WorldWideScience

Sample records for bdelloidea rotifera syndermata

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

    Directory of Open Access Journals (Sweden)

    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.

  2. Otostephanos (Rotifera, Bdelloidea, Habrotrochidae) with the description of two new species

    Czech Academy of Sciences Publication Activity Database

    Iakovenko, N.; Kašparová, Eva; Plewka, M.; Janko, Karel

    2013-01-01

    Roč. 11, č. 4 (2013), s. 477-494 ISSN 1477-2000 R&D Projects: GA AV ČR KJB600450903 Institutional support: RVO:67985904 Keywords : macrotrachela Quadricornifera rotifera * Bdelloid taxonomy * biodiversity Subject RIV: EG - Zoology Impact factor: 2.153, year: 2013

  3. Rates of Filtration and Ingestion of a Microalga by Philodina roseola (Rotifera: Bdelloidea

    Directory of Open Access Journals (Sweden)

    Raquel Aparecida Moreira

    2016-05-01

    Full Text Available Rotifers play an important role in biogeochemical cycles 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.

  4. Biodiversity and spatial distribution of Rotifera in a shallow ...

    African Journals Online (AJOL)

    Biodiversity and spatial distribution of Rotifera in a shallow hyperuetrophic tropical Lake (Cameroon). TSH Zebaze, T Njine, N Kemka, D Niyitegeka, M Nola, MS Foto, E Djiukom, G Ajeagah, HJ Dumont ...

  5. A Taxonomical Study on the Rotifera Fauna in Pertek Region of Keban Dam Lake.

    Directory of Open Access Journals (Sweden)

    Ayda Tellioğlu

    2015-12-01

    Full Text Available Keban Baraj Gölü Pertek Bölgesi’nin rotifer faunası üzerine taksonomik bir çalışma. Bu çalışmada, Keban Baraj Gölü Pertek Bölgesi’nin Rotifera faunası Ağustos 2002- Temmuz 2003 tarihleri arasında taksonomik açıdan incelenmiştir. Gölde, Rotifera filumuna ait 20 tür tespit edilmiştir, bu türlerden 6’sı (Polyarthra remata, Asplanchna sieboldi, Hexarthra mira, Hexarthra fennica, Testudinella patina ve Trichocerca cylindrica bu göl için yeni kayıttır

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

    Directory of Open Access Journals (Sweden)

    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.

  7. Spermatozoon of the freshwater rotifer Brachionus calyciflorus (Rotifera, Monogononta): Advances in morphological and ultrastructural studies.

    Science.gov (United States)

    Gu, Shuyu; Li, Lian; Liang, Luxiaoxue; Liu, Xuezhou; Ouyang, Kai; Li, Jing; Yang, Jiaxin

    2015-09-01

    The morphological and ultrastructural features of the spermatozoon in Brachionus calyciflorus are described using light, fluorescence and transmission electron microscopy (TEM). The mature spermatozoon, which appears to be thread-like, is composed of a slightly expanded anterior of cell body region and a flagellum region without acrosome. The cell body region and flagellum region are respectively 16-27μm and 20-33μm in length (n=60). The spermatozoon is characterized by a mass of dense tubular materials, which occupy most of the cell. Some mitochondria are distributed around the nuclear region in the anterior of the cell body region, while in the posterior portion of cell body, the chromatin often contains a single lobated nucleus arranged at the center of cell. The flagellum contains the classic axoneme (9×2+2) and possesses lateral undulating membrane. Mature B. calyciflorus males have no germ cell stages earlier than the spermatids in the testis. TEM examination reveals rigid rods as well as predominant typical spermatozoon in the testis. Observations, based on successive photographs and videos, enabled a first-time recording of the unique inverted movement of the spermatozoon, which indicated that the movement of the spermatozoon is driven by the flagellum. Our study also provides further supplementary insights into the phylogenetic systematics of the Rotifera. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Antioxidants can extend lifespan of Brachionus manjavacas (Rotifera), but only in a few combinations

    Science.gov (United States)

    Fields, Allison M.; Johnston, Rachel K.

    2013-01-01

    Animal cells are protected from oxidative damage by an antioxidant network operating as a coordinated system, with strong synergistic interactions. Lifespan studies with whole animals are expensive and laborious, so there has been little investigation of which antioxidant interactions might be useful for life extension. Animals in the phylum Rotifera are particularly promising models for aging studies because they are small (0.1–1 mm), have short, two-week lifespan, display typical patterns of animal aging, and have well characterized, easy to measure phenotypes of aging and senescence. One class of interventions that has consistently produced significant rotifer life extension is antioxidants. Although the mechanism of antioxidant effects on animal aging remains controversial, the ability of some antioxidant supplements to extend rotifer lifespan was unequivocal. We found that exposing rotifers to certain combinations of antioxidant supplements can produce up to about 20% longer lifespan, but that most antioxidants have no effect. We performed life table tests with 20 single antioxidants and none yielded significant rotifer life extension. We tested 60 two-way combinations of selected antioxidants and only seven (12%) produced significant rotifer life extension. None of the 20 three- and four-way antioxidant combinations tested yielded significant rotifer life extension. These observations suggest that dietary exposure of antioxidants can extend rotifer lifespan, but most antioxidants do not. We observed significant rotifer life extension only when antioxidants were paired with trolox, N-acetyl cysteine, l-carnosine, or EUK-8. This illustrates that antioxidant treatments capable of rotifer life extension are patchily distributed in the parameter space, so large regions must be searched to find them. It furthermore underscores the value of the rotifer model to conduct rapid, facile life table experiments with many treatments, which makes such a search feasible

  9. 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. 

  10. Pastas de Rhodomonas salina (Cryptophyta como alimento para Brachionus plicatilis (Rotifera

    Directory of Open Access Journals (Sweden)

    Miguel Guevara

    2011-12-01

    Full Text Available Pastas de Rhodomonas salina, obtenidas mediante centrifugación y floculación con quitosano y preservadas con o sin vitamina C, a -20°C fueron evaluadas bioquímicamente y proporcionadas como alimento al rotífero Brachionus plicatilis. Las pastas microalgales: (1 centrifugada y con vitamina C (CV, (2 centrifugada y sin vitamina C (C, (3 floculada y con vitamina C (FV y (4 floculada y sin adición de vitamina C (F; mantuvieron sus contenidos de proteínas y lípidos totales similares al cultivo control, con valores de 40.0±2.32% y 12.0±1.45%, respectivamente. La relación feofitina a/clorofila a fue similar (0.09-0.11 entre las pastas centrifugadas y el cultivo control, pero mayor en las pastas floculadas (1.28-1.48. Las pastas centrifugadas presentaron porcentajes de PUFAs totales, EPA y DHA similares al cultivo control (PUFAs: 47%, EPA: 4% y DHA: 4.7% y superiores al de las pastas floculadas. Las pastas obtenidas por centrifugación indujeron un crecimiento del rotífero igual al obtenido con el alimento control (densidad máxima: 320rotíferos/mL; tasa instantánea de crecimiento: 0.23rotíferos/día, fecundidad: 1.49huevos/ hembra y productividad: 43x103rotíferos/L/día. Se concluye que la pasta de R. salina centrifugada y congelada a -20°C, durante cuatro semanas, sin adición de vitamina C, mantiene su calidad nutricional similar a la del alga fresca y puede ser usada como alimento de Brachionus plicatilis.Rhodomonas salina (Cryptophyta pastes as feed for Brachionus plicatilis (Rotifera. Rotifers are an important live feed for first feeding larvae of many fish species. The use of concentrated algae cells in the mass culture of the rotifer Brachionus plicatilis (Brachionidae has opened new horizons for research on this organism. Pastes of Rhodomonas salina (Pyrenomonadaceae obtained either by centrifugation or flocculation with chitosan were preserved, with or without vitamin C, at -20°C for four weeks and were evaluated

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

    Directory of Open Access Journals (Sweden)

    Bhushan Kumar Sharma

    2014-12-01

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

  12. An introduction to loricifera, cycliophora, and micrognathozoa.

    Science.gov (United States)

    Kristensen, Reinhardt Møbjerg

    2002-07-01

    Loriciferans, cycliophorans and micrognathozoans are amongst the latest groups of animals to be discovered. Other than all being microscopic, they have very different body plans and are not closely related. Loriciferans were originally assigned to the Aschelminthes. However, both new molecular and ultrastructural researches have shown that Aschelminthes consist of two unrelated groups, Cycloneuralia and Gnathifera. Cycloneuralia may be included in the Ecdysozoa, including all molting invertebrates, and Gnathifera are more closely related to Platyhelminthes. The phylum Loricifera shares many apomorphic characters (e.g., scalids on the introvert) with both Priapulida and Kinorhyncha, and can be included in the taxon Scalidophora, a subgroup of Cycloneuralia. Cycliophora was originally allied to the Entoprocta and Ectoprocta (Bryozoa) based on ultrastructual research. Subsequent molecular data show they may be related to Rotifera and Acanthocephala, within the taxon Gnathifera. The phylogenetic position of Cycliophora is therefore not settled, and more ultrastructural and molecular data are needed. Micrognathozoa is the most recent major group of animals to be described. They show strong affinities with both Rotifera and Gnathostomulida (within the taxon Gnathifera), especially in the fine structure of the pharyngeal apparatus, where the jaw elements have cuticular rods with osmiophilic cores. Furthermore the micrognathozoans have two rows of multiciliated cells that form a locomotory organ, similar to that seen in some gastrotrichs and interstitial annelids. This character is never seen in Rotifera or in the monociliated Gnathostomulida. Rotifera and Acanthocephala always have a syncytial epidermis (Syndermata). Micrognathozoa lack this characteristic feature. Therefore, they are postulated to be placed basally in the Gnathifera, either as a sister-group to Gnathostomulida or as a sister-group to Rotifera + Acanthocephala.

  13. A method for efficient extraction of rotifers (Rotifera) from soils

    Czech Academy of Sciences Publication Activity Database

    Devetter, Miloslav

    2010-01-01

    Roč. 53, č. 2 (2010), s. 115-118 ISSN 0031-4056 R&D Projects: GA ČR(CZ) GP206/06/P405 Institutional research plan: CEZ:AV0Z60660521 Keywords : soil rotifers * Bdelloids * quantitative extraction Subject RIV: EH - Ecology, Behaviour Impact factor: 1.474, year: 2010

  14. 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, even at synonymous positions, suggests that the repeats are kept nearly identical through a process of concerted evolution. Information-rich molecules like surface glycoproteins are well adapted for chemical communication and aquatic animals may have evolved signaling systems based on these compounds, whereas insects use cuticular hydrocarbons. Conclusion Owing to its critical role in mating, the mate recognition pheromone gene will be a useful molecular marker for exploring the mechanisms and rates of selection and the evolution of reproductive isolation and speciation using rotifers as a model system. The phylogenetic variation in the mate recognition pheromone gene can now be studied in conjunction with the large amount of ecological and population genetic data being gathered for the Brachionus plicatilis species complex to understand better the evolutionary drivers of cryptic speciation.

  15. Composition and abundance of rotifera in Ikpoba river, Benin, Edo ...

    African Journals Online (AJOL)

    The present study investigated some selected physico-chemical parameters and the composition and abundance of rotifers in Ikpoba River from June to November 2009 to ascertain its ecological status due to the increasing anthropogenic activities on the river using rotifers. Water and zooplankton samples were collected ...

  16. The Rotifera Fauna Of Gongola River Basin, Northeast Nigeria ...

    African Journals Online (AJOL)

    This study was undertaken to characterize the taxa composition, distribution pattern and the abundance of rotifers in surface waterbodies in the Gongola basin of Nigeria, West Africa. It was based on the analysis of net zooplankton samples collected from the River Gongola, its flow-through reservoirs, borrow-pit ponds and ...

  17. Age-related environmental gradients influence invertebrate distribution in the Prince Charles Mountains, East Antarctica

    Science.gov (United States)

    White, Duanne; Clarke, Laurence; McKay, Alan; Cooper, Alan; Stevens, Mark I.

    2016-01-01

    The potential impact of environmental change on terrestrial Antarctic ecosystems can be explored by inspecting biodiversity patterns across large-scale gradients. Unfortunately, morphology-based surveys of Antarctic invertebrates are time-consuming and limited by the cryptic nature of many taxa. We used biodiversity information derived from high-throughput sequencing (HTS) to elucidate the relationship between soil properties and invertebrate biodiversity in the Prince Charles Mountains, East Antarctica. Across 136 analysed soil samples collected from Mount Menzies, Mawson Escarpment and Lake Terrasovoje, we found invertebrate distribution in the Prince Charles Mountains significantly influenced by soil salinity and/or sulfur content. Phyla Tardigrada and Arachnida occurred predominantly in low-salinity substrates with abundant nutrients, whereas Bdelloidea (Rotifera) and Chromadorea (Nematoda) were more common in highly saline substrates. A significant correlation between invertebrate occurrence, soil salinity and time since deglaciation indicates that terrain age indirectly influences Antarctic terrestrial biodiversity, with more recently deglaciated areas supporting greater diversity. Our study demonstrates the value of HTS metabarcoding to investigate environmental constraints on inconspicuous soil biodiversity across large spatial scales. PMID:28083092

  18. Freshwater toxicity testing using rehydrated Philodina sp. (Rotifera) as test animals.

    Science.gov (United States)

    Snell, Terry W; Johnston, Rachel K; Matthews, Amelia B

    2017-10-01

    Rotifers have become widely used in aquatic toxicology as a rapid screening test for toxicity. The commercial availability of diapausing embryos (cysts) have facilitated their popularity because test animals can be obtained without having to master the details of culturing. Other rotifer species have life stages capable of surviving desiccation and also could be used in non-culture systems for toxicity assessment. In this article, we describe a system for toxicity testing in freshwater based on rehydrating desiccated bdelloid rotifers in the genus Philodina. These animals can remain in this anhydrobiotic state for more than one year and then rehydrate within hours to provide animals for toxicity tests. We describe three endpoints: a 1.5 h ingestion test, a 24 h mortality test, and a five day reproductive test. The latter test requires feeding and a method using a dried commercial product is explained. Using desiccated rotifers and dried food in toxicity tests make this system especially attractive because of its flexibility and low threshold of biological expertise required to execute the tests. The use of the Philodina toxicity test is illustrated with four metals: copper, lead, mercury and cadmium. Reproduction generally was the most sensitive endpoint, with EC50s of 0.33, 0.44, 0.60, and 0.12 mg/L, respectively. Ingestion was a close second with EC50s of 0.13, 1.64, 0.64, and 6.26 mg/L, respectively. © 2017 Wiley Periodicals, Inc.

  19. Pastas de Rhodomonas salina (Cryptophyta como alimento para Brachionus plicatilis (Rotifera

    Directory of Open Access Journals (Sweden)

    Miguel Guevara

    2011-12-01

    Full Text Available Pastas de Rhodomonas salina, obtenidas mediante centrifugación y floculación con quitosano y preservadas con o sin vitamina C, a -20°C fueron evaluadas bioquímicamente y proporcionadas como alimento al rotífero Brachionus plicatilis. Las pastas microalgales: (1 centrifugada y con vitamina C (CV, (2 centrifugada y sin vitamina C (C, (3 floculada y con vitamina C (FV y (4 floculada y sin adición de vitamina C (F; mantuvieron sus contenidos de proteínas y lípidos totales similares al cultivo control, con valores de 40.0±2.32% y 12.0±1.45%, respectivamente. La relación feofitina a/clorofila a fue similar (0.09-0.11 entre las pastas centrifugadas y el cultivo control, pero mayor en las pastas floculadas (1.28-1.48. Las pastas centrifugadas presentaron porcentajes de PUFAs totales, EPA y DHA similares al cultivo control (PUFAs: 47%, EPA: 4% y DHA: 4.7% y superiores al de las pastas floculadas. Las pastas obtenidas por centrifugación indujeron un crecimiento del rotífero igual al obtenido con el alimento control (densidad máxima: 320rotíferos/mL; tasa instantánea de crecimiento: 0.23rotíferos/día, fecundidad: 1.49huevos/ hembra y productividad: 43x103rotíferos/L/día. Se concluye que la pasta de R. salina centrifugada y congelada a -20°C, durante cuatro semanas, sin adición de vitamina C, mantiene su calidad nutricional similar a la del alga fresca y puede ser usada como alimento de Brachionus plicatilis.

  20. Freshwater rotifera of the genus Lucane of small water bodies in ...

    African Journals Online (AJOL)

    African Journal of Tropical Hydrobiology and Fisheries. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 9, No 1 (2000) >. Log in or Register to get access to full text downloads.

  1. The diversity of Indian Brachionidae (Rotifera: Eurotatoria: Monogononta and their distribution

    Directory of Open Access Journals (Sweden)

    B.K. Sharma

    2014-11-01

    Full Text Available We evaluate diversity status of the Brachionidae of India and present an annotated checklist of 46 species excluding dubious and unconfirmed reports. These merit biodiversity value as ~27% of the global diversity of the taxon and ~81% of its Oriental species. We observed two Australasian elements, two Oriental endemics, one Indian endemic, one paleotropical and one cosmo (sub tropical species. The cold-water Keratella serrulata and Notholca squamula are new records from eastern Himalayas. Maximum brachionid diversity (32 species from Assam state of northeast India (NEI is followed by the reports of 27 and 26 species from Tamil Nadu and West Bengal, respectively; 25 species each from Tripura and Maharashtra; and 24 species from Jammu & Kashmir. Brachionus, the most diverse brachionid genus, is widely distributed in India with low richness in hill states of NEI and coastal waters in particular. The Indian brachionid taxonomy is confounded with unconfirmed reports, misidentifications, invalid taxa, and inconsistent treatment of morphological variants, while analysis of cryptic diversity in Brachionus calyciflorus, B. caudatus, B. forficula, B. plicatilis, B. quadridentatus, B. urceolaris, Keratella cochlearis and K. quadrata species-groups awaits attention.

