Effets de mélanges environnementalement réalistes de pesticides sur des biofilms naturels ayant des historiques d'exposition différents
Localisée dans la région viticole du Beaujolais (Est de la France), la Morcille est soumise à une pression viticole forte conduisant à la contamination de la rivière par une gamme d'herbicides et de fongicides. L'objectif de cette étude est d'utiliser des extraits d'échantillonneurs passifs pour mettre en évidence les effets de mélanges réalistes de pesticides sur des biofilms naturels avec des antécédents d'exposition diversifiés. Les impacts chroniques et aigus des pesticides en mélange sur les biofilms ont été évalués à l'aide d'extraits de POCIS (Polar Organic Chemical Integrative Samplers) préalablement immergés à l'aval du cours d'eau (site le plus contaminé). Leurs effets sur des communautés issues de l'amont (site de référence) et de l'aval (contaminé) ont été étudiés en canaux artificiels, dans lesquels les biofilms ont été placés dans des conditions non contaminées pendant 13 jours, ou exposés à des extraits de POCIS afin de reproduire une pression toxique réaliste (observée in situ). Après 13 jours d'exposition, des impacts significatifs de la contamination ont été observés sur les paramètres liés à la biomasse, à la croissance et à la physiologie des biofilms. Une diminution significative de la densité de diatomées a été observée pour les biofilms exposés, par rapport aux témoins, quelle que soit l'origine du biofilm. Les analyses taxonomiques ont révélé des impacts des mélange de pesticides sur la composition des diatomées, la structure des communautés amont divergeant avec l'exposition ou non (avec des abondances accrues de Nitzschia palea et Eolimna minima pour la modalité contaminée). Les communautés aval, exposées ou non, se sont avérées présenter une composition, soulignant l'importance des processus d'immigration dans la récupération des assemblages de diatomées. Afin d'évaluer la tolérance initiale de biofilms au mélange de pesticides, des tests de toxicité aiguë ont été réalisés en début d'expérience, révélant une tolérance nettement plus élevée des biofilms originaires du site en aval, par rapport aux biofilms amont. Cette différence de tolérance aux extraits d'échantillonneurs passifs peut s'expliquer par les compositions taxonomiques très différentes selon l'origine du biofilm, elle reflète l'adaptation des communautés par les processus de sélection des espèces et illustre le concept PICT (Blanck et al, 1988.). Nos résultats soulignent des effets des mélange de pesticides marqués sur la croissance du biofilm, la composition diatomique, et sur la tolérance des biofilms naturels aux facteurs auxquels ils sont exposés. Cette étude met en évidence l'utilisation potentielle des extraits d'échantillonneurs passifs, combinés avec des tests de toxicité aiguë, pour l'expérimentation des impacts d'expositions chroniques plus réalistes sur les biofilms naturels, et offre des perspectives d'applications prometteuses pour l'évaluation du risque écologique lié aux pesticides.
(pp. 1, 19/04/2026)
UR REBX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR MALY, IRSTEA
Occurrence of selected micropollutants in treated wastewater and removal with optimised tertiary treatments
Two tertiary treatments were studied at pilot scale in three different plants. An advanced oxidation processes pilot was tested in two plants with two different upstream treatment processes: a membrane bioreactor and a low load activated sludge followed by a sand filter. An activated carbon pilot was tested in one plant, a low load activated sludge followed by a sand filter and an ozone reactor. 64 micropollutants were analysed in the samples of this study. The tertiary treatments studied, ozone, AOP and activated carbon, were efficient for the removal of most of the micropollutants analysed in this study, except metals.
(pp. 3 p., 19/04/2026)
CIRSEE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR MALY, IRSTEA
Qualité de l’eau : chapitre 8.2
Etat de l'art concernant les grandes ressources naturelles de la région Aquitaine.
