347 research outputs found

    The All-Data-Based Evolutionary Hypothesis of Ciliated Protists with a Revised Classification of the Phylum Ciliophora (Eukaryota, Alveolata)

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    This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ The file attached is the published version of the article

    Food and feeding habits of Synodontis nigrita from the Osun River, SW Nigeria

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    An investigation was conducted into the food and feeding habits of Synodontis nigrita from the Osun River near Epe, Lagos, Nigeria. The food items in the stomach of the S. nigrita covered a wide spectrum, ranging from various types of plankton to invertebrates and plants. A seasonal variation was also noted in the stomach contents of S. nigrita over the period of investigation. The predominant food items found in the stomach were Polycystis spp., Closterium spp., Oedogonium spp., plant tissues, insect parts and detritus. This suggests that S. nigrita is an omnivore.Feeding behaviour, Stomach content, Food consumption, Nigeria, Synodontis nigrita

    Food and feeding habits of Synodontis nigrita from the Osun River, SW Nigeria

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    An investigation was conducted into the food and feeding habits of Synodontis nigrita from the Osun River near Epe, Lagos, Nigeria. The food items in the stomach of the S. nigrita covered a wide spectrum, ranging from various types of plankton to invertebrates and plants. A seasonal variation was also noted in the stomach contents of S. nigrita over the period of investigation. The predominant food items found in the stomach were Polycystis spp., Closterium spp., Oedogonium spp., plant tissues, insect parts and detritus. This suggests that S. nigrita is an omnivore

    Diversity of free-living ciliates in the sandy sediment of a Spanish stream in winter

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    This study had two objectives: to determine the number of (phenotypic) ciliate species co-existing in 1 m2 of sandy river sediment at a maximum temperature of 4 "C; and to determine the ecological mechanism(s) facilitating their co-existence. The ciliate community was diverse (65 species [8 of which are new], belonging to 50 genera, from 17 orders). The sediment supported a superficial mat of diatoms (> 30 species). These served as food for at least 16 ciliate species. The size frequency distribution of ingested diatoms was almost identical to that for the diatoms in the sediment: thus the probability of a diatom being ingested appears to be a simple function of its relative abundance. Two factors were probably important for the co-existence of ciliate species : wide variation in cell size and shape enabled them to occupy most habitats; and they deployed a variety of feeding mechanisms to consume the variety of microbial food types. Taken as a whole, the ciliate community was capable of feeding on all microbes, including other protozoa, up to a size of about 80 pm. Considering the broad diversity of ciliate habitats available within 1 m2, the importance of physical transport processes in the river basin, and the known cosmopolitan distribution of many ciliate species, it is believed likely that the species richness we recorded is representative of the expanse of sandy sediment in this river, on this occasion

    The diversity and ecological role of protozoa in fresh waters

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    Protozoa feed on and regulate the abundance of most types of aquatic microorganisms, and they are an integral part of all aquatic microbial food webs. Being so small, aerobic protozoa thrive at low oxygen tensions, where they feed (largely unaffected by metazoan grazing) on the abundance of other microorganisms. In anaerobic environments, they are the only phagotrophic organisms, and they live in unique symbiotic consortia with methanogens, sulphate reducers and non-sulphur purple bacteria. The number of extant species of protozoa may be quite modest (the global number of ciliate species is estimated at 3000), and most of them probably have cosmopolitan distributions. This will undoubtedly make it easier to carry out further tasks, e.g. understanding the role of protozoan species diversity in the natural environment

    Composition et distribution spatio-temporelle des protozoaires ciliés dans un petit lac hypereutrophe du Cameroun (Afrique centrale)

