Etude de l’impact de la pollution sonore chez un invertébré marin, l’huître Magallana gigas : approches écophysiologique, écotoxicologique et éthologique au laboratoire et sur le terrain
Les activités humaines font peser sur l’écosystème marin de multiples pressions délétères. Pollution chimique, changement climatique, risque d’acidification, débris de plastique et déchets radioactifs ont des impacts sans précèdent. Une pollution de plus en plus reconnu comme majeur est la pollution sonore. La prospection sismique, le battage de pieux et le trafic maritime génèrent des niveaux sonores qui peuvent être extrêmement forts, modifiant fondamentalement le paysage acoustique sous-marin. On sait que de nombreux mammifères marins et poissons entendent le bruit généré par ces activités et que cela altère leur physiologie et leur éthologie. Par contre, chez les invertébrés marins très peu d’études avaient évalué leur capacité à entendre et l’impact de cette pollution sur eux reste à déterminer. Nous avons abordé le problème par une étude de la capacité de perception du son chez l'huître creuse Magallana gigas en utilisant une approche comportementale et physiologique. Nous avons montré que M. gigas entend dans la gamme de fréquences entre 10 et 1000 Hz. Cette analyse nous a permis de caractériser les sources de sons qui contribuent à leur environnement auditif. Au laboratoire, dans un milieu contaminé (i) au cadmium, un métal que nous avons considéré à la fois comme une substance toxique et un marqueur indirect de l'activité ventilatoire, et (ii), par des bruits de cargo, nous montrons un effet répresseur du bruit caractérisé par une diminution de l'activité valvaire, de l'activité ventilatoire et du taux de croissance. Nous rapportons également une diminution de la bioaccumulation du Cd dans les branchies et une modulation de l'expression de certains gènes. Nous avons enfin étudié sur un enregistrement de 2 ans dans le port commercial de Santander, le comportement (incluant les pontes et la croissance) de 3 groupes d’huitres exposés à une forte pollution sonore et à une « qualité de l’eau » considérée dans la littérature comme bonne à très bonne pour une masse d’eau fortement modifiée. Nous avons retrouvé dans notre analyse différents effets que nous avions provoqués ou prédits à partir du travail de laboratoire où nous avions manipulé le bruit seul. Nous concluons que la pollution sonore au sein du port doit diminuer le fitness des huîtres en modifiant leur activité valvaire, la hiérarchie de leurs rythmes biologiques et la croissance. Nos résultats suggèrent que la pollution sonore peut avoir des conséquences importantes sur les invertébrés et présente un risque fort en termes de productivité de l'écosystème.
(21/09/2018)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Deciphering long-term coastal dynamics using IR-RF and ESR dating: a case study from Médoc, south-west France
A proper understanding of local palaeoenvironmental histories is an iterative process. Previously settled inter- pretations suddenly demand a reconsideration triggered by findings from sites not accessible before. The coastline of the Médoc area in south-west France faced considerable recent erosion, providing new valuable insights into the history of the local Holocene and Pleistocene deposits; mainly of estuarine, lacustrine and aeolian origin. In the framework of the project LITAQ for reconstructing the coastal history of the Aquitaine basin, new recently outcropped sediment profiles have been investigated. To establish the chronological fra- mework, for the first time optically stimulated luminescence (OSL) on quartz, infrared radiofluorescence (IR-RF) on K-feldspar were applied in conjunction with multiple-centres electron spin resonance (ESR) dating on quartz. Our approach combines routine luminescence dating application with methodological investigations, with a focus on IR-RF and ESR dating. IR-RF and ESR ages are consistently older than the OSL ages, presumably due to insufficient bleaching, however, they are consistent within 2σ. Our study confirms that the investigated area is covered by Holocene sands, following Pleistocene colluvial and aeolian sandy deposits mainly deposited in a periglacial context during MIS 8 and MIS 10. The base of the profiles appears to consist of interglacial estuarine deposits, probably from the Holsteinian (MIS 11), supporting the theory of a progressive replacement of a tide- influenced marsh by a peaty fresh-water pond during that period. Finally, IR-RF and multiple-centres ESR dating can be considered as valuable tools to decipher Middle Pleistocene landscape dynamics.
