Investigating beachgoer’s perception of coastal bathing risks in southwest France
Sandy beaches offer numerous health and well-being benefits, but engaging in water-based recreational activities also exposes beachgoers to risks from natural hazards, such as rip currents and waves that break at the shoreline (shore break waves), which can result in fatal drownings and surf zone injuries. A contributing factor to these incidents is that individuals often misunderstand the risks they are exposed to. This study used a unique multidisciplinary database combining beachgoer surveys, marine and weather data and lifeguard hazards assessments to examine beachgoer’s risk perception at a beach located in southwest France. We identified a number of factors that can have potentially contradictory influences on beachgoers’ perceptions. Beachgoers’ perceived risk of rip current and shore break hazards increases with increasing wave height and increasing wave period. Tide level has a significant statistical influence on individuals’ perceived risk of the shore break wave hazard only. Beachgoers familiar with La Lette Blanche beach had higher rip current and shore break risk perceptions although regular recreational beach users (in general) tend to underestimate risks. Similarly, males and younger people express lower perceived risks compared to others. For a large number of environmental conditions, beachgoers perceive rip currents to be a greater risk than shore breaks wave risks although they tend to overestimate beach hazards compared to lifeguards. These results create new avenues for preventive communication, in particular by emphasizing the danger of shore breaks, and the specific nature of the risks on the beaches of south-west France. Some of these safety messages should communicated well before the beachgoers arrive at the beach.
(Natural Hazards. vol. 120, n° 0921-030X, pp. 13209–13230, 10/04/2026)
UR ETTIS, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UNSW
Comparative assessment of the acute toxicity of commercial bio-based polymer leachates on marine plankton.
Conventional plastics have become a major environmental concern due to their persistence and accumulation in marine ecosystems. The development of potential degradable polymers (PBP), such as polyhydroxyalkanoates (PHAs) and polylactic acid (PLA), has gained attention as an alternative to mitigate plastic pollution, since they have the potential to biodegrade under certain conditions, and their production is increasing as replacement of conventional polyolefins. This study aimed to assess and compare the toxicity of leachates of pre-compounding PBP (PLA and the PHA, polyhydroxybutyrate-covalerate (PHBv)) and polypropylene (PP) on five marine planktonic species. A battery of standard bioassays using bacteria, microalgae, sea urchin embryos, mussel embryos and copepod nauplii was conducted to assess the toxicity of leachates from those polymers. Additionally, the presence of chemical additives in the leachates was also verified through GC-MS and LC-HRMS analysis. Results showed that PHBv leachates exhibited higher toxicity compared to other polymers, with the microalgae Rhodomonas salina, being the most sensitive species to the tested leachates. On the other hand, PP and PLA generally displayed minimal to no toxicity in the studied species. Estimated species sensitivity distribution curves (SSD) show that PHBv leachates can be 10 times more hazardous to marine plankton than PP or PLA leachates, as demonstrated by the calculated Hazardous Concentration for 5 % of species (HC). Qualitative chemical analysis supports the toxicological results, with 80 % of compounds being identified in PHBv leachates of which 2,4,6-trichlorophenol is worth mentioning due to the deleterious effects to aquatic biota described in literature. These findings underscore the fact that whereas environmental persistence can be targeted using PBP, the issue of chemical safety remains unsolved by some alternatives, such as PHBv. Gaining a comprehensive understanding of the toxicity profiles of PBP materials through a priori toxicological risk assessment is vital for their responsible application as alternatives to conventional plastics.
(Science of the Total Environment. vol. 946, n° 0048-9697, pp. 174403, 10/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ULPGC, IEO | CSIC, CSIC
Range extension and morphological variability of Ophioderma longicaudum (Echinodermata: Ophiuroidea) at the South-West Atlantic coast of France
Specimens of the brittle star genus Ophioderma were found at the South-West Atlantic coast of France. They were sampled between 2 and 40 m depth. Morphologically, these specimens were most similar to O. longicaudum and O. hybridum. Molecular analysis for a mitochondrial marker (COI) and nuclear marker EF1 sequences from twelve specimens showed that only O. longicaudum was present in this study, with a higher morphological variability than previously described. They represent the northernmost confirmed record for this species, yet.
