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Registros recuperados: 10
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Allelochemicals from Alexandrium minutum induce rapid inhibition of metabolism and modify the membranes from Chaetoceros muelleri ArchiMer
Long, Marc; Tallec, Kevin; Soudant, Philippe; Le Grand, Fabienne; Donval, Anne; Lambert, Christophe; Sarthou, Geraldine; Jolley, Dianne F.; Hegaret, Helene.
Allelochemical interactions are likely to be a contributing factor explaining the success of large blooms of the harmful marine dinoflagellate Alexandrium, however, the physiological mechanisms of allelochemical interactions remain poorly described. Here we investigated the sub-lethal effects (on an hourly scale) of a filtrate containing allelochemicals from Alexandrium minutum on the physiology of the common diatom Chaetoceros muelleri. The filtrate induced deleterious effects to the diatom physiology within only 30 min of exposure. Esterase activity and photosynthesis were drastically inhibited, with up to 34% of the population being metabolically inactive and up to 30% reduction in photosystem II quantum yield when exposed to the filtrate. In addition,...
Tipo: Text Palavras-chave: Allelopathy; Alexandrium; Metabolism; Photoinhibition; Lipids; Pigments.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00460/57133/59748.pdf
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Cadmium in the waters off South Morocco: Nature of particles hosting Cd and insights into the mechanisms fractionating Cd from phosphate ArchiMer
Waeles, Mathieu; Planquette, Helene; Afandi, Imane; Delebecque, Nina; Bouthir, Fatimazohra; Donval, Anne; Shelley, Rachel U.; Auger, Pierre-amael; Riso, Ricardo D.; De Morais, Luis Tito.
In this study, we report the distributions of total dissolvable cadmium and particulate cadmium from 27 stations in southern Moroccan coastal waters (22°N–30°N), which is part of the North-West African upwelling system. These distributions were predominantly controlled by upwelling of the North Atlantic Central Waters (NACWs) and uptake by primary production. Atmospheric inputs and phosphogypsum slurry inputs from the phosphate industry at Jorf Lasfar (33°N), recently estimated as an important source of dissolved cadmium (240 t Cd yr−1), are at best of minor importance for the studied waters. Our study provides new insights into the mechanisms fractionating cadmium from phosphate. In the upper 30 m, the anomalies observed in terms of Cd:P ratios in both...
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Ano: 2016 URL: https://archimer.ifremer.fr/doc/00334/44520/44216.pdf
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Changes in motility, ATP content, morphology and fertilisation capacity during the movement phase of tetraploid Pacific oyster (Crassostrea gigas) sperm ArchiMer
Suquet, Marc; Labbe, C.; Brizard, Raphael; Donval, Anne; Le Coz, Jean-rene; Quere, Claudie; Haffray, P..
Changes in sperm features during the movement phase are especially interesting to study in external fertilization species whose sperm duration movement is long because this implies a significant adaptation of moving cells to the external medium. This study describes the changes in tetraploid Pacific oyster sperm characteristics in relation to time post activation. Sperm individually collected on three tetraploid males were activated in seawater. Their features were analysed over a 24 h period and compared to a sperm pool collected on three diploid males as a reference. The percentage of motile spermatozoa, the intracellular ATP content, and the fine structure of spermatozoa were studied in relation to time post activation. Furthermore, the fertilisation...
Tipo: Text Palavras-chave: Crassostrea gigas; Sperm; Tetraploid; Motility; ATP; Ultrastructure.
Ano: 2010 URL: http://archimer.ifremer.fr/doc/00006/11756/8639.pdf
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Copepods Boost the Production but Reduce the Carbon Export Efficiency by Diatoms ArchiMer
Moriceau, Brivaela; Iversen, Morten H.; Gallinar, Morgane; Evertsen, Antti-jussi O.; Le Goff, Manon; Beker, Beatriz; Boutorh, Julia; Corvaisier, Rudolph; Coffineau, Nathalie; Donval, Anne; Giering, Sarah L. C.; Koski, Marja; Lambert, Christophe; Lampit, Richard S.; Le Mercier, Alain; Masson, Annick; Stibor, Herwig; Stockenreiter, Maria; De La Rocha, Christina L..
The fraction of net primary production that is exported from the euphotic zone as sinking particulate organic carbon (POC) varies notably through time and from region to region. Phytoplankton containing biominerals, such as silicified diatoms have long been associated with high export fluxes. However, recent reviews point out that the magnitude of export is not controlled by diatoms alone, but determined by the whole plankton community structure. The combined effect of phytoplankton community composition and zooplankton abundance on export flux dynamics, were explored using a set of 12 large outdoor mesocosms. All mesocosms received a daily addition of minor amounts of nitrate and phosphate, while only 6 mesocosms received silicic acid (dSi). This resulted...
Tipo: Text Palavras-chave: Biogenic silica; POC; Marine snow; Zooplankton; Mesocosm; Bay of Hopavagen; Plankton community; Biological pump.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00469/58029/60433.pdf
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Cycles saisonniers, reproduction et qualite des ovocytes chez Pecten maximus en rade de Brest ArchiMer
Paulet, Yves-marie; Bekhadra, Farida; Devauchelle, Nicole; Donval, Anne; Dorange, Germaine.
This work is part of the program, "recruitment determinism in scallops" initiated in 1992 by the "Contrat de Baie". The aim of this research was to explain interannual abundance fluctuations observed for Pecten maximus, in the Bay of Brest. To this end an analytical approach to the life cycle of the species was undertaken to determine its critical phases. A phase may be considered as "critical" if the mortality rate at its level varies from one year to the other. Using data from 1989 to 1994, a precise time-table of the "physiological year" of the scallop in the Bay of Brest was determined. Fecundity and gamete production kinetics were estimated from the annual variation in the weight indices of the gonad. In the laboratory, egg quality was estimated...
