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Pore scale monitoring of the resting period and oxygenation of filtering media in Vertical Flow Treatment Wetland by X-ray tomography | Suivi de la période de repos de la couche filtrante des filtres plantés de roseaux par tomographie RX
2018
Martinez Carvajal, G. | Oxarango, L. | Molle, Pascal | Forquet, N.
This study aims to enlighten the geometric changes at the pore scale of filtering media of Vertical Flow Treatment Wetlands (VFTW) and their influence on oxygenation during the rest period. A 3-day ex-situ drying of six samples of a VFTW was carried out at controlled temperature, and relative humidity simulating the rest period. Samples (16-cm long) were taken at the end of the feeding period of a filter in the first stage and let dry. Three of the samples were sterilized before drying using gamma rays to differentiate oxygenation without bacterial activity. At 0, 1 and 3 days of drying, X-ray scans of the samples were performed to observe changes in the samples structure. After each scan, the oxygen transport within the sample was studied by measuring vertical oxygen concentration profiles. Although X-ray tomography allows small structure changes to be detected, it is necessary to modify the drying conditions perform a more realistic drying. The complexity of the results of oxygen profiles lead us to suggest the use of CFD tools to understand how oxygenation occurs.
Afficher plus [+] Moins [-]Écologie Urbaine : Quoi, Pourquoi, Comment ?
2018
Abbadie, Luc | Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris ) ; Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Monitoring mangrove forests after aquaculture abandonment using time series of very high spatial resolution satellite images: A case study from the Perancak estuary, Bali, Indonesia
2018
Proisy, Christophe | Viennois, Gaëlle | Sidik, Frida | Andayani, Ariani | Enright, James Antony | Guitet, Stéphane | Gusmawati, Niken | Lemonnier, Hugues | Muthusankar, Gowrappan | Olagoke, Adewole, A | Prosperi, Juliana | Rahmania, Rinny | Ricout, Anaïs, A | Soulard, Benoit | Suhardjono, X | Institut Français de Pondichéry (IFP) ; Ministère de l'Europe et des Affaires étrangères (MEAE)-Centre National de la Recherche Scientifique (CNRS) | Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP) ; Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]) | The Ministry of Marine Affairs and Fisheries | Mangrove Action Project | Groupement d'Interêt Public Ecosystèmes Forestiers GIP ECOFOR (GIP ECOFOR ) | Ifremer - Nouvelle-Calédonie ; Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER) | Université de la Nouvelle-Calédonie (UNC) | Technische Universität Dresden = Dresden University of Technology (TU Dresden) | Indonesian Institute of Sciences (LIPI) | Projet INDESO; http://www.indeso.web.id
International audience | Revegetation of abandoned aquaculture regions should be a priority for any integrated coastal zone management (ICZM). This paper examines the potential of a matchless time series of 20 very high spatial resolution (VHSR) optical satellite images acquired for mapping trends in the evolution of mangrove forests from 2001 to 2015 in an estuary fragmented into aquaculture ponds. Evolution of mangrove extent was quantified through robust multitemporal analysis based on supervised image classification. Results indicated that mangroves are expanding inside and outside ponds and over pond dykes. However, the yearly expansion rate of vegetation cover greatly varied between replanted ponds. Ground truthing showed that only Rhizophora species had been planted, whereas natural mangroves consist of Avicennia and Sonneratia species. In addition, the dense Rhizophora plantations present very low regeneration capabilities compared with natural mangroves. Time series of VHSR images provide comprehensive and intuitive level of information for the support of ICZM.
Afficher plus [+] Moins [-]Traitement de l'azote global d'effluents concentrés et avec variations de charges par filtres plantés de végétaux avec aération forcée | Total nitrogen removal of highly concentrated and variable influents by treatment wetlands using forced aeration
2018
Prost Boucle, S. | Garcia, Oscar | Troesch, S. | Masson, M. | Petitjean, Anne | Molle, Pascal
Intensified treatment wetlands can reduce treatment wetlands footprint, improve efficiencies and deal with unusual influent characteristics. A specific design of 750 p.e. has been implemented for a highway rest area in France.
