Etude pluridisciplinaire d’une perturbation industrielle dans l’estuaire de la Gironde : implications du transport et de la dynamique de dégradation des débris végétaux sur le fonctionnement de la source froide du CNPE du Blayais
Jusqu’à présent, la dynamique des fractions végétales n’avait jamais été étudiée dans les estuaires macrotidaux en raison de leur faible quantité, par rapports aux fortes charges en matières en suspension fines, et du manque de protocoles d’étude et d’échantillonnage adéquats. Les débris végétaux sont toutefois à l’origine de perturbations d’activités économiques qui impliquent la filtration de larges volumes d’eau. L’objectif de cette thèse était ainsi de comprendre la dynamique d’apport et de transit de ces débris végétaux dans l’estuaire de la Gironde par la mise en oeuvre d’un suivi spatio-temporel de leur distribution et de techniques nouvelles pour un tel estuaire hyper-turbide (incubations in-situ litter-bag, caractérisation biogéochimique, identification des sources). Les résultats principaux sont la mise en évidence du contrôle du régime hydrologique sur leur distribution et la détermination des échelles de temps de leur persistance dans l’estuaire de la Gironde.
(24/01/2014)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Amazon River carbon dioxide outgassing fuelled by wetlands
River systems connect the terrestrial biosphere, the atmosphere and the ocean in the global carbon cycle. A recent estimate suggests that up to 3 petagrams of carbon per year could be emitted as carbon dioxide (CO2) from global inland waters, offsetting the carbon uptake by terrestrial ecosystems. It is generally assumed that inland waters emit carbon that has been previously fixed upstream by land plant photosynthesis, then transferred to soils, and subsequently transported downstream in run-off. But at the scale of entire drainage basins, the lateral carbon fluxes carried by small rivers upstream do not account for all of the CO2 emitted from inundated areas downstream. Three-quarters of the world's flooded land consists of temporary wetlands, but the contribution of these productive ecosystems to the inland water carbon budget has been largely overlooked. Here we show that wetlands pump large amounts of atmospheric CO2 into river waters in the floodplains of the central Amazon. Flooded forests and floating vegetation export large amounts of carbon to river waters and the dissolved CO2 can be transported dozens to hundreds of kilometres downstream before being emitted. We estimate that Amazonian wetlands export half of their gross primary production to river waters as dissolved CO2 and organic carbon, compared with only a few per cent of gross primary production exported in upland (not flooded) ecosystems. Moreover, we suggest that wetland carbon export is potentially large enough to account for at least the 0.21 petagrams of carbon emitted per year as CO2 from the central Amazon River and its floodplains. Global carbon budgets should explicitly address temporary or vegetated flooded areas, because these ecosystems combine high aerial primary production with large, fast carbon export, potentially supporting a substantial fraction of CO2 evasion from inland waters.
(Nature. vol. 505, n° 0028-0836, pp. 395-398, 16/01/2014)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GET, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France], ULCO, IPGP - UMR_7154, INSU - CNRS, IGN, UR, IPG Paris, CNRS, UPCité, UPCité, BOREA, MNHN, IRD, UPMC, CNRS, NIOZ
Investigating the response of cuproproteins from oysters (Crassostrea gigas) after waterborne copper exposure by metallomic and proteomic approaches
The pacific oyster (Crassostrea gigas), a good model for studying biomineralization and coastal environmental change, was used to study the expression of cuproproteins after waterborne Cu exposure (3 μg Cu L(-1)) similarly to the Arcachon Bay aquatic environment. Cuproproteins in oyster cytosols were analyzed by gel electrophoresis (non-denaturing PAGE and SDS 2-DE), laser ablation inductively coupled plasma mass spectrometry (LA-ICP MS) and electrospray ionization mass spectrometry (ESI-MS). The high molecular weight cuproproteins (identified as extracellular superoxide dismutase [Cu-Zn] (EC Cu/Zn-SOD) and l-ascorbate oxidase) in digestive glands of oysters were differentially expressed after Cu exposure. About 1.7 and 1.2-fold increase of the Cu level in EC Cu/Zn-SOD and l-ascorbate oxidase were, respectively, determined, although EC Cu/Zn-SOD was 1.6-1.9-fold down-regulated in the digestive gland of oysters after Cu exposure. At last, the role of EC Cu/Zn-SOD in protection against Cu exposure was discussed to propose possible mechanisms to better understand Cu homeostasis and/or detoxification mechanisms.
(Metallomics. vol. 6, n° 1756-5901, pp. 338, 15/01/2014)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IPREM, UPPA, INC-CNRS, CNRS
Improved Measurement Accuracy of Probe-Fed mm-Wave Antennas Using the Three Method
In this letter, we present a method to extract the scattering parameters of a microelectronic probe used to feed on-chip or in-package antennas at millimeter-wave frequencies. It is especially important to take into account these losses in the calibration procedure necessary for the extraction of the antenna gain. We are specifically demonstrating that these losses are positively or negatively impacted, depending on the impedance value of the input impedance of the antenna connected to the probe. Theory is detailed and examples are given to illustrate the importance of taking into account those losses with precision. From the S-parameters of the probe and the measurement of the reflection coefficient of the antenna, we can compute the gain from the measured realized gain. An accuracy improvement of 15% is shown for the gain of the presented antenna.
