A continuous 500‐year sediment record of inundation by local and distant tsunamis in South‐Central Chile (40.1°S)
Abstract Chile's west coast is frequently struck by megathrust earthquakes and tsunamis, as illustrated by the CE 2010 Maule ( M w 8.8) and CE 1960 Valdivia ( M w 9.5) events. Despite numerous palaeoseismic and palaeotsunami studies, uncertainties remain regarding the rupture extent and tsunamigenic potential of M w 8–9 earthquakes. This study examines the sedimentary record of Laguna Gemela West, a coastal lake at 5–6 m a.s.l. and of 17.5 m depth. It is separated from the Pacific by a 400 m long channel bordered by northward‐propagating dunes and controlled by Pleistocene sandstones forming a knickpoint in the channel profile. Multiple sedimentary proxies (e.g. grain‐size, X‐CT, XRF scanning) identified five distinct sand‐enriched layers, interpreted as tsunami deposits. Age‐depth modelling (based on 137Cs and 14C) allowed linking these deposits to the CE 2010, 1960, 1837, 1737 and 1575 megathrust earthquakes. While historical records confirm significant tsunamis in CE 2010, 1960, 1837 and 1575, no reports exist for a CE 1737 tsunami. However, a potential tsunami deposit and evidence for subsidence were found at the nearby Chaihuín site, albeit with large dating uncertainty (CE 1600–1820). The more precise age for a sand layer at Laguna Gemela West (CE 1672–1746) supports the occurrence of a local tsunami in CE 1737. Additionally, deposits linked to the CE 1837 and 2010 events suggest tsunamis can impact sites >100 km adjacent to megathrust ruptures. A second pulse in the uppermost sand layer may reflect the CE 2011 Japan tsunami, which reached a similar height (~1.6 m a.s.l.) in the nearest tide gauge as the CE 2010 tsunami. Unlike coastal plain sites, which often require coseismic subsidence for deposit preservation, coastal lakes can capture a more complete tsunami history. This study highlights their complementary role in palaeotsunami research, providing insights in local, regional and transoceanic tsunami events.
(Depositional Record, n° 2055-4877, 28/07/2025)
UGent, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ICT
Benchmarking shoreline prediction models over multi-decadal timescales
Robust predictions of shoreline change are critical for sustainable coastal management. Despite advancements in shoreline models, objective benchmarking remains limited. Here we present results from ShoreShop2.0, an international collaborative benchmarking workshop, where 34 groups submitted shoreline change predictions in a blind competition. Subsets of shoreline observations at an undisclosed site (BeachX) over short (5-year) and medium (50-year) periods were withheld from modelers and used for model benchmarking. Using satellite-derived shoreline datasets for calibration and evaluation, the best performing models achieved prediction accuracies on the order of 10 m, comparable to the accuracy of the satellite shoreline data, indicating that certain beaches can be modelled nearly as well as they can be remotely observed. The outcomes from this collaborative benchmarking competition critically review the present state-of-the-art in shoreline change prediction as well as reveal model limitations, facilitate improvements, and offer insights for advancing shorelineprediction capabilities.
(Communications Earth & Environment. vol. 6, n° 2662-4435, pp. 581, 24/07/2025)
UNSW, USGS, TU Delft, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BRGM, UC / UniCan, CSIRO, ULISBOA
Effects of high overvoltages on the treatment of PFAS in water
The chemical structure of per-polyfluoroalkyl substances (PFAS), based on strong C-F bonds makes them extremely stable in the natural environments. Plasma technologies have a strong potential for degrading PFAS in water. Understanding of the plasma removal mechanisms is necessary to improve the efficiency and to better control the by-products. Here three types of discharges with the same deposition energy were investigated for plasma removal of PFAS. An AC and a nanosecond high voltage pulse discharge were used in a wire-to-water surface configuration, whereas an atmospheric pressure fast ionization wave was generated in a 3-pins configuration over the water surface.