(Cahiers de Biologie Marine. vol. 65, n° 0007-9723, pp. 125-132, 10/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IMBE, AU, AMU, CNRS, NRM, MESRS, LERAR, COAST, IFREMER, LERPAC, COAST, IFREMER
Réduction des oxydes de fer, déstockage du carbone des sols noyés, et émission de méthane par un réservoir tropical
Les grands lacs artificiels créés par les barrages hydro-électriques tropicaux contribuent largement aux émissions de gaz à effets de serre (GES) par les hydrosystèmes continentaux. Bien que ces réservoirs d’eau aient noyé des sols, la minéralisation à long terme de la matière organique (MO) qu’ils contiennent est très peu documentée dans la littérature. La mise en eau du réservoir de Petit Saut en 1994 a noyé plus de 300 km2 de forêt tropicale et provoqué l'anoxie de l'hypolimnion et l’émission d’un flux considérable de GES. Après un pic en 1996-1998, les concentrations de CH4 dissous dans les eaux en sortie de barrage ont fortement diminué entre 1998 à 2005, et se sont stabilisées à un niveau faible depuis. Le parallélisme entre évolutions du fer et du méthane dissous dans les eaux en sortie de barrage suggère qu’ils proviennent de la réduction des sols noyés. La comparaison de sols témoins prélevés sous forêt en bordure de la retenue et de sols noyés depuis 25 ans montre : - Une baisse de près de 50 % de la teneur en MO des sols noyés par rapport aux sols témoins, ainsi qu’une baisse de l’indice d’hydrogène de la MO, et une augmentation de son δ13C, ce qui suggère une minéralisation rapide de la MO des sols en l’absence d’oxygène et surtout de sa fraction la plus énergétique. - Une forte corrélation entre teneurs en MO et en oxyde de fer dans les sols témoins, qui devient faible dans les sols noyés. En revanche, la faible corrélation entre Fe-oxyde et Fe-amorphe dans les sols témoins devient forte dans les sols noyés, ce qui suggère une transformation de Fe oxyde en Fe amorphe. Les taux de minéralisation de la MO des sols témoins et noyés rapportés à leur teneur en carbone, mesuré en anoxie au laboratoire, diffère peu, ce qui suggère une minéralisation continue et permanente de la MO des sols noyés. En revanche, le taux de production de méthane par les sols noyés est très faible. Les âges 14C de la MO des sols noyés, des bulles de méthane présentes dans ces sols, et du méthane dissous dans l'hypolimnion près du barrage sont proches de l'âge de la retenue. L’ensemble suggère qu’une fraction de MO réactive des sols, liée aux oxy-hydroxydes de fer, libérée par réduction et dissolution du fer lorsque les sols sont noyés, est la source à court et à long terme du méthane et d’une fraction importante des GES émis pas les réservoirs tropicaux.
(Étude et Gestion des Sols. vol. 31, n° 1252-6851, pp. 141-159, 10/04/2026)
CARRTEL, USMB [Université de Savoie] [Université de Chambéry], INRAE, Fédération OSUG, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BEF, INRAE, LEHNA E3S, LEHNA, UCBL, ENTPE, CNRS, LEHNA BAH, LEHNA, UCBL, ENTPE, CNRS
Impact of organic matter of different origins on lanthanum speciation, bioavailability and toxicity toward a green alga
Natural dissolved organic matter (DOM) is a heterogeneous mixture of a variety of organic compounds, with a great importance for the environmental fate of metals and their ecotoxicity. However, its complex nature and variable composition make the understanding of its role a challenge. Lanthanum (La) has a strong affinity for DOM and is one of the rare earth elements that is widely used in many electronic and green technologies, and for which the demand may potentially increase for the foreseeable future. The present study examines the links between the optical and chemical properties of organic matter and its influence on the bioavailability and toxicity of La toward the green microalga Chlorella fusca. A total of four DOMs, two natural organic matter samples from Ontario (Luther Marsh and Bannister Lake) and two Suwannee River fulvic and humic acids, were characterized by absorbance and fluorescence spectroscopy as well as by asymmetrical flow field-flow fractionation. These suggest that Luther Marsh and the Suwannee River humic acid have higher molecular weight and are more aromatic, compared to the other two DOMs. The concentrations of free metal ion La3+ were measured by an ion exchange technique and a partial ultrafiltration method, and related to biological response. Toxicity tests over 96 h at pH = 5.0 were separately conducted with and without 3 mg C·L−1 of each DOM. All DOM samples reduced La bioavailability but as opposed to what can be expected based on the Biotic Ligand Model, the presence of DOM exacerbated the toxicity of La and its accumulation in algal cells when only the free La3+ ion concentration was considered. These results indicate that the role of natural organic matter in modulating metal bioavailability remains to be deciphered.
(Frontiers in Environmental Chemistry. vol. 5, pp. 1342500, 10/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Changes over time in organic matter dynamics and copper solubility in a vineyard soil after incorporation of cover crop residues: Insights from a batch experiment
Cover crops (CCs) are increasingly used in viticulture because they benefit the soil and the environment in many ways. This study investigated the extent to which the incorporation of CC residues altered organic matter (OM) and Cu dynamics in a Cu-contaminated vineyard topsoil. A 92-day incubation period was used to monitor changes over time in carbon mineralization, carbon hydrolytic enzyme activity, concentration and optical properties of dissolved organic matter (DOM), and Cu solubility after the addition (or not) of two CC residues, oat or faba bean. The results revealed that adding CCs transitorily increased the concentration of DOM in soil solution, as well as the activity of C hydrolytic enzymes and C mineralization rates. DOM content was approximately two orders of magnitude higher in CC-amended soils than in the control soil on day 0, after which it gradually decreased to reach concentrations similar to those measured in the control soil on day 92. Analyses of DOM optical properties showed that its molecular weight and degree of humification increased over time with a decrease in its concentration. The close relationship between DOM and Cu concentrations in the soil solution suggests that degradation of CCs releases soluble forms of C capable of complexing and solubilizing Cu, and hence that incorporating CC residues can transitorily increase the solubility of Cu in vineyard topsoils. Despite their different C:N ratios, oat and faba bean had almost the same effect on Cu dynamics, implying that C inputs played a prominent role in explaining the interactions between OM and Cu within the timeframe of our experiment. In conclusion, this study enabled recommendations on how to mitigate the risk of Cu ecotoxicity associated with incorporating CCs in Cu-contaminated vineyard soils.
