Consulta: creatorFacets:"Bechemin, Christian"
Registros recuperados: 26
Data/hora: 13/06/2024 02:54:16

Nitrogen as the nutrient limiting the algal growth potential, for summer natural assemblages in the Gulf of Riga, eastern Baltic Sea
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Maestrini, Serge; Balode, Maija; Bechemin, Christian; Purina, Ingrida; Botva, Uldis.
Nutrients potentially limiting the maximal biomass of natural assemblages were studied on the basis of samples collected in late July 1997, along a transect from the mouth of the river Daugava to the central part of the Gulf of Riga. The inorganic nutrient concentrations decreased strongly between the river mouth and the central part of the gulf from 17.3 to &lt;1 mu M NO sub(3) super(-)+NO sub(2) super(-)+NH sub(4) super(+) (DIN), and from 3.5 to 0.03 mu M PO sub(4) super(3-). DIN : PO sub(4) super(3-) increased from 5 to 20. Similar trends occurred for SiO sub(3) super(2-) whose concentration decreased from 72 to 1.6 mu M, but DIN : SiO sub(3) super(2-) only halved. Comparison of DIN : P-PO sub(4) super(3-) ratios (atom : atom) with the Redfield's value...
Tipo: Text
Palavras-chave: Limiting nutrient; Algal growth potential; Natural assemblages; Gulf of Riga; Baltic Sea.
Ano: 1999
URL: http://archimer.ifremer.fr/doc/00173/28439/26771.pdf

Bilan 2015 du dispositif national de surveillance de la santé des mollusques marins
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Lupo, Coralie; Osta Amigo, Axel; Fleury, Elodie; Robert, Stephane; Garcia, Celine; Arzul, Isabelle; Baillon, Laury; Bechemin, Christian; Canier, Lydie; Chollet, Bruno; Dechamps, Lucie; Dubreuil, Christine; Faury, Nicole; Francois, Cyrille; Godfrin, Yoann; Lapegue, Sylvie; Morga, Benjamin; Travers, Marie-agnes; Tourbiez, Delphine; Masson, Jean-claude; Verin, Francoise; Cordier, Remy; Gangnery, Aline; Louis, Wilfried; Mary, Charlotte; Normand, Julien; Penot, Julia; Cheve, Julien; Dagault, Francoise; Le Jolivet, Aurore; Le Gal, Dominique; Lebrun, Luc; Bellec, Gwenael; Bouget, Jean-francois; Cochennec-laureau, Nathalie; Palvadeau, Hubert; Grizon, James; Chabirand, Jean-michel; Pepin, Jean-francois; Seugnet, Jean-luc; D'Amico, Florence; Maurer, Daniele; Le Gall, Patrik; Mortreux, Serge; Baldi, Yoann; Orsoni, Valerie; Bouchoucha, Marc; Le Roy, Valerian; Pouvreau, Stephane; Queau, Isabelle; Lamoureux, Alice.
Depuis 1992, la surveillance de la santé des mollusques marins du littoral français est assurée par le réseau de Pathologie des Mollusques (Repamo). Ses activités s’inscrivent dans le cadre de la Directive Européenne 2006/88/CE. Depuis son évaluation par la plateforme nationale d’épidémiosurveillance en santé animale en 2012, l’objectif de surveillance est la détection précoce des infections dues à des organismes pathogènes exotiques et émergents affectant les mollusques marins sauvages et d’élevage. L’année 2015 est la première année de transition pour laquelle un début d’évolution des modalités de surveillance de la santé des mollusques marins animées par l’Ifremer a été amorcé. Un dispositif hybride de surveillance a été mis en place, s’appuyant sur...
Tipo: Text
Palavras-chave: Réseau; Surveillance; Pathologie; Mollusques; Coquillages; Santé; Mortalité; Maladie.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00324/43486/42945.pdf