(20/07/2025)
EM2C, CNRS, LSPM, USPC, CNRS, LPTC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Water Wars: competition between native and exotic isoetid species
Among several global changes, invasion by exotic species is often pointed out as responsible for the decline of native species. Indeed, in the competition for space and resources, fast-growing species are generally more efficient than native ones. The natural lakes along the Aquitaine coast are home to unique and protected populations of isoetid macrophytes, which are declining in the last decades. The present study aims at testing the potential competition between the native isoetid Lobelia dortmanna and the exotic isoetid Sagittaria graminea, both coexisting in Lake Cazaux-Sanguinet, France. To achieve this, we set up a multi-year monitoring program across 1x1m quadrats, with three conditions: native species only, exotic species only, and mixed condition when both species occurred. Each individual in the quadrat was spatially mapped and its photosynthetic activity was measured, as well as its leaf length and width. Sediment samples were also collected to analyze differences in organic matter content and granulometry between the quadrats. Preliminary results show that, while substrate analysis indicates similar biotopes for both species, their co-occurrence triggered significant physiological and morphological responses. Additionally, the native and exotic species appeared to follow different patterns of spatial distribution. However, these first results did not necessarily indicate a negative effect of the exotic species on the native one. Further field sampling in the coming years will help clarify the temporal spatial dynamics of the two species.
(20/07/2025)
UR EABX, INRAE, ECLA, USMB [Université de Savoie] [Université de Chambéry], INRAE, OFB, LPTC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Persistence of a wind-driven fire regime in Mediterranean France over the past 8200 years revealed by a marine paleoecological record
Data on paleofire activity in southeastern France during the Holocene are still lacking thus limiting our capability to anticipate fire regime shifts under climate change. Here, we present a 8.2 ky-long high-resolution time-series of microscopic charcoal (microcharcoal) particles from a marine sediment core retrieved from the Rhone prodelta, in the Gulf of Lions (NW Mediterranean Sea). Fire frequency, episodes, size and types of burnt vegetation were determined by quantifying microcharcoal and analysing its morphometry. Our results indicate an increase in biomass burning and fire frequency combined with a decrease in the mean elongation ratio from the Northgrippian (8.2–4.2 ka) to the Meghalayan (4.2–0 ka) stage. This pattern is interpreted as reflecting a shift from the burning of graminoids in closed mesophytic forests during the Northgrippian to the burning of shrub communities in open Mediterranean habitats during the Meghalayan. We also identified 20 fire episodes over the past 8.2 ka, occasionally coinciding with human occupations. Large fires occurred during cold events and summer droughts conditions of the Northgrippian. We relate this finding to negative phases of the North Atlantic Oscillation (NAO) and increased fuel load under wet winter conditions and fuel flammability under dry and strong summer winds. Besides climate and vegetation, human activity is likely to be an additional driver of fire during the Meghalayan. Southeastern France is currently identified as a region with a high wind-driven fire risk, although its fire regime analysis is biased by intensive fire suppression. We suggest that wind-driven large fires is an inherent element of fire and weather patterns in this area rather than the result of fire suppression strategies leading to uncontrollable large fires.
