Investigation of the combined influence of salinity and particle concentration on the adsorption of anionic and zwitterionic PFAS onto estuarine sediment using the RSM modelling approach
Salinity (S) and suspended particulate matter (SPM) are key factors influencing the sorption of micropollutants in estuaries, due to strong gradients in these ecosystems. Previous laboratory or field-based studies have typically investigated the impact of S or SPM separately. Thus, the combined effects of S and SPM as well as their interactions on the sorption of micropollutants such as per- and polyfluoroalkyl substances (PFAS) in estuarine environments still remain poorly understood. We initially investigated the adsorption kinetics of 11 anionic and zwitterionic PFAS onto estuarine sediment under one S/SPM combination in laboratory-controlled conditions, as well as their adsorption isotherms under two S/SPM combinations. We also determined their distribution coefficients (K d ) across 35 S/SPM combinations covering a wide range of estuarine conditions. The adsorption kinetics of PFAS could be described by a pseudo-second-order model (equilibrium time <24h). Sorption isotherms were fitted by both linear and Freundlich models; the linear sorption range was in the range 0.12–1.31 nM and K d varied between 0.6 and 55271 L/kg. Based on response surface modelling, both S and SPM were significant factors, i.e. K d was positively related to S (salting-out effect), while it was negatively related to SPM concentration (third-phase effect). SPM had a stronger effect than S for short-chain carboxylates, whereas S was the dominant factor for most other compounds. We also present, for the first time, evidence of a significant negative interaction between these two factors. This study therefore provides a new perspective to model the fate of PFAS at the land-sea interface.
(Peer Community Journal. vol. 5, n° 2804-3871, pp. e124, 12/11/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
The ongoing spread of the Asian date mussel (Arcuatula senhousia) within the French Atlantic coast: colonisation dynamics and associated drivers in a historically invaded ecosystem (Arcachon Bay)
Arcuatula senhousia is a non-indigenous species first observed in Arcachon Bay in 2002. At that time, the species’ distribution was restricted to the northern part of this coastal lagoon. During the following 7–8 years, the species also started to colonise its south-eastern parts. Then, two surveys conducted in 2018 and 2021 showed that the species was observed over most of the investigated tidal flats within the lagoon. Between those two periods, there was a threefold increase in both frequencies of occurrence and average densities. The highest average densities and frequencies were observed in areas colonised in 2002. It suggests that this area is either the main area of introduction/settlement for the species or the area where it could find the most suitable ecological conditions. However, the use of Species Distribution Modelling showed that, considering habitat features, most of the intertidal flats in Arcachon Bay were a highly suitable habitat for A. senhousia . Further colonisation of the lagoon during the coming years appears very likely. The study of its habitat in this area suggested that the presence of meadows favoured the settlement of A. senhousia individuals. Furthermore, lower bottom current velocity and the erosion potential it induces seemed to be the principal environmental factors driving the distribution pattern of this species within the bay. However, other factors that could regulate the spread of A. senhousia must be considered. Understanding the dynamics of A. senhousia colonisation and identifying its drivers aimed to characterise possible areas to be colonised by this species. This is a crucial point in determining how to manage its distribution and assess the risk of spreading within other ecosystems.
