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Sample records for bdelloid rotifer adineta

  1. Against All Odds: Trehalose-6-Phosphate Synthase and Trehalase Genes in the Bdelloid Rotifer Adineta vaga Were Acquired by Horizontal Gene Transfer and Are Upregulated during Desiccation.

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    Boris Hespeels

    Full Text Available The disaccharide sugar trehalose is essential for desiccation resistance in most metazoans that survive dryness; however, neither trehalose nor the enzymes involved in its metabolism have ever been detected in bdelloid rotifers despite their extreme resistance to desiccation. Here we screened the genome of the bdelloid rotifer Adineta vaga for genes involved in trehalose metabolism. We discovered a total of four putative trehalose-6-phosphate synthase (TPS and seven putative trehalase (TRE gene copies in the genome of this ameiotic organism; however, no trehalose-6-phosphate phosphatase (TPP gene or domain was detected. The four TPS copies of A. vaga appear more closely related to plant and fungi proteins, as well as to some protists, whereas the seven TRE copies fall in bacterial clades. Therefore, A. vaga likely acquired its trehalose biosynthesis and hydrolysis genes by horizontal gene transfers. Nearly all residues important for substrate binding in the predicted TPS domains are highly conserved, supporting the hypothesis that several copies of the genes might be functional. Besides, RNAseq library screening showed that trehalase genes were highly expressed compared to TPS genes, explaining probably why trehalose had not been detected in previous studies of bdelloids. A strong overexpression of their TPS genes was observed when bdelloids enter desiccation, suggesting a possible signaling role of trehalose-6-phosphate or trehalose in this process.

  2. 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

  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. Environmental DNA sequencing primers for eutardigrades and bdelloid rotifers

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    Martin Andrew P

    2009-12-01

    Full Text Available Abstract Background The time it takes to isolate individuals from environmental samples and then extract DNA from each individual is one of the problems with generating molecular data from meiofauna such as eutardigrades and bdelloid rotifers. The lack of consistent morphological information and the extreme abundance of these classes makes morphological identification of rare, or even common cryptic taxa a large and unwieldy task. This limits the ability to perform large-scale surveys of the diversity of these organisms. Here we demonstrate a culture-independent molecular survey approach that enables the generation of large amounts of eutardigrade and bdelloid rotifer sequence data directly from soil. Our PCR primers, specific to the 18s small-subunit rRNA gene, were developed for both eutardigrades and bdelloid rotifers. Results The developed primers successfully amplified DNA of their target organism from various soil DNA extracts. This was confirmed by both the BLAST similarity searches and phylogenetic analyses. Tardigrades showed much better phylogenetic resolution than bdelloids. Both groups of organisms exhibited varying levels of endemism. Conclusion The development of clade-specific primers for characterizing eutardigrades and bdelloid rotifers from environmental samples should greatly increase our ability to characterize the composition of these taxa in environmental samples. Environmental sequencing as shown here differs from other molecular survey methods in that there is no need to pre-isolate the organisms of interest from soil in order to amplify their DNA. The DNA sequences obtained from methods that do not require culturing can be identified post-hoc and placed phylogenetically as additional closely related sequences are obtained from morphologically identified conspecifics. Our non-cultured environmental sequence based approach will be able to provide a rapid and large-scale screening of the presence, absence and diversity of

  5. 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.

  6. 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.

  7. Evidence Supporting the Uptake and Genomic Incorporation of Environmental DNA in the “Ancient Asexual” Bdelloid Rotifer Philodina roseola

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    Olaf R. P. Bininda-Emonds

    2016-09-01

    Full Text Available Increasing evidence suggests that bdelloid rotifers regularly undergo horizontal gene transfer, apparently as a surrogate mechanism of genetic exchange in the absence of true sexual reproduction, in part because of their ability to withstand desiccation. We provide empirical support for this latter hypothesis using the bdelloid Philodina roseola, which we demonstrate to readily internalize environmental DNA in contrast to a representative monogonont rotifer (Brachionus rubens, which, like other monogononts, is facultative sexual and cannot withstand desiccation. In addition, environmental DNA that was more similar to the host DNA was retained more often and for a longer period of time. Indirect evidence (increased variance in the reproductive output of the untreated F1 generation suggests that environmental DNA can be incorporated into the genome during desiccation and is thus heritable. Our observed fitness effects agree with sexual theory and also occurred when the animals were desiccated in groups (thereby acting as DNA donors, but not individually, indicating the mechanism could occur in nature. Thus, although DNA uptake and its genomic incorporation appears proximally related to anhydrobiosis in bdelloids, it might also facilitate accidental genetic exchange with closely related taxa, thereby maintaining higher levels of genetic diversity than is otherwise expected for this group of “ancient asexuals”.

  8. Tolerance to X-rays and Heavy Ions (Fe, He) in the Tardigrade Richtersius coronifer and the Bdelloid Rotifer Mniobia russeola

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    Jønsson, K. Ingemar; Wojcik, Andrzej

    2017-02-01

    The aim of this study was to analyze tolerance to heavy ions in desiccated animals of the eutardigrade Richtersius coronifer and the bdelloid rotifer Mniobia russeola within the STARLIFE project. Both species were exposed to iron (Fe) and helium (He) ions at the Heavy Ion Medical Accelerator in Chiba (HIMAC) in Chiba, Japan, and to X-rays at the German Aerospace Center (DLR) in Cologne, Germany. Results show no effect of Fe and He on viability up to 7 days post-rehydration in both R. coronifer and M. russeola, while X-rays tended to reduce viability in R. coronifer at the highest doses. Mean egg production rate tended to decline with higher doses in R. coronifer for all radiation types, but the pattern was not statistically confirmed. In M. russeola, there was no such tendency for a dose response in egg production rate. These results confirm the previously reported high tolerance to high linear energy transfer (LET) radiation in tardigrades and show for the first time that bdelloid rotifers are also very tolerant to high-LET radiation. These animal phyla represent the most desiccation- and radiation-tolerant animals on Earth and provide excellent eukaryotic models for astrobiological research.

  9. Colonization of maritime glacier ice by bdelloid Rotifera.

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    Shain, Daniel H; Halldórsdóttir, Katrín; Pálsson, Finnur; Aðalgeirsdóttir, Guðfinna; Gunnarsson, Andri; Jónsson, Þorsteinn; Lang, Shirley A; Pálsson, Hlynur Skagfjörð; Steinþórssson, Sveinbjörn; Arnason, Einar

    2016-05-01

    Very few animal taxa are known to reside permanently in glacier ice/snow. Here we report the widespread colonization of Icelandic glaciers and ice fields by species of bdelloid Rotifera. Specimens were collected within the accumulation zones of Langjökull and Vatnajökull ice caps, among the largest European ice masses. Rotifers reached densities up to ∼100 individuals per liter-equivalent of glacier ice/snow, and were freeze-tolerant. Phylogenetic analyses indicate that glacier rotifers are polyphyletic, with independent ancestries occurring within the Pleistocene. Collectively, these data identify a previously undescribed environmental niche for bdelloid rotifers and suggest their presence in comparable habitats worldwide.

  10. 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

  11. A checklist of the freshwater rotifer fauna of Thailand (Rotifera, Monogononta, Bdelloidea

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    Phannee Sa-Ardrit

    2013-08-01

    Full Text Available We provide a checklist of the freshwater Rotifera recorded from Thailand, based on a review of available literature. Approximately 398 species of rotifers are recorded. The rotifer fauna of Thailand has been investigated quite comprehensively and these studies focus on four main parts of the country: the northern, north-eastern, central and southern. The number of rotifers on record is the highest in the north-eastern part (275, followed by the southern part (261, the central part (182 and the northern part (115. The majority of Thai Rotifera belongs to family Lecanidae (24.4%, Lepadellidae (11.3%, Brachionidae (11.1%, Trichocercidae (9.0% and Flosculariidae (9.0%. The most diverse genus is Lecane followed by Trichocerca, Lepadella and Brachionus. Although most Thai rotifers are cosmopolitan, there are a number of Oriental endemics, including some strict Thai or regional endemics. Illoricate rotifers and bdelloids are understudied, while experimental and molecular approaches promise to add most to our knowledge and understanding of the role of rotifers in ecosystem functioning.

  12. Resurrecting Van Leeuwenhoek's rotifers: a reappraisal of the role of disaccharides in anhydrobiosis.

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    Tunnacliffe, A; Lapinski, J

    2003-10-29

    In 1702, Van Leeuwenhoek was the first to describe the phenomenon of anhydrobiosis in a species of bdelloid rotifer, Philodina roseola. It is the purpose of this review to examine what has been learned since then about the extreme desiccation tolerance in rotifers and how this compares with our understanding of anhydrobiosis in other organisms. Remarkably, much of what is known today about the requirements for successful anhydrobiosis, and the degree of biostability conferred by the dry state, was already determined in principle by the time of Spallanzani in the late 18th century. Most modern research on anhydrobiosis has emphasized the importance of the non-reducing disaccharides trehalose and sucrose, one or other sugar being present at high concentrations during desiccation of anhydrobiotic nematodes, brine shrimp cysts, bakers' yeast, resurrection plants and plant seeds. These sugars are proposed to act as water replacement molecules, and as thermodynamic and kinetic stabilizers of biomolecules and membranes. In apparent contradiction of the prevailing models, recent experiments from our laboratory show that bdelloid rotifers undergo anhydrobiosis without producing trehalose or any analogous molecule. This has prompted us to critically re-examine the association of disaccharides with anhydrobiosis in the literature. Surprisingly, current hypotheses are based almost entirely on in vitro data: there is very limited information which is more than simply correlative in the literature on living systems. In many species, disaccharide accumulation occurs at approximately the same time as desiccation tolerance is acquired. However, several studies indicate that these sugars are not sufficient for anhydrobiosis; furthermore, there is no conclusive evidence, through mutagenesis or functional knockout experiments, for example, that sugars are necessary for anhydrobiosis. Indeed, some plant seeds and micro-organisms, like the rotifer, exhibit excellent desiccation

  13. 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

  14. 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

  15. A mitogenomic re-evaluation of the bdelloid phylogeny and relationships among the Syndermata.

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    Erica Lasek-Nesselquist

    Full Text Available Molecular and morphological data regarding the relationships among the three classes of Rotifera (Bdelloidea, Seisonidea, and Monogononta and the phylum Acanthocephala are inconclusive. In particular, Bdelloidea lacks molecular-based phylogenetic appraisal. I obtained coding sequences from the mitochondrial genomes of twelve bdelloids and two monogononts to explore the molecular phylogeny of Bdelloidea and provide insight into the relationships among lineages of Syndermata (Rotifera + Acanthocephala. With additional sequences taken from previously published mitochondrial genomes, the total dataset included nine species of bdelloids, three species of monogononts, and two species of acanthocephalans. A supermatrix of these 10-12 mitochondrial proteins consistently recovered a bdelloid phylogeny that questions the validity of a generally accepted classification scheme despite different methods of inference and various parameter adjustments. Specifically, results showed that neither the family Philodinidae nor the order Philodinida are monophyletic as currently defined. The application of a similar analytical strategy to assess syndermate relationships recovered either a tree with Bdelloidea and Monogononta as sister taxa (Eurotatoria or Bdelloidea and Acanthocephala as sister taxa (Lemniscea. Both outgroup choice and method of inference affected the topological outcome emphasizing the need for sequences from more closely related outgroups and more sophisticated methods of analysis that can account for the complexity of the data.

  16. MANAJEMEN KULTUR ROTIFER DENGAN TANGKI VOLUME KECIL

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    Philip Teguh Imanto

    2009-04-01

    Full Text Available Keberhasilan pembenihan ikan sangat dipengaruhi keberhasilan produksi jasad pakan rotifer secara tepat dan efisien. Penelitian kultur rotifer dengan tangki volume kecil bertujuan untuk mendapatkan efisiensi produksi yang paling optimal dan memenuhi prinsip dasar akuakultur low volume high density. Penelitian menggunakan tangki polyethylene dengan volume 500 L dan volume media awal 100 L, padat tebar awal 200 ind. rotifer per mL dengan sediaan pakan dasar fitoplankton Nannocloropsis occulata, ragi roti (0,05 g/mio.rot./feeding dan suplemen Scott emulsion (0,005 g/mio.rot./feeding. Penelitian dilakukan secara bertahap; tahap pertama (I tanpa penambahan air laut, peningkatan volume hanya dari penambahan 15 L Nannochloropsis tiap hari sampai hari kelima, tahap kedua (II dengan penambahan alga 40 L dan air laut 40 L; serta tahap ketiga (III dengan menggandakan pemberian ragi roti. Hasil penelitian menunjukkan bahwa pada percobaan tahap I: total produksi rata-rata 122,37 x 106 ind. rotifer, pada tahap II: 97,67 x 106 ind. rotifer, dan pada tahap III: dicapai rata-rata total produksi tertinggi dengan 187,17 x 106 ind. rotifer per tanki kultur 500 L. Pengelolaan kultur pada tahap III memberikan hasil terbaik dengan simpangan terkecil antar tangki kultur ulangan, dan membuktikan sebagai pengelolaan terbaik untuk kultur rotifer dengan tangki volume kecil.  Success of marine seed production is highly influenced by effective and efficient production performance of life food rotifer. Observation on rotifer culture using small volume tank was aimed to get the optimum production and efficiency, to fulfill the basic principle of aquaculture “low volume high density”. Polyethylene tanks of 500 L. were used as culture container, with initial 100 liter sea water as culture medium and initial density of 200 ind. rotifer per mL. N. occulata, baker yeast (0.05 g/mio.rotifer/feeding and Scott emulsion (0.005 g/mio.rotifer/feeding were used as basic feed, and

  17. Freshwater rotifers from Hordaland, western Norway, with a survey of freshwater rotifers previously found in Norway

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    Brit Godske Bjørklund

    2010-01-01

    Full Text Available   Bjørklund BG. 2009. Freshwater rotifers from Hordaland western Norway with a u survey of freshwater rotifers previously found in Norway. Fauna Norvegica29: 11-54. A total of 156 species (or subspecies o rotifers, mostly non-planktonic, have been identified from freshwater or slightly brackish-water localities in the county of Hordaland; 83 are new to Norway and 24 others are new to the county. One hundred of the species were collected from the two valleys of Eksingedalen and Teigdalen in spring and summer 1967. Samples were taken on the shallow shores of lake-like parts of the rivers, and in pools, tarns and small lakes. Forty more or less euryhaline fresh­water rotifers were also collected during studies of slightly brackish-water localities around Bergen in 1963-1969. A number of freshwater rotifers were collected at several localities in and around Bergen in 1968-1970, and on the western part of Hardangervidda. Of those so far identified ,23 are new to Norway and 8 more are new to the county. They are therefore included in the species list. A few additional ones are referred to in the taxonomical notes. All the species are listed with localities and habitat categories, or, in the case of the last-mentioned ones, just the district where they were collected. The paper includes notes, measurements and ,in most cases, figures regarding 44 little known, variable or taxonomically problematical species, especially in the genera Cephalodella and Trichocerca. Comments are given on the distribution , abundance and diversity of the species. The paper presents asurvey of previous investigations on rotifers in Norway, listing 200 previously recorded freshwater (a few euryhaline rotifers, giving other names, the authors who recorded the finds and, in most cases, the counties where the species were collected. 

  18. Rotifers as experimental tools for investigating aging

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    Snell, Terry W.; Johnston, Rachel K.; Gribble, Kristin E.; Mark Welch, David B.

    2015-01-01

    Comparative biogerontology has much to contribute to the study of aging. A broad range of aging rates have evolved to meet environmental challenges, and understanding these adaptations can produce valuable insights into aging. The supra Phylum Lophotrochozoa is particularly understudied and has several groups that have intriguing patterns of aging. Members of the Lophotrochozoan phylum Rotifera are particularly useful for aging studies because cohort life tables can be conducted with them easily, and biochemical and genomic tools are available for examining aging mechanisms. This paper reviews a variety of caloric restriction (CR) regimens, small molecule inhibitors, and dietary supplements that extend rotifer lifespan, as well as important interactions between CR and genotype, antioxidant supplements, and TOR and jun-N-terminal kinase (JNK) pathways, and the use of RNAi to identify key genes involved in modulating the aging response. Examples of how rapamycin and JNK inhibitor exposure keeps mortality rates low during the reproductive phase of the life cycle are presented, and the ease of conducting life table experiments to screen natural products from red algae for life extending effects is illustrated. Finally, experimental evolution to produce longer-lived rotifer individuals is demonstrated, and future directions to determine the genetic basis of aging are discussed. PMID:25642019

  19. [Community structure of planktonic rotifers in the Pearl River Delta].

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    Gao, Yuan; Li, Xin-Hui; Lai, Zi-Ni; Yu, Jing; Wang, Chao; Zeng, Yan-Yi; Liu, Qian-Fu; Yang, Wan-Ling

    2014-07-01

    Four ecological investigations were carried out on planktonic rotifers in Pearl River Delta in 2012. The community structure, including spatial and temporal patterns of species composition, dominant species, biomass and biodiversity, was investigated. The correlation between the community structure of rotifers and the environmental factors was discussed. Moreover, the aggregation structures of rotifers were analyzed. A total of 53 rotifer species were found. Dominant species changed markedly with season and space. Polyarthra trigla had higher dominance. In terms of seasonal changes, the density and biomass were higher in dry season than in wet season, while the biodiversity and evenness indices were vice versa. The biomass and biodiversity of rotifers showed highly significant differences among seasons. In terms of spatial distribution, the average density and the average biomass showed an increase from the southwest to the northeast. The highest density and biomass were recorded in Shiqiao. The biodiversity and evenness indices had an opposite spatial distribution, with the highest values being recorded in Qingqi. The rotifer density was significantly different among the investigated sites, while the biomass and biodiversity were not significantly different. Correlation analysis demonstrated a highly significant positive correlation between rotifer density and biomass, as well as between biodiversity and evenness indices, and a highly negative correlation between biodiversity and biomass. The biodiversity and evenness indices both decreased markedly with the increase of biomass. Principal component analysis indicated that the rotifer density was closely correlated with environment factors, such as water temperature, pH, dissolved oxy- gen, chlorophyll a content, total phosphorus, and total nitrogen, in different seasons. Aggregation analysis based on rotifer density revealed five aggregation structures in the investigated sites, indicating significant differences

  20. Impact of arachidonic acid enrichment of live rotifer prey on bacterial communities in rotifer and larval fish cultures.

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    Seychelles, Laurent H; Doiron, Kim; Audet, Céline; Tremblay, Réjean; Pernet, Fabrice; Lemarchand, Karine

    2013-03-01

    Rotifers (Brachionus plicatilis), commonly used at first feeding in commercial fish hatcheries, carry a large bacteria load. Because they are relatively poor in essential fatty acids, it is common practice to enrich them with fatty acids, including arachidonic acid (AA). This study aims to determine whether prey enrichment with AA may act as a prebiotic and modify the microbial community composition either in AA-enriched rotifer cultures or in larval-rearing water using winter flounder (Pseudopleuronectes americanus) as a larval fish model. AA enrichment modified the bacterial community composition in both the rotifer culture tanks and the larval-rearing tanks. We observed an increase in the number of cultivable bacteria on TCBS (thiosulfate-citrate-bile salts-sucrose) agar, used as a proxy for the abundance of Vibrio sp. The results suggest that AA may also play an indirect role in larval health.

  1. Identification key to the genera of marine rotifers worldwide

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    Fontaneto, D; De Smet, W.H.; Melone, G.

    2008-01-01

    A dichotomous key to rotifers is presented for the 28 Families and 66 Genera that have been reported from saline systems of both marine and inland waters. Information is provided on general identification and papers dealing more particularly with certain Families and Genera. A succinct overview of the species found in saline habitats is given for each genus.

  2. 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.

  3. 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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  5. Investigation of a rotifer (Brachionus calyciflorus) - green alga (Scenedesmus pectinatus) interaction under non- and nutrient-limited conditions

    NARCIS (Netherlands)

    Lürling, M.F.L.L.W.

    2006-01-01

    Two-day life cycle tests with the rotifer Brachiomus calyciflorus were run to study the nutritional quality effects to rotifers of Scenedesmus pectinatus grown under non-limiting nitrogen limiting and phosphorus limiting conditions and the feedback of the rotifers oil the Food algae. Under nutrient-

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

    Science.gov (United States)

    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.

  7. 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

    Directory of Open Access Journals (Sweden)

    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.

  8. A Parasite of Marine Rotifers: A New Lineage of Dinokaryotic Dinoflagellates (Dinophyceae

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    Fernando Gómez

    2015-01-01

    Full Text Available Dinoflagellate infections have been reported for different protistan and animal hosts. We report, for the first time, the association between a dinoflagellate parasite and a rotifer host, tentatively Synchaeta sp. (Rotifera, collected from the port of Valencia, NW Mediterranean Sea. The rotifer contained a sporangium with 100–200 thecate dinospores that develop synchronically through palintomic sporogenesis. This undescribed dinoflagellate forms a new and divergent fast-evolved lineage that branches among the dinokaryotic dinoflagellates.

  9. The process-dependent impacts of dimethoate on the feeding behavior of rotifer.

    Science.gov (United States)

    Chen, Jianqiu; Guo, Ruixin

    2015-01-01

    Traditional toxicological studies usually depict the dose-effect relationship at the given exposure time while ignore how toxic effects vary during and after the exposure. In the present study, feeding depression of the rotifer Brachionus calyciflorus under the impact of dimethoate was evaluated not only in the exposure time but also in the post-exposure time. Both the filtration rates (F) and the ingestion rates (I) of the rotifers varied during the exposure period under any concentration of dimethoate. A three-stepwise stress was observed when the rotifers were exposed to 0.2 and 1.0 mg L(-1) of the pesticide respectively, whereas 1.8 mg L(-1) dimethoate caused only one-step stress on the rotifers during the whole period. In addition, although the feeding behaviors of the rotifers recovered after the exposure, two feeding rates both got even more depressed at 8h in the post-exposure time. The latent inhibition after exposure was related to the exposure concentrations and the exposure time. Our works indicated that the impact of dimethoate on the feeding behavior of the rotifers was highly process-dependent that caused the stepwise stress during the exposure period and the latent stress after the exposure.

  10. 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.

  11. Assessing the impacts of dimethoate on rotifers' reproduction through the pre-exposure history.

    Science.gov (United States)

    Guo, Ruixin; Chen, Jianqiu

    2015-01-01

    Organism usually undergoes an exposure of environmental pollution after a maternal exposure before birth. Traditional toxicological studies often initiated with rotifer neonates derived from the unexposed mothers while ignoring the pre-exposure (maternal exposure). The present study assessed the effect of dimethoate on the reproduction of the rotifer Brachionus calyciflorus, considering how the pre-exposure occurred in the parental generation influenced the subsequent impact. The F0 generation rotifers were exposed to the pesticide at five concentrations until the first F1 generation rotifers were reproduced. The neonates (F1 generation) were then exposed to the pesticide at the corresponding concentrations. The offspring reproduction, the time begins to reproduce, the duration of the reproductive period and the lifespan of the F1 generation rotifers were evaluated. Our results indicated that dimethoate influenced the maturation and reproduction of the rotifers. The highest concentration (1.8 mg L(-1)) of dimethoate caused an inhibition in the offspring reproduction, shortened the life span and reduced the duration of the reproductive period. In addition, of particular interest in our study was that reproduction is also accelerated by the lowest concentration (0.2 mg L(-1)). However, the pre-exposure had a significant effect on the subsequent impact. The dimethoate pre-exposure increased the impacts when the F1 generation rotifers were exposed to the substance, even at the same concentrations as in pre-exposure. It suggests that the maternal exposure history before birth is also important and has the long-lasting consequence from one generation to another.

  12. 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.

  13. 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

    -antagonistic mutant. P. gallaeciensis was readily established in axenic cultures of the two microalgae Tetraselmis suecica and Nannochloropsis oculata, and of the rotifer Brachionus plicatilis. P. gallaeciensis reached densities of 10(7) cfu/ml and did not adversely affect growth of algae or rotifers. Vibrio...

  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. Measurement of Survival Time in Brachionus Rotifers: Synchronization of Maternal Conditions.

    Science.gov (United States)

    Kaneko, Gen; Yoshinaga, Tatsuki; Gribble, Kristin E; Welch, David M; Ushio, Hideki

    2016-07-22

    Rotifers are microscopic cosmopolitan zooplankton used as models in ecotoxicological and aging studies due to their several advantages such as short lifespan, ease of culture, and parthenogenesis that enables clonal culture. However, caution is required when measuring their survival time as it is affected by maternal age and maternal feeding conditions. Here we provide a protocol for powerful and reproducible measurement of the survival time in Brachionus rotifers following a careful synchronization of culture conditions over several generations. Empirically, poor synchronization results in early mortality and a gradual decrease in survival rate, thus resulting in weak statistical power. Indeed, under such conditions, calorie restriction (CR) failed to significantly extend the lifespan of B. plicatilis although CR-induced longevity has been demonstrated with well-synchronized rotifer samples in past and present studies. This protocol is probably useful for other invertebrate models, including the fruitfly Drosophila melanogaster and the nematode Caenorhabditis elegans, because maternal age effects have also been reported in these species.

  16. Assessment the toxic effects of dimethoate to rotifer using swimming behavior.

    Science.gov (United States)

    Guo, Ruixin; Ren, Xinkun; Ren, Hongqiang

    2012-09-01

    The toxic effects of the common organophosphorus pesticide dimethoate on freshwater zooplankton Brachionus calyciflorus (rotifer) were tested. Because of the advantages of behavioral response in environmental monitoring, swimming behavior was used as the endpoint in this research. After exposure 6 h at five dimethoate concentrations (0.18, 0.53, 0.88, 1.23 and 1.59 mg·L(-1)), the pesticide disrupted the balance in rotifer swimming direction and caused an obvious direction preference. It also inhibited significantly the swimming angular and linear speed. Our results showed that dimethoate has a sublethal toxic effect on this aquatic invertebrate.

  17. 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. 

  18. Comparative toxicant sensitivity of sexual and asexual reproduction in the rotifer Brachionus calyciflorus

    Energy Technology Data Exchange (ETDEWEB)

    Snell, T.W. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Biology; Carmona, M.J. [Univ. de Valencia (Spain). Area de Ecologia

    1995-03-01

    Cyclically parthenogenetic zooplankters like rotifers are important tools for assessing toxicity in aquatic environments. Sexual reproduction is an essential component of rotifer life cycles, but current toxicity tests utilize only asexual reproduction. The authors compared the effects of four toxicants on asexual and sexual reproduction of the rotifer Brachionus calyciflorus. Toxicants had a differential effect on sexual and asexual reproduction, with sexual reproduction consistently the most sensitive. Concentrations of 0.2 {mu}g/ml PCP (sodium pentachlorophenate) had no effect on the asexual reproductive rate, but significantly reduced sexual reproduction. Likewise, chlorpyrifos concentrations of 0.3 {mu}g/ml had no significant effect on asexual reproduction, but sexual reproduction was significantly reduced. There was no difference in NOECs, LOECs, and chronic values for asexual and sexual reproduction for cadmium and naphthol tests. However, comparison of toxicant effect levels revealed that sexual reproduction was more strongly reduced at each toxicant concentration. The four toxicants tested inhibited sexual reproduction 2 to 68 times more than asexual reproduction at the lowest observed effect concentrations. Toxicants inhibited sexual reproduction in its initial step: sexual female production. Because sexual reproduction is more sensitive, toxicity tests based exclusively on asexual reproduction may not be protective of rotifer life cycles.

  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. 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.

  1. 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...

  2. Use of Lecane rotifers for limiting Thiothrix filamentous bacteria in bulking activated sludge in a dairy wastewater treatment plant

    Directory of Open Access Journals (Sweden)

    Kowalska Ewa

    2014-01-01

    Full Text Available Excessive growth of filamentous bacteria is a serious problem in many dairy wastewater treatment plants (WWTPs. The objective of the study was to determine whether Lecane inermis rotifers were able to reduce the density of Thiothrix bacteria in activated sludge originating from a dairy WWTP, as well as to identify the impact of rotifers on other organisms in sludge. On a laboratory scale, three experiments were conducted in which activated sludge with a predominance of Thiothrix was inoculated with rotifers at an initial concentration of app. 600 individuals/mL. The results showed that the rotifers, by feeding on the bacterium filaments, are able to reduce significantly the quantity of Thiothrix. A decline in Thiothrix abundance coincided with an improvement of the sedimentation properties of activated sludge. In addition, it was proven that Lecane inermis did not negatively affect the number of Protozoa and Metazoa in activated sludge.

  3. The swimming speed alteration of two freshwater rotifers Brachionus calyciflorus and Asplanchna brightwelli under dimethoate stress.

    Science.gov (United States)

    Chen, Jianqiu; Wang, Zhiliang; Li, Guoping; Guo, Ruixin

    2014-01-01

    Two common freshwater rotifer species Brachionus calyciflorus and Asplanchna brightwelli were employed as test organisms to investigate the toxic effects of the widely used organophosphate pesticide, dimethoate. The swimming angular speed and linear speed alteration of two rotifers were evaluated under the toxic stress in four concentrations (0.4, 0.8, 1.2, and 1.6 mg L(-1)). For B. calyciflorus, the rotifer swimming angular speed and linear speed were both adversely affected as a function of the toxicant concentrations. After a 2h exposure, the angular speeds at four concentrations were 39.37, 30.74, 26.68 and 23.96° s(-1), 65.30%, 50.98%, 44.25% and 39.74% of that of the control, respectively, while the mean linear speed decreased from 194.80 to 91.85×10(-3) mm s(-1), which was 70.12%, 48.14%, 34.02% and 33.06% of that of the control (277.82×10(-3) mm s(-1)), respectively. The pesticide also significantly inhibited the swimming angular speed of A. brightwelli. After a 2h exposure, the angular speeds of this rotifer at four concentrations were 39.37, 30.74, 26.68 and 23.96° s(-1), only 22.99%, 17.16%, 16.21% and 13.63% of that of the control (170.80° s(-1)), respectively. Compared with the results of B. calyciflorus, A. brightwelli was more sensitive on the swimming angular speed when exposed to the toxicant. It implied that A. brightwelli should be an alternative candidate model species about the toxicities of aquatic pollutants. In addition, when the rotifer A. brightwelli was exposed to four pesticide concentrations, the swimming linear speed displayed symptoms of hormesis, characterized by the conversion of low-concentration stimulate to high-concentration inhibition. Our results show that dimethoate had a significant effect on swimming of freshwater rotifers.

  4. 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.

  5. 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.

  6. 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. 

  7. The effect of seasonality on the structure of rotifers in a black-water shallow lake in Central Amazonia

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    CLARICE C. NOVA

    2014-09-01

    Full Text Available Rotifers have often been used as indicators of sudden changes in physical and chemical features of the aquatic environment. Such features vary greatly during flood pulse events in small lakes connected to major floodplains. However, few are the studies that investigate the consequences of the flood pulse in rotifer species composition, abundance, richness and diversity, especially in Amazonian lakes. We analyzed samples from a small blackwater lake of an “igarapé” connected permanently to the Negro river, in Central Amazonia. Samples were taken twice a year for two years, comprising flooding and receding periods of the flood pulse. Rotifer abundance increased significantly after draught events, and electrical conductivity and turbidity were intrinsically related to such variation. Species composition also changed from flooding to receding periods. Some taxa, such as Brachionus zahniseri reductus and Lecane remanei were restricted to receding periods, while Brachionus zahniseri, Brachionus gillardi and Lecane proiecta were only present during flooding. A shift in the composition of rotifer families was observed from one period to another, showing the effect of renewing waters of the flood pulse. These results suggest that the flood pulse acts as a driving force and stressing condition, considerably altering rotifer community dynamics, either changing species composition or decreasing abundance.

  8. Population density, sexual reproduction and diapause in monogonont rotifers: new data for Brachionus and a review

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    John J. GILBERT

    2004-09-01

    Full Text Available Diapausing, fertilized eggs in monogonont rotifers typically are formed after an environmental signal induces amictic females to produce mictic daughters. Mictic females lay haploid eggs that may develop parthenogenetically into males, or that may be fertilized and develop into diapausing, female embryos called resting eggs. Laboratory experiments demonstrate that crowding is the signal for production of mictic females in strains of Brachionus calyciflorus from Texas, Spain and Germany, and in a strain of Brachionus variabilis from Spain. In these experiments, newborn amictic females were cultured singly in large and small volumes to give lowand high-density treatments. Therefore, the induction of mictic females is due exclusively to population density and cannot be attributed to a grouping effect involving some interaction among individuals. B. variabilis is very sensitive to population density; females had to be cultured in 30 ml to prevent appreciable production of mictic daughters. Crowding is now known to be the signal for initiation of sexuality and diapause in four species of Brachionus, two species of Epiphanes, and Rhinoglena frontalis. The chemical that mediates this response somehow influences oocytes in the maternal body cavity to differentiate into mictic females. Aggregation of individuals in natural systems may facilitate the production of mictic females. In some of these rotifers, the response to crowding is suppressed in early generations from the resting egg, assuring that clonal populations will attain higher population densities before committing to sexual reproduction. Fitness benefits of the mictic-female response to crowding, and to other environmental signals in other rotifers (dietary tocopherol, long photoperiod, are discussed.

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

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    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.

  10. Application of the minute monogonont rotifer proales similis de Beauchamp in larval rearing of seven-band grouper epinephelus septemfasciatus

    OpenAIRE

    2011-01-01

    In comparison to the rotifer Brachionus rotundiformis, the euryhaline rotifer Proales similis has a much smaller body size (83μm in length and 40μm in width), and it may be applicable as live food for rearing marine fish larvae with a very small mouth size. A mass culture technique of P. similis was recently established, and it has already been confirmed that marine fish larvae could ingest P. similis. In the present study, we further investigated the use of P. similis as an initial food by o...

  11. Biodiversity of freshwater rotifers (Rotifera: Eurotatoria of Mizoram, Northeast India: composition, new records and interesting features

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    Bhushan Kumar Sharma

    2015-10-01

    Full Text Available The plankton and semi-plankton samples examined from Mizoram state of northeast India (NEI revealed speciose and diverse Rotifera assemblage including a total richness (S of 162 species belonging to 19 families and 35 genera. The reports of six species new to India, four species new to NEI and 76 new records to Mizoram merit biodiversity interest. The occurrence of one Australasian, one Oriental, seven Paleotropical, one Holarctic, one cosmo (sub tropical and five other interesting species imparts biogeographical value while several species indicate regional distribution importance. Lecanidae > Lepadellidae > Brachionidae > Trichocercidae collectively comprised 69.7% of total richness (S. Lecane > Lepadella > Trichocerca are diverse genera (~52.0% of S while Brachionus spp. (~8.0% deserve cautious mention. The rotifer diversity pattern is predominantly ‘tropical’ with a large component of cosmopolitans (~71.0% of S while tropicopolitan and pantropical species contributed ~16.0%. This study indicated high richness of the littoral-periphytonic and relative paucity of planktonic taxa. Analysis of periphytic, sessile, colonial and benthic taxa, and of cryptic diversity in certain species-groups merit attention for further biodiversity update and we estimate occurrence of 250+ rotifer species in Mizoram.

  12. Successful Replacement of Artemia salina nauplii with Marine Rotifers (Brachionus plicatilis) in the Diet of Preadult Zebrafish (Danio rerio).

    Science.gov (United States)

    Lawrence, Christian; James, Althea; Mobley, Scottie

    2015-10-01

    Previously established rearing protocols for zebrafish begin feeding with marine rotifers (Brachionus plicatilis), followed by Artemia nauplii until the fish reach subadult stage, the developmental time point at which they can be most easily transitioned onto a processed diet. However, the inclusion of Artemia is less than ideal, given its fluctuating availability and high costs. We tested whether or not we could replace Artemia with rotifers during our normal rearing sequence and still meet published performance standards for (i) weaning fish onto a processed diet by 25 days postfertilization (dpf) and (ii) successful breeding by 60 dpf. Here, we present the results of trials where wild-type and casper zebrafish were fed exclusively with rotifers (R) or rotifers followed by Artemia (RA) for the first 25 dpf after which point all fish were transitioned to a processed diet (Gemma Micro 300). We measured growth and survival at days 25 and 60, and tested for reproductive capability at 60 dpf. While growth performance was significantly better in the RA groups, we were still able to meet goals for both weaning and generation time in the R groups without compromising survival or sex ratios.

  13. Species composition and abundance of rotifers in different environments of the floodplain of the upper Paraná river, Brazil

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    Aparecida Paula Perez Garcia

    1998-01-01

    Full Text Available The purpose of this study was to describe the composition and abundance of rotifers in different environments: one lotie (the Ivinheima River and another lentic (the Patos Lake located in the floodplain of the Upper Paraná River. The influence of limnological variables on the structure and dynamics of rotifers was also examined. Samples were taken monthly from March 1992 through February 1993, in the open water region of the lake and river and in the channel between them and, in the littoral region of the lake and river. Of the 96 species identified, the best represented families were: Brachionidae (20 species, Lecanidae (18 species, and Trichocercidae (15 species. 55 species were widely distributed, 13 were pantropical, 16 neotropical (8 endemic to South America. Trichocerca gracilis was a new record for this floodplain. Dipleuchlanis propatula propatula, Lecane curvicornis, L. leontina, L. bulla, Plationus patulus patulus, Platyias quadricornis quadricornis, Testudinella patina, and T. mucronata hauriensis were consistently present. More species were recorded during the high water period, probably because of the interconnection among the different environments of the floodplain that allows fauna exchange and an increase in available habitats. Rotifer densities were higher mainly in the lake, during the high water. Using principal components analysis, was identified four variables that influence the seasonal variation in the rotifer densities: water level, dissolved oxygen, chlorophyll-a concentration, and water temperature.

  14. 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

  15. Determination of trace elements in freshwater rotifers and ciliates by total reflection X-ray fluorescence spectrometry

    Science.gov (United States)

    Woelfl, S.; Óvári, M.; Nimptsch, J.; Neu, T. R.; Mages, M.