  2. Multigenerational effects of triclosan on the demography of Plationus patulus and Brachionus havanaensis (ROTIFERA).

    Science.gov (United States)

    González-Pérez, Brenda Karen; Sarma, S S S; Castellanos-Páez, M E; Nandini, S

    2018-01-01

    Triclosan is a personal care product widely used in North America, Europe and Asia as antimicrobial ingredient in many consumer chemical products. In Mexico concentrations of triclosan have been reported in aquatic systems. However, there is no law regulating the presence of chemicals such as triclosan, in aquatic systems. The scarce data about this chemical has increased concern among ecotoxicologists regarding possible effects on aquatic organisms. Moreover, multigenerational studies are rarely studied and the results vary depending on the contaminant. Rotifers, are a dominant group of zooplankton, and have been used in aquatic risk assessments of personal care products due to their sensitivity and high reproductive rates. Plationus patulus and Brachionus havanaensis are common rotifers distributed in aquatic ecosystems of Mexico and have been used in ecotoxicological bioassays. In this study, the median lethal concentration (LC50, 24h) of P. patulus and B. havanaensis exposed to triclosan was determined. Based on the LC50, we tested three sublethal concentrations of triclosan to quantify the demographic responses of both rotifers for two successive generations (F0, and F1). The 24h LC50 of triclosan for P. patulus and B. havanaensis were 300 and 500µgL -1 respectively. Despite the concentration, triclosan had an adverse effect on both Plationus patulus and Brachionus havanaensis in both generations exposed. Experiments show that P. patulus was more sensitive than B. havanaensis when exposed to triclosan. When exposed to triclosan the parental generation (F0) of P. patulus was far more affected than F1. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Reduced expression of exocytotic proteins caused by anti-cholinesterase pesticides in Brachionus calyciflorus (Rotifera: Monogononta

    Directory of Open Access Journals (Sweden)

    IA Pérez-Legaspi

    Full Text Available AbstractThe organophosphate and carbamate pesticides methyl-parathion and carbaryl have a common action mechanism: they inhibit acetylcholinesterase enzyme by blocking the transmission of nerve impulses. However, they can alter the expression of exocytotic membrane proteins (SNARE, by modifying release of neurotransmitters and other substances. This study evaluated the adverse effects of the pesticides methyl-parathion and carbaryl on expression of SNARE proteins: Syntaxin-1, Syntaxin-4 and SNAP-23 in freshwater rotifer Brachionus calyciflorus. Protein expression of these three proteins was analyzed before and after exposure to these two pesticides by Western Blot. The expression of Syntaxin-1, Syntaxin-4 and SNAP-23 proteins in B. calyciflorussignificantly decreases with increasing concentration of either pesticides. This suggests that organophosphates and carbamates have adverse effects on expression of membrane proteins of exocytosis by altering the recognition, docking and fusion of presynaptic and vesicular membranes involved in exocytosis of neurotransmitters. Our results demonstrate that the neurotoxic effect of anticholinesterase pesticides influences the interaction of syntaxins and SNAP-25 and the proper assembly of the SNARE complex.

  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 marker MitoTracker and lysosome activity using LysoTracker. Treatment of rotifers with JNK inhibitor enhanced mitochondria activity nearly 3-fold, whereas rapamycin treatment had no significant effect. Treatment of rotifers with rapamycin or JNK inhibitor reduced lysosome activity in 1, 3 and 8 day old animals, but treatment with both inhibitors did not produce any additive effect. We conclude that inhibition of TOR and JNK pathways significantly extends the lifespan of B. manjavacas. These pathways interact so that inhibition of both simultaneously acts additively to extend rotifer lifespan more than the inhibition of either alone. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

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

    International Nuclear Information System (INIS)

    Alvarado-Flores, Jesús; Rico-Martínez, Roberto; Ventura-Juárez, Javier; Silva-Briano, Marcelo; Rubio-Franchini, Isidoro

    2012-01-01

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

  6. 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.

  7. Multitasking of the piRNA Silencing Machinery: Targeting Transposable Elements and Foreign Genes in the Bdelloid Rotifer Adineta vaga.

    Science.gov (United States)

    Rodriguez, Fernando; Arkhipova, Irina R

    2016-05-01

    RNA-mediated silencing processes play a key role in silencing of transposable elements, especially in the germ line, where piwi-interacting RNAs (piRNAs) are responsible for suppressing transposon mobility and maintaining genome integrity. We previously reported that the genome of Adineta vaga, the first sequenced representative of the phylum Rotifera (class Bdelloidea), is characterized by massive levels of horizontal gene transfer, by unusually low transposon content, and by highly diversified RNA-mediated silencing machinery. Here, we investigate genome-wide distribution of pi-like small RNAs, which in A. vaga are 25-31 nucleotides in length and have a strong 5'-uridine bias, while lacking ping-pong amplification signatures. In agreement with expectations, 71% of mapped reads corresponded to annotated transposons, with 93% of these reads being in the antisense orientation. Unexpectedly, a significant fraction of piRNAs originate from predicted coding regions corresponding to genes of putatively foreign origin. The distribution of piRNAs across foreign genes is not biased toward 3'-UTRs, instead resembling transposons in uniform distribution pattern throughout the gene body, and in predominantly antisense orientation. We also find that genes with small RNA coverage, including a number of genes of metazoan origin, are characterized by higher occurrence of telomeric repeats in the surrounding genomic regions, and by higher density of transposons in the vicinity, which have the potential to promote antisense transcription. Our findings highlight the complex interplay between RNA-based silencing processes and acquisition of genes at the genome periphery, which can result either in their loss or eventual domestication and integration into the host genome. Copyright © 2016 by the Genetics Society of America.

  8. Population dynamics of Brachionus calyciflorus (Rotifera: Brachionidae in waste water from food-processing industry in Mexico

    Directory of Open Access Journals (Sweden)

    Raymundo Alfredo Arévalo Stevenson

    1998-09-01

    Full Text Available Waste water from Mexico's largest food processing industrial sector (based on maize, nejayote water was used for growing Brachionus calyciflorus isolated from Lake Chapultepec in the Federal District of Mexico (D.F.. Nejayote water was collected from Colonia Providencia, D.F. Experiments were conducted at 25°C in 25 ml capacity vials with 20 ml of medium into which we introduced B. calyciflorus at an initial density of 1 ind ml-1. The experimental design consisted a total of 33 test vessels (2 food combinations X 5 densities X 3 replicates = 30 plus 3 replicates as controls that contained only algae. Experiments were terminated after day 16. Waste water in original concentration did nt rotifes. However, when diluted to 5 oncentrations (ranging from 2% to 32% and pH adjusted to 7.0, rotifer density increased with increasing concentration of waste water. Green algae (at constant density of 2 X 10 6 cells-1 of Chlorella in combination with waste water resulted in a higher abundance of rotifers only at higher concentration (above 8 % of waste water. The maximum peak density of rotifers (238-50 ind ml -1 was obtained at 16% dilution of waste water nd with addition of Chlorella. The rate of population increase per day ® (mean-SD varied from 0.355-0.059 to 0.457-0.048 depending on food combination and concetration.Se usó aguas de desecho de la industria de la masa y la tortilla (aguas de nixtamal o nejayote para crecer rotíferos de agua dulce, Brachionus calyciflorus. El nejayote sin dilución no permitió el desarrollo del rotífero. Sin embargo, cuando se diluyó, B. calyciflorus aprovechó la materia orgánica. El agua de desecho por sí misma (sin alimento algal adicional fue comparable al agua con densidades del alga Chlorella de 2 X 10(6 células ml-1. Concentraciones de nejayote por encima del 8% no permitieron el crecimiento poblacional. Sin embargo, la presencia de alga permitió el desarrollo del rotífero a concentraciones de 8% y 16%. Nuestros hallazgos indican que el nejayote puedo ser utilizado de manera efectiva para la producción de rotíferos a gran escala para la acuacultura.

  9. Effect of three food types on the population growth of Brachionus calyciflorus and Brachionus patulus (Rotifera: Brachionidae

    Directory of Open Access Journals (Sweden)

    S.S.S. Sarma

    2001-03-01

    Full Text Available We compared the population growth of B. calyciflorus and B. patulus using the green alga Chlorella vulgaris, baker’s yeast Saccharomyces cerevisiae or their mixture in equal proportions as food. Food was offered once every 24 h in two concentrations (low: 1x10(6 and high: 3x10(6 ind. ml-1 separately for each species. The experiments were terminated after 15 days. In general, at any food type or concentration, B. patulus reached a higher population density. A diet of Chlorella alone supported a higher population growth of both rotifer species than yeast alone. B. calyciflorus and B. patulus achieved highest population densities (103+8 ind. ml-1 and 296+20 ind. ml-1, respectively on a diet of Chlorella at 3x10(6 ind. ml-1. When cultured using the mixture of Chlorella and yeast, the maximal population densities of B. calyciflorus were lower than those grown on Chlorella. Under similar conditions, the maximal abundance values of B. patulus were comparable in both food types. Regardless of food type and density the rate of population increase per day (r for B. calyciflorus varied from 0.13+0.03 to 0.63+0.04. These values for B. patulus ranged from 0.19+0.01 to 0.37+0.01. The results indicated that even though Chlorella was a superior foof for the tested rotifers, yeast can be effectively used at low concentrations to supplement algal requirements in rotifer culture systems.Se comparó el crecimiento poblacional de dos especies planctónicas (B. calyciflorus y B. patulus desarrolladas con el alga verde Chlorella vulgaris, la levadura de cerveza Saccharomyces cerevisiae y la mezcla de ambas dietas en proporciones iguales. B. patulus alcanzó las mayores densidades con cualquier tipo de alimento utilizado en comparación con B. calyciflorus. La dieta a base de Chlorella vulgaris sola promovió el mayor crecimiento poblacional en relación con la dieta de levadura sola. B. calyciflorus y B. patulus alcanzaron las mayores densidades de 103+8 ind. ml-1 y 296+20 ind. ml-1, respectivamente, con la dieta de Chlorella en 3x10(6 células ml-1. En condiciones similares, los valores máximos de abundancia de B. patulus fueron semejantes para ambos tipos de alimento. La tasa de incremento poblacional por día (r para B. calyciflorus vario de 0.13+0.03 a 0.63+0.04, sin importar el tipo y densidad de alimento. Los resultados indican que la dieta a base de Chlorella fue mejor para los rotíferos considerados, y que la levadura puede usarse de manera efectiva a concentraciones bajas para complementar los requerimientos algales del sistema de cultivo de rotíferos.

  10. Acidification experiments in conifer forest. 8. Effects of acidification and liming on some soil animals: protozoa, rotifera, and nematoda

    Energy Technology Data Exchange (ETDEWEB)

    Stachurska-Hagen, T.

    1980-01-01

    Samples were taken from young stands of Pinus sylvestris L. (0.5 m). Some of the experimental plots underwent liming with CaCO/sub 3/ equalling 500 and 4,500 kg of CaO per ha, and subsequent monthly watering with 50 mm of ground water (pH6). Other plots obtained monthly artificial precipitation with 50 mm water of pH 6 (ground water), 4, 3, 2.5 and 2 respectively. Five soil samples (each 2.6 cm of diameter) were taken randomly from each experimental plot on October 24, 1978. Only the top layer consisting of litter and humus was taken for further processing. Soil moisture and pH value were determined as were numbers of testaceans, ciliates, nematodes and rotifers. Data show that all studied groups of microfauna became less numerous under acidification. Reduction of microfaunal abundance seems to result from reduction of bacterial populations which serve as food, and elimination of mosses which provide living space. Liming reduced numbers of testaceans, rotifers and nematodes; ciliates were not affected. 26 references, 7 figures, 1 table.

  11. Combined effects of temperature and lead concentration on the competition between the rotifers Brachionus havanaensis and Brachionus rubens (Rotifera: Brachionidae).

    Science.gov (United States)

    Montúfar-Meléndez, Aramen Iván; Sánchez-Ortíz, Jonathan Raúl; Sarma, S S S; Nandini, S

    2007-02-15

    The combined effects of temperature (22 and 32 degrees C) and the concentration of Pb (0, 0.05, 0.1 and 0.2 mg L- 1) on the competition between B. havanaensis and B. rubens using population growth was evaluated. At 22 degrees C, increase in Pb concentration had little effect on the population growth of B. havanaensis, while it had adverse effect on B. rubens. At this temperature, the presence of B. rubens had adversely affected the growth of B. havananensis. However, under similar conditions, B. rubens was not influenced by B. havanaensis. Increase in Pb concentration decreased the population growth of B. havanaensis at 32 degrees C regardless whether the population was alone or together with B. rubens. When grown alone, B. havanaensis was numerically more abundant than B. rubens. B. havanaensis grown at 32 degrees C had population growth rates of 0.32 to 0.56 day- 1, depending on Pb level and the presence of competitor. At this temperature, B. rubens had mostly negative growth rates. Further, our study showed that Pb at a concentration as low as 0.05 mg L- 1 had adverse effect on B. rubens at both the temperatures. Though B. rubens is known to occur naturally at wide temperature range, in our study this species appeared to have adapted to low temperature.

  12. Effect of different densities of live and dead Chlorella vulgaris on the population growth of rotifers Brachionus calyciflorus and Brachionus patulus (Rotifera

    Directory of Open Access Journals (Sweden)

    E. Lucía-Pavón

    2001-12-01

    Full Text Available In order to maintain rotifer populations during periods of low algal production, it is necessary to offer alternate diets, some of which include forms of preserved algae. The present work is based on the effect of live and dead Chlorella vulgaris on the population growth of Brachionus calyciflorus and Brachionus patulus. The experimental design consisted of 3 algal levels (0.5x10(6, 1.5x10(6 and 4.5x10(6 cells ml-1 offered in 3 forms (living, frozen and heat-killed. The maximal population density values for B. calyciflorus ranged from 55±1 ind. ml-1 (at 0.5x10(6 cells ml-1 to 471±72 ind. ml-1 (at 4.5x10(6 cells ml-1 with live Chlorella, but was much lower (6±1 to 26±6 ind. ml-1 with frozen or heat-killed alga under comparable food levels. However, the maximum population density of B. patulus under live or or heat-killed Chlorella was similar at comparable algal levels but when offered frozen algae it was four times less. The highest mean peak population density was 1227±83 ind. ml-1 under 4.5x10(6 cells ml-1. The rate of population increase for B. calyciflorus varied from 0.50 to 0.79 using live Chlorella, but under comparable conditions, this range was lower (0.21 to 0.31 for B. patulus. Results have been discussed in light of possible application for aquaculturePara mantener poblaciones de rotíferos durante periodos con escasez de microalgas, es necesario ofrecer dietas alternativas, incluyendo algunas formas de microalgas preservadas. El presente trabajo analiza el efecto de Chlorella vulgaris viva y muerta sobre el crecimiento poblacional de Brachionus calyciflorus y Brachonus patulus. El diseño experimental consistió en tres niveles de algas (0.5x10(6, 1.5x10(6 y 4.5x10(6 células ml-1 ofrecidas en tres formas (viva, congelada y muerta con agua caliente. Las abundancias máximas de población de B. calyciflorus variaron desde 55±1 ind. ml-1 (en 0.5x10(6 células ml-1 a 471±72 ind. ml-1 (en 4.5x10(6 células ml-1 con Chlorella viva, mientras que, cuando se utilizó alga congelada o muerta con agua caliente, la abundancia fue mucho menor (6±1 a 26±6 ind. ml-1. Sin embargo, la máxima densidad de población de B. patulus con Chlorella viva o muerta con calor fue similar bajo niveles de algas comparables, mientras que cuando se ofreció alga congelada, la abundancia fue cuatro veces menor. La abundancia máxima de B. patulus fue 1 227±83 ind. ml-1 bajo 4.5x10(6 células ml-1. La tasa de crecimiento poblacional de B. calyciflorus varió desde 0.50 hasta 0.79 usando Chlorella viva, pero bajo las mismas condiciones, el rango es menor (0.21 a 0.31 para B. patulus. Los resultados se discuten para su posible aplicación en la acuacultura

  13. Combined effect of concentrations of algal food (Chlorella vulgaris and salt (sodium chloride on the population growth of Brachionus calyciflorus and Brachionus patulus (Rotifera

    Directory of Open Access Journals (Sweden)

    Víctor M. Peredo-Álvarez

    2003-06-01

    Full Text Available Salinity is an important variable influencing the density and diversity of rotifers. Studies on salt tolerance of rotifers have so far concentrated on euryhaline species while very little information is available on noneuryhaline taxa. In the present work, we have evaluated the combined effects of Chlorella vulgaris and sodium chloride on the population growth of two freshwater rotifers B. calyciflorus and B. patulus. A 24 hr acute tolerance test using NaCl revealed that B. calyciflorus was more resistant (LC50 = 3.75 ± 0.04 g l-1 than B. patulus (2.14 ± 0.09 g l-1 . The maximal population density (mean±standard error for B. calyciflorus in the control at 4.5 X10 6 cells ml-1 (algal level was 80 ±5 ind. ml-1 , which was nearly a fifth of the one for B. patulus (397 ± 7 ind. ml-1 under comparable conditions. Data on population growth revealed that regardless of salt concentration, the density of B. calyciflorus increased with increasing food levels, while for B. patulus, this trend was evident only in the controls. Regardless of salt concentration and algal food level, the day of maximal population density was lower (4 ± 0.5 days for B. calyciflorus than for B. patulus (11 ±1 day. The highest rates of population increase (r values for B. calyciflorus and B. patulus were 0.429 ± 0.012 and 0.367 ± 0.004, respectively, recorded at 4.5 X10(6 cells ml-1 of Chlorella in the controls. The protective role of algae in reducing the effect of salt stress was more evident in B. calyciflorus than B. patulus.La salinidad es una variable importante que tiene influencia sobre la densidad y la diversidad de los rotíferos. Los estudios de rotíferos sobre tolerancia a la sal que se tienen hasta ahora se han concentrado en especies eurihalinas, sin embargo, hay muy poca información sobre taxas no eurihalinos. En el presente trabajo, se evaluaron los efectos combinados de las concentraciones de Chlorella vulgaris y cloruro de sodio sobre el crecimiento poblacional de dos rotíferos de agua dulce, B. calyciflorus y B. patulus. Una prueba de toxicidad aguda de 24 h utilizando cloruro de sodio reveló que B. calyciflorus fue más resistente (CL50 = 3.75 ± 0.04 g l -1 que B. patulus (2.14 ± 0.09 g l-1 . La máxima densidad de población (media ± error estándar de B. calyciflorus en el lote control, utilizando una concentración 4.5 X10(6 células ml-1 de alga fue de 80 ± 5 ind. ml-1 , casi una quinta parte de B. patulus (397 ±7 ind. ml-1 sobre condiciones comparables. Datos sobre el crecimiento poblacional revelaron que cualquier concentración de sal carece de efecto, la densidad de B. calyciflorus se incrementa cuando aumentan los niveles de alimento. Sin embargo para B. patulus esta tendencia fue evidente únicamente en los controles. Independientemente de las concentraciones de sal y los niveles de alimento, el día de abundancia máxima fue menor para B. calyciflorus (4 ± 0.5 días que para B. patulus (11 ±1 días. Los valores de la máxima tasa de crecimiento poblacional (r fueron para B. calyciflorus y B. patulus de 0.429 ± 0.012 y 0.367 ± 0.004, respectivamente en lotes control con 4.5 X10(6 células ml-1 de Chlorella. El papel de protección de alga para reducir el efecto del estrés de la sal fue más evidente en B. calyciflorus que en B. patulus.