Afficher plus [+] Moins [-]The pesticide chlordecone is trapped in the tortuous mesoporosity of allophane clays
2018
Woignier, Thierry | Clostre, Florence | Fernandes, Paula | Soler, Alain | Rangon, Luc | Sastre-Conde, Maria Isabel | Jannoyer-Lesueur, Magalie
Some volcanic soils like andosols contain short-range order nanoclays (allophane) which build aggregates with a tortuous and fractal microstructure. The aim of the work was to study the influence of the microstructure and mesoporosity of the allophane aggregates on the pesticide chlordecone retention in soils. Our study shows that the allophane microstructure favors pollutants accumulation and sequestration in soils. We put forth the importance of the mesoporous microstructure of the allophane aggregates for pollutant trapping in andosols. We show that the soil contamination increases with the allophane content but also with the mesopore volume, the tortuosity, and the size of the fractal aggregate. Moreover, the pore structure of the allophane aggregates at nanoscale favors the pesticide retention. The fractal and tortuous aggregates of nanoparticles play the role of nanolabyrinths. It is suggested that chlordecone storage in allophanic soils could be the result of the low transport properties (permeability and diffusion) in the allophane aggregates. The poor accessibility to the pesticide trapped in the mesopore of allophane aggregates could explain the lower pollutant release in the environment. (Résumé d'auteur)
Afficher plus [+] Moins [-]Spatial variations in trace element concentrations of the sea urchin, Paracentrotus lividus, a first reference study in the Mediterranean Sea
2018
Ternengo, Sonia | Marengo, Michel | El Idrissi, Ouafa | Yepka, Joseph | Pasqualini, Vanina | Gobert, Sylvie | FOCUS - Freshwater and OCeanic science Unit of reSearch - ULiège
peer reviewed | A study on Trace Elements (TE) from sea urchin gonads has been conducted in the western Mediterranean Sea. Contamination data were used to determine a Trace Method Pollution Index (TEPI). TE concentrations varied considerably depending on the location of the sampling stations. The results showed that five trace elements (Zn, Fe, As, Al, Cu) are ubiquitous. The geographical area considered (Corsica) represents an important range of environmental conditions and types of pressure that can be found in the western Mediterranean Sea. TEPI was used to classify the studied sites according to their degree of contamination and allowed reliable comparison of TE contamination between local and international sites. TE contamination of the western Mediterranean Seadisplayed a north-to-south gradient, from the Italian coasts down through the insular Corsican coasts to the north African littoral. Due to the increasing environmental pressure on the Mediterranean Sea, a regular monitoring of TE levels in marine organisms is necessary to prevent any further environmental deterioration.
Afficher plus [+] Moins [-]Full scale experience of granulated apatite filters for phosphorous retention in treatment wetlands. | Retour d'expérience des filtres d'apatite granulée en taille réelle pour la rétention du phosphore dans les filtres plantés de roseaux
2018
Delgado Gonzalez, L. | Gerbier, C. | Prost-Boucle, Stéphanie | Troesch, S. | Molle, Pascal | Réduire, valoriser, réutiliser les ressources des eaux résiduaires (UR REVERSAAL) ; Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA) | SYNTEA CAUMONT SUR DURANCE FRA ; Partenaires IRSTEA ; Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)
[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED [ADD1_IRSTEA]Valoriser les effluents et déchets organiques | International audience | There are 20 full-scale Phosclean® filters for P removal being used together with treatment wetlands (TW) to treat wastewaters of small and medium-size communities, in France. Some of them are in operation for more than five years now, reason why some field experiences are being conducted under the project name of APPROVE (APatite for P Removal and Valorisation: an Evaluation) to assess the current performance and saturation conditions of full-scale filters. This paper will present fieldfeedback results from 4 different wastewater treatment plants (WWTP) with Phosclean® filters. WWTP A (filter A) has been monitored since its commission in 2017 to assess the effluent's pH evolution due to material dissolution in the very