    2016-02-01

    Element determination in plankton is important for the assessment of metal contamination of aquatic environments. Until recently, it has been difficult to determine elemental content in rotifers or ciliates derived from natural plankton samples because of the difficulty in handling and separation of these fragile organisms. The aim of this study was to evaluate methods for separation of rotifers and large ciliates from natural plankton samples (μg range dry weight) and subsequent analysis of their elemental content using total-reflection X-ray fluorescence spectrometry (TXRF). Plankton samples were collected from different aquatic environments (three lakes, one river) in Chile, Argentina and Hungary. From one to eighty specimens of five rotifer species (Brachionus calyciflorus, Brachionus falcatus, Asplanchna sieboldii, Asplanchna sp., Philodina sp.) and four to twelve specimens of one large ciliate (Stentor amethystinus) were prepared according to the dry method originally developed for microcrustaceans, and analysed by TRXF following in situ microdigestion. Our results demonstrated that it possible to process these small and fragile organisms (individual dry mass: 0.17-9.39 μg ind- 1) via careful washing and preparation procedures. We found species-dependent differences of the element mass fractions for some of the elements studied (Cr, Mn, Fe, Ni, Cu, Zn, As, Pb), especially for Cu, Fe and Mn. One large rotifer species (A. sieboldii) also showed a negative correlation between individual dry weight and the element content for Pb, Ni and Cr. We conclude that our application of the in situ microdigestion-TRXF method is suitable even for rotifers and ciliates, greatly expanding the possibilities for use of plankton in biomonitoring of metal contamination in aquatic environments.

  16. Response of soil nematodes, rotifers and tardigrades to three levels of season-long sulfur dioxide exposures

    Energy Technology Data Exchange (ETDEWEB)

    Leetham, J.W.; McNary, T.J.; Dodd, J.L.; Lauenroth, W.K.

    1982-05-01

    Soil nematode, rotifer, and tardigrade populations were sampled in field plots of native northern mixed prairie in southeastern Montana from 1977 to 1979. The field plots were exposed to season-long fumigation with controlled low-levels of SO/sub 2/ throughout the growing seasons (April-October). Two field sites were used, one fumigated for five seasons (1975-1979) and the other for four (1976-1979). Seasonal average SO/sub 2/ concentrations ranged from control (< 1 pphm) to approximately 7 pphm. Soil fauna were sampled by taking soil cores and extracting them by the Baermann wet funnel technique.Total counts were made for tardigrades and rotifers while nematodes were divided into three groups - stylet bearers (Tylenchida-Dorylimida), non-stylet bearers, and the predatory Mononchida. Consistent trends of substantial reductions in tardigrade populations occurred in all treated plots in all years; however, statistical significance was achieved only in 1979 when sample size and individual core size were substantially increased. Tardigrades were found to be restricted almost completely to the surface two centimeters of the soil profile. Significant population reductions in the treated plots of both sites were found for non-stylet bearing nematodes in 1977 only. Stylet bearing types and predaceous Mononchida appeared unaffected by the SO/sub 2/ as were the soil rotifers, although slight but consistent trends of reduction in rotifers occurred in the highest treatments in 1977 and 1978. Both nematodes and rotifers were distributed primarily in the 0 to 10 cm layer of the soil profile but not restricted to the soil surface as much as the tardigrades. Implications of the responses to SO/sub 2/ and vertical distributions of the three groups are discussed.

  17. Discovering genes associated with dormancy in the monogonont rotifer Brachionus plicatilis

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    Kube Michael

    2009-03-01

    Full Text Available Abstract Background Microscopic monogonont rotifers, including the euryhaline species Brachionus plicatilis, are typically found in water bodies where environmental factors restrict population growth to short periods lasting days or months. The survival of the population is ensured via the production of resting eggs that show a remarkable tolerance to unfavorable conditions and remain viable for decades. The aim of this study was to generate Expressed Sequence Tags (ESTs for molecular characterisation of processes associated with the formation of resting eggs, their survival during dormancy and hatching. Results Four normalized and four subtractive libraries were constructed to provide a resource for rotifer transcriptomics associated with resting-egg formation, storage and hatching. A total of 47,926 sequences were assembled into 18,000 putative transcripts and analyzed using both Blast and GO annotation. About 28–55% (depending on the library of the clones produced significant matches against the Swissprot and Trembl databases. Genes known to be associated with desiccation tolerance during dormancy in other organisms were identified in the EST libraries. These included genes associated with antioxidant activity, low molecular weight heat shock proteins and Late Embryonic Abundant (LEA proteins. Real-time PCR confirmed that LEA transcripts, small heat-shock proteins and some antioxidant genes were upregulated in resting eggs, therefore suggesting that desiccation tolerance is a characteristic feature of resting eggs even though they do not necessarily fully desiccate during dormancy. The role of trehalose in resting-egg formation and survival remains unclear since there was no significant difference between resting-egg producing females and amictic females in the expression of the tps-1 gene. In view of the absence of vitellogenin transcripts, matches to lipoprotein lipase proteins suggest that, similar to the situation in dipterans, these

  18. Deepor Beel revisited: new records of rotifers (Rotifera: Eurotatoria with remarks on interesting species

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    B.K. Sharma

    2011-01-01

    Full Text Available Plankton samples collected (April 2009 - March 2010 from Deepor Beel, a Ramsar site, revealed 21 species of the Phylum Rotifera belonging to 12 genera and eight families as new records. Amongst these, Brachionus durgae is a new record for northeastern India. The recorded species included the Australasian Brachionus dichotomus reductus and Notommata spinata; two Oriental endemics, namely, Keratella edmondsoni and Lecane blachei while Lecane lateralis, L haliclysta, Lepadella benjamini, Platyias leloupi, Mytilina acanthophora, Macrochaetus longipes, Trichocerca bicristata and T. flagellata are examples of regional distribution interest. The present report increases the number of species recorded from this important wetland of northeastern India to 134 species which, in turn, is the richest rotifer diversity known till date from any aquatic ecosystem of South Asia.

  19. Syltodinium listii gen. et spec. nov., a marine ectoparasitic dinoflagellate on eggs of copepods and rotifers

    Science.gov (United States)

    Drebes, Gerhard

    1988-09-01

    Syltodinium listii is described as a new marine ectoparasitic dinoflagellate. In culture experiments the species was found feeding on eggs of planktonic copepods and rotifers. The dinospore penetrates the host by a peduncle, and transforms into a trophont by sucking out the egg contents phagotrophically. After detaching from the host, the mature trophont settles down to become a palmelloid multiplication stage. By repeated binary fission, up to 16 or 32 gymnodinoid, colourless dinospores are formed inside a gelatinous envelope. The parasite retains its dinoflagellate (monadoid) nature throughout its whole vegetative life cycle. Even during the trophic and multiplication phase the species remains latently motile. Despite some resemblance to Dissodinium, there are sufficient reasons for the establishment of the new genus Syltodinium.

  20. 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.

  1. Rotifer communities of Deepor Beel, Assam, India: richness, abundance and ecology

    Directory of Open Access Journals (Sweden)

    B.K. Sharma

    2010-07-01

    Full Text Available Plankton samples collected from two sampling stations of Deepor Beel (a Ramsar site in Assam, northeastern India between November 2002 and October 2003, reveal 110 and 100 species of Rotifera, exhibit monthly richness ranging between 43-65 (56 plus or minus 6 and 38-60 (52 plus or minus 7 species and record 48.9-88.1 and 53.1-89.7% community similarities respectively. Rotifera (231 plus or minus 60 and 198 plus or minus 70 n/l comprise between 48.7 plus or minus 6.1 and 42.6 plus or minus 4.1% of zooplankton abundance at station I and II respectively, and follow trimodal annual patterns with peaks during winter. Brachionidae (90 plus or minus 43, 79 plus or minus 39 n/l > Lecanidae (45 plus or minus 13, 29 plus or minus 9 n/l form important quantitative components of Rotifera while Asplanchnidae > Synchaetidae > Trochosphaeridae are other notable families. Lecane > Brachionus > Keratella > Asplanchna > Platyias contribute notably to temporal variations of the rotifers. Asplanchna priodonta, Keratella cochlearis, Platyias quadricornis, Lecane leontina, Polyarthra vulgaris, Keratella tropica and Brachionus falcatus are important species. Analysis of variance comparisons indicate significant temporal variations in richness and abundance of Rotifera between stations and months. The rotifer communities exhibit higher species diversity, higher evenness, lower dominance and lack of quantitative dominance of any individual species. The present results show no definite periodicity of richness and abundance of this group, families or species. Individual abiotic factors register limited influence on richness and abundance while multiple regression exhibits higher cumulative influence of ten abiotic factors on these parameters at both sampling stations.

  2. A new method for analysis of the toxicity of organophosphorus pesticide, dimethoate on rotifer based on response surface methodology.

    Science.gov (United States)

    Guo, Ruixin; Ren, Xinkun; Ren, Hongqiang

    2012-10-30

    This study analyzed the toxicity of organophosphorus pesticide, dimethoate on freshwater rotifer Brachionus calyciflorus, using swimming angular and linear speed alteration as the sub-lethal endpoints. Response surface methodology (RSM) was applied in experimental design and data analysis to consider two related factors: toxic concentration, exposure time and their interaction. In general, inhibition effect of the pesticide on rotifer swimming was observed clearly at any given toxicant concentration. The highest inhibition rates in angular and linear speed were obtained in the shortest exposure time (11.36 min) and the highest dimethoate concentration (1.85 mg L(-1)). The RSM used for the analysis of treatment combinations showed that a cubic polynomial regression model was in good agreement with experimental results, with R(2)=0.992 and 0.9997, for swimming angular speed inhibition rate and linear speed inhibition rate (p<0.01, F-test, respectively). 3D reference surface plots and contour plots showed that the toxic effect was influenced not only by dimethoate concentration, but also by the exposure time. A time-step effect was observed clearly. Thus, the pesticide dimethoate had toxic stress on the swimming behavior of rotifers.

  3. Seasonal variations of rotifers from a high altitude urban shallow water body, La Cantera Oriente (Mexico City, Mexico)

    Science.gov (United States)

    Gutiérrez, Sergio González; Sarma, S. S. S.; Nandini, S.

    2016-12-01

    La Cantera Oriente is a shallow freshwater volcanic water body located at an altitude of 2 270 m above sea level in the Ecological Reserve of San Angel Pedregal of Mexico City (Mexico). In order to ensure the conservation of its biological heritage including zooplankton, the present work was undertaken to quantify the seasonal changes in the diversity and density of rotifers and the selected physico-chemical variables during 2013-2014. Qualitative analysis of the zooplankton samples yielded 68 rotifer species which represented 24 genera in 15 families. B rachionus calyciflorus Pallas, 1766, B. quadridentatus Hermann, 1783, Polyarthra vulgaris Carlin, 1943, Lecane closterocerca (Schmarda, 1859) and Keratella cochlearis (Gosse, 1851) were the most common species. Preston plots of species frequency-density revealed that as many as 30% of the rotifer taxa were dominant throughout the year. The species with high population densities were Brachionus quadridentatus, Lecane closterocerca, Keratella cochlearis, and Lepadella patella; their peak densities were 2 000, 1 000, 180 and 90 ind./L, all occurring in summer. Canonical correspondence analysis showed that Platyias quadricornis was related to the concentration of phosphates available in the environment and the conductivity, while B. quadridentatus was positively correlated with chlorophyll-a. The trophic status of the lake was eutrophic based on Chl-a content but oligotrophic with relation to the Brachionus:Trichocerca ratio.

  4. The impact of impoundment on the rotifer communities in two tropical floodplain environments: interannual pulse variations

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    CC. Bonecker

    Full Text Available Hydrological pulses are the main factor regulating the structure of biological communities in floodplains. Reservoirs above this ecosystem change the environment's dynamics and the community's biodiversity. This study evaluated the structure and stability of the rotifer community in response to changes in hydrological pulses after the Porto Primavera impoundment in the Upper Paraná River floodplain. The community was studied in a river and in a floodplain lake downstream of the dam over a four-year period before and after the impoundment. A decrease in species richness and abundance was observed soon after the impoundment, followed by an increase in these attributes and in specific diversity when the hydrometric level of the Paraná River rose and, consequently, increased the connectivity between the floodplain environments. Conochilus coenobasis, Filinia longiseta, Keratella cochlearis, Lecane proiecta and Polyarthra dolichoptera persisted throughout the study and contributed to community stability (the maintenance of rank in species abundance over time, which was high in the floodplain lake, mainly after the impoundment. Reductions in the frequency, intensity and amplitude of potamophase pulses after the impoundment led to the decrease in species richness and the increases in abundance, community stability, and species diversity, which determine community resilience.

  5. 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.

  6. Use of rotifers for the maintenance of monoalgal mass cultures of Spirulina

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, S.A.; Richmond, A.

    1987-01-01

    Zooplankton was successfully used for the biological control of unicellular algal contaminants in Spirulina mass cultures even under conditions adverse to the growth of Spirulina (maximal winter daily temperature of approximately 10 degrees C and very low bicarbonate concentration). Brachionus plicatilis (Rotifera) was the most successful species of zooplankton used. The interrelationships between Spirulina, green unicellular contaminant, and B. plicatilis were studied under various conditions. Two species of unicellular contaminant were used; Monoraphidium minutum was isolated from local cultures and Chlorella vulgaris, obtained from contaminated Spirulina cultures in Israel. The rotifer B. plicatilis successfully controlled the population size of both contaminants whether they were introduced in a single addition or as a daily dose. The biological control of the unicellular contaminants allows Spirulina to be cultured in a medium low in bicarbonate, thereby reducing the cost of the medium and increasing the quantity of CO2 that may be freely absorbed from the atmosphere at the optimal pH for Spirulina cultivation. (Refs. 9).

  7. Réflexions sur les rotifères en tant qu'indicateurs biologiques

    Directory of Open Access Journals (Sweden)

    POURRIOT R.

    1976-01-01

    Full Text Available Quelques espèces de Rotifères fournissent un bon exemple d'indicateurs écologiques pour un facteur limitant : Synchaeta lakowitziana, Conochitoides natans, Notholca spp (température, Brachionus plicatilis (salinité. Le système d'indexation des espèces à la qualité des eaux est discuté. Les espèces strictement édaphiques (non aquatiques, les espèces rares appartenant à des genres où la variabilité est grande et les espèces euryoecques, peu caractéristiques, devraient être exclues des listes d'indicateurs établies par SLADECEK (1973, car elles ne facilitent pas l'application de ce système. Il s'avère nécessaire d'améliorer le poids indicatif et la valeur de saprobité des espèces, de ne conserver que les plus caractéristiques par leur constance et leur fidélité. Il serait, de plus, intéressant de se référer à des index plus dynamiques que statiques.

  8. Estuarine trophic state assessment: New plankton index based on morphology of Keratella rotifers

    Science.gov (United States)

    Gopko, Mikhail; Telesh, Irena V.

    2013-09-01

    A new estuarine trophic state index - Keratella-index (KIN), based on the relative abundance of two common rotifer species, Keratella cochlearis and Keratella tecta, was developed and tested for the Neva Estuary (Gulf of Finland, Baltic Sea). The morphological trait variation of these plankton species and their responses to different trophic conditions were investigated at three nearshore stations. The morphological data confirm that K. cochlearis and K. tecta are likely to be two distinct species (not two morphs) at our study site. The mean lorica length of K. cochlearis and K. tecta differ significantly and there were no K. cochlearis individuals with extremely short spines (spine length significantly decreases with an increase in trophic state (R2 = 0.71; p spined K. cochlearis may be explained by the "rare-enemy effect". There was a significant correlation (R2 = 0.76; p < 0.001; R2 = 0.68; p < 0.01) between KIN and the common trophic state indices (TSI and QB/T, respectively). The KIN values indicated meso-eutrophic to strongly eutrophic conditions at different nearshore sampling sites and hence indicated that the Neva Estuary is eutrophic.

  9. 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

    of swimming velocity for a 10 degrees C temperature reduction) that is found to be largest for the brine shrimp Artemia salina nauplius (37 %) and the rotifer Brachionus plicatilis (26%), but negligible for the copepod Acartia tonsa (4%). We suggest that experimental data on change in swimming velocity (V......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......) due to change in kinematic viscosity (v) be correlated in terms of a power law, V proportional to v(-m). The present data on swimming velocity of copepods, brine shrimps and rotifers show values of exponent m approximate to 1.5 to 3, with a trend of decreasing values for increasing size of species...

  10. Optofluidic technology for monitoring rotifer Brachionus calyciflorus responses to regular light pulses

    Science.gov (United States)

    Cartlidge, Rhys; Campana, Olivia; Nugegoda, Dayanthi; Wlodkowic, Donald

    2016-12-01

    Behavioural alterations can occur as a result of a toxicant exposure at concentrations significantly lower than lethal effects that are commonly measured in acute toxicity testing. The use of alternating light and dark photoperiods to test phototactic responses of aquatic invertebrates in the presence of environmental contaminants provides an attractive analytical avenue. Quantification of phototactic responses represents a sublethal endpoint that can be employed as an early warning signal. Despite the benefits associated with the assessment of these endpoints, there is currently a lack of automated and miniaturized bioanalytical technologies to implement the development of toxicity testing with small aquatic species. In this study we present a proof-of-concept microfluidic Lab-on-a-Chip (LOC) platform for the assessment of rotifer swimming behavior in the presence of the toxicant copper sulfate. The device was designed to assess impact of toxicants at sub-lethal concentrations on freshwater crustacean Brachionus calyciflorus, testing behavioral endpoints such as animal swimming distance, speed and acceleration. The LOC device presented in this work enabled straightforward caging of microscopic crustaceans as well as non-invasive analysis of rapidly swimming animals in a focal plane of a video-microscopy system. The chip-based technology was fabricated using a new photolithography method that enabled formation of thick photoresist layers with minimal distortion. Photoresist molds were then employed for replica molding of LOC devices with poly(dimethylsiloxane) (PDMS) elastomer. The complete bioanalytical system consisted of: (i) microfluidic PDMS chip-based device; (ii) peristaltic microperfusion pumping manifold; (iii) miniaturized CMOS camera for video data acquisition; and (iv) video analysis software algorithms for quantification of changes in swimming behaviour of B. calyciflorus in response to reference toxicants.

  11. Rotifers from Thuy Tien lake and Nhu Y river in central Vietnam, with a description of Ploesoma asiaticum new species (Rotifera: Monogononta

    Directory of Open Access Journals (Sweden)

    Mau Trinh Dang

    2013-08-01

    Full Text Available We surveyed Thuy Tien lake and Nhu Y river, Thua Thien Hue province, Vietnam, for rotifers from March to August 2010, and additionally in February 2012 in Thuy Tien lake. A total of 98 species-level taxa are identified, belonging to 31 genera and 21 families. Of there, 52 are first records for Vietnam, Filinia minuta (Smirnov, 1928 is new to the Oriental region and Ploesoma asiaticum n. sp. is new to science. These results increase the rotifer record for Vietnam from 122 to 174 taxa. In addition to describing the new taxon, we provide comparative illustrations including trophi scanning electron microscopy photographs of Ploesoma hudsoni (Imhof 1891.

  12. 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.

  13. Metabolism of tryptophan, methionine and arginine in Diplodus sargus larvae fed rotifers: effect of amino acid supplementation.

    Science.gov (United States)

    Saavedra, M; Conceição, L E C; Pousão-Ferreira, P; Dinis, M T

    2008-06-01

    Dietary amino acids imbalances have been described when fish larvae are fed rotifers, what may lead to a reduction in growth rate. The tube-feeding technique can be used to assess the effect of free amino acid short term supplementation. In this study supplementation of tryptophan, methionine and arginine were tested in Diplodus sargus. Single crystalline (14)C amino acids as well as a mix of (14)C amino acids were used as tracers to compare results of individual amino acids metabolism with the average of all amino acids. The results show low absorption efficiencies for tryptophan (70%) and arginine (80%) and similar absorption for methionine (90%) when compared with the average of all amino acids. Supplementation of these amino acids seems to be viable but it did not result in higher retention compared to the amino acid mix. This means that tryptophan, methionine and arginine are probably not the limiting amino acid when Diplodus sargus larvae are fed rotifers. However, supplementation in these IAA may be required for their roles as precursors of important molecules other than proteins, in order to improve larval quality and/or performance.

  14. 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

  15. Use of Probiotic Bacillus spp. in Rotifer (Brachionus plicatilis) and Artemia (Artemia urmiana) Enrichment: Effects on Growth and Survival of Pacific White Shrimp, Litopenaeus vannamei, Larvae.

    Science.gov (United States)

    Jamali, Hadi; Imani, Ahmad; Abdollahi, Daruosh; Roozbehfar, Reza; Isari, Amin

    2015-06-01

    This study was to evaluate the effect of a preparation of Bacillus probiotic (Bacillus licheniformis and B. subtilis, 1:1) on growth and survival rate of Pacific white shrimp, Litopenaeus vannamei larvae. The larvae were fed on Artemia urmiana nauplii and Brachionus plicatilis enriched with the probiotic preparation at 1 × 10(6) CFU mL(-1) rate. The experimental setup was completely randomized design comprised of six treatments, namely solo Artemia nauplii (A) or rotifer (R), Artemia nauplii and rotifer without any enrichment (A + R), Artemia nauplii enrichment with probiotic bacilli (Bacillus licheniformis and B. subtilis) (A + B), rotifer enrichment with probiotic bacilli (R + B) and enriched Artemia nauplii and rotifer (A + R + B). All treatments were performed in triplicate. Chemical parameters of rearing water viz. pH, salinity and temperature were 7.5-8, 30-31 ppt and 31-32 °C, respectively. Photoperiod was 16L:8D. Shrimp larvae were fed Artemia nauplii and rotifers at 5-20 and 10-40 individuals per shrimp larvae four times a day, respectively. Growth and survival rate of larvae were determined at MII, MIII, PL1, PL4, PL7 and PL10 stages. Larvae in A + R + B treatment showed the highest total length (10.89 ± 0.51 mm), weight (674 ± 73 μg) and survival rate (65% ± 3.5). Lowest total length, weight and survival rate (7.96 ± 0.63 mm, 493 ± 52 μg and 24.5 ± 2.4%, respectively) were recorded in treatment B larvae. We concluded that Bacillus probiotic can improve growth and survival rate of Pacific white shrimp larvae without conceivably undesirable effects.

  16. 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.

  17. 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.

  18. Diversity characteristics of rotifer community at the Yangtze River estuary%长江口轮虫生物多样性特征分析

    Institute of Scientific and Technical Information of China (English)

    郭章伟; 孙薇; 袁林; 薛俊增; 周淑辉; 吴惠仙

    2014-01-01

    The distribution of runoff at the Yangtze River estuary is uneven , the runoff in the south branch is more than in the north , and the north salinity is greater than the south , so there is some difference in biological community between the south and north branches .We collected rotifers from five cross-sections in the south and north branches and investigated the rotifer biology. A total of9 species were i-dentified at the Taihaiqidu cross-section, belonging to 8 genera, 6 families, and the dominant species were Ascomorpha ecaudis, Tricho-cerca pusilla, Brachionus calyciflorus, et al.20 rotifer species were identified in the south branch , belonging to 12 genera, 6 families, and the dominant species of the south branch T.pusilla, L.patella, Lecane ungulata;11 rotifer species were identified in the south branch, belonging to 10 genera, 7 families, and the dominant species of the north branches were A.saltans, A.ecaudis, L.patella.We compared the component and structure of rotifer in the south and the north branches , and found that the species , density, diversity of the south was higher than those of the north , similarity of rotifers in the south and north branches was low .The different water environment of the two branches caused the difference of rotifer community structure , correlation between rotifers and water environment factors was ana-lyzed by relativity analysis among which salinity was the important factor , and difference of salinity determined the difference in species , density, and spatial-distribution of rotifer.%长江口径流在南北支分布不均导致北支盐度高于南支,因此南北支之间生物群落存在一定差异。2010年在长江口分支前的江段和南北支设置5个断面,开展轮虫生态研究。分支前的太海汽渡断面处共采集到轮虫9种,隶属6科8属,其中优势种为没尾无柄轮虫、暗小异尾轮虫、萼花臂尾轮虫等;长江口南支2个断面共采集轮虫20种,隶属于6

  19. Phaeobacter gallaeciensis reduces Vibrio anguillarum in cultures of microalgae and rotifers, and prevents vibriosis in cod larvae.

    Directory of Open Access Journals (Sweden)

    Paul W D'Alvise

    Full Text Available Phaeobacter gallaeciensis can antagonize fish-pathogenic bacteria in vitro, and the purpose of this study was to evaluate the organism as a probiont for marine fish larvae and their feed cultures. An in vivo mechanism of action of the antagonistic probiotic bacterium is suggested using a non-antagonistic mutant. P. gallaeciensis was readily established in axenic cultures of the two microalgae Tetraselmis suecica and Nannochloropsis oculata, and of the rotifer Brachionus plicatilis. P. gallaeciensis reached densities of 10(7 cfu/ml and did not adversely affect growth of algae or rotifers. Vibrio 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 is important for the antagonistic properties of P. gallaeciensis. The ability of P. gallaeciensis to protect fish larvae from vibriosis was determined in a bath challenge experiment using a multidish system with 1 larva per well. Unchallenged larvae reached 40% accumulated mortality which increased to 100% when infected with V. anguillarum. P. gallaeciensis reduced the mortality of challenged cod larvae (Gadus morhua to 10%, significantly below the levels of both the challenged and the unchallenged larvae. The TDA mutant reduced mortality of the cod larvae in some of the replicates, although to a much lesser extent than the wild type. It is concluded that P. gallaeciensis is a promising probiont in marine larviculture and that TDA production likely contributes to its probiotic effect.

  20. Rotifers enriched with a mixed algal diet promote survival, growth and development of barramundi larvae, Lates calcarifer (Bloch

    Directory of Open Access Journals (Sweden)

    Valentin Thépot

    2016-05-01

    Full Text Available Fulfilling the nutritional requirements of marine fish larvae, including barramundi (Lates calcarifer, remains a bottleneck for optimal commercial hatchery production. This study investigated the effect of mixed algal diets for the enrichment of rotifers on the survival, growth, development and stress resistance of barramundi larvae. Four groups of 2–13 days-post-hatch (dph barramundi larvae were fed rotifers enriched with either Nannochloropsis oculata, Chlorella vulgaris, or a blend of 50:50 or 75:25 of N. oculata to C. vulgaris (based on dry weight, DW, respectively. The highly unsaturated fatty acids (HUFAs docosahexaenoic acid (DHA, eicosapentaenoic acid (EPA and arachidonic acid (ARA were used as qualitative proxies of the feed. The barramundi larvae fed with the 50:50 diet outperformed all other treatments, with significantly greater larval length (P < 0.05, eye diameter (P < 0.05 and body depth (P < 0.05 at 10 dph, a trend conserved over the whole growth period. The barramundi larvae fed the 50:50 diet also achieved the highest flexion percentage at 10 dph (P < 0.05 and scored the highest survival past the stress test (85%; P < 0.05. The best performing treatment had the second highest level of DHA which suggests that while DHA is an important fatty acid for barramundi larvae it is likely its interaction with other EFA and monounsaturated fatty acid also plays a critical role in their development. Overall, blending microalgae species can enhance the balance of dietary fatty acid for barramundi larvae which in turn can lead to better growth, faster development and higher stress resistance when compared to monospecific microalgal diets.

  1. 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.

  2. 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

  3. Effect of n-3 HUFA levels in rotifers and Artemia on growth and survival of larval black sea bream ( Sparus macrocephalus)

    Science.gov (United States)

    Liu, Jingke; Li, Kuiran; Huang, Bingxin; Chen, Xiaolin

    2004-12-01

    Requirement for dietary n-3 HUFA (n-3 highly unsaturated fatty acid) for growth and survival of black sea bream ( Sparus macrocephalus) larvae was studied using rotifers and Artemia at various levels of n-3 HUFA. Five treatments with rotifers and Artemia differing in n-3 HUFA were prepared by enriching them with various oil emulsions. Results indicated that dietary n-3 HUFA significantly influence fish n-3 HUFA levels and are essential for growth and survival of black sea bream larvae. The results also indicated that the incorporation of n-3HUFA TG (triacylglycerols) into tissues of larval black sea bream was more effective from natural fish oil in comparison with n-3 HUFA fatty acid ethyl esters from ethyl-esterified oil.

  4. Effect of n-3 HUFA levels in rotifers and Artemia on growth and survival of larval black sea bream (Sparus macrocephalus)

    Institute of Scientific and Technical Information of China (English)

    LIU Jingke; LI Kuiran; HUANG Bingxin; CHEN Xiaolin

    2004-01-01

    Requirement for dietary n-3 HUFA (n-3 highly unsaturated fatty acid) for growth and survival of black sea bream (Sparus macrocephalus) larvae was studied using rotifers and Artemia at various levels of n-3 HUFA. Five treatments with rotifers and Artemia differing in n-3 HUFA were prepared by enriching them with various oil emulsions. Results indicated that dietary n-3 HUFA significantly influence fish n-3 HUFA levels and are essential for growth and survival of black sea bream larvae. The results also indicated that the incorporation of n-3HUFA TG (triacylglycerols) into tissues of larval black sea bream was more effective from natural fish oil in comparison with n-3 HUFA fatty acid ethyl esters from ethyl-esterified oil.

  5. 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.

  6. Widespread secondary contact and new glacial refugia in the halophilic rotifer Brachionus plicatilis in the Iberian Peninsula.

    Directory of Open Access Journals (Sweden)

    Sergi Campillo

    Full Text Available Small aquatic organisms harbour deep phylogeographic patterns and highly structured populations even at local scales. These patterns indicate restricted gene flow, despite these organisms' high dispersal abilities, and have been explained by a combination of (1 strong founder effects due to rapidly growing populations and very large population sizes, and (2 the development of diapausing egg banks and local adaptation, resulting in low effective gene flow, what is known as the Monopolization hypothesis. In this study, we build up on our understanding of the mitochondrial phylogeography of the halophilic rotifer Brachionus plicatilis in the Iberian Peninsula by both increasing the number of sampled ponds in areas where secondary contact is likely and doubling sample sizes. We analyzed partial mitochondrial sequences of 252 individuals. We found two deep mitochondrial DNA lineages differing in both their genetic diversity and the complexity of their phylogeographic structure. Our analyses suggest that several events of secondary contact between clades occurred after their expansion from glacial refugia. We found a pattern of isolation-by-distance, which we interpret as being the result of historical colonization events. We propose the existence of at least one glacial refugium in the SE of the Iberian Peninsula. Our findings challenge predictions of the Monopolization hypothesis, since coexistence (i.e., secondary contact of divergent lineages in some ponds in the Iberian Peninsula is common. Our results indicate that phylogeographic structures in small organisms can be very complex and that gene flow between diverse lineages after population establishment can indeed occur.

  7. Toxicity of TiO(2) nanoparticles to cladocerans, algae, rotifers and plants - effects of size and crystalline structure.

    Science.gov (United States)

    Clément, Laura; Hurel, Charlotte; Marmier, Nicolas

    2013-01-01

    With the rapid development of nanotechnology, there is an increasing risk of human and environmental exposure to nanotechnology-based materials. However, the data on the potential environmental effects of nanoparticles are scarce. The aim of this study is to assess the effect of particle size and crystal structure (anatase and rutile) of titanium dioxide on their toxicity. Thus, acute and chronic toxicity tests included a modified acute test (72 h) using daphnies and algae, rotifers and plants as model organisms. Gradient of toxicity varied with the tested biological organisms. Our results revealed that TiO(2) nanoparticles in anatase crystal structure are toxic in the entire set of tests conducted. However, at highconcentration, through their antimicrobial properties, they significantly promoted growth of roots. Because of its lipophilicity, the rutile crystalline structure of TiO(2) NPs form larger aggregates in aqueous medium; then they have less effect on biological organisms, and thus a lower toxicity than the anatase crystalline form of TiO(2). We also demonstrated that exposure duration, aggregation and concentrations are contributing factors in nanoparticles-mediated toxicity.

  8. 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.

  9. 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.

  10. Performances zootechniques comparées de Rotifères d'eau douce Brachionus calyciflorus et de nauplii d'Artemia salina chez les larves de la perche fluviatile Perca fluviatilis

    Directory of Open Access Journals (Sweden)

    Fiogbé, ED.

    2003-01-01

    Full Text Available Zootechnic Performences Compared between Freshwater Rotifer (Brachionus calyciflorus and Nauplii Artemia salina in River Perch Perca fluviatilis L. In able to improve survival rate and growth in perch Perca fluviatilis larvae which are very small at hatching stage, larvae are submitted two days after hatching to different live food: fresh water Rotifer Brachionus calyciflorus and nauplii of Artemia salina.Thus, to avoid the big mortality which occure because of manipulation of larvae, eggs in eye stage were shared in two duplicated groups and feeding of larvae started two days after hatching. Mortality was significant in the two groups from the day 7. However, at the end of the experiment, the group fed Rotifer at the begining of feeding, exhibited the best homogeneity, the best survival and the best food convertion ratio. So, this experiment has shown clearly that at hatching time, all perch larvae are not able to ingest nauplii Artemia. It is necessary to mix their starter food with Rotifer.

  11. 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...

  12. 轮虫与卤虫在营养价值等方面的比较%A comparison of rotifer and brine shrimp in nutrient value

    Institute of Scientific and Technical Information of China (English)

    田宝军; 李英文; 丁茜; 耿莉娜

    2007-01-01

    近些年来,随着水产养殖业的发展,轮虫(rotifer)和卤虫(Artemia)由于适口性好、蛋白含量高、对水质污染小等优点,已被广泛地应用于鱼、虾、蟹类的苗种生产,成为不可替代的生物饵料.本文对轮虫和卤虫的生物学特性、研究历史、营养价值、培养方式和营养强化等方面进行了比较性的综述,以便对轮虫与卤虫有进一步的了解.

  13. Ultraviolet B retards growth, induces oxidative stress, and modulates DNA repair-related gene and heat shock protein gene expression in the monogonont rotifer, Brachionus sp

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ryeo-Ok [Department of Chemistry, and Research Institute for Natural Sciences, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Rhee, Jae-Sung [Department of Molecular and Environmental Bioscience, Graduate School, Hanyang University, Seoul 133-791 (Korea, Republic of); Won, Eun-Ji [Department of Environmental Marine Sciences, College of Science and Technology, Hanyang University, Ansan 426-791 (Korea, Republic of); Lee, Kyun-Woo [Department of Chemistry, and Research Institute for Natural Sciences, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Kang, Chang-Mo [Laboratory of Cytogenetics and Tissue Regeneration, Korea Institute of Radiological and Medical Science, Seoul 139-709 (Korea, Republic of); Lee, Young-Mi [Department of Green Life Science, College of Convergence, Sangmyung University, Seoul 110-743 (Korea, Republic of); Lee, Jae-Seong, E-mail: jslee2@hanyang.ac.kr [Department of Chemistry, and Research Institute for Natural Sciences, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Molecular and Environmental Bioscience, Graduate School, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2011-02-15

    Ultraviolet B (UV-B) radiation causes direct cellular damage by breakage of DNA strands and oxidative stress induction in aquatic organisms. To understand the effect of UV-B radiation on the rotifer, Brachionus sp., several parameters including 24-h survival rate, population growth rate, and ROS level were measured after exposure to a wide range of UV-B doses. To check the expression of other important inducible genes such as replication protein A (RPA), DNA-dependent protein kinase (DNA-PK), Ku70, Ku80, and heat shock proteins (hsps) after UV-B radiation, we observed dose- and time-dependency at 2 kJ/m{sup 2}. We also examined 13 hsp genes for their roles in the UV-B damaged rotifer. Results showed that UV-B remarkably inhibited the population growth of Brachionus sp. The level of intracellular reactive oxygen species (ROS) was high at 2 kJ/m{sup 2}, suggesting that 2 kJ/m{sup 2} would already be toxic. This result was supported by other enzymatic activities, such as GSH levels, glutathione peroxidase, glutathione S-transferase, and glutathione reductase. For dose dependency, low doses of UV-B radiation (2, 4, and 6 kJ/m{sup 2}) significantly up-regulated the examined genes (e.g. RPA, DNA-PK, Ku70, and Ku80). For the time course study, RPA genes showed immediate up-regulation but returned to basal or lower expression levels compared to the control 3 h after UV-B exposure. The DNA-PK and Ku70/80 genes significantly increased, indicating that they may be involved in repairing processes against a low dose of UV-B exposure (2 kJ/m{sup 2}). At the basal level, the hsp90{alpha}1 gene showed the highest expression, and followed by hsp10, hsp30, hsp60, and hsc70, and hsp90{beta} in adults (w/o egg). In eggs, the hsp10 gene was expressed the highest, and followed by hsp30, hsp27, hsp90{alpha}1, and hsp60 genes. In real-time RT-PCR array on rotifer hsp genes, low doses of UV-B radiation (2 and 4 kJ/m{sup 2}) showed up-regulation of several hsp genes but most of the hsp

  14. 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

  15. 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.

  16. Seasonal dynamics of rotifer in a seasonal fishing moratorium lake - Lake Erhai, Yunnan Province, China%一座季节性休渔湖泊——洱海轮虫的季节动态特征

    Institute of Scientific and Technical Information of China (English)

    吴秋婷; 卫志宏; 朱江; 孟良; 吕兴菊; 赵萍萍; 韩博平; 林秋奇

    2012-01-01

    于2009年2-11月对洱海轮虫进行月际采样,分析洱海轮虫的多样性及其群落结构季节动态特征.洱海作为一个高原湖泊,其轮虫种类组成仍然呈现出热带-亚热带的主要特征.本研究共鉴定轮虫68种,多数种类为广布性或暖水性种类,隶属17科25属,异尾轮属、腔轮属和臂尾轮属是种类最多的三个属,占鉴定轮虫种类的37%.Lecane arcuata和Trichocera inermis为我国新记录种.轮虫生物量的季节分布呈“双峰型”,并分别出现在休渔期的中期和捕鱼期前期.在休渔期中期,轮虫主要以前节晶囊轮虫为优势种;在捕鱼期前期,轮虫先以螺形龟甲轮虫和广生多肢轮虫为优势,后以前节晶囊轮虫为优势.季节性休渔不仅使鱼类对轮虫的捕食压力出现季节性变化,而且还通过影响枝角类的群落结构改变枝角类对轮虫的竞争压力.在捕食和竞争的双重作用下,轮虫主要以大型杂食性种类——前节晶囊轮虫为优势种类,并呈现“双峰型”的季节分布模式.%Rotifers were sampled monthly from February to November in 2009 in Lake Erhai, Yunnan Province, China, in order to study their diversity and seasonal dynamics. Lake Erhai has a rotifer composition with tropical-subtropical characteristics: 68 species belonging to 25 genera of 17 families were identified, the majority of which were eurythermal or mesophilic. The genera of Tri-chocerca, Lecane and Brachionus were more abundant than others, accounting for 37% of the total community. Lecane arcuata and Trichocera inermis are new records in China. Biomass of the rotifer communities in Lake Erhai exhibited a bimodal seasonal cycle. An increase occurred during spring from low winter levels to an annual maximum in the mid fishing moratorium and a second increase in the early fishing season. In the mid fishing moratorium, the rotifer biomass was dominated by Asplanchna priodonla; while in the early fishing season, it was

  17. 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.

  18. 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.

  19. 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

  20. Morphological, morphometrical and molecular (CO1 and ITS) analysis of the rotifer Asplanchna brightwellii from selected freshwater bodies in Central Mexico.