(Quaternary Geochronology. vol. 48, n° 1871-1014, pp. 108 - 120, 17/09/2018)
IRAMAT-CRP2A, IRAMAT, UTBM, UO, UBM, CNRS, Inrap, PACEA, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UBM, CNRS
Temperature modulates fatty acids profiles in freshwater diatoms and the impact of herbicides
Fatty acids are essential elements for the structure of biological membranes and for the storage of metabolic energy. They are used as a source of energy by metabolism at each trophic level, making fatty acids biochemically and physiologically important compounds (Neves et al. 2015). In the trophic chain, many fatty acids are only synthesized by microalgae and bacteria before being transferred via herbivorous invertebrates to fish and ultimately to humans (Arts et al. 2001). For example, highly unsaturated fatty acids (HUFA) such as eicosapentaenoic acid (EPA; C20:5n3), cannot be synthesized de novo or in insufficient proportions by animals (Saito and Aono 2014). That is why fatty acid analysis is commonly used to study trophic interactions in food chains. Generally, microalgae with a high proportion of EPA, such as diatoms, are an excellent source of food for animals but the concentrations of these different fatty acids can vary according to different environmental parameters including temperature, and may be affected by pesticide exposure (Brett et al. 2006, Robert et al. 2007, Burns et al. 2011, Li et al. 2014, Filimonova et al. 2016). The aim of this study is to investigate the impact of two herbicides combined to a 3°C-temperature increase on diatom's fatty acids and photosynthesis. To address this issue, two model freshwater diatoms (Gomphonema gracile and Nitzschia palea) were exposed to two herbicides, with two different cellular targets, at high concentration (diuron and s-metolachlor, C=10 µg/L) and two temperatures (T1=17,5 °C and T2=20,5°C). After a 1-week exposure, the analysis of photosynthesis was carried out by PhytoPAM measurements, and fatty acid composition of diatom cultures was determined by gas chromatography. For the control samples, the photosynthesis increased with the temperature for the both species mainly for Gomphonema gracile. Concerning the fatty acids composition of the both species, saturated and monounsaturated fatty acids decreased with temperature while polyunsaturated fatty acids increased. The 3°C increase in temperature enhanced the toxicity of diuron towards the photosynthesis of both species, while it reduced the effect of S-metolachlor for Gomphonema gracile. Fatty acids analysis are still ongoing. Our results highlight contrasting effects of a moderate increase of temperature on the toxicity of pesticides towards diatoms, at the physiological (photosynthesis) and structural (fatty acid content) levels.
(pp. 1, 11/09/2018)
UR EABX, IRSTEA, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Flash Rip Statistics from Video Images
(Journal of Coastal Research. vol. 81, n° 0749-0208, pp. 100-106, 03/09/2018)
LGO, UBS, IFREMER, UBO EPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ECOLA, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS
Controls on Flash Rip Current Hazard on Low-Tide Terraced Tropical Beaches in West Africa
(Journal of Coastal Research. vol. 81, n° 0749-0208, pp. 92, 03/09/2018)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LGO, UBS, IFREMER, UBO EPE, CNRS
Use of Specific Primary and Secondary Organic Markers for PM Source Apportionment Based on Positive Matrix Factorization (PMF)
(02/09/2018)
LCME, USMB [Université de Savoie] [Université de Chambéry], LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, INERIS
Assessment of the toxicity and the fertilizing power from application of gamma irradiated anaerobic sludge as fertilizer: Effect on Vicia faba growth
With increasing sludge produced every day by wastewater treatment plants, new methodologies have been developed to reduce sludge or to valorize them at lower cost and energy. Among these methodologies, agricultural manuring is of great interest as sludge could complement or replace chemical fertilizers. However, sludge pretreatment was necessary prior to its use in order to eliminate the degradable organic contaminants, heavy metals and diverse pathogenic microorganisms. In this study we performed γ-irradiation of anaerobic sludge coming from wastewater treatment plants at different doses (0.5, 1.5, 2.5, 3.5 and 4.5 kGy), followed by anaerobic digestion. We then used them in addition to soil for Vicia faba cultures. Heavy metal concentrations, toxicological evaluations, and the number of cultivable pathogenic bacteria were also investigated in irradiated and non-irradiated sludge samples to determine the effect of γ-irradiation on toxicity and pathogens present in the sludge. Results show that 4.5 kGy is the optimal dose, and γ-irradiation pretreatment of anaerobic sludge added to soil (2 mL/30 g) has significantly improved Vicia faba growth. Furthermore, by eliminating pathogens and by degrading chemical pollutants, γ-irradiation of anaerobic sludge provides promising insights for re-using sludge as a safe fertilizer.
