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| Registros recuperados: 31 | |
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| Luo, Zhaohe; Krock, Bernd; Mertens, Kenneth; Nezan, Elisabeth; Chomerat, Nicolas; Bilien, Gwenael; Tillmann, Urban; Gu, Haifeng. |
| The marine planktonic dinophyceaen genus Azadinium is a primary source of azaspiracids, but due to their small size its diversity may be underestimated and information on its biogeography is still limited. A new Azadinium species, A. zhuanum was obtained from the East China Sea and Yellow Sea of China by incubating surface sediments. Five strains were established by isolating single germinated cells and their morphology was examined with light microscopy and scanning electron microscopy. Azadinium zhuanum was characterized by a plate pattern of Po, cp, X, 4′, 2a, 6′′, 6C, 5S, 6′′′, 2′′′′, by a distinct ventral pore at the junction of Po, the first and fourth apical plates, and a conspicuous antapical spine. Moreover, Azadinium poporum was obtained for the... |
| Tipo: Text |
Palavras-chave: Azadinium; Azaspiracid; AZA-2; AZA-2 phosphate; Biogeography; China; French Atlantic; Mediterranean Sea. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00386/49765/51155.pdf |
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| Zendong, Suzie Zita; Kadiri, Medina; Herrenknecht, Christine; Nezan, Elisabeth; Mazzeo, Antonia; Hess, Philipp. |
| Algal toxins may accumulate in fish and shellfish and thus cause poisoning in consumers of seafood. Such toxins and the algae producing them are regularly surveyed in many countries, including Europe, North America, Japan and others. However, very little is known regards the occurrence of such algae and their toxins in most African countries. This paper reports on a survey of phytoplankton and algal toxins in Nigerian coastal waters. Seawater samples were obtained from four sites for phytoplankton identification, on three occasions between the middle of October 2014 and the end of February 2015 (Bar Beach and Lekki in Lagos State, Port Harcourt in Rivers State and Uyo in Akwa Ibom State). The phytoplankton community was generally dominated by diatoms and... |
| Tipo: Text |
Palavras-chave: Dinoflagellates; Dinophysis; Phycotoxins; Untargeted analysis; Phytoplankton. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00314/42521/41893.pdf |
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| Chomerat, Nicolas; Nezan, Elisabeth. |
| A new sand-dwelling dinoflagellate species, Cabra reticulata sp. nov., is described from sandy habitats in the south of Brittany (northwestern France). This new species possesses the characteristics of the 'unusual' genus, Cabra Murray et Patterson. The thecal plate formula is Po Pt 3' 1a 4'' 'x' 3c ?s 5''' 1'''' (or alternatively interpreted as Po Pt 4' 0a 4'' 'x' 3c ?s 5''' 1''''). Because of the strong lateral compression, cells of C. reticulata are frequently seen laterally and have a polygonal shape, with three prominent antapical pointed flanges and a dorsal spine in the anterior part of the hypotheca. The cingulum is ascending and incomplete. The thecal surface is ornamented with strong reticulations forming polygonal areolae, which differs from C.... |
| Tipo: Text |
Palavras-chave: Taxonomy; Sand dwelling; Roscoffia; Protists; Podolampaceae; Marine; Dinophyceae; Benthic. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6804.pdf |
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| Le Gal, Dominique; Nezan, Elisabeth; Raguenes, Pierre; Piclet, Guy. |
| Dans le cadre du Réseau de surveillance phytoplanctonique, nous nous sommes intéressés à un phénomène particulier d'eaux colorées. L'espèce responsable Chaetoceros armatum a fait l'objet d'un suivi sur plusieurs mois et les résultats exposés dans ce rapport concernent essentiellement la période février 1992 à mars 1993. Nous nous limiterons à présenter cette espèce particulière pour laquelle la bibliographie est assez pauvre, et à décrire le phénomène in situ. |
| Tipo: Text |
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| Ano: 1995 |
URL: http://archimer.ifremer.fr/doc/00017/12806/9749.pdf |
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| Nezan, Elisabeth; Bilien, Gwenael; Boulben, Sylviane; Mertens, Kenneth; Chomerat, Nicolas. |