    Science.gov (United States)

    Jiménez-Contreras, Jorge; Sarma, S S S; Calderón-Torres, Marissa; Nandini, S

    2013-11-01

    We evaluated different strains of the rotifer Asplanchna brightwellii collected from central Mexico using morphology, morphometry and molecular tools (CO1 and ITS). Three distinct clonal populations from each of the 3 regions (Mexico City, State of Mexico and State of Guerrero) were established under laboratory conditions. For a given waterbody, morphometric comparisons within the populations of A. brightwellii showed almost stable measurements of trophi and with no statistically significant differences among them (p > 0.05). However, asplanchnid body length and width as well as the cyst diameter varied significantly depending on the waterbody from which A. brightwellii was collected. The smallest adults (about 700 microm) were from Valerio Trujano lake (Guerrero State) samples while the largest were from Xochimilco lake. Similar tendencies were reflected in the diameter of resting eggs. In addition, morphologically the cysts of A. brightwellii from the three waterbodies showed slightly different pattern. The number of globular structures on the surface of cysts was smaller for Valerio Trujano strain, while these were larger and less numerous for both Xochimilco and Zumpango strains. The ITS region tree displayed two groups Xochimilco and Valerio Trujano -Zumpango, this analysis did not reflect the morphological grouping; on the contrary the CO1 gene tree separated the populations according to morphological clusters and location (Xochimilco, Valerio Trujano and Zumpango lakes). When the tree was built using the combination of both ITS and CO1 sequences, the phylogenetic relationships observed on CO1 gene were consistent; but showed differences with the relationships observed on ITS region tree (only two groups).

  1. 有机磷农药乐果对萼花臂尾轮虫游泳行为的影响%Behavioral Bioassay of Brachionus calyciflorus(rotifer)for Toxic Effect Assessment of Dimethoate

    Institute of Scientific and Technical Information of China (English)

    郭瑞昕; 王志良; 李国平; 陈建秋

    2013-01-01

    Toxic stress of dimethoate on freshwater rotifer Brachionus calyciflorus was evaluated,using swimming behaviors alteration as sub-lethal endpoint.Alteration of swimming behaviors was examined firstly when the rotifer was exposed under 5 dimethoate concentrations after 6h.The imbalance of swimming direction and inhibition on swimming speed of toxic stress was observed clearly.Alterations of swimming behavior under toxic stress were analyzed and classified into 3 aspects such as swimming direction change,swimming angle change and swimming speed change using principal component analysis.Toxicity test results indicated that the disruption of dimethoate on swimming behavior was high concentration dependent,which is the first study about the mode of dimethoate on different aspects of swimming behavior of rotifer.%以游泳行为变化情况为指标,考察了有机磷农药乐果对淡水种萼花臂尾轮虫(Brachionus calyciflorus)的毒性作用.测定了暴露在5个不同质量浓度乐果作用6小时后轮虫游泳行为的变化情况.可以观察到轮虫的游泳方向的平衡性被破坏,游泳角速度与线速度受到显著地抑制.采用主成分分析方法(PCA)分析了在乐果的作用下轮虫游泳行为的变化情况.结果显示游泳平衡性失衡,旋转角度变小,位移速率变慢.暴露6h后,0.2 mg/L质量浓度组轮虫游泳位移速率变慢最为明显,而在1.0,1.4和1.8 mg/L质量浓度组轮虫游泳平衡性失衡最为明显,结果表明轮虫游泳行为的变化情况与乐果的质量浓度高度相关.木研究方法与内容在国内外尚属首次报道.

  2. 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

  3. 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

  4. 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

  5. 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.

  6. 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

  7. Evidence of weak habitat specialisation in microscopic animals.

    Directory of Open Access Journals (Sweden)

    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.

  8. 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

  9. 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.

  10. 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.

  11. On the excretory system of the rotifer Habrotrocha rosa Donner.

    Science.gov (United States)

    Schramm, U

    1978-06-08

    The excretory system of Habrotrocha rosa consists of two protonephridia. From each of them seven tubules lead to a terminal organ, also called cyrtocyte. Its weir basket contains structures which resemble ciliary rootlets. The lumen of the excretory system is bordered by a syncytial layer of cytoplasm. Cells are only found in the upper region of the trunk, where the channel is twisted several times.

  12. Dicty_cDB: Contig-U11527-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available cDNA clone:dds41d02, 3' ... 220 2e-52 1 ( EU652316 ) Adineta vaga dihydrogenpyri...midine dehydrogenase g... 82 3e-45 14 ( EU850439 ) Adineta vaga dihydrogenpyrimidine dehydrogenase g... 88 1....0 (Q5R895) RecName: Full=Dihydropyrimidine dehydrogenase [NADP+]; ... 659 0.0 EU850439_1( EU850439 |pid:none) Adineta vaga dihydroge...npyrimidine ... 630 e-178 EU652316_1( EU652316 |pid:none) Adineta vaga dihydrogen...a fascicularis mRNA, clone Qn... 466 e-129 EU850441_1( EU850441 |pid:none) Philodina roseola dihydrogenpyrim

  13. TUFA DEPOSITION IN A KARST STREAM AS AN INDICATOR OF WATER QUALITY (PAPUK NATURE PARK, CROATIA

    Directory of Open Access Journals (Sweden)

    Maria Špoljar

    2011-12-01

    Full Text Available Tufa deposition and accompanying periphyton community were studied on artificial substrates, in karst Jankovac Stream (Papuk Nature Park, Croatia. Influence of environmental parameters on protozoans and metazoans in periphyton were assessed in two microhabitats, differed in flow velocity (fast 1.28  0.61 m s-1, medium 0.56  0.50 m s-1, and across different exposure period (one and two months. Measured environmental parameters indicated oligotrophic water condition. Samples collected in fast flow velocity reached significantly higher tufa deposition (0.26  0.04 mg cm-2 d-1 contrary to those in medium flow velocity (0.09  0.01 mg cm-2 d-1. Results of our study suggested that tufa deposition increased with temperature, flow velocity, amount of organic matter and algal biomass. In total, 26 taxa were identified on artificial substrate, among them 16 ciliate and 5 rotifer taxa. Most taxa recorded low abundance in periphyton, < 10 ind cm-2. Just few taxa achieved higher maximum abundances, i.e., ciliates: Chilodonella cucullulus (28 ind cm-2, Vorticella similis (68 ind cm-2 and rotifers: bdelloids (55 ind cm-2 and Dicranophorus forcipatus (64 ind cm-2. Periphyton community achieved statistically significant higher abundance in fast than in medium flow velocity microhabitats, with increasing effect through the longer exposure. We presume that oligotrophic conditions in karst running water facilitate tufa deposition. In this study we revealed microscopic freshwater organisms, often neglected in investigation, but very important in food webs as link to gastropods, crustaceans, insect larvae, juvenile and adult fish.

  14. Specificity of zooplankton distribution in meteorite crater ponds (Morasko, Poland

    Directory of Open Access Journals (Sweden)

    Kuczyńska-Kippen N.

    2013-07-01

    Full Text Available This study was conducted in order to define the most important factors responsible for the zooplankton community structure inhabiting four meteorite crater ponds, located near the city of Poznań (Poland. The functioning of the meteorite craters resembled that of other small water bodies, where seasonality, physical-chemical features (mainly chlorophyll a concentration, pH and conductivity or biological parameters (lack of fish structured zooplankton assemblages. Rotifer species richness and abundance were highest in the autumn (12 species and 5107 ind L-1 on average, while crustaceans prevailed in the summer (12 and 201, respectively. The dominating structure also depended on the season, with pelagic species occurring in the spring and autumn and mainly littoral species in the summer. Moreover, the temporary nature of the craters caused great differentiation in zooplankton among ponds and favoured organisms adapted to living in astatic reservoirs, e.g. bdelloids, Daphnia pulex or Macrocyclops viridis. The co-occurrence of a variable community of small crustaceans with large daphnids indicated the existence of an additional ecological niche – a thick layer of sediments. Despite the occurrence of adverse living conditions (oxygen deficiencies and periodic drying and the eutrophic character of the waters, these ponds were a source of many rare species (e.g. Keratella paludosa, even in the status of dominants. Protective measures (a nature reserve allowed the area of meteorite fall to remain quite natural, despite its location close to an urban area.

  15. Dicty_cDB: VHN326 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available |pid:none) Xenopus laevis MGC81821 protein, m... 291 3e-77 EU850439_1( EU850439 |pid:none) Adineta vaga dihydrogen...pyrimidine ... 290 6e-77 EU652316_1( EU652316 |pid:none) Adineta vaga dihydrogen

  16. Dicty_cDB: VHF880 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available [NADP+]; ... 214 1e-54 EU652316_1( EU652316 |pid:none) Adineta vaga dihydrogenpyrimidine ... 152 3e-36 EU85...0439_1( EU850439 |pid:none) Adineta vaga dihydrogenpyrimidine ... 152 3e-36 BC080003_1( BC080003 |pid:none)

  17. Dicty_cDB: Contig-U05702-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ) Pig DNA sequence from clone CH242-256J18 on chrom... 46 2.5 1 ( EU850439 ) Adineta vaga dihydrogenpyrimid...ine dehydrogenase g... 46 2.5 1 ( EU652316 ) Adineta vaga dihydrogenpyrimidine de

  18. Dicty_cDB: Contig-U13246-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 1 |pid:none) Philodina roseola dihydrogenpyrimi... 110 2e-23 EU652316_1( EU652316 |pid:none) Adineta vaga dihydrogen...pyrimidine ... 109 3e-23 EU850439_1( EU850439 |pid:none) Adineta vaga dihydrogenpyrimidine ... 109 3

  19. Dicty_cDB: SHJ464 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 2( AL356457 |pid:none) Human DNA sequence from clone RP11... 136 3e-31 EU652316_1( EU652316 |pid:none) Adineta vaga dihydrogen...pyrimidine ... 135 5e-31 EU850439_1( EU850439 |pid:none) Adineta vaga dihydrogenpyrimidine

  20. Dicty_cDB: CHP678 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available us laevis MGC81821 protein, m... 276 1e-72 EU850439_1( EU850439 |pid:none) Adineta vaga dihydrogenpyrimidine... ... 275 3e-72 EU652316_1( EU652316 |pid:none) Adineta vaga dihydrogenpyrimidine

  1. The use of protozoan, rotifers and nematodes as live food for shrimp raised in bft system

    OpenAIRE

    Loureiro, Cláudio Kinach; Junior, Wilson Francisco Britto Wasielesky; Abreu, Paulo Cesar Oliveira Vergne de

    2012-01-01

    O Meio de Cultivo de Protozoarios e Nematodeos – PNCM, possibilita a producao de microrganismos de forma barata para a utilizacao como alimento vivo em cultivos de camaroes marinhos. Ciliados produzidos no PNCM foram testados como alimento vivo para pos-larvas de camaroes em um experimento com quatro tratamentos: (BFT) somente bioflocos; (BFT 10) 10 mL de PNCM adicionado ao biofloco; (BFT 100) 100 mL de PNCM adicionado ao biofloco; BFT 1000) 1000 mL de PNCM adicionado ao biofloco. Os microrga...

  2. Faunal diversity of rotifers (Rotifera: Eurotatoria of Nokrek Biosphere Reserve, Meghalaya, India

    Directory of Open Access Journals (Sweden)

    B.K. Sharma

    2011-02-01

    Full Text Available Plankton samples collected from the Nokrek Biosphere Reserve of Meghalaya (Northeast India revealed 70 species of Rotifera belonging to 24 genera and 15 families. Eight species are new records from the state of Meghalaya. The Oriental Lecane blachei and the palaeotropical L. unguitata are biogeographically interesting elements. The Rotifera taxocoenosis of Nokrek Biosphere Reserve is characterized by a distinct richness of the tropic-centered genus Lecane, paucity of Brachionus species, greater diversity of littoral-periphytonic elements and a general tropical character with cosmopolitan (71.4% > tropicopolitan (17.1 % species.

  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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. Experiences with dormancy in tardigrades

    Directory of Open Access Journals (Sweden)

    Deborah BOSCHINI

    2004-09-01

    Full Text Available Tardigrades often colonise extreme habitats, in which they survive using both types of dormancy: quiescence and diapause. Together with nematodes and bdelloid rotifers, tardigrades are known to enter quiescence (with several forms of cryptobiosis: anhydrobiosis, cryobiosis, anoxybiosis, osmobiosis at any stage of their life cycle, from egg to adult. Entering anhydrobiosis, tardigrades contract their body into a so-called tun, loosing most of their free and bound water (>95%, synthesizing cell protectants (e.g., trehalose, glycerol, heat shock proteins and strongly reducing or suspending their metabolism. Our research on cryptobiosis focused on some ecological and evolutionary aspects. We evaluated: i the long-term anhydrobiotic survival by comparing quantitative data on recovery from naturally induced desiccation in several species of tardigrades; ii differences in survival patterns between species and populations by experimentally inducing anhydrobiosis and cryobiosis; iii phenotypic factors affecting anhydrobiotic survival. As regards diapause, we considered encystment and eggs. Encystment involves at least the synthesis of new cuticular structures. Morphological changes during cyst formation are more complex than those involved in tun formation. We analyzed more in detail encystment processes, comparing a semiterrestrial with a limnic species. Several inter-specific differences have been identified, other than the production of two types of cysts in the semiterrestrial species. Our analysis of life history traits of a laboratory reared strain of a soil tardigrade revealed a particular hatching phenology that involved the production of both subitaneous and resting eggs. The latter need a cue to hatch (dehydration followed by re-hydration. In addition, the evolutionary meaning of dormancy in tardigrades is discussed.

  9. 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.

  10. 广东省水库轮虫分布特征%Rotifer distribution in tropical reservoirs, Guangdong Province, China

    Institute of Scientific and Technical Information of China (English)

    林秋奇; 赵帅营; 韩博平

    2005-01-01

    在2000年调查了广东省18座水库的轮虫种类分布特征.在此基础上,于2001~2003年研究了滞留时间对飞来峡水库、流溪河水库和新丰江水库三座典型水库(平均滞留时间分别为14d、172d和644d)轮虫分布的影响.共检到轮虫101种,其中大多数种类来自臂尾轮科(Brachionidae)、腔轮科(Lecanidae)、异尾轮科(Trichcercidae)和疣毛轮科(Synchaetidae).常见属为龟甲轮属(Keratella)、臂尾轮属(Brachionus)、腔轮属(Lecane)、多肢轮属(Polyarthra)、异尾轮属(Trichocerca)、晶囊轮属(Asplanchna)、聚花轮属(Conochilus)和无柄轮属(Ascomorpha).从不同生活习性种类组成看,每次采样均以浮游种类为主.在直流型的飞来峡水库中,底栖和着生种类占种类数的41%;而在长滞留时间的新丰江水库中只占18%;中等滞留时间的流溪河水库则介于它们之间.从不同食性种类的丰度看,在新丰江水库和流溪河水库中,轮虫以滤食细小悬浮颗粒物的种类(螺形龟轮虫、独角聚花轮虫和广生多肢轮虫)为优势种;而在直流型的飞来峡水库中,以劫掠粒径较大食物的种类(疣毛轮虫等)为优势种.聚类分析表明,不同营养水平水库轮虫的组成并不是绝然不同的,而是随着营养水平的上升逐渐发生变化的.在营养水平较低水库中以广栖性的螺形龟甲轮虫为优势种,随着营养水平的上升,螺形龟甲轮虫优势度逐渐降低,而异尾轮虫或臂尾轮虫优势度逐渐上升,并在中富营养和富营养水库中成为优势种.

  11. 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...

  12. Influence of food-type on the population growth rate of the rotifier Brachionus calyciflorus in short-chronic assays

    NARCIS (Netherlands)

    Lürling, M.F.L.L.W.; Beekman, W.

    2006-01-01

    The type of food given during short chronic assays with the rotifer Brachionus calyciflorus might be one of the sources of variation in the reproductive rate of the rotifers. Ten green algal species were supplied as monospecific diets to examine variability in rotifer growth rate. In addition, rotif

  13. 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.

  14. Vibrio neptunius sp. nov., Vibrio brasiliensis sp. nov. and Vibrio xuii sp. nov., isolated from the marine aquaculture environment (bivalves, fish, rotifers and shrimps).

    Science.gov (United States)

    Thompson, F L; Li, Y; Gomez-Gil, B; Thompson, C C; Hoste, B; Vandemeulebroecke, K; Rupp, G S; Pereira, A; De Bem, M M; Sorgeloos, P; Swings, J

    2003-01-01

    The fluorescent amplified fragment length polymorphism (FAFLP) groups A5 (21 isolates), A8 (6 isolates) and A23 (3 isolates) distinguished in an earlier paper (Thompson et al., Syst Appl Microbiol 24, 520-538, 2001) were examined in more depth. These three groups were phylogenetically related to Vibrio tubiashii, but DNA-DNA hybridization experiments proved that the three AFLP groups are in fact novel species. Chemotaxonomic and phenotypic analyses further revealed several differences among the 30 isolates and known Vibrio species. It is proposed to accommodate these isolates in three novel species, namely Vibrio neptunius (type strain LMG 20536T; EMBL accession no. AJ316171; G +C content of the type strain 46.0 mol%), Vibrio brasiliensis (type strain LMG 20546T; EMBL accession no. AJ316172; G + C content of the type strain 45.9 mol%) and Vibrio xuii (type strain LMG 21346T; EMBL accession no. AJ316181; G +C content of the type strain 46.6 mol%). These species can be differentiated on the basis of phenotypic features, including fatty acid composition (particularly 14:0 iso, 14:0 iso 3-OH, 16:0 iso, 16:0, 17:0 and 17:1 omega8c), enzyme activities and utilization and fermentation of various carbon sources.

  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. 萼花臂尾轮虫多态性及形态型转化%Polymorphism and Morphotype Transformations in the Rotifer (Brachionus calyciflorus)

    Institute of Scientific and Technical Information of China (English)

    殷旭旺; 牛翠娟

    2007-01-01

    The relationship of three Brachionus calyciflorus morphotypes (two short-spined, single-spined and spineless ones) was studied in the laboratory. Newly hatched females of each morphotype were cultured individually in an inorganic or Asplanchna-conditioned mediums, and the morphotype of their offspring were checked at 200× magnification. Females of each morphotype, cultured in the inorganic medium, could produce offspring of these three morphotypes in a single generation. Females of all three morphotyes could respond to specific Asplanchna-substances when they were cultured in Asplanchna-conditioned medium. Moreover, we observed that these three morphotype females could coexist in the medium and had three types of egg-bearing females. Based on the above observations we suggest that B. calyciflorus was a morphotype complex and has three basic morphotypes.%在实验室条件下研究了萼花臂尾轮虫3种形态型(双短侧棘刺、单短侧棘刺和无侧棘刺)个体之间的关系. 从轮虫的培养水体中随机挑出若干3种形态型雌体的幼轮虫(龄长<24 h), 分别培养在正常培养液和晶囊轮虫培养液过滤液中. 将实验轮虫的后代(F1代)置于200倍显微镜下检查其个体的形态型. 实验结果表明, 在正常培养液中, 每种形态型轮虫个体都可以产生3种形态型的后代. 当培养在晶囊轮虫培养液过滤液中时, 这3种形态型轮虫的后代都具有2个显著增长的侧棘刺. 此外, 这3种形态型个体的轮虫能够共存于同一培养环境中, 而且每种形态型个体的轮虫都具有3种生殖类型的雌体. 由此推测萼花臂尾轮虫是一个由3种基础形态型个体组成的形态型轮虫复合体.

  17. 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.

  18. 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

  19. Dicty_cDB: Contig-U04034-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 25 EU850441_2( EU850441 |pid:none) Philodina roseola dihydrogenpyrimi... 118 2e-25 BT076529_1( BT076529 |pid...439 |pid:none) Adineta vaga dihydrogenpyrimidine ... 108 2e-22 AE017346_134( AE01

  20. Dicty_cDB: Contig-U13684-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available id:none) Homo sapiens MgcRacGAP mRNA for GT... 43 0.008 EU652316_3( EU652316 |pid:none) Adineta vaga dihyd...rogenpyrimidine ... 43 0.008 BC087167_1( BC087167 |pid:none) Rattus norvegicus Rho

  1. Dicty_cDB: VHH726 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ydrogenpyrimidine ... 291 4e-77 protein update 2009. 7.13 PSORT psg: 0.53 gvh: 0.43... 1e-79 (Q5R895) RecName: Full=Dihydropyrimidine dehydrogenase [NADP+]; ... 298 4e-79 EU850439_1( EU850439 |pid:none) Adineta vaga dih

  2. 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.

  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. 有机磷农药乐果对萼花臂尾轮虫生殖的影响%The effect of Dimethoate on the reproduction of freshwater rotifer

    Institute of Scientific and Technical Information of China (English)

    陈建秋; 王志良; 李国平; 郭瑞昕

    2012-01-01

      乐果是一种农业生产上广泛使用的有机磷农药,在对病虫害防治的同时也会对非靶生物带来一定的生态环境效应,轮虫是淡水生态系统中连接食物链的初级生产者与高级消费者的重要环节,考察乐果对轮虫的作用对于研究有机磷农药对水生生态系统的影响有着十分重要的意义.以常见淡水种萼花臂尾轮虫(Brachionus calyciflorus)为受试生物,考察了亚致死剂量乐果对淡水种萼花臂尾轮虫(Brachionus calyciflorus)生殖的影响,主要考察的实验指标有:轮虫总产卵量、总产后代量以及生活史各时期历时.结果表明乐果对轮虫的性成熟和生殖都有显著的影响.一方面,在任意的虫龄段1.0、1.4和1.8 mg·L-13个质量浓度乐果都显著地抑制了轮虫的生殖输出,总产卵量和总后代量有了明显地下降,3个质量浓度组轮虫总产卵量依次为(10.33±0.14)、(9.48±0.27)和(8.71±0.31)个,仅为对照组的78.69%、72.23%和66.34%,而总后代量依次为(7.64±0.12)、(6.85±0.25)和(5.69±0.13)个,仅为对照组的75.61%,67.83%和56.31%;另一方面乐果扰乱了轮虫正常的生活史周期,性成熟时间被推迟,1.0、1.4和1.8 mg·L-13个质量浓度组轮虫的幼年期依次为(24.28±1.17)、(30.31±0.32)和(28.50±0.40) h,占整个生活史的时间分配比例由16.99%(对照值)延长至21.23%、26.44%和27.16%,分别比对照组增加了13.78%、42.03%和33.55%.但轮虫的生殖期历时被缩短,3个质量浓度组轮虫的生殖期历时依次为(69.77±3.78)、(63.98±2.99)和(58.22±0.83) h,分别为对照组值的89.71%、82.27%和74.86%,占整个生活史的时间分配比例依次下降了1.02%、6.14%和6.45%.但低质量浓度的乐果(0.2和0.6 mg·L-1)对轮虫却有一定的刺激作用.0.2和0.6 mg·L-12个质量浓度组轮虫总产卵量分别比对照组提高了38.90%和22.99%,所产的后代总数分别比对照组提高了36.62%和34.22%,2个质量浓度的乐果显著地缩短了轮虫的幼年期(P<0.01)而延长了轮虫的生殖期历时(P<0.01).本研究结果表明有机磷农药乐果对轮虫有一定的生殖干扰作用,影响个体发育与性成熟时间、产卵量和产后代量.

  5. 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.

  6. 珠江广州河段轮虫群落结构的初步研究%PRIMARY STUDY ON ROTIFER COMMUNITY STRUCTURE IN THE GUANGZHOU SEGMENT OF THE RIVER PEARL

    Institute of Scientific and Technical Information of China (English)

    王庆; 杨宇峰

    2007-01-01

    2004年4月-2005年4月,对珠江广州河段轮虫群落结构特征进行了初步研究.经鉴定, 共发现轮虫65种(包括亚种),其中西氏三肢轮虫(Filinia novaezealandiae)、华美腔轮虫(Lecane elegans)为我国的新记录种.优势种为裂痕龟纹轮虫(Anuraeopsis fissa)、角突臂尾轮虫(Brachionus angularis)、尾突臂尾轮虫(Brachionus caudatus)、Filinia novaezealandiae、暗小异尾轮虫(Trichocerca pusilla)和微型多突轮虫(Liliferotrocha subtilis).调查发现径流量对轮虫密度有重要影响,轮虫的两次密度高峰分别出现在春末夏初和秋季.丰水期,轮虫密度较低;枯水期前期,轮虫密度较高;枯水期后期,轮虫密度较低.此外,轮虫种群还受到温度、盐度等因素的影响.研究结果表明轮虫在河流生态系统中具有重要作用.

  7. 青弋江芜湖段轮虫群落结构和物种多样性的初步研究%Community structure and species diversity of rotifers in the Wuhu section of the Qingyi River

    Institute of Scientific and Technical Information of China (English)

    温新利; 席贻龙; 张雷; 陆星家; 陈发扬

    2004-01-01

    2003年1-12月,对青弋江芜湖段轮虫群落结构和物种多样性的周年动态进行了初步研究,并分析了轮虫密度与水温、水体叶绿素a浓度和水流量等环境因子的关系,以便为我国轮虫区系以及河流中轮虫密度的季节变化规律的进一步研究提供基础资料.经鉴定,共发现轮虫104种,其中钳枝巨头轮虫(Cephalodella forceps)、长趾巨头轮虫(C. macrodactyla)、尾钩巨头轮虫(C. mucronata)、奇槌巨头轮虫(C. evabroedi)、突纹腔轮虫(Lecane hornemanni)、爱沙腔轮虫(L. elsa)、长趾似月腔轮虫(L. lunaris acus)和泛热三肢轮虫(Filinia camasecla)等8种轮虫为我国亚热带地区的新记录种;优势种为螺形龟甲轮虫(Keratella cochlearis)、广生多肢轮虫(Polyarthra vulgaris)和无尾无柄轮虫(Ascomorpha ecaudis).1-4月(汛期前),轮虫总密度与水温、叶绿素a浓度之间均呈现出显著的正相关关系(r=0.533, P<0.05; r=0.548, P<0.05);而在5-9月(汛期),轮虫总密度与水流量之间表现出显著的正相关关系(r=0.580, P<0.01);10-12月(汛期后),轮虫总密度和水温、叶绿素a浓度和水流量之间都表现出显著的正相关性(多元回归, R2=0.680, P<0.05);水流量对10-12月轮虫密度的影响最大(标准偏回归系数β1=0.312, β2 = 0.120, β3=0.593).轮虫的物种多样性指数分别与种类数和群落的物种均匀度之间呈现出显著的正相关关系(n=12, r1=0.600, P<0.05; n=12, r2=0.955, P<0.001),而与优势度之间却显示出显著的负相关关系(n=12, r=-0.942, P<0.001).

  8. Screening of Native Rotifers, Hydra, Planaria for Deriving Aquatic Life Criteria%水生生物水质基准研究中轮虫、水螅、涡虫类受试生物的筛选

    Institute of Scientific and Technical Information of China (English)

    郑欣; 闫振广; 刘征涛; 刘婷婷; 王晓南; 武江越; 王伟莉

    2015-01-01

    轮虫、水螅、涡虫是水生生态系统的重要生物类群.因其对水体污染较敏感,所以对水生生物基准研究有重要意义.依据我国生物区系资料及毒性数据丰度,筛选出8种代表性本土轮虫、水螅、涡虫类生物.参照美国水生生物基准技术指南,搜集、筛选了这8种代表性生物的急性毒性数据,通过数据分析,筛选出对各物种毒性最大的污染物,主要包括重金属、农药、有机锡化物、表面活性剂、吡啶胺类杀菌剂.分析污染物的物种敏感度分布,依据累积概率对代表性生物的物种敏感性进行分类,结果为:萼花臂尾轮虫(Brachionus calyciflorus)、绿水螅(Hydrav iridissima)、普通水螅(Hydra vulgaris)对重金属铜的累积概率为6.5%、85%和10.4%,普通水螅(Hydra vulgaris)对重金属汞的累积概率为6.3%;龟甲轮虫(Keratella cochlearis)和四齿腔轮虫(Lecane quadridentata)对五氯酚钠的累积概率为5.1%和7.6%;褐水螅(Hydrao ligactis)和绿水螅(Hydra viridissima)对三丁基氧化锡的累积概率为6.9%和13.8%,萼花臂尾轮虫(Brachionus calyciflorus)对氟啶胺的累积概率为6.7%,日本三角涡虫(Dugesia japonica)对四氯化碳、十二烷基苯磺酸钠的累积概率分别为6.7%和7.1%.上述结果表明:萼花臂尾轮虫、绿水螅对重金属铜敏感;普通水螅对重金属铜和汞敏感;龟甲轮虫和四齿腔轮虫对农药敏感;褐水螅和绿水螅对有机锡化物敏感;萼花臂尾轮虫对吡啶胺类杀菌剂敏感;日本三角涡虫对四氯化碳、表面活性剂敏感.这7种代表性生物可作为相关污染物的水生生物基准受试物种.

  9. 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/Harbing...PVVLGACCVLHNICELQNEEMDPE 441 >tr|B3G4K0|B3G4K0_9BILA PIF/Harbinger-like protein OS=Adineta vaga PE=4 SV=1 Le

  10. 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-

  11. 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.

  12. Rotaria of the Caribbean region

    NARCIS (Netherlands)

    Ridder, de Marg.

    1977-01-01

    1. In this paper, a study of Rotifers has been made of extensive material, collected in the Caribbean province by Dr. P. WAGENAAR HUMMELINCK, between 1930 and 1973. 2. 64 species of Rotifers have been found. For 19 of these, particulars are given on their morphology, ecology and biogeographical dist

  13. 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.

  14. 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.

  15. 酵母轮虫和以小球藻、螺旋藻强化的轮虫对3种仔鱼人工育苗效果的影响%Effects of rotifer enriched with alga Spirulina platensis intensively on artificial breeding of three fish species

    Institute of Scientific and Technical Information of China (English)

    杜涛; 黄洋; 罗杰

    2010-01-01

    分别采用酵母轮虫和以小球藻、螺旋藻粉强化培育5 h的酵母轮虫为饵料,投喂尖吻鲈Lates calcarifer、卵形鲳鲹Trachinotus ovatus、美国红鱼Sciaenops ocellatus仔鱼,比较其成活率.结果表明:投喂酵母轮虫仔鱼的成活率为0~4.3%,而投喂小球藻和螺旋藻粉强化的轮虫仔鱼成活率显著提高,分别为85.3%~97.3%和79.3%~94.3%.

  16. 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)

    OpenAIRE

    Luciana Almada Thomaz; Lídia Miyako Yoshii Oshiro; Andrea Cecchetto Bambozzi; José Teixeira de Seixas Filho; Leonardo Azevedo da Silva Rosadas

    2004-01-01

    Conduziu-se o presente trabalho com o objetivo de avaliar o efeito da substituição dos náuplios de Artemia sp. pelo rotífero enriquecido e congelado (Brachionus plicatilis, O.F. Müller, 1786) sobre a sobrevivência e peso seco das larvas. O experimento foi conduzido em blocos casualizados, sendo testados quatro regimes alimentares na larvicultura do camarão M. rosenbergii, com quatro repetições por tratamento. Nos regimes alimentares, realizaram-se substituições progressivas de náuplios de Art...

  17. 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.

  18. 米氏凯伦藻对褶皱臂尾轮虫、卤虫和黑褐新糠虾存活的影响%Effect of Karenia mikimotoi on the survival of rotifer Brachionus plicatilis, brine shrimp Artemia salina, and Neomysis awatschensis

    Institute of Scientific and Technical Information of China (English)

    孙科; 颜天; 周名江; 何建宗

    2010-01-01

    初步研究了一株米氏凯伦藻对褶皱臂尾轮虫(Brachionus plicatilis)、卤虫(Artemia salina)幼体和黑褐新糠虾(Neomysis awatschensis)的毒性效应和机制.研究发现米氏凯伦藻(Karenia mikimotoi)在较低密度下就能明显减少轮虫的种群数量, 24 h EC50仅为20个/mL左右; 该藻的各组分毒性比较结果显示, 只有藻液和细胞重悬液有这种毒害作用, 而去藻过滤液和藻细胞破碎液的影响不明显, 表明这种毒害作用可能是由于活的藻细胞引起的; 在米氏凯伦藻中卤虫和黑褐新糠虾的存活数量也明显下降.结果表明, 米氏凯伦藻赤潮可能通过直接影响存活从而对浮游动物产生影响.

  19. Live feed culture - Problems and perspectives

    Digital Repository Service at National Institute of Oceanography (India)

    Royan, J.P.

    The importance of live feed in aquaculture is stressed. Organisms currently cultured as live feed are microalgae, turbellarians, tanaidaceans, annelids, brine shrimps, fairy shrimps, rotifers, cladocerans and copepods. Their culture methods...

  20. 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.

  1. 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.

  2. Iodine nutrition and toxicity in Atlantic cod (Gadus morhua larvae

    Directory of Open Access Journals (Sweden)

    S Penglase

    2013-02-01

    Full Text Available Copepods as feed promote better growth and development in marine fish larvae than rotifers. However, unlike rotifers, copepods contain several minerals such as iodine (I, at potentially toxic levels. Iodine is an essential trace element and both under and over supply of I can inhibit the production of the I containing thyroid hormones. It is unknown whether marine fish larvae require copepod levels of I or if mechanisms are present that prevent I toxicity. In this study, larval Atlantic cod (Gadus morhua were fed rotifers enriched to intermediate (26 mg I kg-1 dry weight; MI group or copepod (129 mg I kg-1 DW; HI group I levels and compared to cod larvae fed control rotifers (0.6 mg I kg-1 DW. Larval I concentrations were increased by 3 (MI and 7 (HI fold compared to controls during the rotifer feeding period. No differences in growth were observed, but the HI diet increased thyroid follicle colloid to epithelium ratios, and affected the essential element concentrations of larvae compared to the other groups. The thyroid follicle morphology in the HI larvae is typical of colloid goitre, a condition resulting from excessive I intake, even though whole body I levels were below those found previously in copepod fed cod larvae. This is the first observation of dietary induced I toxicity in fish, and suggests I toxicity may be determined to a greater extent by bioavailability and nutrient interactions than by total body I concentrations in fish larvae. Rotifers with 0.6 mg I kg-1 DW appeared sufficient to prevent gross signs of I deficiency in cod larvae reared with continuous water exchange, while modelling of cod larvae versus rotifer I levels suggests that optimum I levels in rotifers for cod larvae is 3.5 mg I kg-1 DW.

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

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    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.

  4. Seasonal variations in zooplankton abundances in the Iturbide reservoir (Isidro Fabela, State of Mexico, Mexico).

    Science.gov (United States)

    Sarma, S S S; Osnaya-Espinosa, Lidia Rosario; Aguilar-Acosta, Claudia Romina; Nandini, S

    2011-07-01

    This studywas undertaken to quantify the seasonal variations of zooplankton (rotifers, cladocerans and copepods) and selected physico-chemical variables (temperature, pH, conductivity, Secchi disc transparency, dissolved oxygen, ammonia, nitrate and phosphate concentrations) in the Iturbide dam. Monthly zooplankton samples (50 l filtered through 50 microm mesh, in duplicates from each of the 4 stations) were collected from February 2008 to January 2009. Simultaneously physico-chemical variables were measured. The zooplankton samples were fixed in 4% formalin in the field. In general, the temperature ranged from 9 to 16 degrees C, rarely exceeding 20 degrees C. Secchi transparency was nearly 100% since the reservoir was shallow (Iturbide reservoir was dominated by rotifer species. We encountered in all, 55 taxa of rotifers, 9 cladocerans and 2 copepods. The rotifer families Trichocercidae and Notommatidae had the highest number of species (7 each) followed by Colurellidae and Lecanidae (6 and 5 species, respectively). Trichocerca elongata, Ascomorpha ovalis, K. americana, K. cochlearis, Lepadella patella and Pompholyx sulcata were the dominant rotifers during the study period. On an annual average, rotifer density ranged between 50-200 ind.(-1). Among crustaceans Chydorus brevilabris and Macrothrix triserialis were most abundant. The maximal density of these cladocerans was about 50 ind. l(-1). Copepods were much lower in numbers (Iturbide reservoir appeared to be mesotrophic.

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

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    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.

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

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    Chunyan Xu

    2015-11-01

    Full Text Available 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.

  7. 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.

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

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    Ignacio Alejandro Pérez-Legaspi

    2014-05-01

    Full Text Available 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.

  9. Diet affects the redox system in developing Atlantic cod (Gadus morhua larvae

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    Samuel Penglase

    2015-08-01

    Full Text Available The growth and development of marine fish larvae fed copepods is superior to those fed rotifers, but the underlying molecular reasons for this are unclear. In the following study we compared the effects of such diets on redox regulation pathways during development of Atlantic cod (Gadus morhua larvae. Cod larvae were fed a control diet of copepods or the typical rotifer/Artemia diet commonly used in commercial marine fish hatcheries, from first feeding until after metamorphosis. The oxidised and reduced glutathione levels, the redox potential, and the mRNA expression of 100 genes in redox system pathways were then compared between treatments during larval development. We found that rotifer/Artemia-fed cod larvae had lower levels of oxidised glutathione, a more reduced redox potential, and altered expression of approximately half of the redox system genes when compared to copepod-fed larvae. This rotifer/Artemia diet-induced differential regulation of the redox system was greatest during periods of suboptimal growth. Upregulation of the oxidative stress response transcription factor, nrf2, and NRF2 target genes in rotifer/Artemia fed larvae suggest this diet induced an NRF2-mediated oxidative stress response. Overall, the data demonstrate that nutritional intake plays a role in regulating the redox system in developing fish larvae. This may be a factor in dietary-induced differences observed in larval growth.

  10. Two-dimensional micro-beam imaging of trace elements in a single plankton measured by a synchrotron radiation X-ray fluorescence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ezoe, Masako; Sasaki, Miho; Hokura, Akiko; Nakai, Izumi [Tokyo Univ. of Science, Faculty of Science, Tokyo (Japan); Terada, Yasuko [Japan Synchrotron Radiation Research Inst., Mikazuki, Hyogo (Japan); Yoshinaga, Tatsuki; Tukamoto, Katsumi [Tokyo Univ., Ocean Research Inst., Tokyo (Japan); Hagiwara, Atsushi [Nagasaki Univ., Graduate School of Science and Technology, Bunkyou, Nagasaki (Japan)

    2002-10-01

    Two-dimensional imaging and a quantitative analysis of trace elements in rotifer, Brachionus plicatilis, belonging to zooplankton, were carried out by a synchrotron radiation X-ray fluorescence analysis (SR-XRF). The XRF imaging revealed that female rotifers accumulated Fe and Zn in the digestive organ and Fe, Zn, Cu, and Ca in the sexual organs, while the Mn level was high in the head. From a quantitative analysis by inductively coupled plasma mass spectrometry (ICP-MS), we found that rotifers eat the chlorella and accumulate the above elements in the body. The result of quantitative analyses of Mn, Cu, and Zn by SR-XRF in a single sample is in fair agreement with the average values determined by ICP-MS analyses, which were obtained by measuring a large number of rotifers, digested by nitric acid. The present study has demonstrated that SR-XRF is an effective tool for the trace element analysis of a single individual of rotifer. (author)

  11. 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.