Relations entre apports terrigènes et conchyliculture dans les Pertuis Charentais
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Soletchnik, Patrick; Polsenaere, Pierre; Le Moine, Olivier; Guesdon, Stephane; Bechemin, Christian.
This work presents interactions between quantitative and qualitative river freshwater inputs and the shellfish farming (oyster and mussel) in the Pertuis Charentais. The quantity of freshwater (i.e. salinity) seems to have a weak influence on the shellfish farming contrarily to its quality determined by particulate and dissolved matters contained in the water. In autumn and winter, large precipitations have a "globally positive" effect amending the coastal ecosystem. Associated dissolved nutriments and the organic matter largely determine the quality of the coming spring growth for bred shellfish, itself controlling in turn the annual yield efficiencies. However, in winter their effects are postponed because of strong mineral load, low luminosity and...
Tipo: Text
Palavras-chave: Conchyliculture; Huîtres; Moules; Apports terrigènes; Zone côtière; Pertuis Charentais.; Shellfish aquaculture; Oysters; Mussels; Terrestrial inputs; Coastal zone; Pertuis Charentais.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00248/35964/34490.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: Institutional Archive of Ifreme (ArchiMer)
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

Avis sur la détection de parasites du genre Marteilia proche de l’espèce Marteilia cochillia chez les coques
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Garcia, Celine; Arzul, Isabelle; Chollet, Bruno; Serpin, Delphine; Noyer, Mathilde; Canier, Lydie; Bechemin, Christian.
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00602/71383/81205.pdf

Etude sanitaire de la zone 17.50 d'Ors-Menson, Charente-Maritime
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Noyer, Mathilde; Piquet, Jean-come; Fillon, Alain; Le Moine, Olivier; Lecadet, Cyrielle; Morin, Dimitri; Bechemin, Christian.
Suite à la demande d'exploitation de la zone d'Ors-Menson par les professionnels, la Direction Départementale du Territoire et de la Mer (DDTM) a demandé la réalisation d'une étude sanitaire en vue du classement de cette zone de production pour le groupe 2. Le classement sanitaire de la zone, demandé par le Comité Régional des Pêches et des Elevages Marins de Poitou-Charentes (CRPEM) permettra d 'ouvrir une nouvelle zone à la pêche à pied professionnelle. Cette étude réalisée par le Laboratoire Environnement Ressources des Pertuis Charentais, avec le concours des professionnels, bénéficie d'un financement de la Direction Générale de l 'Alimentation (DGAL) , du ministère de l'agriculture et de l'agro-alimentaire et de la forêt. Basée sur le paramètre...
Tipo: Text
Palavras-chave: Etude sanitaire; Contamination bactériologique des coquillages; Classement sanitaire des zones de production; E. Coli; Palourdes; Ade-Menson; Bassin de Marennes Oléron; Charente-Maritime.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00087/19777/17421.pdf

Suivi « hydrologie » et « phytoplancton » des masses d'eau du bassin hydrographique Adour-Garonne sur la période 2012-2017
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Auby, Isabelle; D'Amico, Florence; Meteigner, Claire; Rumebe, Myriam; Tournaire, Marie-pierre; Rigouin, Loic; Gouriou, Laure; Lissardy, Muriel; Sanchez, Florence; De Casamajor, Marie-noelle; Ganthy, Florian; Trut, Gilles; Trut, Florence; Caill-milly, Nathalie; Oger-jeanneret, Helene; Guesdon, Stephane; Derrien, Annick; Chabirand, Jean-michel; Genauzeau, Sylvie; Morin, Dimitri; Schmitt, Anne; Piraud, Aude; Geairon, Philippe; Grizon, James; Seugnet, Jean-luc; Thomas, Gerard; Bechemin, Christian; Bruneau, Audrey; Soudant, Dominique; Brun, Melanie; Michel, Valérie; Dupin, Michel; Bariou, Jean; Landier, Pascal; Miguel, Véronique.
Ce rapport rend compte des résultats acquis entre 2012 et 2017 sur les paramètres hydrologiques et le phytoplancton, dans le cadre des réseaux REPHY et ARCHYD (pour les points du Bassin d’Arcachon), et celui du contrôle de surveillance des masses d'eau du bassin Adour-Garonne qui ne faisaient pas l’objet de suivi avant la mise en oeuvre de la DCE. Ce document contient des résultats concernant les éléments de qualité physicochimique (oxygène dissous pour les deux types de masses d’eau, azote inorganique dissous pour les masses d’eau côtières et les masses d’eau de transition peu turbides, température et transparence pour les masses d’eau côtières exclusivement) selon des méthodes présentées dans l’annexe 1 de ce rapport. Sont également incluses dans ce...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00463/57484/59622.pdf