| A new marine raphid diatom, Plagiolemma distortum Nézan, sp. nov. is described from plankton samples from the Atlantic Ocean, south Brittany (north-western France), where it was regularly observed, but never in high abundances. Cells have an unusual and complex shape under light microscopy (LM) depending on their position and orientation. The two valves are highly vaulted and narrow in width (transapical axis). Cells contain four complexly lobed plastids and a variable number of refractive granules without particular localization. In addition, capsules containing motile cells were observed. Ultrastructural details of the frustules were investigated using scanning electron microscopy (SEM). The girdle bands are simple. Each valve possesses a sigmoid raphe... |
| Tipo: Text |
Palavras-chave: Capsules; Habitat; Molecular phylogeny; Plastids; Raphid diatom; Video. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00441/55235/56797.pdf |
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| Lemonnier, Hugues; Lantoine, Francois; Courties, Claude; Guillebault, Delphine; Nezan, Elisabeth; Chomerat, Nicolas; Escoubeyrou, Karine; Galinie, Christian; Blockmans, Bernard; Laugier, Thierry. |
| Tropical shrimp aquaculture systems in New Caledonia regularly face major crises resulting from outbreaks of Vibrio infections. Ponds are highly dynamic and challenging environments and display a wide range of trophic conditions. In farms affected by vibriosis, phytoplankton biomass and composition are highly variable. These conditions may promote the development of harmful algae increasing shrimp susceptibility to bacterial infections. Phytoplankton compartment before and during mortality outbreaks was monitored at a shrimp farm that has been regularly and highly impacted by these diseases. Combining information from flow cytometry, microscopy, pigment and phylogenetic analysis, the presence of Picocyanobacteria, Prasinophyceae and Diatomophyceae were... |
| Tipo: Text |
Palavras-chave: Tropical aquaculture pond; Litopenaeus stylirostris; Vibriosis; Eutrophication; Phytoplankton; Harmful algae. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00343/45411/44986.pdf |
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| Mertens, Kenneth; Gu, Haifeng; Pospelova, Vera; Chomerat, Nicolas; Nezan, Elisabeth; Gurdebeke, Pieter; Bogus, Kara; Vrielinck, Henk; Rumebe, Myriam; Meteigner, Claire. |
| The resting cysts of the benthic dinoflagellate Prorocentrum leve from a natural reservoir in Gujan-Mestras (Gironde, France) were described in this study. The incubated urn-shaped cysts gave rise to cells of Prorocentrum leve. Morphological observations through light microscopy and scanning electron microscopy, particularly of the periflagellar platelets, combined with large subunit ribosomal DNA sequences obtained through single-cell analysis confirm their affinity to the species Prorocentrum leve. The cysts are characterized by a specific shape and the presence of an anterior plug. This is the first conclusive evidence for fossilizable resting stages within the Prorocentrales, one of the major orders within the Dinophyceae. Palynological treatments show... |
| Tipo: Text |
Palavras-chave: Cellulosic; Micro-FTIR; Palynology; Prorocentrales; Resting stage. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00398/50971/51728.pdf |
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| Tillmann, Urban; Soehner, Sylvia; Nezan, Elisabeth; Krock, Bernd. |
| Azadinium is a dinophycean genus capable of producing azaspiracids (AZAs), a recently discovered group of lipophilic phycotoxins causing human intoxication via mussel consumption. Although initially described from the North Sea, the genus currently consisting of four described species is probably distributed worldwide. Here we report on Azadinium from the Shetland Islands, which are located in the northernmost part of the North Sea and are largely influenced by the Atlantic Ocean. Two strains of Azadinium were isolated from a single water sample. One strain was identified as Azadinium spinosum based on morphology and sequence data and had an AZA cell quota of about 20 fg per cell, similar to all other described strains of the species. The toxin profile... |
| Tipo: Text |
Palavras-chave: Azadinium; Azaspiracids; New species; Shetland Islands. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00108/21963/20691.pdf |
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| Nezan, Elisabeth; Chomerat, Nicolas. |
| A new species of the genus Fragilidium, F. duplocampanaeforme sp. nov., is described from examinations by LM and SEM. This species has been recorded in summer on the French Atlantic coast, over a number of years. It was never abundant in the plankton and was very often associated with Fragilidium subglobosum, Pyrophacus horologium and also with toxigenic species of the genera Alexandrium and Dinophysis. Phagotrophy of F. duplocampanaeforme on Dinophysis prey is shown, and sexual reproduction is suggested by the observation of gamete-like small forms. The size and the peculiar shape of its cells do not correspond to any known taxon, but the plate arrangement fits the genus Fragilidium. The plate formula is Po, Pc, 4', 8 '', 10c, 6s?, 7"', 2 '''', lp. A... |
