed and were shown to have a potentially deleterious effect on the life cycle of B. koreanus. In addition, time-dependent increases in ROS content (%) and GST enzymatic activity were shown in response to TCS and TCC exposure. Additionally, transcript levels of detoxification proteins (e.g., CYPs), antioxidant proteins (e.g., GST-sigma, Cu/ZnSOD, CAT), and heat shock proteins (Hsps) were modulated in response to TCS and TCC exposure over a 24h period. Our results indicate that TCS and TCC induce oxidative stress and transcriptional regulation of detoxification, antioxidant, and heat shock proteins, resulting in changes in lifespan and fecundity.

  3. Feeding ω-3 PUFA enriched rotifers to Galaxias maculatus (Jenyns, 1842 larvae reared at different salinity conditions: effects on growth parameters, survival and fatty acids profile

    Directory of Open Access Journals (Sweden)

    Patricio Dantagnan

    2013-07-01

    Full Text Available Despite the well known importance of ω-3 polyunsaturated fatty acids (PUFA in marine and freshwater fish larvae, there are few studies on how essential fatty acid requirements and composition on whole body can be altered by changes in water salinity. The present study aimed to determine the effect of salinity on ω-3 PUFA requirements, larval growth survival and fatty acid composition of Galaxias maculatus larvae cultured at two different salinities (0 and 15 g L-1 for 20 days while fed rotifers containing two different levels of ω-3 PUFA (1.87 and 3.16%. The results denoted a marked difference in ω-3 PUFA requirements and in the pattern of fatty acid deposition in the whole body of larvae reared at different salinities, depending of ω-3 PUFA in diets. Thus, to improve growth and survival larvae of G. maculatus reared at 0 g L-1 require higher levels of ω-3 PUFA, principally 18:3 ω-3. Larvae reared at salinities of 15 g L-1 require low levels of ω-3 PUFA for optimal survival, especially 18:3 ω-3. Eicosapentaenoic acid and docosahexaenoic acid content in the whole body of larvae was also affected by water salinity.

  4. Spatial-temporal Dynamics of Rotifer Community Structure in the Jinan Region%济南地区河流轮虫群落结构的时空动态研究

    Institute of Scientific and Technical Information of China (English)

    王博涵; 李晨; 姜力文; 陈鹏; 殷旭旺; 徐宗学

    2016-01-01

    探讨轮虫群落结构及与水质环境因子之间的关系,为合理开发济南地区水资源以及水环境污染治理提供可靠依据。2014年5月(春季)、8月(夏季)和10月(秋季)分别对济南地区19个站点采样调查,分析不同季节轮虫群落结构的分布特征,应用香农维纳指数和均匀度指数评价济南地区水质健康状况,典范对应分析法判定影响轮虫群落结构的主要环境因子。济南地区水体共鉴定出轮虫17属38种,以龟甲轮属和臂尾轮属为主,春季、夏季和秋季轮虫种类分别为30、17和9种,轮虫密度平均值为114.4、10和8.3个/L。轮虫污染指示种20种,其中寡污带3种、寡污至β中污型5种、β中污性8种、α中污型2种、β-α中污型2种;轮虫污染指示种类占总种类数的52.63%,密度占77.99%;春季出现污染指示种15种,夏季和秋季分别为11种和8种。春季的优势种为卵形彩胃轮虫,夏季的优势种为萼花臂尾轮虫,秋季的优势种为萼花臂尾轮虫、卜氏晶囊轮虫、前节晶囊轮虫。香农维纳指数平均值分别为2.67、1.38和1.20;均匀度指数平均值分别为0.66、0.41和0.35。典范对应分析结果,主要影响南部、中部和北部地区轮虫群落结构的环境因子,春季为总氮、氨氮和硬度,夏季为高锰酸钾,秋季为总磷。综合评价济南地区水生态呈中度污染。%Rotifers are important indicators of water quality and widely used for environment monitoring as they are highly sensitive to environmental change.During the spring,summer and autumn of 2014,we investigated the structure and diversity of the rotifer community in waters of the Jinan region.Water quality was evaluated and the relationship between rotifer community structure and environmental factors was analyzed.The study provides data to support scientific management of water resources and water pollution

  5. 不同脂肪源对褶皱臂尾轮虫脂类和脂肪酸组成的影响%Effects of dietary lipid sources on fatty acid composition of rotifer Brachionus plicatilis

    Institute of Scientific and Technical Information of China (English)

    成永旭; 王武; 吴嘉敏; 黄显清

    2001-01-01

    Rotifer Brachionus plicatilis was used as the test species. The diets with different lipid sources were as follows: ( 1 ) Baker' s yeast, Saccharomyces cerevisice (control); (2) algae, Nannochlorpsis oculata ( diet A);(3) fish oil(5%) + soybean lecithin (5%) + Baker's yeast(90%)(diet B); (4) fish oil (10%) + Baker's yeast(90 96 )(diet C). The results show that: (1) Considerable difference of fatty acid composition exists in the rotifers fed corresponding diets compared with control, and the highest level of n-3 HUFA fatty acids in the rotifers fed diet C is obtained due to high level of n-3HUFA content in diet. The conclusion is that the HUFA content of diet is a major factor in affecting HUFA levels in the rotifers. (2) The effect of dietary lipid on the fatty acid composition is not only based on dietary level of HUFA, but also the lipid chemical types. (3) The method using dried diet (yeast) mixed with fish oil for the rotifers to enrich n-3HUFA is suitable for large-scale rotifer production mainly for the good effect of HUFA enrichment and avoidance of water contamination.%以褶皱臂尾轮虫(Brachionus plicatilis)为实验动物并设计不同脂肪源饵料,分别为:面包酵母Saccharomyces cerevisice(对照组),微绿球藻Nannochlorpsis oculata(A),5%大豆磷脂+5%鱼油+90%面包酵母(B),10%鱼油+90%面包酵母(C).结果表明:(1)接受不同脂肪源的轮虫的脂肪酸组成显著不同,尤其是高度不饱和脂肪酸(HUFA,20C)含量存在显著差异,说明饵料中HUFA含量对轮虫体内相应脂肪酸的含量有显著影响.投喂饵料C的轮虫具有高含量的n-3HUFA(26.7%),而对照组轮虫的n-3HUFA只有7.56%,所以投喂饵料C使轮虫的脂类HUFA水平得到了强化,提高了轮虫的营养价值.(2)轮虫脂类的HUFA水平不仅由饵料中脂类的相应脂肪酸组成决定,而且轮虫脂类HUFA的提高和强化效果与饵料中HUFA的化学形态密切相关.甘油三酯型饵料HUFA的强化轮

  6. Effects of UV-B radiation on population growth of rotifer Brachionus urceus%UV-B辐射增强对壶状臂尾轮虫种群增殖的影响

    Institute of Scientific and Technical Information of China (English)

    王进河; 冯蕾; 唐学玺

    2009-01-01

    运用群体累计培养的方法研究了UV-B辐射增强对壶状臂尾轮虫(Brachionus urceus)种群增殖的影响.结果表明:UV-B辐射增强对壶状臂尾轮虫的种群数量、雌体抱卵率和种群增殖率都有显著影响(P<0.05).实验表明,在本实验辐射强度(20μW/cm2)和剂量范围内(0.24、0.48、0.72、0.96和1.20kJ/m2),壶状臂尾轮虫的种群数量和种群增殖率均以对照组最高,各UV-B辐射处理组则随UV-B辐射剂量的增大而呈一致性减小,说明该种群的种群数量和种群增殖率随UV-B辐射的增强显示一致性的影响,两者都可以作为大气UV-B辐射强弱的生物指标.%The effects of UV-B radiation on population growth of rotifer Brachionus urceus were studied using the method of population accumulative culture. The results showed that the population numbers, the percentage of egg-bearing females relative to the total number of females and population growth rate of rotifer Brachionus urceus were significantly affected by UV-B radiation (P<0.05). At the experimental intensity of 20μW/cm2and in the dose range studied (0.00, 0.24, 0.48, 0.72, 0.96 and 1.20kJ /m2), both the population number and growth rate was the highest in the control and decreased with the increment of UV-B radiation. In addition, the population number and growth rate of rotifer Brachionus urceus showed a similar tendency of decrease with the dose increase of UV-B radiation. Both of them could be used as an ideal biomarker for the enhancement of UV-B radiation.

  7. 广州低盐河段轮虫群落结构特征及富营养化状况分析%Rotifer communities structure and eutrophication analysis in the low salinity river segment,Guangzhou,South China

    Institute of Scientific and Technical Information of China (English)

    袁丹妮; 王庆; 陈亮东; 杨宇峰; 刘胜

    2014-01-01

    Rotifers are an important part of the zooplankton community and key links to the microbial food web in river ecosystems.They can also be used as important indicators of water quality.Samples were collected monthly from April 201 0 to March 201 3 ,at the Zhongda (S1 )and Yuzhu (S2 )sites a-long the Guangzhou segment of the Pearl River in Guangzhou City.Rotifer species composition and abun-dance were analyzed and physico-chemical parameters of water samples were measured.A total of 48 spe-cies were identified,34 of which were pollution indicator species.The dominant species,including Anu-raeopsis fissa,Lififerotrocha subtilis,Brachionus angularis,Trichocerca pusilla,Filinia novaezealandia, and Brachionus caudatus,belong to pollution tolerant species.Rotifer abundance ranged from 2 to 4 063 ind./L,the annual mean densities were (1 359.46 ±1 89.54)ind./L (S1 )and (1 058.61 ±1 56.1 6) ind./L (S2 ),respectively.During the investigation period,salinity was less than 1.5 ,however,the contents of TN and TP were at high level at the two sampling stations.The annual mean TN contents were (6.22 ±0.39 )mg/L (S1 )and (6.32 ±0.35 )mg/L (S2 ),and the mean TP contents were (0.84 ± 0.53)mg/L (S1 )and (0.83 ±0.09)mg/L (S2),respectively.The contents of TN and TP were not significantly difference at the two sampling stations.The concentrations of chlorophyl-a range from 7.68 to 21 5.33 μg/L,the annual mean contents were (56.25 ±45.31 )μg/L (S1 )and (49.77 ±7.1 4 )μg/L (S2),respectively.Statistical analysis showed that there was a positive correlation between chloro-phyll-a concentrations (x)and rotifer abundance (y)(P<0.05;y=629.750 +1 0.71 7x).Based on ecological factors and water quality assessment system,the Guangzhou segment of the Pearl River is seri-ously eutrophic.%轮虫是浮游动物群落的重要组成部分,在河流生态系统微食物网的物质传递和能量流动过程中扮演着重要角色,同时也是水质评价的重要指标之一.为研究

  8. 阳澄湖养蟹网围内外轮虫群落结构的变化及分析%The variation and analysis of rotifer community structure in and out of crab-net-pen closing in the Yangcheng Lake

    Institute of Scientific and Technical Information of China (English)

    陈立婧; 刘樵; 彭自然; 胡忠军; 薛俊增; 王武

    2011-01-01

    Rotifer species are cosmopolitan and the endemism is very low. They are highly susceptible to physical and chemical changes in their environment due to their small size and permeable integument, and they are known to be an important link between the microbial loop and higher trophic levels, so rotifer is an excellent indicator of the water status of a lake. Yangcheng Lake is one of the most important freshwater lakes in China. The total area of the lake is 119.04 km2,aquatic plants are dense providing a food source for crabs and the lake yields high numbers of the Chinese mitten crab(Eriocheir sinensis). Currently, although the ecological effects of the pen culture on the environment have received extensive attention,expert mainly focus on aquatic plants, physical and chemical factors, environmental effects and benthic animals, but rarely reported on the rotifer community structures. To date, no studies have been done on rotifers in Yangcheng Lake in detail. Thus, the aim of this study was to analyze the spatial and temporal variation of rotifer community structure and species diversity in net-pen closing and lake areas, in order to provide the data and theoretical basis for aquatic ecosystem of Yangcheng Lake, biodiversity conservation and sustainable development of ecological-pen-culture. Rotifer community structure and several feature parameters of water quality were investigated in 3 controlled sites in net-pen closing and lake areas of Yangcheng Lake, during June 2008 to May 2009. The relationship of rotifer community structure and environmental parameters was analyzed, various parameters were used to assess the water quality. The totals of 83 rotifer species were collected, belonging to 30 genera and 12 families. The study showed that the annual average density and biomass of 3 sites in net-pen closing were lower than those in lake areas, density exhibited significant positive correlations with temperature. The CCA biplot of samples and environmental

  9. 内分泌干扰物氰戊菊酯和有机锡对萼花臂尾轮虫生殖的影响%Effect of endocrine disruptors fenvalerate and TBTC on reproduction of rotifer Brachionus calyciflorus

    Institute of Scientific and Technical Information of China (English)

    朱玮阁; 郭瑞昕; 杨家新

    2009-01-01

    Endocrine disruptors (EDs) are a structurally diverse group of compounds that may adversely affect the health of humans, wildlife and fisheries, or their progeny by interaction with the endocrine system. Many EDs have been detected in aquatic environments, many of which are capable of disrupting endocrine functions of a variety of aquatic invertebrates. In the present study, the estrogenic compound Fenvalerate and androgenic compound TBTC were screened for their effect on the batch carrying eggs every parental rotifer (P),total numbers of eggs, offspring production, and mictic female production of the freshwater rotifer Brachionus calyciflorus. Treatment with Fenvalerate at concentrations (except 3.2μg/L) significantly increased the frequency of carrying 3 eggs (p<0.05).Treatments with Fenvalerate at concentrations of 3.2μg/L to 2000μg/L significantly increased the total number of eggs production compared to controls (p<0.05). Treatment with TBTC at 0.0016,0.04, 0.2 and 1μg/L resulted in a significantly higher frequency of females carrying 3 and 4 eggs compared to control (p<0.05), but the frequency of carrying 1 egg was lower than control. The total number of eggs and offspring were all significantly lower than control (0.0016μg/L excluded) (p<0.05). Moreover, the ratios of mictic female (MF%) of parents and the first generation (F1) were also affected by Fenvalerate and TBTC. MF% of parents and F1 was significantly lower than control only in the two lowest concentrations of Fenvalerate at 0.64μg/L and 3.2μg/L (p<0.01), but there was no difference between treatments and control in higher concentrations, and no effect on MF/AF (mictic females/amictic females) of the F1 as well. The concentrations of TBTC only over 5μg/L significantly affected the MF% of parental compared to control (p<0.01), but MF% of F1 was obviously affected at all concentrations except 0.2μg/L. The MF/AF of parents and F1 were quite similar. TBTC had a negative effect on total number

  10. Community structure of rotifers and ecological assessment of water quality in the tidal Guangzhou segment of the Pearl River%珠江广州河段轮虫群落结构特征与水质生态学评价

    Institute of Scientific and Technical Information of China (English)

    侯磊; 王庆; 杨宇峰

    2011-01-01

    2008年4月至2010年3月,对珠江广州河段2个站点(中大码头和鱼珠码头)轮虫群落结构进行每月一次的调查,同时测定了透明度、叶绿素、总氮、总磷等理化指标,利用非生物环境因子对水体的营养状况进行了评价,并通过轮虫种类组成、富营养型指示种数/贫营养型指示种数(E/O)指数对水质进行评价.调查期间,共记录轮虫66种,其中污染指示轮虫46种.优势种为微型多突轮虫、裂痕龟纹轮虫、西氏三肢轮虫、角突臂尾轮虫.轮虫丰度范围为69~5 200 ind./L,中大码头采样点丰度最高;高峰期均出现在枯水期.轮虫丰度与pH、氮磷比显著正相关(P<0.05),与温度显著负相关(P<0.05).根据水质生态学评价指标,珠江广州河段水体已达重度富营养水平,与非生物环境因子营养状态综合评价结果一致.%Community structure of rotifers was investigated at two different sites in the tidal Guangzhou segment of the Pearl River with monthly sampling from April 2008 to March 2010. Transparency, Chlorophyll a (Chl a), Total Nitrogen (TN), Total Phosphorus (TP) and other physicochemical parameters were also measured simultaneously. Trophic state of waters was evaluated through non-biologic environmental factors. Ecological assessment of water quality was also carried out through the analysis of species composition of rotifers and E/O index. During the survey period, 66 species of rotifer were recorded and 46 species belong to pollution indicator. Lififerotrocha subtilis, Anuraeopsis fissa, Filinia novaezealandiae and Brachionus angularis were the dominant species. The abundance of rotffers ranged from 69 to 5 200 ind./L with the highest value at Zhongda pier site, The peak value of abundance was observed in the dry season. There was significantly positive correlations between pH, nitrogen-phosphorus ratios and rotifers abundance (P < 0. 05 ). A significantly negative correlation was detected between

  11. Cladocers, Copepods and Rotifers in rice-fish culture handled with metsulfuron-methyl and azimsulfuron herbicides and carbofuran insecticide Cladocera, Copepoda e Rotifera em rizipiscicultura tratada com os herbicidas metsulfuron-metílico e azimsulfuron e o inseticida carbofuran

    Directory of Open Access Journals (Sweden)

    Jaqueline Ineu Golombieski

    2008-11-01

    Full Text Available This study determined the effects of metsulfuron-methyl, azimsulfuron and carbofuran in communities: Cladocers, Copepods and Rotifers that are present in irrigated rice farming with the rice-fish system. The field experiment was conducted in the 2004/05 growing season with eight treatments. The fish species were: Cyprinus carpio, Ctenopharyngodon idella and Aristichthys nobilis, introduced seven days after treatments were applied. Water samples were collected 17 days before and 1st, 3rd, 10th, 18th, 31th, 51th, and 75th days after the agrochemicals were applied for identification and evaluation of the zooplankton. The results indicated that the herbicides did not affect the zooplankton community studied and carbofuran insecticide application provoked negative effects in Cladocers. Copepods and Rotifers were slightly affected by carbofuran.O presente estudo determinou o efeito de metsulfuron-metílico, azimsulfuron e carbofuran nas comunidades: Cladocera, Copepoda e Rotifera presentes em lavouras de arroz irrigado com o sistema de rizipiscicultura. O experimento foi conduzido durante a safra agrícola 2004/05 com oito tratamentos. As espécies de peixes utilizadas foram: Cyprinus carpio, Ctenopharyngodon idella e Aristichthys nobilis, introduzidas sete dias após a aplicação dos tratamentos. Amostras de água foram coletadas 17 dias antes e no(s 1°, 3°, 10°, 18°, 31°, 51° e 75° dias após a aplicação dos tratamentos para a identificação e a avaliação de zooplâncton. Os resultados indicam que os herbicidas estudados não afetaram a comunidade zooplanctônica e a aplicação do inseticida carbofuran provocou efeitos negativos em Cladocera. Copepoda e Rotifera foram pouco afetados pelo carbofuran.

  12. Efecto de la estructuración por macrófitas y por recursos alimentarios en la distribución horizontal de tecamebas y rotíferos en un lago andino patagónico Effect of macrophytes and food resources on the horizontal distribution of testate amoebae and rotifers in an Andean-Patagonian lake

    Directory of Open Access Journals (Sweden)

    MARCELA BASTIDAS-NAVARRO

    2007-09-01

    con el aumento de la abundancia de la cianofita Coelosphaerium kuetzingianum. Las diferencias señaladas indican que los recursos alimentarios serían un factor determinante en la distribución de especies de tecamebas y rotíferos en el lago Escondido. Para estos zoopláncteres de pequeño tamaño las macrófitas litorales brindarían alimento al favorecer el incremento del fitoplancton de redThe presence of macrophytes in the littoral zone of lakes produces particular conditions including higher resource availability for consumers. For this reason, the littoral zone is generally the area with the highest diversity of lakes and rivers. In this work we studied the horizontal distribution of testate amoebae and rotifers in Lago Escondido (Argentina in relation to food resources availability. The study was carried out along a north-south transect that includes the littoral and the pelagic zone of the lake. Phytoplankton and zooplankton were sampled during summer and spring (2001-2003 in five sampling stations: one pelagic and four littoral. Rotifers and testate amoebae, as well as phytoplanktonic algae abundance and biomass were estimated. Food resources were classified as nanoplankton ( 20 μm and the biovolume of these fractions varied significantly within the pelagic and littoral zones of the lake. Nanoplankon dominated the pelagic zone and was mainly composed by nanoflagellates while net phytoplankton prevailed in the littoral zone and was composed by diatoms, cyanophytes and chlorophytes. The highest number of species and diversity of testate amoebae and rotifers were observed in the littoral stations; nevertheless, no significant differences between the zones colonized by different macrophytes were observed. The CCA analysis showed four different groups. Keratella cochlearis, Synchaeta spp., Polyarthra vulgaris and Collotheca mutabilis characterized the pelagic samples and were related with a high abundance of nanoplankton. On the other hand, rotifers like

  13. Evidence of weak habitat specialisation in microscopic animals.

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    Diego Fontaneto

    Full Text Available Macroecology and biogeography of microscopic organisms (any living organism smaller than 2 mm are quickly developing into fruitful research areas. Microscopic organisms also offer the potential for testing predictions and models derived from observations on larger organisms due to the feasibility of performing lab and mesocosm experiments. However, more empirical knowledge on the similarities and differences between micro- and macro-organisms is needed to ascertain how much of the results obtained from the former can be generalised to the latter. One potential misconception, based mostly on anedoctal evidence rather than explicit tests, is that microscopic organisms may have wider ecological tolerance and a lower degree of habitat specialisation than large organisms. Here we explicitly test this hypothesis within the framework of metacommunity theory, by studying host specificify in the assemblages of bdelloid rotifers (animals about 350 µm in body length living in different species of lichens in Sweden. Using several regression-based and ANOVA analyses and controlling for both spatial structure and the kind of substrate the lichen grow over (bark vs rock, we found evidence of significant but weak species-specific associations between bdelloids and lichens, a wide overlap in species composition between lichens, and wide ecological tolerance for most bdelloid species. This confirms that microscopic organisms such as bdelloids have a lower degree of habitat specialisation than larger organisms, although this happens in a complex scenario of ecological processes, where source-sink dynamics and geographic distances seem to have no effect on species composition at the analysed scale.

  14. Persistência na água e influência de herbicidas utilizados na lavoura arrozeira sobre a comunidade zooplanctônica de Cladocera, Copepoda e Rotifera Water persistence and influence of herbicides utilized in rice paddy about zooplankton community of Cladocers Copepods and Rotifers

    Directory of Open Access Journals (Sweden)

    Geovane Boschmann Reimche

    2008-02-01

    Full Text Available Em lavoura de arroz irrigado, é utilizada uma grande quantidade de agroquímicos que, dependendo da sua persistência a campo e toxicidade, podem contaminar corpos d’água e afetar organismos vivos. Com o objetivo de determinar o efeito de concentrações de campo dos herbicidas Clomazone, Quinclorac, Metsulfuron-methyl e Propanil na comunidade zooplanctônica (Cladocera, Copepoda e Rotifera, conduziu-se um experimento em viveiros de aqüicultura, de março a maio de 2005, na estação do outono. Nos dias 1°, 2°, 3°, 7°, 10°, 18°, 31° e 51° após a aplicação dos herbicidas, foram coletadas amostras de água para se determinarem parâmetros físico-químicos da água, concentração dos herbicidas e comunidade zooplanctônica. Os parâmetros médios da qualidade da água foram: oxigênio dissolvido (3,5mg L-1, temperatura (20,1°C, pH (6,0, dureza total (18mg L-1 de CaCO3 e alcalinidade total (9mg L-1 de CaCO3. A ordem decrescente de persistência dos herbicidas na água foi Clomazone = Quinclorac > Propanil > Metsulfuron-methyl, com média de 31, 31, 10 e 7 dias, respectivamente. Os resultados indicaram que os herbicidas provocaram poucas alterações na densidade de organismos dos grupos Rotifera e Copepoda (Adulto e Nauplio. A densidade do grupo Cladocera permaneceu baixa para todo o período experimental.In the rice paddy field it is used a large amount of agrochemical that, depending on their field persistence and toxicity, can contaminate water bodies and may affect living organism. With the objective of determining the effect of field concentrations of Clomazone, Quinclorac, Metsulfuron-methyl and Propanil herbicides on zooplankton community (Cladocers, Copepods and Rotifers, it was carried an experiment in aquaculture ponds, during March to May 2005, in autumn season. In the 1st, 2nd, 3rd, 7th, 10th, 18th, 31th and 51th days after the herbicides application, water samples were collected to evaluate the physical chemical water

  15. Substituição de Artemia sp. pelo rotífero Brachionus plicatilis na larvicultura do camarão-d'água-doce (Macrobrachium rosenbergii De Man, 1879 Replacement of the Artemia sp. for the rotifer Brachionus plicatilis in the hatchering of the freshwater prawn (Macrobrachium rosenbergii De Man, 1879

    Directory of Open Access Journals (Sweden)

    Luciana Almada Thomaz

    2004-12-01

    sp. for the enriched and frozen rotifer (Brachionus plicatilis O.F. Müller, 1786 on the larval development and survival of the freshwater prawn M. rosenbergii. The experiment was developed according to the following treatments: 100% B. plicatilis (30 rots/ mL (T1; 100% Artemia sp. (5 nas/ mL (T2, 60% Artemia sp. (3 nas/ mL + 40% B. plicatilis (12 rots/ mL (T3 e 40% Artemia sp. (2 nas/ mL + 60% B. plicatilis (18 rots/ mL (T4. Humid ration was added to all treatments. The results of the final survival in post-larvae were analyzed by the X² test and demonstrated no significant differences from treatment T2 (68.36% to T3 and T4: 68.76% and 64.60%, respectively. T1 treatment (100% B. plicatilis presented total mortality at 14th day of the experiment. Average dry weight of the pos-larvae was analyzed statistically by ANOVA and showed no significant differences in values: 3.29 mg (T2, 3.08 mg (T3 and 3.38 mg (T4. No significant differences among treatments T2, T3 and T4 were observed. The best mortality rate was observed from 1 to 15 day of hatchery based on the number of dead larval stored in the daily material siphoned. Therefore, these results suggest that the total substitution of the enriched and frozen rotifer is not recommended due to a total mortality of larvae, whereas the partial replacement of 40% and 60% of the Artemia sp nauplii by the enriched and frozen rotifer is possible, with no significant damages to survival and post-larval growth.

  16. Characterization of Summer Zooplankton (Rotifer and Crustacean)Community and Water Quality Assessment of Three Typical Nanchang Lakes%南昌市3个城中湖泊夏季轮虫和甲壳类群落特征及水质评价

    Institute of Scientific and Technical Information of China (English)

    文媛; 秦海明; 胡旭仁; 胡火玲

    2015-01-01

    With continuing development,urban lakes account for an increasing proportion of urban green space and serve several important functions including climate regulation,increased bio-diversity,flood control,and recrea-tion.However,domestic sewage discharge and other anthropogenic activities have caused severe eutrophication in urban lakes.Changes in the water environment have significantly influenced the zooplankton community in these lakes.Monitoring the zooplankton community dynamics and variation in species diversity provides a meaningful e-valuation of the water environment.In this study,the zooplankton community was characterised in three urban lakes in Nanchang during the summer of 2013,with emphasis on the density,abundance and diversity index of the rotifer and crustacean communities.The relationship between zooplankton distribution and environmental factors were ana-lyzed through multidimensional scaling analysis and canonical correspondence analysis.The pollution status of the three urban lakes was evaluated based on the Shannon-Wiener index,Pielou evenness index and species richness index of zooplankton.Zooplankton sampling was conducted in the open area of Donghu Lake,Qingshan Lake and Yueliang Lake on July 25,July 26 and August 10 of 2013,with three sampling sites in each lake and samples col-lected in triplicate at each site.Zooplankton were collected with a 2 L plankton sampler and filtered with a No.25 plankton net.The samples were then fixed and preserved with a mixture of Lugol's solution and 4% formalin for species identification and counting.The physiochemical parameters of the lakes were determined in situ with a multi-parameter water quality analyzer and included water temperature,pH,dissolved oxygen,chlorophyll-a and turbidity.Results show that rotifers dominated the three urban lakes and the dominant species were Brachionus for-ficula,Brachionus diversicornis,Brachionus calyciflorus,Copepod nauplii and Asplanchna brightwelli (dominance value Y

  17. Interactions between Ipomoea aquatica and Microbial Populations

    Institute of Scientific and Technical Information of China (English)

    Kan; Yuanqing; Sun; Ling; Zhang; Ying

    2014-01-01

    [Objective]This paper was to research the water purification mechanism of Ipomoea aquatica and its correlation with algae and rotifer. [Methods]Taking I. aquatica as the test material,Chlorella vulgaris,Scenedesmus obliquus,Microcystis aeroginosa and rotifer Adineta vaga with different densities were added to the hydroponics nutrients solutions of I. aquatica by the hydroponic ecological simulation method. The growth characteristics of I. aquatica,changes of microbial populations and the consumption status of nutrients in the nutritional solution were determined. And the interactions between the plant and the microbial populations were researched. [Results]When I. aquatica seedlings grew to a certain stage,growth of principal root stopped; while the lateral roots emerged greatly; and the nutrition absorption efficiency enhanced. As the inoculation concentration of C. vulgaris increased,root length of I. aquatica increased relatively great due to the competition for nutrients. The competition and allelopathy of M. aeroginosa and S. obliquus restricted the development of root system of I. aquatica. The grazing pressure of Chlorella vulgaris had little effects on M. aeroginosa,but restricted the rapid growth of S. obliquus. [Conclusions]This research provided data support for the application of fish-shrimp-vegetable aquaculture system.

  18. Life cycle traits of Philodina roseola Ehrenberg, 1830 (Rotifera, Bdelloidea), a model organism for bioassays.

    Science.gov (United States)

    Moreira, Raquel A; Mansano, Adrislaine S; Rocha, Odete

    2016-01-01

    This paper describes experimental results on the life cycle of the rotifer Philodina roseola cultured in the laboratory. Detailed information on life-cycle parameters of a certain species provides a deep understanding and contributes to a better knowledge of the role of the species in the community, besides providing data that are basic to other ecological investigations such as secondary production estimates and knowledge for applications such as its utilization as test-organism in ecotoxicological studies. The average duration of embryonic development of P. roseola was 23.88 h, the age at maturity of primipara was 3.5 days and the maximum lifespan was 23 days. The average size of the rotifer neonate was 198.77 µm, the mean size of primipara was 395.56 µm and for adults 429.96 µm. The average fecundity was 1.22 eggs per female per day and the mean number of eggs produced per female during the entire life was 22.33. The deceleration of somatic growth from the start of the reproductive stage represents a trade-off between growth and reproduction that is often seen in micrometazoans. The life history of P. roseola follows the strategy of other bdelloid species characterized by a rapid pre-reproductive development and canalization of most assimilated energy to reproduction after reaching maturity. The differences observed in total fecundity and longevity between our P. roseola cultures and those from previous studies were probably due to differences of intrinsic adaptation of this species ecotypes to the conditions of their natural environments. PMID:27168371

  19. Induction of hsp60 in the rotifer, Brachionus plicatilis exposed to dispersed and undispersed crude oil

    Energy Technology Data Exchange (ETDEWEB)

    Wheelock, C.; Tjeerdema, R.; Wolfe, M. [Univ. of California, Santa Cruz, CA (United States). Dept. of Chemistry and Biochemistry

    1995-12-31

    The use of chemical dispersants to treat oil spills remains a controversial area. Questions arise as to whether the dispersed oil is in fact more toxic than the original spill, potentially increasing the exposure of organisms in the water column to the dispersed components. Stress proteins, including hsp60, are a group of highly conserved proteins that are induced in response to a wide variety of environmental agents, including UV light, heavy metals, and xenobiotics. They are constitutively expressed, but Brachionus plicatilis has been used to document increased hsp60 levels in response to different environmental stresses. Hsp60 was therefore selected as a sublethal endpoint for B. plicatilis exposed to a range of concentrations of a water accommodated fraction (WAF) of Prudhoe Bay Crude Oil (PBCO), a PCBO/dispersant (Corexit 9527) fraction and a mixture of Corexit 9527 alone. All exposures were done at concentrations below the no observable effect level (NOEL) and at two different salinities, 22 ppt and 34 ppt. Laemmli SDS-PAGE techniques followed by Western Blotting using hsp60 specific antibodies and chemiluminescent detection were used to isolate, identify and measure induced hsp60 as a percentage of control values. Hsp60 induction exhibited a biphasic response with maximal induction occurring at lower concentrations of all three different mixtures, WAF, PBCO/Corexit 9527, and Corexit 9527 alone. Preliminary data found that the dispersed oil is indeed more toxic in terms of hsp60 induction than both the undispersed oil and the dispersing agent alone.

  20. Persistence, niche differentation and ecological similarity in two cryptic rotifer species

    OpenAIRE

    Gabaldón Tébar, Carmen

    2015-01-01

    La interacción entre especies competidoras y los procesos que intervienen y determinan el resultado de las dinámicas competitivas (i.e., coexistencia o exclusión) son temas fundamentales de estudio en ecología. La teoría establece que para que dos especies puedan persistir en el mismo hábitat y evitar la exclusión competitiva éstas deben tener diferentes requerimientos ecológicos (i.e., diferenciación de nicho). Sin embargo, la existencia de especies ecológicamente similares en simpatría pone...

  1. Peningkatan EPA dan DHA Rotifer (Brachionus plicatilis) oleh Bacillus sp. dengan Periode Pengkayaan Berbeda

    OpenAIRE

    Budi, Sutia; Zainuddin; Aslamyah, Siti

    2012-01-01

    Brachionus plicatilis memiliki beberapa kelebihan dibanding dengan pakan alami lainnya, seperti ukurannya yang relatif kecil, tetap bertahan di kolom air dan tidak mengendap, bergerak dengan kecepatan yang rendah dan laju perkembangbiakan yang cukup tinggi, merupakan pakan alami yang banyak dipergunakan usaha pembenihan. Penelitian ini bertujuan untuk melihat pengaruh pengkayaan dengan menambahkan Bacillus sp. Pada media kultur terhadap EPA dan DHA Nannochloropsis sp. dengan kepadatan 105 ce...

  2. The limnology and biology of the Dufek Massif, Transantarctic Mountains 82° South

    Science.gov (United States)

    Hodgson, Dominic A.; Convey, Peter; Verleyen, Elie; Vyverman, Wim; McInnes, Sandra J.; Sands, Chester J.; Fernández-Carazo, Rafael; Wilmotte, Annick; De Wever, Aaike; Peeters, Karolien; Tavernier, Ines; Willems, Anne

    2010-08-01

    Very little is known about the higher latitude inland biology of continental Antarctica. In this paper we describe the limnology and biology of the Dufek Massif, using a range of observational, microscopic and molecular methods. Here two dry valleys are home to some of the southernmost biota on Earth. Cyanobacteria were the dominant life forms, being found in lakes and ponds, in hypersaline brines, summer melt water, relict pond beds and in exposed terrestrial habitats. Their species diversity was the lowest yet observed in Antarctic lakes. Green algae, cercozoa and bacteria were present, but diatoms were absent except for a single valve; likely windblown. Mosses were absent and only one lichen specimen was found. The Metazoa included three microbivorous tardigrades ( Acutuncus antarcticus, Diphascon sanae and Echiniscus (cf) pseudowendti) and bdelloid rotifer species, but no arthropods or nematodes. These simple faunal and floral communities are missing most of the elements normally present at lower latitudes in the Antarctic which is probably a result of the very harsh environmental conditions in the area.

  3. A survey of PPR proteins identifies DYW domains like those of land plant RNA editing factors in diverse eukaryotes.

    Science.gov (United States)

    Schallenberg-Rüdinger, Mareike; Lenz, Henning; Polsakiewicz, Monika; Gott, Jonatha M; Knoop, Volker

    2013-01-01

    The pentatricopeptide repeat modules of PPR proteins are key to their sequence-specific binding to RNAs. Gene families encoding PPR proteins are greatly expanded in land plants where hundreds of them participate in RNA maturation, mainly in mitochondria and chloroplasts. Many plant PPR proteins contain additional carboxyterminal domains and have been identified as essential factors for specific events of C-to-U RNA editing, which is abundant in the two endosymbiotic plant organelles. Among those carboxyterminal domain additions to plant PPR proteins, the so-called DYW domain is particularly interesting given its similarity to cytidine deaminases. The frequency of organelle C-to-U RNA editing and the diversity of DYW-type PPR proteins correlate well in plants and both were recently identified outside of land plants, in the protist Naegleria gruberi. Here we present a systematic survey of PPR protein genes and report on the identification of additional DYW-type PPR proteins in the protists Acanthamoeba castellanii, Malawimonas jakobiformis, and Physarum polycephalum. Moreover, DYW domains were also found in basal branches of multi-cellular lineages outside of land plants, including the alga Nitella flexilis and the rotifers Adineta ricciae and Philodina roseola. Intriguingly, the well-characterized and curious patterns of mitochondrial RNA editing in the slime mold Physarum also include examples of C-to-U changes. Finally, we identify candidate sites for mitochondrial RNA editing in Malawimonas, further supporting a link between DYW-type PPR proteins and C-to-U editing, which may have remained hitherto unnoticed in additional eukaryote lineages. PMID:23899506

  4. The influence of different rotifer and Artemia enrichment diets on growth, survival and pigmentation in turbot (Scophthalmus maximus L.) larvae

    DEFF Research Database (Denmark)

    Støttrup, Josianne; Attramadal, Y.

    1992-01-01

    , approximately seven days after hatching, the larvae were fed newly-hatched Artemia salina nauplii (AT-1; Brazil strain). From day 10, enriched Great Salt Lake Artemia nauplii were introduced. Each set of seven tansk was further subdivided and the larvae fed Artemia nauplii enriched with one of four enrichment...

  5. Phaeobacter gallaeciensis Reduces Vibrio anguillarum in Cultures of Microalgae and Rotifers, and Prevents Vibriosis in Cod Larvae

    DEFF Research Database (Denmark)

    D'Alvise, Paul; Lillebø, Siril; Prol García, María Jesús;

    2012-01-01

    anguillarum was significantly reduced by wild-type P. gallaeciensis, when introduced into these cultures. A P. gallaeciensis mutant that did not produce the antibacterial compound tropodithietic acid (TDA) did not reduce V. anguillarum numbers, suggesting that production of the antibacterial compound...

  6. Niche segregation factors in an assemblage of pelagic rotifers of a deep high-mountain lake (Redon, Pyrenees)

    OpenAIRE

    Bartumeus, Frederic; Catalán, Jordi

    2008-01-01

    The niche space of a species has been defined as the region in N-dimensional environmental hyperspace in which the fitness of the individuals is positive. In zooplankton assemblages, there has been little consideration of how different density-dependent (i.e. resources) and density-independent (i.e. conditions) environmental factors relate to fitness components in the field, namely survival and reproduction. We studied the abundance and reproduction (egg ratio) variability of s...

  7. Distribution and diversity of soil microfauna from East Antarctica: assessing the link between biotic and abiotic factors.

    Directory of Open Access Journals (Sweden)

    Alejandro Velasco-Castrillón

    Full Text Available Terrestrial life in Antarctica has been described as some of the simplest on the planet, and mainly confined to soil microfaunal communities. Studies have suggested that the lack of diversity is due to extreme environmental conditions and thought to be driven by abiotic factors. In this study we investigated soil microfauna composition, abundance, and distribution in East Antarctica, and assessed correlations with soil geochemistry and environmental variables. We examined 109 soil samples from a wide range of ice-free habitats, spanning 2000 km from Framnes Mountains to Bailey Peninsula. Microfauna across all samples were patchily distributed, from complete absence of invertebrates to over 1600 specimens/gram of dry weight of soil (gdw, with highest microfauna abundance observed in samples with visible vegetation. Bdelloid rotifers were on average the most widespread found in 87% of sampled sites and the most abundant (44 specimens/gdw. Tardigrades occurred in 57% of the sampled sites with an abundance of 12 specimens/gdw. Nematodes occurred in 71% of samples with a total abundance of 3 specimens/gdw. Ciliates and mites were rarely found in soil samples, with an average abundance of 1.3 and 0.04 specimens/gdw, respectively. We found that microfaunal composition and abundance were mostly correlated with the soil geochemical parameters; phosphorus, NO3 (- and salinity, and likely to be the result of soil properties and historic landscape formation and alteration, rather than the geographic region they were sampled from. Studies focusing on Antarctic biodiversity must take into account soil geochemical and environmental factors that influence population and species heterogeneity.

  8. Environmental Sequencing of Biotic Components of Dust in the Chihuahuan Desert

    Science.gov (United States)

    Walsh, E.; Gill, T. E.; Rivas, J. A., Jr.; Leung, M. Y.; Mohl, J.

    2015-12-01

    A growing number of studies mark the role of wind in dispersing biota. Most of these approaches have used traditional methods to assess taxonomic diversity. Here we used next generation sequencing to characterize microbiota in dust collected from the Chihuahuan Desert. Atmospheric dust was collected during events during 2011-2014 using dry deposition collectors placed at two sites in El Paso Co., TX. In parallel experiments, we rehydrated subsamples of dust and conducted PCR amplifications using conserved primers for 16S and 18S ribosomal genes. Sequenced reads were de-multiplexed, quality filtered, and processed using QIIME. Taxonomy was assigned based on pairwise identity using BLAST for microbial eukaryotes. All samples were rarefied to a set number of sequences per sample prior to downstream analyses. Bioinformatic analysis of four of the dust samples yielded a diversity of biota, including zooplankton, bacteria, fungi, algae, and protists, but fungi predominate (>90% of both 10K and 3K reads). In our rehydrations of dust samples from the U.S. southwest nematodes, gastrotrichs, tardigrades, monogonont and bdelloid rotifers, branchiopods and numerous ciliates have been recovered. Variability in genetic diversity among samples is based, in part, on the source and extent of the particular dust event. We anticipate the same patterns will be seen in the complete data set. These preliminary results indicate that wind is a major transporter of not only fungi, bacteria and other unicellular organisms but may also be important in shaping the distribution patterns of multi-cellular organisms such as those that inhabit aquatic environments in the arid southwestern US.

  9. Integrative taxonomy: Combining morphological, molecular and chemical data for species delineation in the parthenogenetic Trhypochthonius tectorum complex (Acari, Oribatida, Trhypochthoniidae

    Directory of Open Access Journals (Sweden)

    Weigmann Gerd

    2011-02-01

    Full Text Available Abstract Background There is a long-standing controversial about how parthenogenetic species can be defined in absence of a generally accepted species concept for this reproductive mode. An integrative approach was suggested, combining molecular and morphological data to identify distinct monophyletic entities. Using this approach, speciation of parthenogenetic lineages was recently demonstrated for groups of bdelloid rotifers and oribatid mites. Trhypochthonius tectorum, an oribatid mite from the entirely parthenogenetic desmonomatan family Trhypochthoniidae, is traditionally treated as a single species in Central Europe. However, two new morphological lineages were recently proposed for some Austrian populations of T. tectorum, and were described as novel subspecies (T. silvestris europaeus or form (T. japonicus forma occidentalis. We used the morphological and morphometrical data which led to this separation, and added mitochondrial and nuclear DNA sequences and the chemical composition of complex exocrine oil gland secretions to test this taxonomical hypothesis. This is the first attempt to combine these three types of data for integrative taxonomical investigations of oribatid mites. Results We show that the previous European species T. tectorum represents a species complex consisting of three distinct lineages in Austria (T.tectorum, T. silvestris europaeus and T. japonicus forma occidentalis, each clearly separated by morphology, oil gland secretion profiles and mitochondrial cox1 sequences. This diversification happened in the last ten million years. In contrast to these results, no variation among the lineages was found in the nuclear 18S rDNA. Conclusions Our approach combined morphological, molecular and chemical data to investigate diversity and species delineation in a parthenogenetic oribatid mite species complex. To date, hypotheses of a general oribatid mite phylogeny are manifold, and mostly based on single-method approaches

  10. A Perspective on the Importance of Reproductive Mode in Astrobiology

    Science.gov (United States)

    Van Doninck, Karine; Schön, Isa; Martens, Koen

    2003-12-01

    Reproduction is a vital characteristic of life, and sex is the most common reproductive mode in the eukaryotic world. Sex and reproduction are not necessarily linked mechanisms: Sexuality without reproduction exists, while several forms of asexual reproduction are known. The occurrence of sexuality itself is paradoxical, as it is very costly in evolutionary terms. Most of the hypotheses (more than 20) attempting to explain the prevalence of sex fall into two categories: Sex either creates good gene combinations for adaptation to environments or eliminates bad gene combinations counteracting the accumulation of mutations. In spite of this apparent wealth of beneficial effects of sex, asexuality is not rare. Most eukaryotic, asexual lineages are short-lived and can only persist through the presence of sexual roots, but at least two animal groups, bdelloid rotifers and darwinulid ostracods, seem to claim the status of ancient asexuals. Research on (a)sexuality is relevant to astrobiology in a number of ways. First, strong relationships between the origin and persistence of life in extreme environments and reproductive mode are known. Second, the "habitability" of nonterrestrial environments to life greatly depends on reproductive mode. Whereas asexuals can do equally well or better in harsh environments, they fail to adapt fast enough to changing abiotic and biotic environments. Third, it has been shown that plants reproduce mainly asexually in space, and sperm production and motility in some vertebrates are hampered. Both findings indicate that extraterrestrial life under conditions different from Earth might be dominated by asexual reproduction. Finally, for exchange of biological material between planets, the choice of reproductive mode will be important.

  11. Parasitic success without sex – the nematode experience.

    Science.gov (United States)

    Castagnone-Sereno, P; Danchin, E G J

    2014-07-01

    Asexual reproduction is usually considered as an evolutionary dead end, and difficulties for asexual lineages to adapt to a fluctuating environment are anticipated due to the lack of sufficient genetic plasticity. Yet, unlike their sexual congeners, mitotic parthenogenetic root-knot nematode species, Meloidogyne spp., are remarkably widespread and polyphagous, with the ability to parasitize most flowering plants. Although this may reflect in part the short-term stability of agricultural environments, the extreme parasitic success of these clonal species points them as an outstanding evolutionary paradox regarding current theories on the benefits of sex. The discovery that most of the genome of the clonal species M. incognita is composed of pairs of homologous but divergent segments that have presumably been evolving independently in the absence of sexual recombination has shed new light on this evolutionary paradox. Together with recent studies on other biological systems, including the closely related sexual species M. hapla and the ancient asexual bdelloid rotifers, this observation suggests that functional innovation could emerge from such a peculiar genome architecture, which may in turn account for the extreme adaptive capacities of these asexual parasites. Additionally, the higher proportion of transposable elements in M. incognita compared to M. hapla and other nematodes may also be responsible in part for genome plasticity in the absence of sexual reproduction. We foresee that ongoing sequencing efforts should lead soon to a genomic framework involving genetically diverse Meloidogyne species with various different reproductive modes. This will undoubtedly promote the entire genus as a unique and valuable model system to help deciphering the evolution of asexual reproduction in eukaryotes.

  12. Parasitic success without sex – the nematode experience.

    Science.gov (United States)

    Castagnone-Sereno, P; Danchin, E G J

    2014-07-01

    Asexual reproduction is usually considered as an evolutionary dead end, and difficulties for asexual lineages to adapt to a fluctuating environment are anticipated due to the lack of sufficient genetic plasticity. Yet, unlike their sexual congeners, mitotic parthenogenetic root-knot nematode species, Meloidogyne spp., are remarkably widespread and polyphagous, with the ability to parasitize most flowering plants. Although this may reflect in part the short-term stability of agricultural environments, the extreme parasitic success of these clonal species points them as an outstanding evolutionary paradox regarding current theories on the benefits of sex. The discovery that most of the genome of the clonal species M. incognita is composed of pairs of homologous but divergent segments that have presumably been evolving independently in the absence of sexual recombination has shed new light on this evolutionary paradox. Together with recent studies on other biological systems, including the closely related sexual species M. hapla and the ancient asexual bdelloid rotifers, this observation suggests that functional innovation could emerge from such a peculiar genome architecture, which may in turn account for the extreme adaptive capacities of these asexual parasites. Additionally, the higher proportion of transposable elements in M. incognita compared to M. hapla and other nematodes may also be responsible in part for genome plasticity in the absence of sexual reproduction. We foresee that ongoing sequencing efforts should lead soon to a genomic framework involving genetically diverse Meloidogyne species with various different reproductive modes. This will undoubtedly promote the entire genus as a unique and valuable model system to help deciphering the evolution of asexual reproduction in eukaryotes. PMID:25105196

  13. Aeolian Transport of Invertebrates

    Science.gov (United States)

    Gill, T. E.; Walsh, E. J.; Wallace, R. L.; Rojo, L.; Rivas, J. A.

    2012-12-01

    Playas and other ephemeral desert wetlands are preferential terrestrial landforms for dust emission. These sites also are habitat for a diverse assemblage of minute invertebrates. When wetlands desiccate, these invertebrates survive as resting stages (propagules). Thus, playas serve as isolated, ephemeral, biogeographical islands for aquatic invertebrates, but it is unclear how propagules disperse across distances as far as hundreds of kilometers to colonize hydrologically disconnected basins. Aeolian transport (anemochory) may provide the mechanism, especially since many invertebrate propagules are long-lived, aerodynamically shaped, possess low-density, and their size (30-600 μm) falls within the same texture as aeolian dust and sand grains. We are collecting and culturing wind-transported sediment to document its ability to serve in the dispersal of aridland invertebrate propagules. Deposited aeolian sediment was collected from marble-type traps placed on the roof of the Biological Sciences Building at the University of Texas, El Paso, during 19 individual regional-scale Chihuahuan Desert blowing dust/sand events between April 2010 and May 2012. Known source areas for these dust events include playas and ephemeral streams ~40- 150 km upwind. The mean dry grain size of the deposited sediment for each event ranged from 66 to 141 μm. Clean-water rinses of material from each event or standard rehydrations for culturing invertebrates were monitored microscopically for the appearance of organisms. Invertebrates hatched from the sediment of 13 events. Ciliates were detected in each of those samples: gastrotrichs appeared in three samples, nematodes and bdelloid rotifers in two samples, and clam shrimp in one. We have also rehydrated aeolian sediments, collected in standard dust traps, from many dust-emitting playas in Southwest North America and hatched viable organisms including all those previously mentioned as well as branchiopods, fairy shrimp, copepods

  14. Feeding of rotifer Brachionus plicatilis enriched with microalgae.%营养强化时褶皱臂尾轮虫对饵料微藻的摄食

    Institute of Scientific and Technical Information of China (English)

    李磊; 朱小明; 吴洪喜

    2011-01-01

    选取适宜浓度利用单种微藻和混合微藻对轮虫进行营养强化,采用实验生态学方法研究了轮虫滤水率和摄食率的动态变化.结果表明:微藻浓度、微藻种类和培养时间均对轮虫的滤水率和摄食率有显著影响;轮虫对几种单种微藻的滤水率和摄食率均随培养时间的延长而下降,在实验条件下,6h内轮虫对3种微藻的滤水率大小顺序为小球藻>球等鞭金藻>牟氏角毛藻,12h内轮虫对3种和,微藻的滤水率大小顺序则为球等鞭金藻>小球藻>牟氏角毛藻;轮虫在混合微藻中的选择顺序为球等鞭金藻>小球藻>牟氏角毛藻.%By the methods of experimental ecology, this paper studied the dynamic changes of the filtration and ingestion rates of Brachionus plicatilis enriched with single and mixed microalgal diets at optimum concentrations. The microalgal concentration, microalgal species, and culture duration all had significant effects on the filtration and ingestion rates of B. Plicatilis. The filtration and ingestion rates of B. Plicatilis to the diets decreased with increasing culture duration. Under the experimental conditions, the filtration rate of B. Plicatilis to the microalgae within 6 hours was in the order of Chlorella sp- > Isochrysis galbana > Chaetoceros muelleri, while that within the whole experimental duration ( 12 hours) was Isochrysis galbana > Chlorella sp. > Chaetoceros muelleri. The predation of B. Plicatilis fed by mixed microalgal diet was with a preferential order of Isochrysis galbana > Chlorella sp. > Chaetoceros muelleri.

  15. High Density Cultivation of Rotifer Brachionus plicatilis by Baker's Yeast%用酵母高密度培养褶皱臂尾轮虫

    Institute of Scientific and Technical Information of China (English)

    王鸿鹄; 吴灶和; 瘳永岩

    2009-01-01

    用面包酵母室内高密度培养褶皱臂尾轮虫,结果发现,1.5 g/(106·d)的较高投饵量.适合于接种密度约为50个/ml的褶皱臂尾轮虫培养,而投饵量为1.0~1.2 g/(106·d)时.适合于200个/ml以上较高密度的褶皱臂尾轮虫培养.投饵量为1.5 g/(106·d)时.不适于500个/ml以上接种密度的褶皱臂尾轮虫培养.若褶皱臂尾轮虫密度继续高至1000个/ml以上,投喂量则需进一步降低至1 0 g/(106·d)以下.褶皱臂尾轮虫接种密度低至30个/ml以下时,除酵母外,适当添加一定量(1/3以上体积)的单胞藻.可提高褶皱臂尾轮虫的增殖速度,降低褶皱臂尾轮虫培育的风险.

  16. A scientific curiosity: viviparous reproduction in an activated sludge rotifer; Una curiosidad para la ciencia: reproduccion vivipara en un rotifero del fango activado

    Energy Technology Data Exchange (ETDEWEB)

    Zornoza, A.; Rodriguez, E.; Isac, L.; Fernandez, N.; Salas, M. D.

    2004-07-01

    This article offers reader the opportunity to witness a marvel of nature: the birth of a new being. It, in addition, it is borne in mind that we are talking about an organisms measuring less than 500?m and with a life span of just a few days, this is, to say the least, an unforgettable experience. We are in the presence of the miracle of life the microscopic level. This communication provides the chance to find out more about the physiology of this type of animal- the whet- el animalcule which is part of the micro fauna of activated sludge. (Author) 13 refs.

  17. Dicty_cDB: Contig-U12990-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ne) Adineta vaga clone Av240_A TPR rep... 36 1.00 DQ437593_33( DQ437593 |pid:none) Cowpox virus strain Ger...many 91-3,... 36 1.00 AF005381_1( AF005381 |pid:none) Homo sapiens ectoderm-neural

  18. Effects of UV-B radiation on the feeding of the rotifer Brachionus plicatilis%UV-B辐射增强对褶皱臂尾轮虫摄食的影响

    Institute of Scientific and Technical Information of China (English)

    冯蕾; 韩洪蕾; 唐学玺

    2007-01-01

    运用生态毒理学方法,研究了UV-B辐射条件下褶皱臂尾轮虫(Brachinonus plicatilis)对6株海洋微藻:小球藻(Chlorella sp.、绿色巴夫藻(Pauloua uiridis)、扁藻(Tetraselmis chuii)、球等鞭金藻8701(Isochrysis galbana Park 8701)、牟氏角毛藻(Chaetoceros muelleri Lermumerman)和小新月菱形藻(Nitzschia clostertum)的摄食.结果表明:UV-B辐射增强对褶皱臂尾轮虫的摄食有显著的抑制作用.与对照组相比,褶皱臂尾轮虫对每一种饵料单胞藻的滤水率和摄食率都表现出,随UV-B辐射剂量的增大而显著减小(P<0.5).而且对每一种饵料单胞藻的滤水率和摄食率是不相同的,这说明褶皱臂尾轮虫对饵料单胞藻是有选择性的.

  19. 双酚A对萼花臂尾轮虫毒性及生活史的影响%Effects of bisphenol A on the toxicity and life history of the rotifer Brachionus calyciflorus

    Institute of Scientific and Technical Information of China (English)

    陆正和; 赵宝坤; 杨家新

    2012-01-01

    应用生态毒理学研究方法,研究了双酚A(BPA)对萼花臂尾轮虫毒性及生活史影响.结果表明:BPA对萼花臂尾轮虫24h急性毒性LC50为13.76 mg/L,95%置信限为10.97-17.10 mg/L.生活史研究显示:与对照组相比,0.25-4.0 mg/L的BPA对轮虫胚胎发育历时影响不显著;2.0-4.0 mg/L的BPA显著延迟了轮虫幼体发育时间;当BPA为0.5 mg/L时,轮虫净生殖率(R0)显著上升,但BPA浓度为2.0和4.0 mg/L时R0显著降低;4.0 mg/L的BPA显著缩短世代时间(T);BPA浓度为2.0、4.0 mg/L时,轮虫生命期望值(e0)显著下降;BPA浓度为1.0、2.0、4.0 mg/L时,轮虫内禀增长率(rm)显著下降;BPA浓度为0.5、1.0 mg/L时轮虫所产后代混交率(MR)显著增长.研究结果表明BPA对轮虫的生殖具有干扰作用,其中R0和MR受BPA影响最为显著.

  20. DISCUSSION ON TECHNICAL TERMS RELATED TO HATCHING THE ROTIFER RESTING EGGS%关于轮虫休眠卵孵化的若干术语的探讨

    Institute of Scientific and Technical Information of China (English)

    周利; 相建海

    2001-01-01

    @@ 咸淡水轮虫(主要指褶皱臂尾轮虫plicatilis和圆形臂尾轮虫B. rotundiformis)是目前海水鱼类及甲壳类动物种苗培育的重要活饵料.轮虫休眠卵作为最理想的轮虫储存形式,其在水产养殖中的应用价值和经济意义深受各国学者的关注,休眠卵的“休眠”和“孵化”等相关生物学内容亦得到广泛深入的研究.其中关于孵化问题,郑严等1979年、1991年①、1994年②,王堉等1980年,Balopapueng等1997年[3],Gilbert 1974年,Hagiwara等1985、1989、1990、1995年,Minkoff等1983年,Pourriot等1993年已就各种内外因素对休眠卵孵化的影响进行了大量探讨.

  1. Diversité spécifique et abondance des communautés de copépodes, cladocères et rotifères des lacs du complexe Ossa (Dizangué, Cameroun

    Directory of Open Access Journals (Sweden)

    Joseph Guy Nziéleu Tchapgnouo

    2012-06-01

    Full Text Available La composition et la structure du zooplancton de deux lacs du complexe lacustre Ossa (Ossa et Mwembè, site protégé UNESCO situé dans une plaine inondable, ont fait l'objet d'une étude entre septembre 2009 et février 2010. 37 et 41 espèces de zooplancton ont été recensées respectivement dans les lacs Ossa et Mwembè. Les deux milieux, oligotrophes, sont soumis à l'influence du fleuve Sanaga qui leur apporte en temps de crue de nouvelles espèces. La présence de Mesocyclops leuckarti dans ces eaux amène à considérer l'existence de cette espèce sur le continent africain. La densité des organismes zooplanctoniques augmente entre septembre et novembre et chute rapidement en décembre, ce qui s'accorde avec une succession saisonnière des communautés. Les paramètres physico-chimiques, qui permettent de caractériser les plans d'eau comme oligotrophes, ne diffèrent pas significativement entre les deux milieux, ni avec la profondeur de prélèvement, ce qui justifie la valeur de 82 % trouvée pour l'indice de similitude de SÖRENSEN. Quant à la structure des populations de zooplancton, elle est influencée principalement par la saison et par la profondeur de prélèvement, le mois et la station n'ayant pas d'influence sur cette distribution.The composition and the structure of the zooplankton of two lakes of the Ossa lake complex (Ossa and Mwembe were studied between September 2009 and February 2010. 37 and 41 species of zooplankton were inventoried respectively in the lakes Ossa and Mwembe. The two environments are oligotrophic but subjected to the influence of the river Sanaga that brings them in swelling time new species. Mesocyclops leuckarti found in these lakes suggests the presence of this species on the African continent. The density of the zooplankton organisms increases between September and November and falls quickly in December, in accordance with a seasonal impact on communities. The physicochemical parameters do not differ significantly between the two environments and with the sampling depth. This justifies the value of 82 % obtained with the SÖRENSEN index. The structure of the populations of zooplankton is principally influenced by the season. The sampling depth, the month and the station do not influence this distribution.

  2. 充分发挥轮虫和卤虫在海水育苗中的营养作用%Fully understand the status and function of rotifer and brine shrimp in marine seed rearing

    Institute of Scientific and Technical Information of China (English)

    邹日瑞; 李向忠

    2003-01-01

    @@ 随着海水养殖业的发展,近些年来,轮虫和卤虫及其无节幼体,由于其适口性好、蛋白含量高、对水质无污染等优点,已被广泛地应用于海水鱼虾蟹类的苗种生产,已成为不可替代的活饵料生物.

  3. Feeding Results on Red Drum Sciaenops ocellatus Larvae Rearing with Taurine-enriched Rotifers%牛磺酸强化轮虫对眼斑拟石首鱼仔鱼的投喂效果

    Institute of Scientific and Technical Information of China (English)

    王秋荣; 竹内俊郎; 陈振湘

    2006-01-01

    研究用3种不同质量浓度梯度(分别为T0组:0 mg/L;T4组:400 mg/L;T8组:800mg/L)牛磺酸强化的轮虫(Brachionus plicatilis)对3~20日龄的眼斑拟石首鱼(Sciaenops ocellatus)仔鱼的投喂效果.结果表明,T8组的仔鱼平均全长((8.5±0.8)mm)和成活率(70.5%)都明显高于T0组(平均全长:(6.3±1.0)mm;成活率:28.4%)和T4组(平均全长:(7.0±0.8)mm;成活率:27.4%),T0组和T4组之间生长和成活率并无显著差异;T8组仔鱼的耐干露及耐高盐度(65)能力明显比T0组和T4组强,即仔鱼的抗应激能力受轮虫强化剂牛磺酸的质量浓度影响显著(P<0.05).

  4. AcEST: BP918016 [AcEST

    Lifescience Database Archive (English)

    Full Text Available A7P4N6|A7P4N6_VITVI Chromosome chr4 scaffold_6, whole genome ... 50 6e-05 tr|B3G4K0|B3G4K0_9BILA PIF/Harbinge...PVVLGACCVLHNICELQNEEMDPE 441 >tr|B3G4K0|B3G4K0_9BILA PIF/Harbinger-like protein OS=Adineta vaga PE=4 SV=1 Le

  5. AcEST: BP917988 [AcEST

    Lifescience Database Archive (English)

    Full Text Available 6e-05 tr|B3G4K0|B3G4K0_9BILA PIF/Harbinger-like protein OS=Adineta vag... 50 6e-05 tr|B7QE74|B7QE74_IXOSC T...++ + E Sbjct: 395 AFARLKARWCCLQKRTEVKLQDLPVVLGACCVLHNICELQNEEMDPE 441 >tr|B3G4K0|B3G4K0_9BILA PIF/Harbinger-

  6. Use of Copper to Selectively Inhibit Brachionus calyciflorus (Predator Growth in Chlorella kessleri (Prey Mass Cultures for Algae Biodiesel Production

    Directory of Open Access Journals (Sweden)

    Vishnupriya Pradeep

    2015-08-01

    Full Text Available A single Brachionus rotifer can consume thousands of algae cells per hour causing an algae pond to crash within days of infection. Thus, there is a great need to reduce rotifers in order for algal biofuel production to become reality. Copper can selectively inhibit rotifers in algae ponds, thereby protecting the algae crop. Differential toxicity tests were conducted to compare the copper sensitivity of a model rotifer—B. calyciflorus and an alga, C. kessleri. The rotifer LC50 was <0.1 ppm while the alga was not affected up to 5 ppm Cu(II. The low pH of the rotifer stomach may make it more sensitive to copper. However, when these cultures were combined, a copper concentration of 1.5 ppm was needed to inhibit the rotifer as the alga bound the copper, decreasing its bioavailability. Copper (X ppm had no effect on downstream fatty acid methyl ester extraction.

  7. Benthic‐pelagic coupling drives non‐seasonal zooplankton blooms and restructures energy flows in shallow tropical lakes

    Science.gov (United States)

    Schagerl, Michael; Yasindi, Andrew; Singer, Gabriel; Kaggwa, Mary Nakabungo; Winder, Monika

    2016-01-01

    Abstract Zooplankton blooms are a frequent phenomenon in tropical systems. However, drivers of bloom formation and the contribution of emerging resting eggs are largely unexplored. We investigated the dynamics and the triggers of rotifer blooms in African soda‐lakes and assessed their impact on other trophic levels. A meta‐analysis of rotifer peak densities including abundances of up to 6 × 105 individuals L−1 demonstrated that rotifer bloom formation was uncoupled from the food environment and the seasonality of climatic conditions. A time series with weekly sampling intervals from Lake Nakuru (Kenya) revealed that intrinsic growth factors (food quality and the physicochemical environment) significantly affected rotifer population fluctuations, but were of minor importance for bloom formation. Instead, rotifer bloom formation was linked to sediment resuspension, a prerequisite for hatching of resting‐eggs. Population growth rates exceed pelagic birth rates and simulations of rotifer dynamics confirmed the quantitative importance of rotifer emergence from the sediment egg‐bank and signifying a decoupling of bloom formation from pelagic reproduction. Rotifer blooms led to a top‐down control of small‐sized algae and facilitated a switch to more grazing‐resistant, filamentous cyanobacteria. This shift in phytoplankton composition cascaded up the food chain and triggered the return of filter‐feeding flamingos. Calculations of consequent changes in the lake's energy budget and export of aquatic primary production to terrestrial ecosystems demonstrated the large potential impact of nonseasonal disturbances on the functioning of shallow tropical lakes.

  8. First study on the zooplankton of the Kerid (Kerið Crater Lake, Iceland

    Directory of Open Access Journals (Sweden)

    Vesela Evtimova

    2014-04-01

    Full Text Available We studied the qualitative composition of zooplankton of the Kerid Crater Lake. We found 10 taxa from which five rotifers and two lower crustaceans. Three of the recorded species are new to the freshwater fauna of Iceland: the rotifer species Keratella cf. americana Carlin, 1943 and Colurella sulcata (Stenroos, 1898, and the crustacean harpacticoid Bryocamptus (Bryocamptus minutus (Claus, 1863.

  9. Cholinergic neuromuscular junctions in Brachionus calyciflorus and Lecane quadridentata (Rotifera:Monogononta)

    Institute of Scientific and Technical Information of China (English)

    Ignacio Alejandro Prez-Legaspi; Alma Lilin Guerrero-Barrera; Ivn Jos Galvn-Mendoza; Jos Luis Quintanar; Roberto Rico-Martnez

    2014-01-01

    Objective:To identify the presence of joint muscular and cholinergic systems in two freshwater rotifer species, Brachionus calyciflorus and Lecane quadridentata. Methods: The muscle actin fibers were stained with phalloidin-linked fluorescent dye, and acetylcholine was detected with Amplex Red Acetylcholine/Acetylcholinesterase Assay Kit, and then confocal scanning laser microscopy was used. Results:The musculature of Brachionus calyciflorus showed a pattern similar to other species of the same genus, while that of Lecane quadridentata was different from other rotifer genera described previously. The cholinergic system was determined by co-localization of both muscles and acetylcholine labels in the whole rotifer, suggesting the presence of neuromuscular junctions. Conclusions: The distribution pattern of muscular and acetylcholine systems showed considerable differences between the two species that might be related to different adaptations to particular ecological niches. The confirmation of a cholinergic system in rotifers contributes to the development of potential neuro-pharmacological and toxicological studies using rotifers as model organism.

