Occurrence of priority and emerging organic compounds in fishes from the Rhone River (France)
The main objective of this study was to collect new data on the occurrence and levels of priority and emerging organic compounds in freshwater fishes sampled in the Rhone River. The 34 studied contaminants included alkylphenols (AP), bisphenol A (BPA), polybromodiphenylethers (PBDE), perfluorinated compounds (PFC), hexabromocyclododecanes (HBCD), hexachloro-benzene (HCB) and hexachloro-butadiene (HCBD). About 50 fish samples (individual specimens or pooled fishes) were collected from 3 sites located upstream and downstream of the Lyon metropolitan area in the Rhone River (France). Four species were caught at each site, namely: the barbel (Barbus barbus), the common bream (Abramis brama), the white bream (Blicca bjoerkna) and the chub (Squalius cephalus). Some contaminants were quantified in all the 32 fish samples analysed: 4-nonylphenol, Α-HBCD, the 6 PBDE congeners (28, 47, 99, 100, 153, 154), perfluorooctanesulfonate (PFOS) and perfluorodecanoic acid. And 23 of the 32 samples had concentration of PFOS above the Environmental Quality Standards (up to 6 times higher the EQS); and all the 32 samples had concentrations of PBDE above the EQS (up to 4000 times higher, with the sum of 6 PBDE varying from 4.5 to 182 ng/g dw). Clearly, the interest to consider PFOS and HBCD as new priority substances is confirmed. In contrast, the pertinence of a priority status for HCBD, which was never quantified in our study, might have to be reconsidered in the future.
(Analytical and Bioanalytical Chemistry. vol. 404, n° 1618-2642, pp. p. 2721 - p. 2735, 12/04/2026)
UR MALY, IRSTEA, SISYPHE, UPMC, EPHE, PSL, PSL, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LABERCA, INRA, ONIRIS, IFREMER, EHF, UCBL, CNRS
Distribution of Dinophysis species in the Bay of Biscay and possible transport pathways to Arcachon Bay
Dinophysis is the most harmful toxic phytoplankton on the French coast in terms of its impact on local economy and public health. In Arcachon Bay, Dinophysis spp. have periodically affected shellfish industry for the last ten years; the most important events are analysed in detail in this paper. Regular monitoring revealed that these events originated outside Arcachon Bay in the open ocean. Data from 14 surveys and two coastal networks showed that Dinophysis was primarily found in the vicinity of Capbreton, 100 km south of the mouth of Arcachon Bay. The Dinophysis distribution on the continental shelfwas determined during two surveys in 2005 and 2008: the highest concentrationswere located along the coast and reached 18000 cells.L−1. Analysis of available current data revealed that strong westerlies lead to northward currents of up to 19 cm.s−1. These marinemeteorological conditionswere frequently observed just prior to Dinophysis events and lead us to suggest that northward currents transport Dinophysis from the Capbreton area to Arcachon Bay.
(Journal of Marine Systems, n° 0924-7963, 21/12/2011)
IFREMER, PFOM, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, DYNECO, IFREMER, LIENSs, INSU - CNRS, ULR, CNRS
Seagrass colonization: Knock-on effects on zoobenthic community, populations and individual health
This study provided evidence that Zostera noltii presence affects macrofauna community structure independently from median sediment grain-size and that the notion of ecosystem health is rather subjective: in the present case, we recorded “good health” in terms of seagrass development, “no impact” in terms of macrobenthic biotic indices and “negative effect” for a given key-population. The occurrence and development of a Z. noltii seagrass bed was surveyed at Banc d’Arguin, Arcachon Bay (France), to estimate the modification of the macrozoobenthic community and of the dynamics of a key-population for the local ecosystem, – the cockle Cerastoderma edule. Even though median grain-size of the sediment decreased only at the very end of the survey, i.e. when seagrass totally invaded the area, most of the macrofauna community characteristics (such as abundance and biomass) increased as soon as Z. noltii patches appeared. The structure of the macrofauna community also immediately diverged between sand and seagrass habitats, without however modifying the tested biotic indices (BENTIX, BOPA, AMBI). The health of the cockle population (growth, abundance, recruitment) was impacted by seagrass development. Related parasite communities slowly diverged between habitats, with more parasites in the cockles from seagrass areas. However, the number of parasites per cockle was always insufficient to alter cockle fitness.