Avis sur la détection d'agents infectieux réglementés chez les mollusques marins en France au cours du second semestre 2018
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Garcia, Celine; Arzul, Isabelle; Canier, Lydie; Combette, Agnes; Bechemin, Christian.
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00477/58898/81058.pdf

Nutrients limiting the Algal Growth Potential (AGP) in the Gulf of Riga, eastern Baltic Sea, in spring and early summer 1996
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Maestrini, Serge; Balode, Maija; Bechemin, Christian; Purina, Ingrida; Verite, Celine.
In May, June and July 1996, samples wcre collected along one transect greatly influenced by river discharge (eastern side of the gulf), along one transect slightly influence by river discharge (western side), at one station Iocated in the mouth of the main river (River Daugava), at one station located in the center of the Gulf and at several nearshore locations of the western side. Ratios of rnolecular concentrations of in situ dissolved ioorganic nitrogen, phosphorus and silicon, as weIl as enrichment bioassays were llsed to dctcrrnine which nutrient (s) lirnited the potential biomass of phytoplankton. Both comparison of (NO.d-N02+NJ.L): P04 (DIN: DIP) values with Redfic1d's ratio and bioassay inspection led to the sarne conclusions. Phosphorus was...
Tipo: Text
Ano: 1997
URL: http://archimer.ifremer.fr/doc/00353/46409/46135.pdf

Effect of local hydroclimate on phytoplankton groups in the Charente estuary
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
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

Exoproteolytic activity determined by flow injection analysis: its potential importance for bacterial growth in coastal marine ponds
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Delmas, Daniel; Legrand, Catherine; Bechemin, Christian; Collinot, Cecile.
The measurement of the fluorescent 4-methyl-7-coumarinylamine released from the hydrolysis of a non-fluorescent peptide model substrate by exoproteolytic enzymes has been adapted to flow injection analysis (FIA). FIA allows samples to be processed very quickly (less than 2 min. for triplicate determinations) with good sensitivity (&lt; 0.1 muM) and reproducibility (relative standard deviation &lt; 3 % at the 0.2 muM level). In a coastal marine pond, exoproteolytic activity was closely related to bacterioplankton biomass. The high activity measured in pond water (maximum velocity: V(M) almost-equal-to 1.46 to 2.54 muM.h-1) emphasizes the importance of dissolved protein hydrolysis for bacterial growth and for dissolved organic nitrogen cycling. The mean...
Tipo: Text
Palavras-chave: Activité exoprotéolytique; Protéine dissoute; Analyse en flux continu; Bactérioplancton; Marais maritime; Flow injection analysis; Exoproteolytic activity; Dissolved protein; Bacterioplankton; Coastal marine pond.
Ano: 1994
URL: http://archimer.ifremer.fr/doc/00196/30756/29163.pdf

Episodes de mortalité massive de moules bleues observés en 2014 dans les Pertuis charentais
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Bechemin, Christian; Soletchnik, Patrick; Polsenaere, Pierre; Le Moine, Olivier; Pernet, Fabrice; Protat, Martin; Fuhrmann, Marine; Quere, Claudie; Goulitquer, Sophie; Corporeau, Charlotte; Lapegue, Sylvie; Travers, Marie-agnes; Morga, Benjamin; Garrigues, Manon; Garcia, Celine; Haffner, Philippe; Dubreuil, Christine; Faury, Nicole; Baillon, Laury; Baud, Jean-pierre; Renault, Tristan.
Mass mortality outbreaks (90-100%) in both juvenile and adult blue mussels were reported in 2014 along the Pertuis Charentais area of the French Atlantic coast. A series of studies were carried out to learn more about the phenomenon through detecting pathogens, describing environmental conditions and establishing the physiological status of the animals. Bacteria identif ied as belonging to the V. splendidus species were detected in dying mussels and seem able to cause mortality in blue mussels in the laboratory. Unusual environmental conditions (large amounts of fresh water, re-suspension of sediments during a series of storms, and a high renewal rate of specific water masses in Brittany’s Pertuis area) may be partially responsible for sparking the phenomen
Tipo: Text
Palavras-chave: Mortalités; Moules; Pertuis Charentais; Vibrio splendidus; Environnement; Mortality; Mussels; Pertuis Charentais; Vibrio splendidus; Environment.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00312/42343/41682.pdf

