12 research outputs found
Projet OSCREEN / Volet 2 : influence des paramĂštres environnementaux sur le stock dâOstreopsis sp. macroalgal. Campagne Ă©tĂ© 2011.
AprĂšs avoir traitĂ© dans son volet 1 de la rĂ©partition gĂ©ographique du stock dâOstreopsis macroalgal, en rĂ©gion PACA, en Languedoc-Roussillon et en Corse, le projet OSCREEN a pour objectif dans son volet 2 de caractĂ©riser Ă partir de donnĂ©es spatialisĂ©es issues de modĂšles et dâimagerie satellitaire les conditions environnementales dâapparition des blooms de lâOstreopsis macroalgal, afin de venir en appui Ă lâoptimisation de rĂ©seaux dâalerte. La variabilitĂ© et les interfĂ©rences multifactorielles empĂȘchent de dĂ©crire des scĂ©narii gĂ©nĂ©ralisables entre sites. Mais lâapproche spatiale a permis de mettre en Ă©vidence le lien potentiel entre lâimportance des blooms et les dessalures dâun site. Le travail suggĂšre des pistes de recherches Ă dĂ©velopper.After determining, in its part 1, the geographical distribution of the macroalgal stock of Ostreopsis in the PACA region, Languedoc-Roussillon and Corsica, the OSCREEN project has for objective in its part 2 to characterize from spatial data producted by models and by satellite imagery the environmental conditions of appearance of the blooms of macroalgal Ostreopsis, to abut to the optimization of warning systems. Variability and multifactorial interferences prevent to describe generalized scenarios between sites. But the spatial approach has highlighted the potential link between the size of blooms and declines in salinity for a site. The work suggests paths for research to develop
Optimisation de la surveillance des masses dâeau DCE en MĂ©diterranĂ©e. Utilisation de produits dĂ©rivĂ©s dâimages satellites en complĂ©ment du rĂ©seau de mesures in-situ
This study aims at showing the potential of « water colour » data derived from satellite imagery to optimise the monitoring of coastal waters within the WFD, with the French Mediterranean as a study area. The work is focused on one specific parameter, the surface chlorophyll-A (chl-a) concentration of which a monthly atlas for reference to ânormalâ values is provided, which consists of : (i) the monthly chl-a median computed from satellite data of 2003, 2004 and 2005 ; (ii) the integration in space of these values, represented by their average over the WFD water masses (except those of very small size) ; (iii) an indicator of the spatial variability of the chl-a through the spatial standard deviation within each water mass. Another important result is the characterisation of the ecological status of the WFD water masses by the 90th Percentile of the Chl-a concentration compared to a « good status threshold » as defined for the WFD for the Mediterranean. The study highlights the complementarity between in situ measured data, very local but precise and exhaustive, and the parameters accessible through satellite imagery that provide total coverage and allow to perform spatial analysis, and therefore to consider the notion of heterogeneity within water masses. This last aspect can have important implications in evaluating how the water masses were designed and in assessing the placement of the measuring points for a good representativity of the entire water massLâĂ©tude « optimisation » a pour but de montrer le potentiel des donnĂ©es « couleur de lâeau » dĂ©rivĂ©es dâimagerie satellitaire pour optimiser la surveillance des eaux cĂŽtiĂšres dans le cadre de la DCE, avec pour zone dâĂ©tude la MĂ©diterranĂ©e française. Le travail est concentrĂ© sur un paramĂštre en particulier, la concentration de surface en chlorophylle-A (chl-a) dont on fournit un atlas mensuel pour rĂ©fĂ©rence Ă des valeurs normales et constituĂ© de (i) la mĂ©diane mensuelle de la chl-a calculĂ©e sur des donnĂ©es satellites de 2003, 2004 et 2005 ; (ii) lâintĂ©gration dans lâespace de ces valeurs, concrĂ©tisĂ©e par leur moyenne pour chaque masse dâeau DCE (sauf celles de trĂšs petite taille) ; (iii) un indicateur de la variabilitĂ© spatiale de la chl-a au travers de lâĂ©cart type spatial au sein de chaque masse dâeau. Un autre rĂ©sultat important est la caractĂ©risation de lâĂ©tat Ă©cologique des masses dâeau DCE par le Percentile 90 de la concentration Chl-a comparĂ©e au « seuil de bon Ă©tat » dĂ©fini pour la DCE sur la MĂ©diterranĂ©e. LâĂ©tude fait ressortir la complĂ©mentaritĂ© entre donnĂ©es de mesures in situ, ponctuelles mais prĂ©cises et exhaustives, et les paramĂštres accessibles par satellite qui offrent une couverture totale et permettent lâaccĂšs Ă une analyse spatiale, donc Ă une notion dâhĂ©tĂ©rogĂ©nĂ©itĂ© au sein des masses dâeau. Ce dernier aspect peut avoir des implications importantes lâĂ©valuation du dĂ©coupage des masses dâeau et dans le bon placement des points de mesure pour une bonne reprĂ©sentation de lâensemble dâune masse dâeau
Vérification des conditions de référence des eaux cÎtiÚres de Corse. Utilisation de la plate-forme de modélisation