  14. Immunodetection of Luteinizing Hormone (LH, Follicle-Stimulating Hormone (FSH, Thyroid Stimulating Hormone (TSH and Prolactin (PRL in Brachionus calyciflorus (Rotifera: Monogononta

    Directory of Open Access Journals (Sweden)

    Jesús Alvarado-Flores

    2009-12-01

    Full Text Available The endocrine system controls and coordinates behavioral, biochemical, and physiological processes through signal mechanisms using neuropeptides or products of neurosecretory cells. Among invertebrates, this system is poorly studied in rotifers, in which estrogens and androgens significantly affect sexual reproduction. This is the first report of the presence of the Luteinizing Hormone (LH, Follicle-Stimulating Hormone (FSH, Thyroid Stimulating Hormone (TSH and Prolactin (PRL in rotifers. Analyses included the avidin-biotin-peroxidase complex method with primary antibodies LH (Anti-Rat LH serum for RIA, PRL (Anti-Rat PRL serum for RIA, FSH (Anti-Rat FSH serum for RIA and TSH (Anti-Rat TSH serum for RIA. These hormones were found in females, males and parthenogenetic and sexual eggs of the freshwater Brachionus calyciflorus. The immunoreactivity of FSH, LH, TSH and PRL in females was observed in: ovaries, cerebrum, mastax, stomach, lorica, and the stomach gland. However, in males LH was observed only at the trochal disk and cerebrum. The hormones FSH, TSH and PRL, were observed in testicles, contractil vesicles, and cementary gland of males. Regarding amictic or parthenogenetic eggs, the hormones LH, FSH, TSH, and PRL were located mainly in the micromeres, and the staining in the macromeres was weak. On the other hand, in the mictic or sexual eggs the inner shell is stained for the hormones PRL and LH, opposite to the staining of FSH and TSH, located mainly in the embryo. In general, immuno-reactivity was observed in areas important for the reproductive, excretory, digestive and developmental processes. Rev. Biol. Trop. 57 (4: 1049-1058. Epub 2009 December 01.Se logró detectar la presencia de las hormonas: Hormona Luteinizante (LH, Hormona Folículo Estimulante (FSH, Hormona Estimulante de la Tiroides (TSH y Prolactina (PRL en Brachionus calyciflorus siendo el primer reporte de la presencia de dichas hormonas en rotíferos. Estas hormonas fueron identificadas por un método inmunológico-histológico-químico usando el complejo avidina-biotina- peroxidasa con los siguientes anticuerpos primarios: LH (Anti-Rata LH suero para RIA, PRL (Anti-Rata PRL suero para RIA, FSH (Anti-Rata FSH suero para RIA y TSH (Anti-Rata TSH en suero para RIA. Estas hormonas se encontraron en las hembras, machos, huevos partenogenéticos y huevos sexuales del rotífero dulceacuícola B. calyciflorus. La reactividad inmunológica de FSH, LH, PRL y TSH en las hembras se observó en ovarios, cerebro, mástax, estómago, lorica, y la glándula del estómago. Sin embargo, en machos, la LH se observó sólo en el disco trocal y cerebro mientras que las hormonas FSH, PRL y TSH, se observaron en testículos, vesícula contráctil, y la glándula cementaria. En cuanto a los huevos partenogenéticos o amícticos, las hormonas LH, FSH, TSH, y PRL, se encontraron principalmente en los micrómeros, y en los macrómeros la tinción es débil. Por otra parte, el huevo sexual o míctico muestra reactividad inmunológica en la cubierta interior del huevo para las hormonas LH y PRL, lo contrario para FSH y TSH, las cuales se observaron principalmente en el embrión. La reactividad inmunológica fue observada, en general, en áreas importantes para los procesos reproductivos, excretorios, digestivos y del desarrollo.

  15. Brachionidae (Rotifera: Monogononta de la albufera El Paraíso y el reporte de Brachionus ibericusen el Perú

    Directory of Open Access Journals (Sweden)

    Emily Toscano

    2013-12-01

    Full Text Available En este trabajo se reportan las especies de Brachionidae reconocidos en las muestras recogidas en octubre de 2010 en la albufera Laguna El Paraiso, Huacho (11°13' −11° 10'S, 77° 35' −77°40'W. Cinco especies fueron determinadas: Keratella tropica, Brachionus quadridentatus, B. urceolaris, B. angularis y B. ibericusCiros-Pérez 2001. Este último es un nuevo reporte para el Perú y amplía su distribución a nivel mundial.

  16. Untitled

    African Journals Online (AJOL)

    Biodiversity And Spatial Distribution of Rotifera in a Shallow Hypereutrophic. Tropical Lake (Cameroon). Togouet ... Key words : Rotifera, biodiversity, hypereutrophic lake, spatial distribution, tropical zone. RÉSUME. Une étude qualitative de la ...... knowledge of the Rotifera of Mexico. In: Gilbert J.J., Lubzens. E. & Miracles ...

  17. Antarctic bdelloid rotifers: diversity, endemism and evolution

    Czech Academy of Sciences Publication Activity Database

    Iakovenko, N. S.; Smykla, J.; Convey, P.; Kašparová, Eva; Kozeretska, I. A.; Trokhymets, V.; Dykyy, I.; Plewka, M.; Devetter, Miloslav; Duriš, Z.; Janko, Karel

    2015-01-01

    Roč. 761, č. 1 (2015), s. 5-43 ISSN 0018-8158 R&D Projects: GA AV ČR KJB600450903; GA MŠk(CZ) LM2010009 Institutional support: RVO:67985904 ; RVO:60077344 Keywords : Bdelloidea * DNA taxonomy * Molecular biogeography Subject RIV: EG - Zoology Impact factor: 2.051, year: 2015

  18. Elucidating the phylogenetic position of Gnathostomulida and first mitochondrial genomes of Gnathostomulida, Gastrotricha and Polycladida (Platyhelminthes).

    Science.gov (United States)

    Golombek, Anja; Tobergte, Sarah; Struck, Torsten H

    2015-05-01

    Gnathostomulida is a taxon of small marine worms, which exclusively inhabit the interstitium. The evolution of Gnathostomulida has been discussed for decades. Originally regarded as primitive animals with affinities to flatworms, the phylogenetic position of Gnathostomulida has been debated. Given the lack of an anus a close relationship to Platyhelminthes has been maintained (i.e., Plathelminthomorpha hypothesis). Alternative hypotheses proposed Gnathostomulida as being close to Gastrotricha due to the presence of a monociliary epidermis (i.e., Monokonta/Neotrichozoa hypothesis) or to Syndermata based on the complicated jaw apparatus (i.e., Gnathifera hypothesis). Molecular analyses using only few genes were inconclusive. Recent phylogenomic studies brought some progress by placing Gnathostomulida as sister to Syndermata, but support for this relationship was low and depended on the analytical strategy. Herein we present the first data of complete or nearly complete mitochondrial genomes for two gnathostomulids (Gnathostomula paradoxa &G. armata), one gastrotrich (Lepidodermella squamata) and one polyclad flatworm (Stylochoplana maculata) to address the uncertain phylogenetic affinity of Gnathostomulida. Our analyses found Gnathostomulida as sister to Syndermata (Gnathifera hypothesis). Thorough sensitivity analyses addressing taxon instability, branch length heterogeneity (also known as long branch attraction) and base composition heterogeneity showed that the position of Gnathostomulida is consistent across the different analyses and, hence, independent of potential misleading biases. Moreover, by ameliorating these different biases nodal support values could be increased to maximum values. Thus, our data support the hypothesis that the different jaw apparatuses of Syndermata and Gnathostomulida are indeed homologous structures as proposed by the Gnathifera hypothesis. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. 95 - 100_Akindele

    African Journals Online (AJOL)

    DR. AMINU

    2013-06-01

    -chemical water .... and magnesium ions (Goltermann et al., 1978). ..... this study feasible. REFERENCES. Akinbuwa, O. (1999): The rotifera fauna and physico- chemical condition of Erinle Lake and its major inflows at Ede, ...

  20. Feeding of Marbled Goby, Oxyeleotris marmorata (Blkr., Larvae in the Two Weeks of Their Early Life

    Directory of Open Access Journals (Sweden)

    Irzal Effendi

    2007-12-01

    Full Text Available ABSTRACTThe experiment was carried out at the Laboratory of Aquaculture System and Technology, Faculty of Fisheries, Institut Pertanian Bogor, Bogor. Factorial arrangement in randomised block design was used in this experiment with two factors: kind of feed and feed density for sand goby, Oxyeleotris marmorata (Blkr. larvae. There were 3 kinds of feed: rotifer, enriched-rotifer, and egg yolk-premix. Rotifer density of 20, 30, and 40 individuals/ml were maintained troughout the experiment. Egg yolk-premix were given per day in equivalent quantity as those rotifers in the treatment. Larvae of 40 individuals/l were kept in the 250 l plastic tanks, filled with 200 l of aerated ground water for 15 days indoor. Larvae fed rotifer showed better survival and growth rate than those fed egg yolk-premix. Increased rotifer density tended to increase survival and growth rate of larvae.Key words :  marbled goby, Oxyeleotris marmorata, larvae, feeding, rotifers ABSTRAKPercobaan ini dilakukan di Kolam Percobaan Babakan, Laboratorium Bogor, Bogor, dan dirancang berbentuk factorial dalam rancangan acak kelompok, dengan faktor: (1 jenis pakan dan (2 kepadatan pakan. Jenis pakan dibedakan menjadi: rotifera, rotifera-diperkaya, dan kuning telur-premiks, sedangkan kepadatan rotifera dibedakan menjadi : 20,30, dan 40 individu/ml, dipertahankan setiap hari. Kuning telur-premiks diberikan kepada larva ikan betutu, Oxyeleotris marmorata setiap hari yang setara dengan bobot rotifera setiap perlakuan, berdasarkan bobot kering keduanya. Larva sebanyak 40 ekor/l dipelihara dalam tangki plastik bervolume 250 l yang diisi air 200 l selama 15 hari dalam ruangan. Larva yang diberi rotifera cenderung memiliki kelangsungan hidup dan pertumbuhan lebih besar daripada kuning telur-premiks. Kepadatan rotifera yang semakin tinggi cenderung dapat meningkatkan kelangsungan hidup dan pertumbuhan larva.Kata kunci :  ikan betutu, Oxyeleotris marmorata, larva, pemberian pakan, rotifera

  1. ZOOPLANKTON FAUNA OF BİNGÖL FLOATING ISLANDS IN WINTER SEASON

    OpenAIRE

    Şen Özdemir, Nurgül; Caf, Fatma

    2015-01-01

    In this study was carried out winter season in 2011; zooplankton faunaof the Bingol Floating Islands. To­tally 18 zooplankton species were determinedas fol­lows; 14 Rotifera, 3 Cladocera and 1 Copepoda. It was determined thatthis zooplanktonic organisms consist­ed of 87.74 % Rotifera, 6.83 % Cladocera, and3.36 %  copepodit stages, 2.07 %  nauplii of copepoda. Rotif­era were thedominant group with regard to both spe­cies numbers, and individual numbers ofspecies. Cy­clops vicinus from Copepoda...

  2. Relationship between physicochemical parameters and ...

    African Journals Online (AJOL)

    Zooplankton samples were collected with silk plankton net of 25cm diameter of 70µm meshes attached with a bottle of 50ml capacity at the base and collection of samples of zooplanktons through vertical hauling.Five different groups of zooplankton were identified in this study where Rotifera group represented as the most ...

  3. Zooplankton composition of Van Lake Coastline in Turkey | Yildiz ...

    African Journals Online (AJOL)

    This study was completed with periodical surveys in coastal band of Van Lake between May and September in 2005 to 2006 period. It was carried out on a total of 20 sites selected as sampling points and having three distinct characteristics. During the study, a total of 20 species (14 belonged to genus of Rotifera, 4 to ...

  4. 87 - 90 Indabawa

    African Journals Online (AJOL)

    DR. AMIN

    number of individual with Euglena, Paramecium and. Chlamydomonas species respectively. From the analysis of variance Table 4. It was found that protozoans, cladocera, copepoda, and Rotifera showed highly significant difference between stations. (p≤0.05) and there was no significant difference between the months.

  5. Response of food organisms to inorganic nitrogen availability ...

    African Journals Online (AJOL)

    Influence of inorganic N2 forms on pond food organisms was investigated. Seven identified plankton taxa comprising four phytoplankton: Desmidiaceae (desmids), Bacillariophyceae (diatoms), Cyanophyceae (blue-green algae) and Chlorophyceae (green algae) and three zooplankton: Protozoa, Cladocera and Rotifera ...

  6. Author Details

    African Journals Online (AJOL)

    Foto, MS. Vol 6, No 2 (2006) - Articles Application of biological indices in the assessment of pollution in the Mfoundi River Basin (Cameroon) Abstract PDF · Vol 6, No 3 (2006) - Articles Biodiversity and spatial distribution of Rotifera in a shallow hyperuetrophic tropical Lake (Cameroon) Abstract PDF · AJOL African Journals ...

  7. Untitled

    Indian Academy of Sciences (India)

    Rice crop, nitrogen uptake, in the experiments with blue-green algae (Sahay), 223. Rice, spatial and temporal aspects of origin of (Nayar), 297. Rice, transplanted, photo-function of (Venkataraman), 145. Rotifera, responses of, to variations in some ecological factors (Arora), 57. Sphaerosyllis (Polychaeta), on a species of, ...

  8. The effect of some environmental factors on zooplankton community ...

    African Journals Online (AJOL)

    The zooplankton of Lake Qarun was studied January–December 2003. A total of 26 species was recorded, amongst which protozoa, primarily ciliophora, were most abundant (79% of the species total), followed by rotifera (13%) and copepoda (8%). The average density ranged from 965–1 452 l–1. The highest density (2 ...

  9. Taxa Composition, Abundance, Distribution And Diversity Of The ...

    African Journals Online (AJOL)

    Forty-eight genera of plankton were recorded; nine of Cyanophyceae, thirteen each of Chlorophyceae and Bacillariophyceae, seven of Protozoa and three each of Rotifera and Crustacea. Members of Cyanophyceae dominated the assemblage accounting for 91.77% of the total plankton abundance. All the major plankton ...

  10. Zooplankton composition and community structure in Lake Tiga ...

    African Journals Online (AJOL)

    Zooplankton in Lake Tiga was identified and its community structure assessed between March 2009 and March 2011. A total of 54 species of zooplankton was recorded, comprising two species of Protozoa, 26 species of Rotifera, eight species of Copepoda, 11 species of Cladocera, four species of Ostracoda and three ...

  11. Avaliação dos métodos de amostragem para fauna perifítica em macrófitas na Reserva da Biosfera, Serra do Espinhaço, Estado de Minas Gerais, Brasil - DOI: 10.4025/actascibiolsci.v30i3.377 Evaluation of sampling methods for periphytic fauna in macrophytes at the Espinhaço Mountain Range Biosphere Reserve, Minas Gerais State, Brazil - DOI: 10.4025/actascibiolsci.v30i3.377

    Directory of Open Access Journals (Sweden)

    Cristiane Machado López

    2008-10-01

    Full Text Available Os métodos “Jarra”, “Remocao Manual” e “Draga de Eckman modificada” foram avaliados para amostrar a fauna perifitica associada a macrofitas aquaticas. Foram coletadas 63 amostras em cinco ambientes lenticos e tres loticos na reserva da biosfera da Serra do Espinhaco (Estado de Minas Gerais, Brasil. Os testes estatisticos Anova e Tukey foram feitos para riqueza de Protista, Rotifera e Crustacea, enquanto para a abundancia de Protista, Rotifera, Crustacea, Gastrotricha, Tardigrada e Nematoda foram avaliados os percentuais. Os protozoarios e rotiferos representaram 80% da abundancia e riqueza da comunidade. Nos ecossistemas avaliados todos os metodos foram relevantes para Protista, por outro lado, o metodo da Jarra foi o mais adequado para a analise de Crustacea. Entre os metodos, a Draga foi menos indicada para os grupos de microinvertebrados nos ecossistemas aquaticos. Os metodos Remocao Manual e Draga foram apropriados para analisar Rotifera. A abundancia de Gastrotricha e Tardigrada demonstrou melhores resultados pelo metodo da Jarra e Nematoda pelo metodo da Draga. Os tres metodos sao apropriados para amostragem da fauna perifitica em ambos os sistemas aquaticos. Entretanto, e importante estar ciente de que para cada tipo de ecossistema a amostragem da comunidade faunistica requer um metodo especifico para obter a melhor performance.The methods “Jar”, “Manual Removal” and “modified Ekman`s Dredge” were evaluated for sampling periphyton fauna associated to aquatic macrophytes. Sixty three samples were collected from five lentic and three lotic water bodies at Espinhaço Mountain Range Biosphere Reserve (Minas Gerais, Brazil. ANOVA and Tukey statistical tests were performed for Protista, Rotifera and Crustacea richness, whilst Protista, Rotifera, Crustacea, Gastrotricha, Tardigrada and Nematoda, abundance were evaluate by percentage. Amongst the three methods, Dregde is less indicated for different water bodies systems

  12. Improvement of survival and development of Pacific white shrimp Litopenaeus vannamei larvae by feeding taurine enriched rotifers

    Directory of Open Access Journals (Sweden)

