Consulta: creatorFacets:"Beker, Beatriz"
Registros recuperados: 8
Data/hora: 20/05/2024 05:33:32

Comparative study of three analysis methods (TTGE, flow cytometry and HPLC) for xenobiotic impact assessment on phytoplankton communities
Provedor de dados: 5
Autores: Stachowski-haberkorn, Sabine; Quiniou, Louis; Beker, Beatriz; Haberkorn, Hansy; Marie, Dominique; De La Broise, Denis.
The impacts of the fungicide Opus(A (R)) (epoxiconazole) on marine phytoplankton communities were assessed in a 12-day field experiment using in situ microcosms maintained underwater at 6 m depth. Three community analysis methods were compared for their sensitivity threshold in fungicide impact detection. When phytoplankton communities were exposed to 1 mu g l(-1) of epoxiconazole, no effects could be demonstrated using TTGE (Temporal Temperature Gradient gel Electrophoresis), flow cytometry or HPLC. When exposed to 10 mu g l(-1), TTGE fingerprints from PCR amplified 18S rDNA of communities exhibited significant differences compared with controls (ANOSIM, P = 0.028). Neither flow cytometry counts, nor HPLC pigment profiles allowed to show significant...
Tipo: Text
Palavras-chave: Microcosm; Phytoplankton community; Epoxiconazole; TTGE; Flow cytometry; HPLC.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/00088/19888/17547.pdf

Copepods Boost the Production but Reduce the Carbon Export Efficiency by Diatoms
Provedor de dados: 5
Autores: 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

Effect of local hydroclimate on phytoplankton groups in the Charente estuary
Provedor de dados: 5
Autores: Guesdon, Stephane; Stachowski-haberkorn, Sabine; Lambert, Christophe; Beker, Beatriz; Brach-papa, Christophe; Auger, Dominique; Bechemin, Christian.
This study aimed to describe seasonal variations of phytoplankton abundances in relation to the physical and chemical (nutrients and metals) environment under the influence of freshwater input in the Charente river estuary (Marennes-Oléron bay, France) over three years, from 2011 to 2014. Phytoplankton abundances were determined using microscopy and flow cytometry. Considering high frequency temperature and salinity data, breakpoints in each series led to the identification of two local hydroclimatic periods: the first (2011 and early 2012) being warmer and higher in salinity than the second (from spring 2012 to the beginning of 2014). A multiblock PLS analysis highlighted the significant contribution of the physical environment (temperature, salinity and...
Tipo: Text
Palavras-chave: Hydroclimate; Estuary; Phytoplankton; Size composition; Nutrients; Trace metals.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00349/46005/45674.pdf

Effets de l'hydroclimat local sur les groupes de phytoplancton dans l'estuaire de la Charente
Provedor de dados: 5
Autores: Guesdon, Stephane; Stachowski-haberkorn, Sabine; Lambert, Christophe; Beker, Beatriz; Brach-papa, Christophe; Auger, Dominique; Bechemin, Christian.
Cette étude s’inscrit dans le cadre du projet TOPHYPAC (2011-2014) financé par le programme “Pesticides” du Ministère de l’Écologie, du Développement durable et de l’Énergie. Ce travail vise à décrire les variations saisonnières des abondances de phytoplancton en lien avec l'environnement physique et chimique (nutriments et métaux) de l'estuaire de la Charente de 2011 à 2014. À partir des données d'abondances de groupes phytoplanctoniques déterminés par microscopie et par cytométrie de flux, les contributions relatives des variables environnementales sur la dynamique du phytoplancton ont été évaluées : dans ce but, une analyse PLS multibloc a été réalisée. Celle-ci souligne une contribution importante de l'environnement physique (température, salinité et...
Tipo: Text
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00361/47173/47139.pdf

New insights into the seasonal feeding ecology of Pecten maximus using pigments, fatty acids and sterols analyses
Provedor de dados: 5
Autores: 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

