Trematode communities in cockles (Cerastoderma edule) of the Ria de Aveiro (Portugal): Influence of inorganic contamination
This work aims to assess the trematode parasites infecting the edible cockle Cerastoderma edule, collected in the Ria de Aveiro lagoon, one of the most relevant biodiversity hotspots of the Western Iberia, and evaluate the relationship between the observed patterns and environmental descriptors. A total of 11 of the 16 trematode species known to infect C. edule were identified, including Himasthla continua and Psilostomum brevicolle as new occurrences in this lagoon. Parvatrema minutum was the most abundant and dominant species. Species richness and prevalence were high. The relationship between trematode species abundance, intensity and prevalence, and also environmental variables, showed that most parasites preferred muddy sand areas with euhaline conditions in opposition to areas with contamination and/or distant from the lagoon entrance. This study highlighted the good ecological status of the ecosystem and the transitional biogeographic characteristics of the western Portuguese coast where northern and subtropical faunas can coexist.
(Marine Pollution Bulletin. vol. 82, n° 0025-326X, pp. 117-126, 27/03/2014)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Sandra E. Shumway (Ed.) : Shellfish aquaculture and the environment
(Environmental Science and Pollution Research, n° 0944-1344, 26/03/2014)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
PCB Integration of a Vivaldi Antenna on IPD Technology for 60-GHz Communications
The integration of a Vivaldi antenna on a printed circuit board (PCB) targeting 60-GHz WiGig applications is presented in this letter. The integrated passive device (IPD)technology from STMicroelectronics based on a glass substrate is used for the antenna manufacturing. In free space, the radiation pattern measurements show a realized gain higher than 4 dBi in the endfire direction from 56 to 65 GHz. The impact of the integration of the antenna on the PCB is investigated in details showing reasonable disturbance of the reflection coefficient, but strong modifications of the radiation pattern, especially the pointing direction of the main beam. From the analysis of the surface waves propagating along the PCB when the Vivaldi is integrated, a novel topology is proposed to preserve the main radiation in the endfire direction with enhanced realized gain.
(IEEE Antennas and Wireless Propagation Letters. vol. 13, n° 1536-1225, pp. 678-681, 16/03/2014)
ST-CROLLES, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEAT, UNS, CNRS, UniCA
What are the outcomes of an industrial remediation on a metal-impacted hydrosystem? A 2-year field biomonitoring of the filter-feeding bivalve Corbicula fluminea
The Riou-Mort watershed (southwest France) exhibits high metal contaminations (Cd and Zn) related to an important mining past. In this context, a remediation process has been implemented in 2007 to reduce the watershed contamination. The aim of this study was to assess the early effectiveness of the remediation process on the hydrosystem contamination state. A biomonitoring was realized over two years (2008-2010) with the filter-feeding bivalve Corbicula fluminea, exposed along a contamination gradient. Several biological parameters were monitored: (1) Cd and Zn bioaccumulation, (2) Metallothionein (MT) production as detoxification mechanism, (3) differential gene expression (cat, sod, gst, 12S, cox1, mt). The physicochemical data highlighted strong metal contamination persistence in the river water and failed to demonstrate a significant decrease of metal contamination during the 2-year monitoring. The bioaccumulation results confirmed the persistence of a water contamination despite remediation works, with maximum values measured downstream from the industrial site (Joany). The bioaccumulation increased in 2010, reaching 69.3±5.3μgCdg(-1) DW at Joany in July 2010, whereas it did not exceed 1.4±0.2μgCdg(-1) DW at the reference site throughout the biomonitoring. MT concentrations were closely related to the contamination gradient, especially at Joany, demonstrating their strong involvement in the detoxification processes. The mt gene induction was strongly correlated to the MT and metal concentrations. The gene inductions of cat, sod, gst and 12S were correlated to both the metal concentrations and the seasonal variations, especially temperatures. This suggests that environmental factors require serious consideration for the interpretation of bioaccumulation kinetics and thus for the assessment of the remediation effectiveness. Consequently, the whole results did not yet highlight strong beneficial effects of remediation work on the hydrosystem contamination state. First benefits of that process should be progressively felt, once the remediation achieved, and should grandly accelerate the decontamination process of the contaminated area.