  10. 两种桡足类对蟹苗池中轮虫的影响及其控制与利用%Effects of Two Copepod Species on Rotifer Brachionus Plicatilis and Control and Utilization of the Copepods in Mitten-handed Crab Larvae Breeding Earthen Ponds

    Institute of Scientific and Technical Information of China (English)

    张清靖; 周竹君; 朱华

    2005-01-01

    试验结果表明, 细巧华哲水蚤和近亲真宽水蚤严重影响轮虫的存活率;采用1.50、1.75,2.00 mg/L的敌百虫溶液2~3 h能杀死桡足类成体和幼体,但在该浓度下杀灭桡足类的无节幼体则需要7.5~14.5 h.用以上浓度的敌百虫溶液浸泡过的近亲真宽水蚤的卵提前同步萌发,据此提出"二次杀灭法",以有效地控制和利用蟹苗池中的桡足类.

  11. RESPONSES OF ZOOPLANKTON AND CHAOBORUS TO TEMEPHOS IN A NATURAL POND AND IN THE LABORATORY

    Science.gov (United States)

    Application of the organophosphorus insecticide temephos to a natural pond in central Minnesota was followed by reduction within 24 hr in all cladocerans, in Diaptomus leptopus and in Chaoborus americanus, and increases in cyclopoid copepods, copepod nauplii and rotifer Keratella...

  12. Enhanced rates of particulate organic matter remineralization by microzooplankton are diminished by added ballast minerals

    Directory of Open Access Journals (Sweden)

    F. A. C. Le Moigne

    2013-02-01

    Full Text Available To examine the potentially competing influences of microzooplankton and calcite mineral ballast on organic matter remineralization, we incubated diatoms in darkness in rolling tanks with and without added calcite minerals (coccoliths and microzooplankton (rotifers. Concentrations of particulate organic matter (POM, suspended or in aggregates, of dissolved organic matter (DOM, and of dissolved inorganic nutrients were monitored over 8 days. The presence of rotifers enhanced the remineralization of ammonium and phosphate, but not dissolved silicon, from the biogenic material, up to 40% of which became incorporated into aggregates early in the experiment. Added calcite resulted in rates of excretion of ammonium and phosphate by rotifers that were depressed by 67% and 36%, respectively, demonstrating the potential for minerals to inhibit the destruction of POM in the water column by zooplankton. Lastly, the presence of the rotifers and added calcite minerals resulted in more rapid kinetics of aggregation, although not a greater overall amount of aggregation during the experiment.

  13. Enhanced rates of particulate organic matter remineralization by microzooplankton are diminished by added ballast minerals

    OpenAIRE

    Moigne, F. A. C.; Gallinari, M.; Laurenceau, E.; Rocha, C L

    2013-01-01

    International audience; To examine the potentially competing influences of microzooplankton and calcite mineral ballast on organic matter remineralization, we incubated diatoms in darkness in rolling tanks with and without added calcite minerals (coccoliths) and microzooplankton (rotifers). Concentrations of particulate organic matter (POM in suspension or in aggregates), of dissolved organic matter (DOM), and of dissolved inorganic nutrients were monitored over 8 days. The presence of rotife...

  14. Copepods enhance nutritional status, growth and development in Atlantic cod (Gadus morhua L.) larvae - can we identify the underlying factors?

    Science.gov (United States)

    Karlsen, Ørjan; van der Meeren, Terje; Rønnestad, Ivar; Mangor-Jensen, Anders; Galloway, Trina F; Kjørsvik, Elin; Hamre, Kristin

    2015-01-01

    The current commercial production protocols for Atlantic cod depend on enriched rotifers and Artemia during first-feeding, but development and growth remain inferior to fish fed natural zooplankton. Two experiments were conducted in order to identify the underlying factors for this phenomenon. In the first experiment (Exp-1), groups of cod larvae were fed either (a) natural zooplankton, mainly copepods, increasing the size of prey as the larvae grew or (b) enriched rotifers followed by Artemia (the intensive group). In the second experiment (Exp-2), two groups of larvae were fed as in Exp-1, while a third group was fed copepod nauplii (approximately the size of rotifers) throughout the larval stage. In both experiments, growth was not significantly different between the groups during the first three weeks after hatching, but from the last part of the rotifer feeding period and onwards, the growth of the larvae fed copepods was higher than that of the intensive group. In Exp-2, the growth was similar between the two copepod groups during the expeimental period, indicating that nutrient composition, not prey size caused the better growth on copepods. Analyses of the prey showed that total fatty acid composition and the ratio of phospholipids to total lipids was slightly different in the prey organisms, and that protein, taurine, astaxanthin and zinc were lower on a dry weight basis in rotifers than in copepods. Other measured nutrients as DHA, all analysed vitamins, manganese, copper and selenium were similar or higher in the rotifers. When compared to the present knowledge on nutrient requirements, protein and taurine appeared to be the most likely limiting nutrients for growth in cod larvae fed rotifers and Artemia. Larvae fed rotifers/Artemia had a higher whole body lipid content than larvae fed copepods at the end of the experiment (stage 5) after the fish had been fed the same formulated diet for approximately 2 weeks. PMID:26038712

  15. Tolerance of sewage treatment plant microorganisms to mosquitocides.

    Science.gov (United States)

    Tietze, N S; Olson, M A; Hester, P G; Moore, J J

    1993-12-01

    Beneficial protozoa and rotifers collected from a wastewater treatment plant in Panama City, FL, were tested for tolerance to 11 commonly used mosquito larvicides and adulticides in the laboratory. The acute effects were assessed using selected concentrations of the adulticides fenthion, malathion, naled, permethrin, and resmethrin; and the larvicides Bacillus thuringiensis israelensis, Bacillus sphaericus, diflubenzuron, larviciding oil, methoprene, and temephos for the following microorganism taxa: ameoboids, flagellates, free-swimming ciliates, stalked ciliates, and rotifers. PMID:8126488

  16. Copepods enhance nutritional status, growth and development in Atlantic cod (Gadus morhua L.) larvae – can we identify the underlying factors?

    OpenAIRE

    Ørjan Karlsen; Terje van der Meeren; Ivar Rønnestad; Anders Mangor-Jensen; Galloway, Trina F.; Elin Kjørsvik; Kristin Hamre

    2015-01-01

    The current commercial production protocols for Atlantic cod depend on enriched rotifers and Artemia during first-feeding, but development and growth remain inferior to fish fed natural zooplankton. Two experiments were conducted in order to identify the underlying factors for this phenomenon. In the first experiment (Exp-1), groups of cod larvae were fed either (a) natural zooplankton, mainly copepods, increasing the size of prey as the larvae grew or (b) enriched rotifers followed by Artemi...

  17. Copepods enhance nutritional status, growth and development in Atlantic cod (Gadus morhua L. larvae — can we identify the underlying factors?

    Directory of Open Access Journals (Sweden)

    Ørjan Karlsen

    2015-05-01

    Full Text Available The current commercial production protocols for Atlantic cod depend on enriched rotifers and Artemia during first-feeding, but development and growth remain inferior to fish fed natural zooplankton. Two experiments were conducted in order to identify the underlying factors for this phenomenon. In the first experiment (Exp-1, groups of cod larvae were fed either (a natural zooplankton, mainly copepods, increasing the size of prey as the larvae grew or (b enriched rotifers followed by Artemia (the intensive group. In the second experiment (Exp-2, two groups of larvae were fed as in Exp-1, while a third group was fed copepod nauplii (approximately the size of rotifers throughout the larval stage. In both experiments, growth was not significantly different between the groups during the first three weeks after hatching, but from the last part of the rotifer feeding period and onwards, the growth of the larvae fed copepods was higher than that of the intensive group. In Exp-2, the growth was similar between the two copepod groups during the expeimental period, indicating that nutrient composition, not prey size caused the better growth on copepods. Analyses of the prey showed that total fatty acid composition and the ratio of phospholipids to total lipids was slightly different in the prey organisms, and that protein, taurine, astaxanthin and zinc were lower on a dry weight basis in rotifers than in copepods. Other measured nutrients as DHA, all analysed vitamins, manganese, copper and selenium were similar or higher in the rotifers. When compared to the present knowledge on nutrient requirements, protein and taurine appeared to be the most likely limiting nutrients for growth in cod larvae fed rotifers and Artemia. Larvae fed rotifers/Artemia had a higher whole body lipid content than larvae fed copepods at the end of the experiment (stage 5 after the fish had been fed the same formulated diet for approximately 2 weeks.

  18. Lake St. Clair zooplankton: Evidence for post-dreissena changes

    Science.gov (United States)

    David, K.A.; Davis, B.M.; Hunter, R.D.

    2009-01-01

    We surveyed the zooplankton of Lake St. Clair at 12 sites over ten dates from May to October 2000. Mean zooplankton density by site and date was 168.6 individuals/L, with Dreissena spp. veligers the most abundant taxon at 122.7 individuals/L. Rotifers, copepods, and cladocerans were far lower in mean abundance than in the early 1970s (rotifers, 20.9/L; copepods, 18.1/L; and cladocerans, 6.8/L). Species richness of zooplankton taxa in 2000 was 147, which was virtually unchanged from that of the first reported survey in 1894. Overall, the decline in abundance was greatest for rotifers (-90%) and about equal for cladocerans (-69%) and copepods (-66%). The decrease in abundance of Daphnia spp. was especially dramatic in Canadian waters. The decline in the southeastern region was significant for all three major groups of zooplankton, whereas in the northwestern region the decline was significant only for rotifers. From June to August 2000, Lake St. Clair open waters were numerically dominated by Dreissena spp. veligers, with a reduced abundance of rotifers and crustaceans compared to pre-Dreissena spp. surveys. Mean nutrient concentrations were not different from the 1970s, but Secchi depth (greater) and chlorophyll a concentration (lower) were. Disproportionate reduction in rotifer abundance is consistent with hypotheses implicating direct consumption by settled Dreissena spp. Reduction of crustaceans is likely due to more complex interactions including removal of nauplii as well as resource competition for phytoplankton.

  19. Use of commercial live feeds enrichment during first feeding period of the barber goby Elacatinus figaro

    Directory of Open Access Journals (Sweden)

    Marcelo R. P. Shei

    2012-03-01

    Full Text Available t. The first feeding period is the most critical phase for the production of marine fish larvae. The utilization of n-3 HUFA enrichment on live feed has improved the results for several species during the larviculture. To evaluate the effect of n-3 HUFA enrichment on survival and growth of the barber goby Elacatinus figaro Sazima, Moura & Rosa, 1997, newly hatched larvae were divided in two experimental groups (200 larvae per group, with two replicates each. One group was fed on non-enriched rotifers Brachionus plicatilis and the other group was fed with n-3 HUFA enriched rotifers. After 14 days of experiment, survival of larvae fed n-3 HUFA enriched rotifers was three times higher (35.7 ± 3.1% than those fed non-enriched rotifers (11.1 ± 5.2 %, however this difference was not significant. Growth was faster for larvae fed n-3 HUFA enriched rotifers after the first week of life, but at the end of 14 days, it was no longer significantly different between the two groups (6.09 ± 0.62 and 5.69 ± 0.66 mm. The results of this experiment suggest that barber goby should be fed n-3 HUFA enriched rotifer in order to maximize juvenile production.

  20. Effect of dietary (n-3 highly unsaturated fatty acids on growth and survival of fat snook (Centropomus parallelus, Pisces: Centropomidae larvae during first feeding

    Directory of Open Access Journals (Sweden)

    M.E.B. Seiffert

    2001-05-01

    Full Text Available The effect of rotifers, Brachionus rotundiformis (S-type, fed three different diets: A (rotifer fed Nannochloropsis oculata, B (rotifer fed N. oculata and baker's yeast, 1:1, and C (rotifer fed N. oculata and baker's yeast, 1:1, and enriched with Selcoâ, was evaluated based on the survival, growth and swim bladder inflation rate of fat snook larvae. Rotifers of treatment A had higher levels (4.58 mg/g dry weight of eicosapentaenoic acid (EPA than B (1.81 mg/g dry weight, and similar levels (0.04 and 0.06 mg/g dry weight, respectively of docosahexaenoic acid (DHA. Rotifers of treatment C had the highest levels of EPA (13.2 mg/g dry weight and DHA (6.08 mg/g dry weight. Fat snook eggs were obtained by spawning induction with human chorionic gonadotropin. Thirty hours after hatching, 30 larvae/liter were stocked in black cylindric-conical tanks (36-liter capacity. After 14 days of culture, there were no significant differences among treatments. Mean standard length was 3.13 mm for treatment A, 3.17 mm for B, and 3.39 mm for C. Mean survival rates were very low (2.7% for treatment A, 2.3% for B, and 1.8% for C. Swim bladder inflation rates were 34.7% for treatment A, 27.1% for B, and 11.9% for C. The lack of differences in growth and survival among treatments showed that the improvement of the dietary value of rotifer may not have been sufficient to solve the problem of larval rearing. Some other factor, probably pertaining to the quality of the larvae, may have negatively influenced survival.

  1. Zooplankton assemblages in montane lakes and ponds of Mount Rainier National Park, Washington State, USA

    Science.gov (United States)

    Larson, G.L.; Hoffman, R.; McIntire, C.D.; Lienkaemper, G.; Samora, B.

    2009-01-01

    Water quality and zooplankton samples were collected during the ice-free periods between 1988 and 2005 from 103 oligotrophic montane lakes and ponds located in low forest to alpine vegetation zones in Mount Rainier National Park, Washington State, USA. Collectively, 45 rotifer and 44 crustacean taxa were identified. Most of the numerically dominant taxa appeared to have wide niche breadths. The average number of taxa per lake decreased with elevation and generally increased as maximum lake depths increased (especially for rotifers). With one exception, fish presence/absence did not explain the taxonomic compositions of crustacean zooplankton assemblages. Many rotifer species were common members of zooplankton assemblages in montane lakes and ponds in western North America, whereas the crustacean taxa were common to some areas of the west, but not others. Constraints of the environmental variables did not appear to provide strong gradients to separate the distributions of most zooplankton species. This suggests that interspecific competitive interactions and stochastic processes regulate the taxonomic structures of the zooplankton assemblages at the landscape level. Crustacean species that had broad niche breadths were associated with different rotifer taxa across the environmental gradients. Studies of zooplankton assemblages need to address both crustacean and rotifer taxa, not one or the other.

  2. The Use of the Schizonticidal Agent Quinine Sulfate to Prevent Pond Crashes for Algal-Biofuel Production.

    Science.gov (United States)

    Xu, Chunyan; Wu, Kangyan; Van Ginkel, Steve W; Igou, Thomas; Lee, Hwa Jong; Bhargava, Aditya; Johnston, Rachel; Snell, Terry; Chen, Yongsheng

    2015-11-17

    Algal biofuels are investigated as a promising alternative to petroleum fuel sources to satisfy transportation demand. Despite the high growth rate of algae, predation by rotifers, ciliates, golden algae, and other predators will cause an algae in open ponds to crash. In this study, Chlorella kessleri was used as a model alga and the freshwater rotifer, Brachionus calyciflorus, as a model predator. The goal of this study was to test the selective toxicity of the chemical, quinine sulfate (QS), on both the alga and the rotifer in order to fully inhibit the rotifer while minimizing its impact on algal growth. The QS LC50 for B. calyciflorus was 17 µM while C. kessleri growth was not inhibited at concentrations <25 µM. In co-culture, complete inhibition of rotifers was observed when the QS concentration was 7.7 µM, while algal growth was not affected. QS applications to produce 1 million gallons of biodiesel in one year are estimated to be $0.04/gallon or ~1% of Bioenergy Technologies Office's (BETO) projected cost of $5/gge (gallon gasoline equivalent). This provides algae farmers an important tool to manage grazing predators in algae mass cultures and avoid pond crashes.

  3. The influence of aquatic macrophytes on distribution and feeding habit of two Asplanchna species (A. priodonta and A. herrickii in shallow wetlands, South Korea

    Directory of Open Access Journals (Sweden)

    Jong-Yun Choi

    2014-06-01

    Full Text Available We tested the hypothesis that the spatial distribution and diet composition of Asplanchna species might be affected by the presence of aquatic macrophytes in 33 wetlands in South Korea. We estimated the densities of Asplanchna and other rotifer and crustacean, together with environmental parameters, in both vegetated and open water zones, from May to June 2011. In the present study, two species of Asplanchna, A. priodonta and A. herrickii, were observed and significantly more abundant in open water zones lacking macrophytes. In particular, the density of A. priodonta was higher than that of A. herrickii, and the density of A. priodonta was strongly positively correlated with the area of open water. In addition, gut content analysis was used to determine their dietary preferences, with the finding that there was apparent differentiation in food source utilisation between the two Asplanchna species; A. priodonta consumed some protozoa, phytoplankton, and exclusively pelagic rotifer, while A. herrickii consumed primarily Euglena. In particular, Keratella and Polyarthra were most commonly consumed by A. priodonta in open water. Macrophytes represent a suitable habitat for epiphytic rotifer but not for pelagic rotifer; this characteristic drives pelagic rotifer such as Asplanchna towards open water and may be responsible for the significant negative correlation that we observed between macrophyte and Asplanchna densities.

  4. Zooplankton from a polluted river, Mula (India, with record of Brachionus rubens (Ehrenberg, 1838 epizoic on Moina macrocopa (Straus, 1820

    Directory of Open Access Journals (Sweden)

    Vanjare, A.I.

    2010-06-01

    Full Text Available Rotifera and Cladocera are free living zooplankton elements known to dominate freshwater habitats. Few rotifersare known to be parasitic and epizoic living in association with other organisms. Zooplankton from the polluted river Mula, Pune,Maharashtra was sampled from January to November 2009. Eighteen rotifers and ten cladocerans were recorded during the study.Samples revealed rotifer Brachionus rubens (Ehrenberg, 1838 epizoic on cladoceran Moina macrocopa (Straus, 1820, theoccurrence of which coincided with lower dissolved oxygen (DO content. The rotifers Asplanchnopus multiceps (Schrank,1793, Lacinularia elliptica (Shephard, 1897 and the cladoceran Kurzia longirostris (Daday, 1898 are new records to Maharashtrastate. The present study was an attempt to monitor a polluted habitat for zooplankton fauna. Detailed studies onorganically polluted eutrophic habitats could add new insights into zooplankton diversity and behaviour.

  5. Do physicochemical variables regulate the distribution of zooplankton communities in reservoirs dominated by filter-feeding carp?

    Science.gov (United States)

    Hu, Menghong; Yang, Lili; Liu, Qigen

    2014-03-01

    The temporal and spatial distributions of zooplankton communities in the upper, middle, and lower reaches of the Xin'anjiang Reservoir, Zhejiang, China, were investigated monthly, between 2009 and 2010. Silver carp ( Hypophthalmichthys molitrix) and bighead carp ( Aristichthys nobilis) dominated the pelagic fish community of this large, deep reservoir. Cladocerans were distributed evenly throughout the reservoir. Rotifers were mainly found in the upper reaches, while copepods tended to assemble in the lower reaches. The Pearson correlation analysis and stepwise multiple regression were used to identify the major physicochemical gradients influencing community variations. Zooplankton community distributions were influenced by water temperature, dissolved oxygen, phosphorus, nitrogen, and silicon. Excess nutrients, in particular silicon, stimulated rotifer growth. Based on these findings, it is possible to use rotifer density as a bioindicator of eutrophic status in deep reservoir ecosystems.

  6. VERMICOMPOST: QUALITY ORGANIC MANURE FOR ZOOPLANKTON PRODUCTION IN AQUACULTURE

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    Dinesh Kumar

    2012-08-01

    Full Text Available Purpose of the present study was to evaluate the effect of vermicompost on water quality parameters of fish pond and zooplankton production. No significant effect on the physico-chemical properties of pond water were observed though the zooplankton population was better with significant difference in rotifers population (68.38% comparing with cow dung treated pond. Application of vermicompost as an organic manure in fish pond is not only better but also safe than the raw cow dung. This is excellent manure for nursery and rearing pond as it has a potential to produce good rotifers population.

  7. The effect of DHA/EPA ratio in live feed on the fatty acid composition, survival, growth and pigmentation of turbot larvae Scophthalmus maximus L.

    OpenAIRE

    Curé, K.; Gajardo, G.; Coutteau, P.

    1996-01-01

    A set of experiments was designed to understand the effect of standardized enrichment diets on the fatty acid composition and culture performance of turbot larvae reared using the food chain rotifers -freshly hatched Artemia nauplii- enriched Artemia . Rotifers were fed on experimental diets of similar total n-3 HUFA content (34-39 mg/g DW) but different DHA/EPA ratio (0.7, 2.6 and 5.5). DHA/EPA ratio in Artemia was manipulated by 24-h enrichment with an emulsion with either a high or low DHA...

  8. Systematics and distribution of zooplankton in Lake Victoria basin, Kenya

    OpenAIRE

    Masai, D.M.; Omondi, R.; Owili, M.

    2006-01-01

    Zooplankton samples were collected, using a 60~km nansen net, from Lake Victoria (Kenya) and adjacent water bodies with emphasis being placed on the different habitats within the ecosystems. A total of 116 species were identified, 63 rotifers, 24 cladocerans and 29 copepods. A number of these were new records for the zooplankton fauna for the country.

  9. Algal defenses, population stability and the risk of herbivore extinctions: a chemostat model and experiment

    NARCIS (Netherlands)

    van der Stap, I.; Vos, M.; Kooi, B.W.; Mulling, B.T.M.; Van Donk, E.; Mooij, W.M.

    2009-01-01

    The effects of inducible defenses and constitutive defenses on population dynamics were investigated in a freshwater plankton system with rotifers as predators and different algal strains as prey. We made predictions for these systems using a chemostat predator–prey model and focused on population s

  10. Pond Power

    Science.gov (United States)

    Bode, Claudia; Criss, Mary; Ising, Andrew; McCue, Sharon; Ralph, Shannon; Sharp, Scott; Smith, Val; Sturm, Belinda

    2014-01-01

    Every year, high school students hunch over microscopes and peer at a plethora of tiny creatures. Swimming single-celled protists and whirling multicellular rotifers often steal the show, preventing students from noticing the static algae. However, these frequently overlooked, ordinary algae are inspiring research all over the world as scientists…

  11. An Updated Zooplankton Biodiversity of Turkish Inland Waters

    Directory of Open Access Journals (Sweden)

    M. Ruşen USTAOĞLU

    2015-12-01

    Full Text Available In this study, zooplankton biodiversity in Turkish inland waters is updated by literature review. In 2004, a total of 427 taxa belong to 229 rotifers, 92 cladocerans and 106 copepods have determined in a zooplankton checklist (Ustaoğlu 2004. Between 2004 and 2011, rotifer biodiversity raised from 229 to 341 taxa in the checklist (Ustaoğlu et al. 2012. By the increasing studies on the subject in recent years and as a consequence of reviewing 263 literature from the studies; 5 new genera (Ceratotrocha, Donneria, Octotrocha, Otostephanos, Stephanoceros and 76 taxa from rotifer fauna; 1 new genus (Kurzia and 11 taxa from cladoceran fauna; 13 new genera (Calacalanus, Mecynocera, Paracalanus, Lernaea, Oithona, Echinocamptus, Maraenobiotus, Leptocaris, Harpacticus, Heterolaophonte, Metis, Phyllognathopu, Kinnecaris and 35 taxa from copepod fauna have been added to the zooplankton fauna. As a result, the recent checklist of inland waters zooplankton of Turkey has 661 taxa which include 417 rotifers, 103 cladocerans and 141 copepods namely.

  12. Enhanced rates of particulate organic matter remineralization by microzooplankton are diminished by added ballast minerals

    Directory of Open Access Journals (Sweden)

    F. A. C. Le Moigne

    2013-09-01

    Full Text Available To examine the potentially competing influences of microzooplankton and calcite mineral ballast on organic matter remineralization, we incubated diatoms in darkness in rolling tanks with and without added calcite minerals (coccoliths and microzooplankton (rotifers. Concentrations of particulate organic matter (POM in suspension or in aggregates, of dissolved organic matter (DOM, and of dissolved inorganic nutrients were monitored over 8 days. The presence of rotifers enhanced the remineralization of ammonium and phosphate, but not dissolved silicon, from the biogenic particulate matter, up to 40% of which became incorporated into aggregates early in the experiment. Added calcite resulted in rates of excretion of ammonium and phosphate by rotifers that were depressed by 67% and 36%, respectively, demonstrating the potential for minerals to inhibit the destruction of POM by zooplankton in the water column. Lastly, the presence of the rotifers and added calcite minerals resulted in a more rapid initial rate of aggregation, although not a greater overall amount of aggregation during the experiment.

  13. Application of an inexpensive and high-throughput genomic DNA extraction method for the molecular ecology of zooplanktonic diapausing eggs

    DEFF Research Database (Denmark)

    Montero-Pau, Javier; Gómez, Africa; Muñoz, Joaquin

    2008-01-01

    We describe the application of a simple, low-cost, and effective method of DNA extraction (hot sodium hydroxide and Tris, HotSHOT) to the diapausing propagules of continental aquatic invertebrates for its use in PCR amplification. We illustrate the use of the technique in cladocerans, rotifers...

  14. Economic feasibility of copepod production for commercial use

    DEFF Research Database (Denmark)

    Gedefaw Abate, Tenaw; Nielsen, Rasmus; Nielsen, Max;

    2015-01-01

    , Denmark, is employed. The result reveals that commercial production of copepods is economically feasible considering the existing market prices on both copepods and competing live feed items such as rotifers. The study provides valuable information for businesses who consider investing in live feed...

  15. Producción artesanal del rotífero Philodina sp. y de algas para la alimentación de post-larvas de bocachico Artisan production of rotifero and algaes for bocachico post-larva feeding

    Directory of Open Access Journals (Sweden)

    Victoria Eugenia Quintero P

    2009-01-01

    Full Text Available El cultivo de algas mixtas se realizó en el Instituto de Piscicultura Tropical de la Corporación Autónoma Regional del Valle del Cauca (Buga 25 ºC y 969 m.s.n.m. utilizando fertilizantes inorgánicos en baldes plásticos, se produjeron en promedio 386 x 10³ células/ml de cultivo. En el cultivo de Philodina en frascos de vidrio alimentado con algas y levadura, se obtuvieron 410 rotíferos/ml de cultivo. Se evaluaron tres tratamientos: rotíferos enriquecidos con aceite de pescado; rotíferos más algas (Chlorella, Scenedesmus, Pediastrum, Spyrogira y Anabaena y Artemia salina + Spirulina, usando 100 post-larvas de bocachico/acuario, alimentadas dos veces al día según biomasa sembrada. El mayor porcentaje de sobrevivencia, peso y talla se obtuvo con el alimento constituido por rotíferos enriquecidos con aceite de pescado (93 %,3.2mg, 6.86mm, seguido de rotíferos + algas (80.67 %,2 mg, 6.1mm y Artemia+ Spirulina (60.6 %,1.6mg, 6.06mm respectivamenteIn the Tropical Piscicultural Institute of the Regional Autonomous Corporation of Buga, Cauca, Valley, Colombia (25ºC temperature, 969 m a s l, a research was carried out with the objective to produce and use algaes and rotifers (living food cultures to feed bocachico post-larvas (Prochilodus reticulatus magdalenae. A complete random design with three treatments and three repetitions was established. 100 bocachico/aquarium post larva were used and fed twice a day according to sown biomass. The cultures of mixed algaes were established by using inorganic fertilizers produced in plastic pails and obtaining an average of 386 x 10³ cells/ml of culture. On the other hand, the cultures of Philodina rotifers were established in glass bottles and feeding them with algaes and yeast. An average of 410 rotifers/ml of culturing was obtained . To evaluate the highest rate of survival, growing and weight of bocachico post-larvas, three kind of food were used: Rotifers enriched with fish oil; rotifers plus

  16. Joint inhibition of TOR and JNK pathways interacts to extend the lifespan of Brachionus manjavacas (Rotifera).

    Science.gov (United States)

    Snell, Terry W; Johnston, Rachel K; Rabeneck, Brett; Zipperer, Cody; Teat, Stephanie

    2014-04-01

    The TOR kinase pathway is central in modulating aging in a variety of animal models. The target of rapamycin (TOR) integrates a complex network of signals from growth conditions, nutrient availability, energy status, and physiological stresses and matches an organism's growth rate to the resource environment. Important remaining problems are the identification of the pathways that interact with TOR and their characterization as additive or synergistic. One of the most versatile stress sensors in metazoans is the Jun-N-terminal kinase (JNK) signaling pathway. JNK is an evolutionarily conserved stress-activated protein kinase that is induced by a range of stressors, including UV irradiation, reactive oxygen species, DNA damage, heat, and bacterial antigens. JNK is thought to interact with the TOR pathway, but its effects on TOR are poorly understood. We used the rotifer Brachionus manjavacas as a model animal to probe the regulation of TOR and JNK pathways and explore their interaction. The effect of various chemical inhibitors was examined in life table and stressor challenge experiments. A survey of 12 inhibitors revealed two, rapamycin and JNK inhibitor, that significantly extended lifespan of B. manjavacas. At 1 μM concentration, exposure to rapamycin or JNK inhibitor extended mean rotifer lifespan by 35% and maximum lifespan by 37%. Exposure to both rapamycin and JNK inhibitor simultaneously extended mean rotifer lifespan by 65% more than either alone. Exposure to a combination of rapamycin and JNK inhibitors conveyed greater protection to starvation, UV and osmotic stress than either inhibitor alone. RNAi knockdown of TOR and JNK gene expression was investigated for its ability to extend rotifer lifespan. RNAi knockdown of the TOR gene resulted in 29% extension of the mean lifespan compared to control and knockdown of the JNK gene resulted in 51% mean lifespan extension. In addition to the lifespan, we quantified mitochondria activity using the fluorescent

  17. The culture of sand goby, Oxyeleotris marmoratus II: Gastric emptying times and feed requirements of larvae

    Directory of Open Access Journals (Sweden)

    Uraiwan Chamnanwech

    2003-05-01

    Full Text Available Time of digestion experiments were carried out in a 15-liter rearing glass aquaria (water volume 10 liters containing 1,500 larvae. The larvae were fed with sufficient rotifer, Artemia or Moina and then transferred to another rearing glass aquarium without food. Samples of 20 larvae were checked at 10-minute intervals until no food remained in the larval digestive tract. It was found that the time required to empty the larval digestive tract with rotifer, Artemia or Moina was as follows. Larvae 3-18 days old fed with rotifertook 130-180 minutes to empty the digestive tract while larvae 21-27 days old fed with rotifer and Artemia took 110-120 minutes and larvae 30-45 days old fed with Moina took 80-100 minutes at water temperature of 25-29ºC. Time consumed to empty the gut content tended to decrease as larval age increased. Experiments to determined the time and amount of prey required to get satiation were carried out in a 15-liter rearing glass aquaria (water volume 10 liters containing 1,500 larvae. The larvae were fed with rotifer, Artemia or Moina after starvation of 24 hr. Samples of 20 larvae were checked at 10- inutes intervals after the start of feeding until 3 hr. It was found the time required to fill the larval digestive tract with rotifer, Artemia or Moina for 3-18 days old larvae was 80-110 minutes and amount of rotifer to get satiation was 4.8- 26 ind/larvae. For 21-27 day-old larvae the corresponding time was 60-80 minutes and was 28.5-31.6 ind/ larvae. For 30-45 day-old larvae the time was 40-60 minutes and amount of Moina to get satiation was 34.6- 52.4 ind/larvae at water temperature of 25-29ºC. The time required to fill the larval gut, tends to decrease with larval age but the amount of prey required to fill the larval gut, tends to increase with larval age. Experiments to determined the amount of food uptake in a day were done in a 15-liter rearing glass aquaria (water volume 10 liters containing 500 larvae, and 10 ind

  18. Heated relations: temperature-mediated shifts in consumption across trophic levels.

    Science.gov (United States)

    Seifert, Linda I; de Castro, Francisco; Marquart, Arnim; Gaedke, Ursula; Weithoff, Guntram; Vos, Matthijs

    2014-01-01

    A rise in temperature will intensify the feeding links involving ectotherms in food webs. However, it is unclear how the effects will quantitatively differ between the plant-herbivore and herbivore-carnivore interface. To test how warming could differentially affect rates of herbivory and carnivory, we studied trophic interaction strength in a food chain comprised of green algae, herbivorous rotifers and carnivorous rotifers at 10, 15, 20 and 25°C. We found significant warming-induced changes in feeding by both herbivorous and carnivorous rotifers, but these responses occurred at different parts of the entire temperature gradient. The strongest response of the per capita herbivore's ingestion rate occurred due to an increase in temperature from 15 to 20°C (1.9 fold: from 834 to 1611 algal cells per h(-1)) and of the per capita carnivore's ingestion rate from 20 to 25°C (1.6 fold: from 1.5 to 2.5 prey h(-1)). Handling time, an important component of a consumer's functional response, significantly decreased from 15 to 20°C in herbivorous rotifers. In contrast, it decreased from 20 to 25°C in carnivorous rotifers. Attack rates significantly and strongly increased from 10 to 25°C in the herbivorous animals, but not at all in the carnivores. Our results exemplify how the relative forces of top-down control exerted by herbivores and carnivores may strongly shift under global warming. But warming, and its magnitude, are not the only issue: If our results would prove to be representative, shifts in ectotherm interactions will quantitatively differ when a 5°C increase starts out from a low, intermediate or high initial temperature. This would imply that warming could have different effects on the relative forces of carnivory and herbivory in habitats differing in average temperature, as would exist at different altitudes and latitudes. PMID:24797506

  19. EST based phylogenomics of Syndermata questions monophyly of Eurotatoria

    Directory of Open Access Journals (Sweden)

    Bucher Gregor

    2008-12-01

    Full Text Available Abstract Background The metazoan taxon Syndermata comprising Rotifera (in the classical sense of Monogononta+Bdelloidea+Seisonidea and Acanthocephala has raised several hypotheses connected to the phylogeny of these animal groups and the included subtaxa. While the monophyletic origin of Syndermata and Acanthocephala is well established based on morphological and molecular data, the phylogenetic position of Syndermata within Spiralia, the monophyletic origin of Monogononta, Bdelloidea, and Seisonidea and the acanthocephalan sister group are still a matter of debate. The comparison of the alternative hypotheses suggests that testing the phylogenetic validity of Eurotatoria (Monogononta+Bdelloidea is the key to unravel the phylogenetic relations within Syndermata. The syndermatan phylogeny in turn is a prerequisite for reconstructing the evolution of the acanthocephalan endoparasitism. Results Here we present our results from a phylogenomic approach studying i the phylogenetic position of Syndermata within Spiralia, ii the monophyletic origin of monogononts and bdelloids and iii the phylogenetic relations of the latter two taxa to acanthocephalans. For this analysis we have generated EST libraries of Pomphorhynchus laevis, Echinorhynchus truttae (Acanthocephala and Brachionus plicatilis (Monogononta. By extending these data with database entries of B. plicatilis, Philodina roseola (Bdelloidea and 25 additional metazoan species, we conducted phylogenetic reconstructions based on 79 ribosomal proteins using maximum likelihood and bayesian approaches. Our findings suggest that the phylogenetic position of Syndermata within Spiralia is close to Platyhelminthes, that Eurotatoria are not monophyletic and that bdelloids are more closely related to acanthocephalans than monogononts. Conclusion Mapping morphological character evolution onto molecular phylogeny suggests the (partial or complete reduction of the corona and the emergence of a retractable

  20. Disentangling the effects of water chemistry and substratum structure on moss-dwelling unicellular and multicellular micro-organisms in spring-fens

    Directory of Open Access Journals (Sweden)

    Michal HORSÁK

    2011-09-01

    Full Text Available Water chemistry is known to be one of the most important factors controlling species composition of many macro-organisms in wetlands. It is unclear to what extent micro-organisms respond to water chemistry as compared to chemistry-mediated substratum structure. We explored how the assemblages of different groups of micro-organisms in bryophyte tufts of spring-fens were determined by water chemistry and substratum structure. The aim was to compare unicellular autotrophic diatoms, unicellular heterotrophic testate amoebae and multicellular heterotrophic monogonont rotifers. Assemblages of all three groups showed a strong compositional gradient correlated with water pH and conductivity, calcium concentration and dominance of Sphagnum. While a second strong gradient in species composition of diatoms and testate amoebae was explained by factors such as substratum structure and water content, that of rotifers remained unexplained. Unlike the other two groups, testate amoeba assemblages were significantly determined by phosphates. Nitrates and iron were important species composition determinants for diatoms. Rotifers differed from the other groups in that they did not respond significantly to silica, iron or nutrients. When variation caused by substratum characteristics and water chemistry were partitioned out, testate amoebae were controlled more by substratum, while rotifers and diatoms were controlled more by water chemistry. Variation explained by individual effects of substratum or water chemistry, as compared to shared effects, was much lower for rotifers than for testate amoebae and diatoms. Our results show that, in semi-terrestrial ecosystems, pH and calcium concentrations are generally the main drivers of variation in species composition of unicellular and multicellular microorganisms, mirroring well described patterns for macro-organisms, providing support for general ecological hypotheses. Other water chemistry variables differed between

  1. The culture of sand goby, Oxyeleotris marmoratus I: Feed and feeding scheme of larvae and juveniles

    Directory of Open Access Journals (Sweden)

    Uraiwan Chamnanwech

    2003-05-01

    Full Text Available Natural spawning of sand goby was carried out in earthen ponds and eggs were then collected. Fertilized eggs were incubated in a glass aquaria for hatching. The feed and feeding scheme experiments were done in the 500 liters (water volume 300 liters rearing tanks containing 1,000-1,500 of two-day old larvae (stage at first feeding. It was found that the larvae 3-18 days old (average total length 0.31-0.41 cm preferably fed only on rotifer while the 21-27 day-old larvae (average total length 0.44-0.65 cm fed on rotifer and Artemia, and the 30-45 day- old larvae (average total length 0.69-2.15 cm fed only on Moina.

  2. Nutritional enrichment of larval fish feed with thraustochytrid producing polyunsaturated fatty acids and xanthophylls.

    Science.gov (United States)

    Yamasaki, Takashi; Aki, Tsunehiro; Mori, Yuhsuke; Yamamoto, Takeki; Shinozaki, Masami; Kawamoto, Seiji; Ono, Kazuhisa

    2007-09-01

    In marine aquaculture, rotifers and Artemia nauplii employed as larval fish feed are often nutritionally enriched with forage such as yeast and algal cells supplemented with polyunsaturated fatty acids and xanthophylls, which are required for normal growth and a high survival ratio of fish larvae. To reduce the enrichment steps, we propose here the use of a marine thraustochytrid strain, Schizochytrium sp. KH105, producing docosahexaenoic acid, docosapentaenoic acid, canthaxanthin, and astaxanthin. The KH105 cells prepared by cultivation under optimized conditions were successfully incorporated by rotifers and Artemia nauplii. The contents of docosahexaenoic acid surpassed the levels required in feed for fish larvae, and the enriched Artemia showed an increased body length. The results demonstrate that we have developed an improved method of increasing the dietary value of larval fish feed. PMID:17964484

  3. Influence of dispersants on trophic transfer of petroleum hydrocarbons in a marine food chain

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, M. F.; Schwartz, G. J. B.; Singaram, S.; Tjeerdema, R. S. [California Univ., Santa Cruz, CA (United States). Dept. of Chemistry; Mielbrecht, E. E. [California Univ., Santa Cruz, CA (United States). Inst. of Marine Sciences; Sowby, M. L. [California State Dept. of Fish and Game, Sacramento, CA (United States)

    1997-10-01

    Experiments were conducted to determine the impact of dispersing agents on petroleum hydrocarbons (PH) bioavailability and trophic transfer in primary levels of a marine food chain. Uptake, bioaccumulation and metabolic transformation of a model PH, ({sup 1}4C)naphthalene, were measured and compared with Prudhoe Bay Crude Oil (PBCO) dispersed with Corexit 9527, and undispersed preparations of PBCO. The model food chain consisted of a primary algae producer and a primary rotifer consumer. Results showed that uptake of naphthalene increased significantly in the presence of a dispersant in algae. A significant increase in uptake was also recorded in rotifers via trophic transfer. Trophic transfer played a significant, sometimes even dominant, role in uptake and bioaccumulation. 27 refs., 6 figs.

  4. The Zooplankton Fauna of Kemer Dam Lake (Aydın-Turkey

    Directory of Open Access Journals (Sweden)

    Aslı TUNA

    2016-08-01

    Full Text Available In the present study the zooplankton fauna of Kemer Dam Lake (Aydın was investigated during December 2004 and November 2005. Total 24 taxa (14 taxa from rotifers, 8 taxa from cladocerans, and 2 taxa from copepods were identified in Kemer Dam Lake. Ascomorpha ovalis, Asplanchna priodonta, Collotheca pelagica, Hexarthra fennica, Keratella cochlearis, Keratella quadrata, Lecane luna, Lecane lunaris, Notholca squamula, Plationus patulus, Polyarthra dolichoptera, Polyarthra vulgaris, Synchaeta oblonga, Trichocerca similis from the rotifer species; Alona quadrangularis, Bosmina longirostris, Ceriodaphnia quadrangula, Coronatella rectangula, Daphnia cucullata, Diaphanosoma lacustris, Disparalona rostrata, Moina micrura from the Cladocera species; and Acanthodiaptomus denticornis, Cyclops abyssorum from the Copepoda species are new records for Kemer Dam lake. The average total zooplankton abundance ranged between 8706 - 124869 ind/m3 (December and April, respectively.

  5. Ecological factors affecting the distribution of the zooplankton community in the Tigris River at Baghdad region, Iraq

    OpenAIRE

    Shayma Abdulwahab; Adel M. Rabee

    2015-01-01

    Biodiversity of zooplankton in the Tigris River running in Baghdad City, central Iraq, was investigated. Fourteen physical and chemical parameters, were analyzed, these parameters include water and air temperature, pH, EC, turbidity, TDS, DO, BOD5, total hardness, Ca+2, Mg+2, chloride, nitrate and reactive phosphate. Most of these values were within of the Iraqi and international standard limits. In all, 106 taxonomy units of zooplankton were identified, including 65 taxa belonging to rotifer...

  6. Effects of dietary vitamin C on fish and crustacean larvae

    OpenAIRE

    Merchie, G.; Lavens, P.; Sorgeloos, P.

    1995-01-01

    In order to assess the dietary needs for ascorbic acid (AA) at startfeeding, the AA content in the various live diets currently applied in aquaculture (algae, rotifers, Artemia ) was studied. Application of boosting techniques using ascorbyl palmitate (AP) as the vitamin C source enabled the transfer of elevated levels of bioactive vitamin C (up to 2500µg AA.g DW-1) via the live food chain into larvae of fish (Clarias gariepinus, Dicentrarchus labrax, Scophthalmus maximus), shrimp (Pennaeus v...

  7. Optimization of dietary vitamin C in fish and crustacean larvae: a review

    OpenAIRE

    Merchie, G.; Lavens, P.; Sorgeloos, P.

    1997-01-01

    HPLC techniques were adapted and standardized for quantification of ascorbic acid (AA) and its derivates in both diets and target organisms. To assess the dietary needs for AA at start of exogenous feeding, the AA content in the various live diets currently used in aquaculture (algae, rotifers, Artemia ) was analyzed. Application of techniques for boosting vitamin C using ascorbyl palmitate as the source enabled the transfer of elevated levels (up to 2,500 µg AA/g DW) of bioactive vitamin C. ...

  8. First feeding of Eugerres brasilianus (Carapeva larvae with Acartia tonsa (Copepod nauplii increases survival and resistance to acute stress

    Directory of Open Access Journals (Sweden)

    Wanessa de Melo Costa

    2016-01-01

    Full Text Available The rotifer Brachionus sp. is commonly used for larval feeding in marine fish hatcheries. The aim of this study was to evaluate whether the inclusion of Acartia tonsa nauplii in the initial diet of carapeva larvae improves their survival, growth and resistance to stress when compared to the regimen containing only rotifers. Adult copepods were collected in the wild and cultured with the microalgae Chaetoceros muelleri, Isochrysis galbana and Nannochloropsis oculata to obtain nauplii. Carapeva larvae were grown for 15 days using four treatments and three replicates: 1 Brachionus plicatilis rotifers (10 to 15/mL; 2 A. tonsa nauplii (0.25 to 0.5/mL; 3 Brachionus plicatilis rotifers (5 to 7.5/mL + A. tonsa nauplii (0.12 to 0.25/mL, and 4 no supply of live feed. After 15 days, the carapeva larvae were subjected to stress by exposure to air for 10 seconds and then returned to the source tank to evaluate survival after 24 h. Survival and stress resistance were higher in carapeva larvae fed B. plicatilis + A. tonsa nauplii (P<0.05, 20.9 ± 11.2% and 88.9%, respectively. These results confirm the positive effect of the inclusion of copepod nauplii in the diet of fish larvae. However, more research is needed to validate these results.

  9. The zooplankton biodiversity of some freshwater environments in Parnaíba basin (Piauí, Northeastern Brazil).

    Science.gov (United States)

    Paranhos, J D N; Almeida, V L S; Silva Filho, J P; Paranaguá, M N; Melo, M; Neumann-Leitão, S

    2013-02-01

    The plankton fauna of the state of Piauí, Northeastern Brazil, especially in the Parnaíba basin, is still poorly known; the results of most studies of the subject have not been published and can only be found in grey literature (unpublished scientific works), such as course completion work and consulting reports. Thus, this paper presents data from samples taken recently from different water bodies in Piauí and represents the second study to be published on the region's zooplankton since the pioneering work of Spandl (1926). A total of 38 species were recorded, including 23 new occurrences of rotifers, 10 of cladocerans and 2 of copepods for the state of Piauí. The greatest richness was observed for the rotifers, of which the genus Brachionus must be highlighted, especially at the Joana reservoir. Among the crustaceans, the greatest richness was observed at the Bezerra reservoir, where cladocerans of the genus Bosmina were prominent. The rotifers Brachionus havanaensis Rousselet, 1911 and Filinia longiseta (Ehrenberg, 1834); the cladocerans Diaphanosoma spinulosum Herbst, 1967 and Moina micrura Kurz, 1874; and the copepods Notodiaptomus cearensis Wright, 1936 and Thermocyclops decipiens Kiefer, 1927 occurred in all or in most environments in which the respective groups were studied. The results presented here expand the taxonomic list of zooplankton for the state of Piauí, including a total fauna of 30 species of rotifers, 15 of cladocerans and 3 of copepods. The zooplankton richness was considered low in the studied reservoirs compared to other freshwater ecosystems from Northeastern Brazil; however, the few studies developed in the Parnaíba basin suggest that the diversity for these organisms should be higher. PMID:23644795

  10. Grazing by meso- and microzooplankton on phytoplankton in the upper reaches of the Schelde estuary (Belgium/The Netherlands)

    Science.gov (United States)

    Lionard, M.; Azémar, F.; Boulêtreau, S.; Muylaert, K.; Tackx, M.; Vyverman, W.

    2005-09-01

    In contrast with the marine reaches of estuaries, few studies have dealt with zooplankton grazing on phytoplankton in the upper estuarine reaches, where freshwater zooplankton species tend to dominate the zooplankton community. In spring and early summer 2003, grazing by micro- and mesozooplankton on phytoplankton was investigated at three sites in the upper Schelde estuary. Grazing by mesozooplankton was evaluated by monitoring growth of phytoplankton in 200 μm filtered water in the presence or absence of mesozooplankton. In different experiments, the grazing impact was tested of the calanoïd copepod Eurytemora affinis, the cyclopoid copepods Acanthocyclops robustus and Cyclops vicinus and the cladocera Chydorus sphaericus, Moina affinis and Daphnia magna/ pulex. No significant grazing impact of mesozooplankton in any experiment was found despite the fact that mesozooplankton densities used in the experiments (20 or 40 ind. l -1) were higher than densities in the field (0.1-6.9 ind. l -1). Grazing by microzooplankton was evaluated by comparing growth of phytoplankton in 30 and 200 μm filtered water. Microzooplankton in the 30-200 μm size range included mainly rotifers of the genera Brachionus, Trichocerca and Synchaeta, which were present from 191 to 1777 ind. l -1. Microzooplankton had a significant grazing impact in five out of six experiments. They had a community grazing rate of 0.41-1.83 day -1 and grazed up to 84% of initial phytoplankton standing stock per day. Rotifer clearance rates estimated from microzooplankton community grazing rates and rotifer abundances varied from 8.3 to 41.7 μl ind. -1 h -1. CHEMTAX analysis of accessory pigment data revealed a similar phytoplankton community composition after incubation with and without microzooplankton, indicating non-selective feeding by rotifers on phytoplankton.

  11. Spatial and temporal habitat partitioning by zooplankton in the Bornholm Basin (central Baltic Sea)

    DEFF Research Database (Denmark)

    Schultz, J.; Peck, M.A.; Barz, K.;

    2012-01-01

    taxa (Bosmina coregoni maritima, Acartia spp., Pseudocalanus spp., Temora longicornis, Synchaeta spp.) contributed >10% to the zooplankton community composition. The appearance of cladocerans was mainly correlated with the phenology of thermocline development in the spring. The cladoceran B. coregoni...... maritima was a dominant member of this community during the warmest periods, preferring the surface waters above the thermocline. Copepods exhibited distinct, ontogenetic and seasonal changes in their distribution. The rotifers (Synchaeta sp.) were the most abundant zooplankton in May. Based...

  12. Fecundity, growth, and survival of the angelfish Pterophyllum scalare (Perciformes: Cichlidae) under laboratory conditions

    OpenAIRE

    Armando A. Ortega-Salas; Isabel Cortés G.; Hugo Reyes-Bustamante

    2009-01-01

    The freshwater angelfishes (Pterophyllum) are South American cichlids that have become very popular among aquarists, yet scarce information on their culture and aquarium husbandry exists. We studied Pterophyllum scalare to analyze dietary effects on fecundity, growth, and survival of eggs and larvae during 135 days. Three diets were used: A) decapsulated cysts of Artemia, B) commercial dry fish food, and C) a mix diet of the rotifer Brachionus plicatilis and the cladoceran Daphnia magna. The ...

  13. Effect of stocking density on growth and survival of spotted sand bass Paralabrax maculatofasciatus larvae in a closed recirculating system

    OpenAIRE

    Álvarez González, Carlos; Ortiz Galindo, José Luis; Dumas, Silvie; Martínez Díaz, Sergio Francisco; Hernández Ceballos, Dora Esther; Grayeb del Alamo, Tanos; Moreno Lagorreta, Manuel; Peña Martínez, Renato; Civera Cerecedo, Roberto

    2001-01-01

    The effect on growth and survival of the initial stocking density (50, 100, 150, and 200 larvae/ L) in larval rearing of spotted sand bass was evaluated over 30 d in a closed recirculating system. Larvae were fed with rotifers, copepods, nauplii and adult Artemia, and spotted sand bass yolk-sac larvae. Water quality was monitored daily. The notochordal or standard length of sampled larvae was measured by image analysis. Specific growth rates at each density were compared by covariance analysi...

  14. Not only Cladocera: what we can learn from RRE analysis in deep lake sediment cores

    OpenAIRE

    Piscia, Roberta; Manca, Marina

    2015-01-01

    Since early palaeolimnological studies, Cladocera have been largely investigated in lakes of different typologies and from a large variety of sites. Analyses of their subfossil remains provide evidence for changes in trophodynamics, habitat and water level fluctuations and of impact of drivers such as climate change on lake ecosystem functioning. Rotifers are an important component of lacustrine food webs. They are responsible for the largest part of zooplankton diversity. Because of short de...

  15. Physicochemistry and zooplankton of two karstic sinkholes in the Yucatan Peninsula, Mexico

    OpenAIRE

    Adrian Cervantes-Martinez; Martha Gutiérrez-Aguirre

    2014-01-01

    The planktonic communities composed of rotifers and crustaceans of two tropical karstic lakes in the Yucatan Peninsula, Mexico, with similar origin but different trophic state were analyzed. Both systems, the meso-eutrophic (El Padre) and oligotrophic (Minicenote) were considered as monomictic lakes. The abundance, temporal distribution of species, richness and diversity were measured and discussed in relation to the influence of abiotic factors and the presence of a natural predator. These a...

  16. Possible applications of modern fish larviculture technology to ornamental fish production

    OpenAIRE

    Dhert, P.; Lim, L C; Candreva, P.; Van Duffel, H; Sorgeloos, P.

    1997-01-01

    There has been rapid development in the marine foodfish larviculture technology in Europe since the early eighties, especially in the flat fish, turbot and halibut, and the bass and bream species. The most significant improvements in the eighties were the introduction of light control, artificial reproduction techniques, appropriate water treatment and the use of rotifers and Artemia nauplii of specific sizes and in the late eighties and early nineties the quality enhancement of live food org...

  17. Coexisting Cyclic Parthenogens Comprise a Holocene Species Flock in Eubosmina

    OpenAIRE

    Markéta Faustová; Veronika Sacherová; H David Sheets; Jan-Erik Svensson; Taylor, Derek J.

    2010-01-01

    BACKGROUND: Mixed breeding systems with extended clonal phases and weak sexual recruitment are widespread in nature but often thought to impede the formation of discrete evolutionary clusters. Thus, cyclic parthenogens, such as cladocerans and rotifers, could be predisposed to "species problems" and a lack of discrete species. However, species flocks have been proposed for one cladoceran group, Eubosmina, where putative species are sympatric, and there is a detailed paleolimnological record i...

  18. Ingestion by Japanese Eel Anguilla japonica Larvae on Various Minute Zooplanktons

    OpenAIRE

    Wullur, Stenly; Yoshimatsu, Takao; Tanaka, Hideki; Ohtani, Masataka; Sakakura, Yoshitaka; Kim, Hee-Jin; Hagiwara, Atsushi

    2013-01-01

    We observed the feeding incidence of Japanese eel Anguilla japonica larvae of 6, 7, 8 and 14 days after hatching (DAH) using various minute zooplanktons such as rotifer (Proales similis, Synchaeta sp., Keratella sp., Brachionus rotundiformis, B. angularis) and nauplii of copepod Paracyclopina nana, and compared those results to slurry type diets (i.e., shark eggs for control) to evaluate the usability of these planktons as primary food source for the mass culture of eel larvae. Feeding incid...

  19. Biochemical composition of live feed used in cod larvae production - As good as it gets, or room for improvement?

    OpenAIRE

    Mæhre, Hanne K

    2010-01-01

    Low survival rate, slow growth and developmental abnormalities during the larval stage are challenges related to aquaculture of marine species. Several studies have shown that feeding the larvae their natural feed source, zooplankton, improves these factors significantly compared to feeding them intensive feeds like rotifers. The nutritional quality of the feed is likely to play a crucial role. Components suggested to have an impact are, for instance, the typical marine fatty acids eicosapent...

  20. The zooplankton biodiversity of some freshwater environments in Parnaíba basin (Piauí, Northeastern Brazil).

    Science.gov (United States)

    Paranhos, J D N; Almeida, V L S; Silva Filho, J P; Paranaguá, M N; Melo, M; Neumann-Leitão, S

    2013-02-01

    The plankton fauna of the state of Piauí, Northeastern Brazil, especially in the Parnaíba basin, is still poorly known; the results of most studies of the subject have not been published and can only be found in grey literature (unpublished scientific works), such as course completion work and consulting reports. Thus, this paper presents data from samples taken recently from different water bodies in Piauí and represents the second study to be published on the region's zooplankton since the pioneering work of Spandl (1926). A total of 38 species were recorded, including 23 new occurrences of rotifers, 10 of cladocerans and 2 of copepods for the state of Piauí. The greatest richness was observed for the rotifers, of which the genus Brachionus must be highlighted, especially at the Joana reservoir. Among the crustaceans, the greatest richness was observed at the Bezerra reservoir, where cladocerans of the genus Bosmina were prominent. The rotifers Brachionus havanaensis Rousselet, 1911 and Filinia longiseta (Ehrenberg, 1834); the cladocerans Diaphanosoma spinulosum Herbst, 1967 and Moina micrura Kurz, 1874; and the copepods Notodiaptomus cearensis Wright, 1936 and Thermocyclops decipiens Kiefer, 1927 occurred in all or in most environments in which the respective groups were studied. The results presented here expand the taxonomic list of zooplankton for the state of Piauí, including a total fauna of 30 species of rotifers, 15 of cladocerans and 3 of copepods. The zooplankton richness was considered low in the studied reservoirs compared to other freshwater ecosystems from Northeastern Brazil; however, the few studies developed in the Parnaíba basin suggest that the diversity for these organisms should be higher.

  1. Ecological factors affecting the distribution of the zooplankton community in the Tigris River at Baghdad region, Iraq

    Directory of Open Access Journals (Sweden)

    Shayma Abdulwahab

    2015-01-01

    Full Text Available Biodiversity of zooplankton in the Tigris River running in Baghdad City, central Iraq, was investigated. Fourteen physical and chemical parameters, were analyzed, these parameters include water and air temperature, pH, EC, turbidity, TDS, DO, BOD5, total hardness, Ca+2, Mg+2, chloride, nitrate and reactive phosphate. Most of these values were within of the Iraqi and international standard limits. In all, 106 taxonomy units of zooplankton were identified, including 65 taxa belonging to rotifers, 25 taxa to copepod and 16 taxa to Cladocera. Values of species richness index of rotifers varied from 1.051 to 12.98, for Cladocera from 1.285 to 3.41 and for copepod from 1.5 to 7.2. The Shannon–Weiner index of Rotifera varied from 0.67 to 3, 0.50–1.72 for Cladocera and from 0.91 to 2.51 for Copepoda. The uniformity index of zooplankton varied from 0.41 to 0.93 for rotifer, 0.33–1 for Cladocera and 0.36–1 for Copepoda. According to statistical analysis, temperature, EC, TDS and dissolved oxygen were observed as major factors which restrict the abundance and diversity of the zooplankton communities in the Tigris River.

  2. Diurnal Changes of Zooplankton Community Reduction Rate at Lake Outlets and Related Environmental Factors

    Science.gov (United States)

    Czerniawski, Robert; Sługocki, Łukasz

    2016-01-01

    The reduced zooplankton abundance at the outlet sections of lakes depends on the occurrence of preying fry. Therefore, light conditions can play a major role in the drift of zooplankton along river outlets. The aim of this study was to determine the influence of diurnal light conditions on the decline of zooplankton densities at lake outlets. Photosynthetically active radiation (PAR) levels were measured to determine their effect on the rate of reduced zooplankton abundance. Cladocerans and copepods showed a significantly greater reduction in abundance than rotifers and nauplii. A significant positive relationship was observed between the PAR levels and the reduced abundance of Asplanchna sp., small cladocerans, large cladocerans and Copepoda at the lake outlets. Among the rotifers, small pelagic rotifers drifted the farthest at all hours of the day. Large crustaceans, especially the large cladocerans and copepodites and adult copepods, had the lowest chance of dispersing over a wide area. Our results indicate that light conditions play an important role in the reduction of zooplankton abundance at lake outlets and have an indirect influence on the downstream food web. PMID:27392017

  3. Can microcystins affect zooplankton structure community in tropical eutrophic reservoirs?

    Science.gov (United States)

    Paes, T A S V; Costa, I A S; Silva, A P C; Eskinazi-Sant'Anna, E M

    2016-06-01

    The aim of our study was to assess whether cyanotoxins (microcystins) can affect the composition of the zooplankton community, leading to domination of microzooplankton forms (protozoans and rotifers). Temporal variations in concentrations of microcystins and zooplankton biomass were analyzed in three eutrophic reservoirs in the semi-arid northeast region of Brazil. The concentration of microcystins in water proved to be correlated with the cyanobacterial biovolume, indicating the contributions from colonial forms such as Microcystis in the production of cyanotoxins. At the community level, the total biomass of zooplankton was not correlated with the concentration of microcystin (r2 = 0.00; P > 0.001), but in a population-level analysis, the biomass of rotifers and cladocerans showed a weak positive correlation. Cyclopoid copepods, which are considered to be relatively inefficient in ingesting cyanobacteria, were negatively correlated (r2 = - 0.01; P > 0.01) with the concentration of cyanotoxins. Surprisingly, the biomass of calanoid copepods was positively correlated with the microcystin concentration (r2 = 0.44; P > 0.001). The results indicate that allelopathic control mechanisms (negative effects of microcystin on zooplankton biomass) do not seem to substantially affect the composition of mesozooplankton, which showed a constant and high biomass compared to the microzooplankton (rotifers). These results may be important to better understand the trophic interactions between zooplankton and cyanobacteria and the potential effects of allelopathic compounds on zooplankton. PMID:26959954

  4. Influence of biotic variables on invertebrate size structure and diversity in coastal wetlands of Southeastern Spain

    Science.gov (United States)

    Antón-Pardo, María; Armengol, Xavier

    2016-10-01

    Biomass and size-based estimations provide relevant information regarding ecosystem functioning and biotic interactions. Our aims were to study the effect of fish and macrophytes on the size structure of invertebrate assemblages (from rotifers to insects) in a set of coastal water bodies, estimating the biomass (total and main invertebrate groups), the biomass-size spectra (model of Pareto) and size diversity. In fishless ponds, cladoceran and ostracod biomass were higher, and they presented greater size diversity. In fish ponds, rotifer biomass presented greater proportion; while in fishless ponds, cladocerans were usually the most abundant taxa and the largest organisms. The biomass size spectra showed more irregularities in fishless ponds, due to the low densities of small taxa (rotifers and copepod juveniles) and big taxa (malacostraceans or insects). Differences is size structure and diversity were also observed between spring and summer, suggesting a higher recruitment of juveniles in spring, and thus, a higher predation pressure upon zooplankton at that moment. Macrophyte cover did not apparently influence those parameters, except for the biomass of ostracods, copepods, and insects. Therefore, predation by fish strongly affected invertebrate biomass, reflecting their selective feeding, and allowing high densities of small taxa. Predation pressure decreased size diversity, by limiting the abundance of vulnerable taxa of specific size. Seasonal changes were likely related to the spring recruitment of fish juveniles. The presence of small fish and invertebrate predator taxa among the macrophytes, restrict their role as refuges for prey invertebrates.

  5. Impact of exotic carps in the polyculture with indigenous carps: competition for food.

    Science.gov (United States)

    Siddiquee, M M R; Rahman, M F; Jahan, N; Jalal, K C A; Amin, S M N; Arshad, A

    2012-06-15

    The fingerlings of indigenous carps such as catla (Catla catla), rohu (Labeo rohita) and mrigal (Cirrhinus mrigala) with exotic carps such as silver carp (Hypophthalmichthys molitrix), bighead carp (Aristichthys nobilis) and mirror carp (Cyprinus carpio) were cultured together in a fish pond at Bangladesh Agricultural University, Mymensingh, in order to determine the food electivity, dietary overlap and food competition among indigenous major carps and exotic carps. Phytoplankton (Chlorophyceae, Cyanophyceae), zooplankton (rotifers) were the dominant groups in the cultured pond. Chlorophyceae was dominant in the diet of rohu. Chlorophyceae and rotifers were the preferred food of catla. Mrigal preferred phytoplankton than zooplankton. Rohu showed positive electivity for zooplankton. Silver carp consumed large quantity of phytoplankton and also preferred rotifers. Chlorophyceae was the dominant food group in the diet of bighead. Mirror carp also preferred plant food organisms dominated by Chlorophyceae. Bighead had positive trends towards phytoplankton. Both mrigal and mirror carp had positive electivity towards phytoplankton. The higher level of dietary overlap occurred between rohu and silver carp followed by between rohu and bighead carp and between catla and silver carp. The lowest level of dietary overlaps occurred between rohu and mirror carp. PMID:24191618

  6. Live prey enrichment and artificial microdiets for larviculture of Atlantic red porgy Pagrus pagrus

    Directory of Open Access Journals (Sweden)

    Wade O. Watanabe

    2016-05-01

    Full Text Available In the first experiment the effects of rotifer enrichment and feeding frequency on larval performance of red porgy Pagrus pagrus were studied. Larvae (2 days post-hatching = 2 dph were fed s-type rotifers (∼20 rotifers/mL enriched with one of the four different treatment media: Rotifer Diet (microalgae Nannochloropsis oculata and Tetraselmis chuii, DHA Protein Selco, Algamac 3000 (Schizochytrium sp. and Algamac + ARA (arachidonic acid. Larvae were fed daily at full ration or twice daily at half ration. Larval growth and survival (mean = 22.8% were satisfactory through 16 dph under all treatments; however, resistance to hyposaline challenge (Survival Activity Index = SAI was positively correlated (P < 0.01 with DHA concentration of rotifers, and SAI appeared highest in the Algamac + ARA treatment. In the second experiment the effects of Artemia enrichment on larval performance were compared from 18 dph through pre-metamorphosis (33 dph. Larvae were fed Artemia (0.5–3.0/mL enriched with two different media Algamac 3000 and DC DHA Selco, or unenriched Artemia (control. Both media improved DHA levels in Artemia and growth and survival (36.7–54.6% of larvae, while larvae fed unenriched Artemia showed poor growth and survival (5.2%. In the third experiment a University of North Carolina Wilmington microbound diet (MBD and two commercial microdiets (Gemma Micro and Otohime were evaluated. The MBD contained different protein sources (i.e., menhaden, squid and krill meal, soy protein concentrate and attractants. Beginning 16 dph, live feeds and microdiets were co-fed to three treatment groups of larvae: (1 Gemma, (2 MBD, and (3 Otohime. Larval performance on the UNCW-MBD was comparable to the commercial microdiets, with no significant differences in larval survival, DHA, or total n-3 PUFA content through 32 dph. Results delineate more effective rearing protocols for larviculture of Atlantic red porgy juveniles.

  7. Some aspects in early life stage of climbing perch, Anabas testudineus larvae

    Directory of Open Access Journals (Sweden)

    Ponpanom Promkaew

    2005-02-01

    volume 10 liters containing 1,000 larvae aged 1 days post-hatching (just before the mouth opened. They were fed with rotifer at a density of 10 ind/ml. Twenty larvae were collected at random from the aquarium at 2-hourly intervals, preserved in 10% buffered formalin, and then dissected to determine the presence of rotifer in the digestive tract. The digestive tracts were fixed at 32 hr of hatching at water temperatures of 27.0-30.5ºC, and measured477.63±47.80 mm in mouth height. The average number of rotifer in the digestive tract at the start of feeding was 1.50 individual/larva. A starvation experiment was carried out using a 15-liter glass aquarium (water volume 10 liters with three replications. Two hundred newly hatched larvae were kept without feeding. Larvae started to die at 216 hr and totally died within 348 hr after hatching at water temperature ranging between 27.0 and 30.5ºC. The feeding scheme experiments were done in a 15-liter glass aquarium (water volume 10 liters containing 500 of two-day old larvae (stage at first feeding. It was found that larval climbing perch aged 3- 10 days (average total length 3.02-4.97 mm consumed rotifer. The larvae of age 8-15 days (average total length 3.94-12.60 mm consumed Moina. The larvae of age 8-10 days (average total length 3.94-4.97 mmconsumed both rotifer and Moina. The larvae of age 11-day (average total length 5.51 mm consumed only Moina. The larvae of age 14-15 days (average total length 7.34-12.60 mm consumed both Moina and artificial feed. Larvae aged more than 16 days consumed only artificial feed. Determining the daily food uptake by the larvae and juveniles was done in a 15-liter glass aquarium (water volume 10 liters containing 100 larvae. The larvae consumed the living food organism i.e. rotifer or Moina depending on larval stage, with density of rotifer 100 individual/ml or with density of Moina 10 individual/ml. The amount of food intake was calculated based on changes of food density in the

  8. Synergistic toxicity of Macondo crude oil and dispersant Corexit 9500A® to the Brachionus plicatilis species complex (Rotifera)

    International Nuclear Information System (INIS)

    Using the marine rotifer Brachionus plicatilis acute toxicity tests, we estimated the toxicity of Corexit 9500A®, propylene glycol, and Macondo oil. Ratios of 1:10, 1:50 and 1:130 for Corexit 9500A®:Macondo oil mixture represent: maximum exposure concentrations, recommended ratios for deploying Corexit (1:10–1:50), 1:130 the actual dispersant:oil ratio used in the Deep Water Horizon spill. Corexit 9500A® and oil are similar in their toxicity. However, when Corexit 9500A® and oil are mixed, toxicity to B. manjavacas increases up to 52-fold. Extrapolating these results to the oil released by the Macondo well, suggests underestimation of increased toxicity from Corexit application. We found small differences in sensitivity among species of the B. plicatilis species complex, likely reflecting phylogenetic similarity. Just 2.6% of the water-accommodated fraction of oil inhibited rotifer cyst hatching by 50%, an ecologically significant result because rotifer cyst in sediments are critical resources for the recolonization of populations each Spring. - Highlights: ► We determined LC50's of Corexit 9500A®, propylene glycol, and oil to B. plicatilis. ► Corexit 9500A® and oil are equivalent in toxicity. ► When Corexit 9500A® and oil are mixed, toxicity increases 52-fold to B. plicatilis. ► Results suggest underestimation of increased toxicity due to Corexit application. ► Sensitivity differences are small among species of the B. plicatilis species complex. - Using Brachionus plicatilis acute toxicity tests we estimated Corexit 9500A® and oil toxicity. When these compounds are mixed a 52-fold increase in toxicity was observed.