  12. Recruitment from an egg bank into the plankton in Baisha Bay, a mariculture base in Southern China

    Science.gov (United States)

    Wang, Qing; Luan, Lei-Lei; Chen, Liang-Dong; Yuan, Dan-Ni; Liu, Sheng; Hwang, Jiang-Shiou; Yang, Yu-Feng

    2016-11-01

    The potential recruitment of resting eggs of calanoid copepods and rotifers to planktonic populations was investigated in the surface and sub-surface sediments of three mariculture zones: an integrated seaweed Gracilaria lemaneiformis and shellfish cultivation area (G), a fish cultivation area (F), and a shellfish cultivation area (S), as well as the sediments of a nearby control sea area (C) in a mariculture base in Southern China. The potential recruitment of copepod and rotifer eggs in the sediments of C and G was significantly higher than in F and S. Potential recruitment in the sub-surface sediments of F and S was not observed, suggesting that fish and shellfish mariculture may be responsible for this decrease. The hatching success of resting eggs of copepods and rotifers was affected by mariculture type, and that large-scale seaweed cultivation may offset the adverse effect of fish and shellfish cultivation on the resting eggs if integrated cultivation is adopted.

  13. PENYIMPANAN ROTIFERA INSTAN (Brachionus rotundiformis PADA SUHU YANG BERBEDA DENGAN PEMBERIAN PAKAN MIKROALGA KONSENTRAT

    Directory of Open Access Journals (Sweden)

    Erlania Erlania

    2016-11-01

    Full Text Available Keberhasilan kegiatan budidaya perikanan harus ditunjang dengan ketersediaan benih yang berkesinambungan. Oleh karena itu, diperlukan juga ketersediaan pakan alami larva berupa rotifera (Brachionus rotundiformis. Desain percobaan berupa rancangan faktorial dengan dua faktor dan lima ulangan diaplikasikan dalam penelitian ini. Sebagai perlakuan berupa suhu ruang penyimpanan (suhu kamar, suhu ruang AC, dan suhu refrigerator/lemari es dan pakan mikroalga konsentrat (monospesies dan multispesies. Bakteri probiotik juga digunakan sebagai pengontrol kualitas air. Spesies mikroalga yang digunakan adalah Nannochloropsis sp., Dunaliella sp., Isochrysis sp., dan Pavlova sp. Parameter yang diukur adalah kelimpahan rotifera dan parameter kualitas air media kultur (pH, salinitas, DO, dan NH3. Analisis data terdiri atas analisis regresi, analisis ragam, dan uji keparalelan. Hasil pengukuran parameter kualitas air selama penyimpanan menunjukkan kondisi media yang relatif stabil dan merupakan kisaran optimum bagi pertumbuhan B. rotundiformis. Kelimpahan maksimum tertinggi dari B. rotundiformis baik pada perlakuan pakan monospesies maupun multispesies alga adalah pada suhu kamar. Dari interaksi kedua perlakuan, diperoleh kelimpahan akhir tertinggi pada suhu ruang AC–pakan multispesies. Hal ini menunjukkan bahwa rotifera dapat disimpan lebih lama pada suhu ruang AC dengan pemberian pakan multispesies alga. The success of any aquaculture practices should be supported by sustainable supply of fish fry. Therefore, the availability of rotifers (Brachionus rotundiformis as natural feed for fish larvae is required. The research was arranged in factorial design with two treatments and five replications. Treatments consisted of different room storage temperatures (refrigerator, room temperature, and room with air conditioner/AC and microalgae concentrate added as rotifer feed (monospecies and multispecies algae. Probiotic bacteria was used to control water quality

  14. Food and feeding behaviour of Mozambique tilapia (Oreochromis mossambicus Peters from Borna Reservoir of Maharashtra, India

    Directory of Open Access Journals (Sweden)

    Vishwas balasaheb Sakhare

    2016-12-01

    Full Text Available The food analysis of 80 specimens of Oreochromis mossambicus collected from Borna Reservoir of Maharashtra, India revealed that the food of juveniles mainly consisted of rotifers (35%, followed by copepods (30%, Chlorophyceae (20%, Bacillariophyceae (10% and aquatic insects (5%. While the food items recorded in the gut of adults were Chlorophyceae (40%, followed by Bacillariophyceae (30%, rotifers (15%, copepods (10% and aquatic insects (5%. During present study it was found that the juveniles of O. mossamobicus mainly feed on zooplankton, and adults on phytoplankton. Intense feeding was noticed during summer season and juveniles were the active feeders.

  15. The role of light for fish-zooplankton-phytoplankton interactions during winter in shallow lakes - a climate change perspective

    DEFF Research Database (Denmark)

    Bramm, Mette Elisabeth; Lassen, Majbritt Kjeldahl; Liboriussen, Lone;

    2009-01-01

    1. Variations in the light regime can affect the availability and quality of food for zooplankton grazers as well as their exposure to fish predation. In northern lakes light is particularly low in winter and, with increasing warming, the northern limit of some present-day plankton communities may...... in the life history of copepods. The strength of the fish effect on zooplankton biomass diminished with declining light and the effect of light was strongest in the presence of fish. 4. When fish were present, reduced light led to a shift from rotifers to calanoid copepods in the clear lake and from rotifers...

  16. Telomere analysis of platyhelminths and acanthocephalans by FISH and Southern hybridization.

    Science.gov (United States)

    Bombarová, Marta; Vítková, Magda; Spakulová, Marta; Koubková, Bozena

    2009-11-01

    We examined the composition of telomeres in chromosomes of parasitic worms, representatives of the flatworm groups Monogenea and Cestoda (Platyhelminthes), and thorny-headed worms (Syndermata: Acanthocephala) by fluorescence in situ hybridization (FISH) with different telomeric repeat probes. Our results show that the (TTAGGG)n sequence, supposed to be the ancestral telomeric repeat motif of Metazoa, is conserved in Monogenea (Paradiplozoon homoion) and Cestoda (Caryophyllaeus laticeps, Caryophyllaeides fennica, and Nippotaenia mogurndae) but not in Acanthocephala (Pomphorhynchus laevis and Pomphorhynchus tereticollis). In the Pomphorhynchus species, no hybridization signals were obtained with the "nematode" (TTAGGC)n, "arthropod" (TTAGG)n, and bdelloid (TGTGGG)n telomeric probes using FISH with their chromosomes and Southern hybridization with P. laevis DNA. Therefore, we suggest that parasitic Acanthocephala have evolved yet unknown telomeric repeat motifs or different mechanisms of telomere maintenance.

  17. Diversity and distribution of Brachionidae (Rotifera in Thailand, with a key to the species

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    Sujeephon Athibai

    2013-08-01

    Full Text Available We investigated the diversity of brachionid rotifers in Thailand. Rotifers were collected from a wide range of habitat types (294 sites, 508 samples including canals, lakes, peat swamps, ponds, reservoirs, rice fields, rivers, swamps and temporary ponds from April 1998 to January 2004. Twenty-eight species including 11 infrasubspecific forms belonging to five genera were identified. The most frequently encountered species was Brachionus falcatus (50.7% of the sampling sites, followed by Keratella cochlearis (50%, B. angularis (49.7%, K. tropica (46.3% and B. forficula (45.9%. Less frequently encountered species were B. caudatus, B. durgae and B. urceolaris. These species were found in low abundances and only in a single site. Two sites in the Northeast – Nong Changpeuak and Bueng Srithat – recorded the greatest richness with 15 taxa, whereas no brachionid rotifers were found in 31 sites. On average, the species richness was five taxa per sampling site. A key to the genera and species of Thai brachionid rotifers is provided.

  18. An Updated Zooplankton Biodiversity of Turkish Inland Waters

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    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.

  19. 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...

  20. Indices of zooplankton community as valuable tools in assessing the trophic state and water quality of eutrophic lakes: long term study of Lake Võrtsjärv

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    Juta Haberman

    2014-03-01

    Full Text Available On the basis of long-term (1964-2011 research, we tested the hypothesis that the zooplankton community has a highly indicative value in assessing the ecosystem and trophic state of water bodies. Basing on the results of our study and taking into account relevant data from numerous zooplankton studies, we can conclude that the zooplankton measures deserving to be used as indicators in the monitoring of Lake Võrtsjärv (and other similar eutrophic water bodies could be the following: i indicatory species of eutrophic waters [Anuraeopsis fissa (Gosse, Keratella tecta (Gosse, Trichocerca rousseleti (Voigt, Chydorus sphaericus (O. F. Müller, Bosmina longirostris (O. F. Müller]; ii indicatory species of oligo-mesotrophic waters [Conochilus unicornis Rousselet, Kellicottia longispina (Kellicott, Ploesoma hudsoni (Imhof, Bosmina berolinensis Imhof, Eudiaptomus gracilis (Sars]; iii number and diversity of species; iv mean zooplankter weight, mean cladoceran weight, mean rotifer weight and mean copepod weight; v rotifer abundance; vi the share (% of rotifers in total zooplankton abundance; vii the ratio of abundance of large cladocerans to abundance of all cladocerans (NLargeClad/NClad; viii the ratio of calanoid copepod abundance to cyclopoid copepod abundance (NCal/NCycl; ix the ratio of crustacean abundance to rotifer abundance (NCrust/NRot . The results of our study show that several zooplankton parameters are among the biological quality elements (BQE deserving to be included in the Water Frame Directive system.

  1. Revised Protocol for Zooplankton Automated Analysis

    Science.gov (United States)

    2011-11-01

    classify the viability of organisms in the ≥ 50 µm size class (Lemieux, et al. 2007). This work focused on standard test organisms, including brine shrimp ... Artemia franciscana) and rotifers (Brachionus plicatilis and B. calyciflorus). Initial work was conducted with homogeneous monocultures with

  2. Protocol for Automated Zooplankton Analysis

    Science.gov (United States)

    2010-01-01

    the viability of organisms in the > 50 urn size class (Nelson, et al. 2007). This work focused on standard test organisms, including brine shrimp ... Artemia franciscana) and rotifers {Brachionus plicatilis and B. calyciflorus). Initial work was conducted with homogeneous monocultures with little to

  3. 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

  4. 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

  5. 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

  6. The Origin and Evolution of Baeyer-Villiger Monooxygenases (BVMOs: An Ancestral Family of Flavin Monooxygenases.

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    Maria Laura Mascotti

    Full Text Available The Baeyer-Villiger Monooxygenases (BVMOs are enzymes belonging to the "Class B" of flavin monooxygenases and are capable of performing exquisite selective oxidations. These enzymes have been studied from a biotechnological perspective, but their physiological substrates and functional roles are widely unknown. Here, we investigated the origin, taxonomic distribution and evolutionary history of the BVMO genes. By using in silico approaches, 98 BVMO encoding genes were detected in the three domains of life: Archaea, Bacteria and Eukarya. We found evidence for the presence of these genes in Metazoa (Hydra vulgaris, Oikopleura dioica and Adineta vaga and Haptophyta (Emiliania huxleyi for the first time. Furthermore, a search for other "Class B" monooxygenases (flavoprotein monooxygenases--FMOs--and N-hydroxylating monooxygenases--NMOs was conducted. These sequences were also found in the three domains of life. Phylogenetic analyses of all "Class B" monooxygenases revealed that NMOs and BVMOs are monophyletic, whereas FMOs form a paraphyletic group. Based on these results, we propose that BVMO genes were already present in the last universal common ancestor (LUCA and their current taxonomic distribution is the result of differential duplication and loss of paralogous genes.

  7. Zooplankton composition in five oxbow lakes from the Upper Juruá River, Acre State, Brazil

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    Maria José Alencar dos Santos

    2013-12-01

    Full Text Available This work was conducted in five oxbow lakes located between Cruzeiro do Sul and Rodrigues Alves counties (Acre State, Brazil, to provide additional information about the composition of zooplankton assemblages in the Upper Juruá River. Samples were collected from May 2009 to May 2010, and fixed with 4% formalina. The numeric density (ind.m -3 was obtained from subsequent sub-samples (1 mL. The study recorded 19 zooplankton families. Rotifers showed higher species richness (81 species, followed by cladocerans (3 species and various forms of copepods and other organisms. Higher zooplankton means of numeric density was found in Novo Lake, with rotifers (1879 ind.m -3, cladocerans (207 ind.m -3, copepods (870 ind.m -3 . Diversity and numeric density were similar to other Neotropical aquatic ecosystems.

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

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    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.

  9. On Pulchritia new genus, with a reappraisal of the genera of Trichotriidae (Rotifera, Monogononta

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    Yongting Luo

    2013-10-01

    Full Text Available During the study of rotifers collected in Eastern DR Congo, we rediscovered specimens that correspond to Monostyla dorsicornuta Van Oye, 1926. This species, which we redescribe, had not been seen since it’s summary description, and lacked type material. Our analysis reveals that the animal belongs to Trichotriidae rather than to Lecane (presently considered to include Monostyla or Lecanidae, but is nevertheless characterised by a foot structure that is remarkably convergent to that of Lecanidae, and different from all other genera of Trichotriidae.We conclude that the species and the closely related South American Macrochaetus kostei (José de Paggi, Branco & Kozlowsky-Suzuki, 2000 belong to a new genus of Trichotriidae; the two offer a rare example of African-South American vicariance in rotifers.We further provide emended diagnoses of the remaining genera of Trichotriidae, to conform these to the new information and to address some inconsistencies in these.

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

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    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.

  11. BMC Genomics

    OpenAIRE

    2009-01-01

    BACKGROUND Microscopic monogonont rotifers, including the euryhaline species Brachionus plicatilis, are typically found in water bodies where environmental factors restrict population growth to short periods lasting days or months. The survival of the population is ensured via the production of resting eggs that show a remarkable tolerance to unfavorable conditions and remain viable for decades. The aim of this study was to generate Expressed Sequence Tags (ESTs) for molecular characterisa...

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

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    JDN. Paranhos

    Full Text Available 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.

  13. Skeletal muscle growth dynamics and the influence of first-feeding diet in Atlantic cod larvae (Gadus morhua L.

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    Tu A. Vo

    2016-11-01

    Full Text Available Dynamics between hypertrophy (increase in cell size and hyperplasia (increase in cell numbers of white and red muscle in relation to body size [standard length (SL], and the influence of the first-feeding diets on muscle growth were investigated in Atlantic cod larvae (Gadus morhua. Cod larvae were fed copepod nauplii or rotifers of different nutritional qualities from 4 to 29 days post hatching (dph, Artemia nauplii from 20 to 40 dph and a formulated diet from 36 to 60 dph. The short period of feeding with cultivated copepod nauplii had a positive effect on both muscle hyperplasia and hypertrophy after the copepod/rotifer phase (19 dph, and a positive long term effect on muscle hypertrophy (60 dph. The different nutritional qualities of rotifers did not significantly affect muscle growth. We suggest here a model of the dynamics between hyperplasia and hypertrophy of red and white muscle fibre cells in relation to cod SL (4 to 30 mm, where the different red and white muscle growth phases clearly coincided with different metamorphosis stages in cod larvae. These shifts could be included as biomarkers for the different stages of development during metamorphosis. The main dietary muscle effect was that hypertrophic growth of red muscle fibres was stronger in cod larvae that were fed copepods than in larvae that were fed rotifers, both in relation to larval age and size. Red muscle fibres are directly involved in larval locomotory performance, but may also play an important role in the larval myogenesis. This can have a long term effect on growth potential and fish performance.

  14. PENGARUH INTENSITAS CAHAYA TERHADAP PEMANGSAAN LARVA IKAN CLOWN (Amphiprion ocellaris PADA AWAL PEMELIHARAAN

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    Ketut Maha Setiawati

    2016-11-01

    Full Text Available Penelitian pemangsaan larva ikan clown (Amphiprion ocellaris pada awal pemeliharaan dan umur sepuluh hari dilakukan menggunakan tangki serat kaca (fiberglass volume 200 L. Pakan zooplankton rotifera disediakan sejak telur menetas dengan kepadatan 5 ind./mL. Mulai D-8 zooplankton nauplii Artemia ditambahkan dengan kepadatan 1.700 ind./tangki. Pengambilan sampel dilakukan pada umur 1 hari dan sepuluh hari, masing-masing 10 ekor larva/sampling dengan interval waktu 3 jam. Larva diukur kemudian dibedah dan dianalisis jumlah pemangsaaannya dengan bantuan stereoscopic microscope. Hasil analisis menunjukkan peranan intensitas cahaya dalam aktivitas pemangsaannya sebesar 5 individu rotifera dengan intensitas cahaya 70 lux pada pagi hari, sedang pemangsaan tertinggi terjadi pada pukul 13.00—16.00 dengan pemangsaan 57 individu rotifera pada saat intensitas cahaya menurun. Spektrum warna cahaya diduga lebih berperanan pada kemampuan maksimal memangsa dari larva ikan laut. Observation on feeding activity of clown fish (A. ocellaris larvae have been conducted in 200 L. fiberglass tanks. Zooplankton rotifers were used as initial feed at a rate of 5 ind./mL. After eight days culture, nauplii Artemia were added at rate of 1,700 ind./ tank. Sampling was done on D-1 and D-10 at 10 individuals even sampling at three hours interval. The larvae were measured under a stereoscopic microscope, examining the digestion apparatus to count number of rotifers and nauplii Artemia as well. The result showed that the role of light intensity in feeding: 5 individual rotifer at 70 lux in early morning for D-1 larvae. The highest feeding occurred at 13.00-16.00 in the after noon at 57 individual rotifer when light intensity decreased. Color spectrum of light were predicted having more roles related to the maximum feeding rate  of clown fish larvae.

  15. Progress in live food production and use in fish and shellfish hatcheries

    OpenAIRE

    Sorgeloos, P

    1998-01-01

    Different species of microalgae, the rotifer, Brachionus spp., and the brine shrimp, Artemia spp., are essential live food in the farming of several species of molluscs (e.g. oyster, clam, scallop), crustaceans (e.g. marine shrimp, freshwater prawn, crabs) and fish (e.g. bass, bream, grouper, turbot, flounder, halibut, ayu). A brief overview is given of the latest developments in their production and use in industrial hatcheries.

  16. Chesapeake Bay Low Freshwater Inflow Study. Biota Assessment. Phase I. Appendices.

    Science.gov (United States)

    1980-08-01

    in lower Bay. 11. Macrofauna distribution with respect to sediment size. 12. Benthic infauna and sediment chemistry survey. 13. Plankton response to...transparent, gelatinous animal, roughly pear-shaped, with four oral lobes. Adults have no tentacles. The organism swims by means of its 8 rows of comb... planktonic rotifer of the family Brachionidae. Range: Brachionis calyciflorus is found worldwide in temperate fresh and oligohaline areas. In Chesapeake Bay

  17. Meiofaunal Richness in Highly Acidic Hot Springs in Unzen-Amakusa National Park, Japan, Including the First Rediscovery Attempt for Mesotardigrada.

    Science.gov (United States)

    Suzuki, Atsushi C; Kagoshima, Hiroshi; Chilton, Glen; Grothman, Gary T; Johansson, Carl; Tsujimoto, Megumu

    2017-02-01

    Extreme environments sometimes support surprisingly high meiofaunal diversity. We sampled runoff from the acidic hot springs of Unzen, Japan. This is the type locality of Thermozodium esakii Rahm, 1937, the only tardigrade in the class Mesotardigrada, which remains contentious in the absence of corroboration or supporting specimens. Our sampling revealed at least three species of arthropods, four rotifers, and five nematodes living in the hot (ca. 40°C) and acidic (ca. pH 2.5) water, but no tardigrades.

  18. 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. ...

  19. 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.

  20. Dredged Material Evaluations: Review of Zooplankton Toxicity Test Methods for Marine Water Quality Evaluations

    Science.gov (United States)

    2016-09-01

    are benthic). Only their short- duration larval stages are planktonic. Therefore, they are not holozooplankton (defined as animals that are planktonic...TOXCITY TESTING USING HOLOZOOPLANKTON: Testing using marine animals that are planktonic for all of their life cycle is needed to satisfy the... reproduction and can be tested for 48–hours in absence of food. Culturing and testing methods (48–hour) have also been published for rotifers

  1. 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.

  2. Microbial and nutritional aspects on the production of live feeds in a fish farming industry.

    Science.gov (United States)

    De Donno, A; Lugoli, F; Bagordo, F; Vilella, S; Campa, A; Grassi, T; Guido, M

    2010-03-01

    Aquaculture is an enterprise in constant development, in particular relating to its effect on the environment and also the quality of its products. It represents a valid alternative to traditional fishing, facing the increasing demand for fish products. To guarantee to the consumer a product of high nutritional, organoleptic and hygienic quality, it is fundamental to monitor every phase of the fish farming industry, isolating the potential risk points. For this reason there has been a rapid evolution of productive technique, particularly in the technology, artificial reproduction and feed sectors. The aim of this research has been the monitoring of the evolution of certain microbial and nutritional quality indexes (total microbial counts and lipid analysis on suspensions of Rotifers and Artemia, used as live feed) in the larval phase of the productive cycle of the farm raised fish, in an intensive system. The study has shown an increment in the total microbial counts in the fish farming industry within the production of Rotifers and Artemia, more evident in the suspensions of Rotifers. In addition the study has demonstrated that the maintenance phase, in the enrichment protocol, can reduce the EPA and DHA content. The results confirm the importance of microbial and nutritional control of the live feeds before they get supplied to fish larvae.

  3. Water quality and zooplankton composition in a receiving pond of the stormwater runoff from an urban catchment.

    Science.gov (United States)

    Jose de Paggi, Susana; Paggi, Juan; Collins, Pablo; Collins, Jorge; Graciela, Bernal

    2008-09-01

    Six storm periods were monitored from November 2002 to September 2005 at two stations of a receiving pond of the stormwater runoff from a small urban catchment of the city of Santa Fe, Argentina. Weekly samples were taken before and after rain events under different conditions of temperature, pluvial precipitation, and duration of the previous dry period. A sampling station was established at the outlet of the catchment (S1) and another one near the outlet of the receiving pond (S2). Both stations differed significantly in their dissolved oxygen (DO) concentration, temperature, transparency, and zooplankton composition. The concentrations of nutrients and BOD5 values indicated permanently eutrophic condition at both stations. After rainstorms, the concentrations of lead, zinc and suspended solids showed a marked increase. The zooplankton composition at S1 was characterized by the abundance of protozoans (Dexiostoma campylum (Stokes) Didinium nasutum Muller, Plagyopila cf nasuta, and Bdelloidea rotifers (Philodina sp and Rotaria sp), while Monogononta rotifers and small cladocerans were dominant at S2. The most abundant species were the rotifers Platyias quadricornis (Ehrenberg), Mytilina ventralis (Ehrenberg) and Lepadella ovalis (Muller), and the cladoceran Chydorus pubescens Sars.

  4. Life strategy and grazing intensity responses of Brachionus calyciflorus fed on different concentrations of microcystin-producing and microcystin-free Microcystis aeruginosa

    Science.gov (United States)

    Liang, Ye; Ouyang, Kai; Chen, Xinglan; Su, Yuqi; Yang, Jiaxin

    2017-01-01

    The occurrence of Microcystis blooms is a worldwide concern due to the numerous adverse effects on zooplankton. We therefore hypothesized that the cyanobacterium Microcystis aeruginosa is harmful to rotifer growth. Population and individual experiments were conducted with the same proportional volumes of Chlorella and Microcystis for given food densities. Life-table parameters, life-history traits, and the grazing intensity of Brachionus calyciflorus were evaluated after they had fed on microcystin-producing and microcystin-free Microcystis, both alone and combined with an edible alga (Chlorella pyrenoidosa), at concentrations of 1 × 105, 1 × 106, and 1 × 107 cells mL−1. The results showed that the interactive effects of food density and type appeared to be synergistic on generation time (T), net reproduction rate (R0), body length, swimming speed, and reproduction time. In contrast, these effects appeared to be antagonistic on intrinsic growth rate (r), finite rate of increase (λ), time to first brood, post-reproductive time and total offspring per female. The grazing rate of rotifers decreased with grazing time. Although the toxins released after grazing on M. aeruginosa had negative effects on rotifer growth and reproduction, B. calyciflorus changed its life strategy and grazing intensity in response to eutrophic conditions. PMID:28230067

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

    Directory of Open Access Journals (Sweden)

    T. A. S. V. Paes

    Full Text Available Abstract 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.

  6. 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.

  7. Rotifera diversity of a floodplain lake of the Brahmaputra river basin of lower Assam, Northeast India

    Directory of Open Access Journals (Sweden)

    Sharma, B.K.

    2012-07-01

    Full Text Available This study analyzed diversity and ecology of planktonic Rotifera of Ghorajan beel, a floodplain lake of the Brahmaputrariver basin of lower Assam region of Northeast India. Plankton samples collected (January–December, 2010 fromlittoral (station 1 and semi-limnetic regions (station 2 of this tropical wetland revealed a fairly rich rotifer fauna (84 and 80species with distinct variations (range, average ± SD in monthly richness (35–55, 46±6 and 24–54, 36±5 species andcommunity similarities (46.6–80.4 and 37.0–95.9 % at both sampling stations. The richness followed unclear annual patterns.The rotifers mainly contributed (53.3±5.1 and 55.6± 3.6 % to zooplankton abundance variations and showed high abundancefrom June through November at both stations. Brachionidae > Lecanidae exhibited high number of individuals; Asplanchnidaeand Flosculariidae were also quantitatively important families; specifically, Asplanchna priodonta, Sinantherina socialis, Brachionusfalcatus and Lecane bulla were important species for their abundance. Single abiotic factors exerted a more limited influence on richness than on abundance. Canonical correspondence analysis (CCA explained 55.6 % and 59.5 % cumulative variance of the rotifer assemblages along axis 1 and 2, respectively; the CCA indicated the importance of transparency and rainfall at station 1, and of transparency, dissolved oxygen and rainfall at station 2. Consequently, the littoral and semi-limnetic stations are characterized by micro-environmental differences.

  8. A comparison of standard acute toxicity tests with rapid-screening toxicity tests

    Energy Technology Data Exchange (ETDEWEB)

    Toussaint, M.W. [Geo-Centers, Inc., Fort Washington, MD (United States); Shedd, T.R. [Army Biomedical Research and Development Lab., Frederick, MD (United States); Schalie, W.H. van der [Environmental Protection Agency, Washington, DC (United States); Leather, G.R. [Hood Coll., Frederick, MD (United States). Dept. of Biology

    1995-05-01

    This study compared the relative sensitivity of five inexpensive, rapid toxicity tests to the sensitivity of five standard aquatic acute toxicity tests through literature review and testing. The rapid toxicity tests utilized organisms that require little culturing or handling prior to testing: a freshwater rotifer (Branchionus calyciflorus); brine shrimp (Artemia salina); lettuce (Lactuca sativa); and two microbial tests (Photobacterium phosphoreum--Microtox{reg_sign} test, and a mixture of bacterial species--the Polytox{reg_sign} test). Standard acute toxicity test species included water fleas (Daphnia magna and Ceriodaphnia dubia), green algae (Selenastrum capricornutum), fathead minnows (Pimephales promelas), and mysid shrimp (Mysidopsis bahia). Sensitivity comparisons between rapid and standard acute toxicity tests were based on LC50/EC50 data from 11 test chemicals. Individually, the lettuce and rotifer tests ranked most similar in sensitivity to the standard tests, while Microtox fell just outside the range of sensitivities represented by the group of standard acute toxicity tests. The brine shrimp and Polytox tests were one or more orders of magnitude different from the standard acute toxicity tests for most compounds. The lettuce, rotifer, and Microtox tests could be used as a battery for preliminary toxicity screening of chemicals. Further evaluation of complex real-world environmental samples is recommended.

  9. Comparison of standard acute toxicity tests with rapid-screening toxicity tests

    Energy Technology Data Exchange (ETDEWEB)

    Toussaint, M.W.; Shedd, T.R.; VanDerSchal, W.H.; Leather, G.R.

    1995-10-01

    This study compared the relative sensitivity of five inexpensive, rapid toxicity tests to the sensitivity of five standard aquatic acute toxicity tests through literature review and testing. The rapid toxicity tests utilized organisms that require little culturing or handling prior to testing: a freshwater rotifer (Branchionus ccalyciflorus); brine shrimp (Artemia salina); lettuce (Lactuca sativa); and two microbial tests (Photo bacterium phosphoreum - Microtox test, and a mixture of bacterial species - the polytox test). Standard acute toxicity test species included water fleas (Daphnia magna and Ceriadaphnta dubia), green algae (Setenastrum capricarnutum), fathead minnows (Pimephalespromelas), and mysid shrimp (Mysidopsis bahia). Sensitivity comparisons between rapid and standard acute toxicity tests were based on LC5O/EC50 data from 11 test chemicals. Individually, the lettuce and rotifer tests ranked most similar in sensitivity to the standard tests, while Microtox fell just outside the range of sensitivities represented by the group of standard acute toxicity tests. The brine shrimp and Polytox tests were one or more orders of magnitude different from the standard acute toxicity tests for most compounds. The lettuce, rotifer, and Microtox tests could be used as a battery for preliminary toxicity screening of chemicals. Further evaluation of complex real-world environmental samples is recommended.

  10. 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.

  11. Repurposing FDA-approved drugs for anti-aging therapies.

    Science.gov (United States)

    Snell, Terry W; Johnston, Rachel K; Srinivasan, Bharath; Zhou, Hongyi; Gao, Mu; Skolnick, Jeffrey

    2016-11-01

    There is great interest in drugs that are capable of modulating multiple aging pathways, thereby delaying the onset and progression of aging. Effective strategies for drug development include the repurposing of existing drugs already approved by the FDA for human therapy. FDA approved drugs have known mechanisms of action and have been thoroughly screened for safety. Although there has been extensive scientific activity in repurposing drugs for disease therapy, there has been little testing of these drugs for their effects on aging. The pool of FDA approved drugs therefore represents a large reservoir of drug candidates with substantial potential for anti-aging therapy. In this paper we employ FINDSITE(comb), a powerful ligand homology modeling program, to identify binding partners for proteins produced by temperature sensing genes that have been implicated in aging. This list of drugs with potential to modulate aging rates was then tested experimentally for lifespan and healthspan extension using a small invertebrate model. Three protein targets of the rotifer Brachionus manjavacas corresponding to products of the transient receptor potential gene 7, ribosomal protein S6 polypeptide 2 gene, or forkhead box C gene, were screened against a compound library consisting of DrugBank drugs including 1347 FDA approved, non-nutraceutical molecules. Twenty nine drugs ranked in the top 1 % for binding to each target were subsequently included in our experimental analysis. Continuous exposure of rotifers to 1 µM naproxen significantly extended rotifer mean lifespan by 14 %. We used three endpoints to estimate rotifer health: swimming speed (mobility proxy), reproduction (overall vitality), and mitochondria activity (cellular senescence proxy). The natural decline in swimming speed with aging was more gradual when rotifers were exposed to three drugs, so that on day 6, mean swimming speed of females was 1.19 mm/s for naproxen (P = 0.038), 1.20 for fludarabine (P = 0

  12. PEMELIHARAAN LARVA IKAN KLOWN (Amphiprion percula DENGAN PAKAN ALAMI YANG BERBEDA

    Directory of Open Access Journals (Sweden)

    Ketut Maha Setiawati

    2016-11-01

    Full Text Available Nilai jual ikan hias klown sangat tergantung dari kecerahan dan keunikan warna yang dimilikinya, namun ikan hias produk hatcheri masih belum sebaik hasil tangkapan alam. Pengkayaan dengan bahan komersial dan Nannochloropsis sp. pada rotifer dan Artemia sebagai pakan alami tidak mampu meningkatkan kecerahan warna benih ikan. Oleh sebab itu, diperlukan pakan alami lain yang mampu meningkatkan kecerahan warna. Penelitian ini bertujuan untuk mengetahui pengaruh pemberian rotifer dan copepod terhadap performan warna benih ikan klown, serta pertumbuhan dan sintasan yang dihasilkan. Penelitian dilakukan dengan menggunakan wadah bak fiber volume 200 L yang diisi air laut sebanyak 150 L. Telur ikan klown yang telah berumur enam hari ditebar sebanyak 200 butir/bak. Perlakuan berupa pemberian pakan alami: (A rotifer dan (B rotifer + copepod yang masing-masing mempunyai lima ulangan. Pemberian pakan perlakuan dilakukan sampai larva berumur 30 hari. Selain pakan perlakuan, mulai hari ke-20 juga ditambahkan pakan buatan berupa pakan mikro pada semua larva. Hasil penelitian menunjukkan bahwa, tambahan copepod sebagai pakan alami pada pemeliharaan larva ikan klown dapat meningkatkan kecerahan warna. Selain itu, panjang total dan bobot badan larva pada hari ke-20 untuk perlakuan B adalah masingmasing 10,44 ± 0,24 mm dan 15,2 ± 0,5 mg lebih baik daripada perlakuan A yaitu 9,15 ± 1,27 mm dan 9,2 ± 0,1 mg. Demikian pula vitalitas benih yang dihasilkan, menunjukkan bahwa ikan pada perlakuan B lebih kuat dibandingkan perlakuan A. Benih ikan pada perlakuan B tahan selama 231,6 detik dalam air tawar sedangkan pada perlakuan A hanya selama 39,8 detik. Price of ornamental fish highly depends on the brightness and unique appearance of its color. While of ornamental fish bred in hatcheries are less attractive in appearance compared to the wild ones. Enrichment of live feed i.e rotifer and Artemia using commercial enrichment and Nannochloropsis sp. was not able to

  13. [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.

  14. Seasonal changes in the invertebrate community of granular activated carbon filters and control technologies.

    Science.gov (United States)

    Wang, Qing; You, Wei; Li, Xiaowei; Yang, Yufeng; Liu, Lijun

    2014-03-15

    Invertebrate colonization of granular activated carbon (GAC) filters in the waterworks is one of the most frequently occurring and least studied biological problems of water processing in China. A survey of invertebrate colonization of GAC filters was carried out weekly from October 2010 to December 2011 at a reservoir water treatment works in South China. Twenty-six kinds of invertebrates were observed. The abundance was as high as 5600ind.m(-3) with a mean of 860ind.m(-3). Large variations in abundance were observed among different seasons and before and after GAC filtration. The dominant organisms were rotifers and copepods. The average invertebrate abundance in the filtrate was 12-18.7 times of that in the pre-filtered water. Results showed that the GAC filters were colonized by invertebrates which may lead to a higher output of organisms in the filtrate than in the pre-filtered water. The invertebrate abundance in the GAC filters was statistically correlated with the water temperature. Seasonal patterns were observed. The invertebrate abundance grew faster in the spring and summer. Copepods were dominant in the summer while rotifers dominated in all other seasons of the year. There was a transition of small invertebrates (rotifers) gradually being substituted by larger invertebrates (copepods) from spring to summer. Control measures such as backwashing with chloric water, drying filter beds and soaking with saliferous water were implemented in the waterworks to reduce invertebrate abundances in the GAC filters. The results showed that soaking with saliferous water (99%, reduction in percent) was best but drying the filter beds (84%) was more economical. Soaking filter beds with 20g/L saliferous water for one day can be implemented in case of emergency. In order to keep invertebrate abundance in the acceptable range, some of these measures should be adopted.

  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. Evaluation of nutritive value of protein source in diets of larval mud crab, Scylla serrata%锯缘青蟹幼体饵料蛋白质的营养价值评价

    Institute of Scientific and Technical Information of China (English)

    翁幼竹; 李少菁; 王桂忠

    2001-01-01

    This paper analysed the amino acid composition in larval mud crab, Scylla serrata,from zoea I to megalopa, and their diets, rotifer and nauplii of Artemia. An essential amino acid index (EAAI) was employed to evaluate the nutritive value of the protein source in diets. The results indicated that amino acid composition of different larval stages was basically stable, and had no obvious correlation with the change of diets. The values of EAAI in rotifer and nauplii of Artemia were all above 90 for different larval stages of Scylla serrata. It was suggested that rotifer and nauplii of Artemia may satisfy the nutritive requirement of larval Scylla serrata for amino acids in diet protein.%本文分析测定了锯缘青蟹幼体从刚孵化至大眼幼体各发育阶段及其饵料轮虫和卤虫无节幼体的氨基酸组成,并使用必需氨基酸指数(EAAI)来评价饵料蛋白质的质量.结果表明,青蟹各期幼体的氨基酸组成基本趋于一致,且与饵料转换不存在明显的相关性.对于各期幼体,饵料轮虫和卤虫无节幼体的必需氨基酸指数均大于90,可以认为,轮虫和卤虫无节幼体能够满足锯缘青蟹幼体对饵料中必需氨基酸的营养需求.

  17. 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.

  18. 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.

  19. 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...

  20. 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

  1. 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.

  2. Experimental evidence of the effect of nutrient enrichment on the zooplankton in a Brazilian coastal lagoon

    Directory of Open Access Journals (Sweden)

    B. KOZLOWSKY-SUZUKI

    Full Text Available Non-treated sewage disposal is one of the main impacts to which Imboassica Lagoon has been subjected. The aim of this study was to evaluate the effect of a potential increase in the artificial enrichment on the environmental conditions and zooplankton of this system. To this end, an experimental study was conducted in mesocosms where nutrients were added daily. Bacterial numbers, chlorophyll-a, and picoplanktonic cyanobacteria densities showed an increase with the availability of nutrients. Bacterio- and phytoplankton seemed to be regulated by the rotifers Brachionus rotundiformis and Hexarthra brandorffi.

  3. Evolution of the AKH/corazonin/ACP/GnRH receptor superfamily and their ligands in the Protostomia

    DEFF Research Database (Denmark)

    Hauser, Frank; Grimmelikhuijzen, Cornelis

    2014-01-01

    In this review we trace the evolutionary connections between GnRH receptors from vertebrates and the receptors for adipokinetic hormone (AKH), AKH/corazonin-related peptide (ACP), and corazonin from arthropods. We conclude that these G protein-coupled receptors (GPCRs) are closely related and have...... limpet Lottia gigantea (pQIHFSPTWGSamide), the oyster Crassostrea gigas (pQVSFSTNWGSamide), and the freshwater pearl mussel Hyriopsis cumingii (pQISFSTNWGSamide). We also found AKHs in the tardigrade Hysibius dujardini (pQLSFTGWGHamide), the rotifer Brachionus calycifloros (p...