(pp. 249-264, 19/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR REBX, IRSTEA, UPMC
Flux dynamics of planktic foraminiferal tests in the south-eastern Bay of Biscay (northeast Atlantic margin)
The temporal and water depth related dynamics of planktic foraminiferal fluxes in the south-eastern Bay of Biscay are discussed for a two year sampling period (June 2006-June 2008). Two sediment traps deployed at 800 m and 1700 m water depth at a mooring in 2000 m of water depth, were analyzed for the flux of planktic foraminiferal species > 150 μm, in comparison with the total mass flux. Total flux of planktic foraminifera shows seasonal maxima in spring/early summer (> 2000 Ind. m− 2 d− 1) and minima from late summer through winter (< 10 Ind. m− 2 d− 1). The flux of planktic foraminiferal tests in the intermediate to deep water column at the inner Bay of Biscay comprises an intermittent and regionally variable signal of seasonal surface water primary productivity. Significant lateral transport and flux of particles superimposed on the downward mass flux indicate a decoupling of fluxes between the 800-m and 1700-m traps. The 210Pb budget and the presence of certain benthic foraminiferal species in the midwater column prove that the lateral flux originated from the upper continental slope. Despite the temporal and vertical variations of the particulate flux, a well-defined seasonal flux signal can be deduced from the frequency of planktic foraminiferal species.
(Journal of Marine Systems. vol. 109-110, n° 0924-7963, pp. S169-S181, 19/04/2026)
BIAF, UA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LPO, IRD, IFREMER, UBO EPE, CNRS
Globex: wave dynamics on a gently sloping laboratory beach
As waves approach the shore, non-linearity in their dynamics becomes increasingly important. Most of our understanding of wave non-linearity has resulted from theoretical work, laboratory experiments and field studies on beaches slopes steeper than about 1:40. Here, very strong non-linear processes happen locally and on a short time scale, as demonstrated by narrow surf zones with plunging or collapsing breakers. The non-linearity on lower sloping beaches, typical of high-energy dissipative environments, has a different character, as it can now build up over a long period of time in a cross-shore extensive area. This second case of strong non-linearity is not well understood. This contribution serves to introduce the GLOBEX project, during which a high-resolution (in space and time) data set of the cross-shore evolution of short and infragravity waves was collected on a low-sloping (1:80) non-mobile laboratory beach for a range of wave conditions. Various other presentations at the conference will build on this introductory contribution.
(pp. 1351 - 1362, 19/04/2026)
IMAU, LEGI, UJF, Grenoble INP, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, UC / UniCan, CESAM
Transient swash motions on a gently-sloping beach
Spectral and wavelet analyses are used to investigate run-up motion on a gently sloping beach with special attention devoted to the coupling between the long-period swash oscillations and the wave grouping outside the surf zone. Runup elevations were measured under random-wave conditions during the laboratory GLOBEX experiments carried out along a 1:80 sloping, fixed beach. A capacitance wire was deployed parallel to the bottom in order to detect the swash edge. The low Iribarren numbers involved in the experiments led to swash motions dominated by surf beat. High correlation levels between the scale-averaged wavelet power and the run-up suggest that low-frequency swash motions are still associated with the modulation of offshore swell waves. In addition, wavelet analysis supports the idea that swash-swash interactions are important in controlling swash oscillations.
(pp. 1385 - 1396, 19/04/2026)
UC / UniCan, LEGI, UJF, Grenoble INP, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Numerical modelling of equilibrium and evolving lightweight sediment laboratory beach profiles
The recent advances of numerical beach profile models allowed the simulation of on/offshore sandbar migrations on timescales of weeks to months with fair success. These models were systematically applied to natural, persistently evolving, beaches. In this contribution, we apply our model to small-scale laboratory experiments for which coarse and lightweight sediment is used to satisfy the laws of similitude in the flume. Such experiments can result in equilibrium beach profiles and provide detailed information on the respective role of undertow and wave nonlinearities on sediment transport and the resulting cross-shore sandbar migration. Here we first apply the coupled, wave-averaged, cross-shore waves-currents-bathymetric evolution model 1DBeach to an equilibrium beach profile. The model simulates an equilibrium beach profile with reasonable success. Yet, when applying the best fit parameters to a subsequent rapid onshore sandbar migration, the model fails in reproducing the overall beach profile evolution. Further model calibration on the evolving beach profile sequence shows that the model can actually reproduce the rapid onshore sandbar migration with a significant contribution of acceleration skewness. This suggests that a number of misspecifications of the physics remain in coupled, wave-averaged, cross-shore waves-currents-bathymetric evolution model. In addition, given that best-fit model free parameters are of the same order of magnitude of those found on natural beaches, our study suggests that small-scale experiments with coarse and lightweight sediment can be used to further explore the respective contribution of wave nonlinearities and undertow to sediment transport and the overall beach profile evolution.