  9. Water quality in Lake Xochimilco, Mexico: zooplankton indicators and Vibrio cholerae

    Directory of Open Access Journals (Sweden)

    Sarma Nandini

    2015-08-01

    Full Text Available Lake Xochimilco is a eutrophic water body in Mexico City used by the local population for aquaculture and agriculture. Water level is maintained with inputs of partially treated waste water from the Cerro de la Estrella treatment plant. In this study we analysed the water quality at two sites of Lake Xochimilco, Lake Xaltocan and the Santa Cruz Canal using various indicators such as zooplankton diversity, saprobic indices, bacterial concentrations and physico-chemical variables. Eighty litres of water was filtered from Lake Xochimilco from each site, once a month from March to October of 2012, and the rotifers, cladocerans and copepods were enumerated and identified. Physico-chemical parameters such as temperature, pH, Secchi depth, water depth, nitrogen and phosphorus and chlorophyll a concentrations, and bacterial densities were measured. During the study we recorded 33 species of rotifers, the most abundant being Brachionus angularis, B. calyciflorus and B. havanaensis.  Among the microcrustaceans the most abundant were the cladoceran Moina micrura and the copepods Acanthocyclops americanus and Arctodiaptomus dorsalis. The species diversity was around 2 bits/ind. and the saprobic index between 1.5-2.0, indicating that both sites were β meso-saprobic.  At both sites nitrogen was <1 mg/L and phosphorus ranged between 2.5-7.8 mg/L. Chlorophyll a concentrations were between 66-136 µg/L. The toxigenic (Vibrio cholerae No-O1/No-O139 and the non-toxigenic (Vibrio cholerae No-O135 strains of the bacterium were recorded, closely associated with littoral rotifers and cladocerans particularly Brachionus quadridentatus and  Alona sp. All variables indicate that these sites in Lake Xochimilco are eutrophic and highly contaminated and that the water quality needs to be improved.

  10. [Influences of water-saved and nitrogen-reduced practice on soil microbial and microfauna assemblage in paddy field].

    Science.gov (United States)

    Gui, Juan; Chen, Xiao-yun; Liu, Man-qiang; Zhuang, Xi-ping; Sun, Zhen; Hu, Feng

    2016-01-01

    The resource and environmental problems caused by excessive consumption of water and fertilizer in rice production have recently aroused widespread concern. This study investigated the effects of irrigation modes (conventional irrigation and 25% water-saved irrigation) and different N application rates (conventional high-nitrogen fertilization and 40% nitrogen-reduced fertilization) on microbial and microfauna assemblages at tillering and ripening stages in paddy field. The results showed that compared with conventional irrigation (CF), water-saved irrigation (WS) decreased the soil pH at tillering stage. Soil dissolved organic matter (dissolved organic C and N) and microbial biomass C and N were significantly affected by irrigation, nitrogen fertilizer and their interactions. WS or N-reduced fertilization (LN) decreased the contents of dissolved organic matter; WS increased microbial biomass C but decreased microbial biomass N. Nitrate was significantly higher in WS than CF, while ammonium showed reverse pattern. At tillering stage, the soil microbial biomass from bacteria, fungi, actinomy and protozoa was higher in WS than in CF, but the trend was opposite at ripening stage. There was a significant interation between irrigation and fertilization on soil rotifer numbers and microbial-feeding nematodes. At tillering stage, WS increased the numbers of rotifer and nematode, and also the proportion of bacterial-feeding nematode; LN increased the abundance of rotifer but decreased the abundance of nematode. In summary, soil microbial and microfauna assemblages showed different response to water-saved and nitrogen-reduced agricultural managements, which depended on different crop growth stages, but also the complex interactions of water and nitrogen and between biological groups in food webs. PMID:27228599

  11. Long-term survival of hydrated resting eggs from Brachionus plicatilis.

    Directory of Open Access Journals (Sweden)

    Melody S Clark

    Full Text Available BACKGROUND: Several organisms display dormancy and developmental arrest at embryonic stages. Long-term survival in the dormant form is usually associated with desiccation, orthodox plant seeds and Artemia cysts being well documented examples. Several aquatic invertebrates display dormancy during embryonic development and survive for tens or even hundreds of years in a hydrated form, raising the question of whether survival in the non-desiccated form of embryonic development depends on pathways similar to those occurring in desiccation tolerant forms. METHODOLOGY/PRINCIPAL FINDINGS: To address this question, Illumina short read sequencing was used to generate transcription profiles from the resting and amictic eggs of an aquatic invertebrate, the rotifer, Brachionus plicatilis. These two types of egg have very different life histories, with the dormant or diapausing resting eggs, the result of the sexual cycle and amictic eggs, the non-dormant products of the asexual cycle. Significant transcriptional differences were found between the two types of egg, with amictic eggs rich in genes involved in the morphological development into a juvenile rotifer. In contrast, representatives of classical "stress" proteins: a small heat shock protein, ferritin and Late Embryogenesis Abundant (LEA proteins were identified in resting eggs. More importantly however, was the identification of transcripts for messenger ribonucleoprotein particles which stabilise RNA. These inhibit translation and provide a valuable source of useful RNAs which can be rapidly activated on the exit from dormancy. Apoptotic genes were also present. Although apoptosis is inconsistent with maintenance of prolonged dormancy, an altered apoptotic pathway has been proposed for Artemia, and this may be the case with the rotifer. CONCLUSIONS: These data represent the first transcriptional profiling of molecular processes associated with dormancy in a non-desiccated form and indicate important

  12. Allometric growth and development of organs in ballan wrasse (Labrus bergylta Ascanius, 1767) larvae in relation to different live prey diets and growth rates.

    Science.gov (United States)

    Gagnat, Maren Ranheim; Wold, Per-Arvid; Bardal, Tora; Øie, Gunvor; Kjørsvik, Elin

    2016-09-15

    Small fish larvae grow allometrically, but little is known about how this growth pattern may be affected by different growth rates and early diet quality. The present study investigates how different growth rates, caused by start-feeding with copepods or rotifers the first 30 days post-hatch (dph), affect allometric growth and development of nine major organs in ballan wrasse (Labrus bergylta) larvae up to experimental end at 60 dph. Feeding with cultivated copepod nauplii led to both increased larval somatic growth and faster development and growth of organ systems than feeding with rotifers. Of the organs studied, the digestive and respiratory organs increased the most in size between 4 and 8 dph, having a daily specific growth rate (SGR) between 30 and 40% in larvae fed copepods compared with 20% or less for rotifer-fed larvae. Muscle growth was prioritised from flexion stage and onwards, with a daily SGR close to 30% between 21 and 33 dph regardless of treatment. All larvae demonstrated a positive linear correlation between larval standard length (SL) and increase in total tissue volume, and no difference in allometric growth pattern was found between the larval treatments. A change from positive allometric to isometric growth was observed at a SL close to 6.0 mm, a sign associated with the start of metamorphosis. This was also where the larvae reached postflexion stage, and was accompanied by a change in growth pattern for most of the major organ systems. The first sign of a developing hepatopancreas was, however, first observed in the largest larva (17.4 mm SL, 55 dph), indicating that the metamorphosis in ballan wrasse is a gradual process lasting from 6.0 to at least 15-17 mm SL.

  13. Effect of food type and concentration on growth and fatty acid composition of early larvae of the anchovy (Engraulis encrasicolus) reared under laboratory conditions

    KAUST Repository

    Garrido, Susana

    2012-12-01

    Experiments were conducted during the summer of 2008 and 2009 to study the growth of early post yolk-sac European anchovy (Engraulis encrasicolus, Linnaeus, 1758) larvae reared under different food regimes. The fatty acid composition was used to assess nutritional condition of the larvae. Prey items used in the experiments were Gymnodinium sanguineum, Brachionus plicatilis and nauplii of the copepods Acartia grani and Euterpina acutifrons. Food type and concentration affected the growth of the larvae. Mixed diets composed of rotifers and copepod nauplii at high concentration resulted in higher anchovy larvae growth rates in comparison with single-prey diets using either rotifers or copepod nauplii. The addition of the dinoflagellate G. sanguineum (25-50cellsml -1) to the prey offered did not enhance significantly larval growth. Highest growth rates of anchovy larvae (0.28mmd -1) were obtained using high concentrations of a mixed diet, particularly the combination of rotifers and A. grani nauplii. Fatty acid composition at hatch was similar to the composition observed in the field, but during larvae ontogeny there was a marked decrease in the contribution of polyunsaturated fatty acids such as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). Such difference reflects the high requirements of these PUFA for larvae development, and suggests that the food offered failed to fulfill the larvae nutritional requirements. The growth rates obtained in our experiments were, overall, in the lower range of those observed in natural conditions. Taking into considerations the fact that larvae in the field are expected to encounter lower prey concentrations, we discuss the reasons for such disagreement. © 2012 Elsevier B.V.

  14. [Influences of water-saved and nitrogen-reduced practice on soil microbial and microfauna assemblage in paddy field].

    Science.gov (United States)

    Gui, Juan; Chen, Xiao-yun; Liu, Man-qiang; Zhuang, Xi-ping; Sun, Zhen; Hu, Feng

    2016-01-01

    The resource and environmental problems caused by excessive consumption of water and fertilizer in rice production have recently aroused widespread concern. This study investigated the effects of irrigation modes (conventional irrigation and 25% water-saved irrigation) and different N application rates (conventional high-nitrogen fertilization and 40% nitrogen-reduced fertilization) on microbial and microfauna assemblages at tillering and ripening stages in paddy field. The results showed that compared with conventional irrigation (CF), water-saved irrigation (WS) decreased the soil pH at tillering stage. Soil dissolved organic matter (dissolved organic C and N) and microbial biomass C and N were significantly affected by irrigation, nitrogen fertilizer and their interactions. WS or N-reduced fertilization (LN) decreased the contents of dissolved organic matter; WS increased microbial biomass C but decreased microbial biomass N. Nitrate was significantly higher in WS than CF, while ammonium showed reverse pattern. At tillering stage, the soil microbial biomass from bacteria, fungi, actinomy and protozoa was higher in WS than in CF, but the trend was opposite at ripening stage. There was a significant interation between irrigation and fertilization on soil rotifer numbers and microbial-feeding nematodes. At tillering stage, WS increased the numbers of rotifer and nematode, and also the proportion of bacterial-feeding nematode; LN increased the abundance of rotifer but decreased the abundance of nematode. In summary, soil microbial and microfauna assemblages showed different response to water-saved and nitrogen-reduced agricultural managements, which depended on different crop growth stages, but also the complex interactions of water and nitrogen and between biological groups in food webs.

  15. Biodiversity increases the productivity and stability of phytoplankton communities.

    Directory of Open Access Journals (Sweden)

    Alina A Corcoran

    Full Text Available Global biodiversity losses provide an immediate impetus to elucidate the relationships between biodiversity, productivity and stability. In this study, we quantified the effects of species richness and species combination on the productivity and stability of phytoplankton communities subject to predation by a single rotifer species. We also tested one mechanism of the insurance hypothesis: whether large, slow-growing, potentially-defended cells would compensate for the loss of small, fast-growing, poorly-defended cells after predation. There were significant effects of species richness and species combination on the productivity, relative yield, and stability of phytoplankton cultures, but the relative importance of species richness and combination varied with the response variables. Species combination drove patterns of productivity, whereas species richness was more important for stability. Polycultures containing the most productive single species, Dunaliella, were consistently the most productive. Yet, the most species rich cultures were the most stable, having low temporal variability in measures of biomass. Polycultures recovered from short-term negative grazing effects, but this recovery was not due to the compensation of large, slow-growing cells for the loss of small, fast-growing cells. Instead, polyculture recovery was the result of reduced rotifer grazing rates and persisting small species within the polycultures. Therefore, although an insurance effect in polycultures was found, this effect was indirect and unrelated to grazing tolerance. We hypothesize that diverse phytoplankton assemblages interfered with efficient rotifer grazing and that this "interference effect" facilitated the recovery of the most productive species, Dunaliella. In summary, we demonstrate that both species composition and species richness are important in driving patterns of productivity and stability, respectively, and that stability in biodiverse

  16. Virus-phytoplankton adhesion: a new WSSV transmission route to zooplankton

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The pathogenicity of white spot syndrome virus (WSSV) to zooplankton species, rotifer Brachionus urceus (Linnaeus), copepod Acartia clausi (Giesbrecht) and mysid shrimp Neomysis awatschensis (Brandt), was estimated by immersion challenge and virus-phytoplankton adhesion route to investigate a potential new transmission route of WSSV to zooplankton. WSSV succeeded in infecting these zooplankton species and nested-PCR revealed positive results for the virus-phytoplankton adhesion route, whereas WSSV cannot infect zooplankton by immersion challenge. These results indicated that virus-phytoplankton adhesion route is a successful new transmission route of WSSV to zooplankton and also implied that phytoplankton could be a carrier in WSSV transmission.

  17. ZOOPLANCTON EN LA LARVICULTURA DE PECES NEOTROPICALES

    Directory of Open Access Journals (Sweden)

    Martha Prieto G

    2008-08-01

    Full Text Available Because of the poor development of digestive system and swimming capability of young fish, larviculture of altricial neotropical fish presents for the management of the initial feeding. The feeding of the larvae must consider the size, density and quality of the prey offered. This document reviews the incidence of zooplankton in fish larvicultura, approaches the importance of larviculture in fish rearing, the importance of zooplankton as prey, and alternatives in the handling of cladocerans, copepods and rotifers for the feeding of larvae of neotropical fishes.

  18. Moderately lower temperatures greatly extend the lifespan of Brachionus manjavacas (Rotifera): Thermodynamics or gene regulation?

    Science.gov (United States)

    Johnston, Rachel K; Snell, Terry W

    2016-06-01

    Environmental temperature greatly affects lifespan in a wide variety of animals, but the exact mechanisms underlying this effect are still largely unknown. A moderate temperature decrease from 22°C to 16°C extends the lifespan of the monogonont rotifer Brachionus manjavacas by up to 163%. Thermodynamic effects on metabolism contribute to this increase in longevity, but are not the only cause. When rotifers are exposed to 16°C for four days and then transfered to 22°C, they survive until day 13 at nearly identical rates as rotifers maintained at 16°C continuously. This persistence of the higher survival for nine days after transfer to 22°C suggests that low temperature exposure alters the expression of genes that affect the rate of aging. The relative persistence of the gene regulation effect suggests that it may play an even larger role in slowing aging than the thermodynamic effects. The life extending effects of these short-term low temperature treatments are largest when the exposure happens early in the life cycle, demonstrating the importance of early development. There is no advantage to lowering the temperature below 16°C to 11° or 5°C. Rotifers exposed to 16°C also displayed increased resistance to heat, starvation, oxidative and osmotic stress. Reproductive rates at 16°C were lower than those at 22°C, but because they reproduce longer, there is no significant change in the lifetime fecundity of females. To investigate which genes contribute to these effects, the expression of specific temperature sensing genes was knocked down using RNAi. Of 12 genes tested, RNAi knockdown of four eliminated the survival enhancing effects of the four-day cold treatment: TRP7, forkhead box C, Y-box factor, and ribosomal protein S6. This demonstrates that active gene regulation is an important factor in temperature mediated life extension, and that these particular genes play an integral role in these pathways. As a thermoresponsive sensor, TRP7 may be

  19. 赤点石斑鱼人工育苗的初步研究

    Institute of Scientific and Technical Information of China (English)

    马荣和; 李加儿; 周宏团; 丁彦文; 郑建民; 邹婉虹

    1987-01-01

    The preliminary result of study on the artificial seed breeding of garrupa, Epinephelus akaara, larva obtained from the artificial propagation was report. The larva were fed with rotifers and copepods. Thirty two days later, postlarva were reared, with a survival rate of 0.8%.While the juvenile were fed with minced shrimp and fish, as well as small shrimp and fish, their survival rate was 100% After nine months of seed breeding, young fish attained the total length of 180mm on the average, and the weight was 100g.

  20. Importance et rôle du zooplancton dans une lagune tropicale, la lagune Ebrié (Côte d'Ivoire) : peuplements, biomasse, production et bilan métabolique

    OpenAIRE

    PAGANO, Marc; Saint-Jean, L.

    1991-01-01

    Le programme a été axé sur l'étude au cours de deux cycles annuels de cinq stations représentatives de l'éventail des conditions écologiques. Des analyses sur le seston permettent de caractériser l'environnement trophique. Le zooplancton est dominé par #Acartia clausi$, #Oithona brevicornis$, #Pseudodiaptomus hessei$, les rotifères et les larves de lamellibranches. En termes de biomasse les copépodes forment le groupe dominant (89%). L'importance pondérale du macroplancton dominé par les mysi...

  1. The diet of Enoplus brevis (Nematoda) in a supralittoral salt marsh of the North Sea

    Science.gov (United States)

    Hellwig-Armonies, Monika; Armonies, Werner; Lorenzen, Sievert

    1991-09-01

    The gut content of nearly 2000 specimens of Enoplus brevis was quantitatively analysed. E. brevis is an opportunistic omnivore. Main food categories found were cyanobacteria, diatoms, oligochaetes, nematodes, and rotifers. With a few exceptions, the diet of females and males was identical. Predominantly, juveniles fed on cyanobacteria and adults on animal prey. Experiments revealed that living oligochaetes are attacked and preyed upon. The quantities of the food categories eaten by Enoplus varied according to their ambient abundance, both temporarily and spatially on a small scale. At least the nematode prey was strongly selected: some species were significantly preferred and others avoided.

  2. Contributions towards a specific DHA enrichment in the live food Brachionus plicatilis and Artemia sp.

    OpenAIRE

    Dhert, Ph.; Sorgeloos, P.; Devresse, B.

    1993-01-01

    This paper reports on enrichment techniques oriented towards a specific DHA accumulation in the live prey Brachionus plicatilis and Artemia sp. The product used in these experiments (DHA7) is an experimental emulsion with a DHA/EPA ratio 6.7:1. Rotifers enriched with this pure DHA7 emulsion contained up to 69 mg/g DW DHA and a DHA/EPA ratio of 1.6. The DHA/EPA ration could be increased to a much higher level by different enrichment techniques. Dilution of the DHA7 emulsion with coconut oil pr...

  3. Outcome of EPIZONE Extension ON VER/VNN: Pathogenicity study of 10 betanodavirus strains with an in vivo challenge in European sea bass (Dicentrarchus labrax)

    DEFF Research Database (Denmark)

    Vendramin, Niccolò; Toffan, A.; Cappellozza, E.;

    2012-01-01

    , is considered the most serious viral threat affecting marine farmed species in the Mediterranean region, thus representing one of the bottlenecks for further development of aquaculture industry. Epidemiological investigations carried out in different geographical areas demonstrated that Betanodavirus can...... be detected in wild fish as well as other aquatic organisms (artemia, rotifers, molluscs and crustaceans) in addition to farmed fish. The RGNNV genotype is the most widespread in the Mediterranean region, nevertheless some strains, characterized by containing genetic material belonging to both the RGNNV...

  4. Moderately lower temperatures greatly extend the lifespan of Brachionus manjavacas (Rotifera): Thermodynamics or gene regulation?

    Science.gov (United States)

    Johnston, Rachel K; Snell, Terry W

    2016-06-01

    Environmental temperature greatly affects lifespan in a wide variety of animals, but the exact mechanisms underlying this effect are still largely unknown. A moderate temperature decrease from 22°C to 16°C extends the lifespan of the monogonont rotifer Brachionus manjavacas by up to 163%. Thermodynamic effects on metabolism contribute to this increase in longevity, but are not the only cause. When rotifers are exposed to 16°C for four days and then transfered to 22°C, they survive until day 13 at nearly identical rates as rotifers maintained at 16°C continuously. This persistence of the higher survival for nine days after transfer to 22°C suggests that low temperature exposure alters the expression of genes that affect the rate of aging. The relative persistence of the gene regulation effect suggests that it may play an even larger role in slowing aging than the thermodynamic effects. The life extending effects of these short-term low temperature treatments are largest when the exposure happens early in the life cycle, demonstrating the importance of early development. There is no advantage to lowering the temperature below 16°C to 11° or 5°C. Rotifers exposed to 16°C also displayed increased resistance to heat, starvation, oxidative and osmotic stress. Reproductive rates at 16°C were lower than those at 22°C, but because they reproduce longer, there is no significant change in the lifetime fecundity of females. To investigate which genes contribute to these effects, the expression of specific temperature sensing genes was knocked down using RNAi. Of 12 genes tested, RNAi knockdown of four eliminated the survival enhancing effects of the four-day cold treatment: TRP7, forkhead box C, Y-box factor, and ribosomal protein S6. This demonstrates that active gene regulation is an important factor in temperature mediated life extension, and that these particular genes play an integral role in these pathways. As a thermoresponsive sensor, TRP7 may be

  5. Studies on the zooplankton of the deep subalpine Lake Garda.

    Directory of Open Access Journals (Sweden)

    Luigi NASELLI-FLORES

    1999-02-01

    Full Text Available The specific composition and seasonal dynamics of the zooplankton of Lake Garda have been studied through monthly surveys in two annual cycles (December 1994-November 1995 and January-December 1997. The assemblage is largely dominated by Copipodiaptomus steueri, a typical calanoid presently identified in deep (Garda, Iseo and shallow lakes of NE Italy and in the hinterland of the central Adriatic region (Dalmatia and Marche Region. Cladocerans and the smaller rotifers represent a significant component of the zooplankton from spring to autumn. A re-examination of the results obtained in previous studies does not seem to demonstrate substantial shifts in the composition of the dominant species. The only documentable and consolidated differences are constituted by the disappearance of Sida crystallina since the '50s and the appearance of new rotifers since the '70s and the '80s. It is stressed that, owing to the fragmentation of the available studies and the use of different methodologies, the qualitative and quantitative modifications of the zooplankton should be interpreted with special caution, requiring further in-depth and continuous monitoring for the meaning they could have as possible signs of modifications of the trophic structure of the lake. However, the results of the comparison of the different investigations do not seem to contrast with the substantial stability of the oligo-mesotrophic character of the lake formally documented since the '70s.

  6. Determinants of community structure of zooplankton in heavily polluted river ecosystems

    Science.gov (United States)

    Xiong, Wei; Li, Jie; Chen, Yiyong; Shan, Baoqing; Wang, Weimin; Zhan, Aibin

    2016-02-01

    River ecosystems are among the most affected habitats globally by human activities, such as the release of chemical pollutants. However, it remains largely unknown how and to what extent many communities such as zooplankton are affected by these environmental stressors in river ecosystems. Here, we aim to determine major factors responsible for shaping community structure of zooplankton in heavily polluted river ecosystems. Specially, we use rotifers in the Haihe River Basin (HRB) in North China as a case study to test the hypothesis that species sorting (i.e. species are “filtered” by environmental factors and occur at environmental suitable sites) plays a key role in determining community structure at the basin level. Based on an analysis of 94 sites across the plain region of HRB, we found evidence that both local and regional factors could affect rotifer community structure. Interestingly, further analyses indicated that local factors played a more important role in determining community structure. Thus, our results support the species sorting hypothesis in highly polluted rivers, suggesting that local environmental constraints, such as environmental pollution caused by human activities, can be stronger than dispersal limitation caused by regional factors to shape local community structure of zooplankton at the basin level.

  7. Ingestion of Brachionus plicatilis under different microalgae conditions

    Science.gov (United States)

    Zhou, Wenli; Tang, Xuexi; Qiao, Xiuting; Wang, You; Wang, Renjun; Feng, Lei

    2009-09-01

    The effects of four microalgae, Chlorella vulgaris, Platymonas helgolandicavar, Isochrysis galbana, and Nitzschia closterium on the grazing and filtering rates of the marine rotifer, Brachionus plicatilis, were evaluated under laboratory conditions. The grazing rates in separate cultures of the four microalga were as follows: C. vulgaris > P. helgolandicavar > I. galbana > N. closterium. However, the filtering rates occurred in the following order: P. helgolandicavar > N. closterium > C. vulgaris > I. galbana. A mixed diets experiment revealed that P. helgolandicavar was the preferred diet of B. plicatilis. In addition, the grazing rate of B. plicatilis increased gradually as the density of the microalgae increased, until concentrations of 2.5×106 cells mL-1 for C. vulgaris and 1.5×106 cells mL-1 for I. galbana were obtained. Furthermore, the filtering rate increased slightly when the density of the microalgae was low, after which it declined as the microalgal density increased. The grazing rates of B. plicatilis were as follows during the different growth phases: stationary phase > exponential phase > lag phase > decline phase. Additionally, the filtering rates during the growth phases were: exponential phase > lag phase > stationary phase > decline phase. The results of this study provide foundational information that can be used to explore the optimal culture conditions for rotifers and to promote the development of aquaculture.

  8. Ingestion of Brachionus plicatilis under different microalgae conditions

    Institute of Scientific and Technical Information of China (English)

    ZHOU Wenli; TANG Xuexi; QIAO Xiuying; WANG You; WANG Renjun; FENG Lei

    2009-01-01

    The effects of four microalgae, Chlorella vulgaris, Platymonas helgolandicavar, Isochrysis galbana, and Nitzschia closterium on the grazing and filtering rates of the marine rotifer, Brachionus plicatilis, were evaluated under laboratory conditions. The grazing rates in separate cultures of the four microalga were as follows: C. vulgaris > P. helgolandicavar > I. galbana > N. closterium. However, the filtering rates occurred in the following order: P. helgolandicavar > N. closterium > C. vulgaris > I. galbana. A mixed diets experiment revealed that P. helgolandicavar was the preferred diet of B. plicatilis. In addition, the grazing rate of B. plicatilis increased gradually as the density of the microalgae increased, until concentrations of 2.5×106 cells mL-1 for C. vulgaris and 1.5×106 cells mL-1 for I. galbana were obtained. Furthermore, the filtering rate increased slightly when the density of the microalgae was low, after which it declined as the microalgal density increased. The grazing rates of B. plicatilis were as follows during the different growth phases: stationary phase > exponential phase > lag phase > decline phase. Additionally, the filtering rates during the growth phases were: exponential phase > lag phase > stationary phase > decline phase. The results of this study provide foundational information that can be used to explore the optimal culture conditions for rotifers and to promote the development of aquaculture.

  9. Seasonal variations of species composition and abundance of zooplankton in Ehoma Lake, a floodplain lake in Nigeria.

    Science.gov (United States)

    Okogwu, Okechukwu I

    2010-03-01

    Ehoma Lake is among the important breeding sites of the major fishes in the Mid-Cross River, Nigeria. The juveniles of these fishes are solely dependent on zooplankton, which has not been studied previously. I studied monthly the lake's physico-chemical variables and zooplankton composition in three stations (littoral, sub-littoral and pelagic) from March 2005 to August 2006. Sixty-seven zooplankton species (42 rotifers, 19 cladocerans and 6 copepods) were identified. Daphnia obtusa Kurz, Keratella valga Ehrenberg, Keratella ticinensis Callerrio, Keratella hiemalis Carlin, Brachionus dimidiatus Bryce and Lecane candida Hauer and Murray are new records for Nigeria The dominant zooplankters were Diaphanosoma excisum Kurz and Moina micrura Kurz. There was an inverse relationship between species richness and abundance. Richness was highest in the dry season while peak zooplankton abundance was recorded in the rainy season. Zooplankton abundance and species richness decreased progressively from the littoral to the pelagic station while the Shannon-Weaver diversity index varied from 0.68 to 1.28 without a clear seasonal trend. There is a succession pattern: rotifers that are dominant in the dry season are replaced by cladocerans in the rainy season. This succession was greatly influenced by seasonal flooding of the lake. As no previous information on the zooplankton of the lake is available, this study provides baseline data on the lake's zooplankton. PMID:20411715

  10. Impact of single and repeated applications of the insecticide chlorpyrifos on tropical freshwater plankton communities.

    Science.gov (United States)

    Daam, Michiel A; Van den Brink, Paul J; Nogueira, António J A

    2008-11-01

    This paper describes the effects of a single and a repeated application of the organophosphorus insecticide chlorpyrifos on zooplankton and phytoplankton communities in outdoor microcosms in Thailand. Treatment levels of 1 microg L(-1) were applied once or twice with a 2-week interval. Both treatments led to a significant decrease in cladocerans followed by an increase in rotifers, although the extent by which species were affected was different. Ceriodaphnia cornuta was the most responding cladoceran after the first treatment, while Moina micrura responded most to the second. This is explained by differences in the growth phase of M. micrura at the time of application and an increase in Microcystis abundance over the course of the experiment. Several phytoplankton taxa either increased or decreased as a result of the chlorpyrifos-induced changes in zooplankton communities. Even though chlorpyrifos disappeared fast from the water column, effects on plankton communities persisted till the end of the experiment (42 days) when the insecticide concentrations had dropped below the detection limit. This was presumably due to the increasing population trend of Microcystis, favouring rotifers over cladocerans. PMID:18498053

  11. The Selective Use of Hypochlorite to Prevent Pond Crashes for Algae-Biofuel Production.

    Science.gov (United States)

    Park, Sichoon; Van Ginkel, Steven W; Pradeep, Priya; Igou, Thomas; Yi, Christine; Snell, Terry; Chen, Yongsheng

    2016-01-01

    Although algae-biofuels have many advantages including high areal productivity, algae can be preyed upon by amoebas, protozoans, ciliates, and rotifers, particularly in open pond systems. Thus, these higher organisms need to be controlled. In this study, Chlorella kessleri was used as the algal culture and Brachionus calyciflorus as the source of predation. The effect of sodium hypochlorite (bleach) was tested with the goal of totally inhibiting the rotifer while causing minor inhibition to the alga. The 24-hr LC(50) for B. calyciflorus in spring water was 0.198 mg Cl/L while the 24-hr LC(50) for C. kessleri was 0.321 mg Cl/L. However, chlorine dissipates rapidly as the algae serves as reductant. Results showed a chlorine dosage between 0.45 to 0.6 mg Cl/L and a dosing interval of two hours created the necessary chlorine concentrations to inhibit predation while letting the algae grow; thus giving algae farmers a tool to prevent pond crashes.

  12. Effects of polycyclic aromatic hydrocarbons (PAHs) on an aquatic ecosystem: acute toxicity and community-level toxic impact tests of benzo[a]pyrene using lake zooplankton community.

    Science.gov (United States)

    Ikenaka, Yoshinori; Sakamoto, Masaki; Nagata, Takamaru; Takahashi, Hirokazu; Miyabara, Yuichi; Hanazato, Takayuki; Ishizuka, Mayumi; Isobe, Tomohiko; Kim, Jun-Woo; Chang, Kwang-Hyeon

    2013-02-01

    We estimated acute toxicity of benzo[a]pyrene (B[a]P) using two cladoceran species, Ceriodaphnia reticulata and Daphnia magna, and also analyzed its impact on zooplankton community throughout an exposure experiment using small-scale mesocosms. LC(50) of B[a]P for C. reticulata and D. magna was 4.3 and 4.7 µg/l, respectively. However, individuals fed with Chlorella showed higher LC(50), 6.1 µg/l for C. reticulata and 8.0 µg/l for D. magna. In the exposure experiment, we examined the impact of B[a]P on zooplankton community using conceivable concentrations in the environment (5 and 10 µg/l) using typical zooplankton community in eutrophicated systems. Despite the residence time of B[a]P in the water column was short as recovery pattern was different among cladocerans and rotifers. Consequently, B[a]P showed insecticide-like impacts, suppressing cladoceran populations and inducing the dominance of rotifers particularly under high concentration (10 µg/l). Results have suggested that, even such short duration of B[a]P in the water body can have impact on zooplankton abundance and community structure. Since B[a]P easily precipitate to the bottom and rapidly disappears from the water body, careful monitoring and further assessment of the potential toxicity of polycyclic aromatic hydrocarbons are necessary. PMID:23358147

  13. Inclusion of copepod Acartia tonsa nauplii in the feeding of Centropomus undecimalis larvae increases stress resistance

    Directory of Open Access Journals (Sweden)

    Wanessa de Melo-Costa

    2015-09-01

    Full Text Available This research represents the first result of studies of the common snook Centropomus undecimalis larvae from broodstock matured in captivity in Brazil. The aim of this study was to evaluate if the inclusion of Acartia tonsa nauplii improves stress resistance of common snook larvae. The larvae were fed with: rotifers Brachionus plicatilis (10 to 15 mL-1; A. tonsa nauplii (0.25 to 0.5 mL-1 and rotifers (5 to 7.5 mL-1, and A. tonsa nauplii (0.12 to 0.25 mL-1. The average percentage of survival of the treatments was 11.9%. At 20 days of age, larvae were subjected to thermal stress. Subsequently, the stress resistance was evaluated. Common snook larvae fed B. plicatilis+A. tonsa reached a higher weight and length (7.5 ± 0.00 mg and 9.1 ± 0.23 mm, respectively and resisted more heat stress (87.4% than larvae fed other foods, indicating that the feed mixture is satisfactory as a starter diet for larvae of common snook. However, more research is needed to confirm these results.

  14. Remediation of mercury contaminated saltwater with functionalized silica coated magnetite nanoparticles.

    Science.gov (United States)

    Mohmood, Iram; Lopes, Cláudia B; Lopes, Isabel; Tavares, Daniela S; Soares, Amadeu M V M; Duarte, Armando C; Trindade, Tito; Ahmad, Iqbal; Pereira, Eduarda

    2016-07-01

    The study aimed to evaluate the efficiency of dithiocarbamate functionalized silica coated magnetite nanoparticles (NPs) for Hg decontamination of saltwater either contaminated with Hg alone or with As and Cd. For this, the residual levels of Hg in seawater were assessed and Hg-contaminated or Hg+As+Cd-contaminated seawater toxicity to aquatic biota, before and after the sorption process, was compared. The results showed that under highly competitive conditions (water salts, Cd and As), the removal of Hg from seawater, by using these magnetic NPs, for the lowest concentration (50μg/L) was superior to 98% and for the highest concentration (500μg/L) ranged between 61% to 67%. Despite the great affinity of the magnetic NPs for Hg, they were not effective at removing As and Cd from seawater. In relation to the ecotoxicity endpoints after remediation, the mixture with lower Hg concentration exhibited no toxicity to rotifer Brachionus plicatilis and bacteria Vibrio fischeri ; however, the mixture with higher concentration revealed toxicity. In addition, the toxicity of bacteria V. fischeri, rotifer B. plicatilis and algae Phaeodactylum tricornutum, whose responses where inhibited during its exposure to the non-remediate sample was considerably reduced after treatment with NPs. Furthermore, microalgae P. tricornutum appears to be most sensitive species while Artemia franciscana showed no toxic effects to the tested solutions. Both chemical and ecotoxicological approaches revealed a high efficiency for the remediation of Hg-contaminated saltwater.

  15. The Spatial Structure of Zooplankton Communities of Pedu Reservoir,Malaysia%The Spatial Structure of Zooplankton Communities of Pedu Reservoir, Malaysia

    Institute of Scientific and Technical Information of China (English)

    Amir Shah Ruddin Md Shah; Johan Ismail; Diana Latief; Wan Maznah Wan Omar

    2012-01-01

    A total of 22 species of zooplankton were identified from 8 sampling stations located in the limnetic zone of Pedu reservoir.The zooplankton community was dominated by rotifers (11 species),followed by cladocerans (9species) and copepods (2 species).Four species of zooplankton comprised of 3 rotifers,Brachionus quadridentata,Brachionus caudatus and Keratella cochlearis and one cladoceran,Ceriodaphnia cornuta were present at all sampling stations.Species richness was highest at Station 2 (17 species) followed by Station 4 and Station 8 (14 species),Station 5 (15 species),Station 7 (11 species),Station 6 (10 species),Station 3 (9 species) and Station 1 (7 species).With an exception of water transparency,all other water quality parameters such as temperature,dissolved oxygen,conductivity,pH and total dissolved solids were not significant when compared between sampling stations.The study found that station 5 which was located in a calm strait,protected from strong wave and wind was a suitable area for zooplankton growth and establishment.Factors supporting the findings included highest water transparency (3.4 m),rich in species numbers (15 species),high diversity index (0.950) and evenness index (0.808).

  16. Imazethapyr and imazapic, bispyribac-sodium and penoxsulam: Zooplankton and dissipation in subtropical rice paddy water

    Energy Technology Data Exchange (ETDEWEB)

    Reimche, Geovane B., E-mail: geovane_reimche@yahoo.com.br [Department of Plant Protection, Federal University of Santa Maria (UFSM), 97105-900 Santa Maria, RS (Brazil); Machado, Sérgio L.O. [Department of Plant Protection, Federal University of Santa Maria (UFSM), 97105-900 Santa Maria, RS (Brazil); Oliveira, Maria Angélica [Department of Biology, Federal University of Santa Maria, Santa Maria, RS (Brazil); Zanella, Renato; Dressler, Valderi Luiz; Flores, Erico M.M. [Department of Chemistry, Federal University of Santa Maria, Santa Maria, RS (Brazil); Gonçalves, Fábio F. [School of Chemistry and Food, Federal Foundation University of Rio Grande (FURG), 95500-000 Santo Antônio da Patrulha, RS (Brazil); Donato, Filipe F.; Nunes, Matheus A.G. [Department of Chemistry, Federal University of Santa Maria, Santa Maria, RS (Brazil)

    2015-05-01

    Herbicides are very effective at eliminating weed and are largely used in rice paddy around the world, playing a fundamental role in maximizing yield. Therefore, considering the flooded environment of rice paddies, it is necessary to understand the side effects on non-target species. Field experiment studies were carried out during two rice growing seasons in order to address how the commonly-used herbicides imazethapyr and imazapic, bispyribac-sodium and penoxsulam, used at recommended dosage, affect water quality and the non-target zooplankton community using outdoor rice field microcosm set-up. The shortest (4.9 days) and longest (12.2 days) herbicide half-life mean, estimated of the dissipation rate (k) is shown for imazethapyr and bispyribac-sodium, respectively. Some water quality parameters (pH, conductivity, hardness, BOD{sub 5}, boron, potassium, magnesium, phosphorus and chlorides) achieved slightly higher values at the herbicide treatment. Zooplankton community usually quickly recovered from the tested herbicide impact. Generally, herbicides led to an increase of cladocera, copepods and nauplius population, while rotifer population decreased, with recovery at the end of the experiment (88 days after herbicide treatment). - Highlights: • Selective herbicides in paddy rice fields, do not affect water quality. • Zooplankton communities show good response with herbicide dissipation. • The use of commercial herbicide mixture has strong effects on freshwater Rotifers.

  17. Eco-evolutionary feedback promotes Red Queen dynamics and selects for sex in predator populations.

    Science.gov (United States)

    Haafke, Julia; Abou Chakra, Maria; Becks, Lutz

    2016-03-01

    Although numerous hypotheses exist to explain the overwhelming presence of sexual reproduction across the tree of life, we still cannot explain its prevalence when considering all inherent costs involved. The Red Queen hypothesis states that sex is maintained because it can create novel genotypes with a selective advantage. This occurs when the interactions between species induce frequent environmental change. Here, we investigate whether coevolution and eco-evolutionary feedback dynamics in a predator-prey system allows for indirect selection and maintenance of sexual reproduction in the predator. Combining models and chemostat experiments of a rotifer-algae system we show a continuous feedback between population and trait change along with recurrent shifts from selection by predation and competition for a limited resource. We found that a high propensity for sex was indirectly selected and was maintained in rotifer populations within environments containing these eco-evolutionary dynamics; whereas within environments under constant conditions, predators evolved rapidly to lower levels of sex. Thus, our results indicate that the influence of eco-evolutionary feedback dynamics on the overall evolutionary change has been underestimated. PMID:26899793

  18. Photochemical fate and eco-genotoxicity assessment of the drug etodolac

    International Nuclear Information System (INIS)

    The photochemical behavior of etodolac was investigated under various irradiation conditions. Kinetic data were obtained after irradiation of 10−4 M aqueous solutions by UVB, UVA and direct exposure to sunlight. The Xenon lamp irradiation was used in order to determine the photodegradation quantum yield under sun-simulated condition (ϕsun). The value was determined to be = 0.10 ± 0.01. In order to obtain photoproducts and for mechanistic purposes, experiments were carried out on more concentrated solutions by exposure to sunlight and to UVA and UVB lamps. The drug underwent photooxidative processes following an initial oxygen addition to the double bond of the five membered ring and was mainly converted into a spiro compound and a macrolactam. Ecotoxicity tests were performed on etodolac, its photostable spiro derivative and its sunlight irradiation mixture on two different aquatic trophic levels, plants (algae) and invertebrates (rotifers and crustaceans). Mutagenesis and genotoxicity were detected on bacterial strains. The results showed that only etodolac had long term effects on rotifers although at concentrations far from environmental detection values. A mutagenic and genotoxic potential was found for its derivative. - Highlights: • Photochemical transformation of etodolac occurs in the environment. • Etodolac was slightly toxic in the long term for some aquatic organisms. • A mutagenic and genotoxic potential was found for etodolac photostable derivative

  19. Sildenafil and tadalafil in simulated chlorination conditions: Ecotoxicity of drugs and their derivatives

    International Nuclear Information System (INIS)

    Chlorination experiments on two drugs (sildenafil and tadalafil) were performed mimicking the conditions of a typical wastewater treatment process. The main transformation products were isolated by chromatographic techniques (Thin Layer Chromatography (TLC), Column Chromatography (CC), High Performance Liquid Chromatography (HPLC)) and fully characterized employing Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS) analyses. The environmental effects of the parent compounds and transformation products were evaluated using an overall toxicity approach that considered aquatic acute and chronic toxicity on Brachionus calyciflorus and Ceriodaphnia dubia as well as mutagenesis and genotoxicity on bacterial strains. The results revealed that both parent drugs did not show high acute and chronic toxicity for the organisms utilized in the bioassays while, chronic exposure to chlorine derivatives caused inhibition of growth population on rotifers and crustaceans. A mutagenic potential was found for all the compounds investigated. - Highlights: • Simulated disinfection process of pharmaceuticals was performed. • Toxicity and genotoxicity of sildenafil, tadalafil and their derivatives were evaluated. • Chlorine derivatives caused chronic toxicity on rotifers and crustaceans. • A mutagenic potential was found for all the compounds investigated

  20. Taxonomy and Physiology of un-wanted bacterial flora in activated sludge process. Study in a pilot plant; Taxonomia y fisiologia de la flora bacteriana indeseable en el proceso de fangos activados. Estudio de una plant piloto

    Energy Technology Data Exchange (ETDEWEB)

    Berrocal Escobar, M.; Lopez Fernandez, C. L.; Arias Fernandez, M. E.; Perez Leblic, M. I.; Zapatero Martin, I.; Leton Garcia, P.; Garcia Calvo, E. [Universidad de Alcala de Henares. Madrid (Spain); Aznar Munoz, R.; Rodriguez Medina, P. [Departamento Tecnico y de Calidad de Seragua, S.A. Madrid (Spain)

    1998-12-31

    The activated sludge used in the wastewater depuration in treatment plants could be considered as an artificial microbial ecosystem in balance. In this community which is constituted by free and flocculated bacteria, protozoa, rotifers, nematodes and a few other invertebrates, the stability of the system is maintained by the continuous food competition. The breakdown of this stability due to a high proliferation of filametous bacteria drive to the phenomenon called bulking. Nowadays, to avoid bulking is one of the main objectives in research because is the main cause of the malfunction of wastewater depuration interfering with compaction, settling, thickening and, concentration of activated sludge. In the present work, a taxonomical and physiological study of the microbial community which carries out the cleaning of wastewater in an activated sludge system has been performed by using an airlift bioreactor working in continuous. Activated sludge coming from a conventional wastewater plant was used as inoculum (starter culture). The nutritional conditions and bioreactor system parameters in which the filamentous bacteria grow in excess have been established. Several of filamentous bacteria responsible for bulking have been identified: Sphaerotilus natans, type 021N, Nocardia spp., Microthrix parvicella, Thiotrix I, Thiotrix II, type 0803, type 0581, Nostocoida limicola I and III and, type 1863. In addition, protozoa of groups involved in the depuration process (free-swimming ciliates, attached ciliates, crawling ciliates, carnivorous ciliates, flagellates and amoebae) were observed as well as rotifer and nematode populations. (Author) 13 refs.

  1. Genetic ontogeny of pancreatic enzymes in Labrus bergylta larvae and the effect of feed type on enzyme activities and gene expression.

    Science.gov (United States)

    Hansen, Truls Wergeland; Folkvord, Arild; Grøtan, Espen; Sæle, Øystein

    2013-03-01

    A newly cultivated wrasse species, Labrus bergylta, have shown great potential for use in Atlantic salmon (Salmo salar) farms in the battle against sea lice (Lepeoptheirus salmonis) infections. Hatchery reared L. bergylta were studied from 2 to 55 DPH to examine the molecular basis of digestive ontogeny related to the pancreas. An isolated feeding trial was performed on 27-34 DPH larvae to compare the effect of diet on enzyme activity and the possible exogenous contribution by live feed. The following genes coding for key pancreatic enzymes were analyzed by qPCR: trypsin, Cyp7 A1, BAL, sPLA(2) 1B, amylase and pancreatic chitinase. Enzyme activity was measured on trypsin, neutral lipase, sPLA(2), amylase and chitinase in fed and unfed larvae. We did not observe any effects of the formulated diet v.s. rotifers on enzyme activities of neutral lipase, chitinase and sPLA(2). However, a probable feed-dependency was observed at a transcriptional level, where rotifers seem to stimulate upregulation. The regulation of BAL was the only exception, where an upregulation was observed after weaning both in the ontogeny series and the experimental part. Our data on pancreatic chitinase and amylase mRNA levels suggest the importance of carbohydrates in the diet of early larval and juvenile L. bergylta.

  2. Laboratory scale photobioreactor for high production of microalgae Rhodomonas salina used as food for intensive copepod cultures

    DEFF Research Database (Denmark)

    Thuy, Minh Vu Thi; Jepsen, Per Meyer; Hansen, Benni Winding;

    Introduction Microalgae are essential feeds for many cultured molluscs, larvae of marine fishes, crustaceans as well as other important live feeds including rotifers, Artemia and copepods (Muller-Feuga, 2000). Microalgae are grown either in open culture systems (ponds) or closed systems (photobio......Introduction Microalgae are essential feeds for many cultured molluscs, larvae of marine fishes, crustaceans as well as other important live feeds including rotifers, Artemia and copepods (Muller-Feuga, 2000). Microalgae are grown either in open culture systems (ponds) or closed systems...... tests on a laboratory scale PBR and upscale in the next phase. In the present study, R. salina was cultivated in laboratory scale tubular PBRs (2 × 45 l) for 18 to 30 days where the growth, biochemical composition and production of R. salina were recorded. Materials and methods The Rhodomonas salina...... was used to estimate the optimal cell density of R. salina in the PBRs. This model estimation was validated by the collected data from PBR experiments. As a result, suggestions for further improving of the PBR performance were provided. Results and discussions The maximal specific growth rate of R. salina...

  3. PRELIMINARY STUDIES ON THE ROLE OF PROTOZOA IN THE FOOD WEB OF DONGHU LAKE

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Plankton from Station I of Donghu Lake, an eutrophic lake, was divided into three groups (2-32 μm, 32-112 μm and >112 μm) by filtering the water sample through 2, 32, 112 μm pores. It was supposed that the 2-32 μm Protozoa (group 1) was fed on by the 32-112 μm Protozoa and small rotifers (group 2) and >112 μm large rotifers, cladocerans and copepods (group 3). The feeding rate of zooplankton in situ was estimated by counting the protozoan individuals and also by the 14C-NaHCO3 method. The P/B ratio of the small Protozoa (group 1) was 2.9 for 6 h and 1.2 for 24 h. The feeding rate of the 32-112 μm zooplankton on small Protozoa (2-32 μm) was about 2/3 the total feeding rate of zooplankton, and that of >112 μm zooplankton on the 2-32 μm Protozoa was 1/3 of the total feeding rate. The lower the density of feeders, the higher were the feeding rates. The daily production of the 2-32 μm protozoans was 1.559 mg/L, which equaled to 25% of the daily food consumption of other zooplankton. Isotope experiments showed result similar to that from the above direct counting method.

  4. Photochemical fate and eco-genotoxicity assessment of the drug etodolac

    Energy Technology Data Exchange (ETDEWEB)

    Passananti, Monica [Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, via Cintia, 4, 80126 Napoli (Italy); Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand (ICCF) UMR 6296, BP 10448, F-63000 Clermont-Ferrand (France); Lavorgna, Margherita [Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università di Napoli, Via Vivaldi 43, I-81100 Caserta (Italy); Iesce, Maria Rosaria, E-mail: iesce@unina.it [Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, via Cintia, 4, 80126 Napoli (Italy); DellaGreca, Marina [Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, via Cintia, 4, 80126 Napoli (Italy); Brigante, Marcello [Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand (ICCF) UMR 6296, BP 10448, F-63000 Clermont-Ferrand (France); Criscuolo, Emma [Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università di Napoli, Via Vivaldi 43, I-81100 Caserta (Italy); Cermola, Flavio [Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, via Cintia, 4, 80126 Napoli (Italy); Isidori, Marina, E-mail: marina.isidori@unina2.it [Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università di Napoli, Via Vivaldi 43, I-81100 Caserta (Italy)

    2015-06-15

    The photochemical behavior of etodolac was investigated under various irradiation conditions. Kinetic data were obtained after irradiation of 10{sup −4} M aqueous solutions by UVB, UVA and direct exposure to sunlight. The Xenon lamp irradiation was used in order to determine the photodegradation quantum yield under sun-simulated condition (ϕ{sub sun}). The value was determined to be = 0.10 ± 0.01. In order to obtain photoproducts and for mechanistic purposes, experiments were carried out on more concentrated solutions by exposure to sunlight and to UVA and UVB lamps. The drug underwent photooxidative processes following an initial oxygen addition to the double bond of the five membered ring and was mainly converted into a spiro compound and a macrolactam. Ecotoxicity tests were performed on etodolac, its photostable spiro derivative and its sunlight irradiation mixture on two different aquatic trophic levels, plants (algae) and invertebrates (rotifers and crustaceans). Mutagenesis and genotoxicity were detected on bacterial strains. The results showed that only etodolac had long term effects on rotifers although at concentrations far from environmental detection values. A mutagenic and genotoxic potential was found for its derivative. - Highlights: • Photochemical transformation of etodolac occurs in the environment. • Etodolac was slightly toxic in the long term for some aquatic organisms. • A mutagenic and genotoxic potential was found for etodolac photostable derivative.

  5. Remediation of mercury contaminated saltwater with functionalized silica coated magnetite nanoparticles.

    Science.gov (United States)

    Mohmood, Iram; Lopes, Cláudia B; Lopes, Isabel; Tavares, Daniela S; Soares, Amadeu M V M; Duarte, Armando C; Trindade, Tito; Ahmad, Iqbal; Pereira, Eduarda

    2016-07-01

    The study aimed to evaluate the efficiency of dithiocarbamate functionalized silica coated magnetite nanoparticles (NPs) for Hg decontamination of saltwater either contaminated with Hg alone or with As and Cd. For this, the residual levels of Hg in seawater were assessed and Hg-contaminated or Hg+As+Cd-contaminated seawater toxicity to aquatic biota, before and after the sorption process, was compared. The results showed that under highly competitive conditions (water salts, Cd and As), the removal of Hg from seawater, by using these magnetic NPs, for the lowest concentration (50μg/L) was superior to 98% and for the highest concentration (500μg/L) ranged between 61% to 67%. Despite the great affinity of the magnetic NPs for Hg, they were not effective at removing As and Cd from seawater. In relation to the ecotoxicity endpoints after remediation, the mixture with lower Hg concentration exhibited no toxicity to rotifer Brachionus plicatilis and bacteria Vibrio fischeri ; however, the mixture with higher concentration revealed toxicity. In addition, the toxicity of bacteria V. fischeri, rotifer B. plicatilis and algae Phaeodactylum tricornutum, whose responses where inhibited during its exposure to the non-remediate sample was considerably reduced after treatment with NPs. Furthermore, microalgae P. tricornutum appears to be most sensitive species while Artemia franciscana showed no toxic effects to the tested solutions. Both chemical and ecotoxicological approaches revealed a high efficiency for the remediation of Hg-contaminated saltwater. PMID:27039062

  6. Sildenafil and tadalafil in simulated chlorination conditions: Ecotoxicity of drugs and their derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Temussi, Fabio; DellaGreca, Marina; Pistillo, Paola; Previtera, Lucio; Zarrelli, Armando [UdR Napoli 4 INCA, Dipartimento di Scienze Chimiche, Complesso Universitario di Monte Sant' Angelo, Università Federico II, Via Cintia, I-80126 Napoli (Italy); Criscuolo, Emma; Lavorgna, Margherita; Russo, Chiara [Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università di Napoli, Via Vivaldi 43, I-81100 Caserta (Italy); Isidori, Marina, E-mail: marina.isidori@unina2.it [Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università di Napoli, Via Vivaldi 43, I-81100 Caserta (Italy)

    2013-10-01

    Chlorination experiments on two drugs (sildenafil and tadalafil) were performed mimicking the conditions of a typical wastewater treatment process. The main transformation products were isolated by chromatographic techniques (Thin Layer Chromatography (TLC), Column Chromatography (CC), High Performance Liquid Chromatography (HPLC)) and fully characterized employing Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS) analyses. The environmental effects of the parent compounds and transformation products were evaluated using an overall toxicity approach that considered aquatic acute and chronic toxicity on Brachionus calyciflorus and Ceriodaphnia dubia as well as mutagenesis and genotoxicity on bacterial strains. The results revealed that both parent drugs did not show high acute and chronic toxicity for the organisms utilized in the bioassays while, chronic exposure to chlorine derivatives caused inhibition of growth population on rotifers and crustaceans. A mutagenic potential was found for all the compounds investigated. - Highlights: • Simulated disinfection process of pharmaceuticals was performed. • Toxicity and genotoxicity of sildenafil, tadalafil and their derivatives were evaluated. • Chlorine derivatives caused chronic toxicity on rotifers and crustaceans. • A mutagenic potential was found for all the compounds investigated.

  7. Effect of algal food (Chlorella vulgaris concentration and inoculation density on the competition among three planktonic Brachionidae (Rotifera: Monogononta Efecto de la concentración de algas (Chlorella vulgaris y la densidad de inoculación sobre la competencia entre tres Brachionidae (Rotifera: Monogononta planctónicos

    Directory of Open Access Journals (Sweden)

    S.S.S. Sarma

    2008-08-01

    Full Text Available Competitive outcomes among three rotifer species (Anuraeopsis fissa, Brachionus havanaensis and B. angularis were quantified with different inoculation densities of two competing species at a time (0, 25, 50, 75 and 100% and using different algal (Chlorella vulgaris densities (0.2 x 10(6, 0.4 x 10(6 and 0.8 x 10(6 cells ml-1. In control cultures, when each species was grown alone, the population growth of rotifers increased with increasing food availability in the medium, but in mixed cultures, decreased with increasing proportion of the competing species. At low food level, compared to B. havanaensis, B. angularis had stronger negative impact on A. fissa. However, with increasing algal density, both species of Brachionus had similar but reduced impact on A. fissa. Population growth of B. havanaensis was more adversely affected by A. fissa than B. angularis at low and intermediate concentrations. At high food level, the impact of either A. fissa or B. angularis on the growth of B. havanaensis was similar. When grown alone, for a given food density, A. fissa was more numerically (4 to 6 times abundant than the other two species. The rate of population increase (r of rotifers increased with increasing food levels. Depending on the rotifer species and the test conditions, the r varied from -0.001 to 0.34 d-1. Results showed that the competitive outcome in the tested rotifers depended on the initial inoculation density of the competing species, the offered food concentration as well as the interaction of these two factors.Se evaluaron los resultados de la competencia entre tres especies de rotíferos (Anuraeopsis fissa, Brachionus havanaensis y B. angularis usando dos especies a la vez con diferentes densidades de inóculo (0, 25, 50, 75 y 100% y diferentes niveles de alga (Chlorella vulgaris; 0.2 x 10(6, 0.4 x 10(6 y 0.8 x 10(6 células ml-1. En cultivos monoespecíficos, utilizados como control, el crecimiento poblacional de rotíferos aument

  8. 净水厂生物活性炭池无脊椎动物群落结构研究%Study of the invertebrate community structure in a biological activated carbon filter

    Institute of Scientific and Technical Information of China (English)

    尤为; 王庆; 刘丽君; 杨宇峰

    2012-01-01

    调查了南方某净水厂生物活性炭(BAC)池中无脊椎动物的群落结构周年变化.共发现无脊椎动物26种(属或类).轮虫为优势类群,其次为桡足类及其无节幼体、枝角类、寡毛类.调查期间BAC池炭总管水中无脊椎动物的平均丰度是主臭氧后水的8.2倍,炭滤后水中无脊椎动物的平均丰度是炭滤前水的12~18.7倍.研究结果表明,BAC池是无脊椎动物滋生的重要场所.春夏两季BAC池中无脊椎动物增长较快,水温升高对BAC池中无脊椎动物滋生起促进作用.夏季和其他时期分别以桡足类和轮虫占据优势,存在着小型无脊椎动物(轮虫)向大型无脊椎动物(桡足类)演替的现象.%A study was carried out to investigate the invertebrate community structure changes in the biological activated carbon (BAC) filter of some water treatment plant in South China. Totally 26 kinds of invertebrate were discovered. Rotifers were dominant species, and the others are copepods, nauplii larvae, cladocerans, and oligochaetes in declining sequence. During the research, the average invertebrate abundance in the filter was 8. 2 times of that in post-inter-ozonation-water, and the average invertebrate abundance after filter was 12 to 18. 7 times of that before filter. The research showed that BAC filter was the major spot for invertebrate breeding. During summer and fall, the invertebrate in BAC grow faster than other seasons. The increase of water temperature could improve the invertebrate breeding. In summer and other seasons, the copepods and rotifer were the dominant species respectively, and the succession from small invertebrate (rotifer) to large invertebrate (copepods) also existed.

  9. 不同饵料对泥鳅苗种前期培育效果的研究%Effects of different initial feed on rearing of larva Misgurnus anguillicaudatus

    Institute of Scientific and Technical Information of China (English)

    何国森; 陈度煌; 曾占壮; 王剑锋; 王寿昆

    2015-01-01

    本文研究了蛋黄、轮虫、豆浆、脱脂奶粉、鳗鱼饲料、鱼粉和酵母粉等7种饵料对泥鳅苗种前期培育生长和存活的影响。经过21 d培育,结果显示,泥鳅在不同饵料条件下的生长速度和存活率存在显著差异(P <0.05),轮虫组生长速度较快,平均日增全长达到0.31 mm,最终存活率最高,达到39.5%;其次是蛋黄组,达到25.5%;其他组别最终成活率都较低。因此,在本试验条件下,轮虫作为泥鳅开口饵料效果最为理想。Bertalanffy、Gompertz和Logistic三种非线性生长模型均能很好地拟合泥鳅苗种生长曲线(R2=1.000),该期生长拐点在7~8日龄间。%The influence of seven different initial feed on growth and survival rate of larva Misgurnus anguilli-caudatus was studied in the laboratory,including egg yolk,rotifers,soybean milk,skimmed milk powder, eel feed,fishmeal and yeast powder. The results showed that after feeding for 21d,there were significant differences in growth rate and survival rate of larva M. anguillicaudatus (P<0.05),the group of rotifer had the highest growth rate,the average daily length reached 0.31mm,and had the highest final survival rate of 39.5%,followed by egg yolk group,which reached 25.5%,the final survival rates of other groups were very low. In conclusion,under the conditions of this experiment,the best diet of larva M. anguillicaudatus was rotifers. Three kinds of non-linear growth model,including bertalanffy,gompertz and logistic could fit loach fry growth curve well (R2 = 1.000),the inflection point of growth between 7-8 days.

  10. 砂垫层控制活性炭滤池无脊椎动物穿透研究%Penetration control of invertebrates in the granular activated carbon filtration process with sand bed

    Institute of Scientific and Technical Information of China (English)

    尹文超; 张金松; 刘丽君; 赵岩; 李拓; 林超

    2013-01-01

    In view of the aesthetic problem and potential threat to safe drinking water caused by invertebrates, a series different depth of sand beds were located under granular activated carbon ( GAC ) media in five pilot -GAC filtration (GACF) columns to restrict invertebrates' penetration into the distribution system. During the study period of 10 months, 7 groups of invertebrates ( rotifers and crustaceans as the predominant species) were detected in the filtrates of the five GACF columns. The experimental results indicated that invertebrates could be removed effectively with the added sand beds compared with the sand bed-free GACF column. The mean abundances of invertebrates decreased significantly with the increase of the depth of sand beds. The 46. 6 % of rotifers and 85. 5% of larger invertebrates (size > 200 μm) could be removed from the filtrate. Sand sizes had a greater impact on rotifers removal than larger invertebrates. Also increasing removal ratios of particle matter were detected with the sand beds added. Further data analysis showed that there was significant correlation between the mean values of particle counts and abundances of invertebrates in the filtrates.%为控制无脊椎动物穿透带来的过滤水感官问题和潜在的安全风险,添加一系列不同粒径和不同高度的砂垫层于5根活性炭(Granular activated carbon,GAC)滤柱中.在10个月的连续运行期间,滤柱出水中共检出7类无脊椎动物(其中轮虫和甲壳类生物为优势种群).结果表明:砂垫层的添加可以有效防止无脊椎动物的穿透,且随着砂垫层高度的增加去除率逐渐升高,轮虫和体长大于200 μm无脊椎动物的去除率分别达46.6%和85.5%,石英砂粒径对轮虫的去除影响较大;砂垫层可以有效去除水中颗粒物,且出水中颗粒数与无脊椎动物丰度显著相关.

  11. Zooplankton communities in a large prealpine lake, Lake Constance: comparison between the Upper and the Lower Lake

    Directory of Open Access Journals (Sweden)

    Gerhard MAIER

    2005-08-01

    Full Text Available The zooplankton communities of two basins of a large lake, Lake Constance, were compared during the years 2002 and 2003. The two basins differ in morphology, physical and chemical conditions. The Upper Lake basin has a surface area of 470 km2, a mean depth of 100 and a maximum depth of 250 m; the Lower Lake basin has a surface area of 62 km2, a mean depth of only 13 and a maximum depth of 40 m. Nutrient, chlorophyll-a concentrations and mean temperatures are somewhat higher in the Lower than in the Upper Lake. Total abundance of rotifers (number per m2 lake surface was higher and rotifer development started earlier in the year in the Lower than in the Upper Lake. Total abundance of crustaceans was higher in the Upper Lake in the year 2002; in the year 2003 no difference in abundance could be detected between the lake basins, although in summer crustacean abundance was higher in the Lower than in the Upper Lake. Crustacean communities differed significantly between lake basins while there was no apparent difference in rotifer communities. In the Lower Lake small crustaceans, like Bosmina spp., Ceriodaphnia pulchella and Thermocyclops oithonoides prevailed. Abundance (number per m2 lake surface of predatory cladocerans, large daphnids and large copepods was much lower in the Lower than in the Upper Lake, in particular during the summer months. Ordination with nonmetric multidimensional scaling (NMS separated communities of both lakes along gradients that correlated with temperature and chlorophyll a concentration. Clutches of copepods were larger in the Lower than in the Upper Lake. No difference could be detected in clutch size of large daphnids between lake basins. Our results show that zooplankton communities in different basins of Lake Constance can be very different. They further suggest that the lack of large crustaceans in particular the lack of large predatory cladocerans in the Lower Lake can have negative effects on growth and

  12. An ecosystem analysis of the activated sludge microbial community.

    Science.gov (United States)

    Yiannakopoulou, Trissevyene V

    2010-01-01

    This study was undertaken (i) to investigate the interactions of the activated sludge microbial community in a chemostat with the "environment", such as the substrate composition and variations, (ii) to investigate how these interactions affect the quality of the treated effluent and (iii) to determine the limits or applicability conditions to the indicators and to the prediction potential of the treated effluent quality. This work presents (a) the experimental results obtained from a reactor fed municipal wastewater (Data Set2-DS2) concerning the reactor's operating conditions and the microbial community of the sludge (b) comparisons between DS2 and an older Data Set (DS1) obtained when the reactor was fed synthetic substrate, all other experimental conditions being identical, and (c) simulation results and sensitivity analyses of two model runs (R1 and R2, corresponding to DS1 and DS2). The first trophic level (P(1)) of the DS2 microbial community consisted of bacteria, the second trophic level (P(2)) of bacteria-eating protozoa, rotifers and nematodes and the third trophic level (P(3)) of carnivorous protozoa and arthropods. Rotifers were an important constituent of the DS2 microbial community. The DS1 and DS1 communities differed in total size, trophic level sizes and species composition. Correlations between the major microbial groups of DS2 community and either loading rates or effluent quality attributes were generally low, but the correlation of bacteria with SVI and ammonia in the effluent was better. Also, the ratio of rotifers to protozoa in P(2) was correlated to BOD in the effluent. The results of this work indicate that predictions of the treated effluent quality based only on protozoa may not be safe. Sensitivity analysis of R2 run indicate that, when variation in Y and K(d) biokinetic coefficients of the sludge are combined with fluctuations in composition and quality of municipal wastewater entering the reactor, then sufficient significant

  13. Distribuição espacial e temporal de Kellicottia bostoniensis (Rousselet, 1908 (Rotifera em um grande reservatório tropical (reservatório de Furnas, Estado de Minas Gerais, Brasil Spatial and temporal distribution of Kellicottia bostoniensis (Rousselet, 1908 (Rotifera in a big tropical reservoir (Furnas Reservoir, state of Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Ricardo Motta Pinto-Coelho

    2002-05-01

    Full Text Available O rotífero Kellicottia bostoniensis é uma espécie planctônica comum na América do Norte, e em anos recentes, ela foi introduzida no Brasil. No sudeste do Brasil ela foi encontrada num pequeno reservatório eutrófico em Belo Horizonte e na bacia do rio Grande, no Reservatório de Furnas (20º 40’S - 46º 19’W. O objetivo do trabalho foi analisar a distribuição espacial e temporal desse rotífero ao longo de um gradiente trófico, em 12 pontos (3 no eixo central do reservatório e (9 em um dos seus principais tributários, o eixo do rio Sapucaí. As amostragens foram feitas em agosto e outubro/99 e março e julho/2000, através de arrastos verticais, com rede cilíndro-cônica de 68µm. Os organismos foram contados em câmara de Sedgwick-Rafter. Esse rotífero apareceu em toda a área amostrada, e os maiores valores de densidade foram observados em outubro e março, estação chuvosa, nos pontos meso e eutróficos. A ocorrência de K. bostoniensis nesse reservatório reflete sua alta adaptabilidade em ambientes tropicais.The rotifer Kellicottia bostoniensis is a common planktonic species in North America. This species has been introduced in Brazil recently. It is found in southeastern Brazil in a small eutrophic reservoir in Belo Horizonte (Minas Gerais state capital and in the Rio Grande Basin, Furnas reservoir (20º 40’ S- 46º 19’W. The aims of this study is to analyze this rotifer spatial and temporal distribution along a trophic gradient in 12 locations (3 in the reservoir central axis and (9 in one of its main tributaries, the Sapucaí River axis. The samplings were taken in August and October, 1999, and in March and July, 2000, through vertical tow, with a 68 µm cylindrical-conical net. The organisms were counted in a Sedgwick-Rafter cell. This rotifer was in the whole sampled area, and the higher densities were observed in October and March, rainy season, in the meso and eutrophic areas. The K. bostoniensis occurrence in

  14. Current status of zooplankton in reservoir R-3 of the 'Mayak' production association

    Energy Technology Data Exchange (ETDEWEB)

    Osipova, O.; Pryakhin, E. [Urals Research Center for Radiation Medicine - URCRM (Russian Federation); Ivanov, I. [FSUE Mayak PA (Russian Federation)

    2014-07-01

    One of the commonly used objects for the study of human influence on aquatic ecosystems is zooplankton. Zooplankton community is a sensitive component of biota in reservoir which can change their functional parameters and species composition in response to exposure to different factors. The role of zooplankton in the transformation of energy and in the biotic cycling of the substance is very important. The study of the responses of this element in the water ecosystem with anthropogenic influences, including radioactive contamination, is an important task. The object of the study was the zooplankton in the reservoir R-3, Chelyabinsk region, Russia. R-3 is located in the buffer zone of the 'Mayak' PA and is the storage for low-level radioactive waste. In addition to the high content of radionuclides (the average specific activity of {sup 90}Sr in water was 2.8 kBq/l, {sup 137}Cs - 0.7 kBq/l), this reservoir is characterized by high values of dichromate oxidizability and phosphate contamination. Previously, the study of the zooplankton of this reservoir was conducted in 1952, regular observations were not organized. Assessment of the current status of the community, more than half a century residing in the conditions of radioactive and chemical contamination, seems highly interesting. Sampling was carried out in 2011-2012 at three stations: in the upper, middle, and near the dam of the reservoir by the method of weighted average of samples with bathometer. Analysis of samples showed that the zooplankton community consists of the following major groups: rotifers and cladocerans and copepods crustaceans. In total in R-3 27 species of zooplankton, including 19 species of rotifers, 3 species of copepod and 3 species of cladocerans, as well as two species of ciliates were discovered. Zooplankton abundance in 2011 was 9±9 million individuals/m{sup 3} (given the mean and standard deviation), in 2012 - 26.0±0.9 million individuals/m{sup 3}. The main contribution

  15. Prey selectivity and functional response by larval red-eyed tetra Moenkhausia sanctaefilomenae (Steindachner, 1907 (Characiformes: Characidae

    Directory of Open Access Journals (Sweden)

    Jorge Gallardo Alanis

    2009-10-01

    Full Text Available Studies were carried out to quantify the functional response and prey selectivity of larval (1-5 weeks old of Moenkhausia sanctaefilomenae, a widely cultured ornamental fish, using four rotifers (Brachionus calyciflorus, B. havanaensis, B. patulus and B. rubens as prey. Regardless of larval age, B. havanaensis was not selected, while B. rubens and B. calyciflorus were preferred. B. patulus was selected only after three weeks. When fed B. calyciflorus, the larvae showed increased prey consumption with increasing age, but remained as plateau around 80 prey individuals. M. sanctaefilomenae consumed much lower individuals of both B. havanaensis and B. patulus, while B. rubens was consumed in higher numbers starting from the first week (about 35 ind. larva-1 45 min.-1. Thus, the maximum number of individuals of each Brachionus species consumed by the larval M. sanctaefilomenae showed significant (p<0.05 differences among the prey types.