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    La composition et la distribution spatio-temporelle des ciliés du Lac Municipal de Yaoundé (Cameroun) ont été analysées d’avril à décembre 1997, en relation avec des paramètres physico-chimiques du milieu. Trois stations pélagiques et l’herbier littoral ont été échantillonnés. 58 espèces de protistes ciliés ont pu être identifiées, parmi lesquelles environ 60 % d’espèces littorales et périphytiques et 37 % d’espèces pélagiques. Les espèces les plus courantes sont les espèces pélagiques Uronema nigricans et Coleps hirtus. L’abondance saisonnière des ciliés a atteint une valeur maximale de 21 800 ind•L-1, les valeurs les plus élevées étant enregistrées dans la couche trophogène du lac, particulièrement au cours de la grande saison des pluies. Les variations de la biomasse totale des ciliés sont plus faibles, avec des maxima correspondant également aux fortes pluies. Les espèces dominantes en matière de biomasse sont Prorodon africanum, Coleps hirtus et Uronema nigricans. Enfin, les fluctuations saisonnières de l’abondance et de la biomasse des ciliés sont discutées en relation avec les paramètres environnementaux, parmi lesquels le régime pluvial tient apparemment un rôle central.The Municipal Lake of Yaoundé (3° 51’ 37’’ N and 11° 30’ 40’’ E) is a shallow water body (Zm = 4.3 m), situated in downtown Yaoundé, the political capital of Cameroon (Central Africa). The composition and the spatio-temporal distribution of ciliates in combination with physical and chemical water variables were measured in this lake from April to December 1997. Sampling was carried out weekly, at 5 depths (surface, 0.5 m, 1 m, 1.5 m and 2.5 m) and at 3 pelagic stations, A, B and C, representing the upper, middle and the lower parts of the lake, using a Van Dorn sampling bottle. In the littoral station, the periphytic fauna is collected by agitation of the vegetation in a bucket and filtration of water. The water temperature was measured with a thermometer and the pH was measured in the field with a portable pH-meter. The oxygen concentration was determined according to the Winkler method and the transparency of the water column was determined with a Secchi disk. Light availability was measured with a luxmeter. Water colour, suspended solids and ammonium-nitrogen (NH4-N) were analyzed spectrophotometrically using APHA methods. Ciliate species were identified using appropriate and specific keys and were counted under a stereomicroscope at magnifications of 250X and 500X.Results showed that the lake was hypereutrophic. Throughout the study, the temperature and pH values of the water remained around 25°C and 7, respectively. The dissolved oxygen concentration decreased with depth to almost zero at the lake bottom, while the Secchi disk transparency did not exceed 1 m. Spatio-temporal variations of these variables indicated that the middle zone (0.5 to 1.5 m) was the stratum with a critical role in the functioning of the lake. Indeed, it represented the transitional zone between the trophogenic upper layer where photosynthetic activity occurred and the bottom water layer, formed by the microaerophilic to anaerobic tropholitic layers where reducing processes were important.Fifty-eight ciliate species, belonging to 10 orders and 28 families, were identified among which five (Holophrya sp., Lagynophrya rostrata, Lagynophrya simplex, Pseudoprorodon sp. and Histriculus sp.) were new records for Cameroon fauna. This population contained 62% of littoral species and 37% of pelagic species respectively. Within these taxa, dominant species were Uronema nigricans (present at all pelagic stations) and Coleps hirtus (present at more than 97% of the pelagic stations). Their abundance was greater than 2,000 ind•L-1 during the study period showing variation with many peaks. Prorodon africanum occurred sporadically between October and November when rainfall decreased and their densities reached 5,700 ind•L-1 in November at 0.5 m depth at station A. After November, this species was replaced by Prorodon sp. Most of the species collected were cosmopolite or characteristic of shallow tropical water bodies.The total abundance of the ciliate community was high reaching 21,800 ind•L-1 at station A, at 0.5 m depth. According to several authors, the abundance of ciliates in such tropical water bodies varies from 3.6 to 9.75 x 104 ind•L-1. The highest abundances were observed at depths of 0.5 m to 1.5 m at all 3 stations, especially during the rainy season. This corroborated the importance and the role of this stratum in the functioning of Lake Yaoundé. The lowest abundance of ciliates was observed at station A, at the bottom (2.5 m depth). The total abundance of ciliates showed one or several peaks during the period from July to November. With respect to the total biomass, the variation was more regular with generally one peak during the rainy season. At certain depths at stations B and C, several peaks were observed during the period of April to June and from September to November. The total biomass values obtained were higher than those reported by other authors. This can be explained by the fact that reported values in these latter studies were expressed as dry weight while values reported in this study were expressed as wet weight. With respect to biomass, the dominant species was Prorodon africanum (5,300 µg•L-1), followed by Coleps hirtus (3,800 µg•L-1) and Uronema nigricans (3,100 µg•L-1). The highest biomass was 130 x 105 µg•L-1, and was observed at station A, at 0.5 m depth.Generally large size ciliates were more abundant during the dry season whereas small size species were abundant during rainy season. Chilodonella uncinata and Prorodon africanum grew in surface layers (between the surface and 1 m depth) while Paradileptus conicus and Uronema nigricans preferred deep water (1 to 2.5 m depth). There was a great development of ciliates during the transitional period between the rainy and dry seasons. Moreover there was a close relationship between environmental parameters and the ciliate community. In fact, 2 to 3 physico-chemical predictors (dissolved oxygen, temperature and conductivity or pH) explained spatio-temporal distributions of different species. The variation of the total biomass in station A was explained by the dissolved oxygen concentration (r2 = 0.366; p<0.001) and by the pH (r2 = 0.274; p<0.001); at stations B and C, the variation was explained by ammonium-nitrogen (r2 = 0.178 and r2 = 0.294 for p<0.01). The most important abiotic factor that influenced the density and biomass variation of ciliate communities of Lake Yaoundé was the precipitation rate. Throughout the study, station B was the most characteristic of the structure of the ciliate community of this lake

    Spatiotemporal Variations in Abundance and Biomass of Planktonic Ciliates Related to Environmental Variables in a Temporal Pond, Argentina