    Dedi Jusadi

    2015-03-01

    Full Text Available ABSTRACTThe objective of the present experiment was to study the most optimum taurine enrichment concentration of rotifers in improving Pacific white shrimp larva Litopenaeus vannamei survival and development. White shrimp larvae at sixth naupliar stage were reared in 12 units of 500 L fibre glass tanks with a stocking density of 125 ind/L. Starting from zoea two stage (Z-2, the larva was provided with rotifers with different taurine enrichment concentration according to the treatments, i.e. 0 mg/L enrichment medium (A, 25 mg/L (B, 50 mg/L(C, and 100 mg/L (D. The results show that different taurine concentration in the enrichment media increased taurine level in rotifers. Furthermore, the administration of taurine enriched rotifers up to 50 mg/L significantly improved larval survival and may accelerate larval development. The experimental results also concluded that a concentration of 50 mg/L is the most optimum taurine enrichment concentration of rotifers for the improvement of white shrimp larval survival and developmental stage.Keywords: taurine, rotifer, white shrimp, enrichmentABSTRAKPenelitian ini bertujuan untuk mengkaji konsentrasi optimum taurin melalui pengayaan pada rotifera terhadap tingkat kelangsungan hidup dan perkembangan stadia larva udang vaname Litopenaeus vannamei. Larva udang vaname stadia naupli-6 dipelihara dalam 12 tangki fiberglass volume 500 L dengan kepadatan 125 ind/L. Dimulai sejak stadia zoea 2 (Z-2 larva diberi rotifera yang diperkaya dengan taurin dengan konsentrasi yang berbeda sesuai dengan perlakuan, yaitu 0 mg/L media pengkaya (A, 25 mg/L (B, 50mg/L (C, dan 100mg/L (D. Hasil penelitian menunjukkan pengayaan taurin pada konsentrasi yang berbeda menyebabkan peningkatan kandungan taurin rotifera. Sementara pemberian rotifera yang diperkaya taurin hingga 50 mg/L meningkatkan kelangsungan hidup dan mempercepat perkembangan stadia larva udang. Berdasarkan hasil penelitian ini dapat disimpulkan bahwa pemberian

  13. Effect of Kind and Dosage of Enrichment Materials on the Nutritional Quality of Rotifers Especially n3-HUFA

    Directory of Open Access Journals (Sweden)

    Muhammad Agus Suprayudi

    2003-05-01

    Full Text Available This experiment was conducted to evaluate the quality of rotifer enriched with four  kinds of enrichement materials from the stand point of essensial fatty acids. Rotifer was enriched at 24 - 25oC for 18 hours at a density of 1000 ind/ml.  Rotifers were treated by four kinds of enrichment materials such as oleic acid (R-OA, two different density of Nannochloropsis oculata, (4x107 and 16x107 cell/ml; R-N18 and R-N42 two different levels of eicosapentaenoic acids (EPA triglyceride type (EPA-TAG (20 and 40 ml/ml; R-E20, R-E40 and two different level of EPA ethyl ester (EPA-EE (R-EE25 and R-EE50% respectively. Rotifers enriched with Nannochloropsis oculata and EPA-EE type have a similar profile of essensial fatty acid especially on n3-HUFA that dominated by EPA, while DHA was in a trace amount or not detected.  In addition Nannochloropsis oculata as an enrichment material showed the highest population density of rotifers during enrichment periods.  Rotifer enriched with EPA-TAG has a more complete of essential fatty acid profile compared to other enrichment materials due to their contained both of EPA and DHA. We conclude that rotifer enriched with EPA-TAG as enrichment material showed the best nutritional quality of rotifers from the stand point of essential fatty acid. Key words :  Rotifers, enrichment, eicosapentaenoic acid, docosaheksaenoic acid,  n3-HUFA   ABSTRAK Penelitian ini dilakukan untuk mengetahui profil asam lemak rotifera yang diperkaya dengan berbagai macam jenis dan dosis pengkaya. Rotifera dengan kepadatan 1000 ind./ml diperkaya dengan bebagai bahan pengkaya seperti asam oleat (R-OA; Nannochloropsis oculata dengan kepadatan 4x107 dan 16x107 sel/ml (R-N18 dan R-N42; eicosapentaenoic acid (EPA tipe triglicerida (EPA-TAG  dengan dosis 20 dan 40 μl (R-E20 dan R-E40 dan EPA tipe ethyl esther (EPA-EE  dengan dosis 25 dan 50 μl per liter (R-EE25 and R-EE50%. Rotifera diperkaya selama 18 jam pada suhu 24-25oC. Rotifera yang

  14. Zooplankton assemblage of Oyun Reservoir, Offa, Nigeria.

    Science.gov (United States)

    Mustapha, Moshood K

    2009-12-01

    The influence of physico-chemical properties of Oyun Reservoir, Offa, Nigeria (a shallow tropical African reservoir) on its zooplankton composition and abundance were investigated at three stations for two years between January 2002 and December 2003. Diversity is not high: only three groups of zooplankton were found: Rotifera with eight genera; and Cladocera and Copepoda with three genera each. Rotifera dominated numerically (71.02%), followed by Cladocera (16.45%) and Copepoda (12.53%). The zooplankton was more prevalent during the rainy season, and there were variations in the composition and abundance along the reservoir continuum. Factors such as temperature, nutrients, food availability, shape and hydrodynamics of the reservoir, as well as reproductive strategies of the organisms, strongly influence the generic composition and population density of zooplankton. Prevention of ecological deterioration of the water body would greatly should result in a more productive water body, rich in zooplankton and with better fisheries.

  15. On the phylogeny of the Metazoa in the light of Cycliophora and Micrognathozoa

    DEFF Research Database (Denmark)

    Sørensen, M.V.; Funch, P.; Willerslev, E.

    2000-01-01

    lamina. An earlier suggested close relationship between Cycliophora and Ectoprocta is rejected. The rotifer-like animal Micrognathozoa is placed in the clade Gnathifera, which also contains Gnathostomulida, Seisonida, Acanthocephala and Eurotatoria. Gnathifera is supported by the presence of jaws...... with a unique ultrastructure and cross-striated muscles attached to the jaw elements by epithelial cells. The jaws in Acanthocephala are considered secondarily reduced. In the analysis, Rotifera turns out to be paraphyletic with respect to Acanthocephala...

  16. On the phylogeny of the metazoa in the light of Cycliophora and Micrognathozoa

    DEFF Research Database (Denmark)

    Sorensen, M. V.; Funch, P.; Willerslev, E.

    2000-01-01

    lamina. An earlier suggested close relationship between Cycliophora and Ectoprocta is rejected. The rotifer-like animal Micrognathozoa is placed in the clade Gnathifera, which also contains Gnathostomulida, Seisonida, Acanthocephala and Eurotatoria. Gnathifera is supported by the presence of jaws...... with a unique ultrastructure and cross-striated muscles attached to the jaw elements by epithelial cells. The jaws in Acanthocephala are considered secondarily reduced. In the analysis, Rotifera turns out to be paraphyletic with respect to Acanthocephala....

  17. Acanthocephalan phylogeny and the evolution of parasitism.

    Science.gov (United States)

    Near, Thomas J

    2002-07-01

    The study of parasite evolution relies on the identification of free-living sister taxa of parasitic lineages. Most lineages of parasitic helminths are characterized by an amazing diversity of species that complicates the resolution of phylogenetic relationships. Acanthocephalans offer a potential model system to test various long-standing hypotheses and generalizations regarding the evolution of parasitism in metazoans. The entirely parasitic Acanthocephala have a diversity of species that is manageable with regards to constructing global phylogenetic hypotheses, exhibit variation in hosts and habitats, and are hypothesized to have close phylogenetic affinities to the predominately free-living Rotifera. In this paper, I review and test previous hypotheses of acanthocephalan phylogenetic relationships with analyses of the available 18S rRNA sequence database. Maximum-parsimony and maximum-likelihood inferred trees differ significantly with regard to relationships among acanthocephalans and rotifers. Maximum-parsimony analysis results in a paraphyletic Rotifera, placing a long-branched bdelloid rotifer as the sister taxon of Acanthocephala. Maximum-likelihood analysis results in a monophyletic Rotifera. The difference between the two optimality criteria is attributed to long-branch attraction. The two analyses are congruent in terms of relationships within Acanthocephala. The three sampled classes are monophyletic, and the Archiacanthocephala is the sister taxon of a Palaeacanthocephala + Eoacanthocephala clade. The phylogenetic hypothesis is used to assess the evolution of host and habitat preferences. Acanthocephalan lineages have exhibited multiple radiations into terrestrial habitats and bird and mammal definitive hosts from ancestral aquatic habitats and fish definitive hosts, while exhibiting phylogenetic conservatism in the type of arthropod intermediate host utilized.

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

    Directory of Open Access Journals (Sweden)

    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.

  19. Zooplankton assemblage of Oyun Reservoir, Offa, Nigeria

    Directory of Open Access Journals (Sweden)

    Moshood K Mustapha

    2009-12-01

    Full Text Available The influence of physico-chemical properties of Oyun Reservoir, Offa, Nigeria (a shallow tropical African reservoir on its zooplankton composition and abundance were investigated at three stations for two years between January 2002 and December 2003. Diversity is not high: only three groups of zooplankton were found: Rotifera with eight genera; and Cladocera and Copepoda with three genera each. Rotifera dominated numerically (71.02%, followed by Cladocera (16.45% and Copepoda (12.53%. The zooplankton was more prevalent during the rainy season, and there were variations in the composition and abundance along the reservoir continuum. Factors such as temperature, nutrients, food availability, shape and hydrodynamics of the reservoir, as well as reproductive strategies of the organisms, strongly influence the generic composition and population density of zooplankton. Prevention of ecological deterioration of the water body would greatly should result in a more productive water body, rich in zooplankton and with better fisheries. Rev. Biol. Trop. 57 (4: 1027-1047. Epub 2009 December 01.La influencia de las propiedades fisicoquímicas del Reservorio Oyun, Offa, Nigeria (un embalse tropical somero sobre la composición y abundancia del zooplancton fue investigada en tres estaciones entre enero de 2002 y diciembre de 2003. La diversidad no resultó muy alta con tres grupos de zooplancton: Rotifera con ocho géneros, y Cladocera y Copepoda con tres géneros cada uno. Rotifera dominó (71.02%, seguido de Cladocera (16.45% y Copepoda (12.53%. El zooplancton fue más común durante la temporada de lluvias, y hubo variaciones en su composición y abundancia a lo largo del embalse. Factores tales como la temperatura, los nutrientes, la disponibilidad de alimentos, la forma y la hidrodinámica del embalse, así como las estrategias reproductivas de los organismos, influyen fuertemente en la composición genérica y la densidad poblacional del zooplancton. La

  20. New insights on the musculature of filospermoid Gnathostomulida

    DEFF Research Database (Denmark)

    Gąsiorowski, Ludwik; Bekkouche, Nicolas Tarik; Sørensen, Martin Vinther

    2017-01-01

    variation: H. simplex possesses a simple grid of thick longitudinal and thin circular muscles, whereas H. filum shows a very sparse body wall musculature devoid of circular fibers, a pattern similar to another interstitial worm, the enigmatic annelid Lobatocerebrum. The flexibility gained hereby may....... In addition to known pharyngeal muscles we found new apophyseal abductors not uncovered in bursovaginoid gnathostomulids, but which resemble certain muscles of the sister group (Micrognathozoa + Rotifera) and may present an autapomorphy of Gnathifera. The body wall musculature exhibits greater interspecific...

  1. 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.

  2. Zooplankton community of Keibul Lamjao National Park (KLNP) Manipur, India in relation to the physico-chemical variables of the water

    Science.gov (United States)

    Sharma, Aribam Satishchandra; Gupta, Susmita; Singh, N. Rajmuhon

    2017-05-01

    Keibul Lamjao National Park (KLNP), a floating park in Loktak Lake, Manipur (India) was studied from Winter (WIN) to Post Monsoon (POM) for its zooplankton composition and some selected water parameters. The resultant data were subjected to multivariate techniques-Principal Component Analysis (PCA) and Canonical Correspondence Analysis (CCA). Analyses of water parameters with PCA revealed that the first PC axis (PC1) accounts for maximum variance in the seasonal data, explaining a variability of 91%. The PCA revealed that the seasonal variability in water parameters was due to the wet and dry cycle of seasons and the stations were distinguished on the basis of transparency and turbidity. Zooplankton abundance was dominated by copepods followed by cladocerans. Temporally, abundance of copepods reached a maximum during Post-monsoon (POM) (3 880 ind./L). Spatially, S6 was found to be most abundant of the other stations in zooplankton. Copepodites and nauplii larvae were the major components of zooplankton. The Rotifera were the least abundant among the three zooplankton groups. Brachionus formed the major component of Rotifera zooplankton at all the stations during the study period. In the Cladocera, Macrothrix was present during all the four seasons, while Pleuroxus, Oxyurella, Kurzia and, Diaphanosoma were rare. The CCA shows that maximal temporal variability in zooplankton abundance was explained by temperature and rainfall. ANOVA revealed no significant diff erence in mean zooplankton abundance among the seasons, but there was a statistically significant diff erence among the sites.

  3. Eukaryotic opportunists dominate the deep-subsurface biosphere in South Africa.

    Science.gov (United States)

    Borgonie, G; Linage-Alvarez, B; Ojo, A O; Mundle, S O C; Freese, L B; Van Rooyen, C; Kuloyo, O; Albertyn, J; Pohl, C; Cason, E D; Vermeulen, J; Pienaar, C; Litthauer, D; Van Niekerk, H; Van Eeden, J; Sherwood Lollar, B; Onstott, T C; Van Heerden, E

    2015-11-24

    Following the discovery of the first Eukarya in the deep subsurface, intense interest has developed to understand the diversity of eukaryotes living in these extreme environments. We identified that Platyhelminthes, Rotifera, Annelida and Arthropoda are thriving at 1.4 km depths in palaeometeoric fissure water up to 12,300 yr old in South African mines. Protozoa and Fungi have also been identified; however, they are present in low numbers. Characterization of the different species reveals that many are opportunistic organisms with an origin due to recharge from surface waters rather than soil leaching. This is the first known study to demonstrate the in situ distribution of biofilms on fissure rock faces using video documentation. Calculations suggest that food, not dissolved oxygen is the limiting factor for eukaryal population growth. The discovery of a group of Eukarya underground has important implications for the search for life on other planets in our solar system.

  4. Impact of changed trophic status on the zooplankton composition in six water bodies of Dharwad district, Karnataka state (South India).

    Science.gov (United States)

    Kudari, Vijaykumar A; Kanamadi, Ravishankar D

    2008-09-01

    The present paper cites results of zooplankton composition that carried out in the six water bodies of Dharwad district during September-November 2004 (post monsoon) and February-April 2005 (pre monsoon). Comparison of the obtained results with those of earlier investigations performed during 1978-1979 showed that changes have occurred in the interval. The total zooplankton composition is significantly changed in all the six water bodies. The lower value of Sorenson and Jaccard indices suggests that significant changes have occurred in the group rotifera and cladocera whereas the higher values for copepoda group suggests least changes. Concurrent occurrence of six Brachionus species in Unkal Lake, four species in Kelgeri, Nuggikeri and Navalur tanks indicate intensified eutrophication. If these habitats have to be preserved for their intended use there is a need for sustainable and holistic management.

  5. Documenting the fauna of a small temporary pond from Pune, Maharashtra, India

    Directory of Open Access Journals (Sweden)

    Mihir R. Kulkarni

    2015-05-01

    Full Text Available Most of the limnological studies in India have focussed on a few taxa of large, permanent water bodies, and pond ecosystems, and related temporary water bodies are neglected.  We present here a faunal inventory, with representative photographs, for a single, small temporary pond, reporting over 125 species of strictly aquatic fauna and 25 species of associated fauna, even though we did not identify some groups such as Protozoa, Diptera and nymphs of Odonata, etc.  The identified species belong to seven taxa of vertebrates and invertebrates together. Arthropoda and Rotifera were the most species rich groups, observed with 83 and 45 representatives, respectively. Coleoptera were the most numerous in terms of species number.  Such a small water body holds some endemics as well as otherwise very rare animals and so deserves better attention.  We also highlight the potential and importance of such habitats for research and conservation.   

  6. Sublittoral meiobenthic assemblages from disturbed and non-disturbed sediments in the Balearics

    Directory of Open Access Journals (Sweden)

    S. Deudero

    2000-09-01

    Full Text Available Qualitative and quantitative differences in species composition of meiobenthic communities illustrate the differences among various taxonomic assemblages in the Balearic Islands (Western Mediterranean analysed by means of multivariate analysis. Average densities ranged between 1000 and 4000 ind?10cm-2, and are in the same range as previously reported from other shallow Mediterranean areas. The dominant meiofaunal taxa were Nematoda (range 40 to 75%, Turbellaria (5-47% and Copepoda (2-14%, while other meiofaunal groups (Tardigrada and Rotifera were only represented by approximately 5% of the total abundance. The dominant nematode families were Desmodoridae, Chromadoridae and Xyalidae. The meiofaunal communities showed little variation among locations. Moreover, small-scale heterogeneity does not seem to affect nematode distribution as shown by the high similarity between replicates in the multivariate analysis.

  7. Sensitivity of plankton indices to lake trophic conditions.

    Science.gov (United States)

    Ochocka, A; Pasztaleniec, A

    2016-11-01

    Herein, we report the response of indices based on phytoplankton and zooplankton and their combination to different nutrient concentrations in lakes. The study was carried out in ten lakes in northeastern Poland. Integrated samples were collected from the epilimnion during the summer of 2012-2013. Secchi disk visibility (SD), total phosphorus (TP), total nitrogen (TN), and chlorophyll a were used as proxies for eutrophication. We calculated 16 plankton indices: two phytoplankton indices, six crustacean indices, five rotiferan indices, two zooplankton diversity indices, and one combined phytoplankton and zooplankton index. Among them, nine indices with the strongest correlations with TP were selected: percentage share of Crustacean species indicative of high trophy in the indicative group's numbers (IHT CRU ), percentage share of Rotifera species indicative of high trophy in the indicative group's numbers IHT ROT , Crustacean ratio of biomass to numbers B/N CRU , phytoplankton trophic index (TI TP+TN ), Margalef's index, percentage share of cyclopoid biomass in total biomass of Crustacea (CB), Rotifera numbers (N ROT ), biomass of Cyclopoida (B CY ), and ratio of the cyclopoid biomass to the biomass of Cladocera (CY/CL). The sensitivity of the normalized values of these indices to proxies of eutrophication was tested. IHT CRU , IHT ROT , and B/N CRU were the most sensitive and gave the strongest responses at lower TP concentrations (trophic index, TI TP+TN , together with the zooplankton-based Margalef's index and CB were very sensitive in both low (60 μg/L) TP conditions. On the other hand, N ROT , B CY , and CY/CL were slightly sensitive at low TP concentrations while their reaction was notable at high TP concentrations. A similar pattern of response was observed for TN concentration and SD visibility.