  16. Evaluation of primary and secondary production using wastewater as a culture medium.

    Science.gov (United States)

    Nandini, S; Ramírez-García, Pedro; Sarma, S S S

    2010-10-01

    The ability of rotifers and cladocerans to convert primary to secondary production in wastewaters was tested. Scenedesmus acutus was cultured on Bold's (defined) medium, wastewater from the tertiary phase of water treatment and a mixture of both. The algal growth rates (µ) ranged from 0.4 to 0.7 day⁻¹, being highest in defined medium. The demographic characteristics of Brachionus rubens and Moina macrocopa were tested using algae at a density of 1.0 x 10⁶ cells mL⁻¹. Into each test jar, we introduced 20 neonates (Moina (0.28-0.57 day⁻¹). Brachionus had significantly higher growth rates on algae cultured on Bold medium than on treated wastewater while Moina grew significantly better on Scenedesmus cultured on Bold medium or a mixture of treated wastewater and Bold medium than on treated wastewater alone. PMID:19748945

  17. Population Dynamics of Biota on the Roots of Azolla microphylla Kaulfuss

    Directory of Open Access Journals (Sweden)

    NITA ETIKAWATI

    2000-01-01

    Full Text Available Azolla was a special fern that their associations with Anabaena azollae able to fix free nitrogen from air, to produce protein. Although by the ages, biota diversity those habits on the roots of Azolla increased and effected to protein concentration. The research was to find out population dynamics of biota on the roots of Azolla microphylla Kaulfuss and the growth peak. This study used Completely Randomized Design with 10 kinds of biota, i.e. bacteria, Fungi, Actinomycetes, Protozoa, Alga, Crustacean, Rotifers, Coelenterate, Insect and Molluscs, and it was used 3 replications. Research was conducted within 4 weeks and the populations of biota were observed every week. Data were statistically analyzed using Analysis Variant and Duncan’s Multiple Range Test. The population dynamics of biota on the roots of Azolla microphylla Kaulfuss were influenced on its quantity and composition, and the growth peak is done in 2nd week.

  18. Space-time Distribution Characteristics of Zooplankton and Water Quality Assessment in the Fuhe River%抚河干流浮游动物生物多样性调查及水质评价

    Institute of Scientific and Technical Information of China (English)

    计勇; 张洁; 麻夏; 樊后保

    2013-01-01

    对2010年12月与2011年7月抚河干流各监测断面中浮游动物类群的结构组成、优势类群进行了调查,并对抚河干流的水质进行了综合评价,旨在为抚河流域水质保护以及今后开展相关监测研究提供理论依据.结果表明,抚河干流浮游动物共检出4类41种,其中轮虫类最多,共计7科15属23种,占总数的56.10%;枝角类5科6属7种,占17.07%;桡足类与原生动物占26.83%.时间分布上,浮游动物丰度表现为丰水期大于枯水期,其中丰水期轮虫、枝角类、桡足类与原生动物密度分别为256、26、66、16 ind/L,枯水期分别为131、8、24、10 ind/L.空间分布上呈现中间小、两端大的特点,最大值出现在ST1监测站点李渡镇,最小值出现在ST3监测站点高坪.抚河干流浮游动物数量结构主要由轮虫类组成,生物量结构则主要由桡足类组成.抚河干流水质处于中富营养至富营养状况,为轻度至中度污染,污染最重的是ST3监测点高坪,最轻的是ST7监测站点南丰.%To provide a basis for protecting water quality,the population structure of zooplankton was investigated in the Fuhe river in December 2010 and July 2011,and the water quality evaluation was made for the main stream. There were 41 species of zooplankton,in which rotifers were the most. Among the rotifers,a total of 7 families, 15 genera and 23 species,accounted for 56. 10% of the total; Cladocerans consisted of 5 families,6 genera and 7 species,accounting for 17. 07%; Copepods and protozoan accounted for 26. 83%. As for temporal distribution,zooplankton abundance in the high water period was greater than in the low water period. The densities of rotifers, cladocerans,copepods and protozoan were 256,26,66 and 16 ind/L respectively,in the high water period,while they were 131,8,24 and 10 ind/L respectively in the low water period. It was found that the density of zooplankton was low at middle section. From the annual average of

  19. Current status of zooplankton in reservoir R-3 of the 'Mayak' production association

    International Nuclear Information System (INIS)

    One of the commonly used objects for the study of human influence on aquatic ecosystems is zooplankton. Zooplankton community is a sensitive component of biota in reservoir which can change their functional parameters and species composition in response to exposure to different factors. The role of zooplankton in the transformation of energy and in the biotic cycling of the substance is very important. The study of the responses of this element in the water ecosystem with anthropogenic influences, including radioactive contamination, is an important task. The object of the study was the zooplankton in the reservoir R-3, Chelyabinsk region, Russia. R-3 is located in the buffer zone of the 'Mayak' PA and is the storage for low-level radioactive waste. In addition to the high content of radionuclides (the average specific activity of 90Sr in water was 2.8 kBq/l, 137Cs - 0.7 kBq/l), this reservoir is characterized by high values of dichromate oxidizability and phosphate contamination. Previously, the study of the zooplankton of this reservoir was conducted in 1952, regular observations were not organized. Assessment of the current status of the community, more than half a century residing in the conditions of radioactive and chemical contamination, seems highly interesting. Sampling was carried out in 2011-2012 at three stations: in the upper, middle, and near the dam of the reservoir by the method of weighted average of samples with bathometer. Analysis of samples showed that the zooplankton community consists of the following major groups: rotifers and cladocerans and copepods crustaceans. In total in R-3 27 species of zooplankton, including 19 species of rotifers, 3 species of copepod and 3 species of cladocerans, as well as two species of ciliates were discovered. Zooplankton abundance in 2011 was 9±9 million individuals/m3 (given the mean and standard deviation), in 2012 - 26.0±0.9 million individuals/m3. The main contribution was that of rotifers: 88.5 % of the

  20. Molecular Identification of a Species in Genus Nannochloropsis

    Institute of Scientific and Technical Information of China (English)

    LI Si; PAN Kehou; ZHU Baohua; MA Xiaolei; LIANG Xin; YANG Guanpin

    2011-01-01

    Nannochloropsis is a genus of marine eukaryotic unicellular algae,which belongs to class Eustigmatophyceae.The species of Nannochloropsis which are fine rotifer feed and rich in eicosapentaenoic acid (EPA) are economically important.Species in this genus are usually 2-5μm in size and are morphologically similar,which makes their identification difficult.We obtained a monoclone of Nannochloropsis with plating method in this study.DNA was extracted and the quality was determined by restriction enzyme digestion and spectrophotometer analysis.The DNA extracted was used to amplify the sequences of 18S ribosomal RNA gene,ITS region of ribosomal RNA transcription unit and rbcL gene.The phylogenetic analysis was carried out by constructing the neighbor-joining trees with Tamura-Nei distances.The phylogenetic analysis showed that the monoclone is N.oceanica.

  1. Genetic determinants of mate recognition in Brachionus manjavacas (Rotifera

    Directory of Open Access Journals (Sweden)

    Kubanek Julia

    2009-09-01

    Full Text Available Abstract Background Mate choice is of central importance to most animals, influencing population structure, speciation, and ultimately the survival of a species. Mating behavior of male brachionid rotifers is triggered by the product of a chemosensory gene, a glycoprotein on the body surface of females called the mate recognition pheromone. The mate recognition pheromone has been biochemically characterized, but little was known about the gene(s. We describe the isolation and characterization of the mate recognition pheromone gene through protein purification, N-terminal amino acid sequence determination, identification of the mate recognition pheromone gene from a cDNA library, sequencing, and RNAi knockdown to confirm the functional role of the mate recognition pheromone gene in rotifer mating. Results A 29 kD protein capable of eliciting rotifer male circling was isolated by high-performance liquid chromatography. Two transcript types containing the N-terminal sequence were identified in a cDNA library; further characterization by screening a genomic library and by polymerase chain reaction revealed two genes belonging to each type. Each gene begins with a signal peptide region followed by nearly perfect repeats of an 87 to 92 codon motif with no codons between repeats and the final motif prematurely terminated by the stop codon. The two Type A genes contain four and seven repeats and the two Type B genes contain three and five repeats, respectively. Only the Type B gene with three repeats encodes a peptide with a molecular weight of 29 kD. Each repeat of the Type B gene products contains three asparagines as potential sites for N-glycosylation; there are no asparagines in the Type A genes. RNAi with Type A double-stranded RNA did not result in less circling than in the phosphate-buffered saline control, but transfection with Type B double-stranded RNA significantly reduced male circling by 17%. The very low divergence between repeat units

  2. Zooplankton from Lake Magelungen, Central Sweden 1960-1963

    International Nuclear Information System (INIS)

    The investigation of the zooplankton of Lake Magelungen, Central Sweden, was carried out over a period of three years. The aim of the investigation was to illustrate the qualitative and quantitative composition of the zooplankton before the release of waste water from the Aagesta Heat and Power Station began. Vertical sampling series were collected once a month at three different stations in the lake. The highest volumes of zooplankton were obtained in the summer. The ciliates predominated when the conditions were unfavourable for other zooplankton, as in winter just below the ice. The rotifers dominated during and immediately after the spring circulation. With one exception the crustaceans reached their peak volume values in August or September. The composition of the zooplankton indicates that Lake Magelungen is highly eutrophic

  3. Individual and population variation in invertebrates revealed by Inter-simple Sequence Repeats (ISSRs

    Directory of Open Access Journals (Sweden)

    Patrick Abbot

    2001-08-01

    Full Text Available PCR-based molecular markers are well suited for questions requiring large scale surveys of plant and animal populations. Inter-simple Sequence Repeats or ISSRs are analyzed by a recently developed technique based on the amplification of the regions between inverse-oriented microsatellite loci with oligonucleotides anchored in microsatellites themselves. ISSRs have shown much promise for the study of the population biology of plants, but have not yet been explored for similar studies of animals. The value of ISSRs is demonstrated for the study of animal species with low levels of within-population variation. Sets of primers are identified which reveal variation in two aphid species, Acyrthosiphon pisum and Pemphigus obesinymphae, in the yellow fever mosquito Aedes aegypti, and in a rotifer in the genus Philodina.

  4. Continuous Exposure Of Vibrio Anguillarum To Tropodithietic Acid: Genetic Changes And Influence On Virulence

    DEFF Research Database (Denmark)

    Rasmussen, Bastian Barker; D'Alvise, Paul; Grotkjær, Torben;

    2015-01-01

    exposure affects V. anguillarum focusing on the development of resistance towards TDA and changes in virulence.Methods: Seven lineages of V. anguillarum were exposed to increasing TDA concentrations over 300-400 generations and were subsequently genome sequenced. Virulence of the lineages is currently......Introduction: The fish pathogen Vibrio anguillarum is a major problem in aquaculture causing Vibriosis. Bacteria of the Roseobacter clade can antagonize pathogenic vibrios in cultures in live feed such as microalgae, rotifers and Artemia, as well as in fish larvae. Therefore, roseobacters could...... being tested in fish cell infection trials.Results: Following exposure, four linages reached 1.75 x wild-type MIC and three reached 1.5 x wild-type MIC. Genome sequencing revealed no major changes in the genomes of the lineages. The only virulence-related gene affected was fliM, encoding a flagella...

  5. Acute and chronic toxicity testing of bisphenol A with aquatic invertebrates and plants.

    Science.gov (United States)

    Mihaich, Ellen M; Friederich, Urs; Caspers, Norbert; Hall, A Tilghman; Klecka, Gary M; Dimond, Stephen S; Staples, Charles A; Ortego, Lisa S; Hentges, Steven G

    2009-07-01

    Bisphenol A (BPA, 4,4'-isopropylidine diphenol) is a commercially important chemical used primarily as an intermediate in the production of polycarbonate plastic and epoxy resins. Extensive effect data are currently available, including long-term studies with BPA on fish, amphibians, crustaceans, and mollusks. The aim of this study was to perform additional tests with a number of aquatic invertebrates and an aquatic plant. These studies include acute tests with the midge (Chironomus tentans) and the snail (Marisa cornuarietis), and chronic studies with rotifers (Brachionus calyciflorus), amphipods (Hyalella azteca), and plants (Lemna gibba). The effect data on different aquatic invertebrate and plant species presented in this paper correspond well with the effect and no-effect concentrations (NOECs) available from invertebrate studies in the published literature and are within the range found for other aquatic species tested with BPA. PMID:19327838

  6. Effects on parathion on the ecology of a eutrophic aquatic ecosystem: limnocorral experiment

    International Nuclear Information System (INIS)

    Repetitive exposure of a eutrophic fish pond ecosystem, enclosed in limnocorrals, to 30 ppb parathion resulted in elimination of the potentially dominant zooplankton species, Moina micrura. Consequently, the populations of the rotifers Brachionus and Asplanchna markedly increased. Changes in the zooplankton composition and abundance were followed by increased fluctuations in phytoplankton biomass, phytoplankton photosynthesis, plankton respiration and community metabolism. Similar responses to parathion treatment were observed in previous studies under fish pond conditions. In the presence of fish the effect of parathion on the ecosystem was generally less pronounced and not uniform. The collapse of the zooplankton community and the rapid changes in limnological conditions in the control (untreated) limnocorrals severely limited the duration of the experiment. The results suggest that under eutrophic conditions, small enclosures may be useful for evaluation of the effect of toxicants on the ecosystem only in short term experiments with short lived chemicals. (author)

  7. Survival to reproductive cessation drives variation in post-reproductive lifespan

    DEFF Research Database (Denmark)

    Proske, Beate; Burger, Oskar; Levitis, Daniel

    2014-01-01

    How many post-reproductive individuals are found in a population depends on how many individuals survive to reproductive cessation and how long they live thereafter. Post-reproductive Representation (PrR), a measure of post-reproductive lifespan intended for interspecific comparisons, allows a cl......-reproductive. Research on the evolution of post-reproductive lifespan should take into account the primary importance of survival to reproductive cessation, rather than focusing on the length of life thereafter....... the majority of variation in PrR among a group of small cohorts of rotifers, and among several historical Swedish cohorts. We emphasize that women are distinct from other primates in the proportion reaching reproductive cessation, but not in the proportion of adult life-expectancy that is post...

  8. Keratella lenzi (Hauer, 1953: a new occurrence for Acre State, Brazil, specifically in Igarapé Jesumira located in Parque Nacional da Serra do Divisor

    Directory of Open Access Journals (Sweden)

    Erlei Cassiano Keppeler

    2010-06-01

    Full Text Available Rotifers are very important freshwater plankton, and they occupy an ecological niche of small filter feeders. The extent of their distribution includes floodplains, because they tolerate environmental changes caused by an increase in water levels that leads to a diversification of niches. However, the biodiversity of floodplains is still poorly known, especially in Northeast Brazil in the state of Acre. The organisms were collected usingpond nets with a 50μm mesh size, and they were preserved in 4% formaldehyde. This paper registers the first occurrence of Keratella lenzi in Acre State. The species was identified in plankton samples from Igarapé Jesumira (7º28’10.2”S and 73º33’54.6”.

  9. Cryptic population dynamics: rapid evolution masks trophic interactions.

    Directory of Open Access Journals (Sweden)

    Takehito Yoshida

    2007-09-01

    Full Text Available Trophic relationships, such as those between predator and prey or between pathogen and host, are key interactions linking species in ecological food webs. The structure of these links and their strengths have major consequences for the dynamics and stability of food webs. The existence and strength of particular trophic links has often been assessed using observational data on changes in species abundance through time. Here we show that very strong links can be completely missed by these kinds of analyses when changes in population abundance are accompanied by contemporaneous rapid evolution in the prey or host species. Experimental observations, in rotifer-alga and phage-bacteria chemostats, show that the predator or pathogen can exhibit large-amplitude cycles while the abundance of the prey or host remains essentially constant. We know that the species are tightly linked in these experimental microcosms, but without this knowledge, we would infer from observed patterns in abundance that the species are weakly or not at all linked. Mathematical modeling shows that this kind of cryptic dynamics occurs when there is rapid prey or host evolution for traits conferring defense against attack, and the cost of defense (in terms of tradeoffs with other fitness components is low. Several predictions of the theory that we developed to explain the rotifer-alga experiments are confirmed in the phage-bacteria experiments, where bacterial evolution could be tracked. Modeling suggests that rapid evolution may also confound experimental approaches to measuring interaction strength, but it identifies certain experimental designs as being more robust against potential confounding by rapid evolution.

  10. Effect of paracetamol and diclofenac on population growth of Plationus patulus and Moina macrocopa.

    Science.gov (United States)

    Sarma, S S S; González-Pérez, Brenda Karen; Moreno-Gutiérrez, Rosa Martha; Nandini, S

    2014-01-01

    Two non-steroidal anti-inflammatory commonly used in Mexico are paracetamol and diclofenac. These drugs reach natural waterbodies transport through the hydrological areas of agriculture and effluent treatment plants and can affect plankton. In this study, we quantified the chronic effects of paracetamol and sodium diclofenac on the population dynamics of the rotifer Plationus patulus and the cladoceran Moina macrocopa under laboratory conditions. Both these species of zooplankton are common in freshwaters and are sensitive to chemicals in the medium. Our results showed that densities of both P. patulus and M. macrocopa decreased with increasing levels of both the analgesic drugs. Both zooplankton species did not survive beyond when paracetamol was applied at 32 mg I(-1) in the medium. Diclofenac in general had more adverse effect than paracetamol for either zooplankton species. P. patulus was more sensitive than M. macrocopa to both analgesic drugs. When diclofenac was present in the medium at > or = 12.5 mg I(-1), rotifer reproduction was inhibited, while the tested cladocerans continued to grow but to lower densities compared to control. The rate of population increase (r) per day of P. patulus and M. macrocopa was significantly and inversely related to the concentration of paracetamol and diclofenac in the medium. However, the relationship between r and drug concentration differed depending on the zooplankton species and drug. In controls, the r of P. patulus was 0.18 d(-1), for M. macrocopa under similar conditions, it was slightly lower (0.16 d(-1)). The rvalues of both zooplankton populations became negative (-0.10 to -0.15 d(-1)) when exposed to paracetamol at 32 mg l(-1) or diclofenac at 25 mg I(-1). PMID:24579527

  11. Elaphoidella grandidieri (Harpacticoida: Copepoda): demographic characteristics and possible use as live prey in aquaculture.

    Science.gov (United States)

    Nandini, S; Nunez Ortiz, Alma Rosa; Sarma, S S S

    2011-07-01

    In freshwater ecosystems, rotifers and cladocerans are ideal prey for fish larvae whereas copepods, due to their purported low growth rate and predatory tendency, are not. We recently isolated the parthenogenetic Elaphoidella grandidieri (Gueme et Richard, 1893) a benthic freshwater harpacticoid, from a fish farm in the State of Morelos, central Mexico and tested its potential as a live prey organism for larval vertebrates. Population growth and life table demography experiments were conducted, in 100 ml recipients with 50 ml of test medium on a diet of Scenedesmus acutus at a density of 1.0 X 10(6) cell ml(-1); the former on live algae alone while the latter on live algae as well as detritus. We also conducted experiments to document the prey preference for this copepod by the larval Ameca splendens (Pisces: Goodeidae) and Ambystoma mexicanum (Amphibia: Ambystomatidae), fed the rotifer Plationus patulus, the ostracod Heterocypris incongruens, and the cladocerans Moina macrocopa and Daphnia pulex. Elaphoidella grandidieri is relatively easy to maintain under laboratory conditions, reaching densities (copepodites and adults) of more than 10,000 l(-1). The generation time ranged between 30-45 days, depending on the diet. The net reproductive rate was as high as 60 nauplii female(-1) day (1). Population growth rates ranged between 0.03 and 0.11 d(-1), live algae being the superior diet compared to detritus. Both predators showed no preference for E. grandidieri, but in the absence of alternate prey they consumed 80% of the harpacticoids offered. The data have been discussed in relation to the potential of E. grandidierias live food for aquaculture. PMID:22315830

  12. Dietary β-glucan (MacroGard®) enhances survival of first feeding turbot (Scophthalmus maximus) larvae by altering immunity, metabolism and microbiota.

    Science.gov (United States)

    Miest, Joanna J; Arndt, Carmen; Adamek, Mikolaj; Steinhagen, Dieter; Reusch, Thorsten B H

    2016-01-01

    Reflecting the natural biology of mass spawning fish aquaculture production of fish larvae is often hampered by high and unpredictable mortality rates. The present study aimed to enhance larval performance and immunity via the oral administration of an immunomodulator, β-glucan (MacroGard(®)) in turbot (Scophthalmus maximus). Rotifers (Brachionus plicatilis) were incubated with or without yeast β-1,3/1,6-glucan in form of MacroGard(®) at a concentration of 0.5 g/L. Rotifers were fed to first feeding turbot larvae once a day. From day 13 dph onwards all tanks were additionally fed untreated Artemia sp. nauplii (1 nauplius ml/L). Daily mortality was monitored and larvae were sampled at 11 and 24 dph for expression of 30 genes, microbiota analysis, trypsin activity and size measurements. Along with the feeding of β-glucan daily mortality was significantly reduced by ca. 15% and an alteration of the larval microbiota was observed. At 11 dph gene expression of trypsin and chymotrypsin was elevated in the MacroGard(®) fed fish, which resulted in heightened tryptic enzyme activity. No effect on genes encoding antioxidative proteins was observed, whilst the immune response was clearly modulated by β-glucan. At 11 dph complement component c3 was elevated whilst cytokines, antimicrobial peptides, toll like receptor 3 and heat shock protein 70 were not affected. At the later time point (24 dph) an anti-inflammatory effect in form of a down-regulation of hsp 70, tnf-α and il-1β was observed. We conclude that the administration of MacroGard(®) induced an immunomodulatory response and could be used as an effective measure to increase survival in rearing of turbot. PMID:26564474

  13. Multi-linear regression analysis, preliminary biotic ligand modeling, and cross species comparison of the effects of water chemistry on chronic lead toxicity in invertebrates.

    Science.gov (United States)

    Esbaugh, A J; Brix, K V; Mager, E M; De Schamphelaere, K; Grosell, M

    2012-03-01

    The current study examined the chronic toxicity of lead (Pb) to three invertebrate species: the cladoceran Ceriodaphnia dubia, the snail Lymnaea stagnalis and the rotifer Philodina rapida. The test media consisted of natural waters from across North America, varying in pertinent water chemistry parameters including dissolved organic carbon (DOC), calcium, pH and total CO(2). Chronic toxicity was assessed using reproductive endpoints for C. dubia and P. rapida while growth was assessed for L. stagnalis, with chronic toxicity varying markedly according to water chemistry. A multi-linear regression (MLR) approach was used to identify the relative importance of individual water chemistry components in predicting chronic Pb toxicity for each species. DOC was an integral component of MLR models for C. dubia and L. stagnalis, but surprisingly had no predictive impact on chronic Pb toxicity for P. rapida. Furthermore, sodium and total CO(2) were also identified as important factors affecting C. dubia toxicity; no other factors were predictive for L. stagnalis. The Pb toxicity of P. rapida was predicted by calcium and pH. The predictive power of the C. dubia and L. stagnalis MLR models was generally similar to that of the current C. dubia BLM, with R(2) values of 0.55 and 0.82 for the respective MLR models, compared to 0.45 and 0.79 for the respective BLMs. In contrast the BLM poorly predicted P. rapida toxicity (R(2)=0.19), as compared to the MLR (R(2)=0.92). The cross species variability in the effects of water chemistry, especially with respect to rotifers, suggests that cross species modeling of invertebrate chronic Pb toxicity using a C. dubia model may not always be appropriate.

  14. Dietary β-glucan (MacroGard®) enhances survival of first feeding turbot (Scophthalmus maximus) larvae by altering immunity, metabolism and microbiota.

    Science.gov (United States)

    Miest, Joanna J; Arndt, Carmen; Adamek, Mikolaj; Steinhagen, Dieter; Reusch, Thorsten B H

    2016-01-01

    Reflecting the natural biology of mass spawning fish aquaculture production of fish larvae is often hampered by high and unpredictable mortality rates. The present study aimed to enhance larval performance and immunity via the oral administration of an immunomodulator, β-glucan (MacroGard(®)) in turbot (Scophthalmus maximus). Rotifers (Brachionus plicatilis) were incubated with or without yeast β-1,3/1,6-glucan in form of MacroGard(®) at a concentration of 0.5 g/L. Rotifers were fed to first feeding turbot larvae once a day. From day 13 dph onwards all tanks were additionally fed untreated Artemia sp. nauplii (1 nauplius ml/L). Daily mortality was monitored and larvae were sampled at 11 and 24 dph for expression of 30 genes, microbiota analysis, trypsin activity and size measurements. Along with the feeding of β-glucan daily mortality was significantly reduced by ca. 15% and an alteration of the larval microbiota was observed. At 11 dph gene expression of trypsin and chymotrypsin was elevated in the MacroGard(®) fed fish, which resulted in heightened tryptic enzyme activity. No effect on genes encoding antioxidative proteins was observed, whilst the immune response was clearly modulated by β-glucan. At 11 dph complement component c3 was elevated whilst cytokines, antimicrobial peptides, toll like receptor 3 and heat shock protein 70 were not affected. At the later time point (24 dph) an anti-inflammatory effect in form of a down-regulation of hsp 70, tnf-α and il-1β was observed. We conclude that the administration of MacroGard(®) induced an immunomodulatory response and could be used as an effective measure to increase survival in rearing of turbot.

  15. An integrated closed system for fish-plankton aquaculture in Amazonian fresh water.

    Science.gov (United States)

    Gilles, S; Ismiño, R; Sánchez, H; David, F; Núñez, J; Dugué, R; Darias, M J; Römer, U

    2014-08-01

    A prototype of an integrated closed system for fish-plankton aquaculture was developed in Iquitos (Peruvian Amazonia) in order to cultivate the Tiger Catfish, Pseudoplatystoma punctifer (Castelnau, 1855). This freshwater recirculating system consisted of two linked sewage tanks with an intensive rearing unit (a cage) for P. punctifer placed in the first, and with a fish-plankton trophic chain replacing the filters commonly used in clear water closed systems. Detritivorous and zooplanktivorous fishes (Loricariidae and Cichlidae), maintained without external feeding in the sewage volume, mineralized organic matter and permitted the stabilization of the phytoplankton biomass. Water exchange and organic waste discharge were not necessary. In this paper we describe the processes undertaken to equilibrate this ecosystem: first the elimination of an un-adapted spiny alga, Golenkinia sp., whose proliferation was favored by the presence of a small rotifer, Trichocerca sp., and second the control of this rotifer proliferation via the introduction of two cichlid species, Acaronia nassa Heckel, 1840 and Satanoperca jurupari Heckel, 1840, in the sewage part. This favored some development of the green algae Nannochloris sp. and Chlorella sp. At that time we took the opportunity to begin a 3-month rearing test of P. punctifer. The mean specific growth rate and feed conversion ratio (FCR) of P. punctifer were 1.43 and 1.27, respectively, and the global FCR, including fish in the sewage part, was 1.08. This system has proven to be suitable for growing P. punctifer juveniles out to adult, and provides several practical advantages compared with traditional recirculating clear water systems, which use a combination of mechanical and biological filters and require periodic waste removal, leading to water and organic matter losses. PMID:24849417

  16. Meio- and Macrofaunal Communities in Artificial Water-Filled Tree Holes: Effects of Seasonality, Physical and Chemical Parameters, and Availability of Food Resources.

    Directory of Open Access Journals (Sweden)

    Christoph Ptatscheck

    Full Text Available In this study we investigated the dynamics of meiofaunal and macrofaunal communities in artificial water-filled tree holes. The abundances and, for the first time, biomasses and secondary production rates of these communities were examined. The experimental set-up consisted of 300 brown plastic cups placed in temperate mixed forests and sampled five times over a period of 16 months to determine the impact of (i seasonal events, (ii physicochemical parameters, and (iii food resources on the tree hole metazoans.Metazoan organisms, especially the meiofauna (rotifers and nematodes occupied nearly all of the cups (> 99% throughout the year. Between 55% and 99% of the metazoan community was represented by rotifers (max. 557,000 individuals 100 cm-2 and nematodes (max. 58,000 individuals 100 cm-2. Diptera taxa, particularly Dasyhelea sp. (max. 256 individuals 100 cm-2 dominated the macrofaunal community. Macrofauna accounted for the majority of the metazoan biomass, with a mean dry weight of 5,800 μg 100 cm-2 and an annual production rate of 20,400 μg C 100 cm-2, whereas for meiofauna mean biomass and annual production were 100 μg 100 cm-2 and 5,300 μg C 100 cm-2, respectively. The macrofaunal taxa tended to show more fluctuating population dynamic while the meiofaunal dynamic was rather low with partly asynchronous development. Seasonality (average temperature and rain intervals had a significant impact on both meiofauna and macrofauna. Furthermore, bottom-up control (chlorophyll-a and organic carbon, mainly attributable to algae, was a significant factor that shaped the metazoan communities. In contrast, physicochemical water parameters had no evident influence. 23.7% of organism density distribution was explained by redundancy analysis (RDA indicating a high dynamic and asynchrony of the systems.

  17. Zooplankton diversity and physico-chemical conditions in three perennial ponds of Virudhunagar district, Tamilnadu.

    Science.gov (United States)

    Rajagopal, T; Thangamani, A; Sevarkodiyone, S P; Sekar, M; Archunan, G

    2010-05-01

    Plankton diversity and physico-chemical parameters are an important criterion for evaluating the suitability of water for irrigation and drinking purposes. In this study we tried to assess the zooplankton species richness, diversity and evenness and to predict the state of three perennial ponds according to physico-chemical parameters. A total of 47 taxa were recorded: 24 rotifers, 9 copepods, 8 cladocerans, 4 ostracods and 2 protozoans. More number of zooplankton species were recorded in Chinnapperkovil pond (47 species) followed by Nallanchettipatti (39 species) and Kadabamkulam pond (24 species). Among the rotifers, Branchionus sp. is abundant. Diaphanosoma sp. predominant among the cladocerans. Among copepods, numerical superiority was found in the case of Mesocyclopes sp. Cypris sp. repeated abundance among ostracoda. Present study revealed that zooplankton species richness (R1 and R2) was comparatively higher (R1: 4.39; R2: 2.13) in Chinnapperkovil pond. The species diversity was higher in the Chinnapperkovil pond (H': 2.53; N1: 15.05; N2: 15.75) as compared to other ponds. The water samples were analyzed for temperature, pH, electrical conductivity alkalinity salinity, phosphate, hardness, dissolved oxygen and biological oxygen demand. Higher value of physico-chemical parameters and zooplankton diversity were recorded in Chinnapperkovil pond as compared to other ponds. The zooplankton population shows positive significant correlation with physico-chemical parameters like, temperature, alkalinity phosphate, hardness and biological oxygen demand, whereas negatively correlated with rainfall and salinity. The study revealed that the presence of certain species like, Monostyla sp., Keratella sp., Lapadella sp., Leydigia sp., Moinodaphnia sp., Diaptomus sp., Diaphanosoma sp., Mesocyclopes sp., Cypris sp. and Brachionus sp. is considered to be biological indicator for eutrophication.

  18. Aeolian transport of biota with dust: A wind tunnel experiment

    Science.gov (United States)

    Rivas, J. A., Jr.; Gill, T. E.; Van Pelt, R. S.; Walsh, E.

    2015-12-01

    Ephemeral wetlands are ideal sources for dust emission, as well as repositories for dormant stages of aquatic invertebrates. An important component of invertebrate dispersal and colonization to new areas is the ability to be entrained into the atmosphere. Aquatic invertebrate eggs fall within the size of dust and sand grains (30-600μm), are less dense and aerodynamically shaped. We have shown previously that aquatic invertebrates can be dispersed long distances in dust storms but the extent of transport of taxa based on diapausing egg size/morphology has not been investigated. Here, we control the wind erosion process in a wind tunnel to test entrainment of diapausing stages of brine shrimp, clam shrimp, tadpole shrimp, fairy shrimp, Daphnia, and the rotifers Brachionus plicatilis and B. calyciflorus into the air by saltation. Diapausing eggs were mixed with sterilized wind-erodible soil. The soil/egg mixture was moistened with distilled water and air dried to form a crust. Dust was generated in a wind tunnel by releasing sand grains that act as saltator material similar to wind-entrained natural sands. Maximum wind velocity was 10m/s and entrained particles were sampled through an isokinetic horizontal intake opening. Aeolian sediment was collected from three points in the system; transfer section for coarse sediment, the pan subtending a settling chamber for finer saltation-sized sediment, and two paper filters for suspension-sized sediment. Samples were then passed through 250 and 350 μm sieves to remove abrader sand and rehydrated with various sterile media depending on the type of organism. We retrieved viable brine, fairy, and tadpole shrimp, ostracods, Daphnia, and diapausing eggs of the rotifers after hydration. This experiment demonstrates that resting stages of many invertebrates can be wind-eroded due to size and egg morphology and remain viable under controlled conditions mimicking dust emission.

  19. Spatially explicit genetic structure in the freshwater sponge Ephydatia fluviatilis (Linnaeus, 1759 within the framework of the monopolisation hypothesis

    Directory of Open Access Journals (Sweden)

    Livia Lucentini

    2013-02-01

    Full Text Available An apparent paradox is known for crustaceans, rotifers and bryozoans living in inland small water bodies: a potential for wide distribution due to the presence of resting stages is coupled with marked genetic differences between nearby water bodies, with enclave distributions masking clear phylogeographic patterns. According to the monopolisation hypothesis, this is due to the accumulation of resting stages, monopolising each water body. Freshwater sponges could represent a useful system to assess the generality of the mo- nopolisation hypothesis: these organisms i live in the same habitats as crustaceans, rotifers and bryozoans, ii produce resting stages that can accumulate, and iii have indeed a wide distribution. Currently, no studies on spatially explicit genetic differentiation on fresh- water sponges are available. The aim of the present study is to provide additional empirical evidence in support of the generality of the scenario for small aquatic animals with resting stages by analysing genetic diversity at different spatial scales for an additional model system, the freshwater sponge ephydatia fluviatilis (Linnaeus, 1759. We expected that system genetic variability would follow enclave distributions, no clear phylogeographical patterns would be present, and nearby unconnected water bodies would show markedly different populations for this new model too. We analysed the ribosomal internal transcribed spacer regions 5.8S-ITS2-28S, the D3 domain of 28S subunit, the mitochondrial Cytochrome c Oxidase I (COI and ten specific microsatellite markers of nine Italian and one Hungarian populations. Mitochondrial and nuclear sequences showed no or very low genetic polymorphism, whereas high levels of differentiation among populations and a significant polymorphism were observed using microsatellites. Microsatellite loci also showed a high proportion of private alleles for each population and an overall correlation between geographic and genetic

  20. Supplementation of Indigenous Lactobacillus Bacteria in Live Prey and as Water Additive to Larviculture of Portunus pelagicus (Linnaeus, 1758

    Directory of Open Access Journals (Sweden)

    A.D. Talpur

    2011-10-01

    Full Text Available Experimental trials were conducted to demarcate the effects of indigenous Lactobacillus probiotics as bioencapsulated in live prey (rotifers Brachionus plicatilis and Artemia franciscana and water additives together on the survival of blue swimming crab, Portunus pelagicus larvae. Three LAB probiotics L. plantarum, L. salivarius and L. rhamnosus at final concentration 1x107 cfu/mL were bioencapsulated in live prey added daily and same allowance was added to culture water on day 1, 3, 5, 7, 9, 11, 13 as a single isolates to treatments A, B, C and multi isolates to D with no probiotic added to control tanks. Bacteria were successfully accumulated in both rotifers and Artemia within two hours of incubation. Total viable count of bacteria in Artemia observed lower at sampling days in inoculated tanks compared to those at time of incubation, contrary it increased in controls and no Vibrio was determined in Artemia in LAB mixture isolate inoculated samples on the day 13. Highest LAB bacteria 4.10×103 was determined in Artemia on day 11 in those inoculated with mixture of LAB isolates. At the end of the trials, larvae treated with a mixture of LAB probiotics did produce significantly highest survival 13.83±0.76% over other LAB treatments. As a single isolates L. plantarum did produce survival 13.50±1.32% compared with those treated with L. salivarius and L. rhamnosus and those without probiotics (control. There was no statistical significance (p>0.05 in the survival of larvae in any treatment. Results indicate that LAB probiotics could be used to enhance survival of P. pelagicus larvae.

  1. The use of annual killifish in the biocontrol of the aquatic stages of mosquitoes in temporary bodies of fresh water; a potential new tool in vector control

    Directory of Open Access Journals (Sweden)

    Adrias Araceli Q

    2010-05-01

    Full Text Available Abstract Background Mosquitoes that breed in temporary pools in remote areas that dry up seasonally are especially difficult to control through chemical or biological means. The annual killifish has been suggested as a means of eradicating the aquatic stages of mosquitoes in transient pools because they can maintain permanent populations in such habitats by undergoing suspended animation or diapause during the embryonic stages to survive periodic drought. However, very little is known about the predatory activity of annual killifish and their usefulness in mosquito control. Results The annual killifish, Nothobranchius guentheri, native to Tanzania, was used in this investigation. Food preference was tested under laboratory conditions by feeding juvenile killifish with 2nd instar mosquito larvae of Culex quinquefasciatus in the presence of alternative food sources, such as rotifers and chironomid larvae. Semi-field tests were conducted by introduction of hibernating killifish embryos and juvenile fish to artificial ponds in an outdoor open environment that allowed natural oviposition of Cx. quinquefasciatus. Food preference studies show that N. guentheri preferred to prey on mosquito larvae than either chironomid or rotifers. When hibernating killifish embryos were added to ponds simultaneously with the addition of freshwater, the embryos hatched and fed on mosquito larval population resulting in complete elimination of the immature stages. The introduction of juvenile fish to ponds with high density of mosquito larvae resulted in total eradication of the mosquito population due to predation by fish. Complete biocontrol of the mosquito larval population was achieved in the presence of 3 fish per m2 of pond surface area. Conclusions The annual killifish provides yet another tool that may be employed in the eradication diseases carried by mosquitoes through vector control, particularly in temporary bodies of freshwater. The fish can be conveniently

  2. 秦皇岛海域"褐潮"海水对卤虫、轮虫存活和摄食的影响研究%Effect of "Brown Tide" onsurvival and ingestion of Artemia salina and Brachionus plicatilis in Qinhuangdao

    Institute of Scientific and Technical Information of China (English)

    公晗; 孔凡洲; 王云峰; 颜天; 周名江

    2015-01-01

    为评价秦皇岛褐潮现场海水的毒性, 作者利用HPLC技术及CHEMTAX, 分析了2013年7月2日采自秦皇岛褐潮高峰期微型及微微型浮游植物的色素组成及群落结构;测定了卤虫(Artemia salina)、轮虫(Brachionus plicatilis)存活率和摄食量.研究表明,褐潮海水微型及微微型浮游植物中,海金藻(Pelagophyceae)占主要优势,其生物量占总生物量的72.6%.褐潮海水抑制卤虫存活,卤虫48 h存活率降至77%;对轮虫24 h存活没有显著效应.此外,褐潮海水抑制卤虫、轮虫的摄食,卤虫、轮虫8 h内摄食量分别由(5.5±0.4)ng/个降至(2.4±0.4)ng/个、由(1.5±0.2)ng/个下降至(0.9±0.1)ng/个.该结果与美国的3株褐潮藻的毒性进行了比较.CCMP 1507对卤虫存活有显著抑制作用,其他两株没有显著效应; 3株褐潮藻对轮虫24 h存活都没有显著影响.暴露于3株褐潮藻中,卤虫的摄食量均显著较低;其中CCMP 1507在混合饵料中还抑制卤虫、轮虫对其他藻的摄食.对CCMP 1507各组分分析发现,该藻的毒性主要来源于藻细胞.结合现场试验与室内试验结果分析表明, 秦皇岛褐潮对卤虫、轮虫有一定的毒性,其毒性与CCMP 1507的毒性相当.%To studythe toxicity of the "Brown tide" in Qinhuangdao, the pigment profile and phytoplankton groups of the nano-sized and pico-sized phytoplankton samples collected from the "Brown tide" blooming sea area in Qinhuangdao on July 2rd, 2013 were analyzed using HPLC and CHEMTAX, and the survival and ingestion of Ar-temia salina and Brachionus plicatiliswere tested. It was found that pelagophytes played a predominant role, con-stituting 72.6% of the total phytoplankton biomass. The survival of A. salina decreased to 77% during 48 h expo-sure, while that of rotifer was not affected during 24 h exposure. Additionally, the ingestion of A. Salinaand rotifer in 8 hours was inhibited, reduced from (5.5±0.4)ng/ind to (2.4±0.4) ng/ind, and from (1.5±0.2) ng

  3. Spatio-temporal distribution characteristics of zooplankton and water quality assessment in middle and lower reaches of Ganjiang River%赣江中下游浮游动物时空分布特征及水质综合评价

    Institute of Scientific and Technical Information of China (English)

    计勇; 张洁; 孙晓秋; 麻夏

    2012-01-01

    对2010年12月与2011年7月赣江中下游各监测断面中浮游动物类群的结构组成、优势类群进行调查,结果表明:赣江中下游浮游动物有4类41种;种类最多的是轮虫类,共计7科15属25种,占总数的60.98%;枝角类5科6属7种,占17.07%;桡足类与原生动物占21.95%.时间分布上浮游动物丰度丰水期大于枯水期,密度变动范围为100~522个/L,其中丰水期轮虫、枝角类、桡足类与原生动物密度分别占浮游动物密度的61.7%,11.4%,18.9%与7.8%;枯水期轮虫、枝角类、桡足类与原生动物密度分别占浮游动物密度的65,3%,9.5%,16.0%与9.1%.浮游动物密度空间分布上呈现中间大、两端小的特点,最大值出现在4号监测点新干,最小值出现在10号监测点赣州.赣江中下游浮游动物数量结构主要由轮虫和桡足类组成,生物量结构则主要由桡足类和枝角类组成.生物多样性及水质综合评价为轻度污染至中度污染.%The population structure and dominant groups of zooplankton in the monitoring sections in the middle and lower reaches of the Ganjiang River were investigated in December of 2010 and July of 2011. The results show that there were 41 species of zooplankton, in which rotifers (seven families, 15 genera, and 25 species) , cladocerans (five families, six genera, and seven species) , and copepods and protozoa were predominant, respectively accounting for 60.98 % , 17.07% , and 21.95% of the total number. In regards to temporal distribution, the zooplankton abundance was greater in the wet season than in the dry season. The density of zooplankton ranged from 100 ind/L to 522 ind/L. The densities of rotifers, cladoeerans, copepods, and protozoa respectively accounted for 61.7% , 11.4%, 18.9%, and7.8% of the zooplankton density in the wet season, and 65.3% , 9.5% , 16.0% , and 9.1% of the zooplankton density in the dry season. It was found that the density of zooplankton was high

  4. Demography of zooplankton (Anuraeopsis fissa, Brachionus rubens and Moina macrocopa) fed Chlorella vulgaris and Scenedesmus acutus cultured on different media.

    Science.gov (United States)

    Morales-Ventura, Jesús; Nandini, S; Sarma, S S S; Castellanos-Páez, Maria Elena

    2012-09-01

    Generally zooplankton growth is often limited by the quality of their algal diet. A cheaper common practice in aquaculture, is to culture algae with fertilizers; however, the demography of zooplankton when fed these algae has not yet been evaluated. We studied the population growth and life table demography of the rotifers Anuraeopsis fissa and Brachionus rubens, and the cladoceran Moina macrocopa. For this, the algae Scenedesmus acutus or Chlorella vulgaris were cultured on defined (Bold's basal) medium or the commercial liquid fertilizer (Bayfolan). Experiments were conducted at one algal concentration 1.0 x 10(6) cells/mL of C. vulgaris or its equivalent dry weight of 0.5 x 10(6) cells/mL of S. acutus. The population dynamics were tested at 23 +/- 1 degrees C in 100 mL transparent jars, each with 50mL of the test medium, with an initial density of 0.5indiv/mL, for a total of 48 test jars (3 zooplankton 2 algal species x 2 culture media x 4 replicates). For the life table experiments with M. macrocopa, we introduced 10 neonates (<24h old) into each test jar containing the specific algal type and concentration. For the rotifer experiments, we set 5mL tubes with one neonate each and 10 replicates for each algal species and culture medium. We found that the average rotifer life span was not influenced by the diet, but for M. macrocopa fed S. acutus cultured in Bold's medium, the average lifespan was significantly lower than with the other diets. The gross and net reproductive rates of A. fissa (ranging from 18-36 offspring per female) were significantly higher for C vulgaris cultured in Bold medium. Regardless of the culture medium, Chlorella resulted in significantly higher gross and net reproductive rates for B. rubens than S. acutus diets. The reproductive rates of M. macrocopa were significantly higher in all the tested diets except when fed with S. acutus in Bold medium. The population increase rate, derived from growth experiments of A. fissa and B. rubens

  5. Characterization of biocenosis in the storage-reservoirs of liquid radioactive wastes of 'Mayak' PA

    Energy Technology Data Exchange (ETDEWEB)

    Pryakhin, E.; Tryapitsina, G.; Andreyev, S.; Akleyev, A. [Urals Research Center for Radiation Medicine - URCRM (Russian Federation); Mokrov, Y.; Ivanov, I. [Mayak PA (Russian Federation)

    2014-07-01

    cycle. In reservoir R-3 there was no small pelophylic mollusks either, 90% of zooplankton community was represented by rotifers, in zoo-benthos community there was no small pelophylic mollusks, in species composition of ichthyofauna there was no carnivorous species of fish. In reservoir R-17 ichthyofauna was completely absent, species diversity of phytoplankton was significantly reduced, zooplankton was represented only by rotifers, and zoo-benthos was represented only by gnat larvae. In reservoir R-9 there was no ichthyofauna; phytoplankton was almost a mono-culture of cyanobacteria Geitlerinema amphibium, zooplankton was almost a mono-culture of rotifers Brachionus calyciflorus or Hexartra fennic in different years. In all of the above mentioned reservoirs, the development of bacterial plankton was at the levels characteristic of the standing water bodies of this geographical zone. Document available in abstract form only. (authors)

  6. 大淀湖综合治理后浮游动物群落结构特征研究%Research on the community structure of zooplankton after comprehensive treatment in Lake Dadianhu,Shanghai

    Institute of Scientific and Technical Information of China (English)

    季高华; 张军毅; 王丽卿; 张瑞雷; 范志锋

    2011-01-01

    大淀湖于2005、2006年进行了清淤改造并采取了水体生态恢复措施。为评价水体生态整治效果,于2006年9月至2007年8月对大淀湖综合治理后浮游动物群落变化状况进行了逐月采样监测。结果共发现浮游动物72属149种,其中原生动物45属80种、轮虫20属61种、枝角类5属6种、桡足类2属2种。原生动物中优势属种为变形虫(Amoeba sp.)、球形砂壳虫(Difflugia globulosa)等,轮虫优势种为针簇多肢轮虫(Polyarthra trigla)、异尾轮虫(Trichocerca stylat%A comprehensive treatment was made in Lake Dadianhu(Shanghai) to desilt and restore ecological system during 2005 and 2006.A series of investigations on the dynamics of zooplankton community structure were made to evaluate the treatment from Sep.2006 to Aug.2007,monthly sampled.The investigations explored species diversity,density,biomass of zooplankton and the correlation between zooplankton and environmental facts.149 species of zooplankton were recorded including 80 species of Protozoa,61 species of Rotifer,2 species of Cladoceran and 2 species of Copepods.Amoeba sp.and DiffLugia globulosa were the dominant species of Protozoan while Polyarthra trigla and Trichocerca stylata were the dominant species of Rotifer.However,the dominant species changed in different seasons.The annual average density and biomass of zooplankton in Lake Dadianhu were 13.10×104 ind/L and 10.51 mg/L,respectively.The highest density and biomass emerged in spring(13.10×104 ind/L,10.51 mg/L).The highest proportion of density and highest proportion of biomass in the zooplankton community were both the proportion of Protozoan(98.02%,83.55%) and the second was the rotifer(1.99%,12.79%),Cladocera and Copeoda were low.The annual average density and biomass of Cladocera were 9.5 ind/L and 0.11 mg/L while the Copeoda were 0.32 ind/L and 0.01 mg/L.The average annual Shannon-Weiner index of Rotifer was 2.30 and Protozoan was 1

  7. EVALUACIÓN DE LA ROTIFEROFAUNA PRESENTE EN EL COMPLEJO DE PAJARALES DURANTE LA ÉPOCA LLUVIOSA, DEPARTAMENTO DE MAGDALENA, COLOMBIA Assessment Of The Pajarales Complex Rotiferofauna During The Rainy Season, Departamento De Magdalena, Colombia

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    SEBASTIÁN CELIS

    phylum, due to its high reproductive rates and the efficiency in energetic transformation process. We sampled the rotifers with a van Dorn bottle, during the second rainy season in 2006. During each sampling we registered salinity, temperature, pH, and dissolved oxygen. We calculated the rotifer diversity using the Shannon-Wiener H’ (log10 index comparing among sampling sites and sampling dates to establish variations along the study period. The physico-chemical variables were graphically related with the diversity values calculated using 0,05 for α and 95% for the confidence interval. We found a total of 20 morphotypes belonged to Brachionidae, Lecanidae, Filiniidae, Synchaetidae, Hexarthriidae and Testudinellidae families, been Brachionidae and Lecanidae the most abundant. The relationships between diversity and physico-chemical variables, show salinity as the main responsible of the rotifer diversity. In conclusion, the current rotiferofauna in the PC is most abundant and diverse than 16 years ago, before the recommunication with the Magdalena River. Likewise, dissolved oxygen concentration, pH and salinity of the CP waters were different. Taking into account that salinity was the most influent factor in the rotiferofauna diversity, the river recomommunication probably favored the increment of rotiferofauna diversity in the PC.

  8. Some aspects in early life stage of Siamese gourami, Trichogaster pectoralis (Regan Larvae

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    Ponpanom Promkaew

    2005-05-01

    post-hatching (just before the mouth opened. They were fed with rotifer at a density of 10 ind/ml. Twenty larvae were collected at random from the aquarium at 2-hourly intervals, preserved in 10% buffered formalin, and then dissected to determine the presence of rotifer in the digestive tract. The digestive tracts were fixed at 72 hr of hatching at water temperatures of 27.0-30.5ºC, and measured 503.73±22.57 μm in mouth height. The average number of rotifer in the digestive tract at the start of feeding was 0.57 individual/larva.A starvation experiment was carried out using a 15-liter glass aquarium (water volume 10 liters with three replications. Five hundred newly hatched larvae of Siamese gourami were kept without feeding. Larvae started to die at 72 hr and totally died within 156 hr after hatching at water temperature ranging between 27.0 and 30.5ºC.

  9. Spatial variations in the zooplankton community from the Corumbá Reservoir, Goiás State, in distinct hydrological periods = Variações espaciais da comunidade zooplanctônica no reservatório de Corumbá (Estado de Goiás, em distintos períodos hidrológicos

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    Erica Mayumi Takahashi

    2009-07-01

    Full Text Available This study evaluated the spatial variations in species richness and abundance of zooplankton over a hydrological cycle, and also verified the influence of physical and chemical water variables and chlorophyll-a concentrations on the abundance of these organisms. The tested hypothesis was that the zooplankton community presents higherspecies richness in lotic environments and higher abundance in lentic ones. One hundred forty species were identified, distributed among rotifers (88, testate amoebae (35, cladocerans (13 and copepods (4. Higher values of species richness and abundance were observed during the dry period. During both hydrological periods, the copepods presented high abundance values, due to the contribution of young stages, followed by rotifers, cladocerans and testate amoebae. In general, testate amoebae presented high values of species richness and abundance in lotic sampling stations, whereas the other zooplankton groups (rotifers, cladocerans and copepods presented higher abundances in lentic environments and higher species richness in lotic ones. The Pearson correlation analysis evidenced the importance of physical and chemical water variables and food resourceavailability influencing the variation of organisms’ abundance.O objetivo deste estudo foi avaliar as variações espaciais da riqueza e abundância do zooplâncton ao longo de um ciclo hidrológico, bem como verificar a influência das variáveis físicas e químicas da água e concentrações de clorofila-a sobre a abundância desses organismos. Pressupõe-se que a comunidade zooplanctônica apresente maior riqueza de espécies em ambientes lóticos e maior abundância em ambientes lênticos. Foram identificadas 140 espécies, sendo 88 de rotíferos, 35 de amebas testáceas, 13 de cladóceros e quatro de copépodes. Os maiores valores de riqueza e abundância foram verificados no período de estiagem. Em ambos os períodos hidrológicos, os copépodes apresentaram

  10. Characterization of biocenosis in the storage-reservoirs of liquid radioactive wastes of 'Mayak' PA

    International Nuclear Information System (INIS)

    small pelophylic mollusks either, 90% of zooplankton community was represented by rotifers, in zoo-benthos community there was no small pelophylic mollusks, in species composition of ichthyofauna there was no carnivorous species of fish. In reservoir R-17 ichthyofauna was completely absent, species diversity of phytoplankton was significantly reduced, zooplankton was represented only by rotifers, and zoo-benthos was represented only by gnat larvae. In reservoir R-9 there was no ichthyofauna; phytoplankton was almost a mono-culture of cyanobacteria Geitlerinema amphibium, zooplankton was almost a mono-culture of rotifers Brachionus calyciflorus or Hexartra fennic in different years. In all of the above mentioned reservoirs, the development of bacterial plankton was at the levels characteristic of the standing water bodies of this geographical zone. Document available in abstract form only. (authors)

  11. Effects of diets on growth and survival rates of Octopus vulgaris paralarvae%不同饵料对真蛸浮游幼体生长和存活的影响

    Institute of Scientific and Technical Information of China (English)

    李雷斌; 钟建兴; 宁岳; 刘波; 曾武斌

    2012-01-01

    为了满足真蛸浮游幼体阶段的营养需要,研究了几种饵料生物对真蛸浮游幼体的育苗效果。结果表明:轮虫不宜作为真蛸浮游幼体的生物饵料;恒温培养试验得出混合营养强化的丰年虫幼体的育苗效果优于混合营养强化的蒙古裸腹溞,并优于小球藻强化的丰年虫幼体及蒙古裸腹溞;常温试验得出梭子蟹溞状幼体+丰年虫幼体组合的饵料效果最好,而微囊营养强化剂强化的丰年虫幼体的育苗效果好于混合营养组合。综上所述,可认为:梭子蟹溞状幼体+丰年虫幼体组合是真蛸浮游幼体期比较适宜的饵料。%Growth and survival rates of Octopus vulgaris paralarvae feeding on rotifers, enriched anaemia nauplii, enriched Moina mongolica, Daphnia - like larvae of Ponaunus trituberculatus were tested. The result showed that rotifer was not appropriate for Octopus vulgaris paralarvae as diet; the effect sequence of diets on growth and survival rates of octopus vulgaris paralarvae in constant temperature test was mix enriched anaemia nauplii 〉 mix enriched Moina mongolica 〉 anaemia nauplii enriched by Chlorella 〉 Moina mongolica enriched by Chlorella; the effect sequence of diets on growth and survival rates of octopus vulgaris paralarvae at room temperature test was daphnia - like larvae of Ponaunus trituberculatu + anaemia nauplii 〉 anaemia nauplii enriched by fish oil 〉 mix enriched anaemia nauplii. It may be considered that the "daphnia - like larvae of Portunus trituberculatu + anaemia nauplii" was the better food for the paralarvae of Octopus vulgaris.

  12. Estudo comparativo da composição do zooplâncton de dois ecossistemas lacustres da Amazônia Sul-Ocidental - DOI: 10.4025/actascibiolsci.v25i2.2042 Comparative study of the zooplankton composition of two lacustrine ecosystems in Southwestern Amazonia

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    Erlei Cassiano Keppeler

    2003-04-01

    Full Text Available A comunidade zooplanctônica de dois ecossistemas lacustres localizados na Amazônia Sul-Ocidental (Lago Amapá e Lago Pirapora foi estudada, com base em amostras coletadas, durante 11 meses. O objetivo geral do presente trabalho foi contribuir com o conhecimento da fauna do zooplâncton na Amazônia Sul-Ocidental, estudando particularmente a ocorrência de certas espécies nos tributários do Rio Acre. Foi registrado o total de taxas: 38 rotíferos, 6 cladóceros e 7 copépodos. O índice de Jaccard, para comparar a similaridade entre os dois lagos, foi 0,6964. Brachionidae foi a família com o maior número de espécies. O índice de constância definiu as espécies Keratella cochlearis, Filinia cf. terminalis, Filinia opoliensis, Hexarthra intermedia braziliensis, Ceriodaphnia cornuta, Moina minuta, Diaphanosoma spinulosum, e ainda as formas imaturas (náuplios e copepoditos como constantes nos lagos estudados. Observou-se o maior número de espécies ocupando o meio da coluna da água, durante o período da manhã e noiteThe zooplankton communities of two lacustrine ecosystems in southwestern Amazonia (Lago Amapá and Lago Pirapora were studied based on samples collected over an 11-month period. The general aim of the present work was to contribute to the knowledge of the zooplankton fauna in southwestern Amazonia, by studying the occurrence of certain species; and to improve the knowledge of the Rio Acre tributaries. The total number of taxa included 38 species of rotifers, 6 cladocerans and 7 copepods. Most of the species were from the rotifer family Brachionidae. Jaccard´s similarity index was similar for the two lakes at 0.6964 The constancy index defined the species Keratella cochlearis, Filinia cf. terminalis, Filinia opoliensis, Hexarthra intermedia braziliensis, Ceriodaphnia cornuta, Moina minuta, Diaphanosoma spinulosum, and immature forms (nauplii and copepodites as the constant in these lakes. The presence of zooplankton with

  13. Zooplankton abundance, species composition and ecology of tropical high-mountain crater lake Wonchi, Ethiopia

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    Fasil Degefu

    2014-11-01

    Full Text Available The highlands of Ethiopia represent some of the remnants of undisturbed aquatic ecosystems; they are however highly threatened by significant socio–economic developments and associated anthropogenic impacts. Lake Wonchi is one of the few remaining fairly pristine high–mountain crater lakes in the central highlands and has never been investigated in detail. We present a first study on zooplankton taxa composition, abundance and biomass conducted over more than one year including the underlying environmental drivers. The lake is basic (pH 7.9-8.9, dilute (specific conductivity 185-245 µS cm-1 and oligotrophic with mean trophic status index of 36. The zooplankton community composition showed low species richness comprising a total of fourteen taxa with six cladocerans, one copepod and seven rotifers. Simpson´s index of diversity with values between 0.6 and 0.8 pointed towards a homogenous taxa occurrence within the single sample units. The overall mean (±SD standing biomass of zooplankton was 62.02±25.76 mg dry mass m-3,which is low compared to other highland and rift valley lakes in Ethiopia. Cyclopoid copepods, in particular Thermocyclops ethiopiensis were the most abundant group and contributed 50% to the total zooplankton abundance followed by cladocerans (38% and rotifers (12%. Non-metric multi-dimensional scaling resulted in a 3-dimensional model, which revealed similar community composition on successive sampling dates except in December/January and May. Temperature, alkalinity, conductivity and nitrate-N had significant influence on this seasonal pattern. A weak, but significant positive correlation (r=0.482, N=20, P=0.037 between Chlorophyll a and zooplankton biomass mirrors a bottom-up effect of phytoplankton biomass on zooplankton dynamics. The zooplankton of Lake Wonchi displayed some degree of segregation along the epi– and metalimnion during this study, but diel vertical migration was not observed. The results show that fish

  14. 沼液珍珠养殖高值资源化利用%High Value and Resourceful Utilization of Biogas Slurry Resources for Pearl Culture

    Institute of Scientific and Technical Information of China (English)

    单胜道; 王志荣; 宋成芳

    2012-01-01

    The effects of biogas slurry fertilizers on pearl culture, including pearl survival rate, pearl food concentration and pearl yield and quality were studied. The results showed that, by biogas slurry cultures, the death rate of pearl mussel mortality declined by 7%, the population of beneficial algae and rotifer increased in breeding waters, and the rotifer concentration was 556 times that of the original. The results also showed that pearl yield and quality had been improved to different extents, the yield increased by 6% , the output rate of round pearl increased by 1.5% ,the high quality pearl rate can be increased by 8% and the gloss level A + B pearl proportion increased by 1%. Thus method of biogas slurry cultured pearl is not only a way for effective use of hiogas slurry, but also can reduce their emissions to bring water environment problem.%以沼液为肥料,研究其对珍珠存活率、珍珠食物浓度及珍珠产量和品质等的影响.结果表明:沼液养殖珍珠,使得珍珠蚌的死亡率下降7%;养殖水域中有益藻类和轮虫的数量显著增加,其中轮虫的浓度为原来的556倍;珍珠的产量和品质也有不同程度提高,其中产量提高了6%,圆珠产出率提高1.5%,优质珠率提高8%,光泽度A+B级的珍珠比例增加7%.因此,沼液养殖珍珠是沼液有效利用的一种途径,同时还可减少其排放带来的水环境问题.

  15. Microbial community variation and functions to excess sludge reduction in a novel gravel contact oxidation reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lin Shanshan; Jin, Y.; Fu, L. [School of Urban and Environmental Science, Northeast Normal University, Changchun (China); Quan, C. [Jilin University, College of medicine, Changchun (China); Yang, Y.S., E-mail: yangy6@cf.ac.uk [Cardiff University, School of Earth and Ocean Sciences, Cardiff CF10 3YE (United Kingdom)

    2009-06-15

    both in GCOR (15 no. per 20 ml) and in ASR (15 no. per 20 ml); the next abundant group was attachment plants 10 no. per 20 ml in GCOR and 4 no. per 20 ml in ASR, respectively. Rotifers and copepoda belonging to metazoan were only present in GCOR (8 no. per 20 ml for both rotifers and copepoda). The microbial diversity and population difference both in the GCOR carriers and ASR sludge indicated that the diverse microbes, a large amount of biomass forming longer microbial food chains attached on the carriers may be the main functions for the excess sludge reduction in GCOR.

  16. Distribution and abundance of zooplankton populations in Crater Lake, Oregon

    Science.gov (United States)

    Larson, G.L.; McIntire, C.D.; Buktenica, M.W.; Girdner, S.F.; Truitt, R.E.

    2007-01-01

    The zooplankton assemblages in Crater Lake exhibited consistency in species richness and general taxonomic composition, but varied in density and biomass during the period between 1988 and 2000. Collectively, the assemblages included 2 cladoceran taxa and 10 rotifer taxa (excluding rare taxa). Vertical habitat partitioning of the water column to a depth of 200 m was observed for most species with similar food habits and/or feeding mechanisms. No congeneric replacement was observed. The dominant species in the assemblages were variable, switching primarily between periods of dominance of Polyarthra-Keratella cochlearis and Daphnia. The unexpected occurrence and dominance of Asplanchna in 1991 and 1992 resulted in a major change in this typical temporal shift between Polyarthra-K. cochlearis and Daphnia. Following a collapse of the zooplankton biomass in 1993 that was probably caused by predation from Asplanchna, Kellicottia dominated the zooplankton assemblage biomass between 1994 and 1997. The decline in biomass of Kellicottia by 1998 coincided with a dramatic increase in Daphnia biomass. When Daphnia biomass declined by 2000, Keratella biomass increased again. Thus, by 1998 the assemblage returned to the typical shift between Keratella-Polyarthra and Daphnia. Although these observations provided considerable insight about the interannual variability of the zooplankton assemblages in Crater Lake, little was discovered about mechanisms behind the variability. When abundant, kokanee salmon may have played an important role in the disappearance of Daphnia in 1990 and 2000 either through predation, inducing diapause, or both. ?? 2007 Springer Science+Business Media B.V.