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    This report describes the structure and seasonal dynamics of ciliated protozoa associated with variations in the physicochemical characteristics of the environment in a temporary pond in the Buenos Aires province, Argentina. Plankton samples were obtained and physicochemical variables measured monthly for two years. A total of 50 planktonic ciliates were recorded. The highest species richness occurred during the pond´s filling and stable-hydric phases. Upon the pond´s desiccation, the number of ciliate species decreased, with the lowest values being recorded in spring; while the highest abundance and biomass were observed before the droughts. Ciliate diversity tended to be higher after droughts but decreased with pond desiccation. Most of the ciliate species were rare and found during the filling periods. Vorticella convallaria, Pelagostrobilidium wilberti, and Coleps hirtus were dominant; Cyclidium glaucoma, Strobilidium caudatum, Pseudochilodonopsis piscatoris, Limnostrombidium viride, L. pelagicum, and Chilodonella sp. were common; and Pelagostrombidium mirabile along with Rhabdostyla sp.?an epibiont on cladocerans?were occasional. The first and the sum of all axes in canonical correspondence analysis explained a significant portion of the ciliate-data variance. The autumn and winter samples grouped together corresponding to the highest conductivities, high precipitations, and low temperatures?properties characterizing the filling and stable-hydric periods. The species were distributed mainly according to conductivity and temperature gradients along the first canonical axis. The structure and temporal dynamics of planktonic ciliates from this temporary pond varied with the changes in physicochemical characteristics of the environment determined by flooding and desiccation.Fil: Kuppers, Gabriela Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Claps, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentin

    Effects of feedlot runoff on free-living aquatic ciliated protozoa

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    Water samples and free-living and sessite ciliated protozoa were collected at various distances above and below a stream that received runoff from a feedlot. No correlation was found between the species of protozoa recovered, water chemistry, location in the stream, or time of collection.U.S. Department of the InteriorU.S. Geological SurveyOpe

    Ciliates along oxyclines of permanently stratified marine water columns

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    Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Journal of Eukaryotic Microbiology 61 (2014): 434-445, doi:10.1111/jeu.12122.Studies of microbial communities in areas of the world where permanent marine water column oxyclines exist suggest they are ‘hotspots’ of microbial activity, and that these water features and the anoxic waters below them are inhabited by diverse protist taxa, including ciliates. These communities have minimal taxonomic overlap with those in overlying oxic water columns. Some ciliate taxa have been detected in multiple locations where these stable water column oxyclines exist, however, differences in such factors as hydrochemistry in the habitats that have been studied suggest local selection for distinct communities. We compare published data on ciliate communities from studies of deep marine water column oxyclines in Caricao Basin, Venezuela, and the Black Sea, with data from coastal, shallower oxycline waters in Framvaren and Mariager fjords, and from several deep-sea hypersaline anoxic basins (DHABs) in the Eastern Mediterranean Sea. Putative symbioses between Bacteria, Archaea, and ciliates observed along these oxyclines suggests a strategy of cooperative metabolism for survival that includes chemosynthetic autotrophy and exchanges of metabolic intermediates or end products between hosts and their prokaryotic partners.Edgcomb’s Cariaco work was a collaboration with G. Taylor (Stony Brook U.) and S. Epstein (Northeastern U.) (MCB-0348407 to VE), her DHAB work was a collaboration with J.M. Bernhard (WHOI), K. Kormas (U. Thessaly), M. Yakimov (CNRS), and T. Stoeck (U. Kaiserslautern) (NSF OCE-0849578 to VE and JMB).2015-05-0

    Fluctuation in density of ciliates in Bukan dam reservoir, Zarrinehrud, Iran

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    The abundance and species composition of ciliates were analyzed in the Bukan Dam Reservoir (West Azerbaijan, Iran) from January to December 2008. Surface water samples were collected at monthly intervals from the middle (Stations 1 and 3) and shallow (Stations 2 and 4) areas of the lake. Three samples were taken in the water column using a 5-litre sampler. Totally 30 liters water was collected, 200 ml of which was fixed immediately with 8.6 ml of a saturated HgCl2 solution and stained with 0.04% bromophenol blue. Three subsamples were counted in a 5-ml chamber and examined with a microscope (100 x) as well as Chlorophyll a and a few ecological parameters such as dissolved oxygen, pH, transperancy and water temperature were measured. Totally 50 ciliates species were found in Bukan Dam Reservoir. Regarding the density, a high-density period was detected from January to April with a mean density of 2.86 x 103 cells.l-1 Ciliata at stations 1 and 3 and 4.16 x 103 cells.l-1 at stations 2 and 4. The high density of ciliate in summer may be due to the increase in the density of bacteria and moderate metazooplankton as a result of the appearance of non-edible algae . The ciliata occurring at the highest densities were Coleps tessellates, Didinium nasutum, Paradileptus elephantinus, Stentor polymorphus, Zosterograptus labiatus, Paramecium bursaria, Cyclidium citrullus, Vorticella campanula, Halteria grandinella and Aspidisca costata. The maximum and minimum chlorophyll a values observed at the reservoir water were 10.39 µg.l-l and 1.0 µg.l-l being obtained in May and Octobor respectively
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