This report comes within convention #2007 1742 between the Water Agency for RhĂŽne, the Mediterranean and Corsica (AERM&C) and Ifremer, with the title âVerification of the reference conditions for coastal water in Corsica â Use of the modelling platformâ. It consisted of an application for Corsica of the development implemented by Ifremer within the Mediterranean coastal modelling platform. This implements the MARS-3D hydrodynamic model of Ifremer on the Mediterranean which allows to simulate currents, height of water column, salinity and temperature. The model is operational and provides data accessible to the public on the MENOR zone (North west Mediterranean) with a 1,2 km resolution. These data were utilised to provide a hydrodynamic characterisation of the Corsican coastal water masses as defined for the European Water Framework Directive. They were the base for the computation of yearly and monthly water renewal rates in the water masses for the year 2006, considered as a reference year, thus giving an indication of their sensitivity to a possible contamination. These results are presented in cartographic format in a simplified reference atlas. Model outputs on the MENOR window have also started, in preliminary tests, to be utilised as data of initial conditions and conditions to the limits to implement the model over a Corsica window with a finer resolution of 400 meters that is expected to improve the precision of the representation of the coastal hydrodynamic processes.Ce rapport sâinscrit dans le cadre de la convention N° 2007 1742 entre lâAgence de lâEau RhĂŽne MĂ©diterranĂ©e et Corse (AERM&C) et lâIfremer, intitulĂ©e « VĂ©rification des conditions de rĂ©fĂ©rence des eaux cĂŽtiĂšres Corse â Utilisation de la plate-forme de modĂ©lisation ». Elle consiste en une application concernant la Corse des dĂ©veloppement rĂ©alisĂ©s par lâIfremer dans le cadre de la plateforme de modĂ©lisation des courants cĂŽtiers en mĂ©diterranĂ©e. Celle-ci utilise le code de calcul MARS-3D de lâIfremer sur la MĂ©diterranĂ©e qui permet de simuler les courants, la hauteur dâeau, la salinitĂ© et la tempĂ©rature. Le modĂšle est opĂ©rationnel et fournit des donnĂ©es accessibles au public sur la Zone MENOR (mĂ©diterranĂ©e Nord-Ouest), Ă 1,2 km de rĂ©solution. Ces donnĂ©es ont Ă©tĂ© utilisĂ©es pour fournir une caractĂ©risation hydrodynamique de masses dâeau corses dĂ©finies pour la Directive EuropĂ©enne Cadre sur lâEau. Elles ont fourni la base pour le calcul des temps de renouvellement annuel et mensuel des masses dâeau pour lâannĂ©e 2006, considĂ©rĂ©e comme une annĂ©e type, donnant ainsi une indication de leur sensibilitĂ© Ă une contamination Ă©ventuelle. Ces rĂ©sultats sont prĂ©sentĂ©s sous forme cartographique dans un atlas de rĂ©fĂ©rence simplifiĂ©. Les sorties du modĂšle sur lâemprise MENOR ont en outre Ă©tĂ© utilisĂ©es comme donnĂ©es de conditions initiales et conditions aux limites pour effectuer des simulations sur une fenĂȘtre CORSE, avec une maille plus fine de 400 m qui devrait permettre, Ă moyen terme, dâaffiner les rĂ©sultats et reflĂ©ter plus prĂ©cisĂ©ment les phĂ©nomĂšnes hydrodynamiques cĂŽtiers
Suivi de la vĂ©gĂ©tation en zone sĂšche par des produits dâinformation dĂ©rivĂ©s de lâimagerie spatiale
peer reviewe
Ostreopsis cf. ovata in the French Mediterranean coast: molecular characterisation and toxin profile
The presence of dinoflagellates of the genus Ostreopsis along Mediterranean coasts was first observed in 1972, in the bay of Villefranche-sur-Mer. However, over the past ten years, harmful events related to this benthic dinoflagellate have been reported in Italian, Spanish, Greek, French, Tunisian and Algerian coastal areas. In France, during a hot period in August 2006, cases of dermatitis and respiratory problems were registered in Marseille area. At that time, a link to the proliferation of Ostreopsis was highlighted for the first time in that area. A specific monitoring was designed and implemented in the summer 2007. Two strains of Ostreopsis cf. ovata, collected in 2008 from Villefranche-sur-Mer and Morgiret coastal waters and grown in culture, were identified by molecular analysis and studied to characterise their growth and toxin profile. Liquid chromatography-mass spectrometry (LC-MS/MS) indicated that both strains produced ovatoxin-a (OVTX-a) as the major component (ca. 90%), and traces of palytoxin (PLTX). Toxin content was determined at the end of the exponential growth phase with highest concentration of 55 pg.cell(-1) of OVTX-a and 2.5 pg.cell(-1) of PLTX
Le Référentiel Benthique Méditerranéen (REBENT MED)
The Mediterranean benthic network proposes an integrated approach in term of scientific research and monitoring networks dealing with benthic biocenosis in the Mediterranean Sea (French part) ; it gives a state of the art as well as future needs, regarding regulatory aspects and data storage.Lâavant projet sommaire du REBENT MĂ©diterranĂ©e propose une approche intĂ©grĂ©e des recherches et surveillances portant sur les biocĂ©noses benthiques en MĂ©diterranĂ©e ; il dresse un Ă©tat de lâart des connaissances en la matiĂšre ainsi que des besoins futurs, en ciblant sur lâĂ©coute de la demande sociĂ©tale et des cadres de gestion, ainsi que la bancarisation des donnĂ©e