  17. Seasonal dynamics of zooplankton in Columbia–Snake River reservoirs,with special emphasis on the invasive copepod Pseudodiaptomus forbesi

    Science.gov (United States)

    Emerson, Joshua E; Bollens, Stephen M; Counihan, Timothy D.

    2014-01-01

    The Asian copepod Pseudodiaptomus forbesi has recently become established in the Columbia River. However, little is known about its ecology and effects on invaded ecosystems. We undertook a 2-year (July 2009 to June 2011) field study of the mesozooplankton in four reservoirs in the Columbia and Snake Rivers, with emphasis on the relation of the seasonal variation in distribution and abundance of P. forbesi to environmental variables. Pseudodiaptomus forbesi was abundant in three reservoirs; the zooplankton community of the fourth reservoir contained no known non-indigenous taxa. The composition and seasonal succession of zooplankton were similar in the three invaded reservoirs: a bloom of rotifers occurred in spring, native cyclopoid and cladoceran species peaked in abundance in summer, and P. forbesi was most abundant in late summer and autumn. In the uninvaded reservoir, total zooplankton abundance was very low year-round. Multivariate ordination indicated that temperature and dissolved oxygen were strongly associated with zooplankton community structure, with P. forbesi appearing to exhibit a single generation per year . The broad distribution and high abundance of P. forbesi in the Columbia–Snake River System could result in ecosystem level effects in areas intensively managed to improve conditions for salmon and other commercially and culturally important fish species. 

  18. Passive zooplankton community in different environments of a neotropical floodplain - doi: 10.4025/actascibiolsci.v34i4.11161

    Directory of Open Access Journals (Sweden)

    Claudia Costa Bonecker

    2012-09-01

    Full Text Available Zooplankton is able to respond promptly to environmental changes, producing resting forms in order to maintain populations when the conditions become unfavorable. The hatchling of the resting eggs was assessed in environments from the upper Paraná river floodplain, during the limnophase of 2008. We predicted that a higher production of these eggs and individuals’ hatchling are observed at isolated lakes, during dried period. Sediment samples were obtained with a corer sampler. The resting eggs were sorted and kept in filtered water from the same environment, in the laboratory. We recorded the occurrence of 378 resting eggs, of which 122 individuals hatched (70 cladocerans and 52 rotifers. The highest number of hatchlings was verified for the isolated lakes (84 individuals, as well the shorter time for hatchling (2 days. The hatchlings occurred mainly in September, when we registered the lowest hydrologic level of Paraná river (2.40 m. Grimaldina brazzai presented the longest time for hatchling, 44 days; and Brachionus dolabratus and B. falcatus, the shortest time, 2 days. This result suggests that the longer residence time of the water, which did not allow a renewal of food resources and limnological conditions of the environment, caused a higher stress in the zooplankton.  

  19. The Effects of Petroleum Hydrocarbons on Algae Can Be Reversed in the Presence of a Primary Consumer.

    Science.gov (United States)

    Wang, Changyou; Zhang, Yong; Li, Hongli; Xing, Wenhui; Yu, Hua

    2015-09-01

    The ecotoxicological effects of a mixture of petroleum hydrocarbons were tested on densities of two algae, Platymonas helgolandica var. tsingtaoensis and Isochrysis galbana, and of a rotifer, Brachionus plicatilis, by single-species and customized community experiments. Test concentrations ranged from 0 to 100 mg L(-1), while five to seven treatments were assessed in triplicate within 1 month. A significant decrease in densities during single-species toxicity tests were found when concentrations of petroleum hydrocarbons were above 1.0 mg L(-1). However, equilibrium densities of algae in the customized community showed a different pattern, which increased with concentration and reached a peak at 20.0 mg L(-1). The community-based no observed effect concentration (NOEC; 1.0 mg L(-1)) was different from the NOEC derived by single-species toxic tests (0.25 mg L(-1)). This demonstrates that ecotoxicological effects on plankton as part of a community is significantly different from single-species toxicity tests owing to ecological interactions.

  20. Shifts in microbial community structure and function in light- and dark-grown biofilms driven by warming.

    Science.gov (United States)

    Romaní, Anna M; Borrego, Carles M; Díaz-Villanueva, Verónica; Freixa, Anna; Gich, Frederic; Ylla, Irene

    2014-08-01

    Biofilms are dynamic players in biogeochemical cycling in running waters and are subjected to environmental stressors like those provoked by climate change. We investigated whether a 2°C increase in flowing water would affect prokaryotic community composition and heterotrophic metabolic activities of biofilms grown under light or dark conditions. Neither light nor temperature treatments were relevant for selecting a specific bacterial community at initial phases (7-day-old biofilms), but both variables affected the composition and function of mature biofilms (28-day-old). In dark-grown biofilms, changes in the prokaryotic community composition due to warming were mainly related to rotifer grazing, but no significant changes were observed in functional fingerprints. In light-grown biofilms, warming also affected protozoan densities, but its effect on prokaryotic density and composition was less evident. In contrast, heterotrophic metabolic activities in light-grown biofilms under warming showed a decrease in the functional diversity towards a specialized use of several carbohydrates. Results suggest that prokaryotes are functionally redundant in dark biofilms but functionally plastic in light biofilms. The more complex and self-serving light-grown biofilm determines a more buffered response to temperature than dark-grown biofilms. Despite the moderate increase in temperature of only 2°C, warming conditions drive significant changes in freshwater biofilms, which responded by finely tuning a complex network of interactions among microbial populations within the biofilm matrix.

  1. Development of Enzymes and In Vitro Digestibility during Metamorphosis and Molting of Blue Swimming Crab (Portunus pelagicus

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    Phanu Chamchuen

    2014-01-01

    Full Text Available The work focuses on development of digestive enzymes (amylase, total protease, trypsin, and chymotrypsin and activity ratio of trypsin to chymotrypsin (T/C ratio for digestive efficiency and growth, in blue swimming crab (Portunus pelagicus during metamorphosis and molting. Specific activities of all enzyme parameters studied were associated with growth during metamorphosis, while only those of trypsin and T/C ratio were associated during molting cycle where trypsin and chymotrypsin specific activities associated with consumption rate with especially high levels during late intermolt and early premolt stages. About 50% increased weight gain was observed with at least double increased T/C ratio at the end of molting period, compared to the stages prior to molting. Growth of carapace would be more significant after finishing molting. Carapace width gain and T/C ratio were highest at the first crab stage. Studies of in vitro protein digestibility of different feed raw materials indicated that Artemia, Rotifer, and Moina are the best for larval stages. Otherwise, the use of shrimp feed and Artemia flake could be the alternatives. Incorporating of cassava meal into the feed formula for early adult stage (juvenile could be an advantage. The proteins from animals are more beneficial for adult crab culture than the proteins from plants and bacteria. The digestible quality of dietary protein is very important during larval stages, while the protein level of diet is more important during adult stages with fully developed digestive enzymes.

  2. Nutritional requirements of freshwater ornamental fish: a review

    Directory of Open Access Journals (Sweden)

    Yohana Velasco-Santamaría

    2011-05-01

    Full Text Available The knowledge of nutritional requirements in ornamental fish species is essential to improve the productive development; however, the nutritional information of these species is scarce and sometimes this information is extrapolated from results obtained from non-ornamental fish species. In ornamental fish, a correct formulation of the diet improve the nutrient digestibility and supply the metabolic needs, reducing the maintenance cost and at the same time the water pollution. Inert food such as meal powder, flakes, milk powder, bovine heart and liver, tubifex worms, as well as live food including Artemia sp., rotifers and Moina have been used extensively in ornamental fish feeding with a diverse range of nutritional values and productive properties. In contrast with farmed fish, skin pigmentation is a mandatory characteristic in ornamental fish and the use of dietary supplements with carotenoids is recommended. The aim of this document is to review the specific nutritional requirements which are indispensable to improve economical and productive potential of freshwater ornamental fish.

  3. Composition, diversity and short-term temporal fluctuations of zooplankton communities in fish culture ponds (Pindamonhangaba), SP.

    Science.gov (United States)

    Negreiros, N F; Rojas, N E; Rocha, O; Santos Wisniewski, M J

    2009-08-01

    The present study aimed at evaluating the composition, diversity and short-term temporal fluctuations of zooplankton communities in fish ponds. The study was carried out in two fish ponds, with 180 m(2) of water surface (6 x 30 m) each, located in the Aquiculture Centre of the Pindamonhangaba Fisheries Institute - São Paulo. The study was developed over eight weeks, from February 16 to April 6, 1998. The physical and chemical conditions of the water in the fish ponds were adequate for zooplankton development. The zooplanktonic community was characterised by high richness of species and a greater diversity was observed in the first fish pond, with a superior density of Rotifera. Temporal changes in zooplankton composition occurred in both ponds with Cladocera appearing in abundance later, in the fourth week, whereas copepods and rotifers were well represented since the beginning. Many species found are typical of fish ponds and are considered to constitute an excellent food source, showing high nutritional value for fish larvae, a good example being individuals from the Rotifera group and the micro-crustacean species Moina minuta and Thermocyclops decipiens. PMID:19802437

  4. Microcrustacea in flowing water - experimental-analysis of washout times and a field-test

    Science.gov (United States)

    Richardson, W.B.

    1992-01-01

    1. Flow-chamber experiments were conducted to evaluate the ability of microcrustacea to maintain position in moving water. These results were compared to distributions of zooplankton and water velocity in a stream pool to determine the relationship of animal density to water movement and swimming ability.^2. Cladocerans exhibited negative rheotaxis (directed behaviour against a current) but poor ability to maintain position at velocities >2.5 Cm s-1. Daphnia and scapholeberis were better at avoiding washout than moina and diaphanosoma. At velocities 2.5 Cm s-1, scapholeberis >3.2 Cm s-1 and eucyclops >7.75 Cm s-1. Washout time of daphnia and scapholeberis was positively related to body size and negatively to water velocity and possession of eggs. Washout was inversely related to water velocity for eucyclops.^4. Highest densities of microcrustacea in a stream pool were found in non-flowing or downstream zones of the pool. Benthic (hydracarina, harpacticoid copepods, ostracods) and fast-swimming (cyclopoids) forms were most common in flowing zones. Facultatively benthic cladocera were abundant in regions of no flow. Rotifers and immature copepods were most abundant at the downstream end of the pool.^5. Behavioural mechanisms for remaining in stream pools at times of high flow appear to include: (i) flow avoidance (simocephalus, chydorus, scapholeberis and cyclopoids), (ii) use of benthic habitat (ostracods, harpacticoids, hydracarina), (iii) strong swimming ability (cyclopoids).

  5. Predation on Mosquito Larvae by Mesocyclops thermocyclopoides (Copepoda: Cyclopoida) in the Presence of Alternate Prey

    Science.gov (United States)

    Kumar, Ram; Ramakrishna Rao, T.

    2003-11-01

    The cyclopoid copepod Mesocyclops thermocyclopoides, a dominant invertebrate predator in many shallow ponds and temporary water bodies in northern India, feeds on cladocerans, rotifers, ciliates and when present, on mosquito larvae also. We studied in the laboratory the prey consumption rates of the copepod on first and fourth instar larvae of two species of mosquito (Anopheles stephensi and Culex quinquefasciatus) in relation to their density. We also studied its prey selectivity with mosquito larvae in the presence of an alternate prey (the cladocerans-either Moina macrocopa or Ceriodaphnia cornuta) in different proportions. With either mosquito species, the copepod actively selected Instar-I larvae, avoiding the Instar-IV larvae, and with either instar, selected Anopheles stephensi over Culex quinquefasciatus. When prey choice included the cladoceran as an alternate prey, the copepod selected the cladoceran only when the other prey was Instar-IV mosquito larvae. Our results point to the potential and promise of M. thermocyclopoides as a biological agent for controlling larval populations of vectorially important mosquito species.

  6. Survival Rate and Development Period of the Larvae of Portunus pelagicus (Decapoda, Brachyura, Portunidae In Relation to Temperature and Salinity

    Directory of Open Access Journals (Sweden)

    R Ravi

    2012-01-01

    Full Text Available Berried females of Portunus pelagicus (Blue swimmer crab were collected from the wild and the zoea 1 obtained from a single berry were stocked in 200 litre tanks at the rate of 25 numbers/mL. In order to study the independent effects of temperature and salinity, the larvae were reared in three different temperatures (26°C, 28°C and 30°C at a fixed salinity of 35 ppt and in three different salinities (25 ppt, 30 ppt and 35 ppt at a fixed temperature of 28°C. Feeding was carried outwith microalgae, rotifers, moina and formulated shrimp feed, which varied with stage. The survival rates at each stage in all the trials were assessed by random sampling. The most ideal temperature and salinity among those studied were calculated in relation to the overall survival rate and larval development period. The data pertaining to both temperature and salinity manipulated investigations were found to be significant (P < 0.01 when subjected to one-way ANOVA. Among the tested temperatures, the highest average survival (14.12  0.31% and the lowest average development period (14.67 days were obtained at 30 ± 0.1°C. Among the salinity values tested, the highest mean survival rate (06.89 ± 0.06% and the lowest average development period (14.33 days were obtained at 35 ppt.

  7. Captive propagation, reproductive biology, and early life history of the Diamond Darter (Crystallaria cincotta)

    Science.gov (United States)

    Ruble, Crystal L.; Rakes, Patrick L.; Shute, John R.; Welsh, Stuart

    2014-01-01

    Reproductive biology and early life history data are critical for the conservation and management of rare fishes. During 2008–2012 a captive propagation study was conducted on the Diamond Darter, Crystallaria cincotta, a rare species with a single extant population in the lower Elk River, West Virginia. Water temperatures during spawning ranged from 11.1–23.3 C. Females and males spawned with quick vibrations, burying eggs in fine sand in relatively swift clean depositional areas. Egg size was 1.8–1.9 mm, and embryos developed within 7 to 11 d. Diamond Darters were 6.7–7.2 mm total length (TL) at hatch. Larvae ranged from 9.0–11.0 mm TL following a 5–10 d period of yolk sac absorption. Larvae had relatively large mouth gapes and teeth and were provided brine shrimp Artemia sp., Ceriodaphnia dubia neonates, marine Brachionus rotifers, and powdered foods (50–400 µm) but did not appear to feed in captivity, except for one observation of larval cannibalization. Larvae survived for a maximum of 10 d. To increase larval survival and reduce the possibility of cannibalism, other alternative food sources are needed during captive propagation.

  8. Rapid contemporary evolution and clonal food web dynamics.

    Science.gov (United States)

    Jones, Laura E; Becks, Lutz; Ellner, Stephen P; Hairston, Nelson G; Yoshida, Takehito; Fussmann, Gregor F

    2009-06-12

    Character evolution that affects ecological community interactions often occurs contemporaneously with temporal changes in population size, potentially altering the very nature of those dynamics. Such eco-evolutionary processes may be most readily explored in systems with short generations and simple genetics. Asexual and cyclically parthenogenetic organisms such as microalgae, cladocerans and rotifers, which frequently dominate freshwater plankton communities, meet these requirements. Multiple clonal lines can coexist within each species over extended periods, until either fixation occurs or a sexual phase reshuffles the genetic material. When clones differ in traits affecting interspecific interactions, within-species clonal dynamics can have major effects on the population dynamics. We first consider a simple predator-prey system with two prey genotypes, parametrized with data from a well-studied experimental system, and explore how the extent of differences in defence against predation within the prey population determine dynamic stability versus instability of the system. We then explore how increased potential for evolution affects the community dynamics in a more general community model with multiple predator and multiple prey genotypes. These examples illustrate how microevolutionary 'details' that enhance or limit the potential for heritable phenotypic change can have significant effects on contemporaneous community-level dynamics and the persistence and coexistence of species.

  9. Protection of waterborne pathogens by higher organisms in drinking water: a review.

    Science.gov (United States)

    Bichai, Françoise; Payment, Pierre; Barbeau, Benoit

    2008-07-01

    Higher organisms are ubiquitous in surface waters, and some species can proliferate in granular filters of water treatment plants and colonize distribution systems. Meanwhile, some waterborne pathogens are known to maintain viability inside amoebae or nematodes. The well-documented case of Legionella replication within amoebae is only one example of a bacterial pathogen that can be amplified inside the vacuoles of protozoa and then benefit from the protection of a resistant structure that favours its transport and persistence through water systems. Yet the role of most zooplankton organisms (rotifers, copepods, cladocerans) in pathogen transmission through drinking water remains poorly understood, since their capacity to digest waterborne pathogens has not been well characterized to date. This review aims at (i) evaluating the scientific observations of diverse associations between superior organisms and pathogenic microorganisms in a drinking water perspective and (ii) identifying the missing data that impede the establishment of cause-and-effect relationships that would permit a better appreciation of the sanitary risk arising from such associations. Additional studies are needed to (i) document the occurrence of invertebrate-associated pathogens in relevant field conditions, such as distribution systems; (ii) assess the fate of microorganisms ingested by higher organisms in terms of viability and (or) infectivity; and (iii) study the impact of internalization by zooplankton on pathogen resistance to water disinfection processes, including advanced treatments such as UV disinfection.

  10. The use of morphological and histological features as nutritional condition indices of Pagrus pagrus larvae

    Directory of Open Access Journals (Sweden)

    Marina Vera Diaz

    2013-09-01

    Full Text Available Morphometrical and histological techniques were employed to characterize Pagrus pagrus larvae nutritional condition. Larvae were reared in laboratory under controlled conditions with the main objective of testing whether these methodologies allowed finding differences between larvae from different feeding treatments. Once yolk was consumed (three days after hatching larvae were assigned to a feeding treatment: starved during the whole experiment; delayed feeding, starved during three days; fed during the entire experiment. Algae (Nannochloropsis oculata and rotifers (Brachionus plicatilis were provided to larvae for feed treatments. Larvae were fixed daily; for morphometrical purposes in 5% formaldehyde solution, and in Bouin for histological sections. Results herein obtained showed that both methodologies are sensitive enough to distinguish larvae characterized by different nutritional condition states obtained from the feeding treatments. Consequently, these methodologies could be employed in wild red porgy larvae in order to asses their nutritional condition. These techniques could also be employed to check larval quality obtained with aquaculture purposes to estimate the effects of changes in rearing protocols or kind of food supply and thus, to guaranty a higher survival of early developmental stages of reared larvae.

  11. Isolation and Characterization of Two Lytic Bacteriophages, φSt2 and φGrn1; Phage Therapy Application for Biological Control of Vibrio alginolyticus in Aquaculture Live Feeds.

    Directory of Open Access Journals (Sweden)

    Panos G Kalatzis

    Full Text Available Bacterial infections are a serious problem in aquaculture since they can result in massive mortalities in farmed fish and invertebrates. Vibriosis is one of the most common diseases in marine aquaculture hatcheries and its causative agents are bacteria of the genus Vibrio mostly entering larval rearing water through live feeds, such as Artemia and rotifers. The pathogenic Vibrio alginolyticus strain V1, isolated during a vibriosis outbreak in cultured seabream, Sparus aurata, was used as host to isolate and characterize the two novel bacteriophages φSt2 and φGrn1 for phage therapy application. In vitro cell lysis experiments were performed against the bacterial host V. alginolyticus strain V1 but also against 12 presumptive Vibrio strains originating from live prey Artemia salina cultures indicating the strong lytic efficacy of the 2 phages. In vivo administration of the phage cocktail, φSt2 and φGrn1, at MOI = 100 directly on live prey A. salina cultures, led to a 93% decrease of presumptive Vibrio population after 4 h of treatment. Current study suggests that administration of φSt2 and φGrn1 to live preys could selectively reduce Vibrio load in fish hatcheries. Innovative and environmental friendly solutions against bacterial diseases are more than necessary and phage therapy is one of them.

  12. Isolation and Characterization of Two Lytic Bacteriophages, φSt2 and φGrn1; Phage Therapy Application for Biological Control of Vibrio alginolyticus in Aquaculture Live Feeds.

    Science.gov (United States)

    Kalatzis, Panos G; Bastías, Roberto; Kokkari, Constantina; Katharios, Pantelis

    2016-01-01

    Bacterial infections are a serious problem in aquaculture since they can result in massive mortalities in farmed fish and invertebrates. Vibriosis is one of the most common diseases in marine aquaculture hatcheries and its causative agents are bacteria of the genus Vibrio mostly entering larval rearing water through live feeds, such as Artemia and rotifers. The pathogenic Vibrio alginolyticus strain V1, isolated during a vibriosis outbreak in cultured seabream, Sparus aurata, was used as host to isolate and characterize the two novel bacteriophages φSt2 and φGrn1 for phage therapy application. In vitro cell lysis experiments were performed against the bacterial host V. alginolyticus strain V1 but also against 12 presumptive Vibrio strains originating from live prey Artemia salina cultures indicating the strong lytic efficacy of the 2 phages. In vivo administration of the phage cocktail, φSt2 and φGrn1, at MOI = 100 directly on live prey A. salina cultures, led to a 93% decrease of presumptive Vibrio population after 4 h of treatment. Current study suggests that administration of φSt2 and φGrn1 to live preys could selectively reduce Vibrio load in fish hatcheries. Innovative and environmental friendly solutions against bacterial diseases are more than necessary and phage therapy is one of them.

  13. Zooplankton diversity and distribution in a deep and anoxic Mediterranean coastal lake

    Directory of Open Access Journals (Sweden)

    G. KEHAYIAS

    2013-04-01

    Full Text Available The variation of the smaller size fraction of zooplankton was investigated during a two-year period in a brackish deep and anoxic coastal lake of western Greece (Aitoliko, along with the specific environmental characteristics of this ecosystem. The zooplanktonic community comprised a relatively small number of taxa and it was dominated by brackish-water calanoid copepods (Paracartia latisetosa, Calanipeda aquaedulcis and in certain periods by rotifers and tintinnids. The zooplankton abundance showed an increase in the warmer period starting from late spring and reached maximum values in July. In the well oxygenated surface layer, temperature was the most important parameter influencing the seasonal cycles of all groups. In contrast, the oxygen depletion a few meters under the surface affected the vertical distribution of most of the zooplankton groups, which were found restricted in the surface layer especially from spring until autumn. Only the meroplanktonic larvae of polychaetes presented increased proportions in the deeper layers. Salinity has not significantly influenced the zooplanktonic assemblages. The results point out the degraded status of the Aitoliko basin where the hypoxic/anoxic layers resulted to a high portion of dead organic material identified as copepod carcasses, and underlines the necessity of monitoring of this ecosystem.

  14. Eukaryotic Organisms in Extreme Acidic Environments, the Río Tinto Case

    Science.gov (United States)

    Angeles Aguilera, Angeles

    2013-07-01

    A major issue in microbial ecology is to identify the limits of life for growth and survival, and to understand the molecular mechanisms that define these limits. Thus, interest in the biodiversity and ecology of extreme environments has grown in recent years for several reasons. Some are basic and revolve around the idea that extreme environments are believed to reflect early Earth conditions. Others are related to the biotechnological potential of extremophiles. In this regard, the study of extremely acidic environments has become increasingly important since environmental acidity is often caused by microbial activity. Highly acidic environments are relatively scarce worldwide and are generally associated with volcanic activity or mining operations. For most acidic environments, low pH facilitates metal solubility, and therefore acidic waters tend to have high concentrations of heavy metals. However, highly acidic environments are usually inhabited by acidophilic and acidotolerant eukaryotic microorganisms such as algae, amoebas, ciliates, heliozoan and rotifers, not to mention filamentous fungi and yeasts. Here, we review the general trends concerning the diversity and ecophysiology of eukaryotic acidophilic microorganims, as well as summarize our latest results on this topic in one of the largest extreme acidic rivers, Río Tinto (SW, Spain).

  15. Eukaryotic Organisms in Extreme Acidic Environments, the Río Tinto Case

    Directory of Open Access Journals (Sweden)

    Angeles Aguilera

    2013-07-01

    Full Text Available A major issue in microbial ecology is to identify the limits of life for growth and survival, and to understand the molecular mechanisms that define these limits. Thus, interest in the biodiversity and ecology of extreme environments has grown in recent years for several reasons. Some are basic and revolve around the idea that extreme environments are believed to reflect early Earth conditions. Others are related to the biotechnological potential of extremophiles. In this regard, the study of extremely acidic environments has become increasingly important since environmental acidity is often caused by microbial activity. Highly acidic environments are relatively scarce worldwide and are generally associated with volcanic activity or mining operations. For most acidic environments, low pH facilitates metal solubility, and therefore acidic waters tend to have high concentrations of heavy metals. However, highly acidic environments are usually inhabited by acidophilic and acidotolerant eukaryotic microorganisms such as algae, amoebas, ciliates, heliozoan and rotifers, not to mention filamentous fungi and yeasts. Here, we review the general trends concerning the diversity and ecophysiology of eukaryotic acidophilic microorganims, as well as summarize our latest results on this topic in one of the largest extreme acidic rivers, Río Tinto (SW, Spain.

  16. Early treatment with Lactobacillus delbrueckii strain induces an increase in intestinal T-cells and granulocytes and modulates immune-related genes of larval Dicentrarchus labrax (L.).

    Science.gov (United States)

    Picchietti, Simona; Fausto, Anna Maria; Randelli, Elisa; Carnevali, Oliana; Taddei, Anna Rita; Buonocore, Francesco; Scapigliati, Giuseppe; Abelli, Luigi

    2009-03-01

    Lactobacillus delbrueckii ssp. delbrueckii (AS13B), isolated from the gut of adult Dicentrarchus labrax, was administered live to developing sea bass using rotifers and Artemia as live carriers. Immune-related gene transcripts were quantified in post-larvae at day 70 post-hatch (ph) and histology, electron microscopy and immunocytochemistry of the intestinal tissue were performed at day 74 ph. Since the probiotic was orally administered the studies were focused on intestinal immunity. In treated fish gut integrity was unaffected, while the density of T-cells and acidophilic granulocytes in the intestinal mucosa was significantly higher than in controls. Probiotic-induced increases in intestinal T-cells and total body TcR-beta transcripts are first reported in fish. Significantly lower IL-1beta transcripts and a trend towards lower IL-10, Cox-2 and TGF-beta transcription were found in the treated group. Evidence is provided that early feeding with probiotic-supplemented diet stimulated the larval gut immune system and lowered transcription of key pro-inflammatory genes.

  17. Fecundity, growth, and survival of the angelfish Pterophyllum scalare (Perciformes: Cichlidae) under laboratory conditions.

    Science.gov (United States)

    Ortega-Salas, Armando A; Cortés G, Isabel; Reyes-Bustamante, Hugo

    2009-09-01

    The freshwater angelfishes (Pterophyllum) are South American cichlids that have become very popular among aquarists, yet scarce information on their culture and aquarium husbandry exists. We studied Pterophyllum scalare to analyze dietary effects on fecundity, growth, and survival of eggs and larvae during 135 days. Three diets were used: A) decapsulated cysts of Artemia, B) commercial dry fish food, and C) a mix diet of the rotifer Brachionus plicatilis and the cladoceran Daphnia magna. The initial larval density was 100 organisms in each 40 L aquarium. With diet A, larvae reached a maximum weight of 3.80 g, a total length of 6.3 cm, and a height of 5.8 cm; with diet B: 2.80 g, 4.81 cm, and 4.79 cm, and with diet C: 3.00 g, 5.15 cm, and 5.10 cm, respectively. Significant differences were observed between diet A, and diet B and C, but no significantly differences were observed between diets B and C. Fecundity varied from 234 to 1,082 eggs in 20 and 50 g females, respectively. Egg survival ranged from 87.4% up to 100%, and larvae survival (80 larvae/40 L aquarium) from 50% to 66.3% using diet B and A, respectively. Live food was better for growing fish than the commercial balanced food diet. Fecundity and survival are important factors in planning a good production of angelfish. PMID:19928467

  18. Cultural characteristics of chromium resistant filamentous cyanobacteria isolated from local environment in Pakistan

    International Nuclear Information System (INIS)

    Many filamentous cyanobacteria were isolated from different places: fields, ponds, polluted water and soils from Muredkey and Kasur tanneries area, near Lahore, Pakistan. Different media like BG 11 medium, Bold Basal medium, Chu's number 10 medium, Gorham's medium and modified SAG medium, in standard forms and with slight variations of ingredients, different pH, temperature and light regimes were checked for the optimum growth of isolates. The isolation procedure was repeated with different concentrations of chromium to select the resistant strains, These selected strains grew on chromium of range 100-200 micro gml/sup -1/ in BG 11 medium. Cyanobacteria were maintained in solid and in liquid media with/without shaking. Cyanobacterial strains were collected from natural habitats that were accompanied by a diversified group of organisms including bacteria, protozoan and rotifers etc. In order to eliminate these agents termed as contaminants, we used several methods including phenol treatment, use of antibiotic and careful manual picking of filamentous cyanobacteria. Resistance of these strains against different heavy metal (ZnSO/sub 4/, MnSO/sub 4/, NiSO/sub 4/, CoCl/sub 2/, Pb (NO/sub 3/)/sub 3/, CuSO/sub 4/, HgCl/sub 2/, AgNO/sub 3/ and CdCl/sub 2/) and antibiotics (erythromycin, streptomycin, kanamycin, chloramphenicol and neomycin) was evolved. Optimum temperature was 35 deg. C with pH 9 for the reduction of Cr (VI) in to Cr (III) in majority. (author)

  19. FLUCTUACIÓN DE LOS ENSAMBLES PLANCTÓNICOS EN LA CIÉNAGA DE AYAPEL (CÓRDOBA-COLOMBIA DURANTE UN CICLO SEMANAL FLUCTUATION OF PLANKTON ASSEMBLAGES AT AYAPEL SWAMP IN CÓRDOBA (COLOMBIA DURING A WEEKLY CYCLE

    Directory of Open Access Journals (Sweden)

    Juan Carlos Jaramillo-Londoño

    2012-12-01

    Full Text Available En esta investigación se evaluó la variación espacial y temporal de los ensamblajes fitoplanctónicos y zooplanctónicos, diariamente y durante un ciclo semanal, en seis estaciones de muestreo en la ciénaga de Ayapel (Córdoba, Colombia, tomando muestras integradas de la columna de agua. Ambos ensamblajes presentaron diferencias espaciales y una alta homogeneidad temporal. El fitoplancton estuvo dominado por cianobacterias principalmente Cylindropermopsis raciborskii y Planktolyngbya limnetica, y el zooplancton por rotíferos del género Brachionus.This research was intended to spatially and temporally evaluate phytoplankton and zooplankton assemblages on a daily basis during a weekly cycle, in six sampling stations at Ayapel swamp in Córdoba (Colombia, taking integrated samples of the water column. Both assemblages showed spatial differences and a high temporal homogeneity. Phytoplankton was dominated by cyanobacteria, specifically Cylindropermopsis raciborskii and Planktolyngbya limnetica; and zooplankton was dominated by Brachionus-genus rotifers..

  20. Biodiversity and community structure of zooplankton in the Sub-basin of Rio Poxim, Sergipe, Brazil

    Directory of Open Access Journals (Sweden)

    Eliane Maria de Souza Nogueira

    2011-08-01

    Full Text Available The zooplankton of aquatic environments is composed mostly of protozoans, rotifers, cladocerans and copepods, which play an important role in the food chain, transferring mass and energy from primary producers to higher trophic levels. This work was prepared with the objective of contributing to the knowledge of zooplankton biodiversity that occurs in the Sub-basin of Rio Poxim. Water samples were taken at monthly intervals at four sampling stations located along the sub-basin in the period August 2009 to July 2010. To obtain the zooplankton community, 100 L of water were filtered on nylon net with an aperture of 50 mm. Were identified 72 taxa distributed in the following taxonomic categories Rotifera, Protozoa, Porifera, Nematoda, Anellida, Cladocera, Copepoda, Ostracoda, Isopoda and Insecta. In terms of species richness, the phylum Rotifera followed by the Protoctista were the most relevant with forty and fifteen taxa, respectively. The most representative taxa in numerical terms were Arcella vulgaris, Notholca sp. Rotary sp. and nematodes. Regarding the community diversity index, the community was characterized as low diversity, but the taxa were distributed evenly in all monitoring points.

  1. A Prehistorical Record of Cultural Eutrophication from Crawford Lake, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, E J; Teranes, J; Guilderson, T; Turton, C L; McAndrews, J H; Wittkop, C A; Stoermer, E F

    2004-08-05

    Cultural eutrophication--the process by which human activities increase nutrient input rates to aquatic ecosystems and thereby cause undesirable changes in surface-water quality--is generally thought to have begun with the start of the industrial era. The prehistoric dimension of human impacts on aquatic ecosystems remains relatively undescribed, particularly in North America. Here we present fossil plankton data (diatoms and rotifers), organic and inorganic carbon accumulations, and carbon isotope ratios from a 1000-yr sediment core record from Crawford Lake, Ontario, Canada. The data documents increased nutrient input to Crawford Lake caused by Iroquoian horticultural activity from A.D. 1268 to 1486 and shows how this increased nutrient input elevated lake productivity, caused bottom-water anoxia, and irreversibly altered diatom community structure within just a few years. Iroquoian settlement in the region declined in the fifteenth century, yet diatom communities and lake circulation never recovered to the predisturbance state. A second phase of cultural eutrophication starting in A.D. 1867, initiated by Canadian agricultural disturbance, increased lake productivity but had comparatively less of an impact on diatom assemblages and carbon-storage pathways than the initial Iroquoian disturbance. This study deepens our understanding of the impact of cultural eutrophication on lake systems, highlights the lasting influence of initial environmental perturbation, and contributes to the debate on the ecological impacts of density and agricultural practices of native North American inhabitants.

  2. Effects of polycyclic aromatic hydrocarbons (PAHs) on an aquatic ecosystem: acute toxicity and community-level toxic impact tests of benzo[a]pyrene using lake zooplankton community.

    Science.gov (United States)

    Ikenaka, Yoshinori; Sakamoto, Masaki; Nagata, Takamaru; Takahashi, Hirokazu; Miyabara, Yuichi; Hanazato, Takayuki; Ishizuka, Mayumi; Isobe, Tomohiko; Kim, Jun-Woo; Chang, Kwang-Hyeon

    2013-02-01

    We estimated acute toxicity of benzo[a]pyrene (B[a]P) using two cladoceran species, Ceriodaphnia reticulata and Daphnia magna, and also analyzed its impact on zooplankton community throughout an exposure experiment using small-scale mesocosms. LC(50) of B[a]P for C. reticulata and D. magna was 4.3 and 4.7 µg/l, respectively. However, individuals fed with Chlorella showed higher LC(50), 6.1 µg/l for C. reticulata and 8.0 µg/l for D. magna. In the exposure experiment, we examined the impact of B[a]P on zooplankton community using conceivable concentrations in the environment (5 and 10 µg/l) using typical zooplankton community in eutrophicated systems. Despite the residence time of B[a]P in the water column was short as impacts, suppressing cladoceran populations and inducing the dominance of rotifers particularly under high concentration (10 µg/l). Results have suggested that, even such short duration of B[a]P in the water body can have impact on zooplankton abundance and community structure. Since B[a]P easily precipitate to the bottom and rapidly disappears from the water body, careful monitoring and further assessment of the potential toxicity of polycyclic aromatic hydrocarbons are necessary.

  3. Genomic diversity amongst Vibrio isolates from different sources determined by fluorescent amplified fragment length polymorphism.

    Science.gov (United States)

    Thompson, F L; Hoste, B; Vandemeulebroecke, K; Swings, J

    2001-12-01

    The genomic diversity among 506 strains of the family Vibrionaceae was analysed using Fluorescent Amplified Fragments Length Polymorphisms (FAFLP). Isolates were from different sources (e.g. fish, mollusc, shrimp, rotifers, artemia, and their culture water) in different countries, mainly from the aquacultural environment. Clustering of the FAFLP band patterns resulted in 69 clusters. A majority of the actually known species of the family Vibrionaceae formed separate clusters. Certain species e.g. V. alginolyticus, V. cholerae, V. cincinnatiensis, V. diabolicus, V. diazotrophicus, V. harveyi, V. logei, V. natriegens, V. nereis, V. splendidus and V. tubiashii were found to be ubiquitous, whereas V. halioticoli, V. ichthyoenteri, V. pectenicida and V. wodanis appear to be exclusively associated with a particular host or geographical region. Three main categories of isolates could be distinguished: (1) isolates with genomes related (i.e. with > or =45% FAFLP pattern similarity) to one of the known type strains; (2) isolates clustering (> or =45% pattern similarity) with more than one type strain; (3) isolates with genomes unrelated (<45% pattern similarity) to any of the type strains. The latter group consisted of 236 isolates distributed in 31 clusters indicating that many culturable taxa of the Vibrionaceae remain as yet to be described.

  4. Evaluation of toxicity and removal of color in textile effluent treated with electron beam; Avaliacao da toxicidade e remocao da cor de um efluente textil tratado com feixe de eletrons

    Energy Technology Data Exchange (ETDEWEB)

    Morais, Aline Viana de

    2015-07-01

    The textile industry is among the main activities Brazil, being relevant in number of jobs, quantity and diversity of products and mainly by the volume of water used in industrial processes and effluent generation. These effluents are complex mixtures which are characterized by the presence of dyes, surfactants, metal sequestering agents, salts and other potentially toxic chemicals for the aquatic biota. Considering the lack of adequate waste management to these treatments, new technologies are essential in highlighting the advanced oxidation processes such as ionizing radiation electron beam. This study includes the preparation of a standard textile effluent chemical laboratory and its treatment by electron beam from electron accelerator in order to reduce the toxicity and intense staining resulting from Cl. Blue 222 dye. The treatment caused a reduction in toxicity to exposed organisms with 34.55% efficiency for the Daphnia similis micro crustacean and 47.83% for Brachionus plicatilis rotifer at a dose of 2.5 kGy. The Vibrio fischeri bacteria obtained better results after treatment with a dose of 5 kGy showing 57.29% efficiency. Color reduction was greater than 90% at a dose of 2.5 kGy. This experiment has also carried out some preliminary tests on the sensitivity of the D. similis and V. fischeri organisms to exposure of some of the products used in this bleaching and dyeing and two water reuse simulations in new textile processing after the treating the effluent with electron beam. (author)

  5. Day-Night Vertical Distribution and Feeding Patterns of Fourth Instar ofChaoborus Larvae in a Neotropical Reservoir (Socuy Reservoir, Venezuela)

    Science.gov (United States)

    López, Carlos; Zoppi de Roa, Evelyn

    2005-05-01

    The day-night vertical distribution, diel feeding activity and diet of fourth instar of Chaoborus larvae were analyzed in lacustrine zone of a neotropical reservoir which shows seasonally contrasting hypolimnetic oxygen conditions. Larvae stayed in sediment and water bottom during day and ascended to surface during night. Results indicate that feeding activity is limited mainly to the plankton population. Phytoplankton, rotifers or remains of Chaoborus larvae were not found in crops. With the exception of ostracods, all crustacean prey available in the zooplankton occurred in the guts. Ceriodaphnia cornuta and Moina micrura were the most frequent food items (about 75% of occurrence frequency) and were positively selected. The remainder crustacean zooplankton taxa were negatively selected by larvae. The most intense feeding activity in larvae occurred near midnight and sunrise, in dates when the hypolimnion was anoxic. When oxygen was available on the bottom, a higher and not changing diel feeding activity was detected. Our results indicate that vertical migration may promote a spatial separation between larvae and zooplankton, and feeding activity of larvae occurred only when both overlapped.

  6. Experimental Study on the Diet of Mosquitofish (Gambusia holbrooki) under Different Ecological Conditions in a Shallow Lake

    Science.gov (United States)

    Blanco, Saúl; Romo, Susana; Villena, María-José

    2004-07-01

    We studied the diet of the eastern mosquitofish Gambusia holbrooki with in situ experimental mesocosms located in a shallow lake. Different nutrient concentrations (phosphorus and nitrogen) and fish population densities were tested. Our results confirm that it is a planktivorous species, with also a great ingestion of algae and detritus. Nutrient fertilization caused almost no changes in this species feeding behavior, but larger mosquitofish stocks induced a shift to zooplanktivory and a decline in detritivory. When macrophytes were present, the predation effect focused on zooplankton and plant-associated animals, otherwise predation on bottom macroinvertebrates increased. Females preyed upon almost all groups more intensely, including detritus. Males and juveniles did not overlap diet, the former being more selective on ostracods, while juveniles consumed detritus, rotifers and cladoceran. Our data support the idea that mosquitofish can cause important top-down effects in shallow lakes under a wide variety of ecological conditions, being an important zooplanktivore in both turbid and plant-dominated shallow lakes especially in the Mediterranean zone, where high temperatures and absence of piscivores promote maintenance of its populations during the whole year. (

  7. Suitability of monotypic and mixed diets for Anopheles hermsi larval development.

    Science.gov (United States)

    Beasley, Donald A; Walton, William E

    2016-06-01

    The developmental time and survival to eclosion of Anopheles hermsi Barr & Guptavanij fed monotypic and mixed diets of ten food types were examined in laboratory studies. Larvae fed monotypic diets containing animal detritus (freeze-dried rotifers, freeze-dried Daphnia pulicaria, and TetraMin® fish food flakes) and the mixotrophic protistan Cryptomonas ovata developed faster and survived better than larvae that were fed other monotypic diets. Survival to adulthood of larvae fed several concentrations of the diatom Planothidium (=Achnanthes) lanceolatum was poor (diet. Larvae fed monotypic diets containing prokaryotes (bacteria [Bacillus cereus] and cyanobacteria [Oscillatoria prolifera]) and brewer's yeast (Saccharomyces cerevisiae) failed to survive beyond the 1(st) and 2(nd) instar, respectively. Larvae fed only chlorophytes, single-celled Chlamydomonas reinhardtii and filamentous Spirogyra communis, failed to complete larval development, regardless of the concentration tested. Cohorts fed a combination of food types (mixed diets) usually developed better than cohorts fed monotypic diets. Food types that failed to support complete development when fed alone often facilitated development to adulthood when fed in combination with food types containing >1% C20 polyunsaturated fatty acids as total fat, but regardless of essential fatty acid content, algae that produced mucilage and filaments that sank out of the feeding zone were poor quality diets.

  8. Loss of sexual reproduction and dwarfing in a small metazoan.

    Directory of Open Access Journals (Sweden)

    Claus-Peter Stelzer

    Full Text Available Asexuality has major theoretical advantages over sexual reproduction, yet newly formed asexual lineages rarely endure. The success, or failure, of such lineages is affected by their mechanism of origin, because it determines their initial genetic makeup and variability. Most previously described mechanisms imply that asexual lineages are randomly frozen subsamples of a sexual population.We found that transitions to obligate parthenogenesis (OP in the rotifer Brachionus calyciflorus, a small freshwater invertebrate which normally reproduces by cyclical parthenogenesis, were controlled by a simple Mendelian inheritance. Pedigree analysis suggested that obligate parthenogens were homozygous for a recessive allele, which caused inability to respond to the chemical signals that normally induce sexual reproduction in this species. Alternative mechanisms, such as ploidy changes, could be ruled out on the basis of flow cytometric measurements and genetic marker analysis. Interestingly, obligate parthenogens were also dwarfs (approximately 50% smaller than cyclical parthenogens, indicating pleiotropy or linkage with genes that strongly affect body size. We found no adverse effects of OP on survival or fecundity.This mechanism of inheritance implies that genes causing OP may evolve within sexual populations and remain undetected in the heterozygous state long before they get frequent enough to actually cause a transition to asexual reproduction. In this process, genetic variation at other loci might become linked to OP genes, leading to non-random associations between asexuality and other phenotypic traits.

  9. FORMATION OF BACTERIAL AND ZOOPLANKTON COMPONENT OF NATURAL FOOD BASE UNDER EFFECT OF TRADITIONAL ORGANIC FERTILIZERS

    Directory of Open Access Journals (Sweden)

    S. Krazhan

    2013-12-01

    Full Text Available Purpose. Characterization of bacteria and zooplankton in rearing ponds using traditional fertilizers: cattle manure and bird droppings in modern conditions for fish farming. Methodology. Material collection and processing were carried out according to conventional hydrochemical and hydrobiological methods. Findings. We consider forming of bacteria and zooplankton component of natural food base of Irkliiv herbivorous fish nursery rearing ponds under the influenced of traditional organic fertilizers such as bird droppings (0,12 t/ha and cattle manure (2,0 t/ha. Each pond was planted by ongrowing Nyvka carp larvae (40,0 thousand ind./ha with silver carp (1,0 thousand ind./ha and grass carp larvae (1,0 thousand ind./ha. Qualitative and quantitative development of bacteria and zooplankton in fish-breeding ponds was investigated. The results show that in the development of the studied invertebrate groups of zooplankton in production ponds had no significant differences, except for rotifers, which group prevailed by the biomass to 3,6 times in the pond with the introduction of humus. Originality. The parameters of bacteria and zooplankton by the application of traditional organic fertilizers at present fish farming are studied. Practical value. These quantitative indicators of bacteria and zooplankton of fish-rearing ponds with water supply from Kremenchug reservoir, the application of cattle manure and bird droppings could be offered as an optimum data at present fish production stage.

  10. Cultural characteristics of chromium resistant unicellular cyanobacteria isolated from local environment in Pakistan

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Many unicellular cyanobacteria were isolated from different places: fields, ponds, polluted water, and soils from Muredkey and Kasur tannery areas, near Lahore, Pakistan. Different media like BG 11 medium, Bold Basal medium, Chu's # 10 medium and Gorham's medium, in standard forms and with slight variations of ingredients, and different pH, temperature and light regimes were checked for the optimum growth of the isolates. The isolation procedure was repeated with different concentrations of chromium to select the resistant strains. These selected strains grew on chromium of the range 100-200 μg/ml in BG 11 medium. Cyanobacteria were maintained in solid and liquid media with/without shaking. Cyanobacterial strains were collected from natural habitats that were accompanied by a diversified group of organisms including bacteria, protozoan, and rotifers etc. In order to eliminate these agents termed as contaminants, we used several methods including phenol treatment, use of antibiotic and careful manual picking of unicellular cyanobacteria. Resistance of these strains against different heavy metals (ZnSO4, MnSO4,NiSO4, CoCl2, Pb(NO3)3, CuSO4, HgCl2, AgNO3 and CdCl2) and antibiotics (erythromycin, streptomycin, kanamycin,chloramphenicol, neomycin) was evaluated. Optimum temperature was 30℃ with variable pH for the reduction of Cr6+ in to Cr3+ in majority of strains.

  11. Zooplankton structure in two interconnected ponds: similarities and differences

    Directory of Open Access Journals (Sweden)

    Špoljar Maria

    2016-03-01

    Full Text Available The research of zooplankton diversity, abundance and trophic structure was conducted during the summer period in pelagial zone on the longitudinal profile of the Sutla River Backwater. Investigated site consists of two interconnected basins: transparent Upper Basin with submerged macrophytes and turbid Lower Basin without macrophytes in the littoral zone. In the Upper Basin, abundance and diversity of zooplankton in the pelagial was higher in comparison to the Lower Basin, with prevailing species of genus Keratella as microfilter-feeder, and genera of Polyartha and Trihocerca as macrofilter-feeder rotifers. On the contrary, in the Lower Basin, crustaceans dominated in abundance. Microfilter-feeder cladoceran (Bosmina longirostris and larval and adult stages of macrofilter-feeder copepod (Macrocyclops albidus prevailed in the Lower Basin. Fish predation pressure was more pronounced in the pelagial of the Upper Basin, indicated by low cladoceran abundance in the surface layer. Although the studied basins were interconnected, results indicate significant (Mann-Whitney U test, p < 0.05 differences in the zooplankton structure as a potential result of the macrophyte impact on environmental conditions and fish predation pressure.

  12. Use of carbon and nitrogen stable isotope ratios to assess the effects of environmental contaminants on aquatic food webs

    International Nuclear Information System (INIS)

    In this study, the value of carbon (δ 13C) and nitrogen (δ 15N) stable isotope ratios were determined in nymphs of a top-predator, the common backswimmer (Notonecta glauca L.), collected in 18 m3 outdoor freshwater mesocosms used to assess the fate and ecotoxicological effects of a diphenyl ether herbicide, fomesafen, applied alone or in combination with Agral 90[reg] (mixture of polyethoxylated derivatives of nonylphenol). Both treatments had a negative effect on δ 13C values which may reflect changes in carbon fluxes across food webs in the treated ponds associated with a shift in phytoplankton structure. A decrease in δ 15N values was observed in the nymphs collected in mixture-treated ponds, which was presumably due to an increase in the abundance of rotifers and Chironominae larvae in these ponds. These preliminary results indicate that stable isotope ratios may be used as shortcuts to detect qualitative or quantitative shifts in the structure of aquatic food webs caused by pollutants. - Carbon and nitrogen stable isotope ratios may be used to detect the impact of pollutants on aquatic food webs

  13. Effects of Climate Warming, North Atlantic Oscillation, and El Niño-Southern Oscillation on Thermal Conditions and Plankton Dynamics in Northern Hemispheric Lakes

    Directory of Open Access Journals (Sweden)

    Dieter Gerten

    2002-01-01

    Full Text Available Impacts of climate warming on freshwater ecosystems have been documented recently for a variety of sites around the globe. Here we provide a review of studies that report long-term (multidecadal effects of warming trends on thermal properties and plankton dynamics in northern hemispheric lakes. We show that higher lake temperatures, shorter periods with ice cover, and shorter stagnation periods were common trends for lakes across the hemisphere in response to the warmer conditions. Only for shallow dimictic lakes was it observed that deep-water temperatures decreased. Moreover, it became evident that phytoplankton dynamics and primary productivity altered in conjunction with changes in lake physics. Algal spring blooms developed early and were more pronounced in several European lakes after mild winters with short ice cover periods, and primary productivity increased in North American lakes. Effects of elevated temperatures on zooplankton communities were seen in an early development of various species and groups, as is documented for cladocerans, copepods, and rotifers in European lakes. Furthermore, thermophile species reached higher abundance in warmer years.

  14. Study on Algae Removal by Immobilized Biosystem on Sponge

    Institute of Scientific and Technical Information of China (English)

    PEI Haiyan; HU Wenrong

    2006-01-01

    In this study, sponges were used to immobilize domesticated sludge microbes in a limited space, forming an immobilized biosystem capable of algae and microcystins removal. The removal effects on algae, microcystins and UV260 of this biosystem and the mechanism of algae removal were studied. The results showed that active sludge from sewage treatment plants was able to remove algae from a eutrophic lake's water after 7 d of domestication. The removal efficiency for algae,organic matter and microcystins increased when the domesticated sludge was immobilized on sponges. When the hydraulic retention time (HRT) was 5h, the removal rates of algae, microcystins and UV260 were 90%, 94.17% and 84%, respectively.The immobilized biosystem consisted mostly of bacteria, the Ciliata and Sarcodina protozoans and the Rotifer metazoans.Algal decomposition by zoogloea bacteria and preying by microcreatures were the two main modes of algal removal, which occurred in two steps: first, absorption by the zoogloea; second, decomposition by the zoogloea bacteria and the predacity of the microcreatures.

  15. Feeding ecology of the freshwater crab Trichodactylus borellianus (Decapoda: Trichodactylidae in the floodplain of the Paraná River, southern South America

    Directory of Open Access Journals (Sweden)

    Verónica Williner

    2013-09-01

    Full Text Available Freshwater crabs are not commonly considered to be an important group in trophic webs, and this might be due to a lack of knowledge about their trophic roles in aquatic ecosystems. Trichodactylus borellianus is one of the most common and widely distributed freshwater crabs in the floodplains of the southern South American rivers. The main objective of the present study was to examine the trophic role of T. borellianus, in the floodplain of the Paraná River, and its relationships with the freshwater littoral community. The trophic spectrum of this species was characterized for both sexes and individuals of different sizes (adults and juveniles, throughout daily and seasonal cycles. Samples were collected from the aquatic vegetation of three shallow lakes. The diet composition and the feeding activity of T. borellianus were evaluated through the examination of the stomach contents and their degree of emptiness. This crab species consumed several plant and animal items, including amoebas, rotifers, oligochaetes, copepods, cladocerans, and insect larvae. Moreover, this species consumes filamentous and unicellular algae, diatoms, fungi, and macrophytic remains. The predatory habits varied with the season and time of day, and variations in the feeding activity of the juveniles and adults were detected and documented. The diversity of food items eaten by this crab suggests that its trophic role in the community as an omnivore and opportunistic predator provides a connection among several trophic levels from both aquatic and terrestrial communities.

  16. Suitability of monotypic and mixed diets for Anopheles hermsi larval development.

    Science.gov (United States)

    Beasley, Donald A; Walton, William E

    2016-06-01

    The developmental time and survival to eclosion of Anopheles hermsi Barr & Guptavanij fed monotypic and mixed diets of ten food types were examined in laboratory studies. Larvae fed monotypic diets containing animal detritus (freeze-dried rotifers, freeze-dried Daphnia pulicaria, and TetraMin® fish food flakes) and the mixotrophic protistan Cryptomonas ovata developed faster and survived better than larvae that were fed other monotypic diets. Survival to adulthood of larvae fed several concentrations of the diatom Planothidium (=Achnanthes) lanceolatum was poor (Chlamydomonas reinhardtii and filamentous Spirogyra communis, failed to complete larval development, regardless of the concentration tested. Cohorts fed a combination of food types (mixed diets) usually developed better than cohorts fed monotypic diets. Food types that failed to support complete development when fed alone often facilitated development to adulthood when fed in combination with food types containing >1% C20 polyunsaturated fatty acids as total fat, but regardless of essential fatty acid content, algae that produced mucilage and filaments that sank out of the feeding zone were poor quality diets. PMID:27232128

  17. Physicochemistry and zooplankton of two karstic sinkholes in the Yucatan Peninsula, Mexico

    Directory of Open Access Journals (Sweden)

    Adrian Cervantes-Martinez

    2014-12-01

    Full Text Available The planktonic communities composed of rotifers and crustaceans of two tropical karstic lakes in the Yucatan Peninsula, Mexico, with similar origin but different trophic state were analyzed. Both systems, the meso-eutrophic (El Padre and oligotrophic (Minicenote were considered as monomictic lakes. The abundance, temporal distribution of species, richness and diversity were measured and discussed in relation to the influence of abiotic factors and the presence of a natural predator. These analyses indicated that these tropical systems were not homogenous for several of these measures at both spatial scales and during the annual cycle analyzed, despite their reduced temperature variation compared to temperate lakes. The results indicated that the dynamics in the zooplankton community were related to the environmental factors, the opportunistic species (with maximum densities related to resource maxima, and the exploitative competition between the dominant herbivorous species. Independently of the trophic condition, the abundance, richness, and diversity were lower during the mixing period. During the annual cycle studied in the meso-eutrophic system, the key environmental parameters related to plankton abundance were pH and temperature whereas in the oligotrophic system, oxygen concentration was important. In both lakes, richness and diversity were related to conductivity, although in the oligotrophic lake the relation was negative whereas in the meso-eutrophic lake it was positive. No relationship was found between the abundance of the studied predator (Chaoborus sp. and the changes in the abundance, diversity and richness of zooplankton in the systems.

  18. The Anhydrobiotic Potential of the Terrestrial Nematodes Plectus parietinus and Plectus velox.

    Science.gov (United States)

    Sandhove, Julian; Spann, Nicole; Ristau, Kai

    2016-08-01

    Within the taxon Nematoda, many species possess an anhydrobiotic potential similar to other microscopic animals, such as tardigrades and rotifers. This interesting capability enables them to survive conditions even of extreme dehydration. We examined the anhydrobiotic abilities of the two widespread terrestrial nematode species, Plectus parietinus and P. velox, by subjecting adult and juvenile life stages of both species to two different desiccation regimes, one with a short time of adaption (2 hr) and the other with a long time of adaption (48 hr) prior to complete desiccation and recorded the nematodes' recovery after 24 hr of rehydration. We found adults of P. parietinus to be the superior anhydrobiotes compared to adults of P. velox at short times of adaption, whereas at a long time of adaption this pattern was reversed. Moreover, our results showed that a long time of adaption significantly increased the recovery rate, independent of species or life stage. Additionally, we found adults to have a remarkable higher anhydrobiotic potential than juveniles, presumably due to a larger amount of resources in adult nematodes or due to a different morphology (cuticle, surface area to volume ratio). Plectus parietinus as well as P. velox showed a distinct anhydrobiotic potential although there were obvious differences between those two species, probably ascribable to different species-specific anhydrobiotic mechanisms and rates of water loss. PMID:27453563

  19. Evaluation of toxicity and removal of color in textile effluent treated with electron beam

    International Nuclear Information System (INIS)

    The textile industry is among the main activities Brazil, being relevant in number of jobs, quantity and diversity of products and mainly by the volume of water used in industrial processes and effluent generation. These effluents are complex mixtures which are characterized by the presence of dyes, surfactants, metal sequestering agents, salts and other potentially toxic chemicals for the aquatic biota. Considering the lack of adequate waste management to these treatments, new technologies are essential in highlighting the advanced oxidation processes such as ionizing radiation electron beam. This study includes the preparation of a standard textile effluent chemical laboratory and its treatment by electron beam from electron accelerator in order to reduce the toxicity and intense staining resulting from Cl. Blue 222 dye. The treatment caused a reduction in toxicity to exposed organisms with 34.55% efficiency for the Daphnia similis micro crustacean and 47.83% for Brachionus plicatilis rotifer at a dose of 2.5 kGy. The Vibrio fischeri bacteria obtained better results after treatment with a dose of 5 kGy showing 57.29% efficiency. Color reduction was greater than 90% at a dose of 2.5 kGy. This experiment has also carried out some preliminary tests on the sensitivity of the D. similis and V. fischeri organisms to exposure of some of the products used in this bleaching and dyeing and two water reuse simulations in new textile processing after the treating the effluent with electron beam. (author)

  20. Effects of acute gamma-irradiation on the aquatic microbial microcosm in comparison with chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Fuma, Shoichi, E-mail: fuma@nirs.go.j [Environmental Radiation Effects Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Ishii, Nobuyoshi; Takeda, Hiroshi; Miyamoto, Kiriko; Yanagisawa, Kei [Environmental Radiation Effects Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Doi, Kazutaka; Kawaguchi, Isao [Regulatory Sciences Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Tanaka, Nobuyuki [Environmental Chemistry Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan); Inamori, Yuhei [Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanayagawa, Fukushima 960-1296 (Japan); Polikarpov, Gennady G. [The A.O. Kovalevsky Institute of Biology of Southern Seas, Sevastopol 99011 (Ukraine)

    2009-12-15

    Effects of acute gamma-irradiation were investigated in the aquatic microcosm consisting of green algae (Chlorella sp. and Scenedesmus sp.) and a blue-green alga (Tolypothrix sp.) as producers; an oligochaete (Aeolosoma hemprichi), rotifers (Lecane sp. and Philodina sp.) and a ciliate protozoan (Cyclidium glaucoma) as consumers; and more than four species of bacteria as decomposers. At 100 Gy, populations were not affected in any taxa. At 500-5000 Gy, one or three taxa died out and populations of two or three taxa decreased over time, while that of Tolypothrix sp. increased. This Tolypothrix sp. increase was likely an indirect effect due to interspecies interactions. The principal response curve analysis revealed that the main trend of the effects was a dose-dependent population decrease. For a better understanding of radiation risks in aquatic microbial communities, effect doses of gamma-rays compared with copper, herbicides and detergents were evaluated using the radiochemoecological conceptual model and the effect index for microcosm.

  1. Effects of acute {gamma}-irradiation on community structure of the aquatic microbial microcosm

    Energy Technology Data Exchange (ETDEWEB)

    Fuma, Shoichi, E-mail: fuma@nirs.go.j [Environmental Radiation Effects Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Ishii, Nobuyoshi; Takeda, Hiroshi [Environmental Radiation Effects Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Doi, Kazutaka; Kawaguchi, Isao [Regulatory Sciences Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Shikano, Shuichi [Center for Northeast Asian Studies, Tohoku University, 41 Kawauchi, Aoba-ku, Sendai, Miyagi 980-8576 (Japan); Tanaka, Nobuyuki [Marine Environment Section, Water and Soil Environment Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan); Inamori, Yuhei [Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanayagawa, Fukushima 960-1296 (Japan)

    2010-11-15

    To characterise indirect effects of ionising radiation on aquatic microbial communities, effects of acute {gamma}-irradiation were investigated in a microcosm consisting of populations of green algae (Chlorella sp. and Scenedesmus sp.) and a blue-green alga (Tolypothrix sp.) as producer; a ciliate protozoan (Cyclidium glaucoma), rotifers (Lecane sp. and Philodina sp.) and an oligochaete (Aeolosoma hemprichi) as consumer; and more than four species of bacteria as decomposers. Population changes in the constituent organisms were observed over 160 days after irradiation. Prokaryotic community structure was also examined by denaturing gradient gel electrophoresis (DGGE) of 16S rDNA. Principle response curve analysis revealed that the populations of the microcosm as a whole were not significantly affected at 100 Gy while they were adversely affected at 500-5000 Gy in a dose-dependent manner. However, some effects on each population, including each bacterial population detected by DGGE, did not depend on radiation doses, and some populations in the irradiated microcosm were larger than those of the control. These unexpected results are regarded as indirect effects through interspecies interactions, and possible mechanisms are proposed originating from population changes in other organisms co-existing in the microcosm. For example, some indirect effects on consumers and decomposers likely arose from interspecies competition within each trophic level. It is also likely that prey-predator relationships between producers and consumers caused some indirect effects on producers.

  2. Cultural characteristics of chromium resistant unicellular cyanobacteria isolated from local environment in Pakistan

    Science.gov (United States)

    Hameed, Abdul; Hasnain, Shahida

    2005-12-01

    Many unicellular cyanobacteria were isolated from different places: fields, ponds, polluted water, and soils from Muredkey and Kasur tannery areas, near Lahore, Pakistan. Different media like BG 11 medium, Bold Basal medium, Chu's #10 medium and Gorham's medium, in standard forms and with slight variations of ingredients, and different pH, temperature and light regimes were checked for the optimum growth of the isolates. The isolation procedure was repeated with different concentrations of chromium to select the resistant strains. These selected strains grew on chromium of the range 100-200 μg/ml in BG 11 medium. Cyanobacteria were maintained in solid and liquid media with/without shaking. Cyanobacterial strains were collected from natural habitats that were accompanied by a diversified group of organisms including bacteria, protozoan, and rotifers etc. In order to eliminate these agents termed as contaminants, we used several methods including phenol treatment, use of antibiotic and careful manual picking of unicellular cyanobacteria. Resistance of these strains against different heavy metals (ZnSO4, MnSO4, NiSO4, CoCl2, Pb(NO3)3, CuSO4, HgCl2, AgNO3 and CdCl2) and antibiotics (erythromycin, streptomycin, kanamyci chloramphenicol, neomycin) was evaluated. Optimum temperature was 30°C with variable pH for the reduction of Cr6+ in to Cr3+ in majority of strains.

  3. Zooplankton of Lake Orta after liming: an eleven years study

    Directory of Open Access Journals (Sweden)

    Andrea PASTERIS

    2001-02-01

    Full Text Available Lake Orta (N. Italy was severely polluted from 1927 by an effluent from a rayon factory, which discharged great amounts of ammonium nitrogen and copper into the lake. In the mid nineteen fifties, some plating factories also started dumping chromium and aluminum. As a result of ammonium oxidation, the lake became very acid and the concentration of metals in the waters reached very high values. Phytoplankton, zooplankton and fish disappeared suddenly from the lake which was by 1930 classified as “sterile”. Later on, about the fifties, a small population of Cyclops abyssorum re-colonised the lake together with some rotifers, in particular Hexarthra fennica. In mid eighties following the introduction of anti-pollution legislation, ammonium loads were greatly reduced and Daphnia obtusa was recorded. The lake waters however were still very acid, prompting the proposal of the Istituto Italiano di Idrobiologia to lime the lake with calcium carbonate to neutralise the excess acidity and reconstruct the alkaline reserve. This was done successfully from May 1989 to June 1990. pH values began to rise and in the same time the metal concentrations decreased, so that at present the lake waters are almost “normal”. In the meantime, due to the increased pH values, D. obtusa was replaced by D. longispina and, as toxic metal concentrations became lower, Megacyclops viridis, Bosmina longirostris, Diaphanosoma brachyurum, Keratella quadrata, Asplanchna priodonta. and other Brachionidae species appeared. Diaptomidae are still absent, except for some specimens of Arctodiaptomus wierzejskii.

  4. Lake Orta: the undermining of an ecosystem

    Directory of Open Access Journals (Sweden)

    Carla BONACINA

    2001-02-01

    Full Text Available From 1927 to 1986 Lake Orta (North-western Italy received loadings coming from a rayon factory, rich in copper and ammonium sulphate. Immediately after the onset of pollution, the food web was destroyed: first phytoplankton, then zooplankton, and finally fish and ultraplankton disappeared from the lake. Twenty years later a rise in nitrate nitrogen and copper ions was recorded and in the early sixties ammonium nitrogen started to accumulate and pH to fall. In the meanwhile, a poorly structured biological community appeared, mainly composed of Cyclops abyssorum (copepod, Hexarthra fennica (rotifer and Coccomyxa minor (green alga. Fish and benthonic animals were still absent. In 1986 the ammonium loading was substantially reduced (copper had been partially recovered since 1956, so that the in-lake ammonium concentration began to decrease. Some phyto- and zooplankton as well as benthic species were recorded in this period. Nevertheless, as pH was still very acid and alkaline reserve absent: a proposal to lime the lake was accepted and funded by regional authorities. Liming was performed in May 1989-June 1990 and resulted in a real improvement of the environment.

  5. Effects of calanoid copepod Schmackeria poplesia as a live food on the growth, survival and fatty acid composition of larvae and juveniles of Japanese flounder, Paralichthys olivaceus

    Science.gov (United States)

    Liu, Guangxing; Xu, Donghui

    2009-12-01

    Zooplankton constitutes a major part of the diet for fish larvae in the marine food web, and it is generally believed that copepods can meet the nutritional requirements of fish larvae. In this study, calanoid copepod Schmackeria poplesia, rotifer Brachionus plicatilis and anostraca crustacean Artemia sp. were analyzed for fatty acid contents, and were used as live food for culturing larval Japanese flounder, Paralichthys olivaceus. The total content of three types of HUFAs (DHA, EPA and ARA) in S. poplesia was significantly higher than that in the other two live foods ( PDHA, EPA and ARA) and the ratio of DHA/EPA in larval and juvenile flounder P. olivaceus were analyzed. The results showed that the contents of DHA, EPA and ARA in the larvae and juveniles fed with S. poplesia were higher than those fed with a mixed diet or Artemia only, and the ratio of EPA/ARA in larvae and juveniles of P. olivaceus fed with S. poplesia was lower than that in the case of feeding with a mixed diet or Artemia only. The present data showed that copepod is the best choice for feeding the larvae and juveniles of fish considering its effects on the survival, growth and nutrition composition of the fish.