(Radiation Physics and Chemistry. vol. 150, n° 0969-806X, pp. 163-168, 01/09/2018)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Experimental calibration of manganese incorporation in foraminiferal calcite
(Geochimica et Cosmochimica Acta. vol. 237, n° 0016-7037, pp. 49-64, 01/09/2018)
BIAF, UA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LPG-ANGERS, LPG, UA, UN UFR ST, UN, INSU - CNRS, CNRS, LPG, UA, UN UFR ST, UN, INSU - CNRS, CNRS
Evaluation of psychiatric hospital wastewater toxicity: what is its impact on aquatic organisms?
The primary source of pharmaceuticals to the aquatic environment is the discharge of wastewater effluents. Pharmaceuticals are a large and diverse group of compounds. Among them, psychotropic substances are particularly interesting to study due to their specific known mode of action. The present study was performed to investigate the effects of wastewater effluents from a psychiatric hospital wastewater treatment plant (WWTP) on several aquatic organisms. All the analyzed pharmaceuticals (10 compounds) were detected in WWTP effluents as well as in the receiving river. Although the environmental concentrations were generally at trace levels (ng L-1 to μg L-1), induce toxic effects were observed. This study showed the effects of the WWTP effluents on the oogenesis and/or embryogenesis of amphipod crustacean Gammarus fossarum, Japanese fish medaka Oryzias latipes, mollusk Radix peregra, and planarian Schmidtea polychroa. A decrease of the number of oocytes and produced embryos was observed for G. fossarum and S. polychroa. Similarly, the hatching rate of R. peregra was affected by effluents. In the receiving river, the macroinvertebrate community was affected by the wastewater effluents discharge.
(Environmental Science and Pollution Research. vol. 25, n° 0944-1344, pp. 26090-26102, 01/09/2018)
BTSB, INUC, Comue de Toulouse, LPTC, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR MALY, IRSTEA, UNS, CHU Nice, UniCA, LCE, CNRS, UFC, UBFC, GEODE, UT2J, Comue de Toulouse, CNRS
The impacts of oceanic deep temperature perturbations in the North Atlantic on decadal climate variability and predictability
Decadal climate predictability in the North Atlantic is largely related to ocean low frequency variability, whose sensitivity to initial conditions is not very well understood. Recently, three-dimensional oceanic temperature anomalies optimally perturbing the North Atlantic Mean Temperature (NAMT) have been computed via an optimization procedure using a linear adjoint to a realistic ocean general circulation model. The spatial pattern of the identified perturbations, localized in the North Atlantic, has the largest magnitude between 1000 and 4000 m depth. In the present study, the impacts of these perturbations on NAMT, on the Atlantic meridional overturning circulation (AMOC), and on climate in general are investigated in a global coupled model that uses the same ocean model as was used to compute the three-dimensional optimal perturbations. In the coupled model, these perturbations induce AMOC and NAMT anomalies peaking after 5 and 10 years, respectively, generally consistent with the ocean-only linear predictions. To further understand their impact, their magnitude was varied in a broad range. For initial perturbations with a magnitude comparable to the internal variability of the coupled model, the model response exhibits a strong signature in sea surface temperature and precipitation over North America and the Sahel region. The existence and impacts of these ocean perturbations have important implications for decadal prediction: they can be seen either as a source of predictability or uncertainty, depending on whether the current observing system can detect them or not. In fact, comparing the magnitude of the imposed perturbations with the uncertainty of available ocean observations such as Argo data or ocean state estimates suggests that only the largest perturbations used in this study could be detectable. This highlights the importance for decadal climate prediction of accurate ocean density initialisation in the North Atlantic at intermediate and greater depths.
(Climate Dynamics. vol. 51, n° 0930-7575, pp. 2341 - 2357, 01/09/2018)
PARVATI, LOCEAN, IPSL, ENS-PSL, UVSQ, UPMC, CEA, INSU - CNRS, X, CNES, CNRS, MNHN, IRD, UPMC, INSU - CNRS, CNRS, NOC, NOC, LOCEAN-VARCLIM, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, UVSQ, CEA, INSU - CNRS, X, CNES, SU, CNRS, UPCité, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, PSL, UVSQ, CEA, INSU - CNRS, X, IP Paris, CNES, SU, CNRS, UPCité, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS