Consulta: creatorFacets:"David, Valerie"
Registros recuperados: 6
Data/hora: 01/06/2024 01:24:39

The paradox between the long-term decrease of egg mass size of the calanoid copepod Eurytemora affinis and its long-term constant abundance in a highly turbid estuary (Gironde estuary, France)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: David, Valerie; Sautour, Benoit; Chardy, Pierre.
Eurytemora affinis egg mass size-a commonly used demographic parameter-was surveyed in the Gironde estuary. Its decrease between 1978 and 2003 contrasted with the stability of population density during this long-term period. Different hypotheses were tested to explain this paradox. (i) Upstream shift of the population: Even though the population of E. affinis shifted upstream due to a greater penetration of marine water, no relationship between the population shift and demographic parameters was observed: the egg mass size exhibited the same evolution upstream. (ii) Water warming: No early egg production and no change of female size that could metabolically limit the egg mass size was observed. (iii) Food limitation: The change in food quality observed did...
Tipo: Text
Ano: 2007
URL: https://archimer.ifremer.fr/doc/00470/58194/60699.pdf

Spatial and long-term changes in the functional and structural phytoplankton communities along the French Atlantic coast
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: David, Valerie; Ryckaert, Mireille; Karpytchev, Mikhail; Bacher, Cedric; Arnaudeau, Vanessa; Vidal, Nadia; Maurer, Daniele; Niquil, Nathalie.
Spatial and interannual variations of phytoplankton diversity were characterized along the French Atlantic Coast in relation to physical factors and large-scale climatic indices using phytoplankton surveys conducted from 1993 to 2010 in four geographical areas. This study relates phytoplankton diversity to oyster recruitment success by comparing a 'specific' versus a 'functional' diversity approach. Functional diversity was represented by functional groups of different phytoplanktonic functional traits (size, shape, toxicity), relevant for oyster feeding during growth, reproduction and larval development. Phytoplankton diversity patterns along the French Atlantic coast corresponded to a geographical distribution mainly driven by a latitudinal gradient and...
Tipo: Text
Palavras-chave: Phytoplankton; Long-term variation; Spatial variation; Climate; Atlantic coast.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00093/20376/19677.pdf

Dynamics of particulate organic matter composition in coastal systems: a spatio-temporal study at multi-systems scale
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Lienart, Camilla; Savoye, Nicolas; Bozec, Yann; Breton, Elsa; Conan, Pascal; David, Valerie; Feunteun, Eric; Grangere, Karine; Kerherve, Philippe; Lebreton, Benoit; Lefebvre, Sebastien; L'Helguen, Stephane; Mousseau, Laure; Raimbault, Patrick; Richard, Pierre; Riera, Pascal; Sauriau, Pierre-guy; Schaal, Gauthier; Aubert, Fabien; Aubin, Sebastien; Bichon, Sabrina; Boinet, Christophe; Bourasseau, Line; Breret, Martine; Caparros, Jocelyne; Cariou, Thierry; Charlier, Karine; Claquin, Pascal; Cornille, Vincent; Corre, Anne-marie; Costes, Laurence; Crispi, Olivier; Crouvoisier, Muriel; Czamanski, Marie; Del Amo, Yolanda; Derriennic, Herve; Dindinaud, Francois; Durozieri, Maia; Hanquiez, Vincent; Nowaczyk, Antoine; Devesa, Jeremy; Ferreira, Sophie; Fornier, Michel; Garcia, Fabrice; Garcia, Nicole; Geslin, Sandrine; Grossteffan, Emilie; Gueux, Aurore; Guillaudeau, Julien; Guillou, Gael; Joly, Orianne; Lachaussee, Nicolas; Lafont, Michel; Lamoureux, Jezabel; Lecuyer, Eric; Lehodey, Jean-paul; Lemeille, David; Leroux, Cedric; Mace, Eric; Maria, Eric; Pineau, Philippe; Petit, Franck; Pujo-pay, Mireille; Rimelin-maury, Peggy; Sultan, Emmanuelle.
In coastal systems, the multiplicity of sources fueling the pool of particulate organic matter (POM) leads to divergent estimations of POM composition. Eleven systems (two littoral systems, eight embayments and semi-enclosed systems and one estuary) distributed along the three maritime façades of France were studied for two to eight years in order to quantify the relative contribution of organic matter sources to the surface-water POM pool in coastal systems. This study was based on carbon and nitrogen elemental and isotopic ratios, used for running mixing models.  The POM of the estuary is dominated by terrestrial material (93% on average), whereas the POM of the other systems is dominated by phytoplankton (84% on average). Nevertheless, for the latter...
Tipo: Text
Palavras-chave: Particulate organic matter; Coastal systems; C and N stable isotopes; C:N ratio; Mixing model.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00374/48550/48871.pdf