(Estuarine, Coastal and Shelf Science. vol. 95, n° 0272-7714, pp. 458-469, 20/12/2011)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Hydrodynamic processes, velocity structure and stratification in natural turbidity currents: Results inferred from field data in the Var Turbidite System
The Var Turbidite System (NW Mediterranean Sea) is fed during the present-day highstand sea level by large earthquake-induced ignitive turbidity currents, low-density turbidity currents resulting from retrogressive failures triggered on the upper continental slope, and hyperpycnal flows related to the Var River floods. Using a large dataset including bathymetric data, side-scan sonar images, seismic-reflection profiles, cores and photographs of the seafloor, this paper attempts to better constrain the hydrodynamic behaviour of debris flows and turbidity currents along the Upper and Middle Valley of the Var Turbidite System. The drastic change of the seafloor morphology between the Upper and the Middle Valley suggests that gravity flows undergo rapid transformation from cohesive to fully turbulent behaviour. This transformation is related to a hydraulic jump caused by an abrupt decrease in slope angle at the transition between the Upper and the Middle Valley and is associated with en masse deposition and elevation of the seafloor. Strong seafloor erosion prevails in the Middle Valley, suggesting that, for a low and constant slope angle, turbulent flows must regain a balance between concentration and flow thickness rapidly after they experience hydraulic jump. The internal stratification and vertical grain-size distribution within turbulent flows are inferred from the distribution of fine- to coarse-grained turbidites found in cores located along the crest of the Var Sedimentary Ridge with a decreasing elevation above the floor of the Middle Valley. The theoretical vertical velocity profile deduced from the vertical grain-size distribution exhibits a general trend and an inflection of the gradient curve different from those of the velocity profiles classically obtained using numerical modelling.
(Sedimentary Geology. vol. 245-246, n° 0037-0738, pp. 48-62, 16/12/2011)
GEOAZUR 6526, IRD, UPMC, UNS, INSU - CNRS, UniCA, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GM, IFREMER
Végétation et climat de la Patagonie chilienne au cours des derniers 20 000 ans d’après les données polliniques marines
Dans le contexte du réchauffement climatique, les enregistrements paléoclimatiques à différentes échelles temporelles et spatiales apparaissent essentiels pour comprendre les mécanismes du climat. La Patagonie Chilienne (41°S à 56°S) parcourue du Nord au Sud par les Andes représente une contrainte topographique majeure sur les circulations atmosphériques et océaniques. Cette région est la seule qui intercepte la totalité de la ceinture des vents d'ouest austraux et constitue donc une zone clé pour étudier les changements paléoenvironnementaux et comprendre les mécanismes océan-atmosphère et leurs interactions aux moyennes et hautes latitudes de l'hémisphère sud. Dans ce contexte, les objectifs de cette thèse sont : (1) de tester l’analyse pollinique dans les sédiments marins de cette région, (2) d’étudier les modifications des paléoenvironnements continentaux au cours des 20 000 dernières années à partir de deux carottes océaniques de la campagne "PACHIDERME" (MD07-3088 et MD07-3104) et (3) de déterminer leurs liens avec l’activité des vents d’ouest et avec l’influence de ces vents dans l’hémisphère sud et donc sur le climat à l’échelle globale. Les analyses polliniques dans les sédiments marins de surface à l’intérieur et à l’extérieur des fjords de la Patagonie reflètent fidèlement la végétation actuelle développée sur le continent le plus proche, ce qui prouve la validité de la palynologie marine dans cette région. Au niveau de la péninsule de Taitao (46°S), l’expansion des forêts nord patagoniennes après 17.6 ka marque le début de la déglaciation. Cette dernière est interrompue par un évènement froid et humide, l’Antarctic Cold Reversal (ACR) qui s’exprime ici par le développement des tourbières de Magellan et est lié à l’intensification des vents d’ouest. Le développement de taxons héliophiles à ~11 ka illustre le début de l’Holocène sous des conditions plus chaudes et plus sèches qui sont également enregistrées autour du Fjord de Reloncavi (41°S). Ces conditions persistent jusqu’à ~8-7 ka, puis les changements de végétation aux cours de l’Holocène montrent une variabilité climatique plus importante évoluant vers un climat plus froid et plus humide qui se renforce au nord de la Patagonie après ~6-5 ka puis pendant l’Holocène supérieur. La comparaison de nos résultats avec les données paléoclimatiques de la région souligne les déplacements de la ceinture des vents d’ouest. Après une descente rapide vers le sud au début de la déglaciation, cette ceinture des vents d’ouest remonte vers le nord pendant l’ACR avant de redescendre à nouveau vers le sud à l’Holocène proche de sa position actuelle. Ce phénomène appuie l’hypothèse d’un lien entre les variations du CO2 atmosphérique et la ceinture des vents d’ouest jusqu’au début de l’Holocène. A partir de l’Holocène moyen et supérieur, la ceinture des vents d’ouest s’élargit avec un léger retour vers le nord probablement lié à la mise en place d’El Niño au niveau de l’océan Pacifique tropical.