| Tipo: Text |
Palavras-chave: Taxonomy; Phagotrophy; Fragilidium duplocampanaeforme sp nov.; Fragilidium; Dinophyceae; Atlantic ocean. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6233.pdf |
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| Nezan, Elisabeth; Siano, Raffaele; Boulben, Sylviane; Six, Christophe; Bilien, Gwenael; Cheze, Karine; Duval, Audrey; Le Panse, Sophie; Quere, Julien; Chomerat, Nicolas. |
| The family Kareniaceae is mostly known in France for recurrent blooms of Karenia mikimotoi in the Atlantic, English Channel, and Mediterranean Sea and for the unusual green discoloration in the saltwater lagoon of Diana (Corsica) caused by Karlodinium corsicum in April 1994. In terms of diversity, this taxonomic group was long overlooked owing to the difficult identification of these small unarmored dinoflagellates. In this study, thanks to the molecular characterization performed on single cells from field samples and cultures, twelve taxonomic units were assigned to the known genera Karenia, Karlodinium and Takayama, whereas one could not be affiliated to any described genus. The molecular phylogeny inferred from the D1–D2 region of the LSU rDNA showed... |
| Tipo: Text |
Palavras-chave: Genetic diversity; Haemolytic; Kareniaceae; Pigments; Single cell; Taxonomy. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00225/33611/32310.pdf |
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| Lorrain, Anne; Paulet, Yves-marie; Chauvaud, Laurent; Savoye, Nicolas; Nezan, Elisabeth; Guerin, Laurent. |
| The aim of this study was to characterize the daily shell growth of Pecten maximus from early 1998 to late spring 1999 in the Bay of Brest with a careful qualitative and quantitative description of the pelagic primary production. Our results, in accordance with previous studies, demonstrate that there are episodic declines in the growth rate. Concurrent events of low growth rate and large bottom-concentrations of algae following diatom blooms (Cerataulina pelagica or Rhizosolenia delicatula), suggests that this high concentration of phytoplankton on the bottom layer may affect food intake or respiratory activity of the scallops by gill clogging or oxygen depletion. In this study, silicic acid or phosphorus are inferred to be limiting factors responsible... |
| Tipo: Text |
Palavras-chave: Biscay bay; Limiting factors; Primary production; Phytoplankton cnoncentration; Pecten maximus; Growth rate. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/publication-612.pdf |
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| Kempf, Marc; Jacq, E; Le Guellec, C; Merceron, Michel; Monfort, Patrick; Nezan, Elisabeth; Ryckaert, Mireille. |
| This document presents a year-long (1994) environmental study conducted on a site of intensive farming of salmonids (mainly fario trout) in Camaret Bay. A set of parameters were considered for the body of water and the sea bed (flow patterns, hydrology, sedimentology, biology, chemistry) and complemented by video observations. The study concluded that there was a measurable effect from the farm in its current configuration, but that the impact was of a very limited intensity and scope that did not affect the environment in a substantial way. It is recommended that production growth be accompanied by a minimum amount of environmental assessment. |
| Tipo: Text |
Palavras-chave: Bretagne; Truite fario; Salmonidés; Environnement; Pisciculture marine. |
| Ano: 1995 |
URL: http://archimer.ifremer.fr/doc/1995/rapport-2834.pdf |
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| Lema, Anais Kimberley; Latimier, Marie; Nezan, Elisabeth; Fauchot, Juliette; Le Gac, Mickael. |
| The factors responsible for inducing the synthesis of toxins and responses from toxic phytoplankton blooms remain unclear. In this study we compare the influence of genotypic (at both the intra and interspecific levels) and environmental factors (nutrient concentration and ratio) on growth (in terms of cell densities) and domoic acid (DA) production in three Pseudo-nitzschia species: P. australis, P.pungens and P.fradulenta. A strong phosphate effect was detected. More precisely, a low initial concentration in phosphate, even at high initial nitrogen and silicate concentrations, induced the highest DA concentrations and the lowest cell densities in all strains/species studied. In contrast, a low initial concentration of nitrogen and silicate combined, with... |