Surmortalités de la moule bleue Mytilus edulis dans les Pertuis Charentais (mars 2014)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Bechemin, Christian; Soletchnik, Patrick; Polsenaere, Pierre; Le Moine, Olivier; Pernet, Fabrice; Protat, Martin; Fuhrmann, Marine; Quere, Claudie; Goulitquer, Sophie; Corporeau, Charlotte; Renault, Tristan; Lapegue, Sylvie; Travers, Marie-agnes; Morga, Benjamin; Garriques, Manon; Garcia, Celine; Haffner, Philippe; Dubreuil, Christine; Faury, Nicole; Baillon, Laury; Baud, Jean-pierre.
Suite aux surmortalités observées au sein des élevages de moules touchant à la fois les animaux adultes et les juvéniles au mois de mars, dans les Pertuis Charentais, la Direction Générale de l’Alimentation (DGAl) a adressé une saisine à Ifremer le 04 avril 2014. Celle-ci fait état d’une demande d’appui scientifique et technique d’Ifremer pour tenter d’apporter des éléments de réponse par rapport à cette mortalité subite et importante. L’Ifremer a proposé un projet d’action permettant l’expertise du phénomène de surmortalité de la moule bleue, selon 3 axes : l’impact environnemental, la pathologie et les caractéristiques physiologiques des moules. Il s’agit de mettre en évidence la présence ou non d’agents infectieux connus ou émergents, d’apporter des...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00229/34022/32387.pdf

Effets de l'hydroclimat local sur les groupes de phytoplancton dans l'estuaire de la Charente
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
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

Phased oscillations in cell numbers and nitrate in batch cultures of Alexandrium tamarense (Dinophyceae)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Collos, Yves; Hadjadji, Imene; Plisson, Benoit; Cecchi, Philippe; Laabir, Mohamed; Bechemin, Christian; Masseret, Estelle.
Alexandrium tamarense (M. Lebour) Balech strains isolated in spring 2007 from a single bloom in Thau lagoon have been grown in nonaxenic artificial media. For three strains showing large oscillations in biomass (crashes followed by recoveries) on a scale of several days, a significant relationship was observed between changes in cell densities (as in vivo fluorescence) and changes in nitrate concentrations. Increases in cell densities were accompanied by decreases in nitrate, while decreases in cell densities corresponded to increases in nitrate, presumably due to nitrification. Net increases in nitrate could reach up to 15 mu mol N . L(-1) . d(-1) indicating a very active nitrifying archaeal/bacterial population. However, following population crashes,...
Tipo: Text
Palavras-chave: Alexandrium tamarense; Archaea; Bacteria; Decay; Growth; Nitrate; Nitrification; Oscillations.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00049/16046/13585.pdf

Dynamique hivernale des nutriments et du carbone dans les cours d’eau contrastés du Marais poitevin et flux terrestres associés en Baie de l’Aiguillon
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Polsenaere, Pierre; Le Marchand, Marie; Le Moine, Olivier; Soletchnik, Patrick; Chabirand, Jean-michel; Geairon, Philippe; Thomas, Gerard; Bechemin, Christian; Souchu, Philippe; Joyeux, Emmanuel; Le Roy, Yoann; Corre, Frédéric.
Tipo: Text
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00405/51629/52184.pdf