  8. Efeito das variáveis abióticas e do fitoplâncton sobre a comunidade zooplanctônica em um reservatório do Nordeste brasileiro Abiotic variables and phytoplankton effects on zooplanktonic community from a reservoir in northeast Brazil

    Directory of Open Access Journals (Sweden)

    Ênio W. Dantas

    2009-06-01

    Full Text Available O zooplâncton do reservatório de Mundaú, Pernambuco, nordeste do Brasil foi estudado quanto a variabilidade temporal (entre os horários e períodos seco chuvoso e espacial (nas regiões pelágica e litorânea em diferentes profundidades correlacionando-as com as variáveis ambientais e com o fitoplâncton. Vinte e três táxons infragenéricos e cinco subgenéricos de zooplâncton foram encontrados. De forma geral, Rotifera foi o grupo dominante em todo o estudo. O fitoplâncton foi dominado pelas cianobactérias. No período seco, as variáveis físicas certamente controlaram o desenvolvimento do zooplâncton, favorecendo o estabelecimento de elevadas densidades algais. No período chuvoso, a correlação do zooplâncton com os níveis de nutrientes do sistema na região pelágica provavelmente conduziu a uma competição de recursos entre o fitoplâncton e o zooplâncton, controlando as densidades algais.Zooplankton from Mundaú reservoir, State of Pernambuco, northeast Brazil was studied concerning temporal (hours and seasonal period and spatial (pelagic and coastal regions in different depths variabilities, correlating them to the environmental variables and the phytoplankton. Twenty-three infrageneric and five subgeneric zooplankton taxa were observed. On the whole, Rotifera was the dominant group during this study, especially influenced by the oxygen concentrations. Phytoplankton was dominated by Cyanobacteria. On the dry period, physical variables certainly controlled the zooplankton's development, allowing elevated algal densities. On the rainy period, zooplankton correlation with the system's nutrients levels on pelagic region probably conduced to a resources competition between phytoplankton and zooplankton, controlling algal densities.

  9. Utilization of macrophyte biofilter in effluent from aquaculture: I. Floating plant Utilização de biofiltros de macrófitas em efluentes de aqüicultura: I. Planta flutuante

    Directory of Open Access Journals (Sweden)

    L. H. SIPAÚBA-TAVARES

    2002-11-01

    Full Text Available The objective of this work was to manufacture a low-cost biofilter, made of floating macrophyte (Eichhornia crassipes. Limnological studies were conducted 7 days after the macrophytes were placed in the biofilter, and continued over a period of 30 consecutive days. During rainy and dry seasons, and high production period, samples were taken three times a week. The lowest levels of nitrogen compounds were observed in the July/August period, which corresponded to lower fish production and low supply rattion in the culture ponds. During the experimental period, pH values ranged from acid to alkaline and did not oscillate with higher average values during April/May. Alkalinity and bicarbonate dominance in the medium were directly affected by pH. With respect to associated micro-fauna, among phyto-plankton Chlorophyta was the dominant group and among zooplankton, Rotifera. It is recommended that during production peaks, the aquatic plants should be replaced by small buds every 10 days.O objetivo deste trabalho foi confeccionar um biofiltro de baixo custo constituído por macrófita flutuante (Eichhornia crassipes. Os estudos limnológicos foram realizados 7 dias depois de colocadas as macrófitas no biofiltro, durante um período de 30 dias consecutivos, com amostragens 3 vezes por semana nas épocas de chuva, seca e de alta produção de organismos cultivados. Quanto aos compostos nitrogenados, as menores concentrações foram observadas no período de jul./ago., correspondendo à época de baixa produção de peixes e baixa adição de alimento nos tanques e viveiros de cultivo. O pH manteve-se ligeiramente ácido a alcalino ao longo do período experimental, não apresentando oscilações com os maiores valores médios no período de abr./mai. Os valores de pH influenciaram diretamente a alcalinidade e a dominância de bicarbonato no meio. Quanto à microfauna associada, entre os fitoplanctônicos as Chlorophyta foram o grupo dominante e entre os

  10. Seasonal dynamics of the littoral zooplankton groups of the Uday River within the National Nature Park "Pyryatynsky"

    Directory of Open Access Journals (Sweden)

    Z. V. Burian

    2017-08-01

    Full Text Available The increase in anthropogenic impact on aquatic ecosystems causes significant alterations in the composition and structure of hydrobiont groups. These processes are characteristic of the hydrobiocenoses of the Uday River, the valley of which lies within the National Nature Park "Pyryatynsky", established in 2009 in the Pyryatyn district of Poltava region. Within this protected area it is convenient to carry out continuous monitoring of changes in anthropogenic load on shore ecosystems of the river. One of the most convenient monitoring groups is zooplankton, which is one of the essential components of the trophic networks of aquatic ecosystems and which is the feeding basis of planktonophagous and young fish. The object of this research was the major groups of zooplankton: rotifers (class Eurotatoria, cladocerans (class Branchiopoda, order Cladocera, different age stages of copepods (class Copepoda, ostracods (class Ostracoda. Zooplankton were collected in the daytime in spring (mid April, summer (end of July and autumn (late September 2016 within eight research stations. As a result of the conducted research, 69 species of zooplankton were registered within the littoral water area of the Uday River. Monogonont rotifers numbered 19 (27.5% species, bdelloid rotifers (subclass Bdelloidea, cladocerans – 33 (47.9% species, copepods – 17 (24.6%. According to the faunal spectrum in the zooplankton groups, representatives of the cladoceran complex predominated. This is due to the favourable conditions for the development of filtrators, of which a considerable part is cladocerans. Three species of rotifers were identified in Poltava region for the first time: Beauchampiella eudactylota (Gosse, 1886, Dipleuchlanis propatula (Gosse, 1886, Mytilina acanthophora (Hauer, 1938. During the spring, 33 species of zooplankton were collected: rotifers – 10 species, cladocerans – 14, copepods – 9 species. In summer 41 species were registered, including

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

    Directory of Open Access Journals (Sweden)

    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

  12. Conservation of estrogen receptor function in invertebrate reproduction.

    Science.gov (United States)

    Jones, Brande L; Walker, Chris; Azizi, Bahareh; Tolbert, Laren; Williams, Loren Dean; Snell, Terry W

    2017-03-04

    Rotifers are microscopic aquatic invertebrates that reproduce both sexually and asexually. Though rotifers are phylogenetically distant from humans, and have specialized reproductive physiology, this work identifies a surprising conservation in the control of reproduction between humans and rotifers through the estrogen receptor. Until recently, steroid signaling has been observed in only a few invertebrate taxa and its role in regulating invertebrate reproduction has not been clearly demonstrated. Insights into the evolution of sex signaling pathways can be gained by clarifying how receptors function in invertebrate reproduction. In this paper, we show that a ligand-activated estrogen-like receptor in rotifers binds human estradiol and regulates reproductive output in females. In other invertebrates characterized thus far, ER ligand binding domains have occluded ligand-binding sites and the ERs are not ligand activated. We have used a suite of computational, biochemical and biological techniques to determine that the rotifer ER binding site is not occluded and can bind human estradiol. Our results demonstrate that this mammalian hormone receptor plays a key role in reproduction of the ancient microinvertebrate Brachinous manjavacas. The presence and activity of the ER within the phylum Rotifera indicates that the ER structure and function is highly conserved throughout animal evolution.

  13. Abundance of plankton population densities in relation to bottom soil textural types in aquaculture ponds

    Directory of Open Access Journals (Sweden)

    F. Siddika

    2012-06-01

    Full Text Available Plankton is an important food item of fishes and indicator for the productivity of a water body. The present study was conducted to evaluate the effects of bottom soil textural conditions on abundance of plankton in aquaculture pond. The experiment was carried out using three treatments, i.e., ponds bottom with sandy loam (T1, with loam (T2 and with clay loam (T3. The ranges of water quality parameters analyzed were suitable for the growth of plankton during the experimental period. Similarly, chemical properties of soil were also within suitable ranges and every parameter showed higher ranges in T2. A total 20 genera of phytoplankton were recorded belonged to Chlorophyceae (7, Cyanophyceae (5, Bacillariophyceae (5, Euglenophyceae (2 and Dinophyceae (1. On the other hand, total 13 genera of zooplankton were recorded belonged to Crustacea (7 and Rotifera (6. The highest ranges of phytoplankton and zooplankton densities were found in T2 where low to medium-type bloom was observed during the study period. Consequently, the mean abundance of plankton (phytoplankton and zooplankton density was significantly highest in T2. The highest abundance of plankton in the T2 indicated that pond bottom with loamy soil is suitable for the growth and production of plankton in aquaculture ponds.

  14. Variaciones de abundancia y biomasa del zooplancton en un embalse tropical oligo-mesotrófico del norte de Venezuela

    Directory of Open Access Journals (Sweden)

    Sandra Merayo

    2010-06-01

    Full Text Available La abundancia del zooplancton en los embalses está determinada principalmente por la velocidad y el contenido del agua, pero se sabe relativamente poco sobre los embalses tropicales. Se estudió la distribución temporal y espacial de la abundancia y la biomasa del zooplancton en el eje longitudinal del embalse de Clavellinos, en el norte de Venezuela, entre octubre 2006 y septiembre 2007. El zooplancton fue recolectado en el estrato oxigenado con una red de plancton. Un total de 16 taxones fueron identificados: Copepoda, Cladocera, Rotifera, Ostracoda y Diptera. Thermocyclops decipiens (Copepoda, Cyclopoida dominó la comunidad, mientras que los rotíferos fueron los más diversos, con 10 especies. La abundancia del zooplancton varió de 31 a 101ind/l en E1, 36 a 84ind/l en E2, y, de 30 a 250ind/L en el E3. La biomasa varió de 97,4 a 1406.3μg/l en E1, 108,5 a 397.2μg/l en E2, y de 25,9 a 763.9μg/l en el E3. Esta comunidad de zooplancton pareciσ responder a las variaciones ambientales en el embalse, mαs que a las variaciones en la disponibilidad de recursos.

  15. Comparison of biofilm ecology supporting growth of individual Naegleria species in a drinking water distribution system.

    Science.gov (United States)

    Puzon, Geoffrey J; Wylie, Jason T; Walsh, Tom; Braun, Kalan; Morgan, Matthew J

    2017-04-01

    Free-living amoebae (FLA) are common components of microbial communities in drinking water distribution systems (DWDS). FLA are of clinical importance both as pathogens and as reservoirs for bacterial pathogens, so identifying the conditions promoting amoebae colonisation of DWDSs is an important public health concern for water utilities. We used high-throughput amplicon sequencing to compare eukaryotic and bacterial communities associated with DWDS biofilms supporting distinct FLA species (Naegleria fowleri, N. lovaniensis or Vermamoeba sp.) at sites with similar physical/chemical conditions. Eukaryote and bacterial communities were characteristics of different FLA species presence, and biofilms supporting Naegleria growth had higher bacterial richness and higher abundance of Proteobacteria, Bacteroidetes (bacteria), Nematoda and Rotifera (eukaryota). The eukaryotic community in the biofilms had the greatest difference in relation to the presence of N. fowleri, while the bacterial community identified individual bacterial families associated with the presence of different Naegleria species. Our results demonstrate that ecogenomics data provide a powerful tool for studying the microbial and meiobiotal content of biofilms, and, in these samples can effectively discriminate biofilm communities supporting pathogenic N. fowleri. The identification of microbial species associated with N. fowleri could further be used in the management and control of N. fowleri in DWDS. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. Independent origins of parasitism in Animalia.

    Science.gov (United States)

    Weinstein, Sara B; Kuris, Armand M

    2016-07-01

    Nearly half of all animals may have a parasitic lifestyle, yet the number of transitions to parasitism and their potential for species diversification remain unresolved. Based on a comprehensive survey of the animal kingdom, we find that parasitism has independently evolved at least 223 times in just 15 phyla, with the majority of identified independent parasitic groups occurring in the Arthropoda, at or below the level of Family. Metazoan parasitology is dominated by the study of helminthes; however, only 20% of independently derived parasite taxa belong to those groups, with numerous transitions also seen in Mollusca, Rotifera, Annelida and Cnidaria. Parasitism is almost entirely absent from deuterostomes, and although worm-like morphology and host associations are widespread across Animalia, the dual symbiotic and trophic interactions required for parasitism may constrain its evolution from antecedent consumer strategies such as generalist predators and filter feeders. In general, parasitic groups do not differ from their free-living relatives in their potential for speciation. However, the 10 largest parasitic clades contain 90% of described parasitic species, or perhaps 40% of all animal species. Hence, a substantial fraction of animal diversity on the Earth arose following these few transitions to a parasitic trophic strategy. © 2016 The Author(s).

  17. 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.

  18. Plankton Community Stability and Its Relationship with Phytoplankton Species Richness in Lake Nansihu, China

    Directory of Open Access Journals (Sweden)

    Wang Tian

    2016-10-01

    Full Text Available The relationship between biodiversity and ecosystem functioning is a central issue in ecology. The insurance hypothesis suggests that biodiversity could improve community productivity and reduce the temporal variability of main ecosystem processes. In the present study, we used a plankton community that was investigated from 2011 to 2014 in Lake Nansihu to test this hypothesis and explore the mechanisms involved. As a result, 138 phytoplankton and 76 zooplankton species were identified in the lake, and their biomasses showed apparent seasonal variations. The average temporal stability index of zooplankton taxa was significantly higher than that of phytoplankton. Complex relationships were observed between the species richness and temporal stability of different phytoplankton taxa: a unimodal relationship for both Cyanophyta and Bacillariophyta; a strong concave relationship for Euglenophyta; and no apparent relationship for both Chlorophyta and total phytoplankton. These relationships were primarily controlled by the portfolio effect; while the effects of overyielding and species asynchrony were relatively weak. Phytoplankton species richness had a significant positive influence on the temporal stability indices of protozoa, Rotifera and total zooplankton, while its influence on Cladocera and copepods was not significant. The dominant mechanisms were found to be ‘trophic overyielding’ and a weak ‘trophic portfolio effect’; however, ‘trophic species asynchrony’ played a minor role. These results demonstrated that the effects of diversity on community stability can be complex in natural ecosystems. In addition, the diversity of phytoplankton not only influenced its own temporal stability, but also affected the stability of zooplankton through trophic interactions.

  19. Feed of Siamese fighting fish, Betta splendens, (Regan, 1910 in open pond: live and formulated diets

    Directory of Open Access Journals (Sweden)

    L. H. Sipaúba-Tavares

    Full Text Available Abstract The growth rate and percent survival of Betta splendens when submitted to formulated diet and live food treatments are evaluated. The three different diets were used and designated as: formulated diet (basal diet; live food diet (plankton and mixed diet (formulated diet with plankton. The live food diet contained plankton belonging to an open pond. High mortality was reported with live food (plankton treatment whereas higher percent survival occurred with formulated diet. Highest specific growth rate, weight gain and final weight were reported in the mixed diet treatment and were significantly different (p<0.01 from those in formulated diet and live food treatments. The gut contents of B. splendens in mixed diet and live food treatments comprised, Rotifera and Bacillariophyceae species in high percentages or rather, over 78% of total organisms. Lecane sp. was the most ingested zooplankton species by B. splendens in both treatments (mixed diet and live food, with the phytoplankton species Asterionella sp. and Melosira sp. respectively in mixed diet and in live food, respectively. Results indicated that the formulated diet influenced the water parameters dissolved oxygen, total suspended solids, total dissolved solids and pH. The live food in the open pond was not enough to improve the growth rate and percent survival of B. splendens. The growth performance of B. splendens; had the best results with mixed diet which was capable of maintaining species’s survival (82% and development in artificial conditions, benefiting the culture management of ornamental fish.

  20. Abundance, food habits, and breeding season of exotic T ilapia zillii and native O reochromis niloticus L. fish species in Lake Zwai , Ethiopia

    Directory of Open Access Journals (Sweden)

    Padanillay C. Prabu

    2008-05-01

    Full Text Available Relative abundance, diet and breeding season overlap in the reproduction of exotic Tilapia zillii and native Oreochromis niloticus in Lake Zwai were studied from samples collected over 12 months. Younger fish of both species collected were also evaluated for food composition.Food items from stomachs of both species were collected and analysed using the frequency of occurrence method. In terms of number, T. zillii dominated O. niloticus at the sampling sites. In both species, macrophytes, detritus, blue green algae, diatoms, green algae, Ceratium, Euglena,and Phacus constituted foods of plant origin, whereas chironomid larvae, Copepoda, Cladocera,Rotifera, Nematoda, fish eggs, and fish scales constituted foods of animal origin. Foods of the latter type such as Ephemeroptera and mollusks were also noted in the diet of adult T. zillii.Despite the extensive overlap in food habits of the two species, however, the food items were found in the diet of the species with different average percentage frequencies of occurrence. The level of gonad maturation and gonadosomatic index (GSI values showed that in Lake Zwai breeding was year-round for both T. zillii and O. niloticus, with a peak during April-September and February-August respectively, indicating extended breeding season overlap in reproduction. The two species were always found together in the catches from the sampling sites, which indicated some niche overlap between them.

  1. Impact of environmental factors on maintaining water quality of Bakreswar reservoir, India

    Directory of Open Access Journals (Sweden)

    Moitreyee Banerjee

    2015-09-01

    Full Text Available Reservoirs and dams are engineered systems designed to serve purposes like supply of drinking water as well as other commercial and industrial use. A thorough assessment of water quality for these systems is thus necessary. The present study is carried out at Bakreswar reservoir, in Birbhum district, which was created by the dam, built on Bakreswar River. The major purpose of the reservoir is the supply of drinking water to the surrounding villages and Bakreswar Thermal Power Station. Water samples were collected fortnightly from three different stations of the reservoir. Physical and chemical factors like dissolved oxygen, atmospheric temperature, pH, conductivity, salinity, solar radiation, water temperature, alkalinity, hardness, chloride, productivity etc. were analysed using standard procedure. Abundance data is calculated for four major groups of zooplanktons (Cladocera, Copepoda, Ostracoda, and Rotifera with the software PAST 2.1. Multivariate statistical analysis like PCA, hierarchical cluster and CCA are performed in order to predict the temporal variation in the water quality factors using SPSS 20. Distinct seasonal variation was found for environmental factors and zooplankton groups. Bakreswar reservoir has good assemblage of zooplankton and distinct temporal variation of environmental factors and its association with zooplankton predicts water quality condition. These results could help in formulating proper strategies for advanced water quality management and conservation of reservoir ecosystem. Key elements for growth and sustenance of the system can then be evaluated and this knowledge can be further applied for management purposes.