| Tipo: Text |
Palavras-chave: Pseudo-nitzschia strains; Domoic acid; Ratio; Phosphate; Nitrogen. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00377/48849/49397.pdf |
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| Mertens, Kenneth; Chomerat, Nicolas; Nezan, Elisabeth; Bruneau, Audrey; Le Bec, Claude. |
| Les inspections vétérinaires de la Commission Européenne ayant signifié à la France son constat d'une absence de réserau de surveillance sur les claires ostréicoles, la DGAL a mandaté l'Ifremer afin de réaliser un premier diagnostic sur le phytoplancton. Cette commande de la DGAL place l'Ifremer LERBO comme prestataire de service et spécialiste des micro-algues. Les claires ostréicoles étant hors du domaine public maritime, une concertation avec le Comité Régional de la Conchyliculture de Poitou-Charentes, la DGAL et la DDTM 17 en juin 2018 a permis de proposer six claires, réparties entre l'île de Ré et l'île d'Oléron et pouvant être échantillonnées. L'objectif est de faire un état des lieux de la présence ou de l'absence de cellules de phytoplancton... |
| Tipo: Text |
Palavras-chave: Charentes; Claire; Phytoplancton; Micro-algue; Toxine. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00486/59731/62828.pdf |
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| Lassus, Patrick; Chomerat, Nicolas; Hess, Philipp; Nezan, Elisabeth. |
| This book updates available international databases on toxic and harmful species of phytoplankton and micro-phytobenthos. It lists regional occurrences at world-wide scale: localities, cell densities, toxicity levels in contaminated animals, human and animal poisoning, isolation of identified active molecules and toxins, documentary sources. Finally, this book addresses the geographic distributions of phycotoxin-producers from recent data. The objective is to analyze the evolution of toxic and harmful episodes over the past 30 years to identify trends, and to introduce a discussion on the reality of a time-dependent increase in the number of known species and toxins. |
| Tipo: Text |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00379/49054/49508.pdf |
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| Tillmann, Urban; Gottschling, Marc; Nezan, Elisabeth; Krock, Bernd; Bilien, Gwenael. |
| Some species of the planktonic dinoflagellate genus Azadinium produce azaspiracids (AZAs), a group of lipophilic phycotoxins causing human poisoning after mussel consumption. We describe three new species from the North Atlantic, all of which shared the same Kofoidean plate pattern characteristic for Azadinium: Po, cp, X, 4′, 3a, 6′́, 6 C, 5S, 6′́́, 2′́́́. Azadinium trinitatum sp. nov. was mainly characterized by the presence of an antapical spine and by the position of the ventral pore at the left distal end of the pore plate in a cavity of Plate 1′ Plate 1. Azadinium cuneatum sp. nov. had a conspicuously formed first apical plate, which was asymmetrically elongated and tapered on its left lateral side with a ventral pore located at the tip of this... |
| Tipo: Text |
Palavras-chave: Azadinium; Azaspiracids; Irminger Sea; Iceland; New species. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00188/29917/28382.pdf |
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| Chomerat, Nicolas; Sellos, Daniel Y.; Zentz, Frederic; Nezan, Elisabeth. |
| A new marine benthic Prorocentrum species from sandy habitats of South Brittany (northwestern France), P. consutum sp. nov., is described using LM and SEM and molecular phylogenetic analyses. Cells have a subcircular to broadly ovoid shape and are plainly flattened. They are 57-61 lm long and 52-55 lm wide. A central pyrenoid is present, and the kidney-shaped nucleus is positioned in the posterior region. In right valve view, the periflagellar area is deeply excavated, and the left valve forms a prominent apical ridge. The periflagellar area consists of nine platelets, and a small narrow collar is present around the flagellar pore. The ornamentation of this new species is very peculiar and is characterized by a ring of round areolae located at the... |
| Tipo: Text |
Palavras-chave: Taxonomy; SSU rDNA; SEM; Prorocentrum; Nuclear DNA; Molecular phylogeny; LSU rDNA; Dinoflagellates. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/2010/publication-7449.pdf |
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| Registros recuperados: 31 | |
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