Suivi « hydrologie » et « phytoplancton » des masses d'eau du bassin hydrographique Adour-Garonne en 2008-2013
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Auby, Isabelle; D'Amico, Florence; Barbier, Claire; Ganthy, Florian; Maurer, Daniele; Gouriou, Laure; Rigouin, Loic; Rumebe, Myriam; Tournaire, Marie-pierre; Trut, Gilles; Oger-jeanneret, Helene; Robert, Serge; Guesdon, Stephane; Derrien, Annick; Chabirand, Jean-michel; Charpentier, Gabriel; Genauzeau, Sylvie; Schmitt, Anne; Geairon, Philippe; Grizon, James; Seugnet, Jean-luc; Thomas, Gerard; Bechemin, Christian; Soudant, Dominique; Lamoureux, Alice; Llevot, Gerard; Beaugrand, Philippe; Michel, Valerie; Dupin, Michel; Bariou, Jean; Landier, Pascal; Miguel, Véronique.
Ce rapport rend compte des résultats acquis entre 2008 et 2013 sur les paramètres hydrologiques et le phytoplancton, dans le cadre des réseaux REPHY et ARCHYD (pour les points du Bassin d’Arcachon), et celui du contrôle de surveillance des masses d'eau du district Adour-Garonne qui ne faisaient pas l’objet de suivi avant la mise en œuvre de la DCE. Ce document contient des résultats concernant les éléments de qualité physico-chimique (oxygène dissous et nutriments pour les deux types de masses d’eau, température et transparence pour les masses d’eau côtières exclusivement) selon des méthodes présentées dans une annexe de ce rapport. Sont également inclues dans ce document les données d'évaluation de la qualité des masses d'eau vis-à-vis de l'indicateur «...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00225/33615/32015.pdf

Potential environmental drivers of a regional blue mussel mass mortality event (winter 2014, Breton Sound, France)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Polsenaere, Pierre; Soletchnik, Patrick; Le Moine, Olivier; Gohin, Francis; Robert, Stephane; Pepin, Jean-francois; Stanisiere, Jean-yves; Dumas, Franck; Bechemin, Christian; Goulletquer, Philippe.
In the context of global change, increasing mariculture production has raised particular concerns regarding its environmental impact and sustainability. Molluscs and particularly blue mussel account for a significant part of this total production. Although blue mussels are considered as pretty resilient to environmental disturbances, we report in this study an unprecedented mussel mortality event that occurred during the winter 2014 in the Breton Sound. 9000 metric tonnes of mussels were lost and mortality rates up to 100% were recorded at some farming areas. Through a coupling approach, the present work aimed to better understand the potential environmental drivers associated to those mortalities. Firstly we analysed long-term in situ and satellite data...
Tipo: Text
Palavras-chave: Mytilus edulis mortalities; Climate change; Breton sound; Long-term monitoring; Hydrodynamic modelling; Vibriosis.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00376/48708/49083.pdf

Phosphorus limitation might promote more toxin content in the marine invader dinoflagellate Alexandrium minutum
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Maestrini, Serge; Bechemin, Christian; Grzebyk, Daniel; Hummert, Christian.
Alexandrium minutum (strain AM89BM) has been grown in semi-continuous culture (0.2 vol. d super(-1)) in N-limiting (NO sub(3) super(-): PO sub(4) super(3-)=1.6 and 3.16), in P-limiting (N: P=160 and 80), and in N and P balanced (N: P=16) media. The toxin content in cells changed greatly according to the N: P ratio. Cells grown in N: P balanced condition showed an average total paralytic shellfish poisoning (PSP) content of 1.24 fmol cell super(-1). In N-limiting conditions, cells contained ca. 3 times less toxin with mean values of 0.41-0.45 fmol cell super(-1). In contrast, cells grown in P-limiting conditions contained on average 3.5 and 7 times more toxins than in the balanced N: P condition: 4.31 fmol cell super(-1) in the N: P=160 medium and 8.01 fmol...
Tipo: Text
Palavras-chave: Alexandrium minutum; Phosphorus limitation; Toxin content; PSP.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/00173/28422/26753.pdf