  2. Molecular Phylogeny of the Acanthocephala (Class Palaeacanthocephala) with a Paraphyletic Assemblage of the Orders Polymorphida and Echinorhynchida

    Science.gov (United States)

    Verweyen, Lisa; Klimpel, Sven; Palm, Harry W.

    2011-01-01

    Acanthocephalans are attractive candidates as model organisms for studying the ecology and co-evolutionary history of parasitic life cycles in the marine ecosystem. Adding to earlier molecular analyses of this taxon, a total of 36 acanthocephalans belonging to the classes Archiacanthocephala (3 species), Eoacanthocephala (3 species), Palaeacanthocephala (29 species), Polyacanthocephala (1 species) and Rotifera as outgroup (3 species) were analyzed by using Bayesian Inference and Maximum Likelihood analyses of nuclear 18S rDNA sequence. This data set included three re-collected and six newly collected taxa, Bolbosoma vasculosum from Lepturacanthus savala, Filisoma rizalinum from Scatophagus argus, Rhadinorhynchus pristis from Gempylus serpens, R. lintoni from Selar crumenophthalmus, Serrasentis sagittifer from Johnius coitor, and Southwellina hispida from Epinephelus coioides, representing 5 new host and 3 new locality records. The resulting trees suggest a paraphyletic arrangement of the Echinorhynchida and Polymorphida inside the Palaeacanthocephala. This questions the placement of the genera Serrasentis and Gorgorhynchoides within the Echinorhynchida and not the Polymorphida, necessitating further insights into the systematic position of these taxa based on morphology. PMID:22163005

  3. Molecular phylogeny of the Acanthocephala (class Palaeacanthocephala with a paraphyletic assemblage of the orders Polymorphida and Echinorhynchida.

    Directory of Open Access Journals (Sweden)

    Lisa Verweyen

    Full Text Available Acanthocephalans are attractive candidates as model organisms for studying the ecology and co-evolutionary history of parasitic life cycles in the marine ecosystem. Adding to earlier molecular analyses of this taxon, a total of 36 acanthocephalans belonging to the classes Archiacanthocephala (3 species, Eoacanthocephala (3 species, Palaeacanthocephala (29 species, Polyacanthocephala (1 species and Rotifera as outgroup (3 species were analyzed by using Bayesian Inference and Maximum Likelihood analyses of nuclear 18S rDNA sequence. This data set included three re-collected and six newly collected taxa, Bolbosoma vasculosum from Lepturacanthus savala, Filisoma rizalinum from Scatophagus argus, Rhadinorhynchus pristis from Gempylus serpens, R. lintoni from Selar crumenophthalmus, Serrasentis sagittifer from Johnius coitor, and Southwellina hispida from Epinephelus coioides, representing 5 new host and 3 new locality records. The resulting trees suggest a paraphyletic arrangement of the Echinorhynchida and Polymorphida inside the Palaeacanthocephala. This questions the placement of the genera Serrasentis and Gorgorhynchoides within the Echinorhynchida and not the Polymorphida, necessitating further insights into the systematic position of these taxa based on morphology.

  4. Food of forage fishes in western Lake Erie, 1975-76

    Science.gov (United States)

    Muth, Kenneth M.; Busch, Wolf-Dieter N.

    1989-01-01

    In western Lake Erie in the summer and fall of 1975–1976, food eaten by seven forage fishes—emerald shiner (Notropis atherinoides), spottail shiner (Notropis hudsonius), trout-perch (Percopsis omiscomaycus), andyoung-of-the-year (YOY) of alewife (Alosa pseudoharengus), gizzard shad (Dorosoma cepedianum), white bass (Morone chrysops), and freshwater drum (Aplodi-notus grunniens)—was divided among six major taxa: Cladocera, Copepoda, Diptera, Ostracoda, Amphipoda, and Algae. In addition, fish were eaten by YOY white bass, and Rotifera were consumed by YOY gizzard shad. Interspecies diet overlap indices, calculated to compare the food of the different species and to evaluate diet similarities, were usually highest for YOY white bass and YOY freshwater drum when compared with the other species and usually lowest between emerald shiners and all other forage fishes. Understanding the feeding interactions among fishes that could influence production at the forage-food level of the food web could provide insight into how cascading trophic interactions influence the production of piscivorous predators.

  5. Tardigrades in Space Research - Past and Future

    Science.gov (United States)

    Weronika, Erdmann; Łukasz, Kaczmarek

    2017-12-01

    To survive exposure to space conditions, organisms should have certain characteristics including a high tolerance for freezing, radiation and desiccation. The organisms with the best chance for survival under such conditions are extremophiles, like some species of Bacteria and Archea, Rotifera, several species of Nematoda, some of the arthropods and Tardigrada (water bears). There is no denying that tardigrades are one of the toughest animals on our planet and are the most unique in the extremophiles group. Tardigrada are very small animals (50 to 2,100 μm in length), and they inhabit great number of Earth environments. Ever since it was proven that tardigrades have high resistance to the different kinds of stress factors associated with cosmic journeys, combined with their relatively complex structure and their relative ease of observation, they have become a perfect model organism for space research. This taxon is now the focus of astrobiologists from around the world. Therefore, this paper presents a short review of the space research performed on tardigrades as well as some considerations for further studies.

  6. Applicability of cryoconite consortia of microorganisms and glacier-dwelling animals in astrobiological studies

    Directory of Open Access Journals (Sweden)

    Zawierucha Krzysztof

    2017-06-01

    Full Text Available For several years it has been of interest to astrobiologists to focus on Earth’s glaciers as a habitat that can be similar to glaciers on other moons and planets. Microorganisms on glaciers form consortia – cryoconite granules (cryoconites. They are granular/spherical mineral particles connected with archaea, cyanobacteria, heterotrophic bacteria, algae, fungi, and micro animals (mainly Tardigrada and Rotifera. Cryophilic organisms inhabiting glaciers have been studied in different aspects: from taxonomy, ecology and biogeography, to searching of biotechnological potentials and physiological strategies to survive in extreme glacial habitats. However, they have never been used in astrobiological experiments. The main aim of this paper is brief review of literature and supporting assumptions that cryoconite granules and microinvertebrates on glaciers, are promising models in astrobiology for looking for analogies and survival strategies in terms of icy planets and moons. So far, astrobiological research have been conducted on single strains of prokaryotes or microinvertebrates but never on a consortium of them. Due to the hypothetical similarity of glaciers on the Earth to those on other planets these cryoconites consortia of microorganisms and glacier microinvertebrates may be applied in astrobiological experiments instead of the limno-terrestrial ones used currently. Those consortia and animals have qualities to use them in such studies and they may be the key to understanding how organisms are able to survive, reproduce and remain active at low temperatures.

  7. Tardigrades in Space Research - Past and Future.

    Science.gov (United States)

    Weronika, Erdmann; Łukasz, Kaczmarek

    2017-12-01

    To survive exposure to space conditions, organisms should have certain characteristics including a high tolerance for freezing, radiation and desiccation. The organisms with the best chance for survival under such conditions are extremophiles, like some species of Bacteria and Archea, Rotifera, several species of Nematoda, some of the arthropods and Tardigrada (water bears). There is no denying that tardigrades are one of the toughest animals on our planet and are the most unique in the extremophiles group. Tardigrada are very small animals (50 to 2,100 μm in length), and they inhabit great number of Earth environments. Ever since it was proven that tardigrades have high resistance to the different kinds of stress factors associated with cosmic journeys, combined with their relatively complex structure and their relative ease of observation, they have become a perfect model organism for space research. This taxon is now the focus of astrobiologists from around the world. Therefore, this paper presents a short review of the space research performed on tardigrades as well as some considerations for further studies.

  8. Diel vertical migration and distribution of zooplankton in a tropical Brazilian reservoirlian

    Directory of Open Access Journals (Sweden)

    Ana M. A. da Silva

    2009-08-01

    amostradas em quatro profundidades (Sub-superfície, 50% Io, 1% Io e Fundo em uma estação de amostragem com cinco metros de profundidade, em intervalos de quatro horas, ao longo de 24 horas. Duas espécies de Cladocera (Moina minuta e Diaphanosoma spinulosum e uma espécie de Copepoda (Notodiaptomus cearensis apresentaram padrões relativamente semelhantes de migração noturna, permanecendo no fundo durante o dia e se deslocando próximo à superfície no fim da tarde e ao longo da noite. Brachionus falcatus e Hexarthra mira (Rotifera não apresentaram padrões migratórios e as suas distribuições verticais foram relativamente homogêneas. As variáveis ambientais e as distribuições das espécies correlacionaram-se fracamente, sugerindo que outros mecanismos podem ser responsáveis por induzir a migração vertical.

  9. Variaciones de abundancia y biomasa del zooplancton en un embalse tropical oligo-mesotrófico del norte de Venezuela

    Directory of Open Access Journals (Sweden)

    Sandra Merayo

    2010-06-01

    Full Text Available La abundancia del zooplancton en los embalses está determinada principalmente por la velocidad y el contenido del agua, pero se sabe relativamente poco sobre los embalses tropicales. Se estudió la distribución temporal y espacial de la abundancia y la biomasa del zooplancton en el eje longitudinal del embalse de Clavellinos, en el norte de Venezuela, entre octubre 2006 y septiembre 2007. El zooplancton fue recolectado en el estrato oxigenado con una red de plancton. Un total de 16 taxones fueron identificados: Copepoda, Cladocera, Rotifera, Ostracoda y Diptera. Thermocyclops decipiens (Copepoda, Cyclopoida dominó la comunidad, mientras que los rotíferos fueron los más diversos, con 10 especies. La abundancia del zooplancton varió de 31 a 101ind/l en E1, 36 a 84ind/l en E2, y, de 30 a 250ind/L en el E3. La biomasa varió de 97,4 a 1406.3μg/l en E1, 108,5 a 397.2μg/l en E2, y de 25,9 a 763.9μg/l en el E3. Esta comunidad de zooplancton pareciσ responder a las variaciones ambientales en el embalse, mαs que a las variaciones en la disponibilidad de recursos.Variations of zooplankton abundance and biomass in a tropical oligo-mesotrophic reservoir in Northern Venezuela. Zooplankton abundance in reservoirs is mainly determined by the speed and content of the water, but relatively little is known regarding tropical reservoirs. We studied the seasonal and spatial distribution of zooplankton abundance and biomass along the longitudinal axis of Clavellinos reservoir, northern Venezuela, from October 2006 to September 2007. Zooplankton was collected from the oxygenated layer using a plankton net. A total of 16 taxa were identified: Copepoda, Cladocera, Rotifera, Ostracoda and Diptera. Thermocyclops decipiens (Copepoda, Cyclopoida dominated the community, while rotifers were the most diverse, with 10 species. Zooplankton abundance varied from 31 to 101ind/L in E1, 36 to 84ind/L in E2, and, from 30 to 250ind/L in E3. Biomass varied from 97.4 to

  10. Vertical distribution of zooplankton in the water column of Lago Amapá, Rio Branco, Acre, Brazil

    Directory of Open Access Journals (Sweden)

    Erlei Cassiano Keppeler

    2004-06-01

    Full Text Available The aim of investigation was to study the model of vertical distribution in Lago Amapá, taking into consideration the seasonality of its zooplanktonic composition. Lago Amapá (10º2'36"S and 67º50'24"W is located in the floodplain of the Rio Acre. Samplings were conducted at three different depths of the water column, to study the vertical distribution of zooplankton populations and determine some physico-chemical and biological parameters of Lago Amapá. Weekly samples were taken with a Van Dorn sampler. The species showed greater concentrations at the by means of water column. Thirty-eight zooplankton species were found in the samples represented by Rotifera (30, Cladocera (5 and Cyclopoida (3. The temperature of the water column showed a tendency toward relatively high values (about 30ºC with little variation, consequently resulting in low viscosity. Based of Jaccard's index, it was seen that during the low-water phase, S1 and S3 of the three sampling stations studied, had greater similarity (Cj = 0.7058 in the middle of the water column. Lago Amapá showed characteristics in line with the intermediate disturbance hypothesis model, favoring colonization by opportunistic species such as rotifers.O objetivo desta investigação foi observar a distribuição vertical da comunidade do zooplâncton no Lago Amapá (10º2'36"S e 67º50'24"W, localizado na planície de inundação do Rio Acre. Amostragens foram conduzidas em três diferentes profundidades da coluna da água, considerando aspectos sazonais do zooplâncton, parâmetros físicos, químicos e biológicos. Coletas foram realizadas semanalmente com Garrafa de Van Dorn. As espécies apresentaram maiores concentrações no meio da coluna da água. Foram encontradas 38 espécies, assim distribuídas: Rotifera (30, Cladocera (5 e Cyclopoida (3. A temperatura da coluna da água em geral apresentou-se alta, em torno de 30ºC, com pequena variação, resultando em baixa viscosidade. O

  11. Hirfanlı Baraj Gölü (Kırşehir, Türkiye'nde yaşayan kadife balığı (Tinca tinca (Linnaeus, 1758'nın beslenme özellikleri.

    Directory of Open Access Journals (Sweden)

    Özlem Ablak Gürbüz

    2015-12-01

    Full Text Available Hirfanlı Baraj Gölü’nden avlanan ve 0-VI yaş grupları arasında dağılım gösteren 249 adet Kadife balığı (Tinca tinca’nın beslenme biyolojisi incelenmiştir. Tinca tinca’nın besin tercihinin tespit edilebilmesi için Geometrik Önem İndeksi (GII metodu kullanılmıştır. Ayrıca balığın besin tercihindeki aylık, mevsimlik ve yıllık değişim de incelenmiştir. Balıkların sindirim kanalında zooplanktonik (Copepoda, Rotifera, Cladocera, Ostracoda, Ephippium ve bentik (Chironomus, Oligochaeta, Gastropoda, Corethra, Gammarus organizmalar ile bunlara ait ekstremite parçaları, fitoplanktonik organizmalar (Bacillariophyta, Cyanophyta, Chlorophyta, Pyrrophyta, Euglenophyta, çamur, detritus ve balık yumurtası tespit edilmiştir. Bu çalışmada alglerin en çok tercih edilen besin tipi olduğu, bunu zooplanktonik ve bentik organizmaların takip ettiği belirlenmiştir. Tinca tinca’nın sindirim kanalında 44’ü bitkisel 16’sı hayvansal olmak üzere toplam 60 besin çeşidi saptanmıştır. Beslenmenin en fazla olduğu mevsimler sırasıyla yaz, sonbahar, kış ve ilkbahar olarak saptanmıştır. Sindirim kanalı dolu birey sayısı yaz ve sonbahar aylarında daha fazla bulunmuştur

  12. Evaluation of some water characteristics of the blue nile in Khartoum state as indicators of river nile pollution

    International Nuclear Information System (INIS)

    Khilla, E. E. A.

    2004-05-01

    This study investigated some physical, chemical and biological characteristics of the Blue nile river in Khartoum state. Four sites were chosen and studied namely. River transport corporation. Burri and Bahri power stations and Manshiya bridge (under construction) between may and july 2003. Four classes of phytoplankton were encountered: chlorophyceae, chrysophyceae, bacillariophyceae; with the last two classes being the most dominant.The zooplankton was represented by the genera copepoda- the dominant one- cladocera and rotifera. River transport corporation site showed higher total coliform counts during may and june, while all four stations showed the highest count (>100 MPN per 100 ml) in july. Values for total coliform and fecal bacteria were higher than previous studies which could be an indication that the blue nile river is polluted with both total coliform and fecal coliform bacteria. Pollution indicators were also manifested in relatively higher values of BOD, COD, and NO 3N , NO 2N .This could be attributed to anthropogenic activities such as bickerers, agricultural runoff, human and animal waste. Some of the changes were attributed to the natural hydrological regime of the Blue nile river such as increase of temperature, transparency and pH, at low flood period and the increase in TDS and conductivity; decline in transparency besides the disappearance of plankton with the onset of floodwater. The site of Manshiya bridge exhibited lowest transparency value due to dredging activities.The investigation within the Manshiya bridge site (under construction ), albeit done in a preliminary way. is the first of its kind in Sudan. The data indicate that the Blue nile river within Khartoum state has undergone physical, chemical and biological changes.The magnitude, causes and trends are yet to be elucidated.The study calls for an urgent, proper and long-term investigation of the Blue nile as well as the major rivers in Sudan.(Author)

  13. Environmental changes and zooplankton temporal and spatial variation in a disturbed Brazilian coastal lagoon.

    Science.gov (United States)

    Branco, C W C; Kozlowsky-Suzuki, B; Esteves, F A

    2007-05-01

    The Imboassica lagoon, located in the Municipality of Macaé (RJ), is separated from the sea by a sand bar, and its surroundings are partially occupied by residential areas. This coastal lagoon has undergone environmental degradation due to sewage input and artificial sand bar openings. The temporal and spatial variation of environmental variables and zooplankton were studied monthly for four years. There were five artificial openings of the sand bar during the period of study, mostly in the rainy season. Besides osmotic changes, these events caused the drainage of the water of the lagoon into the sea, loss of total organic nitrogen, and an increase of total phosphorus. The zooplankton community of Imboassica lagoon included freshwater and marine taxa, holoplanktonic, meroplanktonic and nectobenthonic forms. Polychaeta, Bivalvia and Gastropoda larvae, and the taxa of Rotifera Hexarthra spp., Lecane bulla, Synchaeta bicornis, nauplii of Cyclopoida and Calanoida copepods were considered constant taxa. Distinct zooplankton assemblages were found during zooplankton spatial surveys in oligohaline and mesohaline conditions. The successful zooplankton populations were either favored by the disturbance of the sand bar opening, such as the veligers of the gastropod Heleobia australis, or capable of fast recovery after the closing of the sand bar, during the succession from a marine into an oligohaline environment, such as Hexarthra spp.. Such populations seemed well adapted to the stress conditions usually found in the lagoon due to osmotic changes, column mixing, nutrient input, and high fish predation pressure. Rare species in the community, such as Moina minuta, presented population increases all over the lagoon under oligohaline conditions.