(Chemosphere. vol. 108, n° 0045-6535, pp. 214-224, 01/03/2014)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Expansion of pelagic denitrification during early Pleistocene cooling
Bioavailable nitrogen is removed from the oceans in oxygen-deficient benthic and pelagic environments by denitrification. Future warming is predicted to reduce ocean oxygenation and to cause hypoxic regions to expand, potentially accelerating denitrification. A compilation of high-resolution sedimentary nitrogen isotope (δN15) records from the eastern tropical Pacific, North Pacific, and the Arabian Sea, and a global multi-site survey are presented as evidence for weak pelagic denitrification at the end of the Pliocene warm period. Mean δN15 values increased in the major oxygen minimum zones (OMZs) between 2.1 and 1.5 Ma. Pelagic denitrification strengthened during a period of long term global cooling, despite solubility driven increases in initial oxygen contents of Antarctic intermediate and Subantarctic mode waters ventilating the OMZs. This trend is opposite to the predicted mean trend for a cooling ocean as well as to the observed glacial-interglacial variation. Several alternatives to explain the shift are proposed, including a rise in net respiration, a progressive increase in the ventilation age of the deep ocean associated with million year scale, secular cooling, and a shoaling of the remotely ventilated thermocline to shallow depths corresponding to the zone of peak subsurface respiration. Given no evidence for a net increase in production, we assert that large-scale, climate-driven changes in ocean circulation regulate long timescale variations in the extent of pelagic denitrification. Additional data and modeling are required to fully explain the observations.
(Earth and Planetary Science Letters. vol. 389, n° 0012-821X, pp. 52-61, 01/03/2014)
BTP, 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
Simultaneous 2D Imaging of Dissolved Iron and Reactive Phosphorus in Sediment Porewaters by Thin-Film and Hyperspectral Methods
(Environmental Science and Technology. vol. 48, n° 0013-936X, pp. 2816-2826, 21/02/2014)
BIAF, UA, LPG-ANGERS, LPG, UA, UN UFR ST, UN, INSU - CNRS, CNRS, LPG, UA, UN UFR ST, UN, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IPGP, INSU - CNRS, UPD7, UR, IPG Paris, CNRS
Etude des impacts toxiques des contaminants chimiques du Bassin d'Arcachon sur l'huitre cultivée Crassostrea gigas : Approche in-situ et expérimentale
Le bassin d’Arcachon est une lagune semi-fermée qui concentre de forts enjeux économiques grâce à la pratique de l’ostréiculture. Cette activité est affectée depuis une trentaine d’années par des phénomènes de mortalités estivales, et plus récemment par des surmortalités du naissain. Ces travaux se sont intéressés au rôle des polluants majeurs du bassin d’Arcachon dans ce contexte de crise en étudiant leurs effets sur la biologie de Crassostrea gigas. Une approche in situ a d’abord été adoptée afin d’identifier les contaminants les plus présents dans le milieu naturel. Des opérations de transplantation d’huîtres et des prélèvements de sédiments ont permis de quantifier divers contaminants et d’associer leur présence à des réponses biologiques. Les polluants ainsi identifiés ont ensuite été employés en conditions contrôlées au laboratoire. Trois expérimentations ont été réalisées : la première concerne l’étude des voies de contamination par le tributylétain ; la seconde concerne les effets des pesticides et du cuivre ; la troisième concerne l’effet des HAP sur des huîtres diploïdes et triploïdes. Nos résultats indiquent que les organismes transplantés au coeur de la lagune sont plus exposés aux polluants, en lien avec les caractéristiques hydrodynamiques du système. La plupart des paramètres biologiques étudiés sur le terrain ont par ailleurs montré une saisonnalité liée aux processus de gamétogenèse. Au laboratoire, la plupart des contaminants testés ont induit une réponse adaptative chez les huîtres exposées. Notre étude souligne l’importance de coupler approche de terrain et approche expérimentale pour comprendre le fonctionnement des écosystèmes côtiers.
