Impact of Lebanese practices in industry, agriculture and urbanization on soil toxicity. Evaluation of the Polycyclic Aromatic Hydrocarbons (PAHs) levels in soil
(Chemosphere. vol. 210, n° 0045-6535, pp. 85-92, 01/11/2018)
LAEC-CNRS, CNRS-L, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LU / ULB, LU / ULB, LPTC, UB, CNRS
Inventory, dynamics and impact of the trematodes parasites in bivalves with high economic importance
Among population dynamics drivers, parasitism is significant but often neglected. Beyond inventory of the various parasites, it is urgent to understand the susceptibility of hosts, namely bivalves, to infection, and to investigate the interaction among parasites and other environmental conditions.In this way, the present study aimed to characterize and quantify the trematode macroparasites, the most abundant and prevalent in coastal waters, infecting Cerastoderma edule and Donax trunculus, which are among the most ecologically important and economically explored bivalve species in Portugal and France.The first step was to study bivalve population dynamics, evaluating the relationship between temperature and recruitment timing and the reciprocal effects of recruitment on adult biomass. For this, a large database spanning 17 years of monthly observations of a cockle population inhabiting a national protected area (Banc d’Arguin, Arcachon, France) was analysed. Long-term observations showed that the sustainability of a cockle population is recruitment-success dependent. In cockles, recruitment success showed to be partly, but not only, dependent on temperature. Hence, the sustainability of a cohort could be set earlier, i.e. by processes happening before recruitment. Following this clue, the role of parasitism on the bivalve host population dynamics was explored.Firstly, due to high pathogenicity for bivalves, special attention was given to the parasites Bucephalus minimus and Bacciger bacciger which use C. edule and D. trunculus, respectively, as first intermediate hosts (where their sporocysts parasitic stage develops). […]Then, the study focused on metacercariae infection in its bivalve second intermediate host, a relationship that is usually reported as less deleterious. […]Lastly, the susceptibility of bivalves to parasites infection when challenged by climate change related factors (salinity, temperature and pH) and contamination (Arsenic) was experimentally assessed. Main results showed that hosts exposure to stressful conditions related to global change scenarios can modify the parasite infection success and induced host biochemical response alterations.The findings presented in this thesis improved the knowledge on the effects of different constraints on bivalves, highlighting the crucial role of parasitism. If applied, these new insights can promote the sustainable management of bivalves, such an important marine resource, with greater production and economic potential.
(29/10/2018)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Modeling airborne nanoparticle filtration through a complete structure of non-woven material used in protective apparel
Airborne nanoparticles represent a new danger in occupational health. Numerous theoretical and experimental studies have been conducted on the efficiency of filtering media used for respiratory protection, but few have focused on media used for skin protective equipment. Indeed, a significant proportion of airborne nanoparticles can end up on the skin, causing local effects and eventually penetrating the human body. Following experimental data obtained with sodium chloride nanoparticles, the authors propose an empirical model to evaluate the penetration of airborne nanoparticles through medium used in disposable coveralls. This study presents an adaptation of the conventional filtration theory used for filtering media used in respirators. The authors' model is compared with Wang et al.'s and Brochot's models and demonstrates improvements in their descriptive ability. Moreover, a domain of validity of the proposed model was determined that will enable the evaluation of the efficiency of similar protective apparel material structures against airborne nanoparticles.
(Textile Research Journal. vol. 89, n° 0040-5175, pp. 3024-3033, 10/10/2018)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Évolution morphologique actuelle d'une flèche littorale holocène : le Cap Ferret, à l'embouchure du Bassin d'Arcachon
La flèche littorale du Cap Ferret s'est édifiée au cours des derniers 3 000 ans, à la faveur du ralentissement de l'élévation du niveau global des océans. Depuis 250 ans, les cartes marines révèlent une importante instabilité de l'extrémité libre de la flèche, à laquelle les travaux présentés dans ce mémoire tentent d'apporter une explication physique. Dans un premier temps le croisement des données cartographiques avec des données environnementales révèle la synchronisation des déplacements de la flèche avec d'une part l'Oscillation Nord Atlantique (NAO), et, d'autre part, les structuations décennales à multidécennales de la vitesse de l'élévation du niveau de l'Atlantique Nord-est. Les processus sous-jacents à cette synchronisation sont alors détaillés avec un modèle numérique de transport sédimentaire. Puis, l'érosion chronique de la flèche entre 1986 et 2016, ainsi que les mécanismes d'évolution de la plage océanique de la Pointe du Cap Ferret sont décrits et quantifiés à l'aide de données topographiques. A l'échelle locale, ces résultats apportent des preuves tangibles du rôle du climat dans l'érosion actuelle de la Pointe du Cap Ferret. D'un point de vue plus général, ces travaux contribuent à la meilleure description des processus contrôlant l'évolution des systèmes de barrières holocènes, dans le contexte actuel d'accélération de l'élévation du niveau de la mer.