(The Holocene. vol. 35, n° 0959-6836, pp. 961-976, 13/07/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CEFE, EPHE, PSL, CNRS, IRD [Occitanie], INRAE, Institut Agro, UM, UMPV, IMBE, AU, AMU, CNRS, CEFREM, UPVD, INSU - CNRS, CNRS, UMLP, LCE, CNRS, UFC, UBFC, LOCEAN-VOG, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, UVSQ, CEA, INSU - CNRS, X, CNES, SU, CNRS, UPCité, EPOC
Analyse des tendances de contaminations historiques multi-métalliques dans les archives sédimentaires de la Saône (années 1940 - actuel)
In order to understand the evolution of metallic contaminant flux in the Saone River towards Lyon over time, two sediment cores were studied. These cores provide records spanning over 80 years with relatively continuous and homogeneous deposition. Age models were established based on radionuclide profiles (137Cs and 210Pb), defining high deposition rates (1–2 cm. yr⁻¹) that enable to study contaminant trends at high temporal resolution. These analyses reveal distinct contamination phases linked to the industrial history of the basin. Based on the chronology covered by these sediment archives, copper, lead, and cadmium contamination can be identified as early as the 1950s, with peaks extending during the 1970s. Later, while contamination levels of these metals, silver reaches maximal concentrations at two periods, in the 1970s and 1980s, and then during the 1990s. Within the industrial context of the basin, silver contamination can be associated with the photographic industry. These findings show that secondary channels of the Saone River have been affected by multi-metallic contamination accumulated since the 1950s. They act as pollution archives, enabling the reconstruction of the consequences of anthropogenic activities on river ecosystems. Moreover, this stock of metallic contaminants requires integrated management within the framework of secondary channel restoration efforts.
(09/07/2025)
LEHNA, UCBL, ENTPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EVS, ENS de Lyon, Mines Saint-Étienne MSE, IMT, UL2, UJML, INSA Lyon, INSA, UJM, ENTPE, ENSAL, CNRS, ALLHiS, UJM
Cryosphere and ocean variability in Kane Basin since the 18th century: insights from two marine multi-proxy records
Abstract. Nares Strait, a marine gateway connecting the Arctic Ocean with northern Baffin Bay, is characterised by the formation of a seasonal ice bridge between Canada and Greenland, that prevents the southward export of multiyear sea ice. Recent observations indicate increasing instability in sea-ice formation, particularly evident in Kane Basin, which either freezes over or remains open during winter and spring depending on ice-bridge dynamics. The Kane Basin is influenced by contrasting ocean currents in its eastern and western sides, as well as by the Humboldt Glacier, Greenland’s widest marine-terminating glacier. Kane Basin is a critical region due to its pronounced sensitivity to cryospheric and oceanic changes. However, its long-term environmental history, particularly in the eastern sector, remains poorly constrained prior to the satellite era. Here, we present two multi-proxy sediment core records from opposite sides of Kane Basin, spanning from the 18th century to the present, that we compare with Humboldt Glacier frontal positions since 1965 CE. Clear spatial differences are evident across the basin in terms of sediment delivery, primary productivity, and the source of organic matter. Both records also reveal temporal changes, transitioning from cold sea-surface conditions with extensive sea ice during the Little Ice Age (peaking around 1900 CE), towards more open and stratified waters, accompanied by increased primary production from approximately 1950 CE to the present.
(Climate of the Past Discussions [Climate of the Past Preprints], n° 1814-9340, 08/07/2025)
UCPH, LOCEAN-VOG, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, UVSQ, CEA, INSU - CNRS, X, CNES, SU, CNRS, UPCité, GEUS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, METIS, EPHE, PSL, INSU - CNRS, SU, CNRS, ULaval, INSU - CNRS, CNRS, UNB
Cartographie du Réservoir Utile Maximal en eau des sols à partir des Référentiels Régionaux Pédologiques
