Colloid-facilitated release of PFAS from polluted-soil monoliths
Firefighting Aqueous Film Forming Foams contain per- and polyfluoroalkyl substances (PFAS). Because PFAS are persistent, firefighting training sites constitute a source of soil and groundwater contamination. Colloidal soil particles are known to facilitate the mobility of contaminants that have a strong affinity for soils. Indeed, colloid-facilitated transport of PFAS has been brought up repeatedly to discuss experimental observations regarding PFAS mobility. Still, it has only been observed experimentally for two PFAS molecules, using model experimental situations: repacked soil columns spiked with PFAS. We investigated for the first time the determinants and extent of colloid-facilitated transport of PFAS from AFFF-impacted undisturbed-soil monoliths during simulated rainfalls. These experiments showed that : (i) colloids contributed to the mobility—up to 70% of their concentration in leachates—of 12 PFAS having a perfluorinated carbon chain length nc ≥6, out of the 20 PFAS present in leachates; (ii) PFAS content in colloids was up to 25 times higher than in bulk soil, this enrichment stemmed from the adsorption on colloids of PFAS present in the soil solution; (iii) colloid-facilitated transport was exacerbated during transient flow regimes, which was probably related to the adsorption of PFAS and colloids to the moving air-water-interfaces. In addition, diffusion was the mechanism limiting the mobility of eight other PFAS with nc ≤7 and hydrodynamic conditions, linked to the soil structure, strongly affected the mobility of PFAS. The importance of colloidal particles as a carrier phase of PFAS calls for a renewed conceptual model of PFAS fate in soils.
(Journal of Hazardous Materials. vol. 511, n° 0304-3894, pp. 142279, 03/09/2026)
EMMAH, AU, INRAE, GERS-LEE, LPTC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IRSTV, BRGM, UA, ULR, Cerema, CNRS, INSIS - CNRS, IMT Atlantique, IMT, Nantes Univ, Nantes Univ - ECN, Nantes Univ, Nantes Univ - ENSA Nantes, Nantes Univ, Institut Agro
The Early Homo Conundrum: Challenges and Potential Solutions
(Evolutionary Anthropology. vol. 35, n° 1060-1538, pp. e70043, 03/09/2026)
PACEA, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, HNHP, MNHN, UPVD, CNRS, SCU, LG / WGL
From Fixed to Transgressive Dunes, the Conditions and Timing of the Transition Along the Aquitaine Coast, France
Today most of the coastal dunes in temperate latitudes, especially in the northern hemisphere, are relatively stable. However, over the last decade, the Gironde coast, southwest France, has experienced substantial natural dune remobilization following a major marine erosion event. Annual, large-scale and high-resolution, airborne LiDAR data and Satellite imagery (Sentinel-2) are combined to address the coastal dune morphological changes and establish relations with forcing and controlling factors (vegetation cover, geomorphological descriptors). Between 2014 and 2023, about 10 out of 85 km of the Gironde dunes have switched from fixed to transgressive state. The analysis showed that in the vast majority of the cases the dominant process involved was dune front cannibalism. However, there is considerable spatial and temporal variability along the coast, depending on the vegetation cover evolution, the amount of sediment remobilized and the morphological characteristics of the dunes (steepness of the front slope, width)
(. vol. 41, pp. 10 - 15, 03/09/2026)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CEFREM, UPVD, INSU - CNRS, CNRS, ONF
Past Ocean surface density from planktonic foraminifera calcite δ18O
Density of seawater is a critical property that controls ocean dynamics. Previous works suggest the use of the δ18O calcite of foraminifera as a potential proxy for paleodensity. However, potential quantitative reconstructions were limited to the tropical and subtropical surface ocean and without an explicit estimate of the uncertainty in calibration model parameters. We developed the use of the δ18Oc of planktonic foraminifera as a surface paleodensity proxy using Bayesian regression models calibrated to annual surface density. Predictive performance of the models improves when we account for inter-species specific differences. We investigate the additional uncertainties that could be introduced by potential evolution of the δ18Oc-density relationship with time – from the last glacial maximum (LGM) to the preindustrial (PI) – through the combination of past isotope enabled climate model simulations and a foraminiferal growth module. We demonstrate that additional uncertainties are weak globally, except for the Nordic Seas region. We applied our Bayesian regression model to LGM and Late Holocene (LH) δ18Oc foraminifera databases to reconstruct annual surface density during these periods. We observe stronger LGM density value changes at low latitudes compared to mid latitudes. These results will be used to evaluate numerical climate models in their ability to simulate ocean surface density during the extreme climatic period of the LGM. The new calibration has great potential to reconstruct the past temporal evolution of ocean surface density over the Quaternary. Under climates outside the Quaternary period and in ocean basins characterized by anti-estuary circulation, like the current Mediterranean Sea and Red Sea, our calibration could provide density estimates with larger uncertainty, a point that requires further investigations.
