The Ediacaran volcanoclastic system of the Western Anti-Atlas (Morocco): Record of a rift – post-rift transition
The Upper Neoproterozoic volcano-sedimentary series are spectacularly exposed in the Anti-Atlas mountain ranges in Morocco. They offer a unique window into the tectonic-sedimentary and volcanic processes active during the transition between a rifting phase and a post-rift phase. In this context, our study aims to reconstruct the evolution of paleotopographies, and more specifically Ediacaran paleoreliefs, in order to understand the tectonic and volcanic processes responsible for their formation, as well as the mechanisms that have favored their preservation. Field observations within the inliers of the Western Anti-Atlas (Kerdous, Tagragra d'Akka, Aït Abdallah, Alma) have made it possible to recognize the nature and architecture of the last syn-rift series (Ouarzazate Group/PIII) and the post-rift ones (Adoudou Formation) of the Upper Neoproterozoic-Cambrian, as well as the syn-sedimentary tectonic structures that control them. In general, the rifting process begins with the activation of normal faults of variable directions, quickly followed by predominantly rhyolitic volcanism, whose deposits and lava flows are preserved in local tectonic depressions. Significant paleoreliefs become then apparent along the fault scarps. This pronounced paleotopography led to the formation of lacustrine fan-delta systems, recorded by large prisms of breccia deposits that quickly evolved to silty-carbonate facies in the axis of the newly formed depressions. These sedimentary or volcanosedimentary deposits gradually fossilize the paleoreliefs in a more homogeneous subsidence regime with reduced fault activity. A regional decrease in subsidence at the end of the rifting process is interpreted as the filling of the tectono-sedimentary systems, resulting in a flattened continental paleotopography. It was on this flattened paleosurface that the rise in relative sea level in the post-rift context led to the transgression of the peritidal platform deposits with microbial carbonate production of the Adoudou Formation at the Neoproterozoic-Cambrian transition. All of these series were then slightly deformed during the Hercynian orogeny to acquire their current arrangement in the Anti-Atlas inliers, without these appearing to be significantly influenced by the Neoproterozoic structures.
(. vol. 85, 11/10/2026)
ENSEGID, Bordeaux INP, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BRGM, ISTO, BRGM, INSU - CNRS, UO, CNRS, ISTO, BRGM, INSU - CNRS, UO, CNRS
Physical drivers of transport, dispersion and trapping of microplastics in a macrotidal, hyper-turbid fluvial–estuarine system: A modelling approach
Estuaries serve as both reservoirs and gateways for microplastics, yet the processes that control particle trapping, release, and redistribution are still insufficiently understood. This study assesses the relative importance of key physical processes in a macrotidal, hyperturbid Gironde estuary, influencing the transport and trapping of floating and settling microplastics -namely, interactions with shorelines, vertical mixing, effect of water density on particle buoyancy, interactions with bottom sediments, and microplastic-sediment flocculation and examines seasonal transport trends. Results show that floating microplastics are mainly exported seaward, although a fraction remains trapped as a longitudinal line in the middle estuary. The intensity of microplastic export and accumulation varies seasonally with river discharge. Shoreline interactions via beaching-refloating dynamics, along with flocculation with fine sediments, represent the dominant processes modulating the distribution and fate of floating microplastics. In contrast, settling microplastics exhibit limited export to the ocean and remain confined within the estuary. Although this retention is primarily governed by hydrodynamics, interactions with bottom sediments through (temporary or permanent) deposition and resuspension, as well as intra-tidal variability in vertical diffusivity, have a relatively stronger influence on the transport and distribution of settling microplastics. Two distinct accumulation zones, or Estuarine Microplastic Maxima (EMPM), are identified: a surface EMPM, formed by low-density floating particles associated with surface convergence, and a water-column EMPM of denser particles in suspension near the Estuarine turbidity maxima (ETM) linked to tidal pumping. Overall, macrotidal estuaries act as significant sinks for microplastics, where hydro-sedimentary dynamics govern particle retention and redistribution.
(Marine Pollution Bulletin. vol. 231, n° 0025-326X, pp. 119925, 11/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, SIAME, UPPA, MIO, IRD, AMU, INSU - CNRS, UTLN, CNRS, RHITME, Cerema, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS
Wave Input-Reduction for Shoreline Modelling of a High-Energy Environment with Complex Geological Settings
The long-term (decades) evolution of shoreline change along coastline (O(15)Km) with complex offshore wave transformation challenges both, state of the art process-based morphodynamics and reduce-complexity shoreline models. A major limitation is the computational time required to simulate the detailed spatiotemporal evolution of the wave field, particularly in regions where offshore wave refraction induces localized energy focusing. This study focuses on a 15-Km sandy coast on the North Medoc, southwestern France, characterized by high-energy, macro-tidal conditions, severe erosion, and complex offshore bathymetry. Effective coastal management strategies for the coming decades require the implementation of a reduced-complexity (RC) shoreline model. However, oversimplification of wave transformations in such a complex hydro-morphodynamic environment can result in flawed predictions of alongshore wavebreaking parameters and, consequently, shoreline change. Thus, a full wave propagation model is required, but computational time reduction techniques must be implemented to minimize computational cost. To address these challenges, this study introduces an easy-to-apply input reduction (IR) methodology that integrates offshore wave clustering to reduce computational costs when modeling long-term shoreline change within RC shoreline models.