(pp. 521 - 530, 19/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEGI, UJF, Grenoble INP, CNRS, DYNECO, IFREMER, IMAU
Contamination et physiologie des poissons exposés à des polluants
(19/04/2026)
LPGP, INRA, Biosit : Biologie - Santé - Innovation Technologique, IFREMER, UB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UB, ULR, LIENSs, INSU - CNRS, ULR, CNRS, ULH, NU, BGMCD, IP, CNRS, PAnTher, ONIRIS, INRAE
Variation patterns in individual fish responses to chemical stress among estuaries, seasons and genders: the case of the European flounder (Platichthys flesus) in the Bay of Biscay
The objective was to describe and model varia- tion patterns in individual fish responses to contaminants among estuaries, season and gender. Two hundred twenty- seven adult European flounders were collected in two sea- sons (winter and summer) in four estuaries along the Bay of Biscay (South West France), focusing on a pristine system (the Ster), vs. three estuaries displaying contrasted levels of contaminants (the Vilaine, Loire and Gironde). Twenty-three variables were measured by fish, considering the load of contaminants (liver metals, liver and muscle persistent organic pollutants, muscle polycyclic aromatic hydrocar- bons); the gene expression (Cyt C oxydase, ATPase, BHMT, Cyt P450 1A1, ferritin); the blood genotoxicity (Comet test); and liver histology (foci of cellular alteration-tumour, steatosis, inflammation, abnormal glycogen storage). Ca- nonical redundancy analysis (RDA) was used to model these variables using gender, season and estuary of origin as explanatory variables. The results underlined the homo- geneity of fish responses within the pristine site (Ster) and more important seasonal variability within the three contam- inated systems. The complete model RDA was significant and explained 35 % of total variance. Estuary and season respectively explained 30 and 5 % of the total independent variation components, whilst gender was not a significant factor. The first axis of the RDA explains nearly 27 % of the total variance and mostly represents a gradient of contami- nation. The links between the load of contaminants, the expression of several genes and the biomarkers were ana- lysed considering different levels of chemical stress and a possible multi-stress, particularly in the Vilaine estuary.
(Environmental Science and Pollution Research. vol. 20, n° 0944-1344, pp. 738-48, 19/04/2026)
LEMAR, IRD, IFREMER, UBO EPE, CNRS, LEHNA IPE, LEHNA, UCBL, ENTPE, CNRS, Cedre, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, PAnTher, ONIRIS, INRAE
Responses of juvenile European flounder (Platichthys flesus) to multistress in the Vilaine estuary, during a 6-month survey
Physiological and genetic responses of age 0+ Platichthys flesus were investigated in the eutrophicated and moderately contaminated Vilaine estuary, during a 6-month survey. The main objective of this study was to explore the biological responses of fishes during their juvenile period in an estuarine system in order to detect a possible selective pressure induced by the environmental stress. Our results showed a general convergence in physiological responses along the survey: an increase in genotoxicity was associated with an increase in mRNA expression of ATPase and betaine homocysteine methyltransferase. These results could suggest an increase of cellular damage, energetic request, and detoxification rate related to the growing exposure time to stress. Considering the aging of the cohort, the genetic characteristics of the Vilaine flounder cohort came closer to the one observed in a highly stressed system, the Seine estuary, suggesting a potential selective pressure mainly induced by the chemical stress.
(Environmental Science and Pollution Research. vol. 20, n° 0944-1344, pp. 676-689, 19/04/2026)
Cedre, LEHNA IPE, LEHNA, UCBL, ENTPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GU, LEMAR, IRD, IFREMER, UBO EPE, CNRS