(12/12/2011)
LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA
Développement des méthodes analytiques pour la détection et la quantification de traces des HAP et de pesticides dans l'eau. Application à l'évaluation de la qualité des eaux libanaises.
La pollution des eaux est particulièrement problématique pour les pays industrialisés et les pays en développement. Des suivis environnementaux se sont alors avérés nécessaires afin de progresser dans la compréhension des origines et des conséquences de la présence de ces polluants. Parmi les polluants organiques les plus dangereux, les Hydrocarbures Aromatiques Polycycliques (HAP) et les pesticides qui peuvent se retrouver à l'état de traces dans les milieux aquatiques. Leur analyse nécessite des méthodes analytiques à la fois spécifiques et sensibles. L'Extraction sur Phase Solide (SPE) suivi d'une analyse par la Chromatographie Gazeuse couplée à la Spectrométrie de Masse (GC-MS) est la méthode la plus couramment employée. Les travaux de thèse s'inscrivent ainsi dans l'optique générale visant à développer des nouvelles méthodes analytiques pour l'extraction et l'analyse de ces deux familles de polluants organiques présents dans l'eau. Afin de pallier les contraintes classiques de la SPE, une nouvelle approche a été développée qui consiste à introduire la technique de centrifugation dans certaines étapes de la procédure SPE. La nouvelle méthode élaborée a permis de réduire considérablement le temps de préparation et d'économiser l'utilisation et le rejet des solvants organiques, en réduisant presque 10 fois les volumes nécessaires à l'obtention des rendements de récupération satisfaisants. Une méthode d'analyse par injection à température programmable (PTV) a été optimisée afin d'améliorer les seuils de détection des HAP. Cette étude a permis également d'avoir les informations sur la qualité des eaux de pluie, eaux souterraines et eaux de surface au Liban quant au niveau de leur contamination pour les HAP et les pesticides.
(08/12/2011)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CNRS-L
Evidence for oceanic oxygen depletion in the face of cooling in the early Pleistocene
Future climate change is predicted to significantly impact ocean circulation and, potentially, to reduce ocean oxygenation. Paradoxically, the transition from the warm Pliocene, often held as an analog for a future, warmer Earth, to the cool Pleistocene appears to accompany a decrease in intermediate water oxygenation. The Plio-Pleistocene cooling begins with the onset of major Northern Hemisphere glaciation, around 3.0-2.7 million years ago (Ma). High latitude cooling and extension of the polar ice caps led to cooling of the deep ocean and shoaling of the thermocline. The transition culminated in the cooling of the whole surface ocean and establishment of strong zonal and meridional atmospheric circulation from 2.0 Ma. A compilation of high-resolution nitrogen isotope records from the eastern equatorial Pacific, North Pacific, and the Arabian Sea and a global multi-site survey, indicates that regional intensification of oxygen minimum zones (OMZs) and expansion of water column denitrification accompanied the cooling and circulation changes at ~2.0 Ma. Large-scale open ocean suboxia intensified with the inception of a modern polar frontal system, despite lower temperatures and thus higher initial oxygen contents of the mode waters themselves. This likely reflects the increased importance of aged mode waters as the principle conduit of nutrients and oxygen to the OMZs. These results stress how climate-related changes in circulation may complicate our ability to predict ocean biogeochemical changes on a changing Earth.