(Climate of the Past. vol. 22, n° 1814-9324, pp. 247-263, 03/09/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ICM, CSIC, CRM, UAB, AWI, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, PSL, UVSQ, CEA, INSU - CNRS, X, IP Paris, CNES, SU, CNRS, UPCité, VU, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, CLIM, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA
Influence of Estuarine Turbidity Maximum Dynamics and River Discharge on Tide Propagation in Two Fluvial-Estuarine Systems
Tidal propagation in estuaries is shaped by the balance between morphological convergence and frictional effects, yet the influence of mud deposition associated with estuarine turbidity maxima remains unexplored. This study investigates the influence of Estuarine Turbidity Maxima (ETM) dynamics and river discharge on tidal propagation in the Loire and Gironde estuaries, combining frequency analysis of high-frequency observational data with an analytical model. Enhanced Harmonic Analysis reveals a tipping section-located downstream of the saline intrusion limit-in both hyperturbid systems, beyond which tidal properties (amplification, distortion, asymmetry) become highly sensitive to river discharge. Decomposing total friction into tidal, riverine, and interaction terms shows that the tipping point marks a regime shift where tide-river interaction dominates under low flow conditions, while the river term dominates during high discharge. Observations show that seasonal and interannual ETM-induced changes in bottom roughness can modulate tidal amplification by up to 35%, a mechanism confirmed by idealized modelling, while morphological changes have a more limited effect at these scales. Finally, scenario-based simulations suggest that sealevel rise and anthropogenic deepening may further enhance tidal amplification, 1 potentially promoting the upstream migration of salinity and turbidity maxima, with broader implications for estuarine functioning under future climate and human pressures.
(Estuaries and Coasts. vol. 49, n° 1559-2723, pp. 68, 03/09/2026)
RHITME, Cerema, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LOMA, UB, CNRS
Global biosphere productivity response to Atlantic Meridional Overturning Circulation collapse during Heinrich Stadial 4
The slowdown of the Atlantic Meridional Overturning Circulation (AMOC) due to ongoing climate change raises concerns about its impact on the global carbon cycle. Understanding how global biosphere productivity may respond to such changes is essential for predicting the future carbon cycle, yet quantifying past global biosphere productivity remains challenging. We use triple isotope composition of air oxygen ( 17 Δ) trapped in polar ice cores to reconstruct the global biosphere productivity over the period 40.5 to 38.6 thousand years before the present (ka B.P.), covering Heinrich Stadial 4, a period of weakened AMOC. Our data reveal a slight increase in productivity following a carbon dioxide (CO 2 ) rise around 39.5 ka B.P. Freshwater hosing experiments using a global climate model indicate that the CO 2 fertilization effect on the terrestrial biosphere offsets productivity decline caused by consequences of AMOC slowdown. Collectively, our results suggest that global biosphere productivity slightly increases in response to AMOC slowdown and accompanying changes.
(Science Advances. vol. 12, n° 2375-2548, pp. eaea0455, 03/09/2026)
LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, IPSL (FR_636), ENS-PSL, PSL, UVSQ, CEA, INSU - CNRS, X, IP Paris, CNES, SU, CNRS, UPCité, NBI, UCPH, CLIM, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GLACCIOS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, MOSAIC, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, MERMAID, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Sinking Together? Settling Behavior of Microplastics in the Presence of Fine Sediments
Predicting microplastic (MP) transport in aquatic environments requires understanding how particle properties, hydrodynamics, and aggregation processes control vertical transport, particularly in turbid systems. Here we investigate how particle physical properties and interactions with fine sediments influence the settling velocity of small MPs (<125 μm) under controlled laboratory conditions. We propose a novel methodology using an optical settling column (SCAF) to measure the settling velocity of MPs with contrasting sizes, shapes, and densities, both as dispersed particles and in mixtures with fine cohesive sediments at concentrations typical of turbid environments, under three treatments: dispersed, preagitated, and prerested. Settling velocities of dispersed MPs were primarily governed by size and density with minor shape effects. Empirical models developed for natural particles accurately predicted the MP settling in this size range. In MPsediment mixtures, the settling behavior varied markedly with particle properties and treatment conditions. Irregular particles, particularly fragments, exhibited flocculation under all treatments and higher settling velocities, whereas larger spheres interacted weakly with sediments and settled independently. Under prerested conditions, most particles showed enhanced and more uniform settling, with floc velocities converging around ∼0.5-0.6 mm/s. These findings offer insights into aggregation-driven vertical transport and provide a basis for improving predictive models in turbid environments.