(05/10/2018)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Couplage d'archives sédimentologiques et historiques pour étudier 150 années d'évènement extrêmes dans la lagune de la Petite mer des Gâvres, France
(The poster is in French language) This study exposes a 150 years high-resolution record of extreme wave events from a multi-proxy analysis of sedimentary deposits from a coastal depositional environment of the Western French coast. We analyze the Petite Mer de Gâvres lagoon, a wetland located behind a sandy barrier, where evidence for strong extratropical storms have been identified since 1850. Four short sediment cores were collected in August 2016 using a Beeker gravity corer from two different sites into this lagoon. Sediments were extracted behind a thick and a thin section of the sandy barrier to compare different stormy impacts depending on their environment. High-resolution elemental analyses of sediment cores were done using an Avaatech XRF core scanner, and X-radiographs were taken using a Scopix system. With the high resolution sediment sampling of 0.5 cm, grain size analysis was done using a Malvern 2600 laser beam grain sizer. We also tested to find new geochemical proxies testifying marine intrusions in the Petite Mer de Gâvres, as previous attempts to define geochemical indicators of past storms for the European Atlantic coast are missing in literature. These new proxies then helped us in the identification of sedimentological washovers.137Cs and 210Pb dating has been proceeded from measurements of 2 g dried sediment using a low background, Camberra well-type γ spectrometer. Combined with our dense historical resources, these strong events have been associated with the precise date of past storms that impacted the study site, with important details about the damages caused by these events. The historical information has been researched using archives including narrative sources, surveys conducted after a disaster, newspapers from different departmental and national archives, and meteorological data from Meteo France. Results show that in the Petite Mer de Gâvres, six extreme episodes can be observed, including an 1896 AD intense washover due to a violent extratropical storm that may have breached the sandy barrier of the Petite Mer de Gâvres lagoon.
(04/10/2018)
LETG, UNICAEN, NU, UA, EPHE, PSL, UBO EPE, UR2, CNRS, IGARUN, UN, LETG - Nantes, UNICAEN, NU, EPHE, PSL, UBO EPE, UR2, CNRS, IGARUN, UN, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UN
Trematode infection modulates cockles biochemical response to climate change
Resulting mainly from atmospheric carbon dioxide (CO2) build-up, seawater temperature rise is among the most important climate change related factors affecting costal marine ecosystems. Global warming will have implications on the water cycle, increasing the risk of heavy rainfalls and consequent freshwater input into the oceans but also increasing the frequency of extreme drought periods with consequent salinity increase. For Europe, by the end of the century, projections describe an increase of CO2 concentration up to 1120 ppm (corresponding to 0.5 pH unit decrease), an increase in the water temperature up to 4 °C and a higher frequency of heavy precipitation. These changes are likely to impact many biotic interactions, including host–parasite relationships which are particularly dependent on abiotic conditions. In the present study, we tested the hypothesis that the edible cockle, Cerastoderma edule, exposed to different salinity, temperature and pH levels as proxy for climate change, modify the infection success of the trematode parasite Himasthla elongata, with consequences to cockles biochemical performance. The results showed that the cercariae infection success increased with acidification but higher biochemical alterations were observed in infected cockles exposed to all abiotic experimental stressful conditions tested. The present study suggested that changes forecasted by many models may promote the proliferation of the parasites infective stages in many ecosystems leading to enhanced transmission, especially on temperate regions, that will influence the geographical distribution of some diseases and, probably, the survival capacity of infected bivalves.
(Science of the Total Environment. vol. 637-638, n° 0048-9697, pp. 30-40, 01/10/2018)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Environmental factors controlling biomass development of seagrass meadows of Zostera noltei after a drastic decline (Arcachon Bay, France)
(Journal of Sea Research (JSR). vol. 140, n° 1385-1101, pp. 87-104, 01/10/2018)
LERAR, COAST, IFREMER, IMB, UB, Bordeaux INP, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Basin tectonic history and paleo-physiography of the pelagian platform, northern Tunisia, using vitrinite reflectance data
Constraining the thermal, burial and uplift/exhumation history of sedimentary basins is crucial in the understanding of upper crustal strain evolution and also has implications for understanding the nature and timing of hydrocarbon maturation and migration. In this study, we use Vitrinite Reflectance (VR) data to elucidate the paleo‐physiography and thermal history of an inverted basin in the foreland of the Atlasic orogeny in Northern Tunisia. In doing so, it is the primary aim of this study to demonstrate how VR techniques may be applied to unravel basin subsidence/uplift history of structural domains and provide valuable insights into the kinematic evolution of sedimentary basins. VR measurements of both the onshore Pelagian Platform and the Tunisian Furrow in Northern Tunisia are used to impose constraints on the deformation history of a long‐lived structural feature in the studied region, namely the Zaghouan Fault. Previous work has shown that this fault was active as an extensional structure in Lower Jurassic to Aptian times, before subsequently being inverted during the Late Cretaceous Eocene Atlas I tectonic event and Upper Miocene Atlas II tectonic event. Quantifying and constraining this latter inversion stage, and shedding light on the roles of structural inheritance and the basin thermal history, are secondary aims of this study. The results of this study show that the Atlas II WNW‐ESE compressive event deformed both the Pelagian Platform and the Tunisian Furrow during Tortonian‐Messinian times. Maximum burial depth for the Pelagian Platform was reached during the Middle to Upper Miocene, i.e. prior to the Atlas II folding event. VR measurements indicate that the Cretaceous to Ypresian section of the Pelagian Platform was buried to a maximum burial depth of ~3 km, using a geothermal gradient of 30°C/km. Cretaceous rock samples VR values show that the hanging wall of the Zaghouan Fault was buried to a maximum depth of <2 km. This suggests that a vertical km‐scale throw along the Zaghouan Fault pre‐dated the Atlas II shortening, and also proves that the fault controlled the subsidence of the Pelagian Platform during the Oligo‐Miocene. Mean exhumation rates of the Pelagian Platform throughout the Messinian to Quaternary were in the order of 0.3 mm/year. However, when the additional effect of Tortonian‐Messinian folding is accounted for, exhumation rates could have reached 0.6–0.7 mm/year.