first stage of its life span. Three other WWTPs (B, C and D) with hydraulically different Phosclean® filters, in operation since 2012, are also monitored: vertical up-flow (filter B); vertical down-flow (filter C) and horizontal flow (filter D). Assessment of the treatment plants use regulatory surveys since the beginning of plants operations. As treatment plants have not the same capacity, the number of regulatory surveys is heterogeneous and not high enough to have a precise knowledge on saturation levels and retention kinetics. Consequently, additional measurement campaigns have been carried out over two years. Four-day campaigns have been carried out twice per year for each WWTP. In order to evaluate the P retention's performance, 24h-flow proportional samplings at the inlet and outlet of the Phosclean® filter were coupled to spotsamplings at different hydraulic retention times inside the filter to measure retention's kinetic. Online P-PO4 measurements at the outlet of the filter were also conducted to observe possible dynamic within a day. Mayor parameters as pH, conductivity, redox potential, TSS, BOD, COD, N, TP, P-PO4 3- as well as anions and cations were measured for these samples. For filter A, a flowmeter and an online pH probe at the outlet of the filter have been implemented for several months. To determine the nature of phosphate precipitates, SEM and DRX analyses were performed for solid samples taken at different points in the filters. Furthermore, fluorescein-tracer tests were carried out to precisely determine water retention times and possible short-circuiting, as well as dynamic penetrometer measurements to assess potential changes on the material density due to surface precipitation. Results of first campaigns show that P concentration at the outlet of filters C and D respect the maximal regulation limit for total phosphorous disposal after 5 years of operation. This is not the case for filter B, after 4 years of operation, which is over the regulation limit fixed at 2.5mgTP/L. Nevertheless, differences in the regulation limits, inlet P concentrations, hydraulic loads, operation and design, must be taken into consideration to analyze variations of filters performances. The evolution of TP concentrations along time will be presented for all filters according to saturation levels for comparison. Kinetics evolution as a function of saturation conditions will be also presented. Results show that filters B, C and D are at different saturation levels, being filter B the most saturated.
Afficher plus [+] Moins [-]Pore scale monitoring of the resting period and oxygenation of filtering media in Vertical Flow Treatment Wetland by X-ray tomography | Suivi de la période de repos de la couche filtrante des filtres plantés de roseaux par tomographie RX
2018
Martinez Carvajal, G. | Oxarango, L. | Molle, Pascal | Forquet, Nicolas | Réduire, valoriser, réutiliser les ressources des eaux résiduaires (UR REVERSAAL) ; Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA) | Institut des Géosciences de l’Environnement (IGE) ; Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Observatoire des Sciences de l'Univers de Grenoble (Fédération OSUG)
[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED [ADD1_IRSTEA]Valoriser les effluents et déchets organiques | International audience | This study aims to enlighten the geometric changes at the pore scale of filtering media of Vertical Flow Treatment Wetlands (VFTW) and their influence on oxygenation during the rest period. A 3-day ex-situ drying of six samples of a VFTW was carried out at controlled temperature, and relative humidity simulating the rest period. Samples (16-cm long) were taken at the end of the feeding period of a filter in the first stage and let dry. Three of the samples were sterilized before drying using gamma rays to differentiate oxygenation without bacterial activity. At 0, 1 and 3 days of drying, X-ray scans of the samples were performed to observe changes in the samples structure. After each scan, the oxygen transport within the sample was studied by measuring vertical oxygen concentration profiles. Although X-ray tomography allows small structure changes to be detected, it is necessary to modify the drying conditions perform a more realistic drying. The complexity of the results of oxygen profiles lead us to suggest the use of CFD tools to understand how oxygenation occurs.