(Environmental Science and Technology. vol. 60, n° 0013-936X, pp. 10251-10262, 03/09/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UAS, RHITME, Cerema, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS
Morphological Development and Evolution of Barchanoid Dunes on the Cap Ferret Coastal Spit
Barchans are crescent-shaped dunes with their convex side facing the wind and their horns pointing downwind, commonly observed in deserts but also in coastal environments. This study investigates the dune field of the Cap Ferret Spit (5-km wide, 23-km long; Atlantic Coast, SW France) including of series of barchanoids dunes, currently stabilized by forest cover. The aims are to classify each dune into distinct typologies and characterize their morphology in order to analyze their evolution. LiDAR-based analysis identified four distinct barchanoid dune types. Moreover, it revealed superimposed bedforms on the dunes, including draping and oscillating patterns, reflecting the influence of consistent wind regimes during dune development and migration. This study proposes an evolutionary sequence in which proto-barchans evolve into barchanoid ridges and eventually as mature isolated barchans. These findings provide insight into the geomorphological evolution of barchanoid dunes in a coastal context, and particularly their migration pattern on a coastal spit system
(. vol. 41, pp. 41 - 47, 03/09/2026)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Late Holocene coastal sand-drift events and long-term socio-ecological resilience (Béniguet Island, Western France)
(Aeolian Research. vol. 76, n° 1875-9637, pp. 101048, 03/09/2026)
LETG - Brest, UBO EPE, UR2, CNRS, LETG, UBO EPE, UR2, CNRS, Nantes Univ - IGARUN, GR, UR, INSU - CNRS, CNRS, UBO EPE, CNRS, UP1, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, Inrap
Rôle de la variabilité spatio-temporelle de la couverture végétale sur la migration des cordons dunaires en Gironde
La détection et le suivi de la variabilité spatio-temporelle de la végétation dunaire sont déterminants afin de comprendre et anticiper les évolutions morphodynamiques des cordons dunaires. En comparaison avec d'autres régions européennes plus septentrionales, où la végétation dunaire est plus dense et dont les limites spatiales sont plus facilement identifiables, la végétation dunaire en Nouvelle-Aquitaine est plus éparse et sa détection et quantification représentent un défi scientifique. Une nouvelle méthode couplant l'imagerie satellitaire (Sentinel-2, 10 x 10 m) et l'utilisation d'un réseau de neurones (S2DR3) est présentée dans cette étude. Cette méthode permet d'obtenir une cartographie d'un indicateur de végétation (NDVI) à haute résolution spatiale (1 x 1 m) et de renouveler l'opération à une fréquence annuelle. L'évaluation des erreurs de géoréférencement (< 5 m) et de la cohérence spectrale des images satellite (0.73 < R < 0.86) a démontré la fiabilité de cette méthode, permettant d'analyser les variations spatio-temporelles de la végétation. Les résultats ont montré une diminution des valeurs de NDVI, de plus de moitié entre 2017 et 2024 avec de fortes disparités spatiales le long d'une section dunaire de 500 mètres située au nord de Carcans Plage (Gironde). En associant cette cartographie de la végétation avec des données topographiques (LiDAR aéroporté), des interactions entre la dynamique de végétation et les changements morphologiques ont pu être identifiées en mettant en évidence différents niveaux de couverture de végétation et de mobilité sédimentaire. Ces données offrent également de nouvelles perspectives, comme notamment leur intégration dans des modèles numériques morphodynamiques afin d'avoir une compréhension plus fine des interactions entre la végétation et la dynamique sédimentaire
(03/09/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BRGM