Suivi « hydrologie » et « phytoplancton » des masses d'eau du bassin hydrographique Adour-Garonne sur la période 2009-2014
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Auby, Isabelle; D'Amico, Florence; Meteigner, Claire; Ganthy, Florian; Maurer, Daniele; Gouriou, Laure; Rigouin, Loic; Rumebe, Myriam; Tournaire, Marie-pierre; Trut, Gilles; Oger-jeanneret, Helene; Guesdon, Stephane; Derrien, Annick; Chabirand, Jean-michel; Charpentier, Gabriel; Genauzeau, Sylvie; Schmitt, Anne; Geairon, Philippe; Grizon, James; Seugnet, Jean-luc; Thomas, Gerard; Bechemin, Christian; Soudant, Dominique; Lamoureux, Alice; Beaugrand, Philippe; Noureau, Bruno; Michel, Valérie; Dupin, Michel; Bariou, Jean; Landier, Pascal; Miguel, Véronique.
Ce rapport rend compte des résultats acquis entre 2009 et 2014 sur les paramètres hydrologiques et le phytoplancton, dans le cadre des réseaux REPHY et ARCHYD (pour les points du Bassin d’Arcachon), et celui du contrôle de surveillance des masses d'eau du bassin Adour-Garonne qui ne faisaient pas l’objet de suivi avant la mise en oeuvre de la DCE.  Ce document contient des résultats concernant les éléments de qualité physicochimique (oxygène dissous pour les deux types de masses d’eau, azote inorganique dissous pour les masses d’eau côtières et les masses d’eau de transition peu turbides, température et transparence pour les masses d’eau côtières exclusivement) selon des méthodes présentées dans trois documents (Daniel, 2009 a et b ; Daniel et Soudant,...
Tipo: Text
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00280/39141/37696.pdf

Suivi « hydrologie » et « phytoplancton » des masses d'eau du bassin hydrographique Adour-Garonne sur la période 2011-2016
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Auby, Isabelle; D'Amico, Florence; Meteigner, Claire; Ganthy, Florian; Gouriou, Laure; Rigouin, Loic; Rumebe, Myriam; Tournaire, Marie-pierre; Trut, Gilles; Oger-jeanneret, Helene; Guesdon, Stephane; Derrien, Annick; Chabirand, Jean-michel; Genauzeau, Sylvie; Schmidt, Anne; Geairon, Philippe; Grizon, James; Seugnet, Jean-luc; Thomas, Gerard; Bechemin, Christian; Soudant, Dominique; Lamoureux, Alice; Provost, Charlotte; Beaugrand, Philippe; Noureau, Buno; Michel, Valérie; Dupin, Michel; Bariou, Jean; Landier, Pascal; Miguel, Véronique.
Tipo: Text
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00399/51050/51828.pdf

Interactions between a marine dinoflagellate (Alexandrium catenella) and a bacterial community utilizing reverine humic substances
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Carlsoon, Per; Edling, Hélène; Bechemin, Christian.
Dissolved organic matter in the form of riverine humic substances stimulated the growth of both axenic nitrogen-limited Alexandrium catenella cultures and nitrogen-limited cultures with a marine bacterial community present. The biomass increase of A. catenella could not be accounted for by utilization of inorganic nitrogen compounds. However, there was a considerable release of dissolved free and combined amino acids from the humic substances that was utilized by A. catenella. About 40% of the nitrogen used by A. catenella in the axenic treatment with humic substances added was taken up as organic nitrogen. Bacterial aminopeptidase and beta -glucosidase activity was stimulated by the addition of humic substances and bacterial growth increased several-fold....
Tipo: Text
Palavras-chave: Alexandrium catenella; Dinoflagellates; Bacteria; DOM; Humic substances.
Ano: 1998
URL: https://archimer.ifremer.fr/doc/00173/28431/26763.pdf