Afficher plus [+] Moins [-]Accumulate or eliminate? Seasonal mercury dynamics in albatrosses, the most contaminated family of birds
2018
Cherel, Yves | Barbraud, Christophe | Lahournat, Maxime | Jaeger, Audrey | Jaquemet, Sébastien | Wanless, Ross | Phillips, Richard, T. | Thompson, David | Bustamante, Paco | Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC) ; Institut National de la Recherche Agronomique (INRA)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS) | LIttoral ENvironnement et Sociétés (LIENSs) ; La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS) | Ecologie marine tropicale dans les Océans Pacifique et Indien (ENTROPIE [Réunion]) ; Institut de Recherche pour le Développement (IRD)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS) | University of Cape Town | British Antarctic Survey (BAS) ; Natural Environment Research Council (NERC)
International audience | Albatrosses (Diomedeidae) are iconic pelagic seabirds whose life-history traits (longevity, high trophic position) put them at risk of high levels of exposure to methylmercury (MeHg), a powerful neurotoxin that threatens humans and wildlife. Here, we report total Hg (THg) concentrations in body feathers from 516 individual albatrosses from 35 populations, including all 20 taxa breeding in the Southern Ocean. Our key finding is that albatrosses constitute the family of birds with the highest levels of contamination by Hg, with mean feather THg concentrations in different populations ranging from moderate (3.8 mg/g) to exceptionally high (34.6 mg/g). Phylogeny had a significant effect on feather THg concentrations, with the mean decreasing in the order Diomedea > Phoebetria > Thalassarche. Unexpectedly, moulting habitats (reflected in feather d13C values) was the main driver of feather THg concentrations, indicating increasing MeHg exposure with decreasing latitude, from Antarctic to subtropical waters. The role of moulting habitat suggests that the majority of MeHg eliminated into feathers by albatrosses is from recent food intake (income strategy). They thus differ from species that depurate MeHg into feathers that has been accumulated in internal tissues between two successive moults (capital strategy). Since albatrosses are amongst the most threatened families of birds, it is noteworthy that two albatrosses listed as Critical by the World Conservation Union (IUCN) that moult and breed in temperate waters are the most Hg-contaminated species (the Amsterdam and Tristan albatrosses). These data emphasize the urgent need for robust assessment of the impact of Hg contamination on the biology of albatrosses and they docu-ment the high MeHg level exposure of wildlife living in the most remote marine areas on Earth.
Afficher plus [+] Moins [-]Microplastic bacterial communities in the Bay of Brest: Influence of polymer type and size
2018
Frère, Laura | Maignien, Loïs | Chalopin, Morgane | Huvet, Arnaud | Rinnert, Emmanuel | Morrison, Hilary | Kerninon, Sandrine | Cassone, Anne-Laure | Lambert, Christophe | Reveillaud, Julie | Paul-Pont, Ika | Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR) ; Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM) ; Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) | Laboratoire de Microbiologie des Environnements Extrêmophiles (LM2E) ; Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) | Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER) | Marine Biological Laboratory (MBL) ; University of Chicago | LABOCEA Laboratoire [Plouzané, France] | Animal, Santé, Territoires, Risques et Ecosystèmes (UMR ASTRE) ; Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA) | ANR-15-CE34-0006,Nanoplastics,Microplastiques, nanoplastiques dans l'environnement marin: caractérisation, impacts et évaluation des risques sanitaires.(2015)
International audience | Microplastics (<5 mm) exhibit intrinsic features such as density, hydrophobic surface, or high surface/volume ratio, that are known to promote microbial colonization and biofilm formation in marine ecosystems. Yet, a relatively low number of studies have investigated the nature of microplastic associated bacterial communities in coastal ecosystems and the potential factors influencing their composition and structure. Here, we characterized microplastics collected in the Bay of Brest by manual sorting followed by Raman spectroscopy and studied their associated bacterial assemblages using 16S amplicon high-throughput sequencing. Our methodology allowed discriminating polymer type (polyethylene, polypropylene and polystyrene) within small size ranges (0.3-1 vs. 1-2 vs. 2-5 mm) of microplastics collected. Data showed high species richness and diversity on microplastics compared to surrounding seawater samples encompassing both free living and particle attached bacteria. Even though a high proportion of operational taxonomic units (OTU; 94 ± 4%) was shared among all plastic polymers, polystyrene fragments exhibited distinct bacterial assemblages as compared to polyethylene and polypropylene samples. No effect of microplastic size was revealed regardless of polymer type, site and date of collection. The Vibrio genus was commonly detected in the microplastic fraction and specific PCR were performed to determine the presence of potentially pathogenic Vibrio strains (namely V. aestuarianus and the V. splendidus polyphyletic group). V. splendidus related species harboring
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