Tipo: Text Palavras-chave: Pecten maximus; Recruitment; Reproductive cycle; Digestion.
Ano: 1995 URL: http://archimer.ifremer.fr/doc/00044/15495/12861.pdf
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La plage, un univers à découvrir ArchiMer
Donval, Anne; Gobert, Bertrand; Youenou, Gilles; Loarer, Ronan.
Tipo: Text
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00028/13945/11120.pdf
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Marathon vs sprint racers: an adaptation of sperm characteristics to the reproductive strategy of Pacific oyster, turbot and seabass ArchiMer
Suquet, Marc; Cosson, J.; Donval, Anne; Labbe, C.; Boulais, Myrina; Haffray, Pierrick; Bernard, Ismael; Fauvel, Christian.
This work assesses the present knowledge on Pacific oyster sperm biology in comparison to two marine fish species (turbot and seabass) whose sperm characteristics are well described. Sperm morphology mainly differs by the presence of an acrosome in Pacific oyster which is absent in both fish species. In turbot as in Pacific oyster, a sperm maturation process along the genital tract is observed. Sperm motility is triggered by changes in osmolality for seabass and turbot and in pH for Pacific oyster. However, complementary factors are involved to maintain sperm immotile in the genital tract. Sperm movement duration is very long in Pacific oyster (2024 h), compared to turbot (35 min) and seabass (4050 s). A high capacity of ATP regeneration is observed in...
Tipo: Text
Ano: 2012 URL: http://archimer.ifremer.fr/doc/00111/22220/20059.pdf
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New insights into the seasonal feeding ecology of Pecten maximus using pigments, fatty acids and sterols analyses ArchiMer
Lavaud, Romain; Artigaud, Sebastien; Le Grand, Fabienne; Donval, Anne; Soudant, Philippe; Flye-sainte-marie, Jonathan; Strohmeier, Tore; Strand, Oivind; Leynaert, Aude; Beker, Beatriz; Chatterjee, Arnab; Jean, Fred.
We combined the use of pigments, fatty acids and sterols as biomarkers of the seasonal variation in food sources of the great scallop Pecten maximus. From March to October 2011, on a biweekly to twice-weekly basis, scallops and seawater from the water column and the water-sediment interface were collected in the Bay of Brest (Brittany, France). Pigment compositions in the seawater and in the stomach and rectum content of the scallops were analyzed by HPLC. Fatty acids and sterols from digestive gland (DG) tissue were analyzed by gas chromatography. Potential relationships between the temporal proportion of each marker in the environment and in the digestive tract were tested using multivariate analysis. Proportions of diatoms and Dinophyceae biomarkers...
Tipo: Text Palavras-chave: Trophic ecology; Food sources; Pigments; Fatty acids; Trophic marker; Phytoplankton; Pecten maximus.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00431/54244/55772.pdf
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Physiological responses of Manila clams Venerupis (=Ruditapes) philippinarum with varying parasite Perkinsus olseni burden to toxic algal Alexandrium ostenfeldii exposure ArchiMer
Lassudrie, Malwenn; Soudant, Philippe; Richard, Gaelle; Henry, N.; Medhioub, Walid; Da Silva, P.m.; Donval, Anne; Bunel, M.; Le Goïc, Nelly; Lambert, Christophe; De Montaudoin, X.; Fabioux, Caroline; Hegaret, Helene.
Manila clam stock from Arcachon Bay, France, is declining, as is commercial harvest. To understand the role of environmental biotic interactions in this decrease, effects of a toxic dinoflagellate, Alexandrium ostenfeldii, which blooms regularly in Arcachon bay, and the interaction with perkinsosis on clam physiology were investigated. Manila clams from Arcachon Bay, with variable natural levels of perkinsosis, were exposed for seven days to a mix of the nutritious microalga T-Iso and the toxic dinoflagellate A. ostenfeldii, a producer of spirolides, followed by seven days of depuration fed only T-Iso. Following sacrifice and quantification of protozoan parasite Perkinsus olseni burden, clams were divided into two groups according to intensity of the...
Tipo: Text Palavras-chave: Bivalve; Harmful algal bloom; Oxidative stress; Venerupis philippinarum; Alexandrium ostenfeldii; Perkinsus olseni..
Ano: 2014 URL: http://archimer.ifremer.fr/doc/00189/30022/28507.pdf
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The quality of great scallop (Pecten maximus) sperm after thawing ArchiMer
Suquet, Marc; Gourtay, Clemence; Donval, Anne; Le Goic, Nelly; Quere, Claudie; Malo, Florent; Le Grand, Jacqueline; Ratiskol, Dominique; Mingant, Christian; Fauvel, Christian.
Most publications devoted to the cryopreservation of mollusc sperm have focused on the definition of technical protocols, avoiding the description of sperm quality after thawing. The present study investigated the effects of cryopreservation on sperm quality in the great scallop. Wild scallop were fished during the natural spawning period and conditioned in the hatchery before use. Sperm samples were obtained after intragonadal injection of serotonin and cryopreserved using a previously published protocol. Sperm quality was assessed using a panel of four parameters: sperm motility characteristics, using a a computer assisted sperm analysis plugin with Image J, intracellular ATP content using an ATP-Lite kit, sperm integrity, using flow cytometry and sperm...
Tipo: Text Palavras-chave: Pecten maximus; Reproduction; Gamete; Sperm; Cryopreservation.
Ano: 2016 URL: https://archimer.ifremer.fr/doc/00317/42862/43912.pdf
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