(Basin Research. vol. 30, n° 0950-091X, pp. 926-941, 01/10/2018)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UiB, INSU - CNRS, UM, CNRS, UA, UB
Wave Runup Over Steep Rocky Cliffs
Wave runup is known to depend on offshore wave conditions and coastal morphology. While most field studies on wave runup have focused on low-to-mild-sloping sandy beaches, runup measurements on steep and irregular rocky cliff profiles are still very scarce. Here we investigate the physical processes controlling wave runup in such environments and the range of applicability of empirical runup formula. This study focuses on the steep rocky cliffs (0.1 < taní µí»½ < 0.4) of Banneg Island, a small island located in the Molène archipelago, Brittany, France, occasionally flooded during extreme water level events. A statistical parameter for extreme runup is derived from the measurements of pressure sensors deployed in the intertidal zone. Deep water wave parameters are used to force a high-resolution wave model, and nearshore wave parameters and high-resolution topographic data are analyzed concurrently with runup time series in order to assess the dependence of the runup on hydrodynamic conditions and morphological parameters. The wave runup is shown to be strongly related to the square root of the offshore significant wave height times the offshore wavelength. The measurements also reveal the depth dependence of the runup, which is mainly attributed to the curvature of the foreshore profile. In comparison to empirical relation obtained for a mild-sloping beach, the present data show a significant reduction in normalized wave runup, that is attributed to enhanced bottom friction over the rocky bottom.
(Journal of Geophysical Research. Oceans. vol. 123, n° 2169-9275, pp. 7185-7205, 01/10/2018)
IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, MIO, IRD, AMU, INSU - CNRS, UTLN, CNRS, LOPS, IRD, IFREMER, INSU - CNRS, UBO EPE, CNRS, LETG, UNICAEN, NU, UA, EPHE, PSL, UBO EPE, UR2, CNRS, IGARUN, UN
Évaluation de l'état écologique des habitats benthiques en France métropolitaine. Rapport scientifique pour l'évaluation 2018 au titre des descripteurs 1 et 6 de la DCSMM (critères D6C4 et D6C5)
L’application d’un indicateur unique (BenthoVal) afin d’évaluer l’évolution de l’état des communautés benthiques au cours du dernier cycle d’évaluation (2012-2016) sur la base des données de macrofaune de substrats meubles acquises dans le cadre de la DCE, a permis de mettre en lien différentes pressions d’origine anthropique, intervenant dans un contexte local (identifiées à l’échelle de la station), avec la structure des communautés benthiques. Les résultats montrent des évolutions temporelles qui varient non seulement entre les différentes unités marines de rapportage et types d’habitats considérés, mais également au sein d’un même grand type d’habitat. Ceci montre l’importance du contexte local, à l’échelle stationnelle, tant au niveau des dynamiques temporelles propres à chaque habitat que des pressions qui s’y exercent. Ces résultats montrent également que les changements de la structure des communautés benthiques peuvent être associés à différentes échelles de temps, souvent imbriquées, que ce soit sous l’influence des perturbations d’origines anthropiques et/ou naturelles. Ceci affecte fortement notre compréhension des dynamiques associées ainsi que l’évaluation de l’état des habitats benthiques. Ces résultats montrent enfin en creux la nécessité de la mise en place d’une stratégie de suivi adaptée à l’utilisation de cet indicateur dans les futurs programmes de surveillance de la DCSMM.
(pp. 80 p. + annexes, 01/10/2018)
PatriNat, MNHN, CNRS, AFB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEMAR, IRD, IFREMER, UBO EPE, CNRS, ITEM, UP, CNRS, LILA, ENS-PSL, PSL