  4. Uptake and accumulation of exogenous docosahexaenoic acid by Chlorella.

    Science.gov (United States)

    Hayashi, M; Yukino, T; Maruyama, I; Kido, S; Kitaoka, S

    2001-01-01

    Tuna oil or its hydrolysate was added to a culture of Chlorella for its nutritional fortification as a feed for rotifer. Exogenous docosahexaenoic acid (DHA) in its free form was taken up by the cells of Chlorella vulgaris strain K-22 and by other strains, but tuna oil was not taken up by the cells. Accumulated DHA was found by electron microscopy in the cells in oil droplets. All strains of Chlorella used in these experiments took up exogenous DHA into the cells. It seems that the structure of the cell wall did not affect the uptake of DHA into the Chlorella cells.

  5. MORPHOLOGICAL DEVELOPMENT OF Napoleon WRASSE, Cheilinus undulatus LARVAE

    Directory of Open Access Journals (Sweden)

    Jhon Harianto Hutapea

    2006-12-01

    Full Text Available To improve the survival rate, napoleon wrasse larval rearing trial was conducted at Research Institute for Mariculture, Gondol-Bali in 2003. The trial aims at assessing initial feed for larvae, food habit, and morphological development from early larval stage to juvenile. The results showed that chicken egg yolk could be applied as initial feed and followed by rotifer, Artemia and mysid (Mesophodopsis sp.. Three swimming behavior of larvae were observed, drifting, free swimming and hiding on the substrate as larvae develop. Digestive system development, simple tube like, transition stage and coiled where digestive system could be distinguished between stomach, intestine and rectum.

  6. 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.

  7. 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.

  8. Zooplankton-based assessment of the trophic state of a tropical forest river in Nigeria

    Directory of Open Access Journals (Sweden)

    Imoobe T.O.T.

    2009-01-01

    Full Text Available In this study, we explore the usefulness of zooplankton as a tool for assessing the trophic status of a Nigerian forest river. The river was sampled monthly and investigated for water physico-chemistry and zooplankton community structure using basic statistical measurement of diversity indices to characterize the zooplankton fauna. The trophic sta­tus of the river evaluated from its physico-chemical parameters indicates that the river is oligotrophic. The zooplankton composition was typical of a tropical freshwater river, with a total of 40 species, made up of 16 rotifers, 12 cladocerans, and 12 copepods and their developing stages in the following order of dominance: Rotifera > Cladocera > Cyclopoida > Calanoida. There were strong correlations between the lake's trophic status and its zooplankton communities. The zoo­plankton community was dominated by numerous species of rotifers and crustaceans, which are typical of oligotrophic to mesotrophic systems, such species including Conochilus dossuarius and Synchaeta longipes. However, the most dominant zooplankton species in West African freshwater ecosystems, viz., Keratella tropica, Keratella quadrata, Brachionus angularis, Trichocerca pusilla, Filinia longiseta, Pompholyx sulcata, and Proales sp., and others that are indicator species of high trophic levels, were not recorded in the river. The river is very clear and can be used for all manner of recreational activities.

  9. Toxic and genotoxic evaluation of six antibiotics on non-target organisms.

    Science.gov (United States)

    Isidori, Marina; Lavorgna, Margherita; Nardelli, Angela; Pascarella, Luigia; Parrella, Alfredo

    2005-06-15

    The ecotoxicity of the following six antibiotics on aquatic organisms was investigated: Erythromycin, Oxytetracyclin, Sulfamethoxazole, Ofloxacin, Lincomycin and Clarithromycin. Bioassays were performed on bacteria, algae, rotifers, microcrustaceans and fish to assess acute and chronic toxicity, while SOS Chromotest and Ames test were used to detect the genotoxic potential of the investigated drugs. For risk assessment, the environmental impact was calculated by MEC/PNEC ratio using the available data from the literature regarding their occurrence in the aquatic environment and the toxicity data obtained from the bioassays performed. The ecotoxicological results showed that acute toxicity was in the order of mg/L while, for the chronic data the antibiotics were bioactive at concentrations in the order of microg/L, mainly for the algae. Drugs investigated were one or two order of magnitude less active against rotifers and crustaceans. Ofloxacin was the only genotoxic compound and Sulfamethoxazole, Ofloxacin and Lincomycin were mutagenic. As for environmental risk, the macrolides were found to be the most harmful for the aquatic environment.

  10. 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.

  11. 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.

  12. 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.

  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. 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).

  15. 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.

  16. Higher rates of sex evolve in spatially heterogeneous environments.

    Science.gov (United States)

    Becks, Lutz; Agrawal, Aneil F

    2010-11-04

    The evolution and maintenance of sexual reproduction has puzzled biologists for decades. Although this field is rich in hypotheses, experimental evidence is scarce. Some important experiments have demonstrated differences in evolutionary rates between sexual and asexual populations; other experiments have documented evolutionary changes in phenomena related to genetic mixing, such as recombination and selfing. However, direct experiments of the evolution of sex within populations are extremely rare (but see ref. 12). Here we use the rotifer, Brachionus calyciflorus, which is capable of both sexual and asexual reproduction, to test recent theory predicting that there is more opportunity for sex to evolve in spatially heterogeneous environments. Replicated experimental populations of rotifers were maintained in homogeneous environments, composed of either high- or low-quality food habitats, or in heterogeneous environments that consisted of a mix of the two habitats. For populations maintained in either type of homogeneous environment, the rate of sex evolves rapidly towards zero. In contrast, higher rates of sex evolve in populations experiencing spatially heterogeneous environments. The data indicate that the higher level of sex observed under heterogeneity is not due to sex being less costly or selection against sex being less efficient; rather sex is sufficiently advantageous in heterogeneous environments to overwhelm its inherent costs. Counter to some alternative theories for the evolution of sex, there is no evidence that genetic drift plays any part in the evolution of sex in these populations.

  17. Studies on growth and survival of Oxyeleotris marmorata larva in food transformation period%云斑尖塘鳢转饵期仔鱼生长和存活率的研究

    Institute of Scientific and Technical Information of China (English)

    木亮亮; 徐慈浩; 许爱娱; 高腾; 肖锐媛; 潘淦

    2015-01-01

    The effects of the different feeding strategy on growth and survival of artificial incubation Oxyeleotris marmorata larva was examined in food transformation period at the water temperature of (30 ±1) ℃.5 feeding groups included, the rotifer feeding group ( A) , the 70%rotifer and 30%artemia feeding group ( B) , the 50%rotifer and 50%artemia feed-ing group ( C) , the 30%rotifer and 70%artemia feeding group ( D) , and the artemia feeding group ( E) , respectively. The results showed that the feeding intensity of the Oxyeleotris marmorata larva was improved, with the increase of propor-tion of the artemia in mixed bait ( the proportion of rotifer corresponding lower) .So the feeding intensity ratio ( Ir/Ia) of rotifer and artemia in the bait changed along with change of food composition.In the mixed bait feeding, growth rate and weight gain rate were the highest in the group D, while the survival rate was less than 50%, which was higher than group E, but significantly lower than the other groups.The growth indicators of group C were slightly lower than group D, while the survival rate was (74.00 ±2.29)%and comprehensive index was significantly better than the other groups.When the rotifer and artemia each accounted for 50%, the total length, specific growth rate and survival rate of larvae (10 day age began feeding group) was (13.07 ±0.13) mm, (10.25 ±0.37)%/d and (82.14 ±0.72)%, respectively.The larval growth index was the best in this group.The results indicated that the best bait casting time was 10 days of age.At the same time, in food transformation stage, the best ratio was 50%rotifer and 50%artemia in mixed bait.%在水温(30±1)℃条件下对人工孵化的云斑尖塘鳢(Oxyeleotris marmorata)仔鱼进行转饵期不同投喂策略实验,对仔鱼生长和成活情况进行了研究,设计5个投喂组:轮虫投喂组( A组);70%轮虫+30%卤虫投喂组( B组);50%轮虫+50%卤虫投喂组( C组);30

  18. 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.

  19. 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.

  20. 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.

  1. A report on Lecanidae (Rotifera: Monogononta from Andhra Pradesh, India, including six new distribution records with notes on their contemporary taxonomic nomenclature

    Directory of Open Access Journals (Sweden)

    S.Z. Siddiqi

    2013-07-01

    Full Text Available The Lecane-species complex taxonomy the world over, witnessed a state of flux, causing confusion and controversies, among world taxonomists over the treatment of various subgenera, taxa and sub and or infraspecific categories of the species rich genus Lecane Nitzsch 1827, on the basis of structure/shape of key, morphological features like foot/toes, lorica, etc. The taxonomic scenario in India, relying heavily on the classical, divergent taxonomic approaches presented a picture of more chaos/confusion, following poor accessibility to contemporary revisionary studies until the recent past. Despite revisionary studies across the world, a few notable Indian studies continued to be burdened with old nomenclature. This short communication reports for the first time ever, 33 valid species of lecanid rotifers (Lecanidae, including six new distributional records from Greater Hyderabad region and the entire state of Andhra Pradesh too with comments on their current nomenclature. Further, limnobiological correlation between five physicochemical parameters and rotifer associations revealed, L. bulla, L. closterocerca, L. hamata, L. ludwigi, L. luna and L. papuana as euryokous species, showing tolerance to a wide range of abiotic factors and habitats too.

  2. Transmission of lymphocystis disease virus to cultured gilthead seabream, Sparus aurata L., larvae.

    Science.gov (United States)

    Cano, I; Valverde, E J; Garcia-Rosado, E; Alonso, M C; Lopez-Jimena, B; Ortiz-Delgado, J B; Borrego, J J; Sarasquete, C; Castro, D

    2013-06-01

    The transmission of lymphocystis disease virus (LCDV) to gilthead seabream, Sparus aurata L., larvae was investigated using fertilized eggs from a farm with previous reports of lymphocystis disease. LCDV genome was detected by PCR-hybridization in blood samples from 17.5% of the asymptomatic gilthead seabream broodstock analysed. Using the same methodology, eggs spawned from these animals were LCDV positive, as well as larvae hatched from them. The presence of infective viral particles was confirmed by cytopathic effects development on SAF-1 cells. Whole-mount in situ hybridization (ISH) and immunohistochemistry (IHC) showed the presence of LCDV in the epidermis of larvae hatched from LCDV-positive eggs. When fertilized eggs were disinfected with iodine, no viral DNA was detected either in eggs (analysed by PCR-hybridization) or in larvae (PCR-hybridization and ISH). These results suggest the vertical transmission of LCDV, the virus being transmitted on the egg surface. Larvae hatched from disinfected eggs remain LCDV negative during the endotrophic phase, as showed by PCR-hybridization, ISH and IHC. After feeding on LCDV-positive rotifers, viral antigens were observed in the digestive tract, which suggests that viral entry could be achieved via the alimentary canal, and that rotifers can act as a vector in LCDV transmission to gilthead seabream larvae.

  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. 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

  6. Effects of DDT and dicofol on population growth of Brachionus calyciflorus under different algal (Scenedesmus obliquus) densities.

    Science.gov (United States)

    Xu, Xiao-Ping; Xi, Yi-Long; Chu, Zhao-Xia; Xiang, Xian-Ling

    2014-09-01

    A number of organochlorine pesticides, including DDT and dicofol, used to be important in crop protection and management. Their residues may reach water bodies and eventually affect the non-target organisms such as rotifers. In the present study, we evaluated the effects of DDT (0.05, 0.1, 0.2 and 0.4 mg l(-1)) and dicofol (0.1, 0.2, 0.4 and 0.8 mg l(-1)) on the population growth of rotifer Brachionus calyciflorus under two levels of Scenedesmus obliquus (1.0 x 10(6) and 3.0 x 10(6) cell ml(-1)). Regardless of the food level, DDT was more toxic than dicofol to B. calyciflorus. Under low food level, DDT at 0.1 and 0.2 mg l(-1) decreased the population growth rate (r), and DDT at 0.05-0.4 mg l(-1) decreased the maximum population density (K). Dicofol at 0.4 and 0.8 mg l(-1) decreased r and K, but dicofol at 0.2 mg l(-1) increased K. Under high food level, DDT at 0.05-0.2 mg l(-1) increased K, whereas DDT at 0.4 mg l(-1) as well as dicofol at 0.4 and 0.8 mg l(-1) decreased r and K. Increase in food level increased r exposed to DDT at 0.05-0.2 mg l(-1) as well as dicofol at 0.8 mg l(-1), and Kexposed to DDTat 0.05-0.2 mg l(-1) as well as dicofol at 0.1 and 0.2 mg l(-1). DDT concentration, algal density and their interaction affected r and K of B. calyciflorus. Both dicofol concentration and algal density affected r. Dicofol concentration, algal density and their interaction affected K. Both r and K were suitable endpoints for assessing the effects of DDT and dicofol on the rotifers population dynamics under two algal densities, and the latter was more sensitive.

  7. 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

  8. Coal fly ash effluent affects the distributions of Brachionus calyciflorus sibling species.

    Science.gov (United States)

    Zhang, Gen; Xi, Yi-Long; Xue, Ying-Hao; Xiang, Xian-Ling; Wen, Xin-Li

    2015-02-01

    Fly ash, a coal combustion residue of thermal power plants and a source of multiple pollutants, has been recognized as an environmental hazard all over the world. Although it is known that fly ash effluent affects density, diversity and distribution of rotifers in drainage systems and receiving water bodies, the effect of fly ash effluent on the distributions of highly similar rotifer species remains unknown. In this study, the mtDNA COI genes of 90 individuals in Brachionus calyciflorus complex from Lake Hui (as a fly ash discharge water pond) and other two neighboring lakes (Lake Fengming and Lake Tingtang) were sequenced and analyzed, and the responses in selected life table demographic parameters (life expectancy at hatching, net reproductive rate, intrinsic rate of population increase and proportion of sexual offspring) of different rotifer populations to fly ash effluent were investigated. Overall, 72 mtDNA haplotypes were defined, and were split into two clades by the phylogenetic trees. The divergence of COI gene sequences between the two clades ranged from 11.8% to17.8%, indicating the occurrence of two sibling species (sibling species I and sibling species II). Sibling species I distributed in all the three lakes, showing strong capabilities for dispersal and colonization, which were supported by its higher level of gene flow (2.60-4.04) between the populations from Lake Hui and each of the other two lakes, longer life expectancy at hatching (101.6-148.2 h), and higher net reproductive rate (4.4-16.4 offspring/female) and intrinsic rate of population increase (0.60-0.98/d) when cultured in aerated tap water and fly ash effluent. Sibling species II distributed in both Lake Tingtang and Lake Fengming, showing that its dispersal existed between the two lakes. Considering that the distance between Lake Hui and Lake Fengming is shorter than that between Lake Tingtang and Lake Fengming, sibling species II is able to disperse at least from Lake Fengming to Lake

  9. The most acidified Austrian lake in comparison to a neutralized mining lake.

    Science.gov (United States)

    Moser, Michael; Weisse, Thomas

    2011-12-01

    This study investigated two mining lakes located in the north of Lower Austria. These lakes arose 45 years ago when open cast lignite mining ceased. The lakes are separated by a 7-m wide dam. Due to the oxidation of pyrite, both lakes have been acidified and exhibit iron, sulphate, and heavy metal concentrations several orders of magnitude higher than in circumneutral lakes. The water column of both lakes is divided into two layers by a pronounced chemocline. The smaller mining lake (AML), with pH close to of 2.6, is the most acidic lake in Austria, whereas flooding with stream water and by drainage from the surrounding fields neutralized the adjacent larger pit lake. The goal of our study was to investigate the effect of flooding on its physical, chemical and biological properties, in comparison to the pristine AML. Even relative to other extremely acidic lakes, the flora and fauna in the AML was reduced and composed of only two flagellate, one ciliate, and one rotifer species. The simplified pelagic food web in the mixolimnion consisted of heterotrophic bacteria, the mixotrophic flagellates Chlamydomonas acidophila and Ochromonas sp., the ciliate Oxytricha sp., and the rotifer Cephalodella sp. The latter two are as yet undescribed new species. The heliozoan Actinophrys sp. that may act as top predator occurred only in low abundance. The euglenid Lepocinclis buetschlii formed a stable deep chlorophyll maximum (DCM) at 7 m depth. Highest cell numbers of L. buetschlii in the DCM exceeded 10(8) L(-1). The neutralized mining lake harboured higher plankton diversity similar to that of natural circumneutral lakes. A peak of at least 16 different phytoplankton taxa was observed during summer. The zooplankton consisted of several copepod species, daphnids and other cladocerans, and at least six different rotifer species. Several fish species occurred in the neutralized lake. Although the effect of non-permanent flooding was largely sustainable, interannual fluctuations

  10. 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.

  11. An ecotoxicological analysis of the sediment quality in a European Atlantic harbor emphasizes the current limitations of the Water Framework Directive.

    Science.gov (United States)

    Gonçalves, Sandra F; Calado, Ricardo; Gomes, Newton C M; Soares, Amadeu M V M; Loureiro, Susana

    2013-07-15

    The "PortoNovo" project was developed to standardize the methodologies for water quality management in the port areas of coastal Atlantic regions to improve the Water Frame Directive (WFD) for these specific water bodies. Under this scope, water and sediment samples were collected from five sites within the Port of Aveiro, Portugal. According to the physical and chemical parameters that were analyzed (i.e., metals, total organic carbon, polychlorinated biphenyls and polycyclic aromatic hydrocarbons), the sediments were not considered at risk based on European sediment quality laws. However, the bioassays that were performed on the sediment samples (Microtox®) and the standardized acute toxicity test using the marine rotifer, Brachionus plicatilis, on sediment elutriates revealed higher toxicity levels. The use of bioassays to assess sediment quality clearly complements more conservative approaches and highlights current gaps within the WFD. The approach presented here can be easily transferred to other port areas for more reliable water quality management.

  12. Economic Analysis on Key Challenges for Sustainable Aquaculture Development

    DEFF Research Database (Denmark)

    Gedefaw Abate, Tenaw

    developmental stage. The key challenge in this regard is that the conventional used live feed items, Artemia and rotifers, are nutritionally deficient. Thus, the first main purpose of the thesis is carrying out an economic analysis of the feasibility of commercial production and the use of an alternative live...... challenges that could obstruct its sustainable development, such as a lack of suitable feed, which includes fishmeal, fish oil and live feed, and negative environmental externalities. If the aquaculture industry is to reach its full potential, it must be both environmentally and economically sustainable....... To this end, key challenges should be thoroughly examined to identify sustainable and efficient solutions. Thus, the thesis focuses on two important bottlenecks in the growth of the aquaculture sector—namely, lack of nutritionally suitable live feed items for marine finfish production and negative...

  13. 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

  14. Transmission of specific groups of bacteria through water distribution system.

    Science.gov (United States)

    Grabińska-Łoniewska, Anna; Wardzyńska, Grazyna; Pajor, Elzbieta; Korsak, Dorota; Boryń, Krystyna

    2007-01-01

    Microbial contamination of a water distribution system was examined. The number and the taxonomy of non-pigmented and pigmented heterotrophic bacteria (HB), number of bacteria (Pseudomonas sp., Enterococcus sp., Campylobacter sp., Yersinia sp., representatives of the Enterobacteriaceae, coagulase-positive staphylococci, and C. pefringens) in the bulk water phase, biomass of zoogloeal aggregates of bacteria, fungi, algae, protozoa and rotifers (ZABFAPR) (separated from the above on 5 microm pore size filters) and in pipe sediments was determined. An increased number of HB occurred at the sampling sites situated as close as 4.2 km to the Water Treatment Plant (WTP), and was especially significant at 10.3 km. It was shown that the main reservoir of hygienically relevant bacteria did not occur in the water phase which is monitored in routine control analyses carried out by the WTP laboratories, but in the ZABFAPR biomass not monitored so far.

  15. 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.

  16. Resource Partitioning Among Planktivorous Fish Larvae and Fry in a Mediterranean Coastal Lagoon

    Science.gov (United States)

    Gisbert, E.; Cardona, L.; Castelló, F.

    1996-12-01

    Resource partioning among the planktivorous stages of eight fish species occurring in a Mediterranean coastal lagoon was studied. Five species were migratory mullets that spawned in the sea ( Liza ramada, L. aurata, L. saliens, Chelon labrosusand Mugil cephalus), while the other three species were resident and spawned in the lagoon ( Atherina boyeri, Cyprinus carpioand Gambusia holbrooki). Mullet fry exhibited similar diets, based on the consumption of zooplanktonic Crustacea such as copepods and cladocerans, although adult chironomids were also important. Gambusia holbrookiand A. boyerifed on small prey such as copepod nauplii, copepodites and rotifers, while C. carpioconsumed larger prey preferentially (cladocerans and copepods). According to the trophic overlap and niche width results, seven species pairs could be competing in the estuary, although further experimental evidence is still required.

  17. 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

  18. Disentangling the benefits of sex.

    Science.gov (United States)

    Roze, Denis

    2012-01-01

    Understanding the evolutionary advantage of sexual reproduction remains one of the most fundamental questions in evolutionary biology. Most of the current hypotheses rely on the fact that sex increases genetic variation, thereby enhancing the efficiency of natural selection; an important body of theoretical work has defined the conditions under which sex can be favoured through this effect. Over the last decade, experimental evolution in model organisms has provided evidence that sex indeed allows faster rates of adaptation. A new study on facultatively sexual rotifers shows that increased rates of sex can be favoured during adaptation to new environmental conditions and explores the cause of this effect. The results provide support for the idea that the benefits of increasing genetic variation may compensate for the short-term costs of sexual reproduction.

  19. Economic feasibility of copepod production for commercial use

    DEFF Research Database (Denmark)

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

    2015-01-01

    condition, reduces mal-pigmentation and allows breeding of ‘new’ marine finfish species. However, copepods are not yet commercially produced and therefore not widely used in the aquaculture industry. One of the bottlenecks for large-scale production has been lack of economic knowledge on the feasibility...... of producing copepods for commercial application. This is the first empirical study to investigate the economic feasibility of copepod production for commercial use. To this end, a standard cost-benefit analysis based on a prototype production facility of Acartia tonsa (Dana) eggs at Roskilde University......, 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...

  20. Ingestion and transfer of microplastics in the planktonic food web.

    Science.gov (United States)

    Setälä, Outi; Fleming-Lehtinen, Vivi; Lehtiniemi, Maiju

    2014-02-01

    Experiments were carried out with different Baltic Sea zooplankton taxa to scan their potential to ingest plastics. Mysid shrimps, copepods, cladocerans, rotifers, polychaete larvae and ciliates were exposed to 10 μm fluorescent polystyrene microspheres. These experiments showed ingestion of microspheres in all taxa studied. The highest percentage of individuals with ingested spheres was found in pelagic polychaete larvae, Marenzelleria spp. Experiments with the copepod Eurytemora affinis and the mysid shrimp Neomysis integer showed egestion of microspheres within 12 h. Food web transfer experiments were done by offering zooplankton labelled with ingested microspheres to mysid shrimps. Microscopy observations of mysid intestine showed the presence of zooplankton prey and microspheres after 3 h incubation. This study shows for the first time the potential of plastic microparticle transfer via planktonic organisms from one trophic level (mesozooplankton) to a higher level (macrozooplankton). The impacts of plastic transfer and possible accumulation in the food web need further investigations.

  1. Nutritious supplements to aquacultural seedling and food organism%鱼虾贝苗饵料生物的营养强化

    Institute of Scientific and Technical Information of China (English)

    陈世杰

    2001-01-01

    The article emphasizes importance of nutrition of feeding of aquaculture for cultivation of aquacuitural seedling and food organisms . It raises point of supplementary nutrition . It alsorectifies errors in nutritions feeding on ways and methods of nutritions supplements to micro-algae,rotifer and Artemia etc. Finally , the author analizes varieties and overlapping time of aquacultural seedling menu.%本文强调鱼虾贝苗饵料生物营养的重要性,提出营养强化新问题.并就微藻、轮虫、卤虫等的营养强化方式方法,校正其投饲中的营养误区,以及水产苗种饵料系列中的品种及交迭时间进行分析.

  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...... (photobioreactor - PBR). There is an increasing interest in using closed PBRs for algae cultivation since this culture system provides a better control of cultivation conditions and enables higher algae productivity. Among the marine microalgae, the cryptophyte Rhodomonas salina is one of the optimal feed...... for copepods (Støttrup and Jensen, 1990; Zhang et al., 2013). Despite the benefit of using R. salina in cultivation of copepods, to our knowledge, there is no report on the production of this microalga at industrial scale to supply sufficient food for mass production of copepods. We intend to conduct the basic...

  3. Changes in a large regulated tropical river: The Paraná River downstream from the Porto Primavera Dam, Brazil

    Science.gov (United States)

    Stevaux, José C.; Martins, Débora P.; Meurer, M.

    2009-12-01

    Dams disturb in the fluvial dynamics by changing the natural cycle of the rivers, interfering with the transport-deposition processes and affecting river ecology. The Brazilian part of the Paraná Basin has the largest hydrometrical power potential of the country with more than 150 hydroelectric power dams that transformed the Paraná River and its tributaries in a succession of lakes. This research aims to analyze the changes in certain fluvial variables in the last natural downstream reach of the Upper Paraná River after closure of the Porto Primavera Dam. Data acquired before and after dam construction showed changes in water discharge, bank erosion, flood pulse, bed load grain size discharge, concentration of suspended load and bedform morphology and size. Those alterations generated changes in river ecology especially on fish reproduction, benthic community, and rotifers variety and density. A review of the obscure regional literature, generally in Portuguese, is also presented.

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

    Energy Technology Data Exchange (ETDEWEB)

    Almquist, Elisabeth

    1970-11-15

    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

  5. 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 (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.

  6. Early life stages of fish and the relationships with zooplankton in a tropical Brazilian reservoir: Lake Monte Alegre.

    Science.gov (United States)

    Meschiatti, A J; Arcifa, M S

    2002-02-01

    For evaluating the trophic relationship between early life stages of fish and zooplankton in Lake Monte Alegre, fish distribution and feeding habits have been studied in areas with and without macrophytes. In the first of these areas, 356 specimens belonging to 8 species, mostly juveniles, were caught by a sieve. Another 35 specimens, belonging to 4 species, were caught by gill nets and seine in areas lacking macrophytes. Their diets were composed of aquatic insects, microcrustaceans, rotifers, detritus, and other aquatic invertebrates. Microcrustacean prey were mainly littoral or benthic dwellers, found in the highest proportion in specimens of 7-20 mm SL. Most fish species have parental care, which could explain the absence of planktonic larvae. Early life stages of fish do not exert a predation pressure on the lake zooplankton.

  7. 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”.

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

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    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.

  9. Zebra mussels (Dreissena polymorpha) limit food for larval fish (Pimephales promelas) in turbulent systems: A bioenergetics analysis

    Science.gov (United States)

    Bartsch, L.A.; Richardson, W.B.; Sandheinrich, M.B.

    2003-01-01

    We conducted a factorial experiment, in outdoor mesocosms, on the effects of zebra mussels and water column mixing (i.e., turbulence) on the diet, growth, and survival of larval fathead minnows (Pimephales promelas). Significant (P zebra mussels, whereas mortality was 37% in treatment with turbulence and 17% and 18% in the zebra mussels treatment, and the control, respectively. The size of individual fish was significantly different among treatments at the end of the experiment and was inversely related to survival. Levels of trophic resources (i.e., phyto and zooplankton) varied among treatments and were treatment specific. Turbulent mixing facilitated removal of phytoplankton by zebra mussels by making the entire water column of the tanks available to these benthic filter feeders. Early in the experiment (Day = 0 to 14) the physical process of turbulent mixing likely caused a reduction in standing stocks of zooplankton. The interactive effect of turbulence and mussels reduced copepod and rotifer stocks, through physical processes and through filtration by zebra mussels, relative to the turbulence treatment. The reductions in the number of total zooplankton in the turbulent mixing mesocosms and the further reduction of rotifer and copepod in the turbulence and mussels treatment coincided with a period of increased reliance of larval fathead minnows on these prey. Estimates of consumption from bioenergetics modeling and measured prey standing stocks indicated caloric resources of suitable prey in turbulence treatments during the early weeks of the experiment were insufficient to prevent starvation. Early mortality in the turbulence and mussels treatment likely released surviving fish from intense intraspecific competition and resulted in higher individual growth rates. A combination of high abundance of zebra mussels in an environment with a well-mixed water column can have significant effects on larval fish survival and growth.

  10. 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.

  11. 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

  12. Field and laboratory studies on the impact of two Bt rice lines expressing a fusion protein Cry1Ab/1Ac on aquatic organisms.

    Science.gov (United States)

    Wang, Yongmo; Huang, Jiacheng; Hu, Huawei; Li, Jianhong; Liu, Biao; Zhang, Guoan

    2013-06-01

    Genetically modified (GM) rice expressing Bt toxins is at the edge of commercial release in China. However, little information is available concerning the impact of Bt rice on aquatic organisms which are abundant in paddy field. A two-year study was conducted to assess the effects of two GM rice lines expressing a fusion protein Cry1Ab/1Ac (Bt rice) on three groups of zooplankton, rotifers, cladocerans and copepods in field conditions. Multi-factor ANOVA revealed that the population densities of rotifers, cladocerans and copepods in paddy field varied significantly between years and rice developmental stages, but did not differ significantly between Bt and non-Bt rice treatments. In all the field investigations, only one significant difference was found on copepods in the tillering stage of 2009, but the difference was not related to the presence of the Cry toxin. Under open-air conditions, we simulated the farming practice of straw mulch, using Bt rice straw as a food source for the water flea Daphnia hyalina. After one and two months of culture, the density of D. hyalina did not differ between Bt rice treatments and non-Bt rice treatments. A laboratory experiment found that purified Bt toxins Cry1Ab and Cry1Ac had no toxic effect on D. hyalina even in the treatment in which the Bt toxin concentration was as high as 2500ng/ml. Those above results indicate that the two Bt rice lines have no negative effect on the three groups of zooplankton. However, further studies are needed to compare the effects of Bt rice and non-Bt rice on the paddy zooplankton community in the context of integrated pest management which includes the use of pesticides.

  13. 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.

  14. Mesozooplankton grazing on picocyanobacteria in the Baltic Sea as inferred from molecular diet analysis.

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    Nisha H Motwani

    Full Text Available Our current knowledge on the microbial component of zooplankton diet is limited, and it is generally assumed that bacteria-sized prey is not directly consumed by most mesozooplankton grazers in the marine food webs. We questioned this assumption and conducted field and laboratory studies to examine picocyanobacteria contribution to the diets of Baltic Sea zooplankton, including copepods. First, qPCR targeting ITS-1 rDNA sequence of the picocyanobacteria Synechococcus spp. was used to examine picocyanobacterial DNA occurrence in the guts of Baltic zooplankton (copepods, cladocerans and rotifers. All field-collected zooplankton were found to consume picocyanobacteria in substantial quantities. In terms of Synechococcus quantity, the individual gut content was highest in cladocerans, whereas biomass-specific gut content was highest in rotifers and copepod nauplii. Moreover, the gut content in copepods was positively related to the picocyanobacteria abundance and negatively to the total phytoplankton abundance in the water column at the time of sampling. This indicates that increased availability of picocyanobacteria resulted in the increased intake of this prey and that copepods may rely more on picoplankton when food in the preferred size range declines. Second, a feeding experiments with a laboratory reared copepod Acartia tonsa fed a mixture of the picocyanobacterium Synechococcus bacillaris and microalga Rhodomonas salina confirmed that copepods ingested Synechococcus, even when the alternative food was plentiful. Finally, palatability of the picocyanobacteria for A. tonsa was demonstrated using uptake of (13C by the copepods as a proxy for carbon uptake in feeding experiment with (13C-labeled S. bacillaris. These findings suggest that, if abundant, picoplankton may become an important component of mesozooplankton diet, which needs to be accounted for in food web models and productivity assessments.

  15. Zooplankton community resilience after press-type anthropogenic stress in temporary ponds.

    Science.gov (United States)

    Angeler, David G; Moreno, José M

    2007-06-01

    Temporary ponds are physically disturbed environments that fluctuate on seasonal and interannual scales. These ecosystems are also susceptible to anthropogenic perturbation such as contamination inputs. However, the interactive effects of natural disturbance and anthropogenic stress on ecosystem processes and community dynamics have hardly been assessed in these ecosystem types. We used a multiple before-after control-impact (MBACI) design to study zooplankton community recovery from low and high inputs of a fire retardant in artificially constructed ponds over three hydroperiods. The retardant caused a decline in species richness and an increase in rotifers during summer and winter months relative to controls and pretreatment dates, and the duration of these changes varied among retardant treatments. In nonmetric, multidimensional scaling analyses the increased rotifer densities were reflected in loops that showed recurring deviations from and (upon collapse) approaches to reference conditions, while the effects of the anthropogenic stressor persisted in the ponds. The amplitudes of fluctuation followed no regular patterns; it varied with retardant treatment level and was higher in the third hydroperiod compared to the second in one of the treatments. From a temporal perspective, this non-dampened pattern suggests a new cause-effect mechanism for disturbance ecology, which we refer to as a "protracted press disturbance, roller coaster response" relationship. This model emphasizes stochastic oscillations in community composition, punctuated by periods in which the community approaches reference conditions. From the applied viewpoint, this model suggests that the accurate detection of perturbation and the implementation of sound management and restoration strategies will require intensive sampling designs that span multiple hydroperiods in persistently degraded ponds.

  16. Are algae relevant to the detritus-based food web in tank-bromeliads?

    Science.gov (United States)

    Brouard, Olivier; Le Jeune, Anne-Hélène; Leroy, Céline; Cereghino, Régis; Roux, Olivier; Pelozuelo, Laurent; Dejean, Alain; Corbara, Bruno; Carrias, Jean-François

    2011-01-01

    We assessed the occurrence of algae in five species of tank-bromeliads found in contrasting environmental sites in a Neotropical, primary rainforest around the Nouragues Research Station, French Guiana. The distributions of both algal abundance and biomass were examined based on physical parameters, the morphological characteristics of bromeliad species and with regard to the structure of other aquatic microbial communities held in the tanks. Algae were retrieved in all of the bromeliad species with mean densities ranging from ∼10(2) to 10(4) cells/mL. Their biomass was positively correlated to light exposure and bacterial biomass. Algae represented a tiny component of the detrital food web in shaded bromeliads but accounted for up to 30 percent of the living microbial carbon in the tanks of Catopsis berteroniana, located in a highly exposed area. Thus, while nutrient supplies are believed to originate from wind-borne particles and trapped insects (i.e., allochtonous organic matter), our results indicate that primary producers (i.e., autochtonous organic matter) are present in this insectivorous bromeliad. Using a 24-h incubation of size-fractionated and manipulated samples from this plant, we evaluated the impact of mosquito foraging on algae, other microorganisms and rotifers. The prey assemblages were greatly altered by the predation of mosquito larvae. Grazing losses indicated that the dominant algal taxon, Bumilleriopsis sp., like protozoa and rotifers, is a significant part of the diet of mosquito larvae. We conclude that algae are a relevant functional community of the aquatic food web in C. berteroniana and might form the basis of a complementary non-detrital food web.

  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. 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.

  19. 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

  20. 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.

  1. 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.

  2. Does copepods influence dusky grouper (Epinephelus marginatus early development?

    Directory of Open Access Journals (Sweden)

    Monica Mateus

    2014-06-01

    Full Text Available Good knowledge on the development of early life stages is essential for successful conservation programs of threatened fish species. Diet and rearing system affects early life survival and juvenile quality. Copepods are the natural food of fish larvae in the wild possessing high nutritional value, when compared with live feeds used in aquaculture (rotifers and artemia, and a wide range of size classes. Rearing systems with low water column disturbance and low larval densities enhanced the survival of fragile fish larvae. The aim of this work is to evaluate the effect of the introduction of copepods in the diet of early dusky grouper larvae reared in controlled mesocosm systems using larval development and juvenile quality as indicators. Two feeding protocols were tested, one composed only by rotifers (Brachionus plicatilis, brine shrimp (Artemia spp. and dry feed and the other supplemented with copepods (Paracartia grani from mouth opening (2 day after hatching - DAH to 8 DAH. Feeding behavior, growth, survival, skeletal malformations and digestive enzymes activity was assessed at different developmental stages. The addition of copepods to the early larvae diet of dusky grouper resulted in faster development and higher survival rates. Larvae fed with copepods improved their development. At 20 DAH all larvae reared at the mesocosm with copedods were already at the stage of post-flexion while in the system without copepods this stage was attained later. At 25 DAH only 64% of the larvae were in post flexion in the mesoscosm without copepods. At 30 DAH larvae supplemented with copepods attained an acidic digestion (high specific activity of pepsin earlier than at the system without copepods. In this last system alkaline digestion (trypsin specific activity, characteristic of early larval stages, was significantly higher reinforcing the faster development of larvae fed with copepods. In both systems the incidence of skeletal malformations was low.

  3. 温度和食物密度对两种形态型裂足臂尾轮虫(Brachionus diversicornis)生活史特征和后代形态型的影响%Effects of temperature and algal density on life history characteristics and morphotype in offspring of two Brachionus diversicomis morphotypes

    Institute of Scientific and Technical Information of China (English)

    马杰; 席贻龙; 许丹丹; 葛雅丽

    2011-01-01

    ) and Scenedesmus obliquus density( 0.75×106, 1.5×106,3.0× 106 and 6.0 ×106 cells/ml) on life history parameters including net reproductive rate, intrinsic rate of population increase, generation time, life expectancy at hatching and proportion of mictic offspring, and morphotype in offspring of two Brachionus diversicornis morphotypes were studied by means of individual culture.The results showed that at the four temperatures, the survivorship between the two B. Diversicornis morphotypes was similar. The fecundities of the equal-spined rotifers at 15℃ , 25℃ and 30℃ were significantly higher than those of the unequal-spined rotifer. Each of the life history parameters between the two B. Diversicornis morphotypes was similar, except that the generation time of the equal-spined rotifers was longer than that of the unequal-spined rotifers at 30℃. The survivorship, the fecundity and each of all the life history parameters between the two B. Diversicornis morphotypes were also similar at the four food densities. All the intrinsic rate of population increased, the generation time and the life ex-pectancy at hatching of the two B. Diversicornis morphotypes responded differently to increasing temperature, but food density only affected the net reproductive rate and the intrinsic rate of population increase of the equal-spined rotifers significantly. The net reproductive rate of the equal-spined rotifers at algal density of 6.0 × 106 cells/ml was lower than that at both 0.75 × 106 and 3.0 × 106 cells/ml, and the net reproductive rate at 1.5 × 106 cells/ml was similar with that at each of all the above-stated three food densities. The intrinsic rate of population increase of the equal-spined rotifers at 6.0 × 106 cells/ml was lower than that at 3.0 × 106 cells/ml, but both of them were similar with those at 0.75 × 106 and 1.5 × 106cells/ml. At each of the four temperatures and food densities, the two B. Diversicornis morphotypes produced both equal-and unequal

  4. 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

    Directory of Open Access Journals (Sweden)

    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

  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. 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

  8. 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

    Directory of Open Access Journals (Sweden)

    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.

  9. Klamath River Water Quality Data from Link River Dam to Keno Dam, Oregon, 2008

    Science.gov (United States)

    Sullivan, Annett B.; Deas, Michael L.; Asbill, Jessica; Kirshtein, Julie D.; Butler, Kenna D.; Vaughn, Jennifer

    2009-01-01

    biovolumes generally were highest at the upstream Link River and Railroad Bridge sites and decreased in the downstream direction. *Zooplankton densities were largest in late April. Populations were dominated by rotifers and copepods in early spring, and by rotifers and cladocerans in summer, with cladocerans most common at the most upstream site.

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

    Directory of Open Access Journals (Sweden)

    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

  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. The ghost of herbivory past: slow defence relaxation in the chlorophyte Scenedesmus obliquus

    Directory of Open Access Journals (Sweden)

    Jacobus VIJVERBERG

    2009-08-01

    Full Text Available The freshwater chlorophyte Scenedesmus obliquus (Turpin Kützing produces colonies as an inducible defence against herbivores. We investigated the dynamics of Scenedesmus colony formation and disintegration in response to the density of the herbivorous rotifer Brachionus calyciflorus in large-scale mesocosms. Additional bioassays were performed to investigate Scenedesmus colony disintegration under different light regimes. In the mesocosm experiment, colony formation took place rapidly, but relaxation towards the initial size took relatively long (>10 d after cessation of herbivory. In the bioassays, in the absence of infochemicals, colonies disintegrated almost immediately in the dark (1-1.5 d, within 4 d under a photoperiod of 16:8 (L:D and between 8 and 12 days under full light. Colony disintegration times in the mesocosm experiment were substantially longer as compared to treatments with the same photoperiod (L:D 16:8 in the bioassays. So after a peak of herbivory, the 'ghost of herbivory past', i.e. the remaining infochemicals, may continue to induce colony formation, causing an additional lengthening of colony disintegration times and associated fitness costs (higher sedimentation loss rates. This indicates that costs of colony formation are not only important during the induction phase, but may be even more important during the relaxation phase. We compared these sedimentation costs to the costs of herbivory for differently sized Scenedesmus, and found a clear trade-off pattern for these costs.

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

    Directory of Open Access Journals (Sweden)

    Marina Vera Diaz

    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.

  14. Recovery and reproduction of an Antarctic tardigrade retrieved from a moss sample frozen for over 30 years.

    Science.gov (United States)

    Tsujimoto, Megumu; Imura, Satoshi; Kanda, Hiroshi

    2016-02-01

    Long-term survival has been one of the most studied of the extraordinary physiological characteristics of cryptobiosis in micrometazoans such as nematodes, tardigrades and rotifers. In the available studies of long-term survival of micrometazoans, instances of survival have been the primary observation, and recovery conditions of animals or subsequent reproduction are generally not reported. We therefore documented recovery conditions and reproduction immediately following revival of tardigrades retrieved from a frozen moss sample collected in Antarctica in 1983 and stored at -20 °C for 30.5 years. We recorded recovery of two individuals and development of a separate egg of the Antarctic tardigrade, Acutuncus antarcticus, providing the longest records of survival for tardigrades as animals or eggs. One of the two resuscitated individuals and the hatchling successfully reproduced repeatedly after their recovery from long-term cryptobiosis. This considerable extension of the known length of long-term survival of tardigrades recorded in our study is interpreted as being associated with the minimum oxidative damage likely to have resulted from storage under stable frozen conditions. The long recovery times of the revived tardigrades observed is suggestive of the requirement for repair of damage accrued over 30 years of cryptobiosis. Further more detailed studies will improve understanding of mechanisms and conditions underlying the long-term survival of cryptobiotic organisms.

  15. Desiccation tolerance in the tardigrade Richtersius coronifer relies on muscle mediated structural reorganization.

    Science.gov (United States)

    Halberg, Kenneth Agerlin; Jørgensen, Aslak; Møbjerg, Nadja

    2013-01-01

    Life unfolds within a framework of constraining abiotic factors, yet some organisms are adapted to handle large fluctuations in physical and chemical parameters. Tardigrades are microscopic ecdysozoans well known for their ability to endure hostile conditions, such as complete desiccation--a phenomenon called anhydrobiosis. During dehydration, anhydrobiotic animals undergo a series of anatomical changes. Whether this reorganization is an essential regulated event mediated by active controlled processes, or merely a passive result of the dehydration process, has not been clearly determined. Here, we investigate parameters pivotal to the formation of the so-called "tun", a state that in tardigrades and rotifers marks the entrance into anhydrobiosis. Estimation of body volume in the eutardigrade Richtersius coronifer reveals an 87 % reduction in volume from the hydrated active state to the dehydrated tun state, underlining the structural stress associated with entering anhydrobiosis. Survival experiments with pharmacological inhibitors of mitochondrial energy production and muscle contractions show that i) mitochondrial energy production is a prerequisite for surviving desiccation, ii) uncoupling the mitochondria abolishes tun formation, and iii) inhibiting the musculature impairs the ability to form viable tuns. We moreover provide a comparative analysis of the structural changes involved in tun formation, using a combination of cytochemistry, confocal laser scanning microscopy and 3D reconstructions as well as scanning electron microscopy. Our data reveal that the musculature mediates a structural reorganization vital for anhydrobiotic survival, and furthermore that maintaining structural integrity is essential for resumption of life following rehydration.

  16. 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.

  17. 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.

  18. 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.

  19. Toxicity of two imidazolium ionic liquids, [bmim][BF4] and [omim][BF4], to standard aquatic test organisms: Role of acetone in the induced toxicity.

    Science.gov (United States)

    Tsarpali, Vasiliki; Dailianis, Stefanos

    2015-07-01

    The main goal of this study was to investigate the toxicity of the imidazolium-based ionic liquids (ILs), [bmim][BF4] (1-butyl-3-methylimidazolium tetrafluoroborate) and [omim][BF4] (1-octyl-3-methylimidazolium tetrafluoroborate), in battery of standard aquatic toxicity test organisms. Specifically, exposure of the algae Scenedesmus rubescens, crustaceans Thamnocephalus platyurus and Artemia franciscana, rotifers Brachionus calyciflorus and Brachionus plicatilis and bivalve Mytilus galloprovincialis to different concentrations of [bmim][BF4], [omim][BF4] and/or a binary mixture of [bmim][BF4]-[omim][BF4] (1:1) with or without acetone (carrier solvent), revealed that solvent can differentially mediate ILs' toxic profile. Acetone's ability to differentially affect ILs' cation's alkyl chain length, as well as the hydrolysis of [BF4(-)] anions was evident. Given that the toxic potency of the tested ILs seemed to be equal or even higher (in some cases) than those of conventional organic solvents, the present study revealed that the characterization of imidazolium-based ILs as "green solvents" should not be generalized, at least in case of their natural occurrence in mixtures with organic solvents, such as acetone.

  20. Non-random spatial coupling induces desynchronization, chaos and multistability in a predator-prey-resource system.

    Science.gov (United States)

    Suzuki, Kenta; Yoshida, Takehito

    2012-05-07

    The metacommunity perspective has attracted much attention recently, but the understanding of how dispersal between local communities alters their ecological dynamics is still limited, especially regarding the effect of non-random, unequal dispersal of organisms. This is a study of a three-trophic-level (predator-prey-resource) system that is connected by different manners of dispersal. The model is based on a well-studied experimental system cultured in chemostats (continuous flow-through culture), which consists of rotifer predator, algal prey and nutrient. In the model, nutrient dispersal can give rise to multistability when the two systems are connected by nutrient dispersal, whereas three-trophic-level systems tend to show a rich dynamical behavior, e.g. antisynchronous or asynchronous oscillations including chaos. Although the existence of multistability was already known in two-trophic-level (predator-prey) systems, it was confined to a small range of dispersal rate. In contrast, the multistability in the three-trophic-level system is found in a broader range of dispersal rate. The results suggest that, in three-trophic-level systems, the dispersal of nutrient not only alters population dynamics of local systems but can also cause regime shifts such as a transition to different oscillation phases.

  1. Form of an evolutionary tradeoff affects eco-evolutionary dynamics in a predator-prey system.

    Science.gov (United States)

    Kasada, Minoru; Yamamichi, Masato; Yoshida, Takehito

    2014-11-11

    Evolution on a time scale similar to ecological dynamics has been increasingly recognized for the last three decades. Selection mediated by ecological interactions can change heritable phenotypic variation (i.e., evolution), and evolution of traits, in turn, can affect ecological interactions. Hence, ecological and evolutionary dynamics can be tightly linked and important to predict future dynamics, but our understanding of eco-evolutionary dynamics is still in its infancy and there is a significant gap between theoretical predictions and empirical tests. Empirical studies have demonstrated that the presence of genetic variation can dramatically change ecological dynamics, whereas theoretical studies predict that eco-evolutionary dynamics depend on the details of the genetic variation, such as the form of a tradeoff among genotypes, which can be more important than the presence or absence of the genetic variation. Using a predator-prey (rotifer-algal) experimental system in laboratory microcosms, we studied how different forms of a tradeoff between prey defense and growth affect eco-evolutionary dynamics. Our experimental results show for the first time to our knowledge that different forms of the tradeoff produce remarkably divergent eco-evolutionary dynamics, including near fixation, near extinction, and coexistence of algal genotypes, with quantitatively different population dynamics. A mathematical model, parameterized from completely independent experiments, explains the observed dynamics. The results suggest that knowing the details of heritable trait variation and covariation within a population is essential for understanding how evolution and ecology will interact and what form of eco-evolutionary dynamics will result.

  2. 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.

  3. Effects on the population dynamics of Brachionus rubens (Rotifera) caused by mercury and cadmium administered through medium and algal food Chlorella vulgaris%在培养基和食料中添加铅和镉对轮虫种群动态的影响

    Institute of Scientific and Technical Information of China (English)

    S.S.S.SARMA; Hilda Fabiola NUNEZ-CRUZ; S.NANDINI

    2005-01-01

    Due to industrial activities,heavy metal concentrations in aquatic systems of Mexico,are on the rise.Zooplankton,particularly rotifers,being sensitive and common components of freshwater,are widely used in ecotoxicological tests for establishing water quality criteria.Depending on the route of exposure (i.e.via medium or algal food),the toxicity of heavy metals varies.In the present study we evaluated the effect of cadmium and mercury exposed through medium and via algal food for the rotifer B.rubens.For both the heavy metals,we exposed rotifers via medium containing Chlorella at 0.5×106 cells/ml or fed daily on previously exposed (1,2 and 4 h) alga to the toxicants (using 5 times the value of LC50 for B.rubens).For cadmium toxicity through medium,we used 3 toxicant levels (0.1,0.2 and 0.4 mg/L) and for mercury,we used 0.005,0.010 and 0.015 mg/L.Based on the LC50,B.rubens was 24 times more sensitive to mercury (0.035±0.002 mg/L) than cadmium.At a concentration of 0.4 mg/L,cadmium through the medium caused increased lag phase of B.rubens.When grown on Chlorella exposed for different durations to cadmium,the rotifer density decreased with the increasing duration of algal exposure to the heavy metal.When mercury was used in the medium or via algal food,the trends in the population growth of B.rubens were similar to those for cadmium.An increase in heavy metal concentration in the medium resulted in a decrease of the rate of population increase per day (r).The r varied from 0.33 (in control) to 0.02 d-1 (in heavy metal treatment) depending on the mode of exposure though medium or via algal food[Acta Zoologica Sinica 51(1):46-52,2005].%由于工业活动的影响,墨西哥水体环境中的重金属浓度在上升.浮游动物,尤其是轮虫类,由于对环境变化十分敏感而且是淡水中的常见组成部分,因此被广泛用于生态毒理试验以确定水质标准.在不同的胁迫途径下(如通过培养基或食料),重金属的毒性是不同的.在

  4. 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.

  5. 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.

  6. 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.

  7. Differential endozoochory of aquatic invertebrates by two duck species in shallow lakes

    Science.gov (United States)

    Valls, Luis; Castillo-Escrivà, Andreu; Barrera, Luis; Gómez, Eulalia; Gil-Delgado, José Antonio; Mesquita-Joanes, Francesc; Armengol, Xavier

    2017-04-01

    Animal vectors are essential for the movement of invertebrate resting eggs between water bodies. However, differences in habitat preferences and feeding behaviour between bird species may result in variations in the dispersal of invertebrates via these birds, even if the different bird species live in the same lake. To test such effects, faecal samples from Anas platyrhynchos (collected in autumn and spring) and Tadorna tadorna (collected in spring) were cultured in water at 20° C and 12 L: 12 D conditions in order to quantify the resting eggs which could be internally transported by these birds. One half of each faecal sample was initially cultured at a conductivity of 0.6 mS cm-1 and the other half at 6 mS cm-1. 1054 invertebrates hatched from a total of 60 faecal samples, including cladocerans, copepods, ostracods, rotifers and ciliates, with a wide variability among faeces. Autumn yielded a low proportion of samples with hatchlings (12.5%) compared to spring (90%). Significant differences were observed between birds, but not between conductivity treatments. Thus, our results imply different hatching dynamics affected by disperser and season, but most species transported as resting eggs by birds seem to have a wide tolerance to hatch under variable salinity conditions. These differences may largery influence the metacommunity dynamics of lake networks, and could be a key factor to consider in wetland conservation planning.

  8. 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.

  9. 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.

  10. Use of neutralized industrial residue to stabilize trace elements (Cu, Cd, Zn, As, Mo, and Cr) in marine dredged sediment from South-East of France.

    Science.gov (United States)

    Taneez, Mehwish; Marmier, Nicolas; Hurel, Charlotte

    2016-05-01

    Management of marine dredged sediments polluted with trace elements is prime issue in the French Mediterranean coast. The polluted sediments possess ecological threats to surrounding environment on land disposal. Therefore, stabilization of contaminants in multi-contaminated marine dredged sediment is a promising technique. Present study aimed to assess the effect of gypsum neutralized bauxaline(®) (bauxite residue) to decrease the availability of pollutants and inherent toxicity of marine dredged sediment. Bauxaline(®), (alumia industry waste) contains high content of iron oxide but its high alkalinity makes it not suitable for the stabilization of all trace elements from multi-contaminated dredged sediments. In this study, neutralized bauxaline(®) was prepared by mixing bauxaline(®) with 5% of plaster. Experiments were carried out for 3 months to study the effect of 5% and 20% amendment rate on the availability of Cu, Cd, Zn, As, Mo, and Cr. Trace elements concentration, pH, EC and dissolved organic carbon were measured in all leachates. Toxicity of leachates was assessed against marine rotifers Brachionus plicatilis. The Results showed that both treatments have immobilization capacity against different pollutants. Significant stabilization of contaminants (Cu, Cd, Zn) was achieved with 20% application rate whereas As, Mo, and Cr were slightly stabilized. Toxicity results revealed that leachates collected from treated sediment were less toxic than the control sediment. These results suggest that application of neutralized bauxaline(®) to dredged sediment is an effective approach to manage large quantities of dredged sediments as well as bauxite residue itself.

  11. Hatchery production of the clownfish Amphiprion nigripes at Agatti Island, Lakshadweep, India.

    Science.gov (United States)

    Kumar, T T Ajith; Gopi, M; Dhaneesh, K V; Vinoth, R; Ghosh, S; Balasubramanian, T; Shunmugaraj, T

    2012-05-01

    Healthy individuals of matured clownfish, Amphiprion nigripes and sea anemone, Heteractis magnifica were collected from the Agatti island lagoon by snorkeling. During 'conditioning' for 3 months, pair formation occurred and the same were transferred to rectangular fiber glass spawning tanks of 10001 capacity. Suitable water quality parameters were maintained. The fishes were fed with tuna eggs, boiled clam meat, squid, octopus and trash fish thrice in a day. Reproductive behaviour and embryonic development were documented. Spawning took place in between 0900 - 1100 hr and hatched-out occurs, after sunset following an incubation period of 8-9 days. Size of the newly laid egg was 2.0-2.2 mm in length and 1.0-1.2 mm in width. The larval rearing tanks were maintained with UV-treated water and followed the optimal physico-chemical parameters as in the parent tanks. The different light regimes and diets were used for the successful larval rearing. The maximum larval survival (61%) was achieved at the photoperiod of 24 L/0D. Within 15-17 days, the larvae metamorphosed and took up parent colouration and comparatively high growth rate was observed when fed on algae enriched rotifer than those with poly unsaturated fatty acid (PUFA).

  12. 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.  

  13. Composition and abundance of zooplankton in the limnetic zone of seven reservoirs of the Paranapanema River, Brazil

    Directory of Open Access Journals (Sweden)

    E. V. SAMPAIO

    Full Text Available The species composition and abundance of the zooplankton community of seven reservoirs of the Paranapanema River, located between 22º37'-23º11'S and 48º55'-50º32'W, were analysed over four periods, in the year of 1979. The zooplankton community was composed of 76 species of Rotifera, 26 species of Cladocera and 7 species of Copepoda. For a large part of the period under study the Rotifera were dominant, followed by Copepoda. The Piraju and Salto Grande reservoirs, which occupy intermediate positions in the cascade of reservoirs, were richest in species, most of them belonging to Rotifera and Cladocera. In the reservoirs Rio Pari and Rio Novo, lateral to the cascade of reservoirs, a lower species richness was observed, although higher densities of organisms were found than in the other reservoirs located in the main river body. Different rotifer species occurred in succession, being abundant in different periods, with no defined pattern. Among the copepods, Thermocyclops decipiens predominated in the majority of the reservoirs. Ceriodaphnia cornuta was the most abundant cladoceran in the intermediate reservoirs of the cascade, and Daphnia gessneri, Bosminopsis deitersi and Moina minuta, in the reservoirs lateral to the cascade. The most frequent zooplankton species were Notodiaptomus conifer, Thermocyclops decipiens, Ceriodaphnia cornuta cornuta and C. cornuta rigaudi, Daphnia gessneri, Bosmina hagmanni, Keratella cochlearis and Polyarthra vulgaris. Some relationships were found between the trophic state of the reservoirs and the zooplankton community.

  14. 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.

  15. 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

  16. ENVIRONMENTAL STUDY OF THE SEASONAL SUCCESSION OF MESOZOOPLANKTON IN A BRACKISH WATER ODRA RIVER ESTUARY DURING 2003–2005

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    Juliusz C. Chojnacki

    2013-04-01

    Full Text Available The entire estuary water is dominated by the discharge of the River Odra into the Szczecin Lagoon. The water body is brackish and the salinity in the central part ranges 0.5 and 2 PSU. The Lagoon has a long eutrophication history; usually, two phytoplankton biomass peaks are observed: Diatoms in spring and blue-green algae in summer. The recent data on zooplankton is limited. Rotifers and Cladocerans supply the bulk of the zooplankton biomass. The ichtiofauna is composed of fresh and brackish water, migratory and marine species. Zooplankton and water samples were collected during 2003–2005. The results suggest that during 10 season’s climate in Odra River estuary, Cladocera were the dominant group, large impact on the density of mesozooplankton were: Daphnia cucullata and Daphnia longispina, Copepoda played a lesser role in the Odra River estuary than Cladocera. Biomass of mesozooplankton from the Lagoon was significantly higher compared with the biomass of mesozooplankton from Odra River estuary, which could be related to a greater inflow of nutrients into the Lagoon and the increased growth of phytoplankton, which forms an excellent first stage food web for herbivorous and carnivorous zooplankton, and fish and consequently cormorants.

  17. Community and ecosystem responses to a pulsed pesticide disturbance in freshwater ecosystems.

    Science.gov (United States)

    Downing, Amy L; DeVanna, Kristen M; Rubeck-Schurtz, C Nichole; Tuhela, Laura; Grunkemeyer, Heather

    2008-08-01

    Pesticides have been shown to be detrimental to key groups of freshwater organisms including cladocerans, odonates, and amphibians. However, less is known about the response of freshwater communities and ecosystems to pesticide disturbances as they occur in nature. Using outdoor aquatic mesocosms, we assembled identical and diverse replicate freshwater plankton food webs obtained from an adjacent pond. We established three pesticide treatments consisting of pulses of a common pesticide Sevin with the active ingredient carbaryl, at concentrations of 0.1, 1 and 20 microg carbaryl/ml, and a pesticide-free control treatment. We monitored the response of microbial, phytoplankton, and zooplankton communities in addition to oxygen concentrations. Carbaryl concentrations peaked shortly after Sevin application and degraded quickly and treatment differences were undetectable after 30 days. Zooplankton richness, diversity, abundance, and oxygen concentrations all decreased in pulsed treatments, while phytoplankton and microbial abundance increased. Zooplankton composition in the high pesticide treatment consisted primarily of rotifers as compared to dominance by copepods in the other three treatments. While many of the community and ecosystem properties showed signs of recovery within 40 days after the pulsed pesticide disturbance, important and significant differences remained in the microbial, phytoplankton and zooplankton communities after the pesticide degraded.

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

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    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.

  19. Ecotoxicological effects of sediments from Mar Piccolo, South Italy: toxicity testing with organisms from different trophic levels.

    Science.gov (United States)

    Costa, Elisa; Piazza, Veronica; Gambardella, Chiara; Moresco, Roberto; Prato, Ermelinda; Biandolino, Francesca; Cassin, Daniele; Botter, Margherita; Maurizio, Daniela; D'Adamo, Raffaele; Fabbrocini, Adele; Faimali, Marco; Garaventa, Francesca

    2016-07-01

    The Mar Piccolo of Taranto (Ionian Sea, Southern Italy) is a semi-enclosed and strongly polluted basin. For decades, it has been subjected to different anthropogenic impacts. These stressors caused severe sediments contamination with high concentration of different pollutants (PAHs, PCB, heavy metals). In order to assess the current status of sediments contamination, an ecotoxicological investigation combined with chemical analysis (heavy metals, PAH, and PCB) has been performed. In order to derive ecologically relevant conclusions, a multiorganisms and multiend-points approach has been applied, exposing organisms from different trophic levels to elutriate and whole sediment. The battery of bioassays consists of a microalgal growth inhibition test (Dunaliella tertiolecta), acute and sublethal assays (end-points: mortality, immobilization and swimming speed alteration) on crustaceans larvae and juveniles, and rotifers (Amphibalanus amphitrite, Artemia salina, Corophium insidiosum and Brachionus plicatilis), and embryotoxicity test on echinoderms (Paracentrotus lividus). Considering the high levels of sediment contamination highlighted from chemical analysis, an unexpected very low toxic effect was observed, even considering the sublethal end-point (larval swimming speed alteration). The results of this study suggest a very complex contaminants dynamic in the Mar Piccolo sediments that, despite a strong level of contamination, seems to not affect in a proportional manner the biological compartment.

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

    Directory of Open Access Journals (Sweden)

    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.

  1. PROFIL PEMIJAHAN DAN PERKEMBANGAN MORFOLOGI LARVA DAN YUWANA IKAN CLOWN HITAM (Amphiprion percula

    Directory of Open Access Journals (Sweden)

    Daniar Kusumawati

    2016-11-01

    Full Text Available Amphiprion percula (ikan clown hitam atau clown Biak merupakan salah satu spesies ikan hias laut yang umumnya ditangkap untuk tujuan komersial. Di samping itu, indikasi menurunnya jumlah ikan clown hitam disebabkan oleh kematian secara alami di alam sebesar 75% akibat tingkat agresivitas ikan clown hitam dalam mempertahankan wilayahnya. Tujuan penelitian ini adalah untuk mengetahui profil pemijahan dan perkembangan morfologi larva dan yuwana ikan clown hitam. 10 pasang koleksi induk diperoleh dari Biak. Pengamatan dilakukan selama 1 tahun yang meliputi pengamatan reproduksi biologis dan aspek morfologi dan perkembangan larva dan yuwana ikan clown hitam. Berdasarkan pengamatan diketahui bahwa 70% dari populasi induk ikan clown hitam telah berhasil bertelur dengan periode pemijahan 9-30 hari. Jumlah produksi telur yang diperoleh 25 hingga 2.244 butir. Jumlah telur dengan bobot induk betina berkorelasi positif. Masa inkubasi telur terjadi selama 6 hingga 7 hari. Sesaat setelah menetas, larva (D0 dapat mengkonsumsi rotifer. Artemia dan pakan pelet yang diberikan mulai dari D6 dan D17. Periode perkembangan larva sangat singkat yaitu 17 hari. Selama pengamatan ikan clown hitam menunjukkan pertumbuhan yang relatif lambat

  2. Correspondence between zooplankton assemblages and the Estuary Environment Classification system

    Science.gov (United States)

    Lucena-Moya, Paloma; Duggan, Ian C.

    2017-01-01

    We tested whether variability in zooplankton assemblages was consistent with the categories of estuarine environments proposed by the 'Estuary Environment Classification' system (EEC) (Hume et al., 2007) across a variety of North Island, New Zealand, estuaries. The EEC classifies estuaries in to eight categories (A to F) based primarily on a combination of three abiotic controlling factors: ocean forcing, river forcing and basin morphometry. Additionally, we tested whether Remane's curve, which predicts higher diversities of benthic macrofauna and high and low salinities, can be applied to zooplankton assemblages. We focused on three of the eight EEC categories (B, D and F), which covered the range of estuaries with river inputs dominating (B) to ocean influence dominating (F). Additionally, we included samples from river (FW) and sea (MW) to encompass the entire salinity range. Zooplankton assemblages varied across the categories examined in accordance with a salinity gradient predicted by the EEC. Three groups of zooplankton were distinguishable: the first formed by the most freshwater categories, FW and B, and dominated by rotifers (primarily Bdelloidea) and estuarine copepods (Gladioferans pectinatus), a second group formed by categories D and F, of intermediate salinity, dominated by copepods (Euterpina acutifrons), and a final group including the purely marine category MW and dominated also by E. acutifrons along with other marine taxa. Zooplankton diversity responded to the salinity gradient in a manner expected from Remane's curve. The results of this study support others which have shown salinity to be the main factor driving zooplankton community composition and diversity.

  3. Large-scale utilization of water hyacinth for nutrient removal in Lake Dianchi in China: the effects on the water quality, macrozoobenthos and zooplankton.

    Science.gov (United States)

    Wang, Zhi; Zhang, Zhiyong; Zhang, Junqian; Zhang, Yingying; Liu, Haiqing; Yan, Shaohua

    2012-11-01

    An ecological engineering project using water hyacinth for nutrient removal was performed in Baishan Bay of a large shallow eutrophic lake, Lake Dianchi in China. In the present study, a systematic survey of water quality, macrozoobenthos and zooplankton inside (IWH), around (AWH) and far away (FWH) water hyacinth mats was conducted in Baishan Bay from August to October 2010. The results showed that the water quality significantly improved at AWH area. Concentrations of nitrogen and phosphorus were lower and transparency was higher at AWH area than those in IWH and FWH areas. Total densities, dominant species densities, and biodiversity indexes of macrozoobenthos and cladocerans as well as copepods did not differ (P>0.05) among each other in all three areas. It was significantly (P<0.05) different for those of rotifers at IWH area compared to those in AWH and FWH areas. The results might suggest a tremendous potential for the utilization of water hyacinth in the eutrophic lake like Lake Dianchi for nutrients removal.

  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. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Ecogenomics of Zooplankton Community Reveals Ecological Threshold of Ammonia Nitrogen.

    Science.gov (United States)

    Yang, Jianghua; Zhang, Xiaowei; Xie, Yuwei; Song, Chao; Sun, Jingying; Zhang, Yong; Giesy, John P; Yu, Hongxia

    2017-02-23

    Communities of zooplankton can be adversely affected by contamination resulting from human activities. Yet understanding the influence of water quality on zooplankton under field-conditions is hindered by traditional labor-intensive approaches that are prone to incomplete or uncertain taxonomic determinations. Here, for the first time, an eco-genomic approach, based on genetic diversity in the mitochondrial cytochrome c oxidase I (COI) region of DNA of zooplankton was used to develop a site-specific, water quality criterion (WQC) for ammonia (NH3). Ammonia has been recognized as a primary stressor in the catchment of the large, eutrophic Tai Lake, China. Nutrients, especially NH3 and nitrite (NO3(-)) had more significant effects on structure of the zooplankton community than did other environmental factors. Abundances of rotifers increased along a gradient of increasing concentrations of total ammonia nitrogen (TAN), while abundances of copepods and cladocera decreased. A novel, rapid, species sensitivity distribution (SSD) approach based on operational taxonomic units (OTUs) was established to develop a WQC for NH3. The WQC based on OTUs was consistent with the WQC based on the traditional morphology taxonomy approach. This genetics-based SSD approach could be a useful tool for monitoring for status and trends in species composition and deriving ecological criteria and an efficient biomonitoring tool to protect local aquatic ecosystems in virtually any aquatic ecosystem.

  11. 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.

  12. 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.

  13. Comparative studies on storage cells in tardigrades during starvation and anhydrobiosis

    Directory of Open Access Journals (Sweden)

    Andy REUNER, Steffen HENGHERR, Franz Brümmer, Ralph O. SCHILL

    2010-04-01

    Full Text Available The impact of starvation and anhydrobiosis on the number and size of the storage cells in the tardigrade species Milnesium tardigradum, Paramacrobiotus tonollii and Macrobiotus sapiens was investigated to gain more insight on the energetic side of anhydrobiosis. Storage cells are free floating cells within the body cavity of tardigrades and are presumed to store and release energy in form of glycogen, protein and fat to maintain a constant nutrient regime for the other tissues. The body size of the animals was not correlated with the size of the storage cells, however, M. tardigradum the largest species analysed also had the largest storage cells. A reduction in the size of the storage cells is apparent in all three species after seven days of starvation. A seven-day period of anhydrobiosis leads to a decrease in cell size in M. tardigradum but not in P. tonollii and M. sapiens. Although M. sapiens was raised on green algae, and M. tardigradum and P. tonollii were fed with rotifers and nematodes this difference in nourishment was not reflected in the response of the storage cells to anhydrobiosis [Current Zoology 56 (2: 259–263, 2010].

  14. 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.

  15. Bioremediation of petroleum hydrocarbons in soil: Activated sludge treatability study

    Energy Technology Data Exchange (ETDEWEB)

    Rue-Van Es, J.E. La.

    1993-05-01

    Batch activated sludge treatability studies utilizing petroleum hydrocarbon contaminated soils (diesel oil and leaded gasoline) were conducted to determine: initial indigenous biological activity in hydrocarbon-contaminated soils; limiting factors of microbiological growth by investigating nutrient addition, chemical emulsifiers, and co-substrate; acclimation of indigenous population of microorganisms to utilize hydrocarbons as sole carbon source; and temperature effects. Soil samples were taken from three different contaminated sites and sequencing batch reactors were run. Substrate (diesel fuel) and nutrient were added as determined by laboratory analysis of orthophosphate, ammonia nitrogen, chemical oxygen demand, and total organic carbon. Substrate was made available to the bacterial mass by experimenting with four different chemical emulsifiers. Indigenous microorganisms capable of biotransforming hydrocarbons seem to be present in all the contaminated soil samples received from all sites. Microscopic analysis revealed no visible activity at the beginning of the study and presence of flagellated protozoa, paramecium, rotifers, and nematodes at the end of the year. Nutrient requirements and the limiting factors in microorganism growth were determined for each site. An emulsifier was initially necessary to make the substrate available to the microbial population. Decreases in removal were found with lowered temperature. Removal efficiencies ranged from 50-90%. 95 refs., 11 figs., 13 tabs.

  16. Desiccation tolerance in the tardigrade Richtersius coronifer relies on muscle mediated structural reorganization.

    Directory of Open Access Journals (Sweden)

    Kenneth Agerlin Halberg

    Full Text Available Life unfolds within a framework of constraining abiotic factors, yet some organisms are adapted to handle large fluctuations in physical and chemical parameters. Tardigrades are microscopic ecdysozoans well known for their ability to endure hostile conditions, such as complete desiccation--a phenomenon called anhydrobiosis. During dehydration, anhydrobiotic animals undergo a series of anatomical changes. Whether this reorganization is an essential regulated event mediated by active controlled processes, or merely a passive result of the dehydration process, has not been clearly determined. Here, we investigate parameters pivotal to the formation of the so-called "tun", a state that in tardigrades and rotifers marks the entrance into anhydrobiosis. Estimation of body volume in the eutardigrade Richtersius coronifer reveals an 87 % reduction in volume from the hydrated active state to the dehydrated tun state, underlining the structural stress associated with entering anhydrobiosis. Survival experiments with pharmacological inhibitors of mitochondrial energy production and muscle contractions show that i mitochondrial energy production is a prerequisite for surviving desiccation, ii uncoupling the mitochondria abolishes tun formation, and iii inhibiting the musculature impairs the ability to form viable tuns. We moreover provide a comparative analysis of the structural changes involved in tun formation, using a combination of cytochemistry, confocal laser scanning microscopy and 3D reconstructions as well as scanning electron microscopy. Our data reveal that the musculature mediates a structural reorganization vital for anhydrobiotic survival, and furthermore that maintaining structural integrity is essential for resumption of life following rehydration.

  17. Experimental evidence for strong stabilizing forces at high functional diversity of aquatic microbial communities.

    Science.gov (United States)

    Carrara, Francesco; Giometto, Andrea; Seymour, Mathew; Rinaldo, Andrea; Altermatt, Florian

    2015-05-01

    Unveiling the mechanisms that promote coexistence in biological communities is a fundamental problem in ecology. Stable coexistence of many species is commonly observed in natural communities. Most of these natural communities, however, are composed of species from multiple trophic and functional groups, while theory and experiments on coexistence have been focusing on functionally similar species. Here, we investigated how functional diversity affects the stability of species coexistence and productivity in multispecies communities by characterizing experimentally all pairwise species interactions in a pool of 11 species of eukaryotes (10 protists and one rotifer) belonging to three different functional groups. Species within the same functional group showed stronger competitive interactions compared to among-functional group interactions. This often led to competitive exclusion between species that had higher functional relatedness, but only at low levels of species richness. Communities with higher functional diversity resulted in increased species coexistence and community biomass production. Our experimental findings and the results of a stochastic model tailored to the experimental interaction matrix suggest the emergence of strong stabilizing forces when species from different functional groups interact in a homogeneous environment. By combining theoretical analysis with experiments we could also disentangle the relationship between species richness and functional diversity, showing that functional diversity per se is a crucial driver of productivity and stability in multispecies community.

  18. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  20. 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.

  1. 竹丝生物膜反应器修复景观水体的研究%Remediation of Landscape Water Using Biofilm Reactorwith Bamboo Filamentous Biocarrier

    Institute of Scientific and Technical Information of China (English)

    苏刘选; 陈建中; 曹文平; 宋延芝

    2010-01-01

    利用竹丝生物膜反应器处理低污染景观水体,研究了反应器对原水浊度、氨氮、高锰酸盐指数的去除效果以及生物相的变化情况等.试验结果表明:竹丝生物膜反应器对景观水体中的浊度、氨氮和高锰酸盐指数的去除率分别为19.99%~100%、15.9%~59%和10.60%~74.34%. 同时系统内出现了丰富的生物相如钟虫(Vorticella)、草履虫(Paramoecium)、轮虫(Rotifer)、喇叭虫(Stentor)、豆形虫(Colpidium)等,且活性良好,说明竹丝生物膜反应器很适合低污染景观水体的修复.

  2. 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..

  3. 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.

  4. 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.

  5. Diurnal variation of zooplankton in Bhoj Wetland, Bhopal, India

    Directory of Open Access Journals (Sweden)

    Najeeb Ahmad Bhat

    2013-09-01

    Full Text Available The diurnal dynamics of the vertical distribution of zooplankton was studied in Bhoj Wetland, Bhopal. Vertical distribution of the zooplankton community in general showed a clear diurnal variation in the water column of a typical stratified lake. Zooplankton concentration was found to be high at the surface layer during night hours with peak abundance around the middle of the night and another peak was observed just before sunrise, followed by a rapid nadir after sunrise. Zooplankton can offset the loss of daytime foraging opportunity by moving up into the water column to graze at night, when predation by visual predators is greatly reduced and it can be also attributed to light intensity which is responsible for vertical migration during the twenty four hour cycles. Among different classes, cladocerans and the copepod showed nocturnal migration conversely rotifers, had a relatively uniform distribution throughout the water column Out of the twenty three species, Bosmina species and Cyclops species ascended at night and descended during day hours, however, Keratella cochlearis showed uniformity in distribution throughout the water column during the study.

  6. 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).

  7. 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.

  8. 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.

  9. 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.

  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. The Physico-chemistry and Plankton Diversity of Awba Reservoir University of Ibadan, Ibadan Nigeria

    Directory of Open Access Journals (Sweden)

    I.J. Anago

    2013-11-01

    Full Text Available The physico-chemical parameters and plankton diversity of Awba Reservoir, University of Ibadan was sampled from April to July, 2011. Surface water samples were collected for physico-chemical parameters. Values of the physico-chemical parameters observed ranged as follows: water temperature, 24-26.5°C; air temperature, 22-23. °C; transparency, 0.2-0.4 m; pH, 7.3-8.4; total dissolved solids, 143.8-159.5 mg/L; conductivity, 290.8-391.5 &mumhos/cm; salinity, 0.11-0.19%; dissolved oxygen, 0.7-1.8 mg/L and alkalinity, 0.8-1.7 mg CaCO3/L. Thirty six taxa of plankton were encountered. Phytoplankton consisted of five families namely; Cyanophyceae, Chlorophyceae, Euglenophyceae, Bacillariophyceae and Dinophyceae. Three groups of zooplankton encountered were copepods, cladocerans and rotifers. The presence of pollution indicator species such as, Microcystis, Phacus, Oscillatoria, Surirella Closterium, Aphanocapsa, Anabeana and Euglena show that the Reservoir is likely polluted.

  12. The influence of a river plume on the sea-ice meiofauna in south-eastern Hudson Bay

    Science.gov (United States)

    Grainger, E. H.