(19/02/2014)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Facilitative plant interactions and climate simultaneously drive alpine plant diversity
Interactions among species determine local-scale diversity, but local interactions are thought to have minor effects at larger scales. However, quantitative comparisons of the importance of biotic interactions relative to other drivers are rarely made at larger scales. Using a data set spanning 78 sites and five continents, we assessed the relative importance of biotic interactions and climate in determining plant diversity in alpine ecosystems dominated by nurse-plant cushion species. Climate variables related with water balance showed the highest correlation with richness at the global scale. Strikingly, although the effect of cushion species on diversity was lower than that of climate, its contribution was still substantial. In particular, cushion species enhanced species richness more in systems with inherently impoverished local diversity. Nurse species appear to act as a ‘safety net’ sustaining diversity under harsh conditions, demonstrating that climate and species interactions should be integrated when predicting future biodiversity effects of climate change.
(Ecology Letters. vol. 17, n° 1461-023X, pp. 193-202, 01/02/2014)
UdeC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IEU, UZH, UMR AMAP, Cirad, INRA, UM, CNRS, IRD [Occitanie], WSL
Brown muscle disease: impact on Manila clam Venerupis (=Ruditapes) philippinarum biology.
This study assessed the effect of Brown Muscle Disease (BMD) on Manila clam Venerupis philippinarum fitness. BMD was discovered in 2005. It affects the posterior adductor muscle and leads to clam gaping and eventually death. Three statuses of clams were compared: buried individuals with no signs of BMD (BUR); clams at the surface of the sediment with no signs of BMD (SURF) and clams at the surface of the sediment exhibiting signs of brown muscle disease (BMD). Physiological (condition index), immune (hemocyte parameters) and molecular (gene expressions) parameters collected seasonally were analyzed and compared. Results demonstrated a seasonal pattern in condition index (CI) with peaks in spring/summer and decreases in autumn/winter. At each season, the highest CI was observed in BUR and the lowest CI was observed in BMD. In terms of immune response, phagocytosis rate and capacity were higher in clams with BMD whereas the health status of the clams did not influence the total hemocyte count. Genes involved in the immune system (comp, tnf, inter) were upregulated in clams with BMD. The molecular analysis of gill and posterior muscle showed higher mitochondrial metabolism (cox-1, 16S) in cells of infected clams, suggesting a stronger energetic demand by these cells. Finally, genes involved in oxidative stress response (cat, sod), detoxification (mt) and DNA repair (gadd45) were also overexpressed due to reactive oxygen species production. Most of the studied parameters underlined a cause-effect correlation between Manila clam health status (BUR, SUR, BMD) and physiological parameters. An important stress response was observed in BMD-infected clams at different scales, i.e. condition index, immune parameters and stress-related gene expression.
(Fish and Shellfish Immunology. vol. 36, n° 1050-4648, pp. 510-518, 01/02/2014)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEMAR, IRD, IFREMER, UBO EPE, CNRS
Millimeter-Wave Miniaturized Couplers Integrated on BiCMOS Technology
In this article, we present a new wideband hybrid coupler for millimeter‐wave applications realized in the BiCMOS9MW 130‐nm process from STMicroelectronics. The fabrication of two slightly different couplers demonstrates the wideband performance associated with miniaturized size, thanks to the use of meandered transmission lines and lumped capacitors. The best coupler provides a −10‐dB matching bandwidth of 42% with an insertion loss of 0.6 dB and a phase shift of 88° at 60 GHz. The amplitude imbalance and the phase imbalance stay, respectively, within ±1 dB and ±5° over 27 and 36%. These state‐of‐the‐art results are compared to recently published results obtained with comparable hybrid couplers
(Microwave and Optical Technology Letters. vol. 56, n° 0895-2477, pp. 587-590, 28/01/2014)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEAT, UNS, CNRS, UniCA, ST-CROLLES