(Aquatic Invasions. vol. 20, n° 1798-6540, pp. 427-450, 12/11/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, PatriNat, MNHN, IRD, CNRS, OFB - DSUED, OFB, LERAR, COAST, IFREMER
Deep learning for carbonate rocks petrography
This project aims to investigate deep learning capacity to enhance the identification of factors that may impact the dynamic behavior of carbonate reservoirs. This is achieved through the integration of comprehensive datasets comprising images acquired over decades from hydrocarbon carbonate reservoirs and identified outcrop analogues. Convolutional neural networks represent natural candidates for analyzing the thousands of available thin sections. This thesis developed a suite of complementary methods for their quantitative and automated description. An optimal subdivision strategy for high-resolution images was established to enable multi-scale characterization of this data type, closely approximating traditional microscopic analysis methods. The approach combines representation learning through a rotation-invariant variational autoencoder with automatic clustering, achieving a two-fold acceleration in labeling time while forming geologically coherent groups based primarily on R. Dunham's classifications for limestones, R. Folk's classifications for dolomites, and the incorporation of secondary minerals such as anhydrite facies. The model can then be refined for these subsidiary classification tasks, enabling semantic description of the samples studied (>88% mAP). To address the heterogeneity of existing petrographic descriptions and the lack of precise quantification on real data, two methods were developed: SynSection procedurally generates training data by simulating depositional processes (+20% mAP) in grain limestones, while SynSection2 unifies synthetic-to-realistic transformation with segmentation (+5% additional mAP). These approaches jointly enable automatic segmentation of elements (bioclasts, intraclasts, ooids, and peloids) and the creation of a homogeneous quantified database. Deep semantic segmentation applied to granular limestones provides access to quantification of relative proportions and grain size distribution analysis. The developed metrics achieve determination coefficients (R²) of 0.78 for mean grain size and 0.72 for sorting. This integrated methodology enables standardized and reproducible description following established petrographic nomenclatures and can be superimposed on pore network analysis. Automated quantification of pore types reveals heterogeneities that facilitate comparative analysis between samples. This approach constitutes a powerful tool for quantitative petrographic analysis, capable of incorporating local refinements to fully exploit deep learning's potential in characterizing carbonate systems and understanding associated petrophysical responses.
(10/11/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Rising atmospheric CO2 concentrations
Across the last deglaciation, the atmospheric CO 2 concentration (CO 2 ) increased substantially from ∼ 180 to ∼ 280 ppm, yet its impact on vegetation dynamics across this major climatic transition remains insufficiently understood. In particular, Iberian pollen records reveal an intriguing feature that can be related to an often overlooked role of CO 2 in shaping vegetation responses during the last deglaciation. These records reveal the near disappearance of forests during the cold Last Glacial Maximum (LGM) and Heinrich Stadial 1 (HS1) phases and an unexpected recovery during the Younger Dryas (YD) cold phase when CO 2 increased. Here, we present high-resolution tracers of terrestrial (pollen, C 29 : C 31 organic biomarker) and marine (alkenone-derived Sea Surface Temperature, C 37 : 4 %, and long-chain n-alkanes ratios) conditions from the southwestern (SW) Iberian margin Integrated Ocean Drilling Program Site U1385 ("Shackleton site") for the last 22 cal kyr BP. This direct land-sea comparison approach allows us to investigate how the Iberian Peninsula vegetation responded to major global CO 2 changes during the last deglaciation.
Our results show that cool and moderately humid conditions of the LGM supported a grassland-heathland mosaic ecosystem, but low CO 2 likely caused physiological drought and suppressed forest development. HS1, the coldest and most arid period, combined with sustained low CO 2 values, almost suppressed forest growth in favour of Mediterranean steppe. In contrast, the warmer Bølling-Allerød, characterised by a temperature optimum and variable but generally wetter conditions, along with the rise of CO 2 above 225 ppm at ∼ 15 cal kyr BP, contributed to substantial forest development. During the YD, sufficient moisture combined with increasing CO 2 enabled the persistence of a mixed grassland-forest mosaic despite cooler temperatures. Our study suggests that during cool and humid periods (LGM and YD) different pCO 2 values led to contrasting SW Iberian vegetation responses. In contrast, during periods of relatively high CO 2 , temperature and precipitation played the main role in shaping the distribution and composition of the vegetation.
(Biogeosciences. vol. 22, n° 1726-4170, pp. 6631 - 6650, 07/11/2025)
IPMA, CCMAR, UAlg, CCMAR, UAlg, CIMAR/CCMAR, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
It’s about time: integrating micro- and macro-evolutionary perspectives into ecotoxicology for improved predictions and long-term assessment of ecosystem health
Whilst ecology has served as a foundational inspiration for risk assessment in ecotoxicology, far less attention has been given to evolution, despite its importance. As the need for a new paradigm in ecotoxicology is becoming increasingly evident in the face of Global change, the consideration of evolutionary processes and patterns should provide a way to progress towards this objective. This review draws on the recent literature to feed this idea, with a particular attention to the interplay between evolutionary paces. Doing so, we recast ecotoxicology as an innovative, exciting discipline, conceptually equipped to meet the challenges of the Anthropocene era.
