A Bayesian approach to estimate biodynamic model parameters: bioaccumulation of PCB 153 by the freshwater crustacean Gammarus fossarum
The first step to evaluate the effects of contamination on organisms is to study toxicokinetics. The bioaccumulation of contaminants by aquatic species is a variable phenomenon, since it depends on the characteristics of the environment, the properties of the contaminants and the species. Different toxicokinetic models have been developed to describe the accumulation of contaminants in aquatic food webs. In these models, the organism is often considered as a single compartment: the bioaccumulation is then described as the balance between uptake and elimination processes. The absorption process can involve both dissolved or trophic route. The diet of aquatic organisms is known to be an important route of bioaccumulation of contaminants. The elimination process includes excretion, metabolism and dilution by growth. To date, there are few models focusing on persistent organic contaminants. Furthermore, estimating models' parameters is generally done through a frequentist approach in two steps: first by estimating parameter(s) related to depuration and then estimating parameter(s) related to accucumulation. The problem by doing this is that depuration during the accumulation phase is neglected, while this process occurs in the two phases. The aim of our study is to propose a Bayesian framework to estimate the parameters of a biodynamic model together by considering simultaneously accumulation and depuration data. The posterior distribution obtained for all parameter will enable a more accurate assessment of bioaccumulation uncertainty. We illustrate our approach with the freshwater benthic invertebrate Gammarus fossarum exposed for 7 days to a sediment spiked with PCB153 and transferred to a clean media for 7 more days. The PCB153 concentrations in Gammarus fossarum increased from an initial concentration of 0.32 to 12.36 ng.g-1 ww (wet weight) at the end of accumulation step. When gammarids were transferred into a clean media, the PCB153 concentration in organisms decreased to 6.41 ng.g-1 ww at day 14. The bioaccumulation model assuming first-order kinetics was fitted to the data using Bayesian inference. The inference process quickly converged and thin posterior distributions were obtained for each parameter, meaning that data brough enough information to estimate preciselly each parameter. The median model predictions and their 95% credibility intervals showed a good fit of the model to the data.
(pp. 1, 20/06/2026)
IRSTEA, LBBE, UCBL, VAS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Seasonal variations of contamination and exoskeletal malformations in the white shrimps Palaemon longirostris in the Gironde estuary, France
Since the end of the 1980s, white shrimps (Palaemon longirostris) from the Gironde estuary have exhibited exoskeletal malformations, mainly involving cephalothorax, rostrum, scaphocerites and uropods. An 8-month study was carried out in 2015. Each month, 200 individuals were sampled and examined for exoskeletal malformations. Temporal variations in malformationfrequency were noted,particularlyduringthebreedingperiod, along withdecreases in the sizeof non-deformedshrimps related to the appearance of juveniles in breeding sites, and high mortality among deformed shrimps. A significant increase in proportions of deformed shrimp was observed, relating particularly to the size (and therefore the age) of individuals. No significant difference was found between shrimp proportions with different numbers of malformations (one to four) for a fixed size class, nor was there any variation in proportions within different size classes for a fixed number of malformations. This would appear toindicate thatthe number ofmalformations isacquiredand new malformations donot seemto appearduringthe lifecycle,exceptforthesmallest(youngest)shrimps.Themalformationspectrumshowednosignificantdifferencesbetweenthe biggest and smallest individuals for the different malformation associations, except for those involving cephalothorax, rostrum and uropods. This would suggest that some malformation associations lead to a higher mortality rate in shrimps subjected to them, due to greater impairment of feeding and/or swimming behaviour. Multiple component analysis of the different types of malformation showed correlations between exoskeletal pieces (rostrum and cephalothorax) and appendixes (scaphocerites and uropods). Regarding metal contamination in shrimp, no significant difference was highlighted between deformed and nondeformed shrimps. Organic pollutants were not measured in tissues. Certain herbicides such as metolachlore and chlortoluron.
(Environmental Science and Pollution Research. vol. 25, n° 0944-1344, pp. 22689-22701, 20/06/2026)
UR EABX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
First record of the invasive species Ianiropsis serricaudis Gurjanova, 1936 (Crustacea: Isopoda) in Arcachon Bay, Bay of Biscay (NE Atlantic)
The invasive isopod Ianiropsis serricaudis Gurjanova, 1936, originally described from the North-West Pacific Ocean, is herein reported for the first time on the French Atlantic coast. Its presence is probably due to oyster import activity, and the sampling of many brooding females in Arcachon Bay since 2013 suggests a well-established species. Its current European distribution is summarised and some morphological characters are discussed.
(BioInvasions Records. vol. 7, n° 2242-1300, pp. 171-176, 20/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Ingestion and contact with polyethylene microplastics does not cause acute toxicity on marine zooplankton
Toxicity of polyethylene microplastics (PE-MP) of size ranges similar to their natural food to zooplanktonic organisms representative of the main taxa present in marine plankton, including rotifers, copepods, bivalves, echinoderms and fish, was evaluated. Early life stages (ELS) were prioritized as testing models in order to maximize sensitivity. Treatments included particles spiked with benzophenone-3 (BP-3), a hydrophobic organic chemical used in cosmetics with direct input in coastal areas. Despite documented ingestion of both virgin and BP-3 spiked microplastics no acute toxicity was found at loads orders of magnitude above environmentally relevant concentrations on any of the invertebrate models. In fish tests some effects, including premature or reduced hatching, were observed after 12 d exposure at 10 mg L-1 of BP-3 spiked PE-MP. The results obtained do not support environmentally relevant risk of microplastics on marine zooplankton. Similar approaches testing more hydrophobic chemicals with higher acute toxicity are needed before these conclusions could be extended to other organic pollutants common in marine ecosystems. Therefore, the replacement of these polymers in consumer products must be carefully considered.