  6. Coexisting cyclic parthenogens comprise a holocene species flock in Eubosmina.

    Directory of Open Access Journals (Sweden)

    Markéta Faustová

    Full Text Available BACKGROUND: Mixed breeding systems with extended clonal phases and weak sexual recruitment are widespread in nature but often thought to impede the formation of discrete evolutionary clusters. Thus, cyclic parthenogens, such as cladocerans and rotifers, could be predisposed to "species problems" and a lack of discrete species. However, species flocks have been proposed for one cladoceran group, Eubosmina, where putative species are sympatric, and there is a detailed paleolimnological record indicating a Holocene age. These factors make the Eubosmina system suitable for testing the hypotheses that extended clonal phases and weak sexual recruitment inhibit speciation. Although common garden experiments have revealed a genetic component to the morphotypic variation, the evolutionary significance of the morphotypes remains controversial. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, we tested the hypothesis of a single polymorphic species (i.e., mixing occurs but selection maintains genes for morphology in four northern European lakes where the morphotypes coexist. Our evidence is based on nuclear DNA sequence, mitochondrial DNA sequence, and morphometric analysis of coexisting morphotypes. We found significant genetic differentiation, genealogical exclusivity, and morphometric differentiation for coexisting morphotypes. CONCLUSIONS: We conclude that the studied morphotypes represent a group of young species undergoing speciation with apparent reproductive barriers despite coexistence in the freshwater pelagic zone.

  7. Structure of microbial communities in Sphagnum peatlands and effect of atmospheric carbon dioxide enrichment.

    Science.gov (United States)

    Mitchell, E A D; Gilbert, D; Buttler, A; Amblard, C; Grosvernier, P; Gobat, J M

    2003-08-01

    Little is known about the structure of microbial communities in Sphagnum peatlands, and the potential effects of the increasing atmospheric CO2 concentration on these communities are not known. We analyzed the structure of microbial communities in five Sphagnum-dominated peatlands across Europe and their response to CO2 enrichment using miniFACE systems. After three growing seasons, Sphagnum samples were analyzed for heterotrophic bacteria, cyanobacteria, microalgae, heterotrophic flagellates, ciliates, testate amoebae, fungi, nematodes, and rotifers. Heterotrophic organisms dominated the microbial communities and together represented 78% to 97% of the total microbial biomass. Testate amoebae dominated the protozoan biomass. A canonical correspondence analysis revealed a significant correlation between the microbial community data and four environmental variables (Na+, DOC, water table depth, and DIN), reflecting continentality, hydrology, and nitrogen deposition gradients. Carbon dioxide enrichment modified the structure of microbial communities, but total microbial biomass was unaffected. The biomass of heterotrophic bacteria increased by 48%, and the biomass of testate amoebae decreased by 13%. These results contrast with the absence of overall effect on methane production or on the vegetation, but are in line with an increased below-ground vascular plant biomass at the same sites. We interpret the increase in bacterial biomass as a response to a CO2-induced enhancement of Sphagnum exudation. The causes for the decrease of testate amoebae are unclear but could indicate a top-down rather than a bottom-up control on their density.

  8. Succession of aquatic microbial communities as a result of the water quality variations in continuous water

    Institute of Scientific and Technical Information of China (English)

    WANG Rong-chang; WEN Xiang-hua; QIAN Yi

    2004-01-01

    The changes of structural and functional parameters of aquatic microbial communities in continuous water on campus of Tsinghua University, China are investigated by polyurethane foam unit(PFU) method. The measured compositions of the communities include alga, protozoa, and some metazoa(such as rotifers). The measured indicators of water quality include water temperature, pH value, dissolved oxygen(DO), potassium permanganate index(CODMn), total nitrogen(TN), total phosphorus(TP) and chlorophyll-a(Chla). The trophic level, expressed by the trophic level indices(TLIc), is assessed with analytic hierarchy process and principal component analysis(AHP-PCA) method. The changing trends of the structural and functional parameters of aquatic microbial communities, such as Margalef index of diversity(D), Shannon-weaver index of diversity (H), Heterotropy index(HI), number of species when the colonization gets equilibrium(Seq), colonizing speed constant(G) and time spent when 90 percent of Seq colonized in PFU(T90%), are also analyzed. The experimental results showed the succession of aquatic microbial communities along the water flow is consistent with the water quality changes, so the parameters of microbial community can reflect the changes of water quality from the ecological view.

  9. Water and Planktonic Quality of a Palm Oil Effluent Impacted River in Ondo State, Nigeria

    Directory of Open Access Journals (Sweden)

    A.A. Adedeji

    2005-01-01

    Full Text Available -1. The dissolved oxygen content of water rarely went below 3.0 mg L-1 and rarely above 7.0 mg L-1 irrespective of sampling location. Quantitatively, the levels of Fe and Cu with a mean concentration ranging between 3.07?1.58 and 10.35?3.33 mg L-1 were the major elements in the water sample while Na, K, Ca, Mg with mean concentrations between 1.05?0.02 and 4.10?1.65 mg L-1 were the minor elements. Irrespective of the site of sample collection on the river, the concentrations of Cr, Ni, Pb and P (-1 occurred in trace amounts. The phytoplanktonic flora of River Oluwa showed an extensive overlap between the sites due to homogenous climatic and environmental conditions. The recorded taxa consists of ten chlorophytes, five species of diatoms, three cyanophycean species and one euglenophyte. The zooplanktonic fauna consists of six species of rotifers. Spirogyra fluviatilis and Ulothrix zonata were the dominant green algae (Chlorophyta irrespective of the location while Synedra sp. and Fragillaria crotonensis were the dominant diatoms (Bacillariophyta. Quantitatively, samples collected from the Oluagbo and Ebute-Ire locations had significantly higher (p

  10. A preliminary study of freshwater meiofaunal communities at Greenwich Island, South Shetland Islands, Antarctica

    Institute of Scientific and Technical Information of China (English)

    Soraya J. Silva; Minerva Cordovés; Nory González; Leinny González

    2015-01-01

    Meiofaunal communities of three small, shallow freshwater habitats sampled during the austral summer of 2013 in Greenwich Island, South Shetland Islands, Antarctica, are reported. Communities are dominated by tardigrades (85%), nematodes (11%), and rotifers (3%). Collembola, Oligochaeta, crustacean larvae (nauplii) and unidentified organisms account for 0.3%. Total meiofaunal densities reach 11 770 ind∙cm-2, with mean densities (ind∙cm−2) of 1 365.83 ± 2 716.65 (Zone A), 523.67 ± 1 166.48 (Zone B) and 72.17 ± 110.78 (Zone C). Given the age of freshwater habitats, and the general lack of higher-trophic level predatory taxa, those species we report are likely early stage colonizers, and these communities are at an early stage of ecological succession. Non-parametrical analysis revealed the main variables influencing meiofaunal density and distribution are related to granulometric characteristics of sediments and microphytobenthic biomass. There were close relationships between meiofaunal abundance and microphytobenthic biomass, which indicates that benthic microalgae significantly influence meiofaunal distribution. A strong correlation between nematode abundance and the percentage of silt, clay and carbon in the sediment was also shown by canonical correspondence analysis and Spearman rank correlation.

  11. Analysing a large dataset on long-term monitoring of water quality and plankton with the SOM clustering

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    Voutilainen A.

    2012-11-01

    Full Text Available The Self-Organizing Map (SOM proved to be the method of choice for analysing a large heterogeneous ecological dataset. In addition to distributing the data into clusters, the SOM enabled hunting for correlations between the data components. This revealed logical and plausible relationships between and within the environment and groups of organisms. The main conclusions derived from the results were: (i the structure of early summer plankton community significantly differed from that of late summer community in Lake Pyhäselkä and (ii plankton community in late summer was characterized by two functional groups. The first group was formed mainly by phytoplankton, rotifers, and small cladocerans, such as Bosmina spp., and driven by water temperature. The second group was formed by small copepods and the abundant generalist herbivorous cladocerans Daphnia cristata and Limnosida frontosa, which, in turn, associated with chlorophyll a concentration. Biomasses of Bosmina spp. and D. cristata showed decreasing monotonic trends during a 20-year study period supposedly due to oligotrophication. Versatile possibilities to cluster data and hunt for correlations between data components offered by the SOM decisively helped to reveal associations across the original variables and draw conclusions. The results would have been undetectable solely on the basis of unorganised values.

  12. Development of a Hands-On Survey Course in the Physics of Living Systems

    Science.gov (United States)

    Matthews, Megan; Goldman, Daniel I.

    Due to the widespread availability and technological capabilities of modern smartphones, many biophysical systems can be investigated using easily accessible, low-cost, and/or ``homemade'' equipment. Our survey course is structured to provide students with an overview of research in the physics of living systems, emphasizing the interplay between measurement, mechanism, and modeling required to understand principles at the intersection of physics and biology. The course proceeds through seven modules each consisting of one week of lectures and one week of hands-on experiments, called ``microlabs''. Using smartphones, Arduinos, and 3D printed materials students create their own laboratory equipment, including a 150X van Leeuwenhoek microscope, a shaking incubator, and an oscilloscope, and then use them to study biological systems ranging in length scales from nanometers to meters. These systems include population dynamics of rotifer/algae cultures, experimental evolution of multicellularity in budding yeast, and the bio- & neuromechanics involved in animal locomotion, among others. In each module, students are introduced to fundamental biological and physical concepts as well as theoretical and computational tools (nonlinear dynamics, molecular dynamics simulation, and statistical mechanics). At the end of the course, students apply these concepts and tools to the creation of their own microlab that integrates hands-on experimentation and modeling in the study of their chosen biophysical system.

  13. A preliminary study on the microzooplankton of Chilika Lake, a brackish water lagoon on the east coast of India.

    Science.gov (United States)

    Sahu, Biraja Kumar; Srichandan, Suchismita; Panigrahy, R C

    2016-01-01

    Abundance and composition of microzooplankton in Chilika Lake were studied covering three seasons during 2012-2013. Ciliates (19 species), rotifers (13 species), crustacean larvae (2 taxa) and heterotrophic dinoflagellates (2 species) were the four major groups. Ciliates, however, have emerged as the most dominant group throughout the lake in all the seasons except in the freshwater-influenced areas. The average contribution of ciliates was highest (avg. 55.3 ± 38.7 %) during the premonsoon season followed by post-monsoon (avg. 49.0 ± 32.5 %) and monsoon (avg. 47.8 ± 41.6 %) seasons. Crustacean larvae formed the second dominant group whose percentage contribution was marginally high in the premonsoon (avg. 41.2 ± 38.8 %) followed by monsoon (avg. 29.1 ± 27.0 %) and post-monsoon (avg. 28.7 ± 23.4 %). Results of cluster analysis and multidimensional scaling on abundance of microzooplankton depicted well-defined clusters. The stations with high salinity formed a different group indicating seasonal variation in species composition and abundance of microzooplankton is primarily governed by salinity. PMID:26718950

  14. Effect of the diet traditional and non-traditional on the respiration and excretion in larvae of white shrimp Litopenaeus vannamei

    Directory of Open Access Journals (Sweden)

    María Alejandra Medina-Jasso

    2015-11-01

    Full Text Available Objetive. It was studied the respiration and ammoniacal excretion of zoeas and mysis of Litopenaeus vannamei fed with the diet used traditionally (of microalgae and nauplios of artemia and another alternative (not traditional of microalgae with rotifers. Materials and methods. After four hours the oxygen consumption and ammonia excretion in BOD bottles with 60 larvae (closed respirometers was estimated. The concentrations of O2 and NH4 + were measured with an electrode polarográfico in the first case and with the indophenol blue technique for the second. Results. In zoea, oxygen consumption increased with development and showed statistical differences (p=0.023. In mysis, the oxygen consumption were significance in the traditional diet, whereas no differences were alternative (p=0.003. In both stages for the ammoniacal excretion increased development stage and there were detected statistical difference (p<0.001, although to the diets were not noticed significant differences. Conclusions. A higher energy absorption for zoea (I, II y III what mysis (I, II y III larvae was obtained, this is likely an interaction between rates of respiration and excretion caused by variations in the efficiency of absorption by the larvae. The weights obtained in both larvae were not supplied with differences between diets.

  15. Commentary: selenium study on endangered razorback sucker is flawed.

    Science.gov (United States)

    Hamilton, Steven J

    2005-07-01

    The razorback sucker (Xyrauchen texanus) is listed as federally endangered throughout its range. A massive recovery effort by the Recovery Implementation Program for Endangered Fish Species in the Upper Colorado River Basin has focused its efforts in the upper Colorado River. The upper Colorado River basin also has two locations that have been identified by the National Irrigation Water Quality Program as having substantial selenium contamination. Selenium is toxic to fishes, affecting reproductive success. Thus, there is concern about potential effects of selenium on the endangered razorback sucker. Two sets of studies have investigated the effects of selenium on razorback suckers, but study results are conflicting. This commentary evaluates studies that claim selenium is not a problem for razorback sucker. We find that study bias was so pervasive that purported conclusions were unwarranted. Contaminated control water, older life stages of fish tested, lack of methodology for analysis of selenium in water, diet, or fish, use of rotifer food, low feeding rates, low growth rates of fish, and improper storage of site waters resulted in an apparent erroneous linkage of high selenium in whole-body residues with no adverse effects. PMID:15922797

  16. Assessment of Missouri River floodplain invertebrates during historic inundation: implications for river restoration

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    Gosch N.J.C.

    2014-01-01

    Full Text Available Floodplain connectivity is important to aquatic organisms in large rivers. Anthropogenic alterations regulating the Missouri River have limited connectivity and negatively affected native fauna. Determining the biological response to rare inundation events may be important when considering potential restoration options on a regulated river; thus, we assessed benthic invertebrate and zooplankton communities at three floodplain sites during a historic Missouri River high-water event. Chironomid larvae dominated during most sampling trips and densities were often highest during initial sampling trips with lower densities as high water persisted. Similar trends were evident for rotifer, cladoceran, and copepod densities. Nonmetric multidimensional scaling also showed relatively high dissimilarity of densities between early and late sampling trips for benthic invertebrate and zooplankton communities. As such, short-term inundation may be more beneficial to Missouri River benthic invertebrate (mainly chironomid larvae and zooplankton production than more prolonged inundation lasting a month or more. Furthermore, restoration projects may be designed at elevations allowing more short-term inundation, which would likely benefit native fishes with additional spawning, nursery, and foraging habitat. Levee setbacks may be an effective restoration option for increasing the amount of habitat available for short-term inundation while potentially providing socioeconomic, flood-risk reduction benefits by enhancing flow conveyance.

  17. Impacts of algal blooms removal by chitosan-modified soils on zooplankton community in Taihu Lake,China

    Institute of Scientific and Technical Information of China (English)

    Jiajia Ni; Yuhe Yu; Weisong Feng; Qingyun Yan; Gang pan; Bo Yang; Xiang Zhang; Xuemei Li

    2010-01-01

    It is important to assess the effect on zooplankton when perform the environmental protection or restoration technology,especially removing algal blooms,because algae were the major primary producer in algal lakes.The influence on zooplankton community after half a year of algal blooms removed by chitosan-modified soils in Taihu Lake was assessed and the rationality of carrying out the process semiannually was evaluated in the present study.Morphological composition and genetic diversity of zooplankton community were investigated by microscope checkup and polymerase chain reaction-denatured gradient gel electrophoresis (PCR-DGGE).A total of 44 zooplankton taxa (23 protozoa,17 rotifers,3 copepoda and 1 cladocera) were detected by microscope checkup,and a total of 91 bands (28 bands amplified by primers F1427-GC and R1616,63 bands amplified by primers Fung-G-C and NS1) were detected by PCR-DGGE.The results of cluster analysis or detrended correspondence analysis indicated that there was no considerable difference in morphological composition of zooplankton and DGGE profiles between experimental and control sites,and DGGE profiles could represent the biologic diversity.The study showed that zooplankton community could recover original condition after half year of algal blooms removed by chitosan-modified soils and it was acceptable to apply this process semiannually.In addition,the results revealed that PCR-DGGE could be applied to investigate the impacts of the environmental protection or restoration engineering on zooplankton community diversity.

  18. Diet of Mysis diluviana reveals seasonal patterns of omnivory and consumption of invasive species in offshore Lake Michigan

    Science.gov (United States)

    O'Malley, Brian P.; Bunnell, David B.

    2014-01-01

    Recent changes in Lake Michigan’s lower trophic levels were hypothesized to have influenced the diet of omnivorous Mysis diluviana. In this study, the stomach contents of Mysis were examined from juvenile and adults collected monthly (April–October) from a 110-m bottom depth site to describe their seasonal diet in LakeMichigan during 2010. Diatoms were the most common prey item ingested, followed by calanoid copepods, and chrysophytes. Dreissenid veligers were documented in mysid diets for the first time in the Great Lakes, and Cercopagis pengoi were not only consumed but even preferred by adults in summer. Diet proportions by weight were dominated by calanoids, although diets showed a marked shift toward cladocerans in autumn. Juvenile and adult Mysis selected primarily for cladoceran prey but also selected for some calanoid copepod taxa. Comparing available Mysis diet data from 1985 to 2010 indicated generally fewer cladocerans and rotifers per gut and less consistent differences in copepods and Peridinium consumed. The seasonal composition of phyto- and zooplankton prey documented herein should be useful to those seeking to understand the trophic role of Mysis in offshore food webs, but caution should be expressed when generalizing similarities in Mysis diets across other lakes because Lake Michigan’s population seems relatively more herbivorous.

  19. Benthic meiofaunal composition and community structure in the Sethukuda mangrove area and adjacent open sea, East coast of India

    Science.gov (United States)

    Thilagavathi, Balasubramanaian; Das, Bandana; Saravanakumar, Ayyappan; Raja, Kuzhanthaivel

    2011-06-01

    The ecological aspects of meiofaunal communities in the Muthupettai mangrove forest, East coast of India, has not been investigated in the last two decades. Surface water temperature ranged from 23.5 °C to 31.8 °C. Salinity varied from 24 to 34 ppt, while water pH fluctuated from 7.4 to 8.3. Dissolved oxygen concentration ranged from 3.86 to 5.33 mg/l. Meiofauna analysis in this study identified a total of 106 species from the mangrove and adjacent open sea area of Sethukuda. Among these, 56 species of foraminiferans, 20 species of nematodes, 7 species of harpacticoid copepods, 4 species of ostrocodes, and 2 species of rotifers were identified. Furthermore, a single species was identified from the following groups: ciliophora, cnidaria, gnathostomulida, insecta, propulida, bryozoa and polychaete larvae. Meiofaunal density varied between 12029 to 23493 individuals 10 cm/m2. The diversity index ranged from 3.515 to 3.680, species richness index varied from 6.384 to 8.497, and evenness index varied from 0.839 to 0876 in the mangrove area and adjacent open sea.

  20. What shapes edaphic communities in mineral and ornithogenic soils of Cierva Point, Antarctic Peninsula?

    Science.gov (United States)

    Mataloni, G.; Garraza, G. González; Bölter, M.; Convey, P.; Fermani, P.

    2010-08-01

    Three mineral soil and four ornithogenic soil sites were sampled during summer 2006 at Cierva Point (Antarctic Peninsula) to study their bacterial, microalgal and faunal communities in relation to abiotic and biotic features. Soil moisture, pH, conductivity, organic matter and nutrient contents were consistently lower and more homogeneous in mineral soils. Ornithogenic soils supported larger and more variable bacterial abundances than mineral ones. Algal communities from mineral soils were more diverse than those from ornithogenic soils, although chlorophyll- a concentrations were significantly higher in the latter. This parameter and bacterial abundance were correlated with nutrient and organic matter contents. The meiofauna obtained from mineral soils was homogeneous, with one nematode species dominating all samples. The fauna of ornithogenic soils varied widely in composition and abundance. Tardigrades and rotifers dominated the meiofauna at eutrophic O2, where they supported a large population of the predatory nematode Coomansus gerlachei. At site O3, high bacterial abundance was consistent with high densities of the bacterivorous nematodes Plectus spp. This study provides evidence that Antarctic soils are complex and diverse systems, and suggests that biotic interactions (e.g. competition and predation) may have a stronger and more direct influence on community variability in space and time than previously thought.

  1. The annual fluctuation of zooplankton community and its relation with environmental factors in Lake Xiliang, Hubei Province%湖北省西凉湖浮游动物群落周年动态变化及其与环境因子的关系

    Institute of Scientific and Technical Information of China (English)

    吴利; 冯伟松; 张堂林; 徐昊; 余育和

    2011-01-01

    Four zooplanktonic investigations were carried out from November 2007 to October 2008 in Lake Xiliang. Totally, 224 species of zooplankton including 112 species of protozoa, 90 species of rotifer, 15 species of cladocera, and 7 species of copepoda were found. The zooplankton species ranged from 75 to 111, with the lowest value(75) occurring in winter, and the highest one (111) in autumn. The density of zooplankton was the highest in winter( 126731 ind./L) , and the lowest in spring (71356ind./ L). The densities of zooplankton in summer and autumn were 109743ind. /L and 107650ind. /L, respectively, and the abundance of protozoa and rotifer were on predominance. The structure of zooplankton community was analyzed in relation to water quality parameters by canonical correspondence analysis (CCA). Temperature, pH, water depth, and the concentrations of TP, COD and DO were strongly correlated with the zooplankton community structure. The parameters that demonstrated a strong correlation with the zooplankton community structure differed among seasons, suggesting that the seasonal variations of zooplankton community structure were related closely to both the water temperature and water trophic status in Lake Xiliang.%2007年11月至2008年10月对西凉湖浮游动物进行了4次调查,共检出浮游动物224种,其中原生动物112种,轮虫90种,枝角类15种,桡足类7种.秋季浮游动物物种数最多,为111种,冬季最少,为75种,春季和夏季分别为107种和88种.冬季浮游动物丰度最高,为126731 ind./L,春季最低,为71356ind./L,夏季和秋季分别为109743ind./L和107650ind./L,原生动物和轮虫的丰度是西凉湖浮游动物丰度的主体.浮游动物群落结构和环境因子的典型对应分析表明,水温、pH、水深、总磷、化学需氧量和溶解氧是与西凉湖浮游动物群落结构相关性较强的环境因子.冬季浮游动物群落结构与总磷、化学需氧量和溶解氧呈显著正相关;春季、夏

  2. 元荡湖水域后生浮游动物群落特征与水质评价%Features of Metazoan Zooplankton and Water Quality Assessment in Yuandang Lake Area

    Institute of Scientific and Technical Information of China (English)

    胡景; 钟俊生; 郁蔚文; 王忆; 陈立婧

    2016-01-01

    Objective] The aim was to study community features of metazoan zooplankton in Yuandang Lake area and evaluate its water quality. [Method] The species, existing quantity, biological diversity of metazoan zooplankton in Yuandang Lake area was investigated in 2013. [Result] There were 20 species of metazoan zooplankton in the lake, belonging to 11 genera, including 11 species of rotifer ,6 species of cladocera and 3 species of copepoda. The dominant species were Brachionus calyciflorus, Brachionus diversicornis, Notholon labis , Asplanchna brightwel, Dicran-ophorus caudatas, Moina micrura, Bosmina longirostris, Bosmina coregoni , Calanus sinicus, Paracyclops fimbriatus and Onychocamptus moham-med. The statistics indicated that the highest density of metazoan zooplankton was in autumn (184. 7 ind/L). The highest biomass was in spring (1. 193 mg/L). [Conclusion] Based on the Shannon-Wiener index, the B/T index of rotifer, the E/O index of metazoan zooplankton and the species sensitive to eutrophication, biological assessment of water quality suggested that the Yuandang Lake area is on mid-eutrophication.%[目的]研究元荡湖水域后生浮游动物群落特征,对元荡湖水域水质进行初步评价。[方法]于2013年对元荡湖水域后生浮游动物的种类组成、现存量、生物多样性等进行了调查研究。[结果]后生浮游动物共有11属20种,包括轮虫11种,枝角类6种,桡足类3种。主要优势种为萼花臂尾轮虫(Brachionus calyciflorus)、裂足臂尾轮虫(Brachionus diversicornis)、唇形叶轮虫(Notholon labis)、卜氏晶囊轮虫(Asplanchna brightwel)、尾猪吻轮虫(Dicranophorus caudatas)、微型裸腹溞(Moina micrura)、长额象鼻溞(Bosmina longirostris)、简弧象鼻溞(Bosmina coregoni)、中华哲水蚤(Calanus sinicus)、毛饰拟剑水蚤(Paracyclops fimbriatus)和模式有爪猛水溞(Onychocamptus moham-med)。调查数据显示,元荡湖后生浮游动物生物密度最高峰出现在秋季,达184

  3. Zooplankton community composition and some limnological aspects of an oxbow lake of the Paraopeba River, São Francisco River Basin, Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Edson Vieira Sampaio

    2000-01-01

    Full Text Available Some limnological aspects of Lake Massacará (adjoining the Paraopeba River, São Francisco River Basin were studied during two periods of the hydrological cycle. Water transparency was equally low during both the periods. During high water, thermal stratification was recorded, with a clinograde oxygen profile; pH was slightly acid, and conductivity was higher near the bottom. Concentrations of inorganic carbon and ammonia, and rates of primary production were higher than during the low water period. During the latter period, complete mixing occurred, with a clinograde oxygen profile; pH was slightly acid, and conductivity unvarying with depth. Higher concentrations of nitrate were found than during high water. With regard to the zooplankton communities, higher density and species richness of organisms occurred during high water. Copepods and rotifers were most numerous during both periods. The taxa identified consisted of 17 rotifers, four copepods, six cladocerans, five protozoans, and two macroinvertebrates. The most abundant species were Thermocyclops minutus, Keratella cochlearis, K. lenzi, and Trichocerca capucina during high water, and Thermocyclops minutus and Conochilus unicornis during low water.Lagoa Massacará (marginal ao Rio Paraopeba-MG, Bacia do Rio São Francisco foi estudada do ponto de vista de alguns aspectos limnológicos durante dois períodos do ciclo hidrológico (cheia e seca. A transparência da água foi baixa e semelhante nos dois períodos. No período de cheia ocorreu estratificação, perfil de oxigênio clinógrado com camadas inferiores anóxicas, pH ligeiramente ácido, alta condutividade elétrica no fundo, com maiores concentrações de CO2 inorgânico, de íons amônio e taxa de produção primária que na época seca. No período de seca ocorreu desestratificação, perfil de oxigênio clinógrado com camadas inferiores não anóxicas, pH ligeiramente ácido, condutividade elétrica constantes, com maiores

  4. Community Structure of Zooplankton and Its Relationship to Survivability of Yangtze Dolphin in Zhenjiang Yangtze Dolphin Nature Reserve, Jiangsu Province%江苏镇江长江豚类保护区浮游动物群落结构特征及江豚生存状况评估

    Institute of Scientific and Technical Information of China (English)

    代梨梨; 龚迎春; 冯伟松; 余育和

    2011-01-01

    The Zhenjiang Yangtze Dolphin nature reserve in Jiangsu Province, as the rare excellent habitat for Yangtze Dolphin, is the only nature reserve along Yangtze River which has not been exploited for main channel. In order to understand the community structure of zooplankton in this area, seasonal investigation was performed through 2010 to 2011. The results showed that protozoa and rotifers took the dominant places, while the biomass of zooplankton lied on the cladocerans and the copepods. The species abundance, species diversity and biomass of Conservation Area 2 were much higher than other places. Seasonality of different members varied within zooplankton community. The breeding peaks of protozoa and rotifers appeared mainly in spring, while cladocerans and copepods in autumn. The diversity index of zooplankton peaked in summer and autumn, and bottomed out in winter. Through comparing the seasonal variability of zooplankton in different sampling sites, the Main Channel being more disturbed showed more seasonality. Fish potential production estimation through zooplankton showed that food sources of Yangtze Dolphin were being threatened.%江苏镇江长江豚类保护区是唯一没有被开辟为主航道的长江干流豚类保护区,是长江下游少有的长江江豚的优良栖息地。为了解这一地区的浮游动物群落特征,2010-2011年对镇江保护区进行了4个季度的考察和调研。结果表明,在浮游动物种类数和丰度上,原生动物和轮虫占据主导地位,但浮游动物生物量主要由枝角类和桡足类决定。保护区2(现有保护区)的物种丰度、物种多样性及生物量都要明显高于保护区1(拟扩展保护区)和主航道。浮游动物各类群随季节的变化不尽相同,原生动物和轮虫的密度高峰主要出现在春季,而枝角类和桡足类密度高峰主要出现在秋季。浮游动物多样性指数在夏季和秋季时高,在冬季时最低。对不同采样点浮游动

  5. 东江支流夏季小型浮游动物群落特征研究%Aestival Characteristics of Small Zooplankton Communities in the Main Tributaries of the Dongjiang River

    Institute of Scientific and Technical Information of China (English)

    彭秋志; 廖剑宇; 伍凯; 刘全儒; 周云龙; 江源; 龚玲

    2013-01-01

    Our goal was to describe the aestival features of small zooplankton communities in the main tributaries of the Dongjiang River and test the possibility of using prominent features derived from the zooplankton community as predictive indicators of water quality. By systematically selecting representative tributaries of the Dongjiang River as case study sites, we randomly sampled small zooplankton (Protozoa and Rotifers) communities along the tributaries in My 2010. The species composition of those zooplankton communities was identified to the genus level, and indices including richness, density, relative density, frequency and diversity were counted. Environmental variables including temperature, dissolved oxygen, electrical conductivity, total phosphorus, total nitrogen, ammonia nitrogen, nitrate nitrogen, permanganate index, and chlorophyll a were also measured. We identified 36 genera, of which 23 belonged to Protozoa and 13 to Rotifers. Those taxa in most cases emerged in low density and low richness in samples. Within a sample, however, often one of the genera was found at a relatively high density, while fewer genera dominated the density and frequency. This implied that small river channels are not suitable for zooplankton growth, whereas diversified habitats resulted in a variety of community composition types. An increased trend from up- to down-stream was found in density, richness and diversity, while at the same time a decreased trend in dominance occurred. Many factors, such as zooplankton origins, available nutrients and flow velocity, could all be influencing the small zooplankton community. Significant correlations between the density of certain special genera and most environmental variables were found, indicating that density might be used as the zooplankton indicator in assessing and monitoring river environmental conditions. On the contrary, the diversity of zooplankton should not be used as a competent indicator in assessment, since there was no

  6. Ontogenetic changes in digestive enzyme activities and the amino acid profile of starry flounder Platichthys stellatus

    Science.gov (United States)

    Song, Zhidong; Wang, Jiying; Qiao, Hongjin; Li, Peiyu; Zhang, Limin; Xia, Bin

    2016-01-01

    Ontogenetic changes in digestive enzyme activities and the amino acid (AA) profile of starry flounder, Platichthys stellatus, were investigated and limiting amino acids were estimated compared with the essential AA profile between larvae and live food to clarify starry flounder larval nutritional requirements. Larvae were collected at the egg stage and 0, 2, 4, 7, 12, 17, 24 days after hatching (DAH) for analysis. Larvae grew from 1.91 mm at hatching to 12.13 mm at 24 DAH. Trypsin and chymotrypsin activities changed slightly by 4 DAH and then increased significantly 4 DAH. Pepsin activity increased sharply beginning 17 DAH. Lipase activity increased significantly 4 DAH and increased progressively with larval growth. Amylase activity was also detected in newly hatched larvae and increased 7 DAH followed by a gradual decrease. High free amino acid (FAA) content was detected in starry flounder eggs (110.72 mg/g dry weight). Total FAA content dropped to 43.29 mg/g in 4-DAH larvae and then decreased gradually to 13.74 mg/g in 24-DAH larvae. Most FAAs (except lysine and methionine) decreased >50% in 4-DAH larvae compared with those in eggs and then decreased to the lowest values in 24-DAH larvae. Changes in the protein amino acid (PAA) profile were much milder than those observed for FAAs. Most PAAs increased gradually during larval development, except lysine and phenylalanine. The percentages of free threonine, valine, isoleucine, and leucine decreased until the end of the trial, whereas the protein forms of these four AAs followed the opposite trend. A comparison of the essential AA composition of live food (rotifers, Artemia nauplii, and Artemia metanauplii) and larvae suggested that methionine was potentially the first limiting AA. These results may help develop starry flounder larviculture methods by solving the AA imbalance in live food. Moreover, the increased digestive enzyme activities indicate the possibility of introducing artificial compound feed.

  7. Influence of plankton mercury dynamics and trophic pathways on mercury concentrations of top predator fish of a mining-impacted reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, A.R.; Kuwabara, J.S.; Marvin-DiPasquale, M. [United States Geological Survey, Menlo Park, CA (United States); Saiki, M.K. [United States Geological Survey, Western Fisheries Research Center, Dixon, CA (United States); Alpers, C.N. [United States Geological Survey, California Water Science Center, Sacramento, CA (United States); Krabbenhoft, D.P. [United States Geological Survey, Middleton, WI (United States)

    2008-11-15

    A study was conducted to document the water quality in the Camp Far West Reservoir (CFWR) located at 300 feet above sea level in the foothills of the Sierra Nevada in northern California. The CFWR is characterized by drawdown in the late summer and fall. It receives acidic, metal-rich drainage seasonally from an inactive gold mine. Water-quality constituents vary considerably by season. Water-quality data for CFWR were used together with data from studies of sediment and biota to develop a conceptual model for mercury methylation and bioaccumulation in the reservoir and the lower Bear River watershed. The study examined the physical and biogeochemical characteristics of the aquatic environment that affect growth dynamics of phytoplankton and the zooplankton communities that depend on them. The uptake affect of methylmercury (MeHg) into the pelagic food web was also investigated by assessing the changes in the quality and quantity of suspended particulate material, zooplankton taxonomy, and MeHg concentrations with seasonal changes. MeHg concentrations in bulk zooplankton increased at high water and were positively correlated with cladoceran biomass and negatively correlated with rotifer biomass. According to stable isotope analysis, MeHg concentrations in the pelagic-based food web were generally higher than in the benthic-based food web. The difference in MeHg bioaccumulation among trophic pathways appears to be set at the base of the food webs. It was concluded that plankton dynamics plays a key role in driving the MeHg content of zooplankton and MeHg bioaccumulation in top predators in pelagic-based food webs. 58 refs., 1 tab., 8 figs.

  8. Hydroxide stabilization as a new tool for ballast disinfection: efficacy of treatment on zooplankton

    Science.gov (United States)

    Moffitt, Christine M.; Watten, Barnaby J.; Barenburg, Amber; Henquinet, Jeffrey

    2016-01-01

    Effective and economical tools are needed for treating ship ballast to meet new regulatory requirements designed to reduce the introduction of invasive aquatic species from ship traffic. We tested the efficacy of hydroxide stabilization as a ballast disinfection tool in replicated, sequential field trials on board the M/V Ranger III in waters of Lake Superior. Ballast water was introduced into each of four identical 1,320 L stainless steel tanks during a simulated ballasting operation. Two tanks were treated with NaOH to elevate the pH to 11.7 and the remaining two tanks were held as controls without pH alteration. After retention on board for 14–18 h, CO2-rich gas recovered from one of two diesel propulsion engines was sparged into tanks treated with NaOH for 2 h to force conversion of NaOH ultimately to sodium bicarbonate, thereby lowering pH to about 7.1. Prior to gas sparging, the engine exhaust was treated by a unique catalytic converter/wet scrubber process train to remove unwanted combustion byproducts and to provide cooling. The contents of each tank were then drained and filtered through 35-µm mesh plankton nets to collect all zooplankton. The composition and relative survival of zooplankton in each tank were evaluated by microscopy. Zooplankton populations were dominated by rotifers, but copepods and cladocerans were also observed. Hydroxide stabilization was 100% effective in killing all zooplankton present at the start of the tests. Our results suggest hydroxide stabilization has potential to be an effective and practical tool to disinfect ship ballast. Further, using CO2 released from the ship engine reduces emissions and the neutralized by product, sodium bicarbonate, can have beneficial impacts on the aquatic environment.

  9. Zooplankton variability and larval striped bass foraging: Evaluating potential match/mismatch regulation

    Science.gov (United States)

    Chick, J.H.; Van Den Avyle, M.J.

    1999-01-01

    We quantified temporal and spatial variability of zooplankton in three potential nursery sites (river, transition zone, lake) for larval striped bass (Morone saxatilis) in Lake Marion, South Carolina, during April and May 1993-1995. In two of three years, microzooplankton (rotifers and copepod nauplii) density was significantly greater in the lake site than in the river or transition zone. Macrozooplankton (>200 ??m) composition varied among the three sites in all years with adult copepods and cladocerans dominant at the lake, and juvenile Corbicula fluminea dominant at the river and transition zone. Laboratory feeding experiments, simulating both among-site (site treatments) and within-site (density treatments) variability, were conducted in 1995 to quantify the effects of the observed zooplankton variability on foraging success of larval striped bass. A greater proportion of larvae fed in the lake than in the river or transition-zone treatments across all density treatments: mean (x), 10x and 100x. Larvae also ingested significantly more dry mass of prey in the lake treatment in both the mean and 10x density treatments. Field zooplankton and laboratory feeding data suggest that both spatial and temporal variability of zooplankton influence larval striped bass foraging. Prey density levels that supported successful foraging in our feeding experiments occurred in the lake during late April and May in 1994 and 1995 but were never observed in the river or transition zone. Because the rivers flowing into Lake Marion are regulated, it may be possible to devise flow management schemes that facilitate larval transport to the lake and thereby increase the proportion of larvae matched to suitable prey resources.

  10. Food availability promotes rapid recovery from thermal stress in a scleractinian coral

    Science.gov (United States)

    Connolly, S. R.; Lopez-Yglesias, M. A.; Anthony, K. R. N.

    2012-12-01

    Bleaching in corals due to environmental stress represents a loss of energy intake often leading to an increase in mortality risk. Successful coral recovery from severe bleaching events may depend on the rate of replenishment of algal symbiont populations following the period of thermal stress, the supply of an alternative food source, or both. Here, we explore the role of food availability in promoting the survival and recovery of a common coral ( Acropora intermedia) following acute experimentally induced thermal stress. Fed corals were provided with live rotifers daily, to maintain densities of zooplankton in tanks that are typical of coral reefs. After a 6-week acclimation phase, heated corals were subjected to a +4 °C thermal anomaly for a 7-day period (bleaching phase) then temperatures were returned to normal for a further 2 weeks (recovery phase). Results demonstrated that heated corals had higher survival when they were provided with heterotrophic food. Fed corals experienced reduced loss of chlorophyll a, relative to unfed corals. During the recovery phase, both fed and unfed corals recovered within a few days; however, fed corals recovered to pre-bleaching phase levels of chlorophyll a, whereas unfed corals stabilized approximately one-third below this level. Protein levels of fed corals declined markedly during the bleaching phase, but recovered all of their losses by the end of the recovery phase. In contrast, unfed corals had low protein levels that were maintained throughout the experiment. To the extent that these results are representative of corals' responses to thermal anomalies in nature, the findings imply that availability of particulate food matter has the potential to increase corals' capacity to survive thermally induced bleaching and to ameliorate its sub-lethal effects. They also support the hypothesis that different rates of heterotrophy are an important determinant of variation in resilience to thermal stress among reef environments.

  11. A successful microbound diet for the larval culture of Chinese shrimp Fenneropenaeus chinensis

    Science.gov (United States)

    Wang, Xinxia; Mai, Kangsen

    2005-07-01

    A 13-day feeding trial was carried out to evaluate the effectiveness of a microbound diet for rearing the larvae of Chinese shrimp Fenneropenaeus chinensis in comparison with the live foods that consist of Isochrysis galbana, Chlorella vulgaris, Tetraselmis chuii, rotifer (Brachionus plicatilis) and Artemia sp. Larvae of 0 to 13d post-hatch (dph) were reared in a temperature-controlled semi-open culture system and stocked at a density of 100 larvae L-1 in tanks, each containing 50 L sterilized seawater with salinity 30 32. Larvae were manually fed either the live foods or the microbound diet 6 times per day. At 13dph, the growth of the larvae fed on the microbound diet was approximately 84% of that fed on the live foods. The survival rate of the larvae fed on the microbound diet was 44.29% at 13 dph, which was not significantly different from that of larvae fed on live foods (63.55% ). The body length and development index (DI) of the larvae fed on the microbound diet were always lower than those of larvae fed on live foods. However, the differences reached significant levels only at 11 and 13dph (P<0.05). The mean dry weight loss of the microbound diet was 9.2% after 90min immersion in seawater, indicating that this diet has a good water stability. The microbound diet contains 5223% crude protein and 10.27% lipid and is easy to prepare. These characteristics of the diet suggest good potentials for its successful use in the larviculture of other penaeid and fish species.

  12. A Successful Microbound Diet for the Larval Culture of Chinese Shrimp Fenneropenaeus chinensis

    Institute of Scientific and Technical Information of China (English)

    WANG Xinxia; MAI Kangsen

    2005-01-01

    A 13-day feeding trial was carried out to evaluate the effectiveness of a microbound diet for rearing the larvae of Chinese shrimp Fenneropenaeus chinensis in comparison with the live foods that consist of Isochrysis galbana, Chlorella vulgaris, Tetraselmis chuii, rotifer (Brachionus plicatilis) and Artemia sp. Larvae of 0 to 13d post-hatch (dph) were reared in a temperature-controlled semi-open culture system and stocked at a density of 100 larvae L-1 in tanks, each containing 50 L sterilized seawater with salinity 30-32. Larvae were manually fed either the live foods or the microbound diet 6 times per day. At 13 dph, the growth of the larvae fed on the microbound diet was approximately 84% of that fed on the live foods.The survival rate of the larvae fed on the microbound diet was 44.29% at 13 dph, which was not significantly different from that of larvae fed on live foods (63.55%). The body length and development index (DI) of the larvae fed on the microbound diet were always lower than those of larvae fed on live foods. However, the differences reached significant levels only at 11and 13dph (P<0.05). The mean dry weight loss of the microbound diet was 9.2% after 90min immersion in seawater, indicating that this diet has a good water stability. The microbound diet contains 52.23% crude protein and 10.27% lipid and is easy to prepare. These characteristics of the diet suggest good potentials for its successful use in the larviculture of other penaeid and fish species.

  13. Ontogenetic changes in digestive enzyme activities and the amino acid profile of starry flounder Platichthys stellatus

    Science.gov (United States)

    Song, Zhidong; Wang, Jiying; Qiao, Hongjin; Li, Peiyu; Zhang, Limin; Xia, Bin

    2016-09-01

    Ontogenetic changes in digestive enzyme activities and the amino acid (AA) profile of starry flounder, Platichthys stellatus, were investigated and limiting amino acids were estimated compared with the essential AA profile between larvae and live food to clarify starry flounder larval nutritional requirements. Larvae were collected at the egg stage and 0, 2, 4, 7, 12, 17, 24 days after hatching (DAH) for analysis. Larvae grew from 1.91 mm at hatching to 12.13 mm at 24 DAH. Trypsin and chymotrypsin activities changed slightly by 4 DAH and then increased significantly 4 DAH. Pepsin activity increased sharply beginning 17 DAH. Lipase activity increased significantly 4 DAH and increased progressively with larval growth. Amylase activity was also detected in newly hatched larvae and increased 7 DAH followed by a gradual decrease. High free amino acid (FAA) content was detected in starry flounder eggs (110.72 mg/g dry weight). Total FAA content dropped to 43.29 mg/g in 4-DAH larvae and then decreased gradually to 13.74 mg/g in 24-DAH larvae. Most FAAs (except lysine and methionine) decreased >50% in 4-DAH larvae compared with those in eggs and then decreased to the lowest values in 24-DAH larvae. Changes in the protein amino acid (PAA) profile were much milder than those observed for FAAs. Most PAAs increased gradually during larval development, except lysine and phenylalanine. The percentages of free threonine, valine, isoleucine, and leucine decreased until the end of the trial, whereas the protein forms of these four AAs followed the opposite trend. A comparison of the essential AA composition of live food (rotifers, Artemia nauplii, and Artemia metanauplii) and larvae suggested that methionine was potentially the first limiting AA. These results may help develop starry flounder larviculture methods by solving the AA imbalance in live food. Moreover, the increased digestive enzyme activities indicate the possibility of introducing artificial compound feed.

  14. Structure and biodiversity of zooplankton communities in freshwater habitats of a Vereda Wetland Region, Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Olívia Penatti Pinese

    2015-09-01

    Full Text Available Abstract Aims: Vereda wetlands are among the most important aquatic habitats in Brazilian savannah (Cerrado because of their association with river springs and its relevancy for biodiversity conservation. This study aimed to determine and compare the biodiversity of zooplankton in vereda lakes, differentiated by the presence or absence of aquatic macrophytes at an environmental reserve in Uberlândia, Minas Geais, Southeastern Brazil. Zooplanctonic abundance patterns and their relation with environmental parameters were also discussed and presented through multivariate statistics. Methods Twelve samples were taken at water surface, at 15-day intervals in 2006. It was observed a total richness of 75 species, including 12 genera, 29 species and one sub-species as new records for Minas Gerais State. Results Rotifers were the predominant group and Lecanidae was the most diverse family. Among cladocerans, Chydoridae showed the greatest richness and Bosminidae the highest abundance. Few adult copepods were sampled in this study, but nauplii were very frequent. Cyclopidae was the most common family among copepods and there was no record of Calanoida. Conclusions The difference in composition among the studied lakes was remarkable. The lake with macrophytes showed the greatest richness but the lowest density, and the opposite situation occurred in the other lake. This can be explained by the fact that aquatic macrophytes, as primary producers, exert a bottom-up effect on zooplankton community, sustaining a high local diversity in contrast with a low numeric abundance of these microorganisms. Therefore, this pattern may have been created by the surround heterogeneity and, at the same time, by the reduction of available minerals of the system caused by macrophyte matter fixation. Many studies on zooplankton need to be developed in palm swamp communities in order to better comprehend the biological diversity and the energy balance in different habitats for

  15. Spatial variations in zooplankton diversity in waters contaminated with composite effluents

    Directory of Open Access Journals (Sweden)

    Asitava CHATTERJEE

    2007-08-01

    Full Text Available Zooplankton species are cosmopolitan in their clean freshwater habitat and are also found in industrial and municipal wastewaters. The present study records for the first time the aspects of zooplankton diversity in relation to physico-chemical environment of five selected sites of the East Calcutta wetlands, a Ramsar site of Kolkata city, India, heavily contaminated by industrial and municipal wastewaters. The study revealed the occurrence of 22 species of zooplankton, among these 3 species of Cladocera, 2 species of Copepoda, 15 species of Rotifera, and 2 species of Ostracoda were recorded. The copepod Mesocyclops leuckarti was found in all the five sites, rotifers Asplanchna brightwelli, Brachionus angularis, B. calyciflorus and Cladocera Ceriodaphnia cornuta were found in four sites; Moina micrura and Diaphanosoma sarsi were found at three sites. Site wise variation in dominance, diversity, evenness and richness were calculated. Site 1, a fish-pond that stabilized composite wastewater, showed the maximum species richness having 17 species, while Site 2, SWF wastewater carrying canal, showed only 4 species. The calculated Jack 1 values of Sites 1 to 5 were 21.78, 3.77, 18.63, 12.5 and 16.95 respectively. Shannon-Wiener species diversity index (H/ values were almost similar for all the three relatively less polluted sites viz, Site 1 (1.959, Site 4 (2.010, Site 5 (2.047. However, at highly polluted sites viz., 2 and 3, H/ value of 1.336 and 0.984 respectively, were calculated. Simpson’s Dominance index (Dsimp value was highest at Site 3 (0.618 indicating maximum dominance, whereas at Site 5 dominance was lowest (0.1680 and diversity was highest. We discuss the role of zooplankton in the amelioration of wastewater.

  16. Food habits of Juvenile American Shad and dynamics of zooplankton in the lower Columbia River

    Science.gov (United States)

    Haskell, C.A.; Tiffan, K.F.; Rondorf, D.W.

    2006-01-01

    As many as 2.4 million adult American shad annually pass John Day Dam, Columbia River to spawn upriver, yet food web interactions of juvenile shad rearing in John Day Reservoir are unexplored. We collected zooplankton and conducted mid-water trawls in McNary (June-July) and John Day reservoirs (August-November) from 1994 through 1996 during the outmigration of subyearling American shad and Chinook salmon. Juvenile American shad were abundant and represented over 98% of the trawl catch in late summer. The five major taxa collected in zooplankton tows were Bosmina longirostris, Daphnia, cyclopoid cope-pods, rotifers, and calanoid copepods. We evaluated total crustacean zooplankton abundance and Daphnia biomass in relation to water temperature, flow, depth, diel period, and cross-sectional location using multiple regression. Differences in zooplankton abundance were largely due to differences in water temperature and flow. Spatial variation in total zooplankton abundance was observed in McNary Reservoir, but not in John Day Reservoir. Juvenile American shad generally fed on numerically abundant prey, despite being less preferred than larger bodied zooplankton. A decrease in cladoceran abundance and size in August coupled with large percentages of Daphnia in juvenile American shad stomachs indicated heavy planktivory. Smaller juvenile American shad primarily fed on Daphnia in August, but switched to more evasive copepods as the mean size of fish increased and Daphnia abundance declined. Because Daphnia are particularly important prey items for subyearling Chinook salmon in mainstem reservoirs in mid to late summer, alterations in the cladoceran food base is of concern for the management of outmigrating salmonids and other Columbia River fishes. ?? 2006 by the Northwest Scientific Association. All rights reserved.

  17. The Lophotrochozoan TGF-β signalling cassette - diversification and conservation in a key signalling pathway.

    Science.gov (United States)

    Kenny, Nathan J; Namigai, Erica K O; Dearden, Peter K; Hui, Jerome H L; Grande, Cristina; Shimeld, Sebastian M

    2014-01-01

    TGF-β signalling plays a key role in the patterning of metazoan body plans and growth. It is widely regarded as a 'module' capable of co-option into novel functions. The TGF-β pathway arose in the Metazoan lineage, and while it is generally regarded as well conserved across evolutionary time, its components have been largely studied in the Ecdysozoa and Deuterostomia. The recent discovery of the Nodal molecule in molluscs has underlined the necessity of untangling this signalling network in lophotrochozoans in order to truly comprehend the evolution, conservation and diversification of this key pathway. Three novel genome resources, the mollusc Patella vulgata, annelid Pomatoceros lamarcki and rotifer Brachionus plicatilis, along with other publicly available data, were searched for the presence of TGF-β pathway genes. Bayesian and Maximum Likelihood analyses, along with some consideration of conserved domain structure, was used to confirm gene identity. Analysis revealed conservation of key components within the canonical pathway, allied with extensive diversification of TGF-β ligands and partial loss of genes encoding pathway inhibitors in some lophotrochozoan lineages. We fully describe the TGF-β signalling cassette of a range of lophotrochozoans, allowing firm inference to be drawn as to the ancestral state of this pathway in this Superphylum. The TGF-β signalling cascade's reputation as being highly conserved across the Metazoa is reinforced. Diversification within the activin-like complement, as well as potential wide loss of regulatory steps in some Phyla, hint at specific evolutionary implications for aspects of this cascade's functionality in this Superphylum. PMID:25690968

  18. Reproduction of two-spotted goby, Gobiusculus flavescens, in captivity

    Directory of Open Access Journals (Sweden)

    Vera Teles

    2014-06-01

    Full Text Available The two-spotted goby, Gobiusculus flavescens, is a common fish species along rocky shores in northern European waters. It is a small (40-60 mm, semipelagic marine fish, forming loose shoals in association with microalgae vegetation and mussel beds growing on the rock surface. It is a short-lived species, with a life span of 1-2 years. Both sexes display courtship behaviour and have sexual ornamentation during the breeding season. Male ornaments consist of large dorsal fins with iridescent blue lines, and iridescent blue spots along the sides of the body. Females develop a conspicuous, bright orange belly at sexual maturity. Due to these characteristics this species could have a great interest for ornamental aquariums. In previous work the maintenance of G. flavescens at high temperatures (until 23°C was successful. The aim of this study was to test the reproduction in captivity of G. flavescens. Six replicates were used (18L aquariums at the temperature of 18°C. In each replicate, two males and four females were introduced to an aquarium, where the males chose between two nests and courted the females. During the 112 days of the experiment the females spawned five times but only three spawns had success. The eggs take approximately 8 days to become mature. On the three spawns have hatched 300, 361 and 510 larvae at a time. The larvae were kept in a separate container and fed with alive rotifers and survived a maximum of 21 days. The reproduction of the two-spotted goby in captivity is possible at 18°C, but it is necessary to improve the conditions to rearing the larvae.

  19. 淀山湖浮游动物群落结构特征及其影响因子%Community Structure of Zooplankton and Influencing Factors in Dianshan Lake of Shanghai

    Institute of Scientific and Technical Information of China (English)

    李强; 田华; 姜民; 蔡文婕; 曹玥

    2015-01-01

    Dianshan Lake,located in the Taihu Lake basin at the border of Jiangsu Province and Shanghai City,is the largest natural freshwater lake in Shanghai.It is an important source of drinking water and is within the eco-conservation district of upstream Huangpu River.Over the past 10 years,with the rapid development of the regional economy,the waters of Dianshan Lake became eutrophic.Shanghai municipality took measures for bioremediation and endogenous pollution control to prevent algae blooms and eutrophication of Dianshan Lake has gradually im-proved.The ecosystem is recovering according to water monitoring data for Dianshan Lake from 2008 -2010.To better understand the zooplankton community in Dianshan Lake after ecological restoration,an investigation was conducted from March to December of 2013.Species composition and density,dominant species and biodiversity of rotifers and planktonic crustaceans were measured.After obtaining the data,the relationship of the zooplankton community structure was correlated with environmental factors including phytoplankton and water quality.The sam-ples were taken in March,June,September and December of 2013 at 12 sampling sites (S1 -S12):S1 -S3 loca-ted in the downstream section of Dianshan Lake;S6,S8 -S10 in the upstream section;S7 and S11 located in the open water zone;S4,S5 and S12 located near the east or west bank of the lake where the influence of inflow water was mild.Zooplankton samples for qualitative analysis were collected at 0.5 under the surface with No.25 plankton net,and fixed with 4% formalin.10 L water samples for quantitative analysis of copepods and cladocera were col-lected at 0.5 m with a No.25 net into a glass water sampler,and fixed with 4% formalin after concentration to 5 L.For quantitative analysis of rotifers,1 L water sample were collected at 0.5 m and,after shaking well,fixed with 4% formalin and Lugol′s solution and then concentrated to 50 mL by settling 24 h.All samples were taken to the laboratory

  20. Cultivation of Arthrospira (Spirulina platensis using confectionary wastes for aquaculture feeding

    Directory of Open Access Journals (Sweden)

    Hala Y. El-Kassas

    2015-12-01

    Full Text Available The microalga biomass production from confectionary effluent is a possible solution for the urgent need for a live food in aquaculture. Arthrospira (Spirulina platensis was the dominant alga in effluent of “Biscomisr a confectionary factory”, in Alexandria–Egypt. Therefore, it was isolated from the effluent samples and used throughout the study. The cyanobacterium, A. platensis was grown on the effluent using 22 Central Composite Design (22 CCD. This work addresses the best effluent dilution (WC, % as well as sodium bicarbonate concentration (SBC on the alga growth and biochemical composition. Total protein, carbohydrate, lipid contents and fatty acid profiles of the produced algal biomass were highly improved. The statistical analyses suggested that the main effect of (WC, % is significant negative influences on the algal contents of proteins, lipids and carbohydrates (p > 0.01. Although it had a significant positive influence on chlorophyll (p > 0.01, no significant effect on algal β carotenes (p > 0.05 had been reported. The inter action effect of SBC together with WC, % exerted a significant negative influence on the algal proteins (p > 0.01 and no significant effect on the other responses (p > 0.05. The produced alga biomass was used for feeding the rotifer, Brachionus plicatilis for further application in aquaculture. Growth rate, reproductive rate and fecundity attributes, fatty acid content of B. plicatilis were amended. The Pearson correlation test indicated that β carotenes displayed a highly positive significant correlation with the growth rate of B. plicatilis (r = 0.733, p < 0.01 and the carbohydrates showed significant positive correlations with Egg % (r = 0.657, p < 0.05.

  1. Effects of administration of probiotic strains on GALT of larval gilthead seabream: Immunohistochemical and ultrastructural studies.

    Science.gov (United States)

    Picchietti, Simona; Mazzini, Massimo; Taddei, Anna Rita; Renna, Raffaella; Fausto, Anna Maria; Mulero, Victoriano; Carnevali, Oliana; Cresci, Alberto; Abelli, Luigi

    2007-01-01

    Two bacterial strains Lactobacillus fructivorans (AS17B), isolated from adult seabream (Sparus aurata L.) gut, and Lactobacillus plantarum (906), isolated from human faeces, were administered contemporaneously during seabream development using Brachionus plicatilis and/or Artemia salina and dry feed as vectors. Experimental group A received the probiotic strains already via rotifers from day 5 post-hatch (ph), whereas treatment of group B began with Artemia feeding from day 27 ph. Fish were sampled at day 28 ph (group A and control) and day 99 ph (groups A, B and control) for electron microscopy, histology and immunohistochemistry with the polyclonal antiserum ORa against homologous serum Ig and the mAb G7 specific for seabream acidophilic granulocytes. In all groups, timing and pattern of differentiation of the digestive tract did not differ. Furthermore, neither tissue damage nor manifest inflammation was provoked by probiotic administration. At day 28 ph, the developing GALT already housed mucosal leucocytes, including Ig(+) cells but no acidophilic granulocytes. No differences were seen between experimental groups. At day 99 ph, the density of Ig(+) cells (+51%) and acidophilic granulocytes (+284%) was significantly higher (p<0.05) in group A than in controls. Also group B had a higher density of Ig(+) cells (+17%) and acidophilic granulocytes (+130%) compared with controls, although less pronounced. Light and electron microscopy observations detailed the occurrence of heterogeneous populations of lymphocytes and granulocytes in the developing intestinal mucosa, and highlighted the net expansion of G7(+) acidophilic granulocytes (A +536%, B +292% vs. control) due to probiotic administration. Evidence is provided that early feeding with probiotic-supplemented diet increased the number of Ig(+) cells and acidophilic granulocytes in seabream gut and that the effects were more pronounced when administration started during gut metamorphosis. These results point to a

  2. Interaction of species traits and environmental disturbance predicts invasion success of aquatic microorganisms.

    Directory of Open Access Journals (Sweden)

    Elvira Mächler

    Full Text Available Factors such as increased mobility of humans, global trade and climate change are affecting the range of many species, and cause large-scale translocations of species beyond their native range. Many introduced species have a strong negative influence on the new local environment and lead to high economic costs. There is a strong interest to understand why some species are successful in invading new environments and others not. Most of our understanding and generalizations thereof, however, are based on studies of plants and animals, and little is known on invasion processes of microorganisms. We conducted a microcosm experiment to understand factors promoting the success of biological invasions of aquatic microorganisms. In a controlled lab experiment, protist and rotifer species originally isolated in North America invaded into a natural, field-collected community of microorganisms of European origin. To identify the importance of environmental disturbances on invasion success, we either repeatedly disturbed the local patches, or kept them as undisturbed controls. We measured both short-term establishment and long-term invasion success, and correlated it with species-specific life-history traits. We found that environmental disturbances significantly affected invasion success. Depending on the invading species' identity, disturbances were either promoting or decreasing invasion success. The interaction between habitat disturbance and species identity was especially pronounced for long-term invasion success. Growth rate was the most important trait promoting invasion success, especially when the species invaded into a disturbed local community. We conclude that neither species traits nor environmental factors alone conclusively predict invasion success, but an integration of both of them is necessary.

  3. Vitamin A and arachidonic acid altered the skeletal mineralization in Atlantic cod (Gadus morhua) larvae without any interactions on the transcriptional level.

    Science.gov (United States)

    Lie, Kai Kristoffer; Kvalheim, Karen; Rasinger, Josef Daniel; Harboe, Torstein; Nordgreen, Andreas; Moren, Mari

    2016-01-01

    The main object of this study was to evaluate the impact of different levels of vitamin A (VA) and arachidonic acid (ARA) in relation to eicosapentaenoic acid (EPA) on mineralization and gene expression in Atlantic cod larvae (Gadus morhua). First-feeding larvae were fed enriched rotifers from start-feeding until 29 days post hatch (dph). Larvae in four tanks were fed one of the following diets: control (EPA/ARA ratio: 15.8, 0.9μg VA g(-1)), control+VA (EPA/ARA ratio: 15.8, 7.8μg VA g(-1)), High ARA (EPA/ARA ratio: 0.9, 1.5μg VA g(-1)) or High ARA+VA (EPA/ARA ratio: 0.9, 12.0μg VA g(-1)). Larvae fed High ARA+VA were shorter at 29dph compared to the other groups and had significantly less mineralized bones when comparing larvae of similar size, showing interaction effects between VA and ARA. Although transcriptomic analysis did not reveal any interaction effects, a higher number of genes were differentially expressed in the high ARA fed larvae compared to control+VA fed larvae. Furthermore, bglap1, bglap2 and col10a1 were all down-regulated in larvae fed High ARA-diets and to a greater extent than larvae fed VA supplemented diet, indicating an additive effect on mineralization. In conclusion, this study showed that the dietary increase in ARA and VA altered the skeletal metabolism during larval development, most likely through signaling pathways specific for each nutrient rather than an interaction. The present study also demonstrates that VA could affect the larval response to ARA, even within the accepted non-toxic/non-deficient range.

  4. Distribution and seasonal variability in the benthic eukaryotic community of Río Tinto (SW, Spain), an acidic, high metal extreme environment.

    Science.gov (United States)

    Aguilera, Angeles; Zettler, Erik; Gómez, Felipe; Amaral-Zettler, Linda; Rodríguez, Nuria; Amils, Ricardo

    2007-11-01

    The eukaryotic community of the Río Tinto (SW, Spain) was surveyed in fall, winter and spring through the combined use of traditional microscopy and molecular approaches, including Denaturing Gradient Gel Electrophoresis (DGGE) and sequence analysis of 18S rRNA gene fragments. Eukaryotic assemblages of surface sediment biofilms collected in January, May and September 2002 were compared from 13 sampling stations along the river. Physicochemical data revealed extremely acidic conditions (the pH ranged from 0.9 to 2.5) with high concentrations of heavy metals, including up to 20 mg l(-1) Fe, 317 mg l(-1) Zn, 47 mg l(-1) As, 42 mg l(-1) Cd and 4 mg l(-1) Ni. In total, 20 taxa were identified, including members of the Bacillariophyta, Chlorophyta and Euglenophyta phyla as well as ciliates, cercomonads, amoebae, stramenopiles, fungi, heliozoans and rotifers. In general, total cell abundances were highest in fall and spring but decreased drastically in winter, and the sampling stations with the most extreme conditions showed the lowest number of cells, as well as the lowest diversity. Species diversity did not vary much during the year. Only the filamentous algae showed a dramatic seasonal change, since they almost disappeared in winter and reached the highest biomass during the summer. Principal Components Analysis (PCA) showed a high inverse correlation between pH and most of the heavy metals analyzed, as well as Dunaliella sp., while Chlamydomonas sp. was directly related to pH during May and September. Three heavy metals (Zn, Cu and Ni) remained separate from the rest and showed an inverse correlation with most of the species analyzed, except for Dunaliella sp.

  5. Ecological impacts of filter-feeding Asian carps (Hypophthalmichthys spp. in Lake Balaton, Hungary

    Directory of Open Access Journals (Sweden)

    Gergely Boros

    2015-10-01

    Full Text Available Bighead carp (Hypophthalmichthys nobilis, silver carp (H. molitrix and their hybrids (collectively referred as Asian carps−AC are primarily planktivorous cyprinid fishes that have been introduced into more than 30 countries around the world, including Hungary. However, recent studies demonstrated that AC can adversely affect the water quality and native fish populations. In this study, we report on the rate of hybridization, growth parameters and feeding habits of AC, to assess their ecological impacts and life history traits in the oligo-mesotrophic Lake Balaton. We found that the majority of the investigated AC (n=116 were hybrids. In general, hybrid AC with silver carp characteristics dominated the stock (90%, but 10% of individuals exhibited bighead carp phenotype and the proportion of bighead carp genes exceeded 98% in 4 individuals. However, the variance in phenotypes and the rate of hybridization did not influence significantly the feeding habits. Rather, the food composition was determined by the availability of different food resources and the concentration of suspended inorganic particles in the ambient water. Stable isotope analyses and microscopic analyses of gut contents revealed that the vast majority (>99% of the ingested and metabolised food was zooplankton (mainly Rotifers, Cladocerans and Copepods. Despite the low proportions of algae in the food, we identified 155 phytoplankton taxa in the foregut-contents, among which there were several species (e.g., Scenedesmus spp. and Microcystis spp. that survived the passage through the guts. Growth rates of AC were intermediate in Lake Balaton, while their condition factors were relatively high compared with other ecosystems. The relatively high condition factors were particularly interesting in the light of the high inorganic matter content of ingested food (43±9% in dry mass. We conclude that the presence of AC is an ecological threat to Lake Balaton, because AC can be important

  6. Hydrocarbon-Degrading Bacteria Exhibit a Species-Specific Response to Dispersed Oil while Moderating Ecotoxicity.

    Science.gov (United States)

    Overholt, Will A; Marks, Kala P; Romero, Isabel C; Hollander, David J; Snell, Terry W; Kostka, Joel E

    2016-01-01

    The Deepwater Horizon blowout in April 2010 represented the largest accidental marine oil spill and the largest release of chemical dispersants into the environment to date. While dispersant application may provide numerous benefits to oil spill response efforts, the impacts of dispersants and potential synergistic effects with crude oil on individual hydrocarbon-degrading bacteria are poorly understood. In this study, two environmentally relevant species of hydrocarbon-degrading bacteria were utilized to quantify the response to Macondo crude oil and Corexit 9500A-dispersed oil in terms of bacterial growth and oil degradation potential. In addition, specific hydrocarbon compounds were quantified in the dissolved phase of the medium and linked to ecotoxicity using a U.S. Environmental Protection Agency (EPA)-approved rotifer assay. Bacterial treatment significantly and drastically reduced the toxicity associated with dispersed oil (increasing the 50% lethal concentration [LC50] by 215%). The growth and crude oil degradation potential of Acinetobacter were inhibited by Corexit by 34% and 40%, respectively; conversely, Corexit significantly enhanced the growth of Alcanivorax by 10% relative to that in undispersed oil. Furthermore, both bacterial strains were shown to grow with Corexit as the sole carbon and energy source. Hydrocarbon-degrading bacterial species demonstrate a unique response to dispersed oil compared to their response to crude oil, with potentially opposing effects on toxicity. While some species have the potential to enhance the toxicity of crude oil by producing biosurfactants, the same bacteria may reduce the toxicity associated with dispersed oil through degradation or sequestration. PMID:26546426

  7. Forest Management Intensity Affects Aquatic Communities in Artificial Tree Holes.

    Science.gov (United States)

    Petermann, Jana S; Rohland, Anja; Sichardt, Nora; Lade, Peggy; Guidetti, Brenda; Weisser, Wolfgang W; Gossner, Martin M

    2016-01-01

    Forest management could potentially affect organisms in all forest habitats. However, aquatic communities in water-filled tree-holes may be especially sensitive because of small population sizes, the risk of drought and potential dispersal limitation. We set up artificial tree holes in forest stands subject to different management intensities in two regions in Germany and assessed the influence of local environmental properties (tree-hole opening type, tree diameter, water volume and water temperature) as well as regional drivers (forest management intensity, tree-hole density) on tree-hole insect communities (not considering other organisms such as nematodes or rotifers), detritus content, oxygen and nutrient concentrations. In addition, we compared data from artificial tree holes with data from natural tree holes in the same area to evaluate the methodological approach of using tree-hole analogues. We found that forest management had strong effects on communities in artificial tree holes in both regions and across the season. Abundance and species richness declined, community composition shifted and detritus content declined with increasing forest management intensity. Environmental variables, such as tree-hole density and tree diameter partly explained these changes. However, dispersal limitation, indicated by effects of tree-hole density, generally showed rather weak impacts on communities. Artificial tree holes had higher water temperatures (on average 2°C higher) and oxygen concentrations (on average 25% higher) than natural tree holes. The abundance of organisms was higher but species richness was lower in artificial tree holes. Community composition differed between artificial and natural tree holes. Negative management effects were detectable in both tree-hole systems, despite their abiotic and biotic differences. Our results indicate that forest management has substantial and pervasive effects on tree-hole communities and may alter their structure and

  8. Artificial propagation of yellow spotted grunt, Plectorhinchus cinctus%花尾胡椒鲷的人工繁殖

    Institute of Scientific and Technical Information of China (English)

    周仁杰; 黄斌; 林涛

    2000-01-01

    A technique of artificially produced young yellow spotted grunt, Plectorhinchus cinctus from 13, March to 5, July in 1999 was reported. Total 3.0×104 tails of young fish with the average of total length 24.3mm and body weight O. 29g were obtained in this experiment. During the test period the natural temperature and salinity of seawater used in laboratory pools were 24.0-30.5 ℃ and 29.6-30.6 respectively. The feed processes for the larvae, juvenile and young fish are as follows: rotifer-artemia nauplii, and copepod, cladocera-minced fish meat. It is showed the death peek period occurs in post-juvenile at 38-44 day old.%报导了1999年5月13日至7月5日进行的花尾胡椒鲷人工育苗技术研究。培育获得平均全长24.3mm、平均体重0.29g的幼鱼鱼苗3.0万尾,育苗成活率达49.2%。试验期间室内育苗池水温与盐度的自然变化范围分别为24.0~30.5℃,29.6~30.5。仔、稚、幼鱼培育的饵料系列基本搭配为轮虫-卤虫无节幼体和桡足类、海水枝角类-鱼肉糜。试验发现:花尾胡椒鲷人工育苗的死亡高峰期出现在稚鱼后期,38~44日龄阶段。

  9. Macroinvertebrate communities and the relationships with biotic factors in river-connected lakes in the lower reaches of Yangtze River, China.