Dynamics of particulate organic matter composition in coastal systems: forcing of spatio-temporal variability at multi-systems scale
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Lienart, Camilla; Savoye, Nicolas; David, Valerie; Ramond, Pierre; Tress, Paco Rodriguez; Hanquiez, Vincent; Marieu, Vincent; Aubert, Fabien; Aubin, Sebastien; Bichon, Sabrina; Boinet, Christophe; Bourasseau, Line; Bozec, Yann; Breret, Martine; Breton, Elsa; Caparros, Jocelyne; Cariou, Thierry; Claquin, Pascal; Conan, Pascal; Corre, Anne-marie; Costes, Laurence; Crouvoisier, Muriel; Del Amo, Yolanda; Derriennic, Herve; Dindinaud, Francois; Duran, Robert; Durozier, Maia; Devesa, Jeremy; Ferreira, Sophie; Feunteun, Eric; Garcia, Nicole; Geslin, Sandrine; Grossteffan, Emilie; Gueux, Aurore; Guillaudeau, Julien; Guillou, Gael; Jolly, Orianne; Lachaussee, Nicolas; Lafont, Michel; Lagadec, Veronique; Lamoureux, Jezabel; Lauga, Beatrice; Lebreton, Benoit; Lecuyer, Eric; Lehodey, Jean-paul; Leroux, Cedric; L'Helguen, Stephane; Mace, Eric; Maria, Eric; Mousseau, Laure; Nowaczyk, Antoine; Pineau, Philippe; Petit, Franck; Pujo-pay, Mireille; Raimbault, Patrick; Rimmelin-maury, Peggy; Rouaud, Vanessa; Sauriau, Pierre-guy; Sultan, Emmanuelle; Susperregui, Nicolas.
In costal systems, particulate organic matter (POM) results from a multiplicity of sources having their respective dynamics in terms of production, decomposition, transport and burial. The POM pool experiences thus considerable spatial and temporal variability. In order to better understand this variability, the present study employs statistical multivariate analyses to investigate links between POM composition and environmental forcings for a panel of twelve coastal systems distributed along the three maritime regions of France and monitored weekly to monthly for 1 to 8 years. At multi-system scale, two main gradients of POC composition have been identified: a ‘Continent-Ocean’ gradient associated with hydrodynamics, sedimentary dynamics and depth of the...
Tipo: Text
Palavras-chave: Particulate organic matter; Coastal systems; Environmental forcing; Meta-analysis; France.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00433/54471/55848.pdf

Spatial patterns in the condition index of the wild Pacific oyster Crassostrea gigas in a macrotidal coastal ecosystem: Influence of tidal processes and beyond
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Gasmi, Sonia; Bernard, Ismael; Pouvreau, Stephane; Maurer, Daniele; Schaal, Gauthier; Ganthy, Florian; Cominassi, Louise; Allain, Gwenhael; Sautour, Benoit; David, Valerie.
In macrotidal coastal ecosystems, spatial heterogeneity of the water column properties is induced by both oceanic and continental influences. Hydrodynamic processes generate a land-sea gradient of environmental conditions, affecting the biological performances of sedentary organisms. The aim of the present study is to establish an extensive spatial assessment in the reproductive investment of the wild Pacific oyster Crassostrea gigas in Arcachon Bay. This is done by looking for a relationship between the Lawrence and Scott condition index (LSCI) and two tidal processes: the immersion level (IL) and the local oceanic flushing time (LoFt). The LSCI of C. gigas was assessed, just before gamete release, at 68 sampling stations in Arcachon Bay. Oyster...
Tipo: Text
Palavras-chave: Reproductive investment; Crassostrea gigas; Macrotidal lagoon; Immersion level; Oceanic flushing; Environmental variability.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00357/46803/46670.pdf

Influence of phytoplankton diversity and community structure on oyster reproduction (Arcachon Bay, France)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Gonzales, Arriagada; Bernard, Ismael; Maurer, Daniele; Auby, Isabelle; Gasmi, Sonia; Pouvreau, Stephane; David, Valerie.
Arcachon Bay is one of the most important spat-supplying area for the French oyster production. During the last 16 years, the local economic activity of spat production has been threatened recurrently by a high interannual variability of seed harvesting. This threatened spat production was attributed to reproductive problems highlighted by both a delay in oyster spawning and a decrease of small larvae abundances since 1995. Recent works showed that these two reproduction indices seem closely related to climate change that might controls the phytoplankton communities of the Bay. Food availability in term of quantity and quality appears thus as a serious track to understand the reproductive problems of oyster in the Arcachon Bay. The aim of this work was...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00257/36828/35454.pdf