(Journal of Hazardous Materials. vol. 360, n° 0304-3894, pp. 452-460, 20/06/2026)
IEO | CSIC, CSIC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GABI, INRA, IFREMER, UMR MARBEC, IRD, IFREMER, UM, CNRS, CNR
Retrospective analysis of the ecological changes in the Laurentian ecosystem using sclerochronology
(20/06/2026)
MSSMat, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEMAR, IRD, IFREMER, UBO EPE, CNRS, UFR Santé [Poitiers], UP
Mission Baelo Claudia. Rapport d'activités
(20/06/2026)
LIENSs, INSU - CNRS, ULR, CNRS, HALMA, CNRS, MC, IRAA, UL2, AMU, CNRS, HeRMA [Poitiers], UP, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Les effets de la crue de juin 2016 sur la qualité de l'eau du bassin de la Seine
Page de couverture Le PIREN-Seine est un programme de recherche interdisciplinaire en environnement dont l'objectif est de développer une vision d'ensemble du fonctionnement du bassin versant de la Seine et de la société humaine qui l'investit, pour permettre une meilleure gestion qualitative et quantitative de la ressource en eau. Il est l’un des programmes composant la Zone Atelier Seine du CNRS. La cellule transfert des connaissances a pour but de valoriser les productions de savoirs scientifiques issues des recherches du PIREN-Seine, et de favoriser la mise à disposition de ces informations à un large public, des professionnels de la gestion de l’eau aux élus en passant par les usagers. Soutenue par l'Agence de l'eau Seine-Normandie et l'EPTB Seine Grands Lacs, et animée depuis octobre 2016 par l'association ARCEAU-IdF, cette cellule répond à une forte volonté de la part des chercheurs de participer au transfert des savoirs scientifiques et techniques vers la société civile. Elle est ainsi chargée de la rédaction et de l’édition de documents thématiques, de la mise en ligne de contenus scientifiques adaptés à la fois aux professionnels et au grand public, et de la mise en place d’ateliers de co-réflexion du programme. La collection des fascicules du PIREN-Seine analyse différents aspects du fonctionnement du bassin de la Seine, correspondant aux multiples domaines de recherche du programme. Ils s’adressent à tous les publics concernés par l’analyse et la gestion du bassin versant de la Seine et des problématiques environnementales et humaines qui y sont liées. Tous ces fascicules sont disponibles en téléchargement gratuit au format PDF sur le site du programme. Une première série de neuf fascicules a été publiée en 2009. En 2011, six nouveaux titres sont venus enrichir la collection. En 2017, la production des fascicules reprend avec une nouvelle collection, pour permettre aux acteurs du domaine de l’eau et de l’environnement de rester informés des dernières recherches scientifiques menées par le PIREN-Seine.
(pp. 70 p., 20/06/2026)
GEOSCIENCES, PSL, METIS, EPHE, PSL, INSU - CNRS, SU, CNRS, GIP-Seine-Aval, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEESU, ENPC, UPEC UP12, GEDI, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, LISIS, CNRS, INRAE
Late Holocene record from a Loire River incised paleovalley (French inner continental shelf): insights into regional and global forcing factors
(20/06/2026)
LPG-ANGERS, LPG, UA, UN UFR ST, UN, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, SHOM
Equilibrium modeling of the beach profile on a macrotidal embayed low tide terrace beach
Eleven-year long time series of monthly beach profile surveys and hourly incident wave conditions are analyzed for a macrotidal Low Tide Terrace beach. The lower intertidal zone of the beach has a pluriannual cycle, whereas the upper beach profile has a predominantly seasonal cycle. An equilibrium model is applied to study the variation of the contour elevation positions in the intertidal zone as a function of the wave energy, wave power, and water level. When forcing the model with wave energy, the predictive ability of the equilibrium model is around 60% in the upper intertidal zone but decreases to 40% in the lower intertidal zone. Using wave power increases the predictive ability up to 70% in both the upper and lower intertidal zones. However, changes around the inflection point are not well predicted. The equilibrium model is then extended to take into account the effects of the tide level. The initial results do not show an increase in the predictive capacity of the model, but do allow the model free parameters to represent more accurately the values expected in a macrotidal environment. This allows comparing the empirical model calibration in different tidal environment. The interpretation of the model free parameter variation across the intertidal zone highlights the behavior of the different zones along the intertidal beach profile. This contributes to a global interpretation of the four model parameters for beaches with different tidal ranges, and therefore to a global model applicable at a wide variety sites.
(Ocean Dynamics. vol. 68, n° 1616-7341, pp. 1207-1220, 20/06/2026)
LGO, UBS, IFREMER, UBO EPE, CNRS, LHSV, ENPC, EDF R&D, EDF [E.D.F.], Cerema Equipe-projet HA, Cerema, Cerema Equipe-projet HA, Cerema, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UBO EPE, LETG - Brest, LETG, UNICAEN, NU, UA, EPHE, PSL, UBO EPE, UR2, CNRS, IGARUN, UN
Qualité des Milieux Naturels
Qualité des Milieux Naturels
(pp. 96 p., 20/06/2026)
IC2MP [Poitiers], UP, INC-CNRS, CNRS, LIENSs, INSU - CNRS, ULR, CNRS, IPREM, UPPA, INC-CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IC2MP [Poitiers], UP, INC-CNRS, CNRS, P3F, INRA, ECOSYS, INRA