    Science.gov (United States)

    Chi, Shiyun; Zheng, Jinxiu; Zhao, Xianfu; Dong, Fangyong; Hu, Juxiang

    2016-10-01

    The relationships of macroinvertebrate communities with abiotic factors in lake and river system were well documented, but their relationships with biotic factors were few explored. The macroinvertebrate communities in two river-disconnected lakes (Poyang Lake and Shijiu Lake) and the rivers connected to Shijiu Lake were investigated to reveal the differences in communities and explore the relationships with biotic factors. A total of 34 species were recorded in the three water bodies. Combined with the previous study results, the dominant species in Poyang Lake is almost unchanged since 1997. Mollusks were dominated in abundance in Poyang Lake and the rivers connected to Shijiu Lake, while oligochaetes dominated the communities in Shijiu Lake. The alpha diversity indices of macroinvertebrates in Poyang Lake and the rivers connected to Shijiu Lake were distinctly higher than that of Shijiu Lake, and the beta diversity index of Shijiu Lake was the highest, supporting the rules that alpha diversity of macroinvertebrates achieves a maximum at a moderate level of connectivity and beta diversity seems to be higher when the connectivity is weaker. The differences in communities were significant between the Poyang Lake and Shijiu Lake, while the differences in the Poyang Lake and the rivers connected to Shijiu Lake were not significant. According to the results of canonical correspondence analysis (CCA), protozoon densities and phytoplankton biomass affected the distribution of macroinvertebrates in Shijiu Lake. Species number of planktonic crustaceans influenced the distribution of macroinvertebrates in rivers connected to Shijiu Lake, while species number of rotifer and densities of phytoplankton distinctly impacted on the distribution of macroinvertebrates in Poyang Lake. PMID:27650438

  10. Hydro biological Characteristics of Some Semi-intensive fish culture ponds of Lumding town of Nagaon district, Assam

    Directory of Open Access Journals (Sweden)

    Tapashi Gupta

    2013-04-01

    Full Text Available Hydrobiological assessment is useful for assessing the ecological quality of aquatic ecosystem since biological communities integrate the environmental effects of water chemistry. Ten fish ponds from Lumding town, which were under semi-intensive culture practice, were selected for hydrobiological investigations. Physico-chemical properties were studied for a period of two years from July 2009 to June 2011.Some selected parameters like pH, dissolve oxygen, free carbon dioxide, TDS , total alkalinity, total hardness, sp. Conductivity, transparency and BOD were studied on some fish pond water. P H ranges from 6.1 to8.5. Temperature ranges from 18 0 C-32 0 C. Color shows light green to dirty green. Transparency ranges 17-42cm, dissolve oxygen ranges from 3.2-8.0 ppm, total alkalinity ranges from 7.9-20.0ppm, Hardness ranges from 60-135 ppm, sp.conductance ranges from123-247µmhos/cm and BOD ranges from3.1-5.0ppm. The phytoplankton belonging to division Chlorophycae and Cyanophycae are predominant over the others and zooplanktons belonging to group Protozoa, Rotifers are predominant. . A total of 30 species of belonging to Chlorophycae. Cyanophycae were identified and a total of 20 species of Rotifera, 2 species of Cladocera and 1 genus of Copepods were found. The present study is expected to help achieve better and higher yield of fish by the fish farmer with increasing awareness regarding the hydrobiological feature of the pond and implement scientific management practices accordingly

  11. Toxicity of algal-derived aldehydes to two invertebrate species: Do heavy metal pollutants have a synergistic effect?

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Rebecca L. [School of Marine Science and Technology, University of Newcastle upon Tyne, Ridley Building, Claremont Road, Newcastle upon Tyne NE1 7RU (United Kingdom)]. E-mail: r.l.taylor@ncl.ac.uk; Caldwell, Gary S. [School of Marine Science and Technology, University of Newcastle upon Tyne, Ridley Building, Claremont Road, Newcastle upon Tyne NE1 7RU (United Kingdom); Bentley, Matthew G. [School of Marine Science and Technology, University of Newcastle upon Tyne, Ridley Building, Claremont Road, Newcastle upon Tyne NE1 7RU (United Kingdom)

    2005-08-15

    The recent discovery of the production of anti-proliferative aldehydes in a variety of microalgal species has lead to considerable investigation into the effects of these toxins on aquatic invertebrates. Studies have, however, rarely considered the impact pollutants may have on grazer responses to algal toxins. In this study, the acute toxicities of five aldehydes to the rotifer Brachionus plicatilis and nauplii of the brine shrimp Artemia salina are examined using immersion assays. In addition, the effect of a representative of these aldehydes in the presence of sub-lethal levels of heavy metals was examined. B. plicatilis generally showed greater sensitivity to the aldehydes than A. salina. The polyunsaturated 2-trans,4-trans-decadienal was the most toxic to both species having 24 h LD{sub 50} values of 7 and 20 {mu}M for B. plicatilis and A. salina, respectively. The remaining aldehydes had different orders of toxicity for the two species with a stronger relationship observed between mortality and aldehyde carbon-chain length for A. salina whereas B. plicatilis mortality showed a stronger dependence on the presence of carbon-carbon double bonds in the aldehydes. The presence of 1 {mu}M of copper sulphate in solutions of decadienal resulted in the reduction of the 24 h LD{sub 50} of decadienal by approximately a third for both species. 1 {mu}M of copper chloride in solutions of decadienal reduced the 24 h LD{sub 50} of decadienal to A. salina nauplii by approximately 11% and 1 {mu}M zinc sulphate caused a reduction of only 3%. Pre-exposure of the organisms to 1 {mu}M copper sulphate had no significant impact on their subsequent mortality in decadienal. The ecological implications and the possible mechanisms for the action of copper sulphate on the response of organisms to decadienal are discussed.

  12. First feed affects the expressions of microRNA and their targets in Atlantic cod.

    Science.gov (United States)

    Bizuayehu, Teshome Tilahun; Furmanek, Tomasz; Karlsen, Ørjan; van der Meeren, Terje; Edvardsen, Rolf Brudvik; Rønnestad, Ivar; Hamre, Kristin; Johansen, Steinar D; Babiak, Igor

    2016-04-14

    To our knowledge, there is no report on microRNA (miRNA) expression and their target analysis in relation to the type of the first feed and its effect on the further growth of fish. Atlantic cod (Gadus morhua) larvae have better growth and development performance when fed natural zooplankton as a start-feed, as compared with those fed typical aquaculture start-feeds. In our experiment, two groups of Atlantic cod larvae were fed reference feed (zooplankton, mostly copepods, filtered from a seawater pond) v. aquaculture feeds: enriched rotifers (Brachionus sp.) and later brine shrimp (Artemia salina). We examined the miRNA expressions of six defined developmental stages as determined and standardised by body length from first feeding for both diet groups. We found eight miRNA (miR-9, miR-19a, miR-130b, miR-146, miR-181a, miR-192, miR-206 and miR-11240) differentially expressed between the two feeding groups in at least one developmental stage. We verified the next-generation sequencing data using real-time RT-PCR. We found 397 putative targets (mRNA) to the differentially expressed miRNA; eighteen of these mRNA showed differential expression in at least one stage. The patterns of differentially expressed miRNA and their putative target mRNA were mostly inverse, but sometimes also concurrent. The predicted miRNA targets were involved in different pathways, including metabolic, phototransduction and signalling pathways. The results of this study provide new nutrigenomic information on the potential role of miRNA in mediating nutritional effects on growth during the start-feeding period in fish larvae. PMID:26857476

  13. Warming-induced changes in predation, extinction and invasion in an ectotherm food web.

    Science.gov (United States)

    Seifert, Linda I; Weithoff, Guntram; Gaedke, Ursula; Vos, Matthijs

    2015-06-01

    Climate change will alter the forces of predation and competition in temperate ectotherm food webs. This may increase local extinction rates, change the fate of invasions and impede species reintroductions into communities. Invasion success could be modulated by traits (e.g., defenses) and adaptations to climate. We studied how different temperatures affect the time until extinction of species, using bitrophic and tritrophic planktonic food webs to evaluate the relative importance of predatory overexploitation and competitive exclusion, at 15 and 25 °C. In addition, we tested how inclusion of a subtropical as opposed to a temperate strain in this model food web affects times until extinction. Further, we studied the invasion success of the temperate rotifer Brachionus calyciflorus into the planktonic food web at 15 and 25 °C on five consecutive introduction dates, during which the relative forces of predation and competition differed. A higher temperature dramatically shortened times until extinction of all herbivore species due to carnivorous overexploitation in tritrophic systems. Surprisingly, warming did not increase rates of competitive exclusion among the tested herbivore species in bitrophic communities. Including a subtropical herbivore strain reduced top-down control by the carnivore at high temperature. Invasion attempts of temperate B. calyciflorus into the food web always succeeded at 15 °C, but consistently failed at 25 °C due to voracious overexploitation by the carnivore. Pre-induction of defenses (spines) in B. calyciflorus before the invasion attempt did not change its invasion success at the high temperature. We conclude that high temperatures may promote local extinctions in temperate ectotherms and reduce their chances of successful recovery. PMID:25564019

  14. Diel vertical migration of predators (planktivorous fish larvae and prey (zooplankton in a tropical lagoon

    Directory of Open Access Journals (Sweden)

    Marcos Marques Mendonça

    2015-06-01

    Full Text Available ABSTRACT Based on the hypothesis that diel vertical migration (DVM is a mechanism of predator avoidance, the objective of the present study was to test for the occurrence of DVM in planktivorous fish larvae of Hypophthalmus edentatus (Spix, 1829 (Siluriformes, Pimelodidae and Plagioscion squamosissimus (Heckel, 1840 (Perciformes, Sciaenidae, and zooplankton (rotifers, cladocerans and copepods in an isolated tropical lagoon in the floodplain of the Upper Paraná River, Brazil (region of Parque Nacional de Ilha Grande. We investigated spatial overlap between predators (planktivorous fish larvae and prey (zooplankton, and tested which physical and chemical variables of the water are related to the DVM of the studied communities. We performed nocturnal (8:00 pm and 4:00 am and diurnal sampling (8:00 am and 4:00 pm in the limnetic region of the lagoon for six consecutive months, from October 2010 to March 2011, which comprises the reproductive period of the fish species analyzed. During the day the larvae tried to remain aggregated in the bottom of the lagoon, whereas at night they tried to disperse in the water column. Especially for cladocerans, the diel vertical migration is an important behavior to avoid predation larvae of H. edentatus and P. squamosissimus once decreased spatial overlap between secured and its potential predators, which corroborates the hypothesis that DVM is a mechanism of predator avoidance. Although significant correlations were observed between the abiotic factors and WMD of microcrustaceans at certain times of day, the effect of predation of fish larvae on zooplankton showed more important in this environment, because the small depth and isolation not allow great variation of abiotic factors seasonally and between strata the lagoon.

  15. Changes in digestive enzyme activities during larval development of Chinese loach Paramisgurnus dabryanus (Dabry de Thiersant, 1872).

    Science.gov (United States)

    Zhang, Yun-Long; Wu, Qiao-Wan; Hu, Wei-Hua; Wang, Fan; Zhao, Zhong-Bo; He, Hui; Shao, Wei-Han; Fan, Qi-Xue

    2015-12-01

    The digestive physiology of Chinese loach (Paramisgurnus dabryanus) was studied by assessing the specific and total activities of different pancreatic (trypsin, chymotrypsin, amylase and lipase), gastric (pepsin) and intestinal (alkaline phosphatase and leucine-aminopeptidase) enzymes from hatching to 40 days after hatching (DAH). Larvae were reared at 24.4 ± 0.4 °C and fed with rotifers from mouth opening (4 DAH) to 15 DAH, from 10 to 35 DAH with Cladocera and from 30 to 40 DAH with compound diet. Enzyme activities for trypsin, chymotrypsin, amylase and lipase were detected before the onset of exogenous feeding, indicating that these enzymes were genetically pre-programmed. Most of the pancreatic enzyme specific activities increased until 20 DAH and decreased thereafter. The pepsin activity of Chinese loach was firstly detected at 30 DAH, indicating the appearance of functional gastric gland. Alkaline phosphatase specific activity was detected from hatching onward, showed marked increase and reached the second peak at 20 DAH, while a gradual increase in specific leucine-aminopeptidase activity was observed until the end of the experiment. Accordingly, the larvae of Chinese loach possess a functional digestive system before the onset of exogenous feeding and the digestive capacity gradually increases as development progresses. The abrupt increase in intestinal enzyme activities between 10 and 20 DAH demonstrates onset of juvenile-like digestive mode in Chinese loach larvae. The increase in pepsin activity after 30 DAH indicates the shift from alkaline to acidic digestion in Chinese loach larvae, which may be considered as the onset of weaning. PMID:26232086

  16. 花鲈人工育苗技术的研究%Study on the Technique of Artificial Seeding Production of Lateolabrax japonicus

    Institute of Scientific and Technical Information of China (English)

    张美昭; 高天翔; 阮树会; 曲永琪; 王强; 苏纪宏

    2001-01-01

    Using fertilized eggs from parent fish cultivated artificially, 3 000 000 larval fish were hatched. At the cultivation condition of temperature 18~20℃ and tiny airing, 1 320 000 seeds of average total length 2.3cm were cultivated for 58 days, reared by microalage (Chrorella), fortified rotifer (Branchionus plicotilis), nauplii of artemia (Artemia salina), and compound microfeed of many different sizes. The survival rate of fry was as high as 64.1%, and the maximum quantity of seed reached 13 300/m3. Besides, there were 680 000 seeds of 1.3~1.9cm.%利用人工培育的亲鱼所获得的受精卵,孵化出仔鱼300万尾,在水温18~20℃、微充气的培育条件下,使用海水小球藻、轮虫、卤虫无节幼体和不同规格的微颗粒配合饲料进行饲喂,经58d培育出平均全长2.3cm的苗种132万尾,育苗成活率高达64.1%,单位水体最高出苗量达1.33万尾/m3;另外,还有1.3~1.9cm的苗种68万尾。

  17. Systematic analysis of microfauna indicator values for treatment performance in a full-scale municipal wastewater treatment plant.

    Science.gov (United States)

    Hu, Bo; Qi, Rong; Yang, Min

    2013-07-01

    The indicator values of microfauna functional groups and species for treatment performance were systematically evaluated based on the continuous monitoring of the entire microfauna communities including both protozoa and metazoa over a period of 14 months, in two parallel full-scale municipal wastewater treatment systems in a plant in Beijing, China. A total of 57 species of ciliates, 14 species (units) of amoebae, 14 species (units) of flagellates and 4 classes of small metazoa were identified, with Arcella hemisphaerica, Vorticella striata, Vorticella convallaria, Epistylis plicatilis and small flagellates (e.g. Bodo spp.) as the dominant protozoa, and rotifers as the dominant metazoa. The abundance of the sessile ciliates was correlated with the removals of BOD5 (Pearson's r = 0.410, p < 0.05) and CODcr (r = 0.397, p < 0.05) while the testate amoebae was significantly positively related to nitrification (r = 0.523, p < 0.01). At the same time, some other associations were also identified: the abundances of the large flagellates (r = 0.447, p < 0.01), the metazoa (r = 0.718, p < 0.01) and species Aspidisca sulcata (r = 0.337, p < 0.05) were positively related to nitrification; the abundance of Aspidisca costata was correlated to the TN (total nitrogen) removal (r = -0.374, p < 0.05 ); the abundances of the sessile species Carchesium polypinum (r = 0.458, p < 0.01) and E. plicatilis (r = 0.377, p < 0.05) were correlated with the removal of suspended solids. PMID:24218850

  18. Examination of a Smallest CELSS (Microcosm) Through an Individual- Based-Model Simulation

    Science.gov (United States)

    Ishikawa, Y.; Sugiura, K.

    Research of the effect of space environment on an ecosystem consisting of plants and animals is essential when they are to be positively used in space. Although there have been experiments on various organisms under space environment in the past, they mainly studied the effect of space environment on an individual organism or a single species. Microcosm is drawing attention as an experimental material of an ecosystem consisting of multiple species. The object in this research is to understand the nature of this network system called ecosystem. Thus, a mixed microorganism culturing system consisting of three types of microorganisms (chlorella, bacteria, and rotifer) which form a minimum food chain system as a closed ecosystem was taken for the subject, on which the universal characteristics of ecosystems is searched. From the results of experiments under earth environment, formation of colonies, which is an ecological structure, has been observed at its mature stage. Therefore, formation of colonies in simulation models is important. For example, the Lotka- Volterra model forms a system of the differential equations expressing predator and prey relationship and many numerical calculations have been conducted to various ecosystems based on expanded L-V models. Conventionally, these top-down methods have been used. However, since this method only describes the average concentration of organisms that are distributed uniformly throughout the system and cannot express the spatial structure of the system, it was difficult to express the ecosystem structures like colonies and substance density distribution. In actual ecosystems, there is heterogeneity in the number of individuals and in substance density, and this is thought to have great significance in ecosystems. Consequently, an Individual-Based-Model was used to give rules to predator-prey relationship, suppression, production, self suppression, etc. of each species. It enabled the emergence of the overall system only

  19. Diapause and maintenance of facultative sexual reproductive strategies.

    Science.gov (United States)

    Stelzer, Claus-Peter; Lehtonen, Jussi

    2016-10-19

    Facultative sex combines sexual and asexual reproduction in the same individual (or clone) and allows for a large diversity of life-history patterns regarding the timing, frequency and intensity of sexual episodes. In addition, other life-history traits such as a diapause stage may become linked to sex. Here, we develop a matrix modelling framework for addressing the cost of sex in facultative sexuals, in constant, periodic and stochastically fluctuating environments. The model is parametrized using life-history data from Brachionus calyciflorus, a facultative sexual rotifer in which sex and diapause are linked. Sexual propensity was an important driver of costs in constant environments, in which high costs (always > onefold, and sometimes > twofold) indicated that asexuals should outcompete facultative sexuals. By contrast, stochastic environments with high temporal autocorrelation favoured facultative sex over obligate asex, in particular, if the penalty to fecundity in 'bad' environments was large. In such environments, obligate asexuals were constrained by their life cycle length (i.e. time from birth to last reproductive adult age class), which determined an upper limit to the number of consecutive bad periods they could tolerate. Nevertheless, when facultative asexuals with different sexual propensities competed simultaneously against each other and asex, the lowest sex propensity was the most successful in stochastic environments with positive autocorrelation. Our results suggest that a highly specific mechanism (i.e. diapause linked to sex) can alone stabilize facultative sex in these animals, and protect it from invasion of both asexual and pure sexual strategies.This article is part of the themed issue 'Weird sex: the underappreciated diversity of sexual reproduction'. PMID:27619700

  20. Temperature Effect on the Life History of Three Types of Brachionus calyciflorus Females

    Institute of Scientific and Technical Information of China (English)

    席贻龙; 黄祥飞

    2004-01-01

    The effect of temperature on the life history characteristics of amictic females (AF), unfertilized mictic females (UMF) and fertilized mictic females (FMF) in Brachionus calyciflorus was studied with replicated individual cultures at 20℃,25℃ and 30℃, and with algae Scenedesmus obliquus for their food. There were highly significant effects of both temperature and female type, independently and interactively, on the duration of juvenile and post-reproduction periods, and the number of eggs produced by the rotifer per life cycle. Among all the temperature-female type combinations, all the juvenile periods of FMF, and the post-reproduction periods of UMF and FMF at 20℃, were the longest, and the number of eggs produced by an UMF at 30℃ was the highest. There were highly significant effects of both temperature and female type on the duration of the reproduction period, but no clear correlation was observed between temperature and female type. The reproduction period of AF was longer than that of UMF and FMF. Only temperature influenced significantly the mean life-span of the three types of females. The duration of juvenile, reproduction and post-reproduction periods as well as the life-span of the three types of females were all reduced very significantly with rise of temperature, but the rates of reduction varied with female type. Among the three types of females, the number of eggs produced per life cycle by an UMF was the highest, and that of a FMF was the lowest. A significant relationship between the number of eggs produced per life cycle and temperature was observed only in the UMF.

  1. The microbial community of Ophrydium versatile colonies: endosymbionts, residents, and tenants

    Science.gov (United States)

    Duval, B.; Margulis, L.

    1995-01-01

    Ophrydium versatile is a sessile peritrichous ciliate (Kingdom Protoctista, class Oligohymenophora, order Peritrichida, suborder Sessilina) that forms green, gelatinous colonies. Chlorophyll a and b impart a green color to Ophrydium masses due to 400-500 Chlorella-like endosymbionts in each peritrich. Ophrydium colonies, collected from two bog wetlands (Hawley and Leverett, Massachusetts) were analyzed for their gel inhabitants. Other protists include ciliates, mastigotes, euglenids, chlorophytes, and heliozoa. Routine constituents include from 50-100,000 Nitzschia per ml of gel and at least four other diatom genera (Navicula, Pinnularia, Gyrosigma, Cymbella) that may participate in synthesis of the gel matrix. Among the prokaryotes are filamentous and coccoid cyanobacteria, large rod-shaped bacteria, at least three types of spirochetes and one unidentified Saprospira-like organism. Endosymbiotic methanogenic bacteria, observed using fluorescence microscopy, were present in unidentified hypotrichous ciliates. Animals found inside the gel include rotifers, nematodes, and occasional copepods. The latter were observed in the water reservoir of larger Ophrydium masses. From 30-46% of incident visible radiation could be attenuated by Ophrydium green jelly masses in laboratory observations. Protargol staining was used to visualize the elongate macronuclei and small micronucleus of O. versatile zooids and symbiotic algal nuclei. Electron microscopic analysis of the wall of the Chlorella-like symbiont suggests that although the Ophrydium zooids from British Columbia harbor Chlorella vulgaris, those from Hawley Bog contain Graesiella sp. The growth habit in the photic zone and loose level of individuation of macroscopic Ophrydium masses are interpretable as extant analogs of certain Ediacaran biota: colonial protists in the Vendian fossil record.

  2. Plancto e hidrobiologia sanitária de tanques tropicais com dáfnias e rotíferos

    Directory of Open Access Journals (Sweden)

    Lejeune P. H. de Oliveira

    1967-01-01

    NH[4 subscripted]. b Species of the genus Chlamydomonas; it is even possible that all the species of theses genus inhabit strong-mesosaprobic to polysaprobic waters when in massive blooms. c Several species of Euglenaceae in fast growing number, at the same time of the protozoa Amoebidae, Vorticellidae and simultaneous with deposition of the decaying cells of the blue algae Anacystis cyanea (= Microcystis when the consumed oxygen by organic matter resulted in 40 mg. L. But, we found, among various Euglenacea the cosmopolite species (Euglena viridis, a well known polysaprobic indicatior of which presence occur in septic zone. d Analcystis cyanea (= M. aeruginosa as we observed was in blooms increasing to the order of billions of cells per litter, its maximum in the summer. Temperatures 73ºF to 82ºF but even 90ºF, the pH higher than 8. When these blue algae was joined to the rotifer Brachionus calyflorus the waters gets a milky appearance, but greenished one. In fact, that cosmopolite algae is used as a mesosaprobic indicator. Into the water of the ponds its predominance finished when the septic polysaprobic conditions began. e Ankistrodesmus falcatus was present in the 5th pond from 26the. April untill the 26th July, and when N.NH[4 subscripted] gets 1.28 mg. L. and when chlorinity stayed from 0.034 to 0.061 mg. L. It never was found at N.NH[4 subscripted] higher than 1 mg. L. The green algae A. falcatus, an indicatior of pollution, lives in moderate mesosaprobic waters. f As everyone knows, the rotifer eggs may be widely dispersed by wind. The rotifer Asplanchna brightwelli in our observation seemed like a green colored bag, overcharged by green cells and detritus, specially into its spacious stomach, which ends blindly (the intestine, cloaca, being absent. The stock of Asplanchna in the ponds, during the construction of the bridge "PONTE OSWALDO CRUZ" inhabits alkaline waters, pH 8,0 a 8,3, and when we observed we noted its dissolved oxygen from 3.5 to 4 mg. L

  3. Controls on microalgal community structures in cryoconite holes upon high-Arctic glaciers, Svalbard

    Science.gov (United States)

    Vonnahme, T. R.; Devetter, M.; Žárský, J. D.; Šabacká, M.; Elster, J.

    2016-02-01

    Glaciers are known to harbor surprisingly complex ecosystems. On their surface, distinct cylindrical holes filled with meltwater and sediments are considered hot spots for microbial life. The present paper addresses possible biological interactions within the community of prokaryotic cyanobacteria and eukaryotic microalgae (microalgae) and relations to their potential grazers, such as tardigrades and rotifers, additional to their environmental controls. Svalbard glaciers with substantial allochthonous input of material from local sources reveal high microalgal densities. Small valley glaciers with high sediment coverages and high impact of birds show high biomasses and support a high biological diversity. Invertebrate grazer densities do not show any significant negative correlation with microalgal abundances but rather a positive correlation with eukaryotic microalgae. Shared environmental preferences and a positive effect of grazing are the proposed mechanisms to explain these correlations. Most microalgae found in this study form colonies ( 25 µm), which may protect them against invertebrate grazing. This finding rather indicates grazing as a positive control on eukaryotic microalgae by nutrient recycling. Density differences between the eukaryotic microalgae and prokaryotic cyanobacteria and their high distinction in redundancy (RDA) and principal component (PCA) analyses indicate that these two groups are in strong contrast. Eukaryotic microalgae occurred mainly in unstable cryoconite holes with high sediment loads, high N : P ratios, and a high impact of nutrient input by bird guano, as a proxy for nutrients. In these environments autochthonous nitrogen fixation appears to be negligible. Selective wind transport of Oscillatoriales via soil and dust particles is proposed to explain their dominance in cryoconites further away from the glacier margins. We propose that, for the studied glaciers, nutrient levels related to recycling of limiting nutrients are the

  4. TAXAS DE FILTRAÇÃO E INGESTÃO DE UMA MICROALGA POR Philodina roseola (Rotifera: Bdelloidea

    Directory of Open Access Journals (Sweden)

    Raquel Aparecida Moreira

    2016-04-01

    and organic productivity of freshwater ecosystems due to their high metabolic rates. Information on filter feeding, their main process of energy acquisition, are relevant and still scarce for tropical regions. The rotifers of the class Bdelloidea feed by filtration or scraping consuming small food items, such as bacteria, algae, yeasts or particulate organic matter. We know little of their role in the trophic dynamics in the habitats they occupy and so the aim of this study was to quantify laboratory filtration and ingestion rates of the rotifer Philodina roseola, fed with Raphidocelis subcapitata. The experiment consisted of 10 adult exposure treatment at five concentrations approximately in the range between 104 and 107 cells mL-1, at the temperature of 25 ± 1 °C. The experiments lasted one hour and initial and final concentrations of the algal suspensions were determined by counting the number of cells in a Neubauer chamber. There were no significant differences between the initial and final concentrations of cells in the control group indicating that algal growth did not occur. Philodina roseola filtration rates varied between 0.09 and 0.25 mL ind-1 h-1. Given that filtration is the main process of energy acquisition by Philodina roseola, as well as for most other rotifers, and that it comprises important issues related to trophic dynamics of aquatic ecosystems, additional experimental information is especially important and need to be extended to other types of food and combinations of experimental conditions.Tasas de filtración e ingestión de una microalga por Philodina roseola (Rotifera: BdelloideaRESUMENLos rotíferos desempeñan un importante papel en los ciclos biogeoquímicos y en la productividad orgánica de los ecosistemas de agua dulce como consecuencia de sus elevadas tasas metabólicas. Es relevante la información sobre la filtración, su principal proceso de adquisición de energía, la cual es todavía escasa para la región tropical. Los rot

  5. 小鹤立河水库春季浮游动物群落特征及其与环境因子的相关性%The Community Structure and Environmental Correlation of Zooplankton in Xiaoheli River Reservoir during Spring

    Institute of Scientific and Technical Information of China (English)

    李秀媛; 于洪贤

    2013-01-01

    2012年5月在小鹤立河水库设置了7个采样点,研究了小鹤立河水库中浮游动物种类组成及其与环境因子的关系.在小鹤立河水库共鉴定出浮游动物15种,其中原生动物6种,占浮游动物总物种数的40.0%;轮虫8种,占53.3%;枝角类1种,占6.6%;浮游动物丰度变动幅度为77 ~ 683ind.·L-1.香农-威纳多样性指数最高和最低分别出现在5#和7#,分别为1.94和1.28.Pearson相关性分析结果显示:小鹤立河水库浮游动物丰度与水深、溶解氧量、总氮含量显著相关(P<0.05).%The zooplankton species composition and relation to the environment were studied in 7 sampling sites in Xiaoheli River Reservoir in Heilongjiang Province during May of 2012. A total of 15 zooplankton species were recorded including 6 species of protozoa, 8 species of rotifer and 1 species of cladoceran. The zooplankton abundance was shown to be ranged from 77 ind.·L-1 to 683 ind.. ·L-1. There were the peak Shannon Wiener diversity ind.ex( 1.94) in sampling site 5 and the minimal value (1.28) in sampling site 7. The Pearson correlation analysis revealed that water depth, dissolved oxygen levels (DO) and the concentrations of TN were closely correlated with the zooplankton abundance(P<0.05).

  6. Constructional Characteristics of Zooplankton Community at Longtan Reservoir of the Hongshui River%红水河龙滩水库浮游动物群落结构特征

    Institute of Scientific and Technical Information of China (English)

    方艳红; 常秀玲; 黄道明; 梁银铨; 赵莎莎; 谢文星; 杨汉运

    2011-01-01

    2009年夏季和冬季对龙滩水库浮游动物进行了2次调查,共检出浮游动物73属、137种;夏季为100种,冬季为108种;夏季优势种10种,冬季优势种11种,两季共有的优势种为6种。浮游动物平均密度为5 800个/L,原生动物占绝对优势;平均生物量为1.2366 mg/L,轮虫所占比重最大。两季浮游动物现存量无明显差异,但在水平分布上差异显著。依据浮游动物密度聚类分析,龙滩水库各断面浮游动物分为3大类群。龙滩水库成库后,库尾段浮游动物现存量变化较小,坝前、库中明显增加。依据浮游动物生态学指标评价,龙滩水库水质为贫-中营养型。%A preliminary survey of zooplanktons was made in the summer and winter of 2009 at Longtan Reservoir, and the result indicated that the reservoir harbored 137 species of zooplanktons falling into 73 genus, respectively 100 species in summer with 10 species of dominant species and 108 in winter with 11 dominant species, 6 dominant species in both summer and winter, and that the average density of zooplanktons was 5800 pieces/L, with protozoa in dominant; average biomass is 1. 2366 mg/L, with rotifers in the largest proportion. Zooplankton biomass was of no significant difference in summer and winter; but horizontal distributions varied obviously. A cluster analysis of zooplanktons demonstrated that the reservoir encompassed 3 class groups of zooplanktons at all sections. The standing crop of zooplanktons less varied at the final section of Longtan Reservoir, but significantly rose in front of the dam and in the middle of the reservoir. Evaluation of zooplankton ecological index showed that the water quality at Longtan Reservoir was that of poor - medium nutrition status.

  7. Protozoan Community Diversity in Membrane Bioreactor%膜生物反应器系统中原生动物的群落特征

    Institute of Scientific and Technical Information of China (English)

    郑祥; 刘俊新

    2009-01-01

    与常规生物处理工艺相比,膜生物反应器(MBR)系统由于污泥停留时间长、污泥浓度高等特点,因此反应器内微生物种群结构呈现不同的特点.通过对MBR系统中原生动物的群落结构进行为期近2年连续的监测结果表明,过长的污泥龄对系统中原生动物的种类与数量均有负面的影响.研究发现:①在长期不排泥的MBR系统中,当环境温度从11℃上升到25℃,原生动物的多样性呈显著上升趋势;②当污泥龄从350 d下降到30 d,MBR系统中原生动物的种类与数量明显增加.特别在较低的环境温度条件下,系统中原生动物的种类与数量随着污泥龄的缩短呈显著的上升趋势;③与相同污泥龄(SRT=30d)的氧化沟(TOD)系统相比,MBR的污泥中原生动物的种类与数量均低于TOD.%Continuous monitoring on the microbial character was performed in the sludge in MBR compared with traditional active sludge process. It was found that the sludge retention time (SRT) and temperature were the dominant factors that control protozoan diversity. The extra-long SRT exhibited a negative effect on the activity of protozoa. When SRT decreased from 350 d to 30 d, protozoan diversity increased significantly. Subsequently, the structure of protozoa community in the MBR was found to be quite sensitive to environment temperature, and protozoan diversity continuously increased with the increasing temperature from 11 to 25℃ . The dominant population was alternate and in some order: running Ciliata , Epistylis and Opercularia, Rotifers , then Aeolosomatidae . Further analysis showed that MBR reactor harbored a lower detectable microbial diversity compared with the TOD reactor at the same temperature and SRT.

  8. Allelopathic effects of microcystin-LR on the germination, growth and metabolism of five charophyte species and a submerged angiosperm.

    Science.gov (United States)

    Rojo, Carmen; Segura, Matilde; Cortés, Francisco; Rodrigo, María A

    2013-11-15

    Microcystins (MCs) are produced by cyanobacteria in aquatic environments and adversely affect macrophytes at very high concentrations. However, the effects of MC on macrophytes at concentrations of environmental relevance are largely unknown. The main objective of this study was to analyze the allelopathic effects of MC-LR at natural concentrations (1, 8 and 16 μg MC-LR/L) on five charophyte species (Chara aspera, C. baltica, C. hispida, C. vulgaris and Nitella hyalina) and the angiosperm Myriophyllum spicatum. Macrophyte specimens were obtained from a restored area located in Albufera de València Natural Park, a protected coastal Mediterranean wetland. Two different experiments were conducted involving (i) the addition of MC-LR to natural sediment to evaluate its effects on seed germination and (ii) the addition of MC-LR to water cultures of macrophytes to evaluate its effects on growth and metabolic functions. In water, the MC-LR concentration decreased by 84% in two weeks; the loss was not significant in sediment. The first seedlings (all C. hispida) emerged from the wetland sediment following a delay of a few days in the presence of MC-LR. The germination rates in 8 and 16 μg MC-LR/L treatments were 44% and 11% of that occurring in the absence of MC, but these differences disappeared over time. The final density was 6-7 germlings/dm(3). Final germling length was unaffected by MC-LR. Rotifers (Lecane spp.) emerging from the natural sediment during the experiment were favored by MC-LR; the opposite pattern was observed in the cladoceran Daphnia magna. The growth rates of C. vulgaris, C. baltica and N. hyalina were unaffected by MC exposure, whereas those of C. hispida and C. aspera were reduced in the MC treatments relative to the control treatment. The concentration of chlorophyll-a and the in vivo net photosynthetic rate were lower in the presence of MC-LR, even at the lowest concentration, for all of the characeans tested. M. spicatum was sensitive to the

  9. Synergy in microcosms with environmentally realistic concentrations of prochloraz and esfenvalerate.

    Science.gov (United States)

    Bjergager, Maj-Britt A; Hanson, Mark L; Lissemore, Linda; Henriquez, Nikki; Solomon, Keith R; Cedergreen, Nina

    2011-01-25

    Laboratory experiments have shown that azole fungicides enhance the toxic effect of pyrethroid insecticides towards the aquatic crustacean Daphnia magna. Due to their sorptive properties the pesticides may, however, be less bioavailable in natural environments, possibly rendering them less toxic to aquatic organisms. In the present study, the synergistic potential of azoles on pyrethroids in natural environments was assessed by treating 18 outdoor aquatic microcosms with concentrations of the pyrethroid esfenvalerate at 0.167, 0.333, or 0.833μg/L either alone or in combination with 90μg/L of the azole prochloraz. Pesticide concentrations and the zooplankton and phytoplankton communities were assessed prior to pesticide application and at days 0, 1, 2, 4, 7, 14, 21, and 28 after pesticide application. DT(50)-values for disappearance of the pesticides from the water of 4.7 days and 30h were observed for prochloraz and esfenvalerate, respectively. The monitored communities showed larger decreases in abundance of cladoceran, copepods, and chironomids in treatments with esfenvalerate in combination with prochloraz compared to treatments with esfenvalerate alone. No systematic effects were observed in populations of Ostracoda. Adverse effects on populations of cladocerans and copepods occurred between day 2 and day 7 and, though copepods in general were less sensitive than cladocerans to both esfenvalerate alone and in combination with prochloraz, the potentiation factors for the two taxa were similar. Thus, comparison of EC(20)-values estimated on the basis of concentration-response curves for days 2, 4, and 7 showed that prochloraz enhanced the toxicity of esfenvalerate four to sixfold for copepods and three to sevenfold for cladocerans. Rotifers were not significantly affected by any of the treatments, though there was a tendency of a population increase when cladoceran and copepod populations decreased. In all invertebrate populations that showed response to the

  10. The chronic toxicity of molybdate to freshwater organisms. I. Generating reliable effects data

    Energy Technology Data Exchange (ETDEWEB)

    De Schamphelaere, K.A.C., E-mail: karel.deschamphelaere@Ugent.be [Laboratory of Environmental Toxicology and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University (Belgium); Stubblefield, W. [Oregon State University, Department of Environmental and Molecular Toxicology, 421 Weniger Hall, Corvallis, OR 97331 (United States); Rodriguez, P. [Centro de Investigacion Minera y Metalurgica (CIMM), Santiago (Chile); Vleminckx, K. [Department for Molecular Biomedical Research, Ghent University (Belgium); Janssen, C.R. [Laboratory of Environmental Toxicology and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University (Belgium)

    2010-10-15

    The European Union regulation on Registration, Evaluation, Authorization and Restriction of Chemical substances (REACH) (EC, 2006) requires the characterization of the chronic toxicity of many chemicals in the aquatic environment, including molybdate (MoO{sub 4}{sup 2-}). Our literature review on the ecotoxicity of molybdate revealed that a limited amount of reliable chronic no observed effect concentrations (NOECs) for the derivation of a predicted no-effect concentration (PNEC) existed. This paper presents the results of additional ecotoxicity experiments that were conducted in order to fulfill the requirements for the derivation of a PNEC by means of the scientifically most robust species sensitivity distribution (SSD) approach (also called the statistical extrapolation approach). Ten test species were chronically exposed to molybdate (added as sodium molybdate dihydrate, Na{sub 2}MoO{sub 4}.2H{sub 2}O) according to internationally accepted standard testing guidelines or equivalent. The 10% effective concentrations (EC10, expressed as measured dissolved molybdenum) for the most sensitive endpoint per species were 62.8-105.6 (mg Mo)/L for Daphnia magna (21 day-reproduction), 78.2 (mg Mo)/L for Ceriodaphnia dubia (7 day-reproduction), 61.2-366.2 (mg Mo)/L for the green alga Pseudokirchneriella subcapitata (72 h-growth rate), 193.6 (mg Mo)/L for the rotifer Brachionus calyciflorus (48 h-population growth rate), 121.4 (mg Mo)/L for the midge Chironomus riparius (14 day-growth), 211.3 (mg Mo)/L for the snail Lymnaea stagnalis (28 day-growth rate), 115.9 (mg Mo)/L for the frog Xenopus laevis (4 day-larval development), 241.5 (mg Mo)/L for the higher plant Lemna minor (7 day-growth rate), 39.3 (mg Mo)/L for the fathead minnow Pimephales promelas (34 day-dry weight/biomass), and 43.2 (mg Mo)/L for the rainbow trout Oncorhynchus mykiss (78 day-biomass). These effect concentrations are in line with the few reliable data currently available in the open literature. The data

  11. The chronic toxicity of molybdate to freshwater organisms. I. Generating reliable effects data.

    Science.gov (United States)

    De Schamphelaere, K A C; Stubblefield, W; Rodriguez, P; Vleminckx, K; Janssen, C R

    2010-10-15

    The European Union regulation on Registration, Evaluation, Authorization and Restriction of Chemical substances (REACH) (EC, 2006) requires the characterization of the chronic toxicity of many chemicals in the aquatic environment, including molybdate (MoO(4)(2-)). Our literature review on the ecotoxicity of molybdate revealed that a limited amount of reliable chronic no observed effect concentrations (NOECs) for the derivation of a predicted no-effect concentration (PNEC) existed. This paper presents the results of additional ecotoxicity experiments that were conducted in order to fulfill the requirements for the derivation of a PNEC by means of the scientifically most robust species sensitivity distribution (SSD) approach (also called the statistical extrapolation approach). Ten test species were chronically exposed to molybdate (added as sodium molybdate dihydrate, Na(2)MoO(4)·2H(2)O) according to internationally accepted standard testing guidelines or equivalent. The 10% effective concentrations (EC10, expressed as measured dissolved molybdenum) for the most sensitive endpoint per species were 62.8-105.6 (mg Mo)/L for Daphnia magna (21day-reproduction), 78.2 (mg Mo)/L for Ceriodaphnia dubia (7day-reproduction), 61.2-366.2 (mg Mo)/L for the green alga Pseudokirchneriella subcapitata (72h-growth rate), 193.6 (mg Mo)/L for the rotifer Brachionus calyciflorus (48h-population growth rate), 121.4 (mg Mo)/L for the midge Chironomus riparius (14day-growth), 211.3 (mg Mo)/L for the snail Lymnaea stagnalis (28day-growth rate), 115.9 (mg Mo)/L for the frog Xenopus laevis (4day-larval development), 241.5 (mg Mo)/L for the higher plant Lemna minor (7day-growth rate), 39.3 (mg Mo)/L for the fathead minnow Pimephales promelas (34day-dry weight/biomass), and 43.2 (mg Mo)/L for the rainbow trout Oncorhynchus mykiss (78day-biomass). These effect concentrations are in line with the few reliable data currently available in the open literature. The data presented in this study can

  12. L'élevage larvaire des poissons marins : chaînes alimentaires et aliments composés

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    GIRIN M.

    1977-01-01

    Full Text Available L'approvisionnement quotidien en nourriture est, en règle générale, le principal facteur limitant de productions à grande échelle de jeunes poissons marins.La pêche de plancton dans la nature a été, et reste, le moyen d'expérimentation le plus immédiat, et le plus satisfaisant sur le plan qualitatif. Mais la récolte des quantités nécessaires, au moment voulu, devient très délicate dès que l'on dépasse l'échelle de l'aquarium. Le développement, ces dernières décennies, de techniques de production en masse d'animaux-proies a permis le lancement d'élevages à grande échelle. Parmi ces proies, le Branchiopode Artemia salina et le Rotifère Brachionus plicatilis dominent incontestablement ; tandis que l'élevage des Copépodes, part la plus intéressante du plancton naturel, reste encore mal maîtrisé. Cependant , l'élevage et l'emploi de proies vivantes, quelles qu'elles soient, imposent la réalisation d'installations coûteuses et l'emploi d'un abondant personnel qualifié. Il en est résulté récemment un important effort de recherche en direction de nourritures inertes, broyats , poudres et aliments composés, généralement abandonnés après les échecs enregistrés pendant les premières années du siècle. Quelques résultats encourageants ont été obtenus, mais ils restent limités et soulèvent de délicats problèmes d'hygiène des bacs d'élevage. L'emploi de proies vivantes , au moins pendant le premier mois des élevages , reste donc encore une obligation. Dans ce contexte, l'essentiel de l'effort actuel tend , d'une part à réduire leur durée d'emploi au minimum possible et, d'autre part, à rendre leur production plus rationnelle , en recherchant des méthodes qui évitent, pour leur alimentation , de faire appel à des algues planctoniques vivantes.

  13. The mate recognition protein gene mediates reproductive isolation and speciation in the Brachionus plicatilis cryptic species complex

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    Gribble Kristin E

    2012-08-01

    Full Text Available Abstract Background Chemically mediated prezygotic barriers to reproduction likely play an important role in speciation. In facultatively sexual monogonont rotifers from the Brachionus plicatilis cryptic species complex, mate recognition of females by males is mediated by the Mate Recognition Protein (MRP, a globular glycoprotein on the surface of females, encoded by the mmr-b gene family. In this study, we sequenced mmr-b copies from 27 isolates representing 11 phylotypes of the B. plicatilis species complex, examined the mode of evolution and selection of mmr-b, and determined the relationship between mmr-b genetic distance and mate recognition among isolates. Results Isolates of the B. plicatilis species complex have 1–4 copies of mmr-b, each composed of 2–9 nearly identical tandem repeats. The repeats within a gene copy are generally more similar than are gene copies among phylotypes, suggesting concerted evolution. Compared to housekeeping genes from the same isolates, mmr-b has accumulated only half as many synonymous differences but twice as many non-synonymous differences. Most of the amino acid differences between repeats appear to occur on the outer face of the protein, and these often result in changes in predicted patterns of phosphorylation. However, we found no evidence of positive selection driving these differences. Isolates with the most divergent copies were unable to mate with other isolates and rarely self-crossed. Overall the degree of mate recognition was significantly correlated with the genetic distance of mmr-b. Conclusions Discrimination of compatible mates in the B. plicatilis species complex is determined by proteins encoded by closely related copies of a single gene, mmr-b. While concerted evolution of the tandem repeats in mmr-b may function to maintain identity, it can also lead to the rapid spread of a mutation through all copies in the genome and thus to reproductive isolation. The mmr-b gene is evolving

  14. Changing climate cues differentially alter zooplankton dormancy dynamics across latitudes.

    Science.gov (United States)

    Jones, Natalie T; Gilbert, Benjamin

    2016-03-01

    In seasonal climates, dormancy is a common strategy that structures biodiversity and is necessary for the persistence of many species. Climate change will likely alter dormancy dynamics in zooplankton, the basis of aquatic food webs, by altering two important hatching cues: mean temperatures during the ice-free season, and mean day length when lakes become ice free. Theory suggests that these changes could alter diversity, hatchling abundances and phenology within lakes, and that these responses may diverge across latitudes due to differences in optimal hatching cues and strategies. To examine the role of temperature and day length on hatching dynamics, we collected sediment from 25 lakes across a 1800 km latitudinal gradient and exposed sediment samples to a factorial combination of two photoperiods (12 and 16 h) and two temperatures (8 and 12 °C) representative of historical southern (short photoperiod, warm) and northern (long photoperiod, cool) lake conditions. We tested whether sensitivity to these hatching cues varies by latitudinal origin and differs among taxa. Higher temperatures advanced phenology for all taxa, and these advances were greatest for cladocerans followed by copepods and rotifers. Although phenology differed among taxa, the effect of temperature did not vary with latitude. The latitudinal origin of the egg bank influenced egg abundance and hatchling abundance and diversity, with these latter effects varying with taxa, temperature and photoperiod. Copepod hatchling abundances peaked at mid-latitudes in the high temperature and long photoperiod treatments, whereas hatchling abundances of other zooplankton were greatest at low latitudes and high temperature. The overall diversity of crustacean zooplankton (copepods and cladocerans) also reflected distinct responses of each taxa to our treatments, with the greatest diversity occurring at mid-latitudes (~56 °N) in the shorter photoperiod treatment. Our results demonstrate that hatching cues

  15. 池塘养殖匙吻鲟与鳙胃肠道饵料生物的比较%COMPARISON OF FOOD ORGANISMS IN GASTROINTESTINAL TRACT OF PADDLEFISH (POLYODON SPATHALA) AND BIGHEAD CARP (ARISTICHTHYS NOBILIS) FROM POND

    Institute of Scientific and Technical Information of China (English)

    李学梅; 朱永久; 杨德国; 何勇凤

    2013-01-01

    通过对同一试验池中匙吻鲟(Polyodon spathala)和鳙(Aristichthys nobilis)胃肠道内含物的连续3次分析,揭示他们滤食的天然饵料生物组成及差异。首先根据物种鉴定结果对2种鱼的胃肠道内饵料生物组成进行了UPGMA聚类分析,结果显示:相同采样时间同一池塘内2种鱼饵料生物组成存在差异,分别聚为不同的分枝;分析匙吻鲟和鳙胃肠道内饵料生物种类时还发现不同采样时间前者枝角类和桡足类种类数均多于后者。同时对2种鱼胃肠道内各饵料生物的生物量进行分析,结果显示:当大型饵料生物充足时,枝角类和桡足类的生物量在2种鱼胃肠道内没有显著差异(P>0.05);当大型饵料生物减少时,匙吻鲟摄食强度减小,但其枝角类和桡足类的生物量仍显著较大(P0.05);when cladocerans and copepods were lack in the pond, the feeding intensity of paddlefish declined, but the biomasses of cladocerans and copepods was still higher (P>0.05); however, when the cladocerans and copepods disappeared in the pond, the biomass of rotifer in paddlefish increased more (P<0.05); in contrast, smaller food organisms were filtered by bighead carp in the different periods. In addition, more bioflocs had been filtered by two fish species as the animal food organisms becoming fewer and fewer. In conclusion, there was feeding competition pressure between paddlefish and bighead carp in the same pond, which was closely related to the larger prey richness in the pond.

  16. Water quality and potamoplankton evaluation of the Nile River in Upper Egypt

    Directory of Open Access Journals (Sweden)

    Ahmed Mohamed El-Otify

    2015-06-01

    by the alternate dominance between diatoms and cyanobacteria, while zooplankton community was always dominated by rotifers. Phytoplankton populations were numerically more abundant in autumn and zooplankton peaked in spring.ConclusionsWastewater disposal restricted the abundance of the Nile zooplankton assemblages mainly due to the numerical decline of Rotifera and Cladocera. Otherwise, wastewater did not exert major limits for phytoplankton. The data obtained in this investigation will be crucial to understand potamoplankton regulation and contribute to the knowledge regarding the Limnology of the Nile basin.

  17. Examination of a smallest CELSS (microcosm) through an individual-based model simulation

    Science.gov (United States)

    Ishikawa, Y.; Yoshida, H.; Kinoshita, M.; Murakami, A.; Sugiura, K.

    2004-01-01

    Research of the effect of space environment on an ecosystem consisting of plants and animals is essential when they are to be positively used in space. Although there have been experiments on various organisms under space environment in the past, they mainly studied the effect of space environment on an individual organism or a single species. Microcosm is drawing attention as an experimental material of an ecosystem consisting of multiple species. The object in this research is to understand the nature of this network system called ecosystem. Thus, a mixed microorganism culturing system consisting of three types of microorganisms which form a minimum food chain system as a closed ecosystem (chlorella as the producer, bacteria as the decomposer, and rotifer as the consumer) was taken for the subject, on which to research the universal characteristics of ecosystems. From the results of experiments under the terrestrial environment, formation of colonies, which is an ecological structure, has been observed at its mature stage. The organisms form an optimal substance circulation system. Therefore, formation of colonies in simulation models is important. Many attempts have been made to create ecosystem models. For example, the Lotka-Volterra model forms a simultaneous equation with the differential equation expressing predator and prey relationship and many numerical calculations have been conducted on various ecosystems based on expanded L-V models. Conventionally, these top-down methods have been used. However, since this method only describes the average concentration of organisms that are distributed uniformly throughout the system and cannot express the spatial structure of the system, it was difficult to express ecosystem structures like colonies and density distributions. In actual ecosystems, there is heterogeneity in the number of individuals and in substance density, and this is thought to have great significance in ecosystems. Consequently, an individual

  18. Tree species traits influence soil physical, chemical, and biological properties in high elevation forests.

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    Edward Ayres

    Full Text Available BACKGROUND: Previous studies have shown that plants often have species-specific effects on soil properties. In high elevation forests in the Southern Rocky Mountains, North America, areas that are dominated by a single tree species are often adjacent to areas dominated by another tree species. Here, we assessed soil properties beneath adjacent stands of trembling aspen, lodgepole pine, and Engelmann spruce, which are dominant tree species in this region and are distributed widely in North America. We hypothesized that soil properties would differ among stands dominated by different tree species and expected that aspen stands would have higher soil temperatures due to their open structure, which, combined with higher quality litter, would result in increased soil respiration rates, nitrogen availability, and microbial biomass, and differences in soil faunal community composition. METHODOLOGY/PRINCIPAL FINDINGS: We assessed soil physical, chemical, and biological properties at four sites where stands of aspen, pine, and spruce occurred in close proximity to one-another in the San Juan Mountains, Colorado. Leaf litter quality differed among the tree species, with the highest nitrogen (N concentration and lowest lignin:N in aspen litter. Nitrogen concentration was similar in pine and spruce litter, but lignin:N was highest in pine litter. Soil temperature and moisture were highest in aspen stands, which, in combination with higher litter quality, probably contributed to faster soil respiration rates from stands of aspen. Soil carbon and N content, ammonium concentration, and microbial biomass did not differ among tree species, but nitrate concentration was highest in aspen soil and lowest in spruce soil. In addition, soil fungal, bacterial, and nematode community composition and rotifer, collembolan, and mesostigmatid mite abundance differed among the tree species, while the total abundance of nematodes, tardigrades, oribatid mites, and prostigmatid

  19. Plankton and Macrobiota Composition and Diversity of Three Tropical Freshwaters Rivers in Ogun and Ondo States, Southwest Nigeria

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    Taofikat Abosede ADESALU

    2016-06-01

    Full Text Available Three different rivers in Ogun and Ondo states were investigated for both micro and macro-biota of the water bodies. Several physical and chemical properties of these rivers were determined. The pH value of the studied water bodies was essentially neutral with salinity values between 0.02 - 4.0‰. Microalgae communities were represented by three divisions: Cyanophyta, Bacillariophyta and Chlorophyta at Oluwa and Ifara Rivers (Ondo state, while at Ibefun River (Ogun state, five divisions: Cyanophyta, Bacillariophyta, Chlorophyta, Euglenophyta and Pyrrhophyta were identified. Diatoms dominated these water bodies, with Navicula radiosa Kutz. at Ifara River, Fragilaria sp. in Oluwa River, while out of 90 algal taxa identified in Ibefun river, 64 were diatoms species belonging to 26 genera, with Melosira sp. and Synedra sp. recording the highest numbers of cell count. Dinoflagellates recorded only Peridinium sp. while Phacus orbicularis Hubner and Trachelomonas sp. dominated the euglenoids. For the zooplankton composition at Ibefun, rotifers (75.95% were represented by Brachionus sp., which recorded 62.03%, and Gastropus sp. with 13.92% of the total zooplankton, thus dominated the spectrum, while the copepod recorded 22.78% of the total organisms, with Copilia sp. and Euchirella sp. having 8.86% each. The macrobenthic invertebrates were represented by 3 taxa, belonging to 3 groups, with the dominant group Insecta accounted for 57% of the total individuals (7 individuals/m2, while Oligochaeta and Hirudinea accounted for 29% and 14% respectively of the total individuals at Oluwa and Ifara Rivers. At Ibefun River, the macrobenthic invertebrates were represented by 5 taxa, belonging to 3 groups, Bivalves, Oligochaeta and Insecta, with bivalves being the dominant group (51.7% of the total individuals, as 64 individuals/m2, while Oligochaeta and Insecta accounted for 26.6% and 21.9% respectively of the total individuals. The dominant taxon, Macoma cumana

  20. Desempenho larval do camarão-d'água-doce (Macrobrachium rosenbergii De Man, 1879 submetido a diferentes regimes alimentares Larval performance of the freshwater prawn (Macrobrachium rosenbergii De Man, 1879 submitted to different feeding systems

    Directory of Open Access Journals (Sweden)

    Luciana Almada Thomaz

    2004-12-01

    tested by using the daily observation of the larval substages and the first metamorphoses. The larvae were stocked in a density of approximately 100 larvas.l-1, in 16 tanks, with 33 liters capacity. The experiment was divided in four experimental units (blocks. Four feeding systems were tested in the hatchering in an open circuit, with four replicates for treatment. The feeding systems in which progressive substitutions of the nauplii of Artemia sp. (nas were accomplished, for the rotifer Brachionus plicatilis (rots, the following treatments were tested: 100% Brachionus plicatilis (30 rots/mL (T1; 100% Artemia (5 nas/mL (T2, 60% Artemia (3 nas / mL + 40% Brachionus plicatilis (12 rots/mL (T3 and 40% Artemia (2 nas/mL + 60% Brachionus plicatilis (18 rots/mL (T4, Humid ration was added to all treatments. The results of the change of the larval stage demonstrated that there was not significant difference among the treatments T2, T3 and T4. The treatment T1 (100% Brachionus plicatilis had total mortality in the 14th day of the experiment. The effect of the occurrence of the first metamorphoses for post-larvae, ocurred at 27th day in the treatments T2, T3 and T4. Consequently, the hatchering cycle to the metamorphosis of 90% for post-larvae (PL1, was the same in the respective treatments (35 days. Therefore, the use of the enriched rotifer and frozen in the feeding systems of the larvae allowed a satisfactory performance in terms of larval development of M. rosenbergii until the passage for the post-larvae stage.

  1. 对虾高位池循环水养殖水体浮游动物生态特征研究%Ecological Characteristics of Zooplankton in the Higher Place Pond of Shrimp Recirculating Aquaculture System

    Institute of Scientific and Technical Information of China (English)

    魏小岚; 李纯厚; 颉晓勇; 戴明; 廖秀丽; 胡维安; 肖雅元; 李朋

    2013-01-01

    different recirculating quantity and aquaculture pattern might influence on the ecological characteristic of zooplankton in the cultured waters. The zooplanktons were mainly belonged to four categories in the higher place ponds of shrimp recirculating aquaculture system. Four categories had 21 generas and 35 species in the shrimp recirculating aquaculture ponds, and there were 43 generas and 61 species in the shrimp control pond. Species of rotifer, protozoan, cladocera and copepoda were accounted for 34.4%, 31.1%, 19.7% and 14.8% respectively in the total ratio. Dominant species of zooplankton mainly included protozoa and rotifers in the recirculating aquaculture ponds, however, on the lately experimental phase, they mainly included large crustacean animal in the control aquaculture pond. Density of zooplankton were 131.52~497.17 ind *L~' and 122.09-373.15 ind-L-1 in the recirculating aquaculture ponds and control aquaculture pond respectively, and the biomass of zooplankton respectively were 1.19-3.87 mg-L"1 and 0.64-3.01 mg-L"' in the recirculating aquaculture ponds and control aquaculture pond respectively. Density and biomass of zooplankton of the recirculating aquaculture ponds were higher than that of the control aquaculture pond, and there was a significant difference (P<0.05). Shannon-wiener diversity index of zooplankton was 1.01~2.08 between fluctuation in the recirculating aquaculture ponds, but shannon-wiener diversity index of zooplankton was 0.76-1.56 between fluctuation in the control aquaculture pond.

  2. Feeding habits and growth characteristics of larval, juvenile, and young F1 of Epinephelus fuscoguttatus (♀) × E. lanceolatus (♂)%棕点石斑鱼(♀)×鞍带石斑鱼(♂)杂交F1仔、稚、幼鱼的摄食与生长特性分析

    Institute of Scientific and Technical Information of China (English)

    于欢欢; 李炎璐; 陈超; 孔祥迪; 张廷廷; 刘莉; 徐万土; 庞尊方; 李文升

    2015-01-01

    consisted of about 15 fish. All samples were used to test how much the fish ate. Other indexes were tested with other samples, the number of samples ranged from 10 to 100. After sampling, we observed morphological characteristics of the fish fry using a dissect-ing microscope, dissected the digestive tract under the dissecting microscope, and recorded amount of bait that had been consumed. The results showed that:(1) the larval grouper started feeding 3 days after hatching when the wa-ter temperature was approximately 29–30°C and the salinity was approximately 29–30. The fish fry’s first bait was the ss type rotifer, followed by the L type rotifer, brine shrimp, and compound feed. The 3-day-old larvae were very weak, with a feeding rate of 32% and repletion rate of 25%. The 5-day-old larvae were more dynamic than the 3-day-old larvae, with a feeding rate of 81.82%and repletion rate of 36.36%. The feeding rate was above 90%when the larvae were older than 7 days old, and the repletion rate was above 90%when the larvae were older than 9 days old. (2) With growth and development of fish fry, the average feeding amount changed. The larvae required 2 h 30 min to achieve satiation at 10 days old, and digestion took 1 h 45 min. The juveniles required 35 min to achieve satiation at 34 days old, and digestion took 3 h 20 min. Young fish required 30 min to achieve satiation and 10 h 25 min for digestion at 48 days old. (3) The correlations between net weight (W) and feeding amount (Y) was expressed as Y=0.2078W−3.3738; average length (L) and days after hatching (X) was expressed as L=2.3159e0.0595X;net weight and days after hatching was expressed as W=0.0748e0.2021X;average length (L) and net weight (W) was expressed as W=0.0045L3.3775;and mouth width (Y) and days after hatching (X) was expressed as Y=1.9687e0.0605X. In this paper, feeding habits and growth characteristics were observed to provide a theoreti-cal basis for large-scale breeding of F1 Epinephelus fuscoguttatus

  3. STUDIES ON THE FEEDING BEHAVIOR AND MORPHOLOGICAL DEVELOPMENTS OFEPINEPHELUS MOARA IN EARLY DEVELOPMENT STAGES%云纹石斑鱼(Epinephelus moara)早期发育阶段的摄食与生长特性

    Institute of Scientific and Technical Information of China (English)

    陆丽君; 陈超; 马爱军; 翟介明; 王新安; 李伟业

    2011-01-01

    采用随机取样实验生态学方法,对人工培育的云纹石斑鱼的仔、稚、幼鱼各发育阶段的形态特征及摄食变化状况进行了观察和描述。结果表明,云纹石斑鱼仔、稚鱼生长期间,分别以牡蛎幼体、轮虫、卤虫为饵料,幼鱼摄食配合饲料。形态学数据测量结果表明,云纹石斑鱼仔、稚、幼鱼的全长、体重和日龄三者之间存在相关关系。全长与日龄的关系式为L=2.8058e0.0287D;体重与日龄的关系式为W=0.0004e0.0825D;全长与体重的关系式为W=0.001e0.103L,相关系数分别为0.8954、0.9054、0.7982。云纹石斑鱼摄食状况测量结果表明,在人工投喂条件下,5日龄仔鱼的摄食率为90%,18日龄仔鱼饱食率为100%。实验结果还表明,在全天光照条件下,仔鱼16:00—18:00达摄食高峰;自然昼夜条件下,仔鱼14:00达摄食高峰;在全天黑暗条件下,仔鱼没有明显的摄食高峰。说明仔鱼摄食具有明显的昼夜节律,均表现为白天摄食为主。%We used ecological method of simple random sampling to observe morphological features, growth changes and feeding conditions during larval development of Epinephelus moara. The results showed that, under hatching conditions at dissolved oxygen (DO) 6.2mg/L, temperature 20℃, salinity 30, pH 7.9, light 100 lx, it took 45 hours to hatch the larvae. The yolk of four day-old larvae almost disappeared and these lava started consuming oyster larvae. The 8--13 day-old larvae ate both the oyster larvae and S-rotifer; the 14--22 day-old larvae consumed L-rotifer; the 23--66 day-old larvae and juvenile can be fed with brine shrimp. At about 67 days, the larvae metamorphosis completed and began to eat compound feed. The results of morphological data show that, total length, body weight and the age larval, juvenile and young E. moara showed significant correlations. The relationship between total length and age (in days) can be expressed as L = 2.8058e0.0287D

  4. Observing early development of Scatophagus argus%金钱鱼早期发育的观察

    Institute of Scientific and Technical Information of China (English)

    蔡泽平; 胡家玮; 王毅

    2014-01-01

    sea water with a temperature between 27℃ and 28.5℃, salinity of 26‰and pH value between 8.10 and 8.25.The total length of the newly hatched larvae was 1.60±0.04 mm, and reached 1.79±0.04 mm over the course of the next four hours with an elliptical yolk sac. In sea water between 28.0℃ and 29.0℃ and salinity of 22-26‰, the total length of larvae was 2.23±0.05 mm after 24 hours;meanwhile, their yolk sacs were being absorbed visibly. For larvae at five days of age, the total length reached 2.85±0.07 mm and their yolk sacs and oil balls were absorbed completely. The width of their mouth was between 0.17 to 0.18 mm. They were able to ingest larval rotifers, of which the grain size was between 0.10 to 0.12 mm. For larvae at nine days of age, the total length reached 3.25±0.04 mm, Their stomachs and intestines were filled with feed. Nutrient conversion for larval population had been finished entirely by then. For larvae at 15 days of age, the total length reached 3.72±0.03 mm. The larvae were highly active to prey on rotifers and larval copepods, of which the grain size was between 0.12 to 0.18 mm. Black brown pigments became denser at the tails of the juveniles at 32 day of age, and four brown strips appeared on each side of the juvenile’s body. The dorsal fins, anal fins and abdomen fins had finished development basically in the meantime. A pair of peculiar three leaf-shaped skeleton tuber appeared in the rear of the skull. The width of the juvenile’s mouth grew to 0.50 mm. They mainly fed on copepods and diatoms. This study provides basic biological information for the early development of Scatophagus argu and breeding.

  5. Cryo-life habitability on a polythermal glacier in Greenland

    Science.gov (United States)

    Lutz, S.; Anesio, A. M.; Benning, L. G.