(. vol. 42, pp. 652-658, 11/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BRGM
Non-stationary Model Free Parameter in Equilibrium Shoreline Modelling
The state-of-the-art equilibrium shoreline model proposed ShoerFor [1] is used to hindcast shoreline evolution. A similar approach to the work of Ibaceta et al. (2022) [2] is adopted, where they introduced non-stationary model free parameters to improve long term shoreline change predictions. An Ensemble Kalman Filter (EnKF) is implemented to track the temporal variability in model free parameters and explore if their evolution can be linked to the environmental forcing. A correlation between the winter wave energy and the model free parameter φ (beach memory) is identified where high energetic winters are followed by an increase in the parameter suggesting such time variation in beach memory can be parametrized.
(. vol. 42, pp. 646 - 651, 11/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BRGM, UNSW
Past trajectory of a Northwest Europe socio-ecosystem at the land-sea interface: Case study of the northern watersheds of the Bay of Brest over the last 150 years
The Bay of Brest (BB) is a macro-tidal estuarine environment that has been exposed to strong anthropogenic pressures over the past few decades, especially since the Second World War. This makes the BB an ideal site for studying coastal ecosystem transformations since the Industrial Revolution. We analysed five sediment cores collected in two key BB areas with varying exposure to marine hydrodynamic processes: i) the Elorn sector (3 cores) and ii) the Bay of Daoulas (2 cores) in the inner BB, close to the mouth of the Daoulas river. Our study used palynological (pollen and dinoflagellate cysts) and benthic foraminiferal assemblages, sedimentological data, and elemental geochemistry, at a very fine temporal resolution (2 to 16-year resolution). Working at a local spatial scale reveals robust correlations between the different driving forces and environmental changes over the last 150 years. Statistical analyses of these sedimentological and paleoecological time series reveal major breakpoints, specifically four key threshold periods: 1925–1938, 1960–1967, 1980–1987, and 2005, which are essential for understanding temporal changes in protist communities and the evolution of BB landscapes over this time period. Combining these findings with a reanalysis of regional precipitation patterns back to 1850, nutrient concentration data, and historical accounts of land-use practices, enables us to identify the main drivers of coastal ecosystem transformation. Our findings emphasize the strong influence of agricultural practices on trophic changes and the decline in the BB water quality, in agreement with coastal observatory series showing a notable increase in toxic algal blooms since the 1980s.
(Palaeogeography, Palaeoclimatology, Palaeoecology. vol. 690, n° 0031-0182, pp. 113703, 11/10/2026)
GEO-OCEAN, UBS, IFREMER, INSU - CNRS, UBO EPE, CNRS, BEEP, IFREMER, UBO EPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GEOARCHI, UBS, UBO EPE, IBSHS, UBO EPE, ENS Rennes, GR, UR, INSU - CNRS, CNRS, LEMAR, IRD, IFREMER, UBO EPE, CNRS, LMBA, UBS, UBO EPE, CNRS, UBS
Fluoride exposure affects development, thyroid-related gene expression and follicle histology in early life stages of rainbow trout (Oncorhynchus mykiss)
Endocrine disrupting chemicals (EDCs) are attracting growing interest due to their effects on humans and on ecosystems. Among suspected EDCs, fluoride is a widespread pollutant in aquatic ecosystems, particularly as a result of fluoridation of drinking water. It has also been described to affect fish development. The aim of this study was to determine if chronic fluoride exposure could affect early life-stages of rainbow trout (Oncorhynchus mykiss) especially their growth and thyroid hormone system. Trout embryos were exposed from 6 to 40 days post-fertilization, to 0, 1.5, 5, 17, 27.5 or 51.5 mg/L. Growth was significantly inhibited by the exposure with shorter larvae and delayed resorption of yolk sac. Fluoride exposure increased axial skeleton malformations, but had no effect on the occurrence of edema or hemorrhage. Genes tshβ, dio1, dio2, dio3, and thrα, coding for proteins involved in the thyroid hormone system, were overexpressed in a dose-dependent manner.
While histopathological changes of thyroid follicles were observed in larvae exposed to fluoride, no difference in the levels of thyroid hormones was highlighted. In conclusion, results indicate that fluoride exposure during early life stages of rainbow trout might affect their growth and development, and exhibit multisite effects on the thyroid hormone system.
(Environmental Science and Pollution Research, n° 0944-1344, 11/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, VIMEP, ANSES, COS, VU
The Early Homo Conundrum: Challenges and Potential Solutions
(Evolutionary Anthropology. vol. 35, n° 1060-1538, pp. e70043, 11/10/2026)
PACEA, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, HNHP, MNHN, UPVD, CNRS, SCU, LG / WGL
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, 11/10/2026)
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
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, 11/10/2026)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CEFREM, UPVD, INSU - CNRS, CNRS, ONF
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, 11/10/2026)
RHITME, Cerema, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LOMA, UB, CNRS