    1988-08-01

    Outflow from the Great Whale River produces a substantial freshwater layer (plume) beneath the winter ice cover and above water of higher salinity in south-eastern Hudson Bay. In 1983, samples of the lower-ice fauna and of zooplankton beneath the ice, were taken within, below and beyond the offshore reach of the plume. Nematodes accounted for the highest numbers (mean of 1956 1 1in the lower 3 cm of ice), and copepods, mainly Harpacticus and Halectinosoma with fewer Tisbe and Oithona, for the greatest biomass. All ice-inhabiting taxa were also found in the water below the ice, but many zooplankters occurring immediately beneath the ice did not form part of the ice fauna. No major qualitative differences were evident between the ice communities existing above the plume and offshore from it, but quantitative distinctions were readily apparent. Animals were consistently more concentrated (by 2-3 orders of magnitude) in the lower 3 cm of the ice than in the water immediately below, both over the plume and outside it. Except for the dominant rotifers in the plume, the concentration of zooplankton there was only 10% of that found in the surface water outside the plume. The river plume exerts a strong influence over the quantity of the fauna in the sea ice immediately above it. Changes in location and extent of the plume therefore may have an important effect on the food chain based in the sea ice.

  13. TEKNOLOGI PEMELIHARAAN LARVA KERAPU SUNU (Plectropomus leopardus SECARA MASSAL

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    Titiek Aslianti

    2016-12-01

    Seed production technology of leopard coral trout, Plectropomus leopardus by improving hatchery management had been conducted in order to increase survival rate and to produce seed continuity. The initial feeding can successfully support in larval rearing. Feed organism as rotifer, trochophore gonad, egg yolk emulsion, and artificial feed emulsion, had been used as an initial feed. The twelve of concrete tanks with 6 m3 capacity were stocked with coral trout eggs at density 100,000—150,000 eggs/tank. Artemia nauplii, artificial feed, and mysid as feed, start on larvae D20 up to juvenile stage (D45. Growth rate and survival rate were observed and calculated when the experiment was terminated. The data was analyzed by descriptive. Nutrition value of food was analyzed by proximate and fatty acid composition. The others parameters such as deformity and water quality were observed. The result showed that artificial feed emulsion and egg yolk emulsion as an initial feeding can be improve the growth rate and increase survival rate of larvae. The range of total length, body weight and survival rate of the seed i.e. 1.95—2.85 cm; 0.64—0.73 g, and 0.25%— 3.97% with the daily growth rate 3,9%—4,22%, respectively. No back bone deformity in the seed, that is 21—23 segments with interspaces of segments 0.030—0.036 mm.

  14. 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.

  15. 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.

  16. Relationship of atmospheric pollution characterized by gas (NO2) and particles (PM10) to microbial communities living in bryophytes at three differently polluted sites (rural, urban, and industrial).

    Science.gov (United States)

    Meyer, Caroline; Gilbert, Daniel; Gaudry, André; Franchi, Marielle; Nguyen, Hung Viet; Fabure, Juliette; Bernard, Nadine

    2010-02-01

    Atmospheric pollution has become a major problem for modern societies owing to its fatal effects on both human health and ecosystems. We studied the relationships of nitrogen dioxide atmospheric pollution and metal trace elements contained in atmospheric particles which were accumulated in bryophytes to microbial communities of bryophytes at three differently polluted sites in France (rural, urban, and industrial) over an 8-month period. The analysis of bryophytes showed an accumulation of Cr and Fe at the rural site; Cr, Fe, Zn, Cu, Al, and Pb at the urban site; and Fe, Cr, Pb, Al, Sr, Cu, and Zn at the industrial site. During this study, the structure of the microbial communities which is characterized by biomasses of microbial groups evolved differently according to the site. Microalgae, bacteria, rotifers, and testate amoebae biomasses were significantly higher in the rural site. Cyanobacteria biomass was significantly higher at the industrial site. Fungal and ciliate biomasses were significantly higher at the urban and industrial sites for the winter period and higher at the rural site for the spring period. The redundancy analysis showed that the physico-chemical variables ([NO(2)], relative humidity, temperature, and site) and the trace elements which were accumulated in bryophytes ([Cu], [Sr], [Pb]) explained 69.3% of the variance in the microbial community data. Moreover, our results suggest that microbial communities are potential biomonitors of atmospheric pollution. Further research is needed to understand the causal relationship underlined by the observed patterns.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. 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.

  19. Experiments with small animals in BIOLAB and EMCS on the international space station

    Science.gov (United States)

    Brinckmann, E.; Schiller, P.

    Two ESA facilities will be available for animal research and other biological experiments on the International Space Station: the European Modular Cultivation System (EMCS) in the US Lab "Destiny" and BIOLAB in the European "Columbus" Laboratory. Both facilities use standard Experiment Containers, mounted on two centrifuge rotors allowing either research in microgravity or acceleration studies with variable g-levels from 0.001 to 2.0x g. Standard interface plates provide each container with power and data lines, gas supply (controlled CO 2, O 2 concentration and relative humidity), and -for EMCS only- connectors to fresh and waste water reservoirs. The experiment hardware inside the containers will be developed by the user, but ESA conducted a feasibility study for several kinds of Experiment Support Equipment with potential use for research on small animals: design concepts for experiments with insects, with aquatic organisms like rotifers and nematodes, and with small aquatic animals (sea urchin larvae, tadpoles, fish youngsters) are described in detail in this presentation. Also ESA's initial steps to support experiments with rodents on the Space Station are presented.

  20. "We learned how to live in Pallanza"

    Directory of Open Access Journals (Sweden)

    John T. LEHMAN

    2000-02-01

    Full Text Available After months of paralysis from injuries sustained in an automobile accident, W. Thomas Edmondson died in Seattle during January. Known as "Tommy" to one and all, in keeping with his nickname he retained a youthful and alert mind until the end. Tommy Edmondson will remain forever linked with the field of limnology that he loved. It is easy to recount his growth and accomplishments in science, starting from his first glimpse of a rotifer through the microscope he received as a gift at the age of 12. Those fortunate to have visited with him in his Seattle office can recall fondly the sight of a desk and chair piled high with "study graphs" and various works in progress which he would graciously set aside in welcome and eager interest for the visitor. But by his own reckoning, Tommy declared that there was a moment in time that was transformational in spirit and mind. That was the period in 1959 and 1960 during which he took sabbatical leave at the great limnological centers in Windermere, Uppsala, and Pallanza. Thirty five years later, he recalled the events with earnest delight, but his fondest memories were reserved for the town on the shore of Lago Maggiore. "We learned how to live in Pallanza," was his assessment of the time.

  1. PERKEMBANGAN AWAL LARVA KERAPU KERTANG (Epinephelus lanceolatus

    Directory of Open Access Journals (Sweden)

    Philip Teguh Imanto

    2016-11-01

    Full Text Available Observasi pada larva kerapu kertang (E. lanceolatus dilaksanakan di Balai Besar Riset Perikanan Budidaya Laut (BBRPBL, Gondol-Bali, untuk mengumpulkan informasi dasar tentang perkembangan awal morfologi larva yang penting untuk menunjang keberhasilan pembenihannya. Larva berasal dari telur hasil pemijahan yang dirangsang dengan hormon (di Taiwan dan ditransportasikan segera setelah menetas (D-0 melalui transportasi udara ke laboratotium pembenihan BBRPBL, Gondol. Pengamatan dilakukan dengan memanfaatkan fasilitas tangki 500 L dengan sistem air resirkulasi. Dari data yang dihimpun diketahui bahwa rata-rata panjang total larva (D-1 2,48 mm; D-8 3,17 mm; dan tumbuh dengan cepat mencapai 10,79 mm pada D-19. Kuning telur larva yang berumur sehari (D-1 rata-rata bervolume 150,3 x 10-4 mm3 dan pada hari ketiga terserap 42,61% dan habis pada hari keempat (D-4. Butir minyak larva D-1 sebesar 41,9 x 10-4 mm3 dan masih tersisa sebesar 0,34 x 10-4 mm3 sampai dengan D-6. Mulut larva diperhitungkan sudah mencapai lebar sebesar 200 μm pada D-2. dan mampu untuk memangsa rotifer sejalan dengan pigmentasi mata yang mulai terjadi pada D-2 dan sempurna pada D-3. Dari analisis pertumbuhan terjadi titik belok (flexion point pada D-8 dan setelah itu terjadi kurva pertumbuhan yang cepat y= 0,6747x-2,5508. Berdasarkan hasil observasi tersebut maka pemberian pakan awal untuk larva kerapu kertang sudah bisa diberikan pada D-2 akhir (sore, pada D-8 komposisi pakan alami sudah harus diubah dengan memberikan pakan yang lebih besar dan bernutrisi tinggi. Observation on early development of E. lanceolatus larvae have been conducted in laboratory condition at Gondol Research Institute for Mariculture (GRIM Bali; the purpose was to gain basic data mainly on the larval development stage to support both larval rearing and aquaculture technique of this species. The larvae from egg were produced by induced spawning technique and transported on D-0 to GRIM. Observation have been

  2. 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

  3. 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

  4. 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

  5. The consequences of facultative sex in a prey adapting to predation.

    Science.gov (United States)

    Koch, H; Becks, L

    2017-01-01

    A species reproductive mode, along with its associated costs and benefits, can play a significant role in its evolution and survival. Facultative sexuality, being able to reproduce both sexually and asexually, has been deemed evolutionary favourable as the benefits of either mode may be fully realized. In fact, many studies have focused on identifying the benefits of sex and/or the forces selecting for increased rates of sex using facultative sexual species. The costs of either mode, however, can also have a profound impact on a population's evolutionary trajectory. Here, we used experimental evolution and fitness assays to investigate the consequences of facultative sexuality in prey adapting to predation. Specifically, we compared the adaptive response of algal prey populations exposed to constant rotifer predation and which had alternating cycles of asexual and sexual reproduction where sexual episodes were either facultative (sexual and asexual progeny simultaneously propagated) or obligate (only sexual progeny propagated). We found that prey populations with facultative sexual episodes reached a lower final relative fitness and suffered a greater trade-off in traits under selection, that is defence and competitive ability, as compared to prey populations with obligate sexual episodes. Our results suggest that costs associated with sexual reproduction (germination time) and asexual reproduction (selection interference) were amplified in the facultative sexual prey populations, leading to a reduction in the net advantage of sexuality. Additionally, we found evidence that the cost of sex was reduced in the obligate sexual prey populations because increased selection for sex was observed via the spontaneous production of sexual cells. These results show that certain costs associated with facultative sexuality can affect an organism's evolutionary trajectory.

  6. 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

    Institute of Scientific and Technical Information of China (English)

    LIU Guangxing; XU Donghui

    2009-01-01

    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 (P<0.01). Three live organisms were used for raising larvae and juveniles ofParalichthys olivaceus respectively for 15 and 10 d. Then the growth, survival and fatty acid composition of the larvae and juveniles were investigated. The results showed that the larvae and juveniles fed with copepods (S. poplesia) had significantly higher growth rate than thosc fed with the other two organisms (P<0.01). The survival of the flounder larvae fed with copepods was significantly higher than that of the others (P<0.01), and the survival of the juvenile fish fed with copepods was higher than that fed with Artemia (P<0.05). The contents of three types of HUFAs (DHA, 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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

    2015-01-01

    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

  11. 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 (liquid fertilizer as compared to the other diets. The growth rates of M. macrocopa ranged from 0.1 to 0.38/d, and were highest with diets of C. vulgaris cultured in Bold medium and S. acutus cultured in fertilizer. Thus, regardless of the culture medium used, the growth rates of the evaluated zooplankton species were higher with Chlorella than with Scenedesmus. The peak population density was highest (2 800ind/mL) for A. fissa fed Chlorella that was cultured on liquid fertilizers, while B. rubens and M. macrocopa had peak abundances of 480 and 12ind/mL, respectively under similar conditions.

  12. Forest Management Intensity Affects Aquatic Communities in Artificial Tree Holes.

    Directory of Open Access Journals (Sweden)

    Jana S Petermann

    Full Text Available 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

  13. 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

  14. The stabilizing effects of genetic diversity on predator-prey dynamics.

    Science.gov (United States)

    Steiner, Christopher F; Masse, Jordan

    2013-01-01

    Heterogeneity among prey in their susceptibility to predation is a potentially important stabilizer of predator-prey interactions, reducing the magnitude of population oscillations and enhancing total prey population abundance. When microevolutionary responses of prey populations occur at time scales comparable to population dynamics, adaptive responses in prey defense can, in theory, stabilize predator-prey dynamics and reduce top-down effects on prey abundance. While experiments have tested these predictions, less explored are the consequences of the evolution of prey phenotypes that can persist in both vulnerable and invulnerable classes. We tested this experimentally using a laboratory aquatic system composed of the rotifer Brachionus calyciflorus as a predator and the prey Synura petersenii, a colony-forming alga that exhibits genetic variation in its propensity to form colonies and colony size (larger colonies are a defense against predators). Prey populations of either low initial genetic diversity and low adaptive capacity or high initial genetic diversity and high adaptive capacity were crossed with predator presence and absence. Dynamics measured over the last 127 days of the 167-day experiment revealed no effects of initial prey genetic diversity on the average abundance or temporal variability of predator populations. However, genetic diversity and predator presence/absence interactively affected prey population abundance and stability; diversity of prey had no effects in the absence of predators but stabilized dynamics and increased total prey abundance in the presence of predators. The size structure of the genetically diverse prey populations diverged from single strain populations in the presence of predators, showing increases in colony size and in the relative abundance of cells found in colonies. Our work sheds light on the adaptive value of colony formation and supports the general view that genetic diversity and intraspecific trait variation of

  15. The stabilizing effects of genetic diversity on predator-prey dynamics [v1; ref status: indexed, http://f1000r.es/9u

    Directory of Open Access Journals (Sweden)

    Christopher F Steiner

    2013-02-01

    Full Text Available Heterogeneity among prey in their susceptibility to predation is a potentially important stabilizer of predator-prey interactions, reducing the magnitude of population oscillations and enhancing total prey population abundance. When microevolutionary responses of prey populations occur at time scales comparable to population dynamics, adaptive responses in prey defense can, in theory, stabilize predator-prey dynamics and reduce top-down effects on prey abundance. While experiments have tested these predictions, less explored are the consequences of the evolution of prey phenotypes that can persist in both vulnerable and invulnerable classes. We tested this experimentally using a laboratory aquatic system composed of the rotifer Brachionus calyciflorus as a predator and the prey Synura petersenii, a colony-forming alga that exhibits genetic variation in its propensity to form colonies and colony size (larger colonies are a defense against predators. Prey populations of either low initial genetic diversity and low adaptive capacity or high initial genetic diversity and high adaptive capacity were crossed with predator presence and absence. Dynamics measured over the last 127 days of the 167-day experiment revealed no effects of initial prey genetic diversity on the average abundance or temporal variability of predator populations. However, genetic diversity and predator presence/absence interactively affected prey population abundance and stability; diversity of prey had no effects in the absence of predators but stabilized dynamics and increased total prey abundance in the presence of predators. The size structure of the genetically diverse prey populations diverged from single strain populations in the presence of predators, showing increases in colony size and in the relative abundance of cells found in colonies. Our work sheds light on the adaptive value of colony formation and supports the general view that genetic diversity and intraspecific

  16. 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

  17. 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.

  18. An integrated fish-plankton aquaculture system in brackish water.

    Science.gov (United States)

    Gilles, S; Fargier, L; Lazzaro, X; Baras, E; De Wilde, N; Drakidès, C; Amiel, C; Rispal, B; Blancheton, J-P

    2013-02-01

    Integrated Multi-Trophic Aquaculture takes advantage of the mutualism between some detritivorous fish and phytoplankton. The fish recycle nutrients by consuming live (and dead) algae and provide the inorganic carbon to fuel the growth of live algae. In the meanwhile, algae purify the water and generate the oxygen required by fishes. Such mechanism stabilizes the functioning of an artificially recycling ecosystem, as exemplified by combining the euryhaline tilapia Sarotherodon melanotheron heudelotii and the unicellular alga Chlorella sp. Feed addition in this ecosystem results in faster fish growth but also in an increase in phytoplankton biomass, which must be limited. In the prototype described here, the algal population control is exerted by herbivorous zooplankton growing in a separate pond connected in parallel to the fish-algae ecosystem. The zooplankton production is then consumed by tilapia, particularly by the fry and juveniles, when water is returned to the main circuit. Chlorella sp. and Brachionus plicatilis are two planktonic species that have spontaneously colonized the brackish water of the prototype, which was set-up in Senegal along the Atlantic Ocean shoreline. In our system, water was entirely recycled and only evaporation was compensated (1.5% volume/day). Sediment, which accumulated in the zooplankton pond, was the only trophic cul-de-sac. The system was temporarily destabilized following an accidental rotifer invasion in the main circuit. This caused Chlorella disappearance and replacement by opportunist algae, not consumed by Brachionus. Following the entire consumption of the Brachionus population by tilapias, Chlorella predominated again. Our artificial ecosystem combining S. m. heudelotii, Chlorella and B. plicatilis thus appeared to be resilient. This farming system was operated over one year with a fish productivity of 1.85 kg/m2 per year during the cold season (January to April).

  19. 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。

  20. 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.

  1. The evolution of sex is favoured during adaptation to new environments.

    Science.gov (United States)

    Becks, Lutz; Agrawal, Aneil F

    2012-01-01

    Both theory and experiments have demonstrated that sex can facilitate adaptation, potentially yielding a group-level advantage to sex. However, it is unclear whether this process can help solve the more difficult problem of the maintenance of sex within populations. Using experimental populations of the facultatively sexual rotifer Brachionus calyciflorus, we show that rates of sex evolve to higher levels during adaptation but then decline as fitness plateaus. To assess the fitness consequences of genetic mixing, we directly compare the fitnesses of sexually and asexually derived genotypes that naturally occur in our experimental populations. Sexually derived genotypes are more fit than asexually derived genotypes when adaptive pressures are strong, but this pattern reverses as the pace of adaptation slows, matching the pattern of evolutionary change in the rate of sex. These fitness assays test the net effect of sex but cannot be used to disentangle whether selection on sex arises because highly sexual lineages become associated with different allele combinations or with different allele frequencies than less sexual lineages (i.e., "short-" or "long-term" effects, respectively). We infer which of these mechanisms provides an advantage to sex by performing additional manipulations to obtain fitness distributions of sexual and asexual progeny arrays from unbiased parents (rather than from naturally occurring, and thereby evolutionarily biased, parents). We find evidence that sex breaks down adaptive gene combinations, resulting in lower average fitness of sexual progeny (i.e., a short-term disadvantage to sex). As predicted by theory, the advantage to sex arises because sexually derived progeny are more variable in fitness, allowing for faster adaptation. This "long-term advantage" builds over multiple generations, eventually resulting in higher fitness of sexual types.

  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. Community patterns of the small riverine benthos within and between two contrasting glacier catchments.

    Science.gov (United States)

    Eisendle-Flöckner, Ursula; Jersabek, Christian D; Kirchmair, Martin; Hashold, Kerstin; Traunspurger, Walter

    2013-09-01

    Ongoing glacial retreat is expected to lead to numerous changes in glacier-fed rivers. This study documents the development of community composition of the hitherto widely neglected micro- and meiobenthos (MMB: bacteria, fungi, algae, protists, and meiofauna) in glacier rivers in response to the distinct habitat conditions driven by different stages of (de)glacierization. Our model is based on the glacier catchments of the Möll River (MC) and Kleinelendbach stream (KC), in the Austrian Alps, with 60% and 25% glacierization and glacier retreats of 403 and 26 m, respectively, since 1998. Analyses of overall catchment diversity and resemblance patterns showed that neither intense glacierization nor rapid deglacierization were predominant MMB determinants. This was ascribed to the specific environmental conditions at the MC, where the rapidly retreating Pasterze glacier has formed a harsh unstable proglacial, but also a benign floodplain area, with the former suppressing and the latter supporting the structural development of the MMB. Comparisons of similarly aged riverine habitats of the MC proglacial and the KC main channel further evidenced developmental suppression of the MMB (64 taxa) by the rapidly retreating MC glacier, unlike the moderate glacial retreat in the KC (130 taxa). Habitat conditions interacting with melt periods explained the differences in MMB resemblance patterns, which themselves differentially reflected the spatiotemporal habitat settings imposed by the different glacier activities. The varying glacial influences were represented by a glaciality index (GIm) based on water temperature, electrical conductivity, and stream bed stability. The taxonomic richness of nematodes, rotifers, algae, and diatoms was distinctly related to this index, as were most MMB abundances. However, the strongest relationships to the GIm were those of nematode abundances and maturity. Our observations highlight the intense response of the MMB to ongoing glacier retreat

  4. 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.

  5. Molecular Taxonomic Profiling of Bacterial Communities in a Gilthead Seabream (Sparus aurata) Hatchery

    Science.gov (United States)

    Califano, Gianmaria; Castanho, Sara; Soares, Florbela; Ribeiro, Laura; Cox, Cymon J.; Mata, Leonardo; Costa, Rodrigo

    2017-01-01

    As wild fish stocks decline worldwide, land-based fish rearing is likely to be of increasing relevance to feeding future human generations. Little is known about the structure and role of microbial communities in fish aquaculture, particularly at larval developmental stages where the fish microbiome develops and host animals are most susceptible to disease. We employed next-generation sequencing (NGS) of 16S rRNA gene reads amplified from total community DNA to reveal the structure of bacterial communities in a gilthead seabream (Sparus aurata) larviculture system. Early- (2 days after hatching) and late-stage (34 days after hatching) fish larvae presented remarkably divergent bacterial consortia, with the genera Pseudoalteromonas, Marinomonas, Acinetobacter, and Acidocella (besides several unclassified Alphaproteobacteria) dominating the former, and Actinobacillus, Streptococcus, Massilia, Paracoccus, and Pseudomonas being prevalent in the latter. A significant reduction in rearing-water bacterial diversity was observed during the larviculture trial, characterized by higher abundance of the Cryomorphaceae family (Bacteroidetes), known to populate microniches with high organic load, in late-stage rearing water in comparison with early-stage rearing-water. Furthermore, we observed the recruitment, into host tissues, of several bacterial phylotypes—including putative pathogens as well as mutualists—that were detected at negligible densities in rearing-water or in the live feed (i.e., rotifers and artemia). These results suggest that, besides host-driven selective forces, both the live feed and the surrounding rearing environment contribute to shaping the microbiome of farmed gilthead sea-bream larvae, and that a differential establishment of host-associated bacteria takes place during larval development. PMID:28261166

  6. 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.

  7. 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.

  8. 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.

  9. Direct and indirect effects of the glyphosate formulation Glifosato Atanor® on freshwater microbial communities.

    Science.gov (United States)

    Vera, María Solange; Di Fiori, Eugenia; Lagomarsino, Leonardo; Sinistro, Rodrigo; Escaray, Roberto; Iummato, María Mercedes; Juárez, Angela; Ríos de Molina, María del Carmen; Tell, Guillermo; Pizarro, Haydée

    2012-10-01

    Glyphosate-based formulations are among the most widely used herbicides in the world. The effect of the formulation Glifosato Atanor(®) on freshwater microbial communities (phytoplankton, bacterioplankton, periphyton and zooplankton) was assessed through a manipulative experiment using six small outdoor microcosms of small volume. Three of the microcosms were added with 3.5 mg l(-1) of glyphosate whereas the other three were left as controls without the herbicide. The treated microcosms showed a significant increase in total phosphorus, not fully explained by the glyphosate present in the Glifosato Atanor(®). Therefore, part of the phosphorus should have come from the surfactants of the formulation. The results showed significant direct and indirect effects of Glifosato Atanor(®) on the microbial communities. A single application of the herbicide caused a fast increase both in the abundance of bacterioplankton and planktonic picocyanobacteria and in chlorophyll a concentration in the water column. Although metabolic alterations related to oxidative stress were induced in the periphyton community, the herbicide favored its development, with a large contribution of filamentous algae typical of nutrient-rich systems, with shallow and calm waters. An indirect effect of the herbicide on the zooplankton was observed due to the increase in the abundance of the rotifer Lecane spp. as a consequence of the improved food availability given by picocyanobacteria and bacteria. The formulation affected directly a fraction of copepods as a target. It was concluded that the Glifosato Atanor(®) accelerates the deterioration of the water quality, especially when considering small-volume water systems.

  10. FEEDING INCIDENCE, GROWTH AND SURVIVAL RATE IN THE EARLY STAGE OF THE RED-SPOTTED GROUPER, Epinephelus akaara, IN RELATION TO TANK COLOR

    Directory of Open Access Journals (Sweden)

    Eri Setiadi

    2006-12-01

    Full Text Available The red-spotted grouper, Epinephelus akaara, is one of marine fish species targeted for mariculture in Japan. The artificial mass seedling production of these species has been largely successful. However, the survival is still unstable. The effect of tank colors on the feeding incidence, feeding proportion, growth and survival rates in the early stage of the red-spotted grouper were examined. The results showed the feeding incidence, feeding proportion, growth, and survival rates at different tank colors were highly significantly different (P<0.001. Post hoc multiple comparisons based on Tukey’s test showed significant differences (P<0.05 regarding feeding incidence between yellow (70.45% compared to white (55.83%, black (48.42%, green (41.67%, blue (35.17%, and red (32.50%. The highest feeding proportion (number of rotifer in the stomach/larvae was found at yellow (5.62, followed by white (2.47, black (1.97, green (1.92, blue (1.71, and red (1.28. The specific growth rate showed significant differences (P<0.05 were found at yellow (2.14% and white (1.84% compared to black (1.46%, green (1.20%, blue (1.15%, and red (1.13%. The survival rate at yellow color (1.22% was the highest, followed by white (1.09%, black (0.79%, green (0.57%, blue (0.38%, and red (0.37%. Yellow was suitable as tank wall color for rearing of red-spotted grouper larvae.

  11. Diel vertical migration of predators (planktivorous fish larvae and prey (zooplankton in a tropical lagoon

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    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.

  12. 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.

  13. Evolution of the AKH/corazonin/ACP/GnRH receptor superfamily and their ligands in the Protostomia.

    Science.gov (United States)

    Hauser, Frank; Grimmelikhuijzen, Cornelis J P

    2014-12-01

    In this review we trace the evolutionary connections between GnRH receptors from vertebrates and the receptors for adipokinetic hormone (AKH), AKH/corazonin-related peptide (ACP), and corazonin from arthropods. We conclude that these G protein-coupled receptors (GPCRs) are closely related and have a common evolutionary origin, which dates back to the split of Proto- and Deuterostomia, about 700 million years ago. We propose that in the protostomian lineage, the ancestral GnRH-like receptor gene duplicated as did its GnRH-like ligand gene, followed by diversification, leading to (i) a corazonin receptor gene and a corazonin-like ligand gene, and (ii) an AKH receptor gene and an AKH-like ligand gene in the Mollusca and Annelida. Subsequently, the AKH receptor and ligand genes duplicated once more, yielding the situation that we know from arthropods today, where three independent hormonal systems exist, signalling with AKH, ACP, and corazonin. Our model for the evolution of GnRH signaling in the Protostomia is a striking example of receptor-ligand co-evolution. This model has been developed using several bioinformatics tools (TBLASTN searches, phylogenetic tree analyses), which also helped us to annotate six novel AKH preprohormones and their corresponding AKH sequences from the following molluscs: the sea hare Aplysia californica (AKH sequence: pQIHFSPDWGTamide), the sea slug Tritonia diomedea (pQIHFSPGWEPamide), the fresh water snail Bithynia siamensis goniomphalos (pQIHFTPGWGSamide), the owl limpet Lottia gigantea (pQIHFSPTWGSamide), the oyster Crassostrea gigas (pQVSFSTNWGSamide), and the freshwater pearl mussel Hyriopsis cumingii (pQISFSTNWGSamide). We also found AKHs in the tardigrade Hysibius dujardini (pQLSFTGWGHamide), the rotifer Brachionus calycifloros (pQLTFSSDWSGamide), and the penis worm Priapulus caudatus (pQIFFSKGWRGamide). This is the first report, showing that AKH signaling is widespread in molluscs.

  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. 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 (cells, or > 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

  16. Toxicity of algal-derived aldehydes to two invertebrate species: do heavy metal pollutants have a synergistic effect?

    Science.gov (United States)

    Taylor, Rebecca L; Caldwell, Gary S; Bentley, Matthew G

    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 24h LD(50) values of 7 and 20 microM 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 microM of copper sulphate in solutions of decadienal resulted in the reduction of the 24h LD(50) of decadienal by approximately a third for both species. 1 microM of copper chloride in solutions of decadienal reduced the 24h LD(50) of decadienal to A. salina nauplii by approximately 11% and 1 microM zinc sulphate caused a reduction of only 3%. Pre-exposure of the organisms to 1 microM 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.

  17. 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

  18. 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.

  19. 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

  20. Early ontogenesis of the angelfish, Pterophyllum scalare Schultze, 1823 (Cichlidae

    Directory of Open Access Journals (Sweden)

    Agata Korzelecka-Orkisz

    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.

  1. Warming accelerates termination of a phytoplankton spring bloom by fungal parasites.

    Science.gov (United States)

    Frenken, Thijs; Velthuis, Mandy; de Senerpont Domis, Lisette N; Stephan, Susanne; Aben, Ralf; Kosten, Sarian; van Donk, Ellen; Van de Waal, Dedmer B

    2016-01-01

    Climate change is expected to favour infectious diseases across ecosystems worldwide. In freshwater and marine environments, parasites play a crucial role in controlling plankton population dynamics. Infection of phytoplankton populations will cause a transfer of carbon and nutrients into parasites, which may change the type of food available for higher trophic levels. Some phytoplankton species are inedible to zooplankton, and the termination of their population by parasites may liberate otherwise unavailable carbon and nutrients. Phytoplankton spring blooms often consist of large diatoms inedible for zooplankton, but the zoospores of their fungal parasites may serve as a food source for this higher trophic level. Here, we investigated the impact of warming on the fungal infection of a natural phytoplankton spring bloom and followed the response of a zooplankton community. Experiments were performed in ca. 1000 L indoor mesocosms exposed to a controlled seasonal temperature cycle and a warm (+4 °C) treatment in the period from March to June 2014. The spring bloom was dominated by the diatom Synedra. At the peak of infection over 40% of the Synedra population was infected by a fungal parasite (i.e. a chytrid) in both treatments. Warming did not affect the onset of the Synedra bloom, but accelerated its termination. Peak population density of Synedra tended to be lower in the warm treatments. Furthermore, Synedra carbon: phosphorus stoichiometry increased during the bloom, particularly in the control treatments. This indicates enhanced phosphorus limitation in the control treatments, which may have constrained chytrid development. Timing of the rotifer Keratella advanced in the warm treatments and closely followed chytrid infections. The chytrids' zoospores may thus have served as an alternative food source to Keratella. Our study thus emphasizes the importance of incorporating not only nutrient limitation and grazing, but also parasitism in understanding the

  2. Effects of repeated exposure to 4-nonylphenol on the zooplankton community in littoral enclosures

    Energy Technology Data Exchange (ETDEWEB)

    O`Halloran, S.L.; Liber, K.; Gangl, J.A. [Univ. of Wisconsin, Superior, WI (United States). Lake Superior Research Inst.; Knuth, M.L. [Environmental Protection Agency, Duluth, MN (United States). Mid-Continent Ecology Div.

    1999-03-01

    The effects of 4-nonylphenol (NP) on freshwater zooplankton were evaluated in 18 littoral enclosure mesocosms in northeastern Minnesota. The 18 enclosures were allocated to three blocks of six units with each block including two untreated control enclosures and one enclosure for each of four NP treatments. Treated enclosures received 11 applications of NP over a 20-d period between July 8 and 28, 1993. Maximum NP concentrations measured in the water column 2 h after each application averaged ({+-} SD) 5 {+-} 4, 23 {+-} 11, 76 {+-} 21, and 243 {+-} 41 {micro}g/L over the 11 applications. Nonylphenol dissipated rapidly from the water column but was more persistent in sediments and in/on macrophytes. All cladoceran and copepod taxa were significantly reduced in abundance at 243 {+-} 41 {micro}g/L; some sensitive taxa were also affected by 76 {+-} 21 and 23 {+-} 11 {micro}g/L. While many rotifer taxa were unaffected at any of the test concentrations, several were affected at {ge} 76 {+-} 21 {micro}g/L. Ostracods were only affected at 2,243 {+-} 41 {micro}g/L. No zooplankton taxon was affected at 5 {+-} 4 {micro}g/L. The period of maximum impact usually occurred within 1 to 7 d of the last NP application, and recovery to control abundance levels generally occurred within 7 to 28 d of the last NP application. Two sensitive taxa, Acroperus and Calanoida, did not recover at {ge} 76 {+-} 21 {micro}g/L by the end of the study. The maximum acceptable toxicant concentration for protection of all zooplankton taxa was estimated at {approximately} 10 {micro}g/L, although overall community diversity was unaffected at 23 {+-} 11. The water was the most probable route of NP exposure, but the greater persistence of NP residues in/on macrophytes may have contributed to the lack of recovery of some macrophyte-associated taxa.

  3. [Kinetics of zooplankton in an aquatic continuum: from the Marne River and reservoir to the Seine estuary].

    Science.gov (United States)

    Akopian, Maïa; Garnier, Josette; Pourriot, Roger

    2002-07-01

    A study was carried out within a 700-km river sector, including three types of ecosystems (a reservoir, a river and its estuary) to characterise the major features of zooplankton communities in the Seine Basin. In rivers, zooplankton biomass becomes significant only when the growth rate of the organisms is higher than the dilution rate (4-5th orders rivers, according to River Continuum Concept). Upstream, short residence times favour the development of small species (Rotifers) with low individual body weight and biomass. Conversely, larger species (microcrustaceans) develop more downstream, where increased residence time leads to autochthonous production (Riverine Productivity Model). Such a pattern is greatly modified by human impact. Zooplankton input from the Marne reservoir represents one type of disruption in the general upstream-downstream trend (according to the Serial Discontinuity Concept). This reservoir is a source of microcrustaceans; they rapidly disappear mainly through fish predation, and therefore have little impact on the river phytoplankton. Discontinuities, such as confluences, have a relatively small effect on the stock of zooplankton with regard to the water release from the reservoir, but they persist more downstream, because they have the same lotic origin. A few microhabitats with macrophytes play a small role for this canalised river, but they can modify locally the plankton community structure and composition. As a whole, the flux of zooplankton rises exponentially, whereas discharge increases linearly from upstream (4th order) to downstream (8th order). In the canalised sectors, Dreissena larvae build up an important biomass, adding to that of the zooplankton sensu stricto. Especially abundant in the downstream sector of the Marne and Seine Rivers, the larvae show a widespread colonisation of the benthic substrates by the adult Dreissena. One of the largest mussel colonies in the middle estuary can contribute to a rapid decrease of

  4. Plancto e hidrobiologia sanitária de tanques tropicais com dáfnias e rotíferos

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    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

  5. Ecotoxicological properties of wastewater treated using tertiary methods.

    Science.gov (United States)

    Petala, M; Samaras, P; Zouboulis, A; Kungolos, A; Sakellaropoulos, G

    2006-08-01

    The objective of this work was the examination of the efficiency of coagulation and ozonation processes for the production of reclaimed wastewater with low toxicity. Municipal secondary effluents were treated by FeCl3, Al2(SO4)3 (alum), and a commercial substance at metal ion concentrations of 0.5 and 1 mmol/L. Alternatively, the effluents were treated by ozonation in a semibatch ozone reactor. The feed gas was introduced at a flowrate of 3 L/min containing ozone at various concentrations, ranging between 2.5 and 8 mg/L; ozone residence times were 2, 5, 15, and 30 min. The toxic effects of the advanced treated effluents were examined by a battery of tests using the marine bacteria Vibrio fischeri, the freshwater crustaceans Daphnia magna, Daphnia pulex, and Thamnocephalus platyurus, and the rotifers Brachionus calyciflorus. The addition of alum decreased the toxic effect of reclaimed wastewater on immobilization of D. pulex, from 90 to 60%. Ozonation was also effective for toxicity removal, which decreased to 25% effect on D. pulex after treatment by 2.5 mg O3/L for 2 min. However, acute toxic effects after ozonation, were observed on V. fischeri and were related to ozone gas concentration and contact time. At the highest ozone dosage, the toxicity reached almost 100% inhibition of bioluminescence after 15 min. The toxicity of the ozonated effluents to bacteria decreased with sample storage time and was almost negligible after 48 h, indicating that the potential adverse effect of reclaimed wastewaters on receiving waters might be reduced by storage for a certain time.

  6. Short-term Effects of Abamectin on Water Quality and Community Structure of Plankton in Freshwater Aquaculture Ponds%阿维菌素对池塘水质和浮游生物群落结构的短期影响

    Institute of Scientific and Technical Information of China (English)

    董加沙; 何绪刚; 邓闵; 游鑫; 刘全圣; 覃雅; 陈荣

    2015-01-01

    T he short‐term effects of abamectin (0 .0375 mL/m3 ) on plankton community structure and water quality parameters were evaluated in three ponds with grass carp (Ctenopharyngodon idellus) as dominant species in Chonghu Lake (Gong’an ,Hubei) .The nitrate level was decreased significantly , whereas nitrate nitrogen ,ammonium nitrogen and total nitrogen were increased significantly .There were no significant differences in levels of phosphorus ,and soluble phosphate and in pH value .The microscopic examination showed 6 phyla with 80 species of phytoplankton ,32 genera with 41 species of zooplankton before abamectin administration ,and 7 phyla with 94 species of phytoplankton ,38 genera with 48 species of zooplankton after abamectin administration .Among them ,10 species of protozoa ,5 species rotifers ,9 species Chlorophyta ,1 species Bacillariophyta and 2 species Euglenophyta were only found before the application of abamectin;9 species protozoa ,10 species rotifers ,3 species adult copepods ,10 species Chlorophyta ,8 species Bacillariophyta , 7 species Euglenophyta , 1 species Pyrrophyta and 1 kind of Chrysophyte were only found after the application of abamectin .The dominant species of phytoplankton and zooplankton were changed significantly , and miniaturization species increased after the abamectin administration .The density and biomass of protozoa and cladocera were decreased significantly , the number of copepods increased significantly ,whereas the density and biomass of rotifers did not change much .Abamectin might result in drastic fluctuations in the density and biomass of phytoplankton such as Euglenophyta ,Cyanobacteria and Pyrrophyta .The application of abamectin in pond might easily lead to euglena blooms .The findings suggested that abamectin should be used with caution .%在湖北省公安县崇湖渔场3口面积均为0.268 hm2的主养草鱼池塘中,施用剂量0.0375 mL/m3的阿维菌素后,于第2、3、4、5、6 d采样,测定

  7. 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

  8. 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.

  9. 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

  10. The mate recognition protein gene mediates reproductive isolation and speciation in the Brachionus plicatilis cryptic species complex

    Directory of Open Access Journals (Sweden)

    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

  11. Plankton and Macrobiota Composition and Diversity of Three Tropical Freshwaters Rivers in Ogun and Ondo States, Southwest Nigeria

    Directory of Open Access Journals (Sweden)

    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

  12. 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.

  13. 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).

  14. 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.