    2012-12-01

    Modern surface glacial ice and snow are extreme environments at the edge of Earth's biosphere and potential sites of biosignatures in future planetary missions. The primary colonization of snow and ice is an important biogeological scenario with clear implications for the life detection on other icy planets [1]. Hence, knowledge of the adaptations and survival strategies adopted by extremophiles - cryophiles - in terrestrial cryogenic environments is vital for our ability to process data from future planetary missions. Despite it being one of the most extreme habitats on Earth, glacial ice and snow fields are colonised by a plethora of organisms including snow algae, bacteria, fungi, protozoa, rotifers and even invertebrates [2]. Although low in number and diversity compared to other habitats, snow and ice algae are a major primary producer in glacial settings [3,4]. Their life cycle influences the structure and diversity of neighbouring microbial communities [5] and they produce a suite of complex molecules to protect themselves against cold [6], UV [7], or nutrient deficiency [8]. However, these adaptations are poorly understood and we know very little about the complexity of the biological inventory contained within snow and ice environments. We have been investigating the potential of carbon fluxes from snow to ice, cryoconites and runoff water on the polythermal Mittivakkat glacier in SE Greenland and the effect of cell retention at the glacial surface on the albedo. The complementary microbiological and geochemical characteristics have been characterized at a suite of sampling sites in the ablation, superimposed and accumulation zone of the glacier. Results from photosynthesis and respiration measurements (e.g., snow fields, cryoconites, glacial outflow, clean snow) show that snow and ice surfaces have the potential to accumulate algal cells which become an important source of organic carbon for cryoconites. The accumulation of cells at the glacial surface

  6. Vertical distribution of zooplankton in the water column of Lago Amapá, Rio Branco, Acre, Brazil

    Directory of Open Access Journals (Sweden)

    Erlei Cassiano Keppeler

    2004-06-01

    Full Text Available The aim of investigation was to study the model of vertical distribution in Lago Amapá, taking into consideration the seasonality of its zooplanktonic composition. Lago Amapá (10º2'36"S and 67º50'24"W is located in the floodplain of the Rio Acre. Samplings were conducted at three different depths of the water column, to study the vertical distribution of zooplankton populations and determine some physico-chemical and biological parameters of Lago Amapá. Weekly samples were taken with a Van Dorn sampler. The species showed greater concentrations at the by means of water column. Thirty-eight zooplankton species were found in the samples represented by Rotifera (30, Cladocera (5 and Cyclopoida (3. The temperature of the water column showed a tendency toward relatively high values (about 30ºC with little variation, consequently resulting in low viscosity. Based of Jaccard's index, it was seen that during the low-water phase, S1 and S3 of the three sampling stations studied, had greater similarity (Cj = 0.7058 in the middle of the water column. Lago Amapá showed characteristics in line with the intermediate disturbance hypothesis model, favoring colonization by opportunistic species such as rotifers.O objetivo desta investigação foi observar a distribuição vertical da comunidade do zooplâncton no Lago Amapá (10º2'36"S e 67º50'24"W, localizado na planície de inundação do Rio Acre. Amostragens foram conduzidas em três diferentes profundidades da coluna da água, considerando aspectos sazonais do zooplâncton, parâmetros físicos, químicos e biológicos. Coletas foram realizadas semanalmente com Garrafa de Van Dorn. As espécies apresentaram maiores concentrações no meio da coluna da água. Foram encontradas 38 espécies, assim distribuídas: Rotifera (30, Cladocera (5 e Cyclopoida (3. A temperatura da coluna da água em geral apresentou-se alta, em torno de 30ºC, com pequena variação, resultando em baixa viscosidade. O

  7. 博斯腾湖浮游动物群落结构特征与分布的季节性变化%Zooplankton in Bosten Lake:community characteristics and seasonal changes in distribution

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      于2010年6月至2011年1月对博斯腾湖大湖区浮游动物群落进行了4次调查研究。结果表明,共鉴出浮游动物83种(属),其中原生动物27种(属),轮虫42种(属),枝角类10种(属),桡足类4种(属)。浮游动物在种类上以淡水习见的广温性种类为主,兼有嗜暖种和嗜冷种;数量上小型浮游动物占优势(>64.8%);生物量上大型浮游动物(主要是枝角类)占主导地位(>85.2%)。物种丰富度指数8月(夏季)最高(1.52),1月(冬季)最低(0.74);物种多样性指数和物种均匀度指数10月(秋季)最高(3.01和0.95),1月最低(0.75和0.63)。群落多变量分析表明,博斯腾湖西北部(黄水区)和西南部浮游动物群落结构差异较大,从春季到秋季这种差异逐渐增大,冬季差异最小。本研究通过分析博斯腾湖浮游动物群落结构的种类组成、现存量、多样性指数和群落多变量探讨该湖浮游动物群落特征及其分布的季节性变化规律,以期为博斯腾湖水环境评价与保护、渔业资源合理利用和可持续发展提供理论依据。%We evaluated the community characteristics and distribution of zooplankton from June 2010 to January 2011 in Bosten Lake. We identified 83 species of zooplankton, including 27 species of protozoa, 42 species of rotifer, 10 species of cladocera, and 4 species of copepoda. The zooplankton assemblage consisted primarily of hackneyed eurythermal species with a few thermophil andcryophil species. Micro-zooplankton were the most ab-undant type (>64.8%), whereas macro-zooplankton (chiefly cladocera) dominated the total biomass (>85.2%). The species richness index was highest in summer (1.52) and lowest in winter (0.74). The species diversity index and species evenness index peaked in autumn (3.01 and 0.95, respectively) and were lowest in winter (0.75 and 0.63, respectively). Multi-variate analysis revealed that there were comparatively large differences in zooplankton community

  8. Indicadores de condición larvaria aplicados al camarón de río del norte Cryphiops caementarius (Molina, 1782, en condiciones de cultivo controlado Larval condition indicators applied to the northern river shrimp Cryphiops caementarius (Molina, 1782, under condition of controlled cultivation

    Directory of Open Access Journals (Sweden)

    María C Morales

    2012-09-01

    quality of the species, under conditions of culture. The larvae, were cultured, in a tank of 250 L with water at 20 psu, at a constant temperature (25° ± 1°C, controlled with a thermostat and with 100% refill every day. The diet consisted of microalgae (Nannochloris sp. and Isochrysis sp., rotifers (Brachionus plicatilis, nauplii of Artemia franciscana and formulated food. Five indicators were used, considering morphologic and behavior aspects: intestinal fill, midgut gland condition, gill development, swimming behavior and phototactic response. The indicators selected in the present work, were feasible of being used for the determination of the condition and quality of the larvae of C. caementarius, being able to make an effective follow-up and association with every condition of larval development, standardize desirable characteristics in the larvae and demonstrate verifiable results, using a protocol for culture and food supply. Moreover, it was possible to identify an extensive range of potential studies, based on the relationships that the morphology and the larval behavior support with the physiological capacities of the larvae in development.

  9. Reaction of fresh water zooplankton community to chronic radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Osipov, D.; Pryakhin, E. [Urals Research Center for Radiation Medicine - URCRM (Russian Federation); Ivanov, I. [FSUE Mayak PA (Russian Federation)

    2014-07-01

    The characteristic features of ecological community as a whole and cenosis of zooplankton organisms as part of it determine the intensity of the processes of self-purification of water and the formation of a particular body of water. Identifying features of the structure and composition of the zooplankton community of aquatic ecosystems exposed to different levels of radiation exposure, it is necessary to identify patterns of changes in zooplankton and hydro-biocenosis as a whole. Industrial reservoirs, the storage of liquid low-level radioactive waste 'Mayak' for decades, have high radiation load. A large range of levels of radioactive contamination (total volume beta-activity in water varies from 2.2x10{sup 3} to 2.3x10{sup 7} Bq/l, total volume alpha-activity - from 2.6x10{sup -1} to 3.1x10{sup 3} Bq/l) provides a unique opportunity to study ecosystems in a number of reservoirs with increasing impact of radiation factor. We studied five reservoirs that were used as the storage of low-and intermediate-level liquid radioactive waste pond and one comparison water body. In parallel with zooplankton sampling water samples were collected for hydro-chemical analysis. 41 indicators were analysed in order to assess the water chemistry. To determine the content of radionuclides in the various components of the ecosystem samples were collected from water, bottom sediments and plankton. Sampling of zooplankton for the quantitative analysis was performed using the method of weighted average auto bathometer. Apshteyn's plankton net of the surface horizon was used for qualitative analysis of the species composition of zooplankton. Software package ERICA Assessment Tool 2012 was used for the calculation of the absorbed dose rate. Species diversity and biomass of zooplankton, the share of rotifers in the number of species, abundance and biomass decrease with the increase of the absorbed dose rate and salinity. The number of species in a sample decreases with the

  10. Factors that influence intestinal microflora formation in larval turbot (Scophthalmus maximus L.)%大菱鲆仔稚鱼发育早期肠道菌群结构形成的影响因素

    Institute of Scientific and Technical Information of China (English)

    史秀清; 王印庚; 张正; 廖梅杰; 李彬; 张述智; 李华

    2015-01-01

    为研究鱼类发育早期肠道菌群结构的演变过程及影响因素,运用高通量测序技术,分析了处于不同发育阶段的大菱鲆(Scophthalmus maximus)仔稚鱼肠道、受精卵、不同类型的饵料和水源中的菌群结构,以及它们之间的相关性。结果显示,以不同的OTU (Operational Taxonomic Units,可操作分类单元)作为分类依据,发现大菱鲆仔稚鱼的肠道菌群结构在开口摄食后不久已趋于稳定,其优势菌与受精卵所携带的细菌关联较大。并且在大菱鲆仔稚鱼不同的发育时期,这一菌群的结构非常稳固,几乎不受水和饵料中优势细菌的影响而发生改变。乳球菌属的Lactococcus piscium菌株一直是大菱鲆仔稚鱼肠道中的优势菌种,在不同发育时期的优势度高达45%~65%。本研究还发现,大菱鲆仔稚鱼肠道可能对定植的菌种具有选择性,一些水环境和饵料中的非优势菌,如 Streptococcus sp., Pseudomonas sp., Carnobacterium sp.等细菌也会定植于肠道,成为大菱鲆肠道中的次优势菌。%Turbot (Scophthalmus maximus) is a cold-water marine fish. In recent years, with the expansion and im-provement of turbot farming, bacterial disease has severely affected turbot development, especially in larvae. Because the fish have the special requirements for the living environment, disease occurrence is the result of interactions among fish, pathogens, and the environment. The gastrointestinal flora plays an important role in fish growth and development, and is closely related to disease occurrence. Therefore, it is necessary to investigate the gastrointestinal flora of larval fish. In this study, factors that influence gastrointestinal microflora formation and succession in turbot larvae were in-vestigated by high-throughput sequencing. The intestinal tract microflara and their relationships with different devel-opment stages (e.g., larvae and fertilized eggs), chlorella, rotifer, artemia, pellet feed, and

  11. Microcrustáceos y Vibrio cholerae O1 viable no cultivable (VNC: resultados en la Cuenca del Río Salí, Tucumán, Argentina Microcrustaceans and viable but nonculturable (VNC Vibrio cholerae O1: results in the Salí River basin, Tucumán, Argentina

    Directory of Open Access Journals (Sweden)

    Cecilia Locascio de Mitrovich

    2010-01-01

    cholera in the Salí River Basin (Tucumán Argentina, samples were taken during the years 2003 to 2005, taking into consideration physic -chemical, biological and sanitary aspects. To infer about the probable reservoirs of the pathogen, we examined the zooplankton of the Salí River (“Canal Norte” and “Banda Río Salí” and Lules River. The highest taxonomic representation was recorded for copepods, especially Eucyclops neumani (Pesta, 1927, along with Acanthocyclops robustus (Sars, 1863, Metacyclops sp., Paracyclops chiltoni and Notodiaptomus incompositus (Brian, 1925, plus some rotifers and cladocerans such as Lecane sp. and Brachionus sp., Moina sp. and Leydigia sp. The occurrence frequency was low, not exceeding 25%. Canal Norte stood out as the best environment for the species richness, abundance and constancy of the community. The physicochemical variables associated with the zooplankton would coincide with the values that, for our records and previous reports, are known for the development of the pathogen. In summer periods there was coincidence between the presence of the VNC form of V. cholerae O1 (immunofluorescence with antibodies anti O1 and the development of zooplankton. VNC forms on ciclopoid copepods and chidorids cladocerans appendages or structures were observed, probably showing an affinity with chitin substrates.

  12. Variación estacional e influencia de la turbidez y la salinidad sobre el zooplancton de un lago salino de la región central de Argentina Seasonal variation and influence of turbidity and salinity on the zooplankton of a saline lake in central Argentina

    Directory of Open Access Journals (Sweden)

    Santiago Andrés Echaniz

    2011-07-01

    Full Text Available The limnology of saline water bodies at other latitudes is fairly well known, but in Argentina such studies have only recently begun. The applicability of many conclusions regarding the functioning of these environments around the world is limited due to the scant ecological knowledge of some endemic species recorded in the assemblages of Argentine lakes. The aims of this work were to determine the effects of salinity and inorganic turbidity on the taxonomic composition, abundance, and zooplankton biomass in a shallow, hypereutrophic, mesosaline lake in the north of La Pampa province characterized by seasonality, variations in level and salinity, and the lack of macrophytes and fishes, and to compare it with other shallow lakes of the province. We found important differences with other saline lakes: the species richness was lower; the mean abundance of zooplankton was between four and six times higher; and rotifers, which were not affected by salinity or the concentration of inorganic suspended solids, were numerically predominant. Crustaceans, on the other hand, were negatively affected by these environmental factors. Biomass was twofold higher than that recorded in the same period in two shallow lakes of Pampa, with similar nutrient concentrations but lower salinities.La limnología de los cuerpos de agua salinos de otras latitudes es bastante conocida, pero en Argentina se ha comenzado a estudiar recientemente. Muchas conclusiones sobre el funcionamiento de estos ambientes a nivel mundial son de aplicación restringida debido a que las asociaciones registradas en los lagos argentinos tienen algunas especies endémicas, cuyo conocimiento ecológico es escaso. Los objetivos de este trabajo fueron determinar los efectos de la salinidad y la turbidez inorgánica sobre la composición taxonómica, abundancia y biomasa zooplanctónica en un lago somero mesosalino hipereutrófico del norte de La Pampa, caracterizado por su temporalidad, variaciones

  13. Fatty acid composition analysis and their nutrient effect evaluation of some pelagic food organisms%几种饵料浮游动物脂肪酸组成分析及营养效果评价

    Institute of Scientific and Technical Information of China (English)

    林元烧; 曹文清; 郑爱榕; 李文权; 陈清花

    2001-01-01

    本文采用气相色谱分析法对海水鱼类育苗常用的4种饵料浮游动物的脂肪酸组成和含量进行了测定分析.结果表明:卤虫无节幼虫、皱褶臂尾轮虫、蒙古裸腹溞和太平洋纺锤水蚤的粗脂肪含量分别占其体重的21.54%、9.70%、6.67%和4.66%.单不饱和脂肪酸的含量排序分别为蒙古裸腹溞>纺锤水蚤>轮虫>卤虫;多不饱和脂肪酸含量则为卤虫>裸腹溞>轮虫>纺锤水蚤.此外,太平洋纺锤水蚤尚含有C22:6(DHA)高不饱和脂肪酸,这在其它饵料生物中并未检出.卤虫无节幼虫和褶皱臂尾轮虫的脂肪酸组成中,油酸(C18:1)、亚油酸(C18:2)和亚麻酸(C18:3)占有较大比例,而二十碳以上的不饱和脂肪酸含量很低.文中讨论了脂肪酸组成和含量与营养效果的关系.%Fatty acid composition and contents in 4 kinds of planktonic food animals were measured quantitatively by means of gas chromatographic technique. The coarse fat occupied their body weight (wet weight) in nauplii of Artemia salina (cysts from Great Salt Lake, USA),Brachionus plicatilis (Rotifer), Moina mongonica (Cladocera) and Acartia paci fica (Copepod)were 21.54, 9.7, 6.67 and 4.66%, respectively. The total mono-unsatisfied fatty acid (TMUFA) ranks in descent sequence of M. mongonica, A. pacifica , B. plicatilis, Ar. salina, and total poly-unsatified fatty acid (TPUFA) Ar. salina, M. mongonica, B. plicatilis and A.pacifica. DHA (C22:6) was detected only in A. pacifica samples. There were greater propotion of C18: 1, C18:2 and C18:3 in Ar. salina and B. plicatilis samples comparative to A. pacifica and M. mongonica, but the contents of unsatisfied fatty acid which carbon number is more than 20 were scarce. The relationship between contents of fatty acid and nutrient effect on the health and survivorship of marine fry culture was discussed in this paper.

  14. Soil Communities of Central Park, New York City: A Biodiversity Melting Pot

    Science.gov (United States)

    Ramirez, K. S.; Leff, J. W.; Wall, D. H.; Fierer, N.

    2013-12-01

    high: >540,000 bacterial and archaeal species; and >97,000 eukaryotic species (as determined using a 97% sequence similarity cutoff). The most dominant bacterial phyla include Proteobacteria, Acidobacteria, Bacteroidetes, Verrucomicrobia and Actinobacteria, and Archaea represent 1-8% of the sequences. Additionally, the distribution patterns of Acidobacteria and consequently beta-diversity, was strongly related to soil pH. The most dominant eukaryotic taxa include many Protists (Rhizara, Gregarinia), Fungi (Basidiomycota, Ascomycota), and Metazoa (Nematodes, Rotifers, Arthropods and Annelids). No single soil factor could predict eukaryotic distribution. Central Park soil diversity was strikingly similar to the diversity of the 57 global soils. Central Park and the global soils had similarities in alpha diversity, taxon abundances. Interestingly, there was significant overlap in a number of dominant species between Central Park and the global soils. Together these results represent the most comprehensive analysis of soil biodiversity conducted to date. Our data suggest that even well-studied locations like Central Park harbor very high levels of unexplored biodiversity, and that Central Park biodiversity is comparable to soil biodiversity found globally.

  15. CHARACTERISTICS OF PLANKTON COMMUNITY STRUCTURE IN THE FISH CAGE CULTURE AREA OF YONGJIANG RIVER%南宁邕江网箱养殖区浮游生物种群结构特征

    Institute of Scientific and Technical Information of China (English)

    陈琴; 程光平; 李文红; 姬永杰; 桑明远; 左婷; 赵天龙

    2013-01-01

    Plankton is an important biological indicator for water quality assessment. In order to understand the water trophic status in the fish cage culture area of Yongjiang River, Nanning City of Guangxi Province, the population composition, quantity and dominant species of plankton were studied based on bimonthly sampling from September 2009 to September 2010. All data were collected from two sampling sites located between Jinling River and Qingchuan River, which was the main cage culture area in Yongjiang River. The results indicated that a total of 8 phyla and 98 species of phyto-plankton were identified. The species numbers of Chlorophyta and Bacilla riophyta represented for 42.8% and 24.5% of total species richness. Four phylums and 44 species of zooplankton were identified, in which rotifer dominates 43.2%. In general, more plankton species were found in summer and autumn than that in winter and spring. The seasonal variations of plankton density and species number were identical. The comprehensive trophic level index (TLI) values were between 59.28 and 66.87, which means that the water quality in the fish cage culture area of Yongjiang River was in between mesotrophic and nutritious level. The Shannon-Wiener diversity varied from 1.35 to 1.56, while evenness indices from 0.2275 to 0.2586, it means that the relevant water quality was in between mesotrophic and nutritious level. The studies show that the water trophic status evaluation results of the fish cage culture area along Yongjiang River detected by TLI was consistent with that of the Shannon-Wiener diversity index and evenness indices.%浮游生物是评价水体质量的一项重要生物指标,为了解广西南宁邕江网箱养殖区的水质状况,于2009年9月-2010年9月在金陵至清川桥江段网箱养殖区设置2个监测断面,每两个月采样1次,对其水质和浮游植物种群组成、密度和优势种变化进行了系统研究.结果表明:邕江网箱养殖区共检出浮游植物8

  16. UV Mutagenesis and Screening for Ammonium Tolerant Strains of Chlorella vulgaris%小球藻(Chlorellavulgaris)抗铵品系的紫外诱变选育

    Institute of Scientific and Technical Information of China (English)

    曹晓菲; 丰圣伟; 宋新伟; 徐涤

    2016-01-01

    【目的】获得耐受高铵浓度的优良养殖小球藻(Chlorellavulgaris )品系,可以有效防止其在养殖过程中被轮虫,纤毛虫等污染生物吞食。【方法】首先对小球藻进行紫外线诱变,然后用高浓度 NH4 HCO3作为筛选压力对其进行筛选。【结果】筛选到具有生长优势的小球藻突变株 B4和 C6,培养12 d,在 NH4 HCO3浓度为800 mg/L、1000 mg/L、1200 mg/L条件下,B4和C6的生物量比出发藻株分别提高41.18%和9.54%,32.64%和29.41%,37.74%和22.85%;对比出发藻株,B4和C6的最大光能转化效率有显著提高。【结论】突变株 B4和C6在高铵培养条件下更能显示生长优势,且它们的生长优势可能来自光合效率的提高。%Objective]Breeding the new strains of Chlorella vulgaris that have a tolerance to high concentration of ammonium can efficiently avoid being eaten by the contamination animals such as rotifer,ciliate and so on during cultivation.[Methods]The original strain of Chlorella vulgaris was first mutated by exposing to UV light and then was screened by the high concen-tration of ammonium in media.[Results]Two mutants,B4 and C6,were acquired with better growth rate than the original one.The biomass of strains B4 and C6 after being cultivated for 12 d increased 41.18% and 9.54%,32.64% and 29.41%,37.74% and 22.85%,respectively, under different ammonium concentration,which was 800 mg/L,1 000 mg/L,and 1 200 mg/L. The Fv/Fm results also proved a significant improvement on their maximum light conversion efficiency.[Conclusion]The mutants B4 and C6 showed growing advantages under higher am-monium concentration,which may be gained from the enhancement of photosynthesis efficien-cy.

  17. Lake Granbury and Lake Whitney Assessment Initiative Final Scientific/Technical Report Summary

    Energy Technology Data Exchange (ETDEWEB)

    Harris, B. L. [Texas AgriLife Research, College Station, TX (United States); Roelke, Daniel [Texas AgriLife Research, College Station, TX (United States); Brooks, Bryan [Texas AgriLife Research, College Station, TX (United States); Grover, James [Texas AgriLife Research, College Station, TX (United States)

    2010-10-11

    blooms. Our numerical modeling results support the idea that cyanobacteria, through allelopathy, control the timing of golden algae blooms in Lake Granbury. The in-lake experiments in Lake Whitney and Lake Waco also revealed that as golden algae blooms develop, there are natural enemies (a species of rotifer, and a virus) that help slow the population growth. Again, better characterization of these organisms is a high priority as it may be key to managing golden algae blooms. Our laboratory and in-lake experiments and field monitoring have shown that nutrient additions will remove toxicity and prevent golden algae from blooming. In fact, other algae displace the golden algae after nutrient additions. Additions of ammonia are particularly effective, even at low doses (much lower than what is employed in fish hatchery ponds). Application of ammonia in limited areas of lakes, such as in coves, should be explored as a management option. The laboratory experiments and field monitoring also show that the potency of toxins produced by P. parvum is greatly reduced when water pH is lower, closer to neutral levels. Application of mild acid to limited areas of lakes (but not to a level where acidic conditions are created), such as in coves, should be explored as a management option. Finally, our field monitoring and mathematical modeling revealed that flushing/dilution at high enough levels could prevent P. parvum from forming blooms and/or terminate existing blooms. This technique could work using deeper waters within a lake to flush the surface waters of limited areas of the same lakes, such as in coves and should be explored as a management option. In this way, water releases from upstream reservoirs would not be necessary and there would be no addition of nutrients in the lake.

  18. 环境污染对几类水生无脊椎动物内分泌功能扰乱的研究现状%Current status of environmental endocrine disruption in selected aquatic invertebrates

    Institute of Scientific and Technical Information of China (English)

    Enmin ZOU

    2003-01-01

    近年来,在环境毒理学这门边缘学科中又诞生了一个新的领域,即环境污染对内分泌功能的扰乱.研究发现,许多人工合成的杀虫剂和工业化合物能够扰乱脊椎动物的内分泌功能,这些化合物也存在于水环境中.近年来,这些环境有机污染物是否对水生无脊椎动物的内分泌功能同样具有扰乱作用成了环境内分泌学这个新领域的热点之一.由于近年来的研究侧重于腔肠动物、轮虫、软体动物、甲壳动物及棘皮动物,因此,本文主要介绍有关环境污染物对这几类水生无脊椎动物内分泌功能扰乱的研究进展.另外,对环境污染对水生无脊椎动物内分泌扰乱这个研究热点的现状以及今后的发展方向进行了评述.在从事环境污染对无脊椎动物内分泌功能影响的研究时,研究者必须意识到无脊椎动物和脊椎动物在内分泌机制上的差异,不可随意地在这两大类动物类群之间互相引伸研究结果.%Endocrine disruption by environmental contaminants has recently emerged as a new subdiscipline of environmental toxicology. Aquatic environments are increasingly contaminated with various anthropogenic chemicals,many of which are capable of disrupting endocrine functions of vertebrates. Where aquatic invertebrates are concerned, most of the recent reports are concerned with the impact of organic xenobiotics on endocrine functions in cnidarians, rotifers, mollusks, crustaceans and echinoderms. This review provides an overview of the current status of this research on endocrine disruption in these invertebrates. Suggestions for future research directions in the field of invertebrate endocrine disruption are also presented. Because of the disparities between the endocrine systems of invertebrates and vertebrates, care must be exercised in extrapolating to invertebrates, particularly the non-deuterostome invertebrates, the results of endocrine disruption studies with vertebrates

  19. The diet of Scinax angrensis (Lutz tadpoles in an area of the Atlantic Forest (Mangaratiba, Rio de Janeiro (Amphibia, Anura, Hylidae Dieta de girinos de Scinax angrensis (Lutz na Floresta Atlântica (Mangaratiba, Rio deJaneiro (Amphibia, Anura, Hylidae

    Directory of Open Access Journals (Sweden)

    Izidro F. de Sousa Filho

    2007-12-01

    Full Text Available Scinax angrensis (Lutz, 1973 is an endemic species, which occurs in low altitude hillside forests, distributed from the municipalities of Mangaratiba to Parati in the south of the state of Rio de Janeiro, Brazil. The aim of this study was to compare the morphology of S. angrensis tadpoles in two different stages of development, and verify their feeding spectrum. The mouth morphology of the two stages studied (27 and 37 appeared similar, with a difference in the size of the oral opening as well as an increase in the dimensions of the body. The examined species presented a trophic spectrum comprised of algae, protozoan, rotifers, microcrustaceans, nematodes, vegetation and invertebrate remains, fungus hyphae, and sand grains. Significant differences were found between dimensions of the two stages, but not between diets, although a differentiated preference with regards to planktonic items has been verified. The results suggest that the partitioning of feeding resources is not only related to morphology and occupation of different microhabitats but also to the feeding behaviour of tadpoles. The relevance of important food items to the natural diet of S. angrensis tadpoles, especially the diatoms and filamentous algae, reveal the importance of the periphytic community to the conservation of this species in the Atlantic Forest.Scinax angrensis (Lutz, 1973 é uma espécie endêmica ocorrendo em florestas de encosta de baixa altitude, no sul do Estado do Rio de Janeiro, Brasil. O objetivo do presente estudo foi o de comparar a morfologia e verificar o espectro alimentar de girinos de S. angrensis de dois estágios diferenciados de desenvolvimento. A morfologia bucal dos dois estágios (27 e 37 apresentou-se similar, havendo diferença de tamanho da abertura oral, bem como aumento das dimensões do corpo e da cauda. A espécie examinada apresentou um espectro trófico integrado por algas, protozoários, rotíferos, microcrustáceos, nematódeos, restos

  20. Análisis de los componentes zoobentónicos en un bordo temporal utilizado para acuicultura extensiva en Norte del Estado de Guerrero, México.

    Directory of Open Access Journals (Sweden)

    Quiroz-Castelán, Héctor

    2009-04-01

    of a body of water and the degree of contamination by the presence of certain groups and is a key source of food for fish farming in semi-intensive or extensive systems, the objective of this study were: Analyzing the main components of zoobenthos abundance, distribution and its relation to biotic and abiotic factors in a temporary earth pond that is located north of the town of Piedras Negras, Guerrero, Mexico. Collections of samples of zoobenthos, phytoplankton and monitoring of physical and chemical parameters were conducted every 30 days at four sites. The groups of organisms reported in the benthic coastline region were 12:Chironomids (Class insecta were the dominant group (20.75%, followed by copepods (16.11%, ostracods (11.21%, cladocerans (10.18%, oligochaetes ( Class annelid worms (9.41%, gastropods (8.89%, nematodes and rotifers (7.99%, Tardigrada (3.87%, insects (2.84%, hydracarina (0.52% and Hirudinea (class annelid worms (0.26%. Presented significant variations in the physical-chemical parameters during different months of sampling, due to seasonality. There were significant correlations with some abiotic parameters. The abundance,distribution and composition of zoobenthonics organisms in temporaryearth pond "Laguna Seca," are related to the timing (phases ofconcentration and dilution.

  1. 福建省九龙江江东库区浮游动物的生态研究%The Ecological Research of Zooplankton in Jiangdong Reservoir of Jiulong River in Fujian Province

    Institute of Scientific and Technical Information of China (English)

    干建彗; 郭东晖

    2012-01-01

    The zooplankton community of Jiangdong Reservoir was investigated in Jiulong River,Fujian province from March 2010 to February 2011. The result indicated that ninety-nine species were identified,of which 20 species were Protozoa,29 species were Rotif-era,39 species were Cladocera.and 11 species were Copepoda. The annual average abundance of zooplankton was 5 486. 73 L-1 ,the a-bundance of zooplankton was mainly determined by Protozoa and Rotifera,of which Protozoa was 4 926. 90 L-1,Rotifera was 552. 91 L-1 ,Cladocera was 5. 13 L-1 ,and Copepoda was 1. 79 L-1. The highest zooplankton abundance appeared in November, while the lowest in March. Temperature was the main influence factor of zooplankton community,and the abundance of Rotifera and Copepoda showed a significant positive relationship with Chlorophyll a. Sand mining probably accelerated the development of Protozoa, decreased the Margalef index of zooplankton. The pressure of fish prey and short retention time were the main reasons for low abundance of Cladocera and Copepoda.%于2010年3月-2011年2月对福建省九龙江江东库区的浮游动物进行了生态调查研究.研究结果表明,调查期间共采集到浮游动物99种,其中原生动物20种,轮虫29种,枝角类39种,桡足类11种.浮游动物丰度年均为5 486.73L-1,浮游动物的丰度主要由原生动物和轮虫组成,其中原生动物丰度最高,为4 926.90 L-1,轮虫为552.91L-1,枝角类为5.13 L-1,桡足类丰度最低,年均为1.79 L-1.浮游动物丰度最高值出现在11月,最低值出现在3月.温度是影响浮游动物群落的主要影响因子,轮虫和桡足类丰度分别与叶绿素a(Chl a)浓度存在显著正相关性.挖沙船的频繁活动可能促进了原生动物的生长,降低了浮游动物群落丰富度.短滞留时间和鱼类的捕食压力是造成枝角类和桡足类丰度低下的主要原因.

  2. Observation of embryonic and larval development of blood parrot cichlid fish Cichlasoma synspilum × C. citrinellum%红头丽体鱼×红魔丽体鱼杂交子一代胚胎发育及仔鱼形态学观察

    Institute of Scientific and Technical Information of China (English)

    孙志景; 姜巨峰; 傅志茹; 吴会民; 刘肖莲; 夏苏东; 张振国; 郝爽; 冯守明

    2014-01-01

    对红头丽体鱼[Cichlasoma synspilum(♀)]×红魔丽体鱼[C. citrinellum(♂)]杂交子一代(F1)(俗称“血鹦鹉”)的胚胎及仔鱼形态发育进行观察,描述了各发育时期的发育时序和形态特征。平均受精率为(91.33±3.06)%,平均孵化率为(91.67±2.08)%;血鹦鹉的受精卵呈椭圆球形,黏性,有浅黄、白灰和红褐3种颜色,无油球,平均卵长径为(1.89±0.04)mm;发育过程可分为6个阶段:受精卵阶段、卵裂阶段、原肠期、神经胚期、器官形成期和孵出期,并进一步分为28个发育分期;在水温(30±0.5)℃下历时约52 h 36 min 完成孵化。初孵仔鱼全长(3.71±0.05)mm,卵黄长径为(1.74±0.09)mm,短径为(1.25±0.07)mm,于第3天开始摄食轮虫,孵出后第5天卵黄囊完全消失。第13天全长(11.86±1.02)mm,各鳍条基本形成,进入稚鱼期。%We observed the embryonic and larval development of hybrids between Cichlasoma synspilum( ♀)and C. citrinellum (♂). The average fertilization rate and hatching rate were(91. 33 ± 3. 06)% and(91. 67 ± 2. 08)% ,respectively. The oval-shaped and adhesive fertile egg had three colors such as light yellow,white-gray and red brown without oil globule. The average length of fer-tile egg was(1. 89 ± 0. 04)mm. The progress of embryonic development comprised six stages:zygote stage,cleavage stage,gastrula stage,neurula stage,organogenesis stage and hatching stage,each divided into 28 periods. At water temperature of(30 ± 0. 5)℃ , the hatching time was 52 h 36 min. The total length of newly hatched larvae was(3. 71 ± 0. 05)mm with yolk sac length of(1. 74 ± 0. 09)mm in long diameter and(1. 25 ± 0. 07)mm in short diameter. The larva started to ingest rotifers after 3 d,and the yolk sac was consumed completely 5 d later. On 13th day,the total length of the larvae was(11. 86 ± 1. 02)mm and most of fin rays appeared, indicating that the

  3. 条石鲷(Oplegnathus fasciatus)发育早期的脂肪酸组成变化研究*%THE STUDY OF FATTY ACID COMPONENTS IN EARLY DEVELOPMENTAL STAGE OF OPLEGNATHUS FASCIATUS

    Institute of Scientific and Technical Information of China (English)

    徐善良; 王亚军; 王丹丽; 严小军

    2013-01-01

      采用GC/MS法分析了条石鲷(Oplegnathus fasciatus)的未受精卵、胚胎、仔鱼、稚鱼及幼鱼各阶段的脂肪酸组成特点及含量变动,旨在研究条石鲷发育早期脂肪酸的组成和变化规律。共检测到28种脂肪酸,其中饱和脂肪酸(SFA)13种,单不饱和脂肪酸(MUFA)7种,多不饱和脂肪酸(PUFA)8种。结果表明:(1)鱼卵中主要脂肪酸依次为 C16:0、C22:6(n-3)(DHA)、C20:5(n-3)(EPA)和C18:1(n-9)(油酸);(2)胚胎及内源性营养阶段,主要利用C16:0、C18:0以及C18:1作为能量来源, EPA和 DHA 被优先保存下来;(3)摄食轮虫和桡足类 AA、EPA、DHA 含量显著提高,摄食卤虫则C18:1(n-9)、C18:2(n-6)及C18:3(n-3)含量迅速增加;(4)在稚鱼期必需脂肪酸AA、DHA含量不足,而EPA过高,可能引起细胞膜磷脂中DHA与EPA比例失衡,出现稚鱼“死亡高峰”。%In order to investigate the fatty acid composition and changes of Oplegnathus fasciatus in early development, the total lipid and fatty acids composition of O. fasciatus in different developmental stages (unfertilized eggs, embryos, larval, juvenile, young) were measured by means of GC/MS. The O. fasciatus was sampled from the Hengma mariculture base of Ningbo Marine and Fisheries Research Institute, Ningbo, Zhejiang Province in May 2009. As a result, Twenty-eight fatty acids were detected in O. fasciatus, including 13 saturated fatty acids (SFA), 7 single unsaturated fatty acids (MUFA) and 8 poly unsaturated fatty acids (PUFA). Found the following characteristics:(1) The major fatty acids in eggs followed by C16:0, C22:6 (n-3) (DHA), C20:5 (n-3) (EPA) and C18:1 (n-9) (oleic acid), and the content of C16:0 was topped in each stage; (2) C16:0, C18:0 (SFA) and C18:1 (MUFA) were main source of energy metabolism during embryos and internal nutrition, while the DHA and EPA were preferentially preserved; (3) Feeding rotifers and copepods can significantly im-prove the

  4. The Argentinean network for the assessment and monitoring of Pampean shallow-lakes (PAMPA2)

    Science.gov (United States)

    Zagarese, H. E.

    2012-12-01

    . Species composition within the microbial plankton community is remarkable stable. But some important features vary seasonally. Although the microbial plankton biomass is higher around the summer solstice (SS), its phosphorous content per unit biomass is higher around the winter solstice (WS), which results in an unanticipated bimodal pattern of phosphorous concentration, with maxima occurring around the spring and fall equinoxes. Many optical characteristics also vary seasonally and suggest that, as a whole, the microbial plankton community is more autotrophic around the WS, and more heterotrophic around the SS. Life table experiments, using dominant zooplankton grazers (rotifers), indicated that the microbial food quality is higher in winter than in summer. Incoming solar radiation and temperature account for much of the lake seasonal dynamics. Shallow-lakes, such Laguna Chascomús are well suited for long-term studies and the emplacement of automated sensors. Despite the high system complexity, many processes are remarkable repeatable and reproducible at mesocosm-scales. Long-term time series of lake and weather variables will provide a strong basement for understanding climate variability, such as the cyclic changes in precipitation, which greatly affects lake depth; and the seemingly stochastic cold weather periods, producing massive winter fish kill events.

  5. INFLUENCE OF FRESHWATER DISCHARGE ON ZOOPLANKT COMMUNITY DISTRIBUTION IN THE MUDFLAT WETLANDS OF THE HANGZHOU BAY%淡水排放对杭州湾湿地浮游动物群落分布的影响

    Institute of Scientific and Technical Information of China (English)

    李共国; 屠霄霞; 王佩儿; 王自磐; 廖何朝兴; 杨季芳

    2013-01-01

    In order to understand the spatiotemporal distribution of zooplankton species composition,abundance and biodiversity in the mudflat wetlands of Hangzhou Bay,40 samples were conducted at middle to high tide levels in five sampling stations (S1-S3 for discharge area,and S4-S5 for non-discharge area) in April (spring),July (summer),October (autumn),2010 and January (winter),2011.A total of 38 species of zooplankton (15 Rotifera,4 Cladocera,19 Copepoda) were found.The annual average density (88.89 ind./L) and biomass (0.41 mg/L) of zooplankton in the discharge area were much higher than those,i.e.,4.21 ind./L and 0.10 mg/L,respectively,in the non-discharge area.The dominant species of rotifers and copepods in the discharge area were Brachionus calyciflorus and Sinocalanus dorrii,respectively,and Calanus sinicus dominated copepods in the non-discharge area.Water nutrient concentrations,community density,and biomass of the zooplankton at middle tide level in stations S2-S3 were much higher than those at high tide level.The zooplankton community in the mudflat wetlands,the effects of the freshwater discharge,tidal creek spread,and tidal conditions determined the temporal pattern of the main zooplankton species,and the tidal creek spread and tidal conditions explained differences in composition and structure between the middle and the high tide level.%于2010年4月至2011年1月对杭州湾南岸滩涂湿地5个断面(S1-S3为排水区,S4-S5为非排水区)的高潮位和中潮位分别进行浮游动物群落结构的周年调查,共发现浮游动物38种(轮虫15种,枝角类4种,桡足类19种).排水区浮游动物年平均密度88.89 ind./L,生物量0.41 mg/L,非排水区平均密度仅4.21 ind./L,生物量0.10 mg/L.排水区轮虫和桡足类的第一优势种分别为萼花臂尾轮虫(Brachionus calyciflorus)和汤匙华哲水蚤(Sinocalanus dorrii),而非排水区第一优势种为中华哲水蚤(Calanus sinicus).S2-S3断面中潮位的水体营养盐浓度、

  6. 长江口南北支浮游动物群落生态学研究%Zooplankton community ecology in north and south branches at Yangtze River estuary

    Institute of Scientific and Technical Information of China (English)

    郑金秀; 胡菊香; 彭建华; 汪红军

    2011-01-01

    The special ecological environment at Yangtze River estuary makes zooplankton there different from other water in ecological characteristics such as species composition, density and time-space distribution etc. Two times' investigations were taken in spring (drought season) and autumn (raining season) from2005 to 2006 along the north and south branches.where three cross-section and 20 survey points were set. A total of 227 zooplankton species were identified, with 65 species of rotifers, 107species of protozoas, IS species of cladocerans and 40 species of copepods. The Keratella, Polyarthra trigla.Brachionns calyciflorus.Difflugia, Arcella,tintinnid,Calanus sinicus, Sinocalanus dorrii.Mesocyclops leuckarti and Bosmina ect were the dominant species.This paper compared the species composition and structure of two branches. The zooplankton species, quantity and biomass in south branch is higher than that in north branch. Zooplankton community similarity in two branches is very low. The different environmental caused much different zooplankton community structure. Correlationship of zooplankton community structure and environmental factors were analyzed, among which water temperature was the important factor that determined the time distribution of zooplankton with seasonal change. The salinity influenced the ecological types and space distribution of zooplankton community structure. As a whole, the north and south branches were controled by Yangtze river, so that the zooplankton species were mainly rever-type and the salt-type appeared more in section 3.%长江口特殊的生态环境使得浮游动物的种类组成、密度和时空分布等生态特征有别于其它水体.2005年秋季(丰水期)和2006年春季(枯水期)对长江口南北支浮游动物进行了2个航次的调查,沿南北支由西向东设立3个采样断面共20个采样点.共采集到浮游动物227种,其中轮虫65种,原生动物107种,枝角类15种,桡足类40种.优势种包括龟甲

  7. The use of multivariate analysis to link sediment contamination and toxicity data to establish sediment quality guidelines: an example in the Gulf of Cadiz (Spain); El uso del analisis multivariante en la union de datos de toxicidad y contaminacion para establecer guias de calidad de sedimento: Un ejemplo en la Bahia de Cadiz (Espana)

    Energy Technology Data Exchange (ETDEWEB)

    Del Valls, T. Angel; Forja, Jesus M [Departamento de Quimica Fisica, Facultad de Ciencias del Mar, Universidad de Cadiz, Cadiz, (Spain); Gomez-Parra, Abelardo [Instituto de Ciencias Marinas de Andalucia, CSIC, Puerto Real, Cadiz, (Spain)

    1998-03-01

    To evaluate marine sediment quality in the Gulf of Cadiz, chemical concentration and toxicity test endpoints from sediments were linked using multivariate analysis. Sediment samples were collected synoptically at seven stations in two littoral ecosystems of the Gulf of Cadiz (five in the Bay of Cadiz and two in the salt marsh of the Barbate River), and subjected to six separate, replicated sediment toxicity tests and comprehensive sediment chemistry analyses. The toxic effects of sediments were tested using three operational sediment phases: whole sediment, using the estuarine amphipod Microdeutopus gryllotalpa (10 d static: survival) and the estuarine clam Ruditapes philippinaru (48 h static: survival) and of the marine fish Sparus aurata (48 h static. Survival); and interstitial water, using populations of the estuarine rotifer Brachionus Plicatilis (7 d static: Population decline) and of the marine bacteria Photobacterium phosphoreum (Microtox ). To evaluate the levels of contamination, the concentrations in the sediments of organic carbon, 14 trace metals (Fe, Mn, Cu, Zn, Pb, Cd, Ag, Hg, As, Sn, V, Ni, Co and Cr) and the surfactant linear alkylbenzenesulphonate (LAS) were measured. The results of the toxicity tests were compared in a dose-response relationship between sites, demonstrating a general agreement between the toxicity values determined by all the tests, except in the case of interstitial water toxicity (principally due to toxic mixtures of trace metals). Data derived from sediment chemistry and bioassays were assembled by multivariate statistical techniques (PCA and factor analysis), showing that the two data types could be represented by only five factors corresponding to five overlapping chemical-biological effect relations. Positive prevalence of these factors in the cases studied was used to establish those ranges in chemical concentrations associated with adverse effects. The sediment quality guidelines, in terms of concentrations at or below

  8. Feeding behavior of Frontonia leucas (Ehrenberg (Protozoa, Ciliophora, Hymenostomatida under different environmental conditions in a lotic system Comportamento alimentar de Frontonia leucas (Ehrenberg (Protozoa, Ciliophora, Hymenostomatida sob diferentes condições ambientais em um sistema lótico

    Directory of Open Access Journals (Sweden)

    Roberto Júnio P. Dias

    2006-09-01

    Full Text Available The objective of this study was to record and describe the morphological changes and the ingestion mechanisms of Frontonia leucas (Ehrenberg, 1833 according to the food type and to relate the food ingested with the different environmental conditions in a lotic system, namely São Pedro stream, located in the municipality of Juiz de Fora, Minas Gerais, Brazil. We sampled three points on a monthly basis from August 2002 to June 2003, each of which receiving different levels of untreated sewage. We prepared culture media for the ciliate specimens containing filtered water from each point and the types of food observed inside F. leucas (cyanobacteria, diatoms, desmids and testate amoebas. We observed the ingestion mechanisms of F. leucas in vivo, under a phase contrast optical microscope, using instantaneous sampling and sequence sampling as behavior observation methods, noting the following parameters: dissolved oxygen concentration, pH, conductivity and water temperature. We noted the F. leucas ciliates ingesting diatoms and desmids at collection point 1 and filamentous cyanobacteria, testate amoebas (Arcella and Centropyxis and rotifers at points 2 and 3. The present work records for the first time the ingestion of testate amoebas of the genus Centropyxis by F. leucas. We noted five ingestion mechanisms by F. leucas while feeding on cyanobacteria and testate amoebas of the genus Centropyxis, three of these related to the ciliary action and two involving physical changes in the cytoplasm. For ingestion of diatoms, desmid (Closterium and Arcella, the mechanisms involving ciliary action alone were sufficient for ingestion, since these preys are smaller than the ciliate under study. The autecological data registered for F. leucas were 1.98-8.01 mg l-1 O2, pH 6.9-8.73, 58-390 µS/cm and 19.5-26.2ºC, confirming its ample ecological valence.O objetivo do presente trabalho foi registrar e descrever as alterações morfológicas e os mecanismos de ingest

  9. Efeitos de fertilização na biomassa e qualidade nutricional do zooplâncton utilizado para alimentação de alevinos na estação de hidrobiologia e piscicultura de Furnas, MG Fertilization effects on biomass and nutritional quality of zooplancton in feeding of fry in the Furnas (MG, Brazil hydrobiology and pisciculture station

    Directory of Open Access Journals (Sweden)

    Raquel Magalhães Santeiro

    2000-05-01

    âncton também sugerem que a qualidade, a dosagem e a freqüência dessa adubação devem ser amplamente revistas.This investigation aimed to evaluate the effects of organic matter (pig manure and nutrients on the structure of zooplankton in plankton tanks at Furnas hatchery station. Zooplankton is commonly used as food resource of Hoplias lacerdae fry. Total lipid levels, density and biomass of zooplankton were analyzed in two plankton tanks twice a week during 60 days. Water temperature, pH, dissolved oxygen and electric conductivity were also monitored daily. Chlorophyll-a, total phosphorus, ammonium and total kejdahl nitrogen (TKN were measured on a weekly basis. In the first thirty days, nutrient fertilization was performed every five days. In the last thirty days, there was no external input of nutrient or organic material. The interruption of external nutrient load caused a clear and conspicuous modification in most physical and chemical variables as well as in the zooplankton. There was an abrupt and conspicuous reduction in the conductivity, ammonium, TKN, total phosphorus and chlorophyll. On the other hand, dissolved oxygen and pH increased. Biomass of total zooplankton also showed a brief peak following the interruption of external nutrient flux. During this period, the cladocera Moina and the rotifer Brachionus calyciflorus became the dominant zooplanktons. At the end of the study, the ciclopods became once more the dominant organisms, although there was a higher proportion of immature stages. Levels of total lipids of zooplankton remained at lower levels (6-10% throughout the covered period, suggesting that zooplankton was eating food particles of lower nutritional quality. Nevertheless, the study demonstrates that nutrient input is essential for maintaining zooplankton at adequate levels. However, lower lipid levels also suggest that the quality, quantity and frequency of this nutrient input showed be thoroughly revised.

  10. 卵胎生许氏平鲉仔鱼与稚鱼发育形态学特征观察%Morphometrics Development of Ovoviviparous Sebastes Schlegeli Hilgendorf Larvae and Juvenile

    Institute of Scientific and Technical Information of China (English)

    蔺玉珍; 于道德; 温海深; 李吉方; 母伟杰; 刘群; 赵君丽; 任源远; 张亚晨

    2014-01-01

    In this paper it is reveals the post-embryonic organization development of Sebastes schlegeli Hilgendorf in detail,the result shows that:0dph fry,the total length (TL)is 3.8~4.7mm,the oil ball is big and clear;1dph fry (initial hatch fry),TL is 5.0 ~ 6.5 mm,the fry’s mouth has been open,and not feeding,melanin only distributes on the surface;2dph,the fry start feeding Rotifer,the maw has gas,and rainbow color element emerges;3dph fry,a bundle pigment appears on the rear brain case,and the tail radiation silk appears,the food consumption increases greatly;4dph,fry,yolk sac has been absorbed,spotted yellow pigment begins to differentiate at the back of head and the top of ab-dominal cavity;5dph,pectoral fin vertically spreads outward,jaw opens frequently.12dph,the fry is clustered and phototropic;20dph,the front part of the fish is black,the fish disperses evenly in water, feeding exuberant;25dph,TL is 6.55~8.42mm,black stripe mark begins to appear in front part of the fish;30dph,on the edge of the head eye,there is a horizontal belt,three dark brown horizontal stripes appear at the fish body side;40dph,TL is 15.50~35.55mm,the body shape is similar to the salted fish,there are 6~7 dark brown horizontal stripes at the body side;60dph,the body shape is consistent with the adult,body development goes into the j uvenile stage,and begins to live in the lower water.Based on the morphological observation of ovoviviparous Sebastes schlegeli Hilgendorf in early development,and the embryo,larvae and j uvenile developmental regularity and species specificity,not only can we enrich our understanding of the early life history of the fish,but also instruct the produc-tion and breeding of Sebastes schlegeli Hilgendorf in the future.%本文对许氏平鮋胚后发育组织进行了较为详细观察,研究结果表明:许氏平鲉0日龄(dph)仔鱼,即未产出仔鱼,体长3.8~4.7mm,油球大而明显;初孵仔鱼体长5.0~6.5mm,已经开口,尚未摄食,体表仅分布有

  11. Comparison of benthos and plankton for selected areas of concern and non-areas of concern in western Lake Michigan Rivers and Harbors in 2012

    Science.gov (United States)

    Eikenberry, Barbara C. Scudder; Bell, Amanda H.; Templar, Hayley A.; Burns, Daniel J.

    2016-07-25

    Milwaukee Estuary, benthos richness was lower in the Milwaukee River subsite spring and summer samples and in the Menomonee River subsite spring sample relative to the paired non-AOCs. Benthos diversity and IBIs at the Menomonee River subsite and IBIs at the Milwaukee River subsite and Sheboygan River were significantly lower than at all non-AOCs as a group across all seasons and therefore were rated as degraded. In addition, IBIs at the Lower Menominee River were significantly lower than those at the paired non-AOCs during all seasons and were therefore rated degraded. Benthos at both Fox River subsites and the Milwaukee River subsite were significantly different from their paired non-AOCs during all three seasons, based on a comparison of the relative abundances of taxa using multivariate testing. Metrics for plankton at AOCs were not significantly lower than those at the paired or group non-AOCs during all seasons; however, zooplankton richness in spring at the Sheboygan River and in fall at the Menomonee River subsite was rated as degraded in comparison to paired non-AOCs. Also, zooplankton richness in fall at the Fox River near Allouez subsite and in spring at the Milwaukee River subsite was rated degraded overall because values were lower than at all non-AOCs as a group and lower than at the paired non-AOCs. Zooplankton diversity in fall at the Fox River near Allouez subsite and the Lower Menominee River was rated degraded in comparison to paired non-AOC comparison sites. Zooplankton communities at the Fox River near Allouez subsite were significantly different from the paired non-AOCs when multivariate comparisons were made without rotifers other than A. priodonta. Overall, benthos and zooplankton BUIs remained at the AOCs in 2012 but no AOCs with a phytoplankton BUI were rated degraded in comparison to non-AOCs. The use of a multiple ecological measures, structural and functional, and multiple statistical analyses, biological metrics and multivariate statistics

  12. Early ontogenesis of the angelfish, Pterophyllum scalare Schultze, 1823 (Cichlidae

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    Agata Korzelecka-Orkisz

    2012-09-01

    Full Text Available This study describes the egg membrane structures of angelfish (Pterophyllum scalare, morpho-physiological changes during angelfish embryogenesis from activation to hatching under optimal conditions (28°C; pH 6.8, the developing larvae and fry, the effect of alkaline pH on the early developmental stages of the species, the relationship between food item size and fry survival. Egg membranes (thin, transparent, 1.67-2.18 µm thick are covered by a sticky substance. The amber-coloured angelfish eggs were oval in shape, with average diameters of 1.436 and 1.171 mm, i.e., a mean volume of 1.033 ± 0.095 mm³. The survival rate of embryos and larvae kept in water with an elevated, slightly alkaline pH was very low: as few as 2% of the embryos survived, while in the batch kept in optimal water conditions very few eggs died. The first larvae hatched after 1288 h of embryonic development. The newly hatched larvae measured on average 2.60 ± 0.093 mm and had large (0.64 ± 0.077 mm³ yolk sacs. They attached themselves to the substrate with a secretion of thin, viscous threads, which was released from glands situated on the top of the head. The glands vanished on day 5. The 1-day-old larvae showed the first pigment cells on the body and the eyes of the 2-day-olds were already fully pigmented. Between day 4 and 5 of larval life, the larvae began feeding on live food. The 23-day-old fry looked like a miniature versions of the adults. Mortality of the angelfish larvae during their first days after hatching was higher in those fed brine shrimp (Artemia salina nauplii than those fed protozoans and rotifers.En este trabajo se ha descrito la estructura de las túnicas ovulares del escalar o pez ángel (Pterophyllum scalare, las modificaciones morfo-fisiológicas que transcurren durante la embriogénesis del escalar desde el momento de activización para el desove en condiciones ambientales óptimas (28ºC y pH 6,8 y, se han caracterizado las larvas y los

  13. Biological Assessment of Water Quality and Production Estimation of Silver Carp and Bighead Carp in Taibo Lake%太泊湖水质生物学评价及鲢鳙鱼产力评估

    Institute of Scientific and Technical Information of China (English)

    张燕萍; 陈文静; 王海华; 陶志英; 章海鑫; 王昌来

    2015-01-01

    the silver carp and bighead carp in the Taibo Lake was also cal-culated based on the quantity of plankton.Monthly surveys were conducted at 7 sample sites in May,July,Septem-ber and November of 2013 in Taibo Lake.Plankton samples were collected using plankton &zooplankton nets and identified by optical microscopy.At the same time,water samples were collected to determine the temperature, pH,dissolved oxygen,transparency,water depth,CODMn ,total nitrogen.Seven phyla of phytoplankton,including 5 1 genera,were found in the lake,with the an average phytoplankton density and biomass of 1 593 ×104 ind/L and 20.166 mg/L.Chlorophyta,Cyanophyta,Bacillariophyta and Euglenophyta were the dominant populations,ac-counting,respectively,for 24.3%,8.9%,16.2% and 25.84% of the total phytoplankton.The ranges of Shan-non-Wiener diversity index and Pielou evenness index of phytoplankton were 0.5 1 -0.64 and 0.30 -0.38,re-spectively.Twenty-five species of zooplankton from four categories were identified with the average density of 1 771.85 ind./L and the average biomass of 2.508 mg/L.The amount of the Protozoa (5 species),Rotifer (13 species),Cladocera (5 species)and Copepoda (2 species)contributed respectively,0.1%,78.7%,15.9%and 35 .2% to the total amount of the zooplankton biomass.Shannon-Wiener diversity index and Pielou evenness index of zooplankton ranged from 0.36 -0.46 and 0.34 -0.41 ,respectively.The total alkalinity in the Taibo Lake ranged from 62.92-89.09 mg/L,and the content of the total nitrogen,total phosphorus and the ammonia ni-trogen all exceeded the thresholds of environmental quality Level Ⅱ standards.In conclusion,the water quality of the Taibo Lake is eutrophic according to the comprehensive evaluation of our investigation results.The productions of silver carp and bighead carp were 151.2 kg/hm2 and 56.4 kg/hm2,about 322 t and 120 t throughout the lake estimated based on the productivity of plankton.

  14. Embryonic and Early Larval Development of Schizothorax wangchiachii%短须裂腹鱼胚胎与仔鱼早期发育特性研究

    Institute of Scientific and Technical Information of China (English)

    左鹏翔; 尹翔; 胡思波; 李光华; 冷云; 张建斌; 缪祥军; 王志飞; 崔丽莉; 梁祥; 钟文武

    2015-01-01

    culture of yolk-sac lar-vae were conducted in an incubator at constant water temperature ( 14 ±1 )℃ and embryonic and larval develop-ment were observed using a Nikon stereoscopic anatomical lens and recorded with a Nikon DS -Fil high-definition camera.At least 30 zygotes were sampled once each hour during the first 48-hour zygote development phase and then sampled once every two hours after that .Twenty larvae were sampled each day .Results show that mature and fertilized eggs were demersal , weakly glutinous with abundant yolk .The average diameter of fertilized eggs was 2.36 mm and 3.68 mm after swelling.Cleavage began at 6 h 30 min after fertilization at (14 ±1)℃.Blastula, gastrula and mid-gastrula stages occurred , respectively , at 20 h 55 min, 60 h 28 min and 70 h 4 min after fertiliza-tion.The neurula stage occurred at 77 h 52 min and muscles were observed to shrink at 142 h after fertilization. Heart pulsation began at 177 h 46 min and the newly hatched larvae were released from the membrane at 254 h 40 min after fertilization.Cumulative temperature was up to 3 565.3℃· h during the development process .The average total length of newly hatched larvae was 8.7 mm.The pectoral fins, gills, mouth cavity, eye pigmentation, blood vessels and other organs developed gradually from day 2-9 after hatching .On day 10 after hatching , the lar-vae reached 15 .15 mm and initial swim bladder inflation began .Yolk-sac absorption was complete after day 10 and the larvae could swim horizontally and began to search for food ( rotifers were supplied ) .The development time se-quence and morphological characteristics of Schizothorax wangchiachii development from zygote to yolk-sac larvae presented here will lay a theoretical foundation for industrial breeding of S.wangchiachii.

  15. 日本鬼鲉胚胎发育及仔、稚鱼形态学观察%OBSERVATION OF EMBRYONIC AND LAVAL DEVELOPMENT OF DEVIL STINGER, INIMICUS JAPONICUS

    Institute of Scientific and Technical Information of China (English)

    史会来; 楼宝; 王奋芬; 杨会成; 毛国民; 詹炜; 徐冬冬

    2012-01-01

    Artificial rearing technique for Inimicus japonicus was conducted at Xishan experimental ground of Zhejiang Marine Fisheries Research Institute from May to June 2011. After obtaining fertilized eggs by artificial insemination, we observed the embryonic and larval development of devil stinger using microscope and described the development time and morphological characteristics of each development stage, which provide basic information for the artificial breeding and early development. The results showed that fertilized eggs had perfectly spherical shape and were transparent, and average egg diameter was (1.42±0.04) mm and without oil globule. Furthermore, the eggs showed buoyancy in seawater at salinity 31. Embryos were incubated in seawater (salinity 31) at (22±0.5)°C. The time-table of major embryonic development stages of devil stinger were as follows: blastodisc forming stage at 15min post fertilization (pf); 2-cell stage at 25min pf; multicellular stage at 4h and lOmin pf; bastula stage at 7h and 20min pf; gastrula stage at 13h and 20min pf; neurula stage at 25h 40min pf; organogenesis stage at 26h lOmin pf; tail bud stage at 38h lOmin pf; heart beat stage at 40h 30min pf; muscular contraction stage at 46h 20min pf; pro-hatching stage at 52h lOmin pf; hatching stage at 52h lOmin pf. Newly hatched larvae usually lied on the water surface and had 3.0 mm in average in total length (TH) with yolk sac length of 2.2 mm and height 1.7 mm. The larvae relied on their yolk for nourishment before the 3rd day post hatching at (21±0.5)°C. 4 days later, the yolk sac was consumed completely and started ingesting rotifers. About 13 days after hatching, the whole body length was (7.1±0.35) mm and fin ray appeared on the dorsal fin, indicating the larvae began turned into juvenile. On day 15 post hatching, the whole body length was (7.92±0.61) mm, and golden yellow maculation occurred on each fin. On day 25, whole body length was (13.66±0.55) mm, metamorphosis was

  16. Influence of net-cage fish farming on zooplankton biomass in the Itá reservoir, SC, Brazil Influência da piscicultura em tanque-rede sobre a biomassa do zooplâncton no reservatório de Itá, SC, Brasil

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    Bruna Roque Loureiro

    2011-12-01

    Full Text Available OBJECTIVES: This study aimed to verify the influence of net-cage fish farming on zooplankton biomass in the Itá reservoir (Uruguay River, Brazil. METHODS: Samples were collected monthly from October/2009 to May/2010 at the surface and at the bottom in two sampling stations, the net-cage area and in a control area using a Van Dorn bottle and a plankton net (68 µm. RESULTS: The Cladocera and Copepoda biomass was estimated by dry weight using a micro-analytical balance, and the Rotifera biomass by Biovolume. Total zooplankton biomass varied between 6.47 and 131.56 mgDW.m-3 Calanoida copepod presented the highest value of biomass (127.56 mgDW.m-3 and rotifers, despite having an important contribution to total density, showed a maximum biomass of 2.01 mgDW.m-3. Zooplankton biomass at the net-cage area surface was higher when compared with the control area during the months of October to January. However, the zooplankton biomass was similar at the bottom of the two areas throughout the studied period. From February until May, zooplankton biomass decreased in both sampling stations, a fact probably associated with the flushing of the reservoir, followed by an increase in water transparency and a decrease in chlorophyll-a concentration in the following months (February to May. CONCLUSIONS: The influence of fish farming on zooplankton biomass was detected at the surface of the net-cage area only from October to January. From February to May this influence was not found, probably by the influence of the flushing of the reservoir.OBJETIVO: Este estudo teve o objetivo de verificar a influencia da piscicultura em tanque-rede sobre a biomassa da comunidade zooplanctônica no reservatório de Itá (Rio Uruguai, Brasil. METODOLOGIA: Foram realizadas coletas mensais de outubro/2009 a maio/2010 na superfície e no fundo em dois pontos amostrais, ponto tanque-rede e em uma área controle, com o auxílio da garrafa Van Dorn e rede de plâncton (68 µm. RESULTADOS

  17. Morphological development and growth of larval and juvenile Hexagrammos otakii%大泷六线鱼仔稚幼鱼形态发育与生长特性

    Institute of Scientific and Technical Information of China (English)

    胡发文; 郭文; 潘雷; 高凤祥; 菅玉霞; 张少春; 王雪

    2012-01-01

    2009~2011年开展了大泷六线鱼规模化人工繁育技术的研究.通过显微观察、测量、拍摄记录大泷六线鱼仔、稚、幼鱼形态发育变化,并对其生长特性、摄食习性等进行了分析.大泷六线鱼初孵仔鱼全长6.18±0.50 mm(n=60).在水温16.0±0.5℃、盐度31、光照500~1 000lx条件下,大泷六线鱼仔、稚、幼鱼生长呈现先慢后快再慢3个阶段∶0~7d生长较为缓慢,3日龄仔鱼卵黄囊尚存,少部分仔鱼开始摄食轮虫;6日龄仔鱼卵黄囊消耗殆尽,开始摄食卤虫无节幼体,进入外源性营养阶段,7d后进入快速生长期;48日龄仔鱼开始进行配合饲料转化,生长速度趋缓,并逐渐稳定.依照TL=aD3 +bD2 +cD+d的方程式对前80日龄大泷六线鱼的全长与日龄进行回归,构建生长模型∶TL(0~80)=-0.000 2D3+0.028 1D2-0.155 7D+7.376(R2=0.993 9),并根据其生长规律分别构建了0~7d、7~48d和48~80d的生长模型∶TL(0~7)=0.004 6D3-0.057 2D2+0.383 1D+6.175 1(R2=0.997 1),TL(7~48)=0.000 5D3-0.026 7D2+ 0.931D+2.269(R2=0.997 3),TL(48~80)=-0.000 1D3+0.018 7D2-0.204 5D+24.646(R2=0.999 8).%The post embryonic morphological development of Hexagrammos otakii was observed, measured and recorded by a micro cinematographic system to explore the morphological development characteristics in different stages of larval and juvenile fish. Newly hatched larvae, 6. 18 + 050 mm long and depending entirely on the egg-contained energy, were nursed at 16.0 + 0. 5℃, salinity 31, illumination 500~l 000 lx. At 3 dph (days post hatching), 7. 55 + 0. 27mm in length, with the rudimental yolk sac at abdomen, some larvae started feeding rotifers, and the development entered the exogenous feeding stage. After yolk was exhausted at 6 dph, the larvae started feeding Arternia nauplii. At 48 dph, the larvae started feeding com- pound feeds. The relationship between total length (TL) and days post hatching (D) for 0~7d,7~48d,and 48~80d fish was described

  18. Zooplankton Community Structure and Its Seasonal Variation in the Surface Water of Lugu Lake%泸沽湖表层水体浮游动物种群结构及季节变化

    Institute of Scientific and Technical Information of China (English)

    董云仙; 王忠泽

    2014-01-01

    is the deep plateau lake on the Yunnan-Guizhou Plateau with the highest latitude and alti-tude.Study of the zooplankton community in Lugu Lake was first reported in 1983 and focused on Rotifera, Copep-oda and Cladocera, but no published research has been found on the zooplankton of Lugu Lake.To characterize zo-oplankton community structure, a seasonal investigation of the zooplankton in Lugu Lake was carried out in January, April, August and November of 2010 at nine sample sites.Characteristics of the zooplankton community including structure, species composition, distribution and seasonal variation were described and the relationship of zooplankton with water quality and macrophytes were analyzed to reveal the primary factors affecting zooplankton bi-omass.Zooplankton samples for qualitative analysis were collected with a No.25 plankton net and fixed with Lugol′s solution after filtration.For quantitative analysis of protozoa and rotifers, 1 L water samples were collected 0.5 m below surface.For quantitative analysis of copepods and cladocerans, 10 L water sample were filtered with a No.25 plankton net.Counting and species identification in all samples were carried out under a microscope.A total of 80 species of zooplankton, belong to 33 families and 58 genera were observed in Lugu Lake, including Protozoa (10 families, 13 genera and 19 species), Rotifera (10 families, 22 genera and 32 species), Cladocera (4 families, 9 genera and 13 species), Copepoda (3 families, 8 genera and 10 species), and other taxa (6 families, 6 genera and 6 species) .The range of plankton densities with average number and percent contribution to total zooplankton density in parentheses were as follows:total zooplankton, 219.4-2 200.3 ind/L (813.2 ind/L, 100%);Proto-zoan, 30.0 -2 400.0 ind/L ( 660.7 ind/L, 81.25%,); Rotifera; 3.0 -780.0 ind/L, ( 145.4 ind/L, 17.88%), Cladocera, 0 -12.0 ind/L (4.1 ind/L, 0.50%); Copepoda, 0 -13.0 ind/L (2.7 ind/L, 0.33%);other taxa, 0-4.0 ind/L, (0.3 ind