(IEEE Antennas and Wireless Propagation Letters. vol. 13, n° 1536-1225, pp. 103-105, 06/01/2014)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEAT-CNRS-UMR7248, UNS, CNRS, UniCA, ST-CROLLES
2000years of frequent turbidite activity in the Capbreton Canyon (Bay of Biscay)
Capbreton Canyon extends from 200 m water depth near the Aquitanian coast to 3000 m water depth before abruptly turning northward and merging with the Cap-Ferret systems. The Capbreton Canyon has been disconnected from the Adour River input since 1310 AD. Despite this situation, modern sedimentary activity is evident in the first kilometres from the head. Present sedimentation in the Capbreton Canyon was studied by combined analysis of acoustic data and cores. Cores from the topographic highs document moderate hemipelagic sedimentation and record the global climatic signal of the Bay of Biscay. Within the canyon, at±80 km from the head, on terraces bordering the thalweg at 1600 mwater depth, cores attest to recent turbidite activity.Massive medium sand is restricted to the thalweg floor, where sediment transfer dominates. Fine-grained turbidites are preferentially accumulated on the shallower terraces near the thalweg (the accumulation rate is 3 and 1 cm/year at 75 m and 125 m above the thalweg, respectively). On a higher terrace (225 m), turbidite sequences are absent or too thin to be preserved frombioturbation. The sedimentation rate is lower (approximately 0.17 cm/year) but still 10 times higher than the hemipelagic sedimentation outside the Capbreton Canyon. We demonstrate that frequent turbidity currents (1/year) are currently responsible for very high accumulation of dominantly fine-grained sediments on the terraces that are the nearest from the thalweg. We assume an impact of nepheloid layers on the sedimentation of the highest terraces. Looking for any impact on sediment supply of the disconnection of the Capbreton Canyon head from the Adour River mouth, it appears that the impact on the sedimentation affected the nature of the particles, which are less carbonate-rich, rather than the quantity of sediments. This result suggests that the longshore drift at the canyon head and hydrodynamic events are major factors in the sedimentation of Capbreton Canyon.
(Marine Geology. vol. 347, n° 0025-3227, pp. 136-152, 01/01/2014)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Neutralized Coupling Elements for MIMO Operation in 4G Mobile Terminals
A novel multiple-input-multiple-output (MIMO) dual-antenna system covering the low LTE700 and GSM850/900 communication standards is proposed for mobile terminals. The two-port antenna system is composed of two 3-D coupling elements, placed on the vertices of the short corner of a rectangular FR4 substrate. This rectangular shape emulates the printed circuit board of a modern mobile terminal. To achieve high port-to-port isolation, the neutralization technique is applied. Simulated reflection coefficients, total efficiencies, and envelope coefficient correlation are compared to measured data showing good agreement and competitive performance.
(IEEE Antennas and Wireless Propagation Letters. vol. 13, n° 1536-1225, pp. 141-144, 01/01/2014)
LEAT-CNRS-UMR7248, UNS, CNRS, UniCA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Spatially Modulated Orthogonal Space-Time Block Codes with Non-Vanishing Determinants
This paper proposes a multiple-input multiple-output (MIMO) transmission scheme for M-ary modulations, called Spatially Modulated Orthogonal Space-Time Block Coding (SM-OSTBC), based on the concept of Spatial Constellation (SC) codewords introduced by Le at el. . In the proposed scheme, transmit codeword matrices are generated by multiplying SC matrices with codewords constructed from Orthogonal Space-time Block Codes (O-STBC). The maximum spectral efficiency of the proposed scheme is equal to (n_T-2+ log_2 M) bpcu, where n_T is the number of transmit antennas and M is the modulation order. The SC matrices provide a means of carrying information bits together with the O-STBC codewords and allow the SM-OSTBC scheme to achieve second-order transmit diversity by satisfying the non-vanishing determinant property. A systematic method to design the SC codewords for an even number of transmit antennas greater than 3 is presented. A single-stream maximum-likelihood (ML) decoder, which requires a low computational complexity thanks to the structure of the SM-OSTBC codewords and to the orthogonality of the O-STBCs, and a sphere decoder with further reduced signal processing complexity are developed. The bit error rate (BER) performance of the proposed scheme is studied by using both theoretical union bound analysis and computer simulations. Finally, simulation results are presented in order to compare BER performance, energy efficiency and decoding complexity of the proposed scheme with those of several existing MIMO transmission schemes.