  14. Environmental changes and zooplankton temporal and spatial variation in a disturbed brazilian coastal lagoon

    Directory of Open Access Journals (Sweden)

    CWC. Branco

    Full Text Available The Imboassica lagoon, located in the Municipality of Macaé (RJ, is separated from the sea by a sand bar, and its surroundings are partially occupied by residential areas. This coastal lagoon has undergone environmental degradation due to sewage input and artificial sand bar openings. The temporal and spatial variation of environmental variables and zooplankton were studied monthly for four years. There were five artificial openings of the sand bar during the period of study, mostly in the rainy season. Besides osmotic changes, these events caused the drainage of the water of the lagoon into the sea, loss of total organic nitrogen, and an increase of total phosphorus. The zooplankton community of Imboassica lagoon included freshwater and marine taxa, holoplanktonic, meroplanktonic and nectobenthonic forms. Polychaeta, Bivalvia and Gastropoda larvae, and the taxa of Rotifera Hexarthra spp., Lecane bulla, Synchaeta bicornis, nauplii of Cyclopoida and Calanoida copepods were considered constant taxa. Distinct zooplankton assemblages were found during zooplankton spatial surveys in oligohaline and mesohaline conditions. The successful zooplankton populations were either favored by the disturbance of the sand bar opening, such as the veligers of the gastropod Heleobia australis, or capable of fast recovery after the closing of the sand bar, during the succession from a marine into an oligohaline environment, such as Hexarthra spp.. Such populations seemed well adapted to the stress conditions usually found in the lagoon due to osmotic changes, column mixing, nutrient input, and high fish predation pressure. Rare species in the community, such as Moina minuta, presented population increases all over the lagoon under oligohaline conditions.

  15. Mechanisms underlying recovery of zooplankton in Lake Orta after liming

    Directory of Open Access Journals (Sweden)

    Roberta Piscia

    2016-04-01

    Full Text Available The goal of this study was to improve the understanding of the large-scale mechanisms underlying the recovery of the zooplankton of Lake Orta from historical contamination, following reduced input of ammonia and metals and the subsequent 1989/90 liming intervention. The industrial pollution had been severe and long-lasting (1929-1990. Zooplankton biodiversity has improved, but most of the new taxa appearing in our counts are rotifers, while many calanoids and the large cladoceran predators (Bythotrephes and Leptodora that are common in the nearby Lake Maggiore, were still absent from Lake Orta 17 years after liming. To aid understanding of the large-scale mechanisms controlling changes in annual richness, we assessed the annual persistence (P of Crustacea and Rotifera taxa as an estimator of whether propagules that survived introduction, as result of the natural recolonization process, also thrived. We found that the rate of introduction of zooplankton colonists and their persistence in the water column of Lake Orta changed from 1971 to 2007. New rotifer taxa appeared in the lake after the mid-1980s, when discharge of toxic substances decreased, but their annual persistence was low (P<0.5 until the turn of the century. The numerical values of rotifer and crustacean persistence in Lake Orta were unexpectedly high in 2001 and 2007 (0.55 and 0.72 for rotifers, 0.85 and 0.86 for crustacean, respectively, much higher than in limed lakes in Sudbury, Canada, and in adjacent Lake Maggiore. We hypothesize this could be related to the lack of Cladoceran predators and zooplanktivorous fish in the pelagic waters of Lake Orta.

  16. Composición y abundancia del zooplancton en la laguna El Morro, Isla de Margarita, Venezuela

    Directory of Open Access Journals (Sweden)

    William Villalba

    2017-12-01

    Full Text Available Se analizó la composición y abundancia del zooplancton de la laguna El Morro en la isla de Margarita, Venezuela, durante el periodo de surgencia (marzo-mayo 2011 y de relajación (junio-agosto 2011. Las muestras fueron recolectadas en 6 estaciones de las diferentes zonas de la laguna. Se realizaron calados con una red de plancton de 333 µm durante 10 minutos. Se midió in situ la temperatura, salinidad y oxígeno disuelto, además de nutrientes. Se registraron valores medios de temperatura de 29.7 ºC, salinidad de 36 ups, oxígeno disuelto de 5.9 mg.L-1. La concentración de nutrientes fue baja (medias de 0.12; 0.04; 0.03 mg.L-1 para nitrato, nitrito y fosfato, respectivamente. Se detectaron diferencias significativas temporales con mayores registros en la temporada de relajación, mientras que espacialmente no mostró diferencias, a pesar que en las estaciones internas (Est. 4,5,6 se obtuvo mayor abundancia. Se identificaron quince grupos zooplanctónicos, determinándose nueve especies del grupo Copepoda, dos de Cladocera, una de Decapoda, Tunicada y Rotifera y diferentes formas larvarias de distintos taxa. Las larvas de crustáceos presentaron la abundancia media y relativa más alta (47738 ind.m-3 y 46.83%, respectivamente, seguido del copépodo Oithona nana (31740 ind.m-3 y 25.94%, respectivamente y Paracalanus quasimodo (12958 ind.m-3 y 8.47%, respectivamente. Esta laguna involucra la estacionalidad surgencia-relajación como un efecto importante en la distribución y abundancia del zooplancton.

  17. Epiphytic invertebrate patterns in coastal lakes along a gradient of salinity and water exchange with the sea

    Science.gov (United States)

    Obolewski, Krystian; Bąkowska, Martyna

    2017-10-01

    The species composition and abundance of epiphytic fauna inhabiting common reed (Phragmites australis (Cav.) Trin. ex Steud.) was performed in five coastal lakes in Słowiński National Park (southern Baltic coast in northern Poland). The lakes represent a salinity gradient (from freshwater to β-oligohaline waters) and four types of coastal lakes: (1) lagoon, L (Lake Łebsko, seawater enters it permanently); (2) coastal lake with periodically brackish water, CLB (Lake Gardno); (3) freshwater costal lake, CLF (Lake Smołdzińskie); and (4) coastal dune lakes, CLD (Dołgie Wielkie and Dołgie Małe). Using statistical ordination techniques, we found that the structure of epiphytic fauna (microinvertebrates and macroinvertebrates) is determined primarily by hydrological connectivity (water exchange) with the sea. Canonical Correspondence Analysis, coupled with variance partitioning, showed that hydrological connectivity accounted for 24% of the variation in the invertebrate community, followed by physico-chemical (19%) and trophic (8%) factors. Our results indicate that the assemblages of Ciliata-libera and Cnidaria are characteristic for L (β-oligohaline), Rotifera, Suctoria, Chaetogaster sp., Gastropoda and Trichoptera are characteristic for CLB (limnetic/β-oligohaline), but no taxonomic groups are characteristic for CLF and CLD (both limnetic). The index of multivariate dispersion showed a decreasing trend with the increasing lake isolation from the open sea, except for CLD. However, in terms of the structure of epiphytic fauna, Multi-Response Permutation Procedures showed that CLD significantly differed only from CLB. Our results suggest that the identified characteristic taxonomic groups of plant-associated macroinvertebrates have a high potential to be used as bioindicators of salinity and water exchange with the sea, due to their sensitivity to environmental stress.

  18. Trophic ecology of the freshwater prawn, Pseudopalaemon bouvieri (Decapoda: Palaemonidae in Northeastern Argentina: with remarks on population structure

    Directory of Open Access Journals (Sweden)

    Romina Patricia Carnevali

    2012-03-01

    Full Text Available Freshwater decapod crustaceans are important components of food webs in these environments, but little is known about the diet of species that live in tropical waters. We studied the feeding ecology of the prawn Pseudopalaemon bouvieri and its population structure in two different areas with six lagoons, with a different composition and abundance of aquatic macrophytes. At each site of macrophytes banks, 18 prawns sample was collected with a hand net (1mm mesh size from 1m². In the laboratory, prawns cephalothorax length was measured, sex determined, and a total of 208 stomachs were examined for food items. Our results showed that the population abundance varied between 10 ind/m² and 1 411 ind/m². The cephalothorax length ranged between 6mm and 21mm, and the male:female ratio varied between 0.3 and 1.0, with a higher proportion of ovigerous females (21% in area one than area two. P. bouvieri is omnivorous, and its diet was principally based on algae, plant remains, Protozoa, Rotifera, Oligochaeta, Crustacea, Insecta, detritus and other items. The analysis of the stomach content did not reveal any significant difference in the diet between juveniles and adults, and males and females of both areas consumed a similar diet (Kruskal-Wallis test p=0.8273. We concluded that the dietary items consumed by prawns and the niche breadth were similar between the two areas, although the proportion of items consumed varied between lagoons of both areas. The density of P. bouvieri was different between areas, but the size of cephalothorax (CL was similar.

  19. Feeding activity and influence of intraspecific competition on zooplankton communities by jundiá (Rhamdia quelen Quoy and Gaimard, 1824 in laboratory

    Directory of Open Access Journals (Sweden)

    L. Brandão-Gonçalves

    Full Text Available Experiments were designed to determine if the juvenile forms of jundia (Rhamdia quelen exhibit selectivity feeding on zooplanktonic organisms and the influence of intraspecific competition on the diet. The fish were maintained in 5000-L containers, and after seven days from birth, they were acclimated in experimental units with different densities and supplied with water containing plankton (natural, where they remained for 24 h in the environment with food. In the first seven days at densities of 5 and 10 fish.L–1, the fish selected the Rotifera more intensely, and at densities of 20 and 40 fish.L–1, the Cladocera were more selected. At 14 days of age, the Cladocera were the most selected for all densities of fish. At 21 days of age, the juvenile forms of jundia maintained a preference for Cladocera, and there was an increase in the capture of Copepoda at a density of 40 fish.L–1. At 28 days of age, the Cladocera were the most captured at densities of 5 to 20 fish.L–1, and the consumption of copepods increased at a density of 40 fish.L–1. The juvenile forms of Rhamdia quelen showed a high feeding preference for Cladocera at all the ages tested (7, 14, 21 and 28 days, but the density of fish per litre influenced the capture of the preferential food. This study showed that the juvenile forms of jundia had a more rapid response to the presence of food at densities of more than 10 fish.L–1, and that at higher densities the fish decreased interactions of territorial defense and formed schools, which allowed the foraging of zooplanktonic organisms, larger in size, more agile and of greater energy gain, such as the Cladocera and copepods.

  20. Feeding activity and influence of intraspecific competition on zooplankton communities by jundiá (Rhamdia quelen Quoy and Gaimard, 1824) in laboratory.

    Science.gov (United States)

    Brandão-Gonçalves, L; Sebastien, N Y

    2013-11-01

    Experiments were designed to determine if the juvenile forms of jundia (Rhamdia quelen) exhibit selectivity feeding on zooplanktonic organisms and the influence of intraspecific competition on the diet. The fish were maintained in 5000-L containers, and after seven days from birth, they were acclimated in experimental units with different densities and supplied with water containing plankton (natural), where they remained for 24 h in the environment with food. In the first seven days at densities of 5 and 10 fish.L-1, the fish selected the Rotifera more intensely, and at densities of 20 and 40 fish.L-1, the Cladocera were more selected. At 14 days of age, the Cladocera were the most selected for all densities of fish. At 21 days of age, the juvenile forms of jundia maintained a preference for Cladocera, and there was an increase in the capture of Copepoda at a density of 40 fish.L-1. At 28 days of age, the Cladocera were the most captured at densities of 5 to 20 fish.L-1, and the consumption of copepods increased at a density of 40 fish.L-1. The juvenile forms of Rhamdia quelen showed a high feeding preference for Cladocera at all the ages tested (7, 14, 21 and 28 days), but the density of fish per litre influenced the capture of the preferential food. This study showed that the juvenile forms of jundia had a more rapid response to the presence of food at densities of more than 10 fish.L-1, and that at higher densities the fish decreased interactions of territorial defense and formed schools, which allowed the foraging of zooplanktonic organisms, larger in size, more agile and of greater energy gain, such as the Cladocera and copepods.

  1. Global isolation by distance despite strong regional phylogeography in a small metazoan

    Directory of Open Access Journals (Sweden)

    Mills Scott

    2007-11-01

    Full Text Available Abstract Background Small vagile eukaryotic organisms, which comprise a large proportion of the Earth's biodiversity, have traditionally been thought to lack the extent of population structuring and geographic speciation observed in larger taxa. Here we investigate the patterns of genetic diversity, amongst populations of the salt lake microscopic metazoan Brachionus plicatilis s. s. (sensu stricto (Rotifera: Monogononta on a global scale. We examine the phylogenetic relationships of geographic isolates from four continents using a 603 bp fragment of the mitochondrial COI gene to investigate patterns of phylogeographic subdivision in this species. In addition we investigate the relationship between genetic and geographic distances on a global scale to try and reconcile the paradox between the high vagility of this species and the previously reported patterns of restricted gene flow, even over local spatial scales. Results Analysis of global sequence diversity of B. plicatilis s. s. reveals the presence of four allopatric genetic lineages: North American-Far East Asian, Western Mediterranean, Australian, and an Eastern Mediterranean lineage represented by a single isolate. Geographically orientated substructure is also apparent within the three best sampled lineages. Surprisingly, given this strong phylogeographic structure, B. plicatilis s. s. shows a significant correlation between geographic and genetic distance on a global scale ('isolation by distance' – IBD. Conclusion Despite its cosmopolitan distribution and potential for high gene flow, B. plicatilis s. s. is strongly structured at a global scale. IBD patterns have traditionally been interpreted to indicate migration-drift equilibrium, although in this system equilibrium conditions are incompatible with the observed genetic structure. Instead, we suggest the pattern may have arisen through persistent founder effects, acting in a similar fashion to geographic barriers for larger

  2. 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.

  3. Temporal and spatial distribution of the meiobenthic community in Daya Bay, South China Sea

    Science.gov (United States)

    Tang, L.; Li, H. X.; Yan, Y.

    2012-04-01

    Spatial and temporal biodiversity patterns of the meiobenthos were studied for the first time in Daya Bay, which is a tropical semi-enclosed basin located in the South China Sea. The abundance, biomass, and composition of the meiobenthos and the basic environmental factors in the bay were investigated. The following 19 taxonomic groups were represented in the meiofauna: Nematoda, Copepoda, Polychaeta, Oligochaeta, Kinorhyncha, Gastrotricha, Ostracoda, Bivalvia, Turbellaria, Nemertinea, Sipuncula, Hydroida, Amphipoda, Cumacea, Halacaroidea, Priapulida, Echinodermata, Tanaidacea, and Rotifera. Total abundance and biomass of the meiobenthos showed great spatial and temporal variation, with mean values of 993.57 ± 455.36 ind cm-2 and 690.51 ± 210.64 μg 10 cm-2, respectively. Nematodes constituted 95.60 % of the total abundance and thus had the greatest effect on meiofauna quantity and distribution, followed by copepods (1.55 %) and polychaetes (1.39 %). Meiobenthos abundance was significantly negatively correlated with water depth at stations (r=-0.747, P<0.05) and significantly negatively correlated with silt-clay content (r=-0.516, P<0.01) and medium diameter (r=-0.499, P<0.01) of the sediment. Similar results were found for correlations of biomass and abundance of nematodes with environmental parameters. Polychaete abundance was positively correlated with the bottom water temperature (r=0.456, P<0.01). Meiobenthos abundance differed significantly among seasons (P<0.05), although no significant difference among stations and the interaction of station × season was detected by two-way ANOVA. In terms of vertical distribution, most of the meiobenthos was found in the surface layer of sediment. This pattern was apparent for nematodes and copepods, but a vertical distribution pattern for polychaetes was not as obvious. Based on the biotic indices and analyses of their correlations and variance, the diversity of this community was likely to be influenced by

  4. Preliminary assessment of the zooplankton community composition in a region under the influence of a uranium mine (Caldas, Southeastern Brazil)

    International Nuclear Information System (INIS)

    Ferrari, Carla Rolim; Roque, Claudio Vitor; Ronqui, Leilane B.; Campos, Michelle B.; Rodgher, Suzelei; Nascimento, Marcos Roberto Lopes; Azevedo, Heliana de; Wisniewski, Maria Jose dos Santos

    2009-01-01

    The Ore Treatment Unit consists of an open cast mine (CM), its mining waste areas, facilities for the physical treatment of the ore, and a chemical treatment plant for uranium extraction. At CM, the processes of acid drainage create effluents, which are treated by chemical processes and, thereafter, disposed of in Antas dam. The objective of the present study was to make an inventory of zooplanktonic and describe the physicochemical characteristics of site CM and at the site of treated effluents disposal (site 41), located at Antas dam. Water samples were collected in October/08 and January/09, in order to describe the abiotic variables and the zooplankton community. The average values of conductivity at sites CM and 41 were 2415 and 422 μ/cm 2 , respectively. Values of pH at site CM remained acid, whereas, at site 41 we recorded values near neutrality. The concentrations of total nutrients at both sampling sites were higher in the rainy season. Zooplankton species richness present at site CM was lower than at site 41, and there were only two identified species Bosmina sp and Keratella americana. At site 41 we recorded more species, mainly of the Rotifera. Among Cladocera, we identified two species, regarding Copepoda, the orders Cyclopoida and Calanoida were present. At site CM the density values were lower compared to site 41. The preliminary assessment of the zooplankton community showed lower values of species richness and density at site CM, what may be probably explained by the adverse environmental conditions for zooplankton community. (author)

  5. Application of the biotic ligand model to explain potassium interaction with thallium uptake and toxicity to plankton.

    Science.gov (United States)

    Hassler, Christel S; Chafin, Ryan D; Klinger, Mary Beth; Twiss, Michael R

    2007-06-01

    Competitive interaction between TI(I) and K was successfully predicted by the biotic ligand model (BLM) for the microalga Chlorella sp. (Chlorophyta; University of Toronto Culture Collection strain 522) during 96-h toxicity tests. Because of a greater affinity of T1(I) (log K = 7.3-7.4) as compared to K (log K = 5.3-6.3) for biologically sensitive sites, an excess of 40- to 160-fold of K is required to suppress T1(I) toxic effects on Chlorella sp., regardless of [T1(I)] in solution. Similar excess of K is required to suppress T1(I) toxicity to Synechococcus leopoliensis (Cyanobacteria; University of Texas Culture Collection strain 625) and Brachionus calyciflorus (Rotifera; strain AB-RIF). The mechanism for the mitigating effect of K on T1(I) toxicity was investigated by measuring 204T1(I) cellular uptake flux and efflux in Chlorella sp. Potassium shows a competitive effect on T1(I) uptake fluxes that could be modeled using the BLM-derived stability constants and a Michaelis-Menten relationship. A strong T1 efflux dependent only on the cellular T1 concentration was measured. Although T1 efflux does not explain the effect of K on T1(I) toxicity and uptake, it is responsible for a high turnover of the cellular T1 pool (intracellular half-life = 12-13.5 min). No effect of Na+, Mg2+, or Ca2+ was observed on T1+ uptake, whereas the absence of trace metals (Cu, Co, Mo, Mn, Fe, and Zn) significantly increased T1 uptake and decreased the mitigating effect of K+. The importance of K+ in determining the aquatic toxicity of T1+ underscores the use of ambient K+ concentration in the establishment of T1 water-quality guidelines and the need to consider K in predicting biogeochemical fates of T1 in the aquatic environment.