Le Réservoir en eau Utilisable (RU) des sols est la quantité d’eau qu’un sol peut retenir et restituer aux plantes. Cet indicateur dépend de la texture du sol, c’est-à-dire des proportions d’argiles, limons et sables, ainsi que de sa profondeur et de sa proportion d’éléments grossiers. La teneur en carbone du sol a également été identifiée comme prédicteur important du RU lorsqu’il est estimé par une fonction de pédotransfert (Román Dobarco et al., 2019). La disponibilité de données sur les sols augmente en France, notamment par l’effort de réalisation des Référentiels Régionaux Pédologiques (RRP) dans le cadre du programme « Inventaire, Gestion et Conservation des Sols » (IGCS) coordonné par le Groupement d’intérêt Scientifique Sol. Ces systèmes d’informations spatialisées sur les sols à l’échelle 1/250 000 présentent une base sémantique riche qui peut être valorisée à travers des cartographies thématiques de propriétés fonctionnelles des sols à l‘échelle régionale. Dans ce contexte, notre étude vise à proposer une procédure pour calculer et cartographier aisément et de façon quasi-automatique le RU à partir d’un RRP, sous la forme d’un un script en langage Python. Afin de minimiser les échecs de calcul dus à d’éventuelles données manquantes, le script implémente un arbre de décisions permettant de compléter la base de données en utilisant d’autres variables pédologiques disponibles ou à dires d’expert. Le script a été testé sur des jeux de données partiellement incomplets afin d’évaluer sa fiabilité en présence de données manquantes. L’application de ce script au RRP de Bretagne a permis de générer des cartes du RU estimé sur une épaisseur de sol de 1 mètre à partir de trois sources de données : (1) la base de données DoneSol du RRP avec une représentation de la valeur du RU par Unités Cartographiques de Sol ; (2) les données issues de la spatialisation des Unités Typologiques de Sol (Vincent et al., 2016) du RRP Bretagne projetées sur une grille raster au pas de 50 mètres et (3) les propriétés pédologiques à la même résolution dérivées par tranche de profondeur selon les spécifications GlobalSoilMap. Les cartes (2) et (3) du RU ont été comparées aux résultats préexistants, dont la carte du RU nationale à une résolution de 90 mètres (Román Dobarco et al. 2021), ainsi que la carte issue des données de SoilGrids. Cette étape rend compte de la pertinence des différents niveaux de précision en fonction des usages de l’information produite. De plus, l’utilisation de données locales exhaustives permet d’obtenir une carte du RU englobant la variabilité induite par les spécificités pédologiques régionales, telles que les sols issus de limons éoliens sur la frange nord de la région et jusqu’au centre de l’Ille-et-Vilaine, ou bien les Monts d’Arrée en Bretagne, dans le Finistère. Enfin, ce script offre une valorisation rapide et accessible des données des RRP, que l’on peut déployer à l’échelle d‘autres régions. La démarche employée dans notre étude ouvre également des perspectives quant à la complétion des bases de données, et au calcul de nouveaux indicateurs de qualité des sols.
(07/07/2025)
SAS, INRAE, Institut Agro, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, Bordeaux Sciences Agro
OntoPFAS : Ontologie des PFAS et de leur exposition
La construction d'ontologies est une des premières tâches dans le domaine de la représentation des connaissances. Elle reste très pertinente aujourd'hui, grâce à l'expressivité des langages formels, qui permettent encore d'explorer et de découvrir des connaissances. Pendant des décennies, la communauté a développé des méthodologies pour la construction manuelle d'ontologies, et plusieurs classifications de celles-ci ont été proposées. Dans cet article, nous présentons une méthodologie de construction d'ontologie basée sur des méthodes existantes, et nous l'appliquons à la représentation du domaine des PFAS (Per-et poly-fluoroalkyle substances) et de leur exposition. Les PFAS sont des substances dont la structure chimique particulière les rend très résistantes et efficaces dans de nombreuses applications industrielles. Ils suscitent un intérêt croissant en raison de leur impact négatif sur la santé et l'environnement. Ce travail s'inscrit dans le cadre du projet interdisciplinaire DAE (Détection d'Anomalies Environnementales).
(pp. 7 p., 02/07/2025)
MISTEA, INRAE, Institut Agro, LIB, UBE, LIRMM | ADVANSE, LIRMM, UPVD, Inria, CNRS, UM, UMPV, PRODIG (UMR_8586 / UMR_D_215 / UM_115), UP1, IRD, SU, CNRS, UPCité, LPTC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Effects of Microplastic-Sediment Interactions on Microplastics Dispersion in the Gironde Estuary: A Modelling Approach
(01/07/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UPPA, Cerema Direction Est, Cerema