(Chemosphere. vol. 350, n° 0045-6535, pp. 141137, 10/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR ISPA, Bordeaux Sciences Agro, INRAE
Morphological vs. molecular identification of trematode species infecting the edible cockle Cerastoderma edule across Europe
Identifying marine trematode parasites in host tissue can be complicated when there is limited morphological differentiation between species infecting the same host species. This poses a challenge for regular surveys of the parasite communities in species of socio-economic and ecological importance. Our study focused on identifying digenean trematode species infecting the marine bivalve Cerastoderma edule across Europe by comparing morphological and molecular species identification methods. Cockles were sampled from ten locations to observe the trematode parasites under a stereomicroscope (morphological identification) and to isolate individuals for phylogenetic analyses using two gene markers, the small sub-unit ribosomal (18S) RNA gene (SSU rDNA) and the mitochondrial cytochrome c oxidase subunit 1 (cox1). For the first time, we compared both morphological identification and phylogenetic analyses for each of the 13 originally identified species. First, we identified a group of five species for which morphological identification matched molecular results (Bucephalus minimus, Monorchis parvus, Renicola parvicaudatus, Psilostomum brevicolle, Himasthla interrupta). Second, we identified a group of six species for which molecular results revealed either misidentifications or cryptic diversity (Gymnophallus choledochus, Diphterostomum brusinae, Curtuteria arguinae, Himasthla quissetensis, H. elongata, H. continua). Third, our analyses showed that all sequences of two expected species, Gymnophallus minutus and G. fossarum, matched between the two, strongly suggesting that only G. minutus is present in the studied area. Our study clearly demonstrates that molecular tools are necessary to validate the trematode species composition. However, with 17 distinct genetic lineages detected, some of which are not fully identified, future studies are needed to clarify the identity and status (regular vs. accidental infection) of some of these cryptic trematode species.
(International Journal for Parasitology: Parasites and Wildlife. vol. 25, n° 2213-2244, pp. 101019, 10/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Resource partitioning of a Mexican clam in species-poor Baltic Sea sediments indicates the existence of a vacant trophic niche
Invasive species are often generalists that can take advantage of formerly unexploited resources. The existence of such vacant niches is more likely in species-poor systems like the Baltic Sea. The suspension feeding wedge clam, Rangia cuneata, native to estuarine environments in the Gulf of Mexico, was sighted for the first time in the southeastern Baltic in 2010 and a few years later in the northern Baltic along the Swedish coast. To explore possible competition for food resources between R. cuneata and the three native clams inhabiting Baltic shallow soft bottoms, stable isotope and fatty acid analyses were conducted. There was no overlap between R. cuneata and any of the native species in either stable isotope or fatty acid niches. This suggests efficient partitioning of resources; multivariate analyses indicate that separation was driven mainly by δ$^{13}$C and by fatty acids reflecting diatoms and cyanobacteria, respectively (e.g. 16:1ω7 and 18:3ω3). R. cuneata reflected seasonal variation in phytoplankton more than other clams reflecting higher trophic plasticity. In conclusion, the addition of R. cuneata to the Baltic shallow soft bottoms suggests the existence of a vacant trophic niche in these sediment habitats, however the long-term effects on other species and nutrient cycling requires further studies focusing on the population dynamics of R. cuneata and its impact on the Baltic Sea ecosystem
(Scientific Reports. vol. 14, n° 2045-2322, pp. 12527, 10/04/2026)
FTMC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Spatial Interpolation and Conditional Map Generation Using Deep Image Prior for Environmental Applications
Kriging is the most widely used spatial interpolation method in geostatistics. For many environmental applications, kriging may have to satisfy the stationarity and isotropy hypothesis, and new techniques using machine learning suffer from a lack of labeled data. In this paper, we propose to use Deep Image Prior, which is a U-net-like deep neural network designed for image reconstruction, to perform spatial interpolation and conditional map generation without any prior learning. This approach allows to overcome the assumptions for kriging, as well as the lack of labeled data, while proposing uncertainty and probability above a certain threshold. The proposed method is based on a convolutional neural network that generates a map from random values by minimizing the difference between the output map and the observed values. From this new method of spatial interpolation, we generate n maps in order to have a map of uncertainty and a map of probability of exceeding the threshold. The conducted experiments demonstrate the relevance of the proposed methods for spatial interpolation, on both the well-known digital elevation model data and the more challenging case of pollution mapping. The obtained results with the three datasets demonstrate the competitive performance compared with state-of-the-art methods.
(Mathematical Geosciences. vol. 56, n° 1874-8961, pp. 949-974, 10/04/2026)
LITIS - App