  6. Estudio de la composición y abundancia del zooplancton durante la fase de llenado del embalse Amaní, Norcasia (Caldas

    Directory of Open Access Journals (Sweden)

    Juan Pablo Álvarez Silva

    2003-01-01

    Full Text Available La variación de la composición, abundancia y diversidad del zooplancton fue analizada durante la fase de llenado del embalse Amaní en un gradiente horizontal y vertical, a partir de trece muestreos semanales realizados entre junio y agosto de 2002. La composición del zooplancton es similar a otros ecosistemas lénticos tropicales de baja altitud y fue registrado un total 32 taxa, de los cuales se destaca el rotífero Keratella por su elevada abundancia durante junio y julio. Rotifera fue el grupo que presentó la mayor riqueza de especies (16 así como una sobresaliente dominancia numérica sobre copépodos y cladóceros, con una abundancia relativa superior al 60%. La densidades promedio del zooplancton fluctuaron de manera significativa (6 a 1525 org l-1, y de forma diferencial entre los brazos del embalse y los sectores de confluencia y presa, que presentaron los menores intervalos (14-208 org l-1 y 6-108 org l-1, respectivamente. En el presente trabajo se incluyen los patrones de comportamiento de la abundancia de los géneros más frecuentes de zooplancton así como de aspectos relacionados con la dinámica poblacional de los copépodos Thermocyclops decipiens y Mesocyclops aspericornis. Se discuten los cambios en la estructura de la comunidad del zooplancton y se mencionan las posibles interacciones y fenómenos de regulación entre los diferentes taxa zooplanctónicos y de estos con el fitoplancton. Finalmente se presenta un catalogo de microfotografías de los organismos registrados. Este trabajo constituye un aporte importante de ecología descriptiva del zooplancton limnético y da pautas para posteriores monitoreos en este embalse.

  7. The temporal dynamics of zooplankton communities of different types of water bodies within Ichniansky National Park

    Directory of Open Access Journals (Sweden)

    Z. V. Burian

    2017-05-01

    Full Text Available In recent decades, the influence of anthropogenic impact on aquatic ecosystems has increased. This has led to a restructuring of aquatic ecosystems and affected the structural and functional organization of groups of aquatic organisms, causing qualitative and quantitative changes. Particular attention is drawn to the different types of water bodies of protected areas like IchnyanskyNational Park, which is located in Ichnyansky district of Chernihiv region. This park is a newly created one, so the reduction in intensity of anthropogenic pressure can be traced within its waters. Zooplankton plays an important role in the functioning of trophic networks because it transfers energy from producers and primary consumers to young fish and planktonophagous fish. Therefore, three main groups of zooplankton were chosen as the object of study: rotifers (class Eurotatoria, cladocerans (class Branchiopoda, order Cladocera, different age stages of copepods (class Copepoda, and also ostracods (Class Ostracoda. The zooplankton used as research material was collected in the daytime in spring (April, summer (late July – early August and autumn (late September – early October in the years 2015–2016 from ten experimental stations. During this period 81 species of zooplankton were recorded within heterogeneous reservoirs of IchnianskyNational Park. Monogonont rotifers (subclass Monogononta included 35 species (43% of all species and bdelloid rotifers (subclass Bdelloidea, cladocerns, comprised 28 species (35%, and copepods included 18 species (22%. The faunal range of zooplankton over different years and seasons was characterized by the predominance of the rotator complex in spring, rotator-cladocerans and cladocerans in summer, and of the cladocerans complex in autumn. This was due to the formation during spring and summer of favourable conditions in the waters for filter feeders, which consist generally of rotifers and cladocerans. In autumn the water

  8. EVALUACIÓN DE LA ROTIFEROFAUNA PRESENTE EN EL COMPLEJO DE PAJARALES DURANTE LA ÉPOCA LLUVIOSA, DEPARTAMENTO DE MAGDALENA, COLOMBIA

    Directory of Open Access Journals (Sweden)

    SEBASTIÁN CELIS

    2008-05-01

    Full Text Available Con miras a evaluar posibles efectos de la recomunicación del río Magdalena con su antiguo delta, se determinó la abundancia y composición de la rotiferofauna del Complejo de Pajarales (CP, durante el período de mayor abundancia anual de zooplancton. El phylum Rotifera fue seleccionado por sus altas tasas reproductivas y eficiencia en procesos de transformación energética. Las muestras se colectaron con botella van Dorn durante la segunda temporada lluviosa de 2006. En cada una de las cuatro estaciones analizadas se registraron la salinidad, temperatura, pH y oxígeno disuelto. La diversidad se calculó empleando el índice de Shannon-Wiener H’ (log10 comparando estaciones y fechas de muestreo para establecer variaciones en el período de estudio. Gráficamente se relacionaron variables fisicoquímicas con valores de diversidad que emplearon un α de 0.05 y 95% de intervalo de confianza. En total, fueron encontrados 20 morfotipos pertenecientes a las familias Brachionidae, Lecanidae, Filiniidae, Synchaetidae, Hexarthriidae y Testudinellidae, siendo Brachionidae y Lecanidae las más abundantes. La relación entre diversidad y variables fisicoquímicas, indica que la salinidad es la principal responsable de la diversidad de rotíferos. En conclusión, la rotiferofauna actual en el CP es más abundante y diversa que hace 16 años, antes de la recomunicación con el río Magdalena. Así mismo, la concentración de oxigeno disuelto, pH y salinidad son diferentes. Teniendo en cuenta que la salinidad es el factor que más influyó en la diversidad de rotíferos, la reapertura de canales probablemente favoreció el incremento en la diversidad de rotíferos en el CP.

  9. Modern and fossilized biological communities from sediments of Bolshoy Harbei lake (Bolshezemelskaya tundra, Russia) and their response to climate change

    Science.gov (United States)

    Tumanov, Oleg; Nazarova, Larisa; Fefilova, Elena; Baturina, Maria; Loskutova, Olga; Frolova, Larisa; Palagushkina, Olga

    2013-04-01

    High-altitude regions are subjected to the threats of global warming. During the last decade the depth of seasonal melting of permafrost in Northern Russia, significantly increased. Investigation of lake sediments from polar regions has an extreme importance for understanding of the modern environmental processes and their influence on northern ecosystems and biological diversity of these regions. Invertebrate communities are used for diagnostic of lake ecosystems because they have a great sensitivity to climatic changes (Andronnikova, 1996; Lazareva, 2008; O'Brien et al., 2005). The data can be used as well as a basis for inference models for reconstruction of the paleoclimatic conditions. Chironomid-based, Cladocera-based and diatom models have successfully been developed (Nazarova et al., 2008, 2011; Self et al., 2011) and can be used for precise paleotemperature reconstructions (Kienast et al., 2011). In summer 2012, we investigated complex of Kharbei lakes, located in the interfluve of Korotaiha and Bolshaya Rogovaya rivers in the east side of Bolshezemelskaya tundra, Russia (67°33'22″ N, 62°53'23″ E). Six different lakes were investigated using modern hydrobiological and palaeoecological methods. In total 9 cores were obtained, cut, dated and further investigated using sedimenthological, geochemical, and paleobiological methods. The standard hydrobiological methods have shown that the modern zooplankton communities did not change significantly during the last 40 years. Taxonomic composition and structure of planktonic communities didn't change, except for appearance of crustaceans Polyarthra euryptera and Daphnia cucullata. In planktonic communities of Bolshoy Harbei lake we revealed 39 species and forms of Rotifera, 19 - Cladocera and 11 - Copepoda. In zoobenthic communities we registered 24 taxonomical groups characteristic for large tundra lakes of the North East of Russia. Chironomids and Oligochaeta are dominant groups of invertebrates. 103 taxa of

  10. Selectividad del zooplancton y solapamiento trófico entre tallas del pez Menidia humboldtiana (Atheriniformes: Atherinopsidae en el embalse Danxhó, México

    Directory of Open Access Journals (Sweden)

    Regina Sánchez Merino

    2009-06-01

    Full Text Available El charal Menidia humboldtiana es considerado como una de las especies de gran importancia en la industria pesquera de algunos estados de México. Es necesario conocer el efecto que esta especie ejerce sobre su alimento para saber si seleccionan las presas de mayor talla, si hay competencia por el alimento entre especies nativas e introducidas, y para comprender el comportamiento del zooplancton ante peces zooplanctófagos. Se determinó si M. humboldtiana selecciona su alimento, sobre qué géneros lo hace, y si existe traslape en la dieta entre las diferentes tallas. Los peces se recolectaron por medio de un chinchorro de 88 mm de abertura de malla, en seis estaciones de muestreo durante un año, en el embalse Danxhó, y una muestra de zooplancton fue recolectada por filtrado con una red de 125 µm. El análisis de los contenidos estomacales se realizó en peces agrupados en intervalos de longitud estándar para cada época del año, por medio del método volumétrico. Para evaluar el traslape trófico entre los diferentes intervalos de longitud, se utilizó el índice de Morisita modificado por Horn. El zooplancton estuvo representado por doce géneros: Mastigodiaptomus y Cyclops (Copepoda; Bosmina, Diaphanosoma, Daphnia, Ceriodaphnia, Moina, Alonopsis y Camptocercus (Cladocera; Asplanchna, Conochillus y Filinia (Rotifera. Durante la primavera, los charales de 3-8.9 cm presentaron un marcado traslape, para el verano fueron los grandes (7-10.9 cm, en otoño el traslape fue en todas las tallas, y en invierno solo las tallas intermedias (5-8.9 cm lo presentaron.Selectivity of zooplankton and trophic overlap between size Menidia humboldtiana fish (Atheriniformes: Atherinopsidae in the reservoir Danxhó, Mexico. The Menidia humboldtiana silverside is considered one of the most important species in fisheries in some states of Mexico. Knowing the choice that this species exercises over its food gives us an understanding of the behavior of

  11. Condition factor and diet of Chrysichthys nigrodigitatus and Chrysichthys auratus (Siluriformes: Bagridae from Aiba Reservoir, Iwo, Nigeria

    Directory of Open Access Journals (Sweden)

    Oluwatosin Ebenezer Atobatele

    2011-09-01

    Full Text Available Chrysichthys nigrodigitatus and C. auratus are important, highly valued and threatened freshwater species. To contribute with their ecological knowledge, the condition factor and diet of these two congeneric species were studied between April 2005 and April 2006. Food items of fish were evaluated by occurrence and numerical abundance methods, and the possible changes among sexes, seasons and sizes were considered. Results showed that generally C. nigrodigitatus were better conditioned than C. auratus. The males of C. nigrodigitatus and females of C. auratus were in better condition than their respective opposite sex throughout the year, and during the wet season compared to the dry. The food items of C. nigrodigitatus and C. auratus were similar and comprised twelve species belonging to five groups: Insecta (three species, Crustacea (five species, Arachnida (one species, Rotifera (one species and Mollusca (two species. Other food items included fish scales, unidentified green eggs, plant parts, detritus and sand. Insecta and Crustacea dominated the food items in both species. For C. nigrodigitatus, insect consumption increased with fish size, while Crustacea items decreased (from 89.59% for 8.1cm - 12.0cm size class to 1.58% for 20.1cm - 26.0cm size class. However, while C. auratus smaller sized fish preferred Crustacea (98.72% for 8.1cm -12.0cm size class, larger sized fish had both groups in relatively similar amounts. Schoener Overlap Index for both species and between seasons is 1.00. Diet breadth ranged from 0.00-1.47 for C. nigrodigitatus and 0.00-1.32 for C. auratus. Food Richness ranged from 0.00-1.44 for both species. Gut Repletion Index for C. nigrodigitatus and C. auratus are 76.39% and 76.27% respectively. Although, there is considerable similarity and overlap in the utilization of food resource for both coexisting species, condition factor and feeding behavior suggest strategies to reduce intra- and inter-specific competition. Rev

  12. Effects of liming and development of Curimbatá (Prochilodus lineatus larvae on the abundance of zooplankton in fish ponds Efeitos da calagem e desenvolvimento do Curimbatá (Prochilodus lineatus na abundância do zooplâncton em viveiros de piscicultura

    Directory of Open Access Journals (Sweden)

    Thécia Alfenas Silva Valente Paes

    2011-12-01

    Full Text Available AIM: We aimed to evaluate the influence of the correction of the water alkalinity in the fish ponds on the density of zooplankton under a period they were stocked with larvae of Prochilodus lineatus, a neotropical fish called "Curimbatá". METHODS: We used a factorial design completely randomized. In one plot (2 ponds there was no correction of the alkalinity of the water (20 mg CaCO3.L-1 and in two others, this variable was adjusted weekly to values around 30 and 60 mg CaCO3.L-1 ¹, with two replicates each. Zooplankton was sampled weekly and the experiment lasted 63 days. RESULTS: Significant differences in the density of the zooplankton over time (F = 6.78, p OBJETIVO: Nosso objetivo foi avaliar a influencia da correção da alcalinidade da água em viveiros de piscicultura na densidade do zooplâncton em período em que foram estocados com larvas de Prochilodus lineatus, um peixe neotropical denominado "Curimbatá". MÉTODOS: Foi utilizado um delineamento experimental fatorial, inteiramente causualizado. Em um tratamento (2 viveiros, não houve correção da alcalinidade da água, e em outros dois viveiros, a alcalinidade foi ajustada semanalmente para valores em torno de 30 e 60 mg CaCO3.L-1, com duas réplicas cada. Os organismos zooplanctônicos foram coletados semanalmente durante 63 dias. RESULTADOS: Diferenças significativas foram observadas na densidade do zooplâncton ao longo do tempo (F = 6,78, p < 0,05 e um decréscimo acentuado na densidade do zooplâncton foi observado da primeira para a segunda semana, e pequenos aumentos sucessivos na densidade da quarta semana até o final do experimento. Ao considerar todo o período experimental, a alcalinidade corrigida para 60 mg CaCO3.L-1 resultou em maiores densidades de zooplâncton. Ocorreram grandes mudanças na composição zooplanctônica. Rotifera foram dominantes no início do experimento e Cladocera e Copepoda nas últimas semanas, possivelmente devido a uma interação da

  13. Top-down control in a tropical shallow lake of Northern Pantanal, Brazil Controle descendente em um lago tropical raso do Pantanal Norte, Brasil

    Directory of Open Access Journals (Sweden)

    Roberto de Moraes Lima Silveira

    2010-12-01

    Full Text Available AIM: To test the effect of fish exclusion over zooplankton and phytoplankton in a shallow lake in the floodplains of the Cuiabá River in Brazil's Pantanal; METHODS: Fishes and two classes of zooplankton sizes were excluded using mesocosms (100 µm and 200 µm mesh openings. The experiment lasted nine days with sampling at the beginning, six and nine days after the start of the experiment. Zooplankton and phytoplankton densities were compared among exclusion treatments and the open water which was considered as control areas by a Repeated Measures Analysis of Variance; RESULTS: The zooplankton composition and densities differed considerably between the exclusion treatments and the control areas, with a predominance of Cladocera and Copepoda in the exclusion treatments and a predominance of Rotifera in the control areas. During the experiment, the composition of the phytoplankton assemblage showed no difference between the exclusion and the control. However, there was a marked reduction in the density of the Cyanophyta and Chlorophyta algae among the exclusion treatments; CONCLUSIONS: The increase in density and the variation in the zooplankton composition suggest that these organisms are controlled by the fish and demonstrate that the zooplankton may exert control over the density of phytoplankton.OBJETIVO: Testar o efeito da exclusão de peixes sobre o zooplâncton e o fitoplâncton em um lago da planície de inundação do Rio Cuiabá, Pantanal; MÉTODOS: Peixes e duas categorias de tamanhos de zooplâncton foram excluídos utilizando tanques mesocosmos (com aberturas de malhas de 100 µm e 200 µm. O experimento teve nove dias de duração, com amostragens realizadas no início e seis e nove dias após o início do experimento. As densidades do zooplâncton e fitoplâncton foram comparadas entre os tratamentos de exclusão e áreas abertas da lagoa, que foram consideradas áreas controle, por uma Análise de Variância com Medidas Repetidas

  14. Trophic ecology of the freshwater prawn, Pseudopalaemon bouvieri (Decapoda: Palaemonidae in Northeastern Argentina: with remarks on population structure

    Directory of Open Access Journals (Sweden)

    Romina Patricia Carnevali

    2012-03-01

    Full Text Available Freshwater decapod crustaceans are important components of food webs in these environments, but little is known about the diet of species that live in tropical waters. We studied the feeding ecology of the prawn Pseudopalaemon bouvieri and its population structure in two different areas with six lagoons, with a different composition and abundance of aquatic macrophytes. At each site of macrophytes banks, 18 prawns sample was collected with a hand net (1mm mesh size from 1m². In the laboratory, prawns cephalothorax length was measured, sex determined, and a total of 208 stomachs were examined for food items. Our results showed that the population abundance varied between 10 ind/m² and 1 411 ind/m². The cephalothorax length ranged between 6mm and 21mm, and the male:female ratio varied between 0.3 and 1.0, with a higher proportion of ovigerous females (21% in area one than area two. P. bouvieri is omnivorous, and its diet was principally based on algae, plant remains, Protozoa, Rotifera, Oligochaeta, Crustacea, Insecta, detritus and other items. The analysis of the stomach content did not reveal any significant difference in the diet between juveniles and adults, and males and females of both areas consumed a similar diet (Kruskal-Wallis test p=0.8273. We concluded that the dietary items consumed by prawns and the niche breadth were similar between the two areas, although the proportion of items consumed varied between lagoons of both areas. The density of P. bouvieri was different between areas, but the size of cephalothorax (CL was similar.Los crustáceos decápodos de agua dulce son un componente importante de la cadena trófica, pero poco se sabe sobre la dieta de las especies que viven en aguas tropicales. Nosotros estudiamos la ecología alimentaria del camarón Pseudopalaemon bouvieri y la estructura de su población en dos áreas diferentes con seis lagunas, con una diferente composición y abundancia de macrófitas acuáticas. En cada