(IEEE Transactions on Communications. vol. 62, n° 0090-6778, pp. 85 - 99, 01/01/2014)
HUST, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, L2S, UP11, CNRS
A 1D stabilized finite element model for non-hydrostatic wave breaking and run-up
(. vol. 77, 26/10/2026)
BACCHUS, Inria, UB, CNRS, IMB, UB, Bordeaux INP, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Réduction des micropolluants par les traitements complémentaires : fossé construit sur sol imperméable, filtres garnis de matériaux adsorbants (ARMISTIQ – Action B)
Le projet ARMISTIQ (« Amélioration de la réduction des micropolluants dans les stations de traitement des eaux usées domestiques ») a pour objectif d’évaluer et d’améliorer la connaissance et la maîtrise de technologies de traitements secondaire et complémentaire des substances prioritaires et émergentes présentes dans les eaux usées et les boues urbaines. L’action B porte sur deux procédés complémentaires susceptibles d’éliminer des micropolluants contenus dans les rejets de stations de traitement des eaux usées des communes rurales. Il s’agissait d’une part, d’étudier les rendements d’élimination de micropolluants par un fossé de 80 mètres de long construit sur sol imperméable (installation grandeur réelle), et d’autre part, d’étudier les rendements d’élimination de micropolluants par trois matériaux rapportés, adsorbants en grain (charbon actif, zéolite ou argile expansée), étudiés à l’échelle du laboratoire et à l’échelle de pilotes semi-industriels. Des protocoles d’analyses chimiques, fiables et robustes, ont été appliqués pour déterminer les concentrations de 16 métaux, 19 médicaments, 19 hydrocarbures aromatiques polycycliques (HAP), 6 alkylphénols (AKP) et 6 pesticides, choisis en raison de leurs différentes propriétés physicochimiques et leur persistance aux traitements secondaires. Le fossé de 80 mètres de long construit sur sol imperméable a montré une efficacité très limitée vis-à-vis de la réduction des micropolluants étudiés (rendements inférieurs à 30% pour les micropolluants réfractaires au traitement secondaire). Néanmoins, des rendements d’élimination compris entre 30 et 70% ont été mesurés pour quelques substances qui s’expliquent soit par adsorption sur l’argile du sol pour quelques métaux (cobalt, zinc, cadmium) soit par photodégradation pour quelques micropolluants organiques (paracétamol, ibuprofène). Des rendements d’élimination proches de 100% pendant plus de 330 jours ont été mesurés pour le filtre à charbon actif fonctionnant avec un temps de séjour hydraulique (HRT) de 1,5 heure. Seul le nonylphénol et quelques métaux ont eu des rendements moindres (50 à 80%). Un kilogramme de charbon actif a adsorbé les micropolluants contenus dans au moins 8 m3 d’eau usée traitée. Des rendements d’élimination supérieurs à 70% pour la moitié des substances pharmaceutiques et phytosanitaires étudiées ont été mesurés pour les filtres garnis de matériaux adsorbants en grain (argile expansée ou zéolite), alternatifs au charbon actif, avec un HRT de 24 heures. Les rendements d’élimination obtenus pour les autres substances sont bien moindres qu’avec le charbon actif, mais restent supérieurs à ceux mesurés avec des filtres à graviers ou à apatite. Un kilogramme d’argile ou de zéolite a adsorbé les micropolluants contenus dans environ 0,3 m3 d’eau usée traitée, et les filtres ont saturé au bout de quelques mois. Avec un HRT plus court (4 heures), la saturation est intervenue au bout d’une vingtaine de jours seulement. Les perspectives de ce travail concernent l’évaluation d’autres procédés complémentaires, comprenant une succession de bassins de faibles profondeurs d’eau libre, ainsi que des procédés construits sur sol perméable.
(pp. 64, 26/10/2026)
UR MALY, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Bioaccumulation of perfluoroalkyl compounds in midge (Chironomus riparius) larvae exposed to sediment
Midge larvae (Chironomus riparius) were exposed to sediments from a deposition sampled at a site along the Rhône River (France) downstream of an industrial site releasing various perfluorinated chemicals. This sediment is characterized by high concentrations of perfluoroundecanoic acid (PFUnA) and perfluorotridecanoic acid (PFTrDA) and a low perfluorooctane sulfonate (PFOS) concentration. Concentrations of 23 perfluoroalkyl compounds, including C4eC14 carboxylate acids, C4eC10 sulfonates, and seven precursors, were analyzed in overlying and pore water, sediment, and larvae. Midge larvae accumulated carboxylate acids (C11eC14), PFOS, and two precursors (perfluorooctane sulfonamide: FOSA and 6:2 fluorotelomer sulfonic acid, 6:2 FTSA). These substances accumulated mainly during the fourth instar larvae exponential growth phase. Accumulation of 6:2 FTSA, PFUnA, and PFOS occured via trophic and tegumentary routes. Other compounds mainly accumulated from food. Kinetics followed a partition model, from which uptake and elimination constants were derived.
(Environmental Pollution. vol. 189, n° 0269-7491, pp. p. 27 - p. 34, 26/10/2026)
UR MALY, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ECCC