Phytoplankton phosphorus limitation in a North Atlantic coastal ecosystem not predicted by nutrient load
Provedor de dados: 5
Autores: Trommer, Gabriele; Leynaert, Aude; Klein, Cecile; Naegelen, Aurore; Beker, Beatriz.
Phytoplankton nutrient limitation patterns were investigated in an anthropogenically influenced coastal ecosystem with a high nutrient load. Weekly nutrient limitation bioassays, and water chemistry and stoichiometry measurements were performed in the Bay of Brest, France, from February to July 2011. Each limitation bioassay included phosphorus, nitrogen, silicate and all possible combined nutrient additions, and lasted over 72 h. Results showed that the phytoplankton community experienced a general P limitation from March to July. N limitation alone was observed only during 1 week in early March. Subsequently, all limitation bioassays revealed primary P limitation, indicated by significantly increased growth rates in all samples containing P additions....
Tipo: Text
Palavras-chave: Phytoplankton; Stoichiometry; Bioassays; Nutrient limitation; Coastal ecosystem.
Ano: 2013
URL: https://archimer.ifremer.fr/doc/00368/47947/48023.pdf

Possible bloom of free trichomes in the Bay of Marseille, NW Mediterranean Sea: an anomaly evidenced by flow cytometry
Provedor de dados: 5
Autores: Zhao, Li; Denis, Michel; Barani, Aude; Beker, Beatriz; Mante, Claude; Xiao, Tian; Gregori, Gerald.
The composition of ultraphytoplankton (10 m) sampled in surface waters (1 m depth) was investigated during summer 2010 in the Bay of Marseille (NW Mediterranean) using flow cytometry. In addition to groups of Synechococcus, Prochlorococcus, picoeukaryotes and nanoeukaryotes, an unidentified additional cluster was observed. The particles forming this cluster had a high abundance (7 10(4) events mL(1)), with both orange and red fluorescence intensities like Synechococcus, but with a size signal larger than that of 2 m fluorospheres (beads). These unknown particles were sorted out by flow cytometry and then observed by epifluorescence microscopy: they appeared to be chain-forming microorganisms, just like trichomes of some diazotroph cyanobacteria with one...
Tipo: Text
Palavras-chave: Ultraphytoplankton; Trichomes; Bay of Marseille; Flow cytometry; Cell sorting.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00372/48292/48454.pdf

TOPHYPAC. Tolérance des communautés phytoplanctoniques aux phytosanitaires dans le panache de la Charente. Programme Évaluation et réduction des risques liés à l’utilisation des Pesticides
Provedor de dados: 5
Autores: Stachowski-haberkorn, Sabine; Guesdon, Stephane; Bechemin, Christian; Chiffoleau, Jean-francois; Brach-papa, Christophe; Soudant, Philippe; Beker, Beatriz; Jadas-hécart, Alain.
TOPHYPAC is a field study that was conducted in the Charente river estuary (Marennes-Oléron bay). The main goal was to assess the possible impact of chemical contamination with copper and pesticides on phytoplankton communities. Physical, chemical (nutrients, metals and pesticides) and biological (phytoplankton community) parameters were monitored in the field during three years, from 2011 to 2014. In 2012 and 2013, field sampling was coupled with experimental exposure of phytoplankton communities to copper and to an herbicide cocktail, after transportation to the lab: the effects were assessed using photosynthesis endpoint and cellular densities. TOPHYPAC allowed to set the framework of Charente estuary contamination with pesticides: herbicides glyphosate...
Tipo: Text
Palavras-chave: Continuum eau douce/eau côtière; Pesticides; Métaux; Communautés phytoplanctoniques; Efficacité de photosynthèse; PICT; Tolérance; Cytométrie en flux; Toxicité chronique; Freshwater/coastal water continuum; Pesticides; Metals; Phytoplankton communities; Photosynthesis efficiency; PICT; Tolerance; Flow cytometry; Chronic toxicity.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00300/41115/40289.pdf