  15. The pilot test on the treatment of refined cotton wastewater by A/O2 + adification-catalytic oxidation process%A/O2+酸析-催化氧化工艺处理精制棉废水的中试研究

    Institute of Scientific and Technical Information of China (English)

    同帜; 邹坦胜; 陈超产

    2011-01-01

    精制棉废水属于难处理的工业废水之一,本文采用A/O2+酸析-催化氧化工艺对其进行处理,并取得了良好的中试效果.生化部分的COD去除率达82%以上,色度去除率高于50%.实验结果表明,酸析过程中调节pH约为2 5,催化氧化过程中H2O2及FeSO4的投药量分别为0.8mg·L-1与160mg·L-1时,后处理的主要出水控制指标COD降至135mg · L-1以下,色度降至150倍以下.此外,通过观察发现脱氢酶活性较高,生物相中能反应水质良好的固着性纤毛虫和钟虫占优势.%A/O2 + adification-catalytic oxidation process is adopted to deal with the refined cotton wastewater which is one of the most intractable industrial wastewater, and there is a good result in the pilot test. In biological part, the removal rate of COD and color is respectively over 82% and 50%. When the pH in edification is about 2. 5, and the reagent dose of H2O2 and FeSO4 is respectively 0.8 mg/L and 160 mg/L, the main index COD of water after treatment drops below 135mg/L, and the color degree is less than 150 times. In addition, according to the observation, the dehydroenase's activity is higher, and the rotifer and vorticella are the dominant microbes in biological phase.

  16. SBR法后续处理垃圾渗滤液的影响因素%The Impact Factors of Subsequent Treatment on Landfill Leachate by SBR Process

    Institute of Scientific and Technical Information of China (English)

    王杰; 马溪平; 郑旭; 陈忠林; 庞香蕊

    2011-01-01

    为提高垃圾渗滤液处理效果,采用序批式活性污泥法(SBR)对垃圾渗滤液进行后续处理,考察了曝气时间、污泥浓度、沉降时间和pH对SBR工艺的影响.结果表明:经过30 d污泥培养驯化,测得SVIvi=80~100,SV30<0.3,MLSS=2.8~3.0/L,镜检可见大量钟虫、轮虫和原生动物等;在曝气时间8h,污泥浓度3.5g/L,沉降时间2.5h,pH=7的条件下使垃圾渗滤液中COD由1600 g/L下降到 352mg/L,NH3-N由485mg/L下降到86.8mg/L,SS由260mg/L下降到52 mg/L,去除率分别达到78%,82.1%和80%.%In order to improve the effects of treatment on landfill leachate, a sequencing batch reactor (SBR) processs was used to dispose the leachate which had been pre-treated by catalytic oxidation assisted with microwave.The results show that the sludge is mature after thirty days' s cultivation and domestication, and SVI is 80 ~ 100,SV30 < 0.3, MLSS is 2.8 ~ 3.0 g/L,a large number of vorticella,rotifer and protozoa are observed under microscope; when aeration time is 8 h,sludge concentration is 3.5 g/L,sedimentation time is 2.5 h, pH = 7, the COD is reduced from 1 600 mg/L to 352 mg/L,NH3-N is reduced from 485 mg/L to 86.8 mg/L, SS is reduced from 260 mg/L to 52 mg/L, the disposal rates attain 78% ,82.1% and 80% respectively.

  17. The applications of bio energizer and micatrol in paper-making wastewater treatment%生物促生剂、解毒剂在造纸废水处理中的应用

    Institute of Scientific and Technical Information of China (English)

    邹学圣; 肖鹏; 江淦福; 孙胤轶; 胡冲

    2014-01-01

    基于废水处理系统受到上游改变纸品生产工艺的影响,造成废水处理系统中活性污泥活性不强或死亡等问题,在造纸废水处理生化段使用生物促生剂Bio-energizer(BE)、解毒剂Micatrol(MT)。结果表明:受损的造纸废水处理系统在使用BE、MT 30d时间内,剂量仅为1mg/kg,能够使系统恢复。在不增加任何基建投入的情况下,使用BE/MT后,系统COD去除率能够达到89.3%,出水C O D能够稳定在100m g/l以下。使用BE/MT后,系统中微生物种类丰富,以钟虫等固着型纤毛虫类居多,出现了轮虫等后生动物,总体呈现多样化的趋势。%Because of the impact in wastewater treatment systems upstream due to the changes of process and the products, resulting in the activity of sludge not strong or death, Bio-energizer (BE) and Micatrol (MT) were used in wastewater biochemical treatment section. The results show that using BE and MT can enable the damaged papermaking wastewater treatment system to recover in 30 days, by measuring only 1 ppm. Without any additional investment in infrastructure, by using of BE and MT, the system COD removal rate can reach by 89.3%, COD in the eflfuent can be stabilized at 100mg/l or less. After the use of BE and MT, wide variety of microorganisms was found, most of them are Ciliates as Vorticella, Metazoanes as Rotifer, showing an overall trend of diversiifcation.

  18. Experimental study on the treatment of high Cl- high Ca2+and high COD wastewater by activated sludge process%活性污泥法处理高氯高钙高COD废水的实验研究

    Institute of Scientific and Technical Information of China (English)

    罗立; 孔秀琴

    2011-01-01

    研究了不同氯离子和钙离子浓度下活性污泥系统的沉降性能、COD去除率以及生物相变化规律.结果表明,对于COD为3 500 mg/L的废水,当Cl-<7 000 mg/L、Ca2+<3 940 mg/L时,COD去除率能达到90%以上,钟虫、轮虫等指示性微生物能在此浓度范围内生长、繁殖,污泥活性良好;当废水中Cl-和Ca2+质量浓度分别升至21 000、11 800 mg/L时,COD去除率下降至70.6%,此浓度范围内指示性微生物消失,嗜盐菌逐渐繁殖,活性污泥法仍具有明显的处理效果;继续升高废水中Cl-和Ca2+的浓度,COD去除率急剧下降,污泥解体,活性污泥系统趋于崩溃.%The settling property,variations of biofacies and COD removing rate of activated sludge systems with different Cl-and Ca2+ concentrations have been studied. The results show that when the COD is 3 500 mg/L,Cl- mass concentration less than 7 000 mg/L and Ca2+ mass concentration less than 3 940 mg/L,the COD removing rate reaches above 90%. In this concentration range, vorticella, rotifer and other indicative microbes are able to grow and reproduce, the sludge has high biological activity. When the mass concentrations of Cl-and Ca2+ increase to 21 000 mg/L and 11 800 mg/L,the COD removing rate decreases to 70.6%. In this concentration range,the indicative microbes disappear, and halophilic bacteria begin to reproduce, the sludge still has high activity. If the concentration of Cl- and Ca2+ continued to rise, the COD removing rate will fall sharply and activated sludge system will crumble.

  19. 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.

  20. Novas ocorrências de Lecane no plâncton de distintos ambientes da planície de inundação do alto rio Paraná (Brasil - DOI: 10.4025/actascibiolsci.v30i2.3636 New occurrences of Lecane in plankton in different environments of the upper Paraná river floodplain - DOI: 10.4025/actascibiolsci.v30i3.3636

    Directory of Open Access Journals (Sweden)

    Claudia Costa Bonecker

    2008-05-01

    Full Text Available planície de inundação do alto rio Paraná possui grande diversidade de rotíferos, com 288 táxons planctônicos registrados. Estudos realizados, nesse ecossistema, desde 1992, mostram que Lecanidae é a família mais especiosa, com 45 táxons registrados. Este trabalho teve como objetivo investigar a ocorrência dessa família em ambientes ainda não-estudados e consequentemente contribuir para a diversidade de rotíferos nessa planície de inundação. Foram registradas sete novas ocorrências de Lecane em amostras do plâncton: L. bifurca, L. rhytida, L. subtilis, L. crepida, L. bulla styrax, L. obtusa, e L. thienemanne. Embora os táxons descritos fossem encontrados no plâncton, essa família caracteriza-se por ser tipicamente não-planctônica. Dessa forma, visando ampliar o conhecimento sobre a diversidade dessa família na planície de inundação do alto rio Paraná, estudos exclusivamente taxonômicos devem explorar a grande heterogeneidade de hábitats presente nessa planície, como, por exemplo, a região marginal e as extensas áreas colonizadas por macrófitas aquáticas.The upper Paraná river floodplain possesses a great diversity of rotifers, with 288 planktonic taxa recorded. Surveys performed in this ecosystem since 1992 have shown that Lecanidae is the most abundant family, with 45 registered taxa. The main goal of the present study was to investigate the occurrence of this family in environments that have not yet been studied. Seven new occurrences of Lecane were recorded in plankton samples: L. bifurca, L. rhytida, L. subtilis, L. crepida, L. bulla styrax, L. obtusa, and L. thienemanne. Although the described taxa were found in plankton, this family is characterized by being typically non-planktonic. As such, exclusively taxonomic studies must explore the great habitat heterogeneity in this floodplain, e.g., the littoral region and the extensive areas colonized by aquatic macrophytes, aiming to expand knowledge on the

  1. Novas ocorrências de Lecane no plâncton de distintos ambientes da planície de inundação do alto rio Paraná = New occurrences of Lecane in plankton in different environments of the upper Paraná river floodplain

    Directory of Open Access Journals (Sweden)

    Ciro Yoshio Joko

    2008-04-01

    Full Text Available A planície de inundação do alto rio Paraná possui grande diversidade de rotíferos, com 288 táxons planctônicos registrados. Estudos realizados, nesse ecossistema, desde 1992, mostram que Lecanidae é a família mais especiosa, com 45 táxons registrados. Este trabalho teve como objetivo investigar a ocorrência dessa família em ambientes aindanão-estudados e consequentemente contribuir para a diversidade de rotíferos nessa planície de inundação. Foram registradas sete novas ocorrências de Lecane em amostras do plâncton: L. bifurca, L. rhytida, L. subtilis, L. crepida, L. bulla styrax, L. obtusa, e L.thienemanne. Embora os táxons descritos fossem encontrados no plâncton, essa família caracteriza-se por ser tipicamente não-planctônica. Dessa forma, visando ampliar o conhecimento sobre a diversidade dessa família na planície de inundação do alto rioParaná, estudos exclusivamente taxonômicos devem explorar a grande heterogeneidade de hábitats presente nessa planície, como, por exemplo, a região marginal e as extensas áreas colonizadas por macrófitas aquáticas.The upper Paraná river floodplain possesses a great diversity of rotifers, with 288 planktonic taxa recorded. Surveys performed in thisecosystem since 1992 have shown that Lecanidae is the most abundant family, with 45 registered taxa. The main goal of the present study was to investigate the occurrence of this family in environments that have not yet been studied. Seven new occurrences of Lecane were recorded in plankton samples: L. bifurca, L. rhytida, L. subtilis, L. crepida, L. bulla styrax, L. obtusa, and L. thienemanne. Although the described taxa were found in plankton, this family is characterized by being typically non-planktonic. As such, exclusively taxonomic studies must explore the great habitat heterogeneity in thisfloodplain, e.g., the littoral region and the extensive areas colonized by aquatic macrophytes, aiming to expand knowledge on the

  2. Preliminary studies on morphology and digestive tract development of tomato clownfish, Amphiprion frenatus under captive condition

    Directory of Open Access Journals (Sweden)

    Dedi F. Putra

    2012-03-01

    . Histology of digestive tract of A. frenatus larvae showed that the A. frenatus larvae have a straight tube closed at the mouth and histological differentiated along its length at newly hatching. It was found also several functional organs such as liver, midgut and stomach at 1 DAH. It was indicated with the appearance of developed and functional digestive tract at first day hatching larvae. Therefore, live foods such as rotifer are suitable to be fed at early larvae after hatching.

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

    Science.gov (United States)

    Schulz, Jan; Peck, Myron A.; Barz, Kristina; Schmidt, Jörn Oliver; Hansen, Frank C.; Peters, Janna; Renz, Jasmin; Dickmann, Miriam; Mohrholz, Volker; Dutz, Jörg; Hirche, Hans-Jürgen

    2012-12-01

    The deep basins in the Baltic Sea such as the Bornholm Basin (BB) are subject to seasonal changes in the strength of physico-chemical stratification. These depth-related changes in key abiotic factors are strong drivers of habitat partitioning by the autochthonous zooplankton community. Species-specific ecophysiological preferences often result in both seasonal and inter-annual changes in vertical abundance that, when combined with depth-specific water currents, also lead to horizontal differences in spatial distribution. The present study documented the seasonal and depth-specific changes in the abundance and species composition of zooplankton in the BB based upon broad-scale survey data: 832 vertically-resolved (10 m) multinet samples collected at nine stations between March 2002 and May 2003. Changes in the zooplankton community were significantly correlated with changes in ambient hydrography. Each of five 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 on a multivariate approach and the evaluation of vertical distribution patterns, five major habitat utilisation modes were identified that were based, to a large extent, on the dynamics of thermal and haline stratification of the Baltic Sea. Our statistical analysis of one of the most thorough datasets collected on Baltic zooplankton in recent decades reveals some of the factors that make this stratified system highly dynamic with respect to the spatial overlap between

  4. Ciliate community structure and interactions within the planktonic food web in two alpine lakes of contrasting transparency.

    Science.gov (United States)

    Kammerlander, Barbara; Koinig, Karin A; Rott, Eugen; Sommaruga, Ruben; Tartarotti, Barbara; Trattner, Florian; Sonntag, Bettina

    2016-11-01

    Climate warming is accelerating the retreat of glaciers and recently, many 'new' glacial turbid lakes have been created. In the course of time, the loss of the hydrological connectivity to a glacier causes, however, changes in their water turbidity and turns these ecosystems into clear ones.To understand potential differences in the food-web structure between glacier-fed turbid and clear alpine lakes, we sampled ciliates, phyto-, bacterio- and zooplankton in one clear and one glacial turbid alpine lake, and measured key physicochemical parameters. In particular, we focused on the ciliate community and the potential drivers for their abundance distribution.In both lakes, the zooplankton community was similar and dominated by the copepod Cyclops abyssorum tatricus and rotifers including Polyarthra dolichoptera, Keratella hiemalis, Keratella cochlearis and Notholca squamula. The phytoplankton community structure differed and it was dominated by the planktonic diatom Fragilaria tenera and the cryptophyte alga Plagioselmis nannoplanctica in the glacial turbid lake, while chrysophytes and dinoflagellates were predominant in the clear one.Ciliate abundance and richness were higher in the glacial turbid lake (∼4000-27 800 Ind L(-1), up to 29 species) than in the clear lake (∼570-7150 Ind L(-1), up to eight species). The dominant species were Balanion planctonicum, Askenasia cf. chlorelligera, Urotricha cf. furcata and Mesodinium cf. acarus. The same species dominated in both lakes, except for Mesodinium cf. acarus and some particle-associated ciliates, which occurred exclusively in the glacial turbid lake. The relative underwater solar irradiance (i.e. percentage of PAR and UVR at depth) significantly explained their abundance distribution pattern, especially in the clear water lake. In the glacial turbid lake, the abundance of the dominating ciliate taxa was mainly explained by the presence of predatory zooplankton.Our results revealed an unexpected high

  5. 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

  6. Study on Artificial Dom estication and Seed ling Cultivation of Hippocampus trimaculatus%三斑海马的驯化与苗种培育研究

    Institute of Scientific and Technical Information of China (English)

    骆大鹏; 刘庆明; 邱名毅; 赵志英; 周海珠

    2016-01-01

    [目的]通过对三斑海马的驯化与苗种培育试验,丰富三斑海马的生物学基础资料。[方法]从海南本地收集三斑海马亲本,开展人工驯化和苗种培育,并探索其繁殖生物学行为。[结果]亲鱼驯化成活率达到85%,获得三斑海马初孵幼苗2.9万尾,培育1月龄鱼苗1.1万尾,海马最适开口饵料为“小球藻+轮虫+桡足类幼体”。三斑海马亲鱼抱卵量和孵化量存在个体差异,亲鱼抱卵量最少350粒/尾,最多1020粒/尾,平均660粒/尾。亲鱼孵化量最少220尾,最多720尾,平均580尾。[结论]该研究结果可为海马的苗种繁育和人工养殖提供科学依据。%Abts ract [ Objective] To make the artificial domestication and seedling cultivation experiments of Hippocampus tir maculatus Leach and en-rich the biological basic data of H.trimac ulatu sLeach .[ Method] The parent fishes were collected from Hainan to make artificial domestica-tion and seedling cultivation experiments.And their reproductive biological behaviors were studied.[ Result] The survival rate of parent fish after artificial domestication reached 85%.29 thousand hatched fries of H.trimacula tus Leach were harvested, and 11 thousand one-month-old fish fries were cultivated.The optimum initial bait for H.trimaculatus Leach was “chlorella +rotifers +copepods larvae”.There were individual differences in the amount of egg load and the amount of hatched eggs in H.trimaculatus Leach.The minimum, maximum and aver-age values of egg load amount per parent fish were 350, 1 020 and 660 respectively.The minimum, maximum and average values of the amount of hatched eggs per parent fish were 220, 720 and 550 respectively.[ Conclusion] The results can provide scientific basis for the off-spring cultivation and artificial breeding of H.trimaculatus Leach.

  7. Tree species traits influence soil physical, chemical, and biological properties in high elevation forests.

    Directory of Open Access Journals (Sweden)

    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

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. Morphological development and growth pattern of Verasper variegatus,Temminck et Schlegel in early life stages%圆斑星鲽的早期生长发育特征

    Institute of Scientific and Technical Information of China (English)

    宁鑫; 柳学周; 孙中之; 徐永江; 王妍妍

    2011-01-01

    Morphological and quantitative characteristics of Verasper variegatus in early life stages including embryonic development, yolk sac larva, pre-flexion larva, post-flexion larva, and juveniles were recorded. The eggs are 1.75mm 0. 08mm in diameter, without oil globule and spherical in shape when they are suspended in sea water. There is negative a relationship between the temperature and the hatching time, and the calculated lower threshold temperature for hatching of embryos is 5.14 ℃. The larvae hatched out 159h post fertilization at temperatures of 11±0.5 C, salinity of 31-32, and DO≥Smg/L. The newly hatched larvae is transparent and 4.95±0. 15mm in total length. Larval development and growth completely depended on the energy from the yolk sac and oil globe till 7 DAH (days after hatching). Meantime, mouth and anus opened, larvae entered the mixed feeding stage. Larvae entered the complete exogenous feeding stage after the yolk was completely absorbed at 11DAH. The first feeding food was L type rotifers Brachionus plicatilis. Larvae began to feed rotifers at 7 DAH. At 11 DAH, larvae were fed nauplii of brine shrimp Artemia salina at densities of 0.5 1.5 ind./mi till 46 DAH. Weaning to commercial diet started at 31 DAH and larvae fed mainly commercial diet after 40 DAH. There is no swim bladder present all through the early life history. The flexion of notochord started at 17 DAH at a total length of 7.32 0.23 mm (n=30), and finished at 33DAH when the total length reached 11.2 0.33 mm (n=30). Meanwhile, metamorphosis began at 33 DAH and completed at 50 DAH with the left eye moved completely to the right side, and the juveniles entered the bottom life stage. At 70 DAH, lateral line formed and the juveniles entered the young stage with the total length up to 25.3 3.23 mm (n=30), with similar appearance as the adults. The dorsal fin, pectoral fin, pelvic fin, caudal fin, and anal fin reached their full numbers at 70DAH. There were 4-5 black spots on the dorsal

  13. 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

  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. 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.

  16. 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.

  17. 青海省黑河上游水生生物的调查研究%Investigation on aquatic organisms in the upper stream of Heihe River in Qinghai Province, China

    Institute of Scientific and Technical Information of China (English)

    唐文家; 赵霞; 张妹婷

    2012-01-01

    于2010年5月对青海省黑河上游水生生物进行了调查,共采集到浮游植物4门39种,其中硅藻门25种,占64.10%,绿藻门7种,占17.95%,蓝藻门6种,占15.39%,隐藻门1种,占2.56%;浮游植物数量为23.63 ~ 137.66万个/L,平均为91.30万个/L,生物量为0.1796~1.0841 mg/L,平均为0.7306mg/L.采集到浮游动物3类13种,其中原生动物5种,占38.46%,轮虫7种,占53.85%,桡足类1种,占7.69%;浮游动物数量为1.52~ 11.22个/L,平均为6.06个/L,生物量为0.0076~0.0957 mg/L,平均为0.0353 mg/L.采集到鱼类4种,黄河裸裂尻鱼Schizopygopsis pylzovi Kessler为新增补记录.物种丰富度指数(D)为0.5247,香农-纳威生物多样性指数(H)为0.7887,物种丰富度和生物多样性指数均偏低.%An investigation on aquatic organisms was conducted in the upper stream of Heihe River in Qinghai Province, China, in May 2010. There were 39 phytoplankton species belonging to Bacillariophyta, Chlorophyta, Cyanophyta and Cryptophyta, including 25 diatoms, accounting for 64. 10% of the total amount; 7 green algae, accounting for 17. 95% ; and 6 blue green algae, account for 15. 39%. The amount of the algae was varied from 236 300 ind./L to 1 376 600 ind./L with an average of 913 000 ind./L, while the biomass was arranged from 0. 1796 mg/L to 1.0841 mg/L with an average of 0.7306 mg/L. There were 13 species zooplankton, including 5 species protozoan accounting for 38. 64% , 7 species rotifers accounting for 53. 85% and 1 species copepod accounting for 7. 69 % . The amount of zooplankton was varied from 1.52 ind. /L to 11.22 ind. /L with an average of 6.06 ind. /L, while the biomass was ranged from 0.0076 mg/L to 0.0957 mg/L with an average of 0.0353 mg/L. Four species of fishes were found, among which Schizopygopsis pylzovi Kessler was the new recorded species in this region. The Richness index (D) was found to be 0.5247, Shannon-Wiener index (H) 0.7887, indicating that both the Richness index (D

  18. 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.

  19. 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

  20. 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

  1. Evaluation de l'effet de l'environnement et de l'alimentation sur l'apparition d'anomalies de développement chez l'alevin de bar (Dicentrarchus labrax

    Directory of Open Access Journals (Sweden)

    MENU B.

    1998-07-01

    Full Text Available Une ponte naturelle de bar, obtenue dans les installations expérimentales de Palavas, est mise en élevage dans ce même laboratoire et dans celui de Brest, après un transport fictif ou réel. Les protocoles spécifiques de chacun des deux laboratoires sont utilisés sans changer le contexte d'élevage particulier de chacun des deux sites : mise à jeun à l'obscurité jusqu'à 160 degrés jours et première alimentation sur Artemia à Palavas en bacs de 500 litres et, première alimentation à 75 degrés jours sur rotifères à Brest en bacs de 250 litres et de 35 litres. Dans les conditions d'environnement comparables (bacs de 250 litres à Brest une période de jeûne est également testée, de 75 à 160 degrés jours, soit en obscurité sans aération, soit sous éclairage continu avec aération. Les malformations des vertèbres, des maxillaires, des opercules (courts et soulevés, la non-inflation de la vessie natatoire et la présence de calculs urinaires sont relevées à 3 mois sur tous les lots. Plusieurs malformations apparaissent inféodées à un site ou un traitement particulier : cristaux urinaires à Palavas, vessies natatoires non fonctionnelles à Brest, maxillaires anormaux en bac de 35 litres. Les opercules soulevés sont observés dans deux installations utilisant des méthodologies différentes mais sont négligeables dans la ligne d'élevage où les tests méthodologiques ont été effectués. Les taux de survie sont significativement influencés par les traitements. La répartition des fréquences des lordoses entre les sites ou les différents traitements peut s'interpréter comme une conséquence de mortalités sélectives. L'association entre les lordoses et les vessies natatoires non fonctionnelles, déjà connue chez le bar, est observée. L'étude des fréquences croisées des malformations montre également que les opercules courts sont 10 fois plus fréquents chez les individus dont les vessies natatoires ne sont

  2. 凡纳滨对虾设施养殖池塘浮游生物群落结构及多样性研究%Community structure and biodiversity of plankton in Litopenaeus vannamei culture pond

    Institute of Scientific and Technical Information of China (English)

    何京; 陈晨; 王一农; 钟硕楠; 刘静; 林志华

    2015-01-01

    The species, quantity changes and biodiversity on the culture pond of Litopenaeus vannamei were studied . The results showed that the total number of species of phytoplankton were 40, out of which the Bacillariophyta takes up 27 species;the Chlo-rophyta had 7 species;and the Cyanophyta had 4 species;the Xanthophyta had one specie and Pyrrophyta had one specie. The total number of species of zooplankton were 17, out of which the Protozoa had 8 species;the Rotifers had 6 species;the Cladocerans had 3 species. The population density of phytoplankton was 4.4×104-6.3×102 mg/mL, the biomass was 12.6-882.0 mg/L, the Shannon-Wie-ner index was 0-3.17, the Margalef richness index was 0.56-0.95, the Pielou evenness index was 0.19-0.90. The population density of zooplankton was 12.6mg/L-1~882.0 mg/mL, method the biomass was 1.2×102-2.7×102 mg/L.The species number and the density were little than those in the sea. In the same cultivation, there are big different in the species and density of plankton.%研究了后期凡纳滨对虾设施养殖29个池塘中浮游生物的种类组成、数量差异及种类多样性。结果表明:共鉴定出浮游植物5门25属40种,浮游动物3门14属17种,未鉴定种类8种。其中硅藻门27种,绿藻门7种,蓝藻门4种,黄藻门1种,甲藻门1种;原生动物门8种,轮虫类6种,枝角类3种。29个池塘浮游植物丰度6.3×102~4.4×104 cell/mL,生物量12.6~882.0 mg/L,Shannon-Wiener多样性指数0~3.17,Margalef丰富度指数范围0.56~0.95,Pielou均匀度0.19~0.90;浮游动物丰度12.6 mg/L~882.0 mg/mL,生物量1.2×102~2.7×102 mg/L。凡纳滨对虾养殖池塘中,浮游生物种类相对自然海区少、密度大。在相同管理模式下,池塘中浮游生物种类和数量有较大差异,多样性指数也有较大差异。

  3. 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

  4. 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.

  5. 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.

  6. 东江干流浮游动物群落结构特征及与水质的关系%COMMUNITY STRUCTURE OF ZOOPLANKTON AND ITS RELATION WITH WATER QUALITY IN DONGJIANG RIVER

    Institute of Scientific and Technical Information of China (English)

    王博; 廖剑宇; 刘全儒; 江源

    2013-01-01

    对东江干流浮游动物进行调查,并分析了其群落结构、生物量和丰度的空间分布特征及与主要环境因子的关系.46个采样点中共发现52种浮游动物,浮游动物的密度范围在1~3640 L-1之间,其中原生动物与轮虫类占总浮游动物密度的77%.优势种属为钟虫(Vorticella)、侠盗虫(Strobilidium)、团睥睨虫(Askenasiavolvox)、砂壳虫(Difflugia)、针簇多肢轮虫(Polyarthra trigla )、颈沟基合溞(Bosminopsis deiteris )、广布中剑水蚤(Mesocyclops leuckarti ).根据浮游动物各项指标值显示,东江干流水质良好.相关分析结果表明:浮游动物密度以及属类数均与叶绿素 a、CODMn、DO、电导率呈极显著的正相关关系(P<0.01);不同类浮游动物与水质因子相关性程度不同,原生动物与电导率呈极显著正相关,轮虫与CODMn及温度呈极显著正相关,枝角类和桡足类均与 DO 呈极显著正相关.浮游动物的空间分布与水体水质因子关系密切.%Community structure of zooplankton in Dongj iang river such as genus richness,density and biodiversities was investigated, regression analysis between community index of phytoplankon and water quality parameters were performed.Fifty two genus of zooplankton were identified.Density of phytoplankton was found to be from 1~3 640 L-1 ,with 77% protozoa and rotifera.Vorticella sp.,Strobilidium sp., Askenasia volvox,Difflugia sp.and Polyarthra trigla were found to be dominant in algae community. Judging from values of zooplankton comprehensive index,Dongjiang river was not seriously polluted.Density of zooplankton was found to be positively correlated with CODMn,conductivity value,DO and Chla (P<0.01). Water quality factor correlation degree was different with different zooplankton.Protozoa was positively correlated with conductivity,rotifer was positively correlated with CODMn and temperature,cladocera and copepoda was positively correlated with DO. Zooplankton was

  7. Microfauna communities and their relationship with the performance of an activated sludge system for coking wastewater treatment%焦化废水活性污泥法处理中微型动物群落及其与处理性能之间的关系

    Institute of Scientific and Technical Information of China (English)

    胡小兵; 饶强; 叶星; 周东宝; 完颜健飞

    2015-01-01

    为了分析难降解焦化废水活性污泥法处理中的微型动物群落特征,本研究考察了活性污泥法焦化废水处理厂中的微型动物群落,分析了其与处理性能之间的相互关系.结果发现,本研究共采集的64个水样中,鉴别出28个种属微型动物,其中,原生动物27种(22种纤毛虫、4种鞭毛虫、1种有壳变形虫),1个类群微型后生动物.固着型和匍匐型纤毛虫为共优势群,固着型小口钟虫(Vorticella microstoma)为绝对优势种.除小口钟虫(V.microstoma)(出现频率100%)外,出现频率较高的种类还有轮虫(rotifers)(97%)、沟钟虫(Vorticella convallaria)(69%)等.与常规废水活性污泥法处理系统相比,焦化废水处理系统中的微型动物种类和数量相对偏低.相关性分析结果表明,生物学参数与出水水质、运行参数间存在着不同的相关性.其中,累枝虫属(Epatyla spp.)与出水氨氮(r=-0.740,p<0.01)、氰化物(r=0.509,p<0.05)和DO(r=0.514,p<0.05)存在着显著的相关性;吸管虫属(Podophrya spp.)与硝化效率呈显著负相关(p<0.05),它们可作为系统处理性能参数的指示微生物;其他种属与出水水质和运行参数间的相关性不显著(p>0.05).因子分析揭示了与系统相关联的潜在的重要影响因素,以及某些微型动物种属间存在的相互关系.

  8. 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.

  9. 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

  10. 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

  11. 大黄鱼(♀)与黄姑鱼(♂)人工杂交子代的胚胎发育%Embryonic Development of Hybrids of Large Yellow Croaker(Pseudosciaena crocea,♀)×Spotted Maigre(Nibea albiflora,♂)

    Institute of Scientific and Technical Information of China (English)

    史会来; 王奋芬; 楼宝; 辛俭; 毛国民; 徐冬冬; 詹炜

    2011-01-01

    Hybridization of large yellow croaker(Pseudosciaena crocea,♀) with mean body weight of 405 g,and mean body length of 27.9 cm.× spotted maigre(Nibea albiflora,♂)with with mean body weight of 390 g,and mean body length of 24.8 cm was artificially performed by dry fertilization and the embryonic development was observed in October of 2008.The pelagic fertilized eggs were 1.18mm in diameter,and had one oil globule with 379.8μm diameter in average.The fertilized eggs were incubated in sea water at a water temperature of 25.8 ~ 26.2℃ and a salinity of 26 and hatched by 18 h 55 min.The embryonic development of the hybrids was divided into egg cleavage stage,blastula stage,gastrula stage,heart beating stage,muscular contraction stage and hatching stage.The newly hatched larvae had total body length of 2.75 ~ 2.98 mm,with deformity of about 30%,fertilization success of 14.4%,and hatching rate of 31.9%.About 50000 larvae were obtained,beginning to feed rotifer as natural food three days after hatching,and ingesting copepods as food seven days after hatching.%2008年10月,在福建宁德水产技术推广站进行了大黄鱼(Pseudosciaena crocea,♀)×黄姑鱼(Nibea alb-iflora,♂)杂交,观察了杂交子代胚胎发育。大黄鱼和黄姑鱼亲鱼平均体质量和体长分别为405 g、27.9 cm和390g、24.8cm,采用干法人工授精。受精卵浮性,为单油球端黄卵,卵径1060~1500μm,油球379.8μm左右。在水温25.8~26.2℃,盐度26的条件下,经18h55min半数受精卵破膜,胚胎发育分为卵裂期、囊胚期、原肠期、肌节出现期、心跳期、肌肉效应期、出膜前期和出膜期,初孵仔鱼全长2.75~2.98mm,受精率约为14.4%,孵化率约为31.9%,畸形率约为30%。共培育杂交初孵仔鱼5万尾。3日龄仔鱼开口摄食轮虫,7日龄开始摄食小型挠足类。

  12. Plankton communities and summertime declines in algal abundance associated with low dissolved oxygen in the Tualatin River, Oregon

    Science.gov (United States)

    Carpenter, Kurt D.; Rounds, Stewart A.

    2013-01-01

    during much of the growing season. A general seasonal trend in the phytoplankton assemblages was observed, with dominance by filamentous centric diatoms Stephanodiscus and Melosira in spring and early summer, and flagellated cryptophytes and green algae, particularly Chlamydomonas sp., in late-summer; or, in 2008, dominance by blue-green algae Anabaena flos-aquae and Aphanizomenon flos-aquae during the Wapato Lake bloom event. There were 99 zooplankton taxa identified from the Tualatin River in 2006–08, composed primarily of cladocerans, copepods, and rotifers. A seasonal increase in zooplankton abundance was observed in early summer just as or shortly after the phytoplankton population began to increase, with populations growing to 15,000−120,000 organisms per cubic meter in the lower river. Zooplankton abundance showed a predictable and distinct longitudinal downstream increase, particularly downstream of Highway 99W (RM 11.6). Although grazing rates were not measured, the data suggest that, at times, zooplankton grazing may affect algal abundance and species composition in the Tualatin River, with diatoms becoming relatively less abundant and flagellated cryptophytes and green algae relatively more abundant during periods when zooplankton densities were highest. Multivariate statistical analyses identified soluble reactive phosphorus (SRP), natural flow, flow augmentation, and WWTF effluent as important factors influencing Tualatin River phytoplankton populations, with zooplankton density (particularly rotifers and copepods), specific conductance, chloride, and water temperature also having an important influence. Although SRP was highly correlated with the plankton communities, that correlation was likely the result of high or low algal activity (uptake) as SRP concentrations were often reduced to low levels during blooms. While previous studies have already established that phosphorus, among other factors such as flow, places a theoretical cap on the size of the

  13. 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.

  14. 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

  15. Patógenos que afectan el cultivo de Litopenaeus vannamei en ambiente marino y dulceacuícola en el estado de Baja California, México - Pathogens that affect crop Litopenaeus vannamei in marine environment and freshwater in the state of Baja California, México

    Directory of Open Access Journals (Sweden)

    Jorge Cáceres Martínez

    2010-03-01

    discuten los resultados en sobrevivencia con la presencia de patógenos y epibiontes presentes. En general, se observó un patrón de incremento de epibiontes hacia el final del período de cultivo y una disminución en la concentración de oxígeno en el estanque, haciendo evidente el punto crítico al que se expone la producción, cuando se combinan epibiontes y condiciones ambientales. SummaryBetween April 2003 and September 2006 a study was carried out todetermine symbionts and pathogens in white shrimp, Litopenaeusvannamei, cultivated in seven different farms in the state of Baja California, Mexico; these farms used three different saline environments. The study included fresh tissue samples, histopathologic testing, and specific molecular tests for White Spot Syndrome Virus (WSSV. Colonies of the peritrichous protozoan Zoothamnium sp. were found attached to gills in shrimp grown in marine environments (with salinity of 35.9 ups with prevalence ranging from 0 to 80% and a severity range of 1to 2 (P=0-80%, GS=1-2, where the filamentous bacteria Leucothrix sp.(P=0-50%, GS=1-3 was also found. In cultured shrimps with groundwater (salinity of 1.6 ups, the epibionts associated to the gills were diatoms (P=0-20%, GS=1-2 and rotifers (P=0-40%, GS=1-2. And shrimps, whereriver-derived water was used (salinity ranging from 0.8 to 5.3 ups,colonial euglenoid algae (P=0-100% GS=1-2, peritrichous protozoaEpistylis sp. (P=0-100%, GS= 1-3 and filamentous bacteria Leucothrix sp. (P= 0-100, GS=1-3 were found, with branchials epibions. Histopathologic tests revealed melanosis, necrosis and hemocytic infiltration in gills, associated to epibionts and environmental conditions. Futhermore Cowdry type “A” inclusion bodies related to Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV, were also observed in shrimp of all of the farms studied (P= 2-36 % y GS=1-2. The histopathologic test performed on the shrimp hepatopancreas revealed the presence of bacterial infections (P=15

  16. 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

  17. 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.

  18. 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

  19. Community structure and its relationship with environmental factors in zooplankton in Jinghe River system in Northwest China%泾河水系浮游动物群落结构及其与环境因子的关系

    Institute of Scientific and Technical Information of China (English)

    白海锋; 李丽娟; 项珍龙; 王博涵; 殷旭旺; 徐宗学; 沈红保; 问思恩

    2015-01-01

    为了解渭河流域最大支流———泾河水系的浮游动物群落结构特征及水质状况,于2012年10月对该水系15个采样断面的浮游动物群落和水环境理化特征进行了调查,并运用Canoco 4.5软件对浮游动物群落与环境因子进行典范对应分析。结果表明:泾河水系浮游动物种类共有28属42种,其中轮虫占主导,原生动物和桡足类次之,分别占种类总数的85.72%、7.14%和7.14%;游动物密度为0.9~36.0 ind./L,平均值为8.5 ind./L,生物量为0.0011~0.0425 mg/L,平均值为0.0097 mg/L;浮游动物优势种有8种;Shannon-Weiner多样性指数(H)平均值为2.38, Pielou均匀度指数(J)平均值为0.75;浮游动物密度聚类分析结果显示,泾河水系各断面浮游动物可分为4大类群;典范对应分析( CCA)结果显示,驱动泾河水系浮游动物群落结构形成的水环境因子为水温、海拔和河宽。基于浮游动物群落结构特征,根据物种多样性指数对泾河水系水质状况进行评价,结果显示,泾河水系水质属于β-中污染,浮游动物群落结构趋于简单化,需要加强流域生态建设及污染治理。%The community structure of zooplankton and characteristics of environment were investigated in 15 sam-pling sites in the Jinghe River system, as the largest tributary of the Weihe River basin, Northwest China, in au-tumn of 2012, and analyzed by canonical correspondence analysis using Canoco 4. 5 software. It was found that there were 42 zooplankton species belonging to 28 genera, with dominant rotifers accounting for 85. 72% in the spe-cies composition, followed by protozoa (7. 14%) and copepod (7. 14%). The zooplankton had a density of 0. 9-36. 0 ind. /L, with an average of 8. 5 ind. /L, and biomass of 0. 001 1-0. 042 5 mg/L, with an average biomass of 0. 009 7 mg/L. There were eight dominant species of zooplankton in Jinghe River system, with average Shannon-Weiner species diversity index( H) of 2. 38 and