(Current Opinion in Environmental Science & Health. vol. 48, pp. 100688, 01/11/2025)
LIENSs, INSU - CNRS, ULR, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, DECOD, IFREMER, INRAE, Institut Agro, Institut Agro
Combined Atmospheric and Marine Heatwaves Exacerbate the Impacts of a Non-Indigenous Species, the Asian Date Mussel Arcuatula Senhousia, on Benthic Ecosystem Functioning
Climate change is predicted to increase the frequency, severity, and duration of extreme climatic events such as heatwaves. Benthic organisms inhabiting intertidal flats are subjected to both marine and atmospheric heatwaves and can experience extreme temperature variations over relatively short periods of time. Non-indigenous species are generally capable to cope with extreme events more efficiently that native species. The Arcachon bay, a lagoon located along the French Atlantic coast is currently colonised by the invasive mussel, Arcuatula senhousia. In this study, we investigated how these two stressors (non-indigenous species colonisation and heatwaves) affect soft-bottom ecosystem functioning. We conducted two seasonal laboratory experiments to investigate the effects of combined marine and atmospheric heatwaves on the biogeochemical dynamics of sediments colonised by A. senhousia at different densities. More precisely, we assessed the community scale responses by measuring nutrients (NOx, NH4+, PO43-) and oxygen fluxes across the sediment-water interface. The results highlight that (1) heatwaves affect oxygen and nutrient exchanges across the sediment-water interface, (2) the magnitude of these effects can be strongly enhanced by increasing densities of A. senhousia, and (3) a marked seasonal-dependence. These results emphasise that the interaction between the seasonality of heatwave occurrence, its intensity and the level of colonisation by non-indigenous ecosystem engineers likely shape their consequences for ecosystem functioning. Our results thus reinforce previous findings suggesting that climate change may profoundly exacerbate the effects of biological invasions.
(Marine Environmental Research. vol. 212, n° 0141-1136, pp. 107560, 01/11/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, PatriNat, MNHN, IRD, CNRS, OFB - DSUED, OFB, LERAR, COAST, IFREMER
Confounding factors affect hemocyte responses of mussels Mytilus galloprovincialis upon foodborne exposure to polystyrene nanoplastics of three sizes
Information regarding the impact of nanoplastics (NPs, ≤ 1 μm) on marine organisms is insufficient. This work aimed to investigate the differential toxicity of three sizes of polystyrene (PS) NPs (50, 200 and 1000 nm) on the hemocytes and condition index (CI) of sentinel marine mussels Mytilus galloprovincialis. Mussels were dietarily exposed for 7 days through microalgae to PS at a low dose (LD: 103 NPs/mL) and a high dose (HD: 108 NPs/mL of 50 and 200 nm NPs, and 106 NPs/mL of 1000 nm NPs). Each experiment (E) was performed twice, as follows: E1 and E4 for 50 nm PS NPs, E2 and E5 for 200 nm PS NPs and E3 and E6 for 1000 nm PS NPs. Despite the six experiments were run in less than a month, there were significant differences between the independent experiments of the different sizes of PS NPs. No differences in CI were found within each experiment, but differences were observed between independent experiments, possibly due to the spawning events observed during the acclimation of mussels of E3-E4. Similarly, a higher ROS production occurred in hemocytes of control mussels of E3-E4 compared to E1-E2 and E5-E6. But no differences in ROS were recorded in NPs treatments compared to controls within experiments. Cell viability of control hemocytes decreased in E3-E4 and E5-E6 in comparison to E1-E2. This could mask the size-dependent response to the NPs, as in E1 hemocytes showed lower viability and phagocytic activity than those from control mussels, but not in E4. Similarly, hemocytes of mussels exposed to HD in E2 showed lower viability than controls, but the contrary was observed in E5. In conclusion, a trend for size-dependent effects on mussel hemocytes was observed. However, hemocyte responses varied along time, possibly due to seasonal variations in mussels physiology connected with the gametogenic cycle.