(. vol. 41, pp. 0214, 01/12/2011)
URI, PALEOPROXUS, LOCEAN, IPSL, ENS-PSL, UVSQ, UPMC, CEA, INSU - CNRS, X, CNES, CNRS, MNHN, IRD, UPMC, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CAU
Impact of toxicant exposure on the proteomic response to intertidal condition in Mytilus edulis
Intertidal blue mussels display physiological adaptations to emersion-submersion cycle that can be impacted by response to chemicals. In order to study the interference of cellular response to pollutants on intertidal physiology, we analysed proteomic (2-DE) responses in gills of mussels exposed for 14 days to regular emersion (intertidal condition) or continuous submersion (subtidal condition) and to a mixture (B[a]P/ phenantrene) of polycyclic aromatic hydrocarbons (PAHs). Antioxidant activities were measured as general stress markers. In clean context, emersion generated several over-expressions of proteins mainly involved in cytoskeleton, chaperoning, energetic metabolism and transcription regulation. Mussels exposed to PAHs showed equivalent accumulation levels of contaminants in both physiological conditions but an increased GST activity specifically in intertidal context, highlighting the high degree of stress underwent in this group, as well as over-expressions of Cu/Zn SOD and stress proteins in subtidal context. Presence of contaminants partly impacted the response to emersion: cytoskeletal rearrangements and energetic adjustments were mostly maintained whereas stress response was dramatically altered. These findings highlight the potential adverse effects of toxicants on physiological adjustments linked to air-exposure, thus suggesting to take into account in the evaluation of environmental risk the multiplicity of stresses that wild animals are likely to encounter.
(Comparative Biochemistry and Physiology - Part D: Genomics and Proteomics. vol. 6, n° 1744-117X, pp. 357-369, 01/12/2011)
SEBIO, INERIS, URCA, ULH, NU, URCA, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UNIROUEN, NU, INSERM, DC2N, UNIROUEN, NU, INSERM
High-latitude obliquity as a dominant forcing in the Agulhas current system
The Agulhas Current transport of heat and salt from the Indian Ocean into the South Atlantic around South Africa (Agulhas leakage), can affect the Atlantic meridional overturning circulation (AMOC) and, thus, influence global climate. However, efforts to elucidate forcing mechanisms connecting the Agulhas leakage with the upstream dynamics of the current have been hampered by a lack of climate records extracted from the area where the Agulhas current originates. We determine 800-kyr sea surface temperature (SST) and salinity (SSS) records from the "precursor" region of the Agulhas current and show that these records contain strong 100-kyr and 41-kyr cycles. This latter obliquitydriven cycle is nearly in phase with changes in the annual mean insolation and air temperature at high southern latitudes. In contrast, our SST and SSS records did not reveal precession-driven cycles, which is surprising given the lowlatitude location of the upstream Agulhas current. Together, this indicates that the dynamics of the Agulhas current system is mainly controlled by high latitude obliquity through its influence on the position of the Southern Hemisphere subtropical front (STF) and its associated westerlies. Our study demonstrates that obliquity may drive an important part of the 100 kyr cycles observed in the system rather than precession. Our results also suggest that a stronger Agulhas current, associated with a northward shift of the wind system dur-
(Climate of the Past. vol. 7, n° 1814-9324, pp. 1285 - 1296, 26/11/2011)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LSCE, CEA, CNRS
Impacts of habitat contamination on the health of declining American and European eel populations
This research project is a joint initiative of researchers from Québec and France. Its general objective is to examine the relationships between pollution, both inorganic and organic, and the health of Atlantic eels in the Gironde and the St Lawrence estuaries.
(pp. 1, 13/11/2011)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IRSTEA, UR EPBX, CEMAGREF