Nitrogenous organic substances as potential nitrogen sources, for summer phytoplankton in the Gulf of Riga, eastern Baltic Sea
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Maestrini, Serge; Balode, Maija; Bechemin, Christian; Purina, Ingrida.
To investigate whether uptake of dissolved organic compounds might favour the growth potential of toxic cyanobacteria and dinoflagellates, surface water was collected in late July 1997 in the Gulf of Riga, and enriched with different nitrogen sources. (1) Organic substances were added (25 mu M N) under P-, Si- and Fe-replete conditions. Urea sustained a biomass increase (protein content) 20% greater than that with NH sub(4) super(+). Glycine, hypoxanthine and putrescine gave only 50% of the biomass obtained with NH sub(4) super(+). Glutamic acid and spermine supported growth in only one case each, and guanine in none. (2) The &gt;1000 dalton fraction of dissolved organic matter (DOM) taken from the Daugava River was provided at concentrations of 5, 15 and...
Tipo: Text
Palavras-chave: Phytoplankton; Terrigenous DON; Nitrogenous nutrients; Baltic Sea.
Ano: 1999
URL: http://archimer.ifremer.fr/doc/00173/28437/26769.pdf

Rapport d'activités 2015 de l'Unité SG2M : Santé, Génétique et Microbiologie des Mollusques
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Lapegue, Sylvie; Renault, Tristan; Bechemin, Christian; Le Guyader, Soizick; Stavrakakis, Christophe; Rivet, Florence.
L’unité SG2M est structurée pour aborder de manière intégrée les domaines de la santé animale et de la santé humaine liée à production, à la consommation de coquillages, et à la qualité microbiologique du littoral. Ainsi, dans le cadre d’un continuum recherche/surveillance/expertise, et d’une approche pluridisciplinaire, l’unité cherche à développer des connaissances concernant les interactions entre agents infectieux, hôtes et environnement chez les mollusques marins, et les cycles de contamination. Dans le domaine de la recherche, les activités de l’unité sont déclinées selon quatre axes structurants : (1) la microbiologie sanitaire et les voies de transfert des agents pathogènes humains dans l’environnement côtier, (2) l’étude des maladies affectant les...
Tipo: Text
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00319/43055/42562.pdf

Plankton community composition in relation to availability and uptake of oxidized and reduced nitrogen
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Berg, Gm; Balode, M; Purina, I; Bekere, S; Bechemin, Christian; Maestrini, Serge.
Trends in nitrogen utilization, determined with N-15-labeled substrates, were related to blooms of distinct phytoplankton groups in the Gulf of Riga, Baltic Sea, during May, June and July 1999. The dominant phytoplankton groups included diatoms, cryptophytes, dinoflagellates, and filamentous cyanobacteria. As the water column became progressively more stratified over the growing season, diatoms comprised a smaller proportion of the total phytoplankton assemblage and almost disappeared by late summer. Their disappearance correlated with undetectable surface-water nitrate concentrations and low nitrate uptake rates (5 to 8% of total nitrogen uptake). Diatoms were the only phytoplankton group significantly associated with the uptake of oxidized nitrogen...
Tipo: Text
Palavras-chave: Nitrogen uptake; DON; Nitrate; Diatoms; Cyanobacteria; Cryptophytes; Baltic Sea; Gulf of Riga.
Ano: 2003
URL: http://archimer.ifremer.fr/doc/00000/10207/7595.pdf

Suivi « hydrologie » et « phytoplancton » des masses d'eau du bassin hydrographique Adour-Garonne sur la période 2010-2015
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Auby, Isabelle; D'Amico, Florence; Meteigner, Claire; Ganthy, Florian; Maurer, Daniele; Gouriou, Laure; Rigouin, Loic; Rumebe, Myriam; Tournaire, Marie-pierre; Trut, Gilles; Oger-jeanneret, Helene; Guesdon, Stephane; Derrien, Annick; Chabirand, Jean-michel; Genauzeau, Sylvie; Schmitt, Anne; Geairon, Philippe; Grizon, James; Seugnet, Jean-luc; Thomas, Gerard; Bechemin, Christian; Soudant, Dominique; Lamoureux, Alice; Beaugrand, Philippe; Noureau, Bruno; Michel, Valérie; Dupin, Michel; Bariou, Jean; Landier, Pascal; Miguel, Véronique.
Tipo: Text
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00355/46583/46391.pdf