(Science of the Total Environment. vol. 1003, n° 0048-9697, 01/11/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UB, UPV / EHU
New mammal assemblage from last interglacial in Argentine Pampas: Debating biostratigraphic and biochronological reliability
This study analyzes one of the most complete mammalian fossil records from the Middle to the end of the Pleistocene in the Pampean Region, recovered from the Salto de Piedra Paleontological Locality along Tapalqué Creek. The site preserves a fluvial-palustrine sequence with six depositional units (U1-U6), separated by erosive unconformities or pedogenetic horizons. Radiometric dating (OSL and AMS 14 C), integrated with sedimentological and faunal data, allows correlation with Marine Isotope Stages: Unit 1 (MIS 6-5; >127 ka), Unit 2 (MIS 3; ~40.5 ka), Units 3-4 (MIS 2; 38-11.2 ka), and Units 5-6 (MIS 1; 12.6-7.8 ka). Three fossil assemblages were identified (U1, U3-4, U5-6), primarily linked to fluvial channels. The record provides critical biochronological information, with fossils showing minimal weathering and abrasion, and no evidence of reworking. The occurrence of Equus neogeus in U1 (>127 ka) expands the lower limit of its biozone back to ~300 ka. Index taxa in Unit 1-Glyptodon munizi, Megatherium americanum, Equus neogeus-highlight biozone overlap, challenging the stratigraphic resolution of traditional schemes. Due to the lack of exclusive taxa and overlapping ages, we propose merging the Bonaerean with the Lujanian Stage/Age (~300-11.6 ka). These findings call for a revision of Quaternary biozone frameworks in South America and improve biostratigraphic resolution for the Pampean fossil record.
(Quaternary Science Reviews. vol. 367, n° 0277-3791, 01/11/2025)
UV, MNCN, CSIC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CRILAR, UR, UC3M
Epigenetic regulation of sex: the role of DNA methylation and zbtb38 in zebrafish sex differentiation and heat-induced masculinization
There is increasing evidence that global change can threaten biodiversity by inducing skewed sex ratios. Accumulating evidences support a role of epigenetics, mainly DNA methylation, in sex differentiation. The aim of the present work was to investigate the potential role of zbtb38, a transcriptional factor that binds to methylated promoters, in sex differentiation and/or maintenance in zebrafish. We analyzed the methylation and transcription level of zbtb38 in males, females and undifferentiated individuals raised at standard or high temperature, a masculinizing factor. Results were compared to those obtained for genes already known to be involved in sex differentiation/maintenance (cyp19a1a, foxl2a, dmrt1). All genes presented a sex-specific pattern of DNA methylation and transcription but the most significant differences between sexes were observed for zbtb38. Moreover, a highly significant positive correlation was observed between the methylation level of zbtb38 and cyp19a1a, which encodes an enzyme that converts androgens into estradiol. However, while the hypermethylation of cyp19a1a was associated with its down-regulation, an inverse relationship was observed for zbtb38, providing a basis for mutual antagonism. Furthermore, zbtb38 was the only gene for which its transcription level was affected by temperature, being up-regulated in females that escaped to masculinization. Finally, despite embryos presented a paternal methylome, zbtb38 was the only gene for which its methylation level rapidly changed during early development to reach intermediate values between males and females at the larval stage, ie a bi-potential state. Our results strongly support a strategic role of DNA methylation and zbtb38 in sex differentiation and maintenance.
(Molecular and Cellular Endocrinology. vol. 609, n° 0303-7207, pp. 112636, 01/11/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Métabolisme dans les eaux du bassin de la Seine au regard de la matière organique
Au delà des aspects climatiques et malgré un rôle clé dans les processus environnementaux, la composition et la réactivité de la matière organique (MO) sont encore mal comprises. Il est notamment essentiel d’améliorer les connaissances sur les propriétés physico-chimiques des différentes formes de la MO. En effet, non seulement la quantité de carbone organique dissous , mais aussi et surtout sa qualité, reflètent l’interaction dynamique entre les sources de MO et les processus biogéochimiques et sont susceptibles d’avoir des répercussions écologiques. Comprendre ces dynamiques du carbone est indispensable pour la modélisation de la qualité de l’eau le long du continuum aquatique des cours d’eau incluant d’autres compartiments, tels que les lacs et réservoirs, les zones humides et les interfaces nappe-rivière. Le présent fascicule fait ainsi état des travaux menés par le PIREN-Seine sur ce lien étroit entre métabolisme des rivières et matière organique, structuré autour des deux axes de la démarche scientifique du programme : observations (Chapitres 1 et 2) et modélisations (Chapitres 3 et 4).
(01/11/2025)
METIS, EPHE, PSL, INSU - CNRS, SU, CNRS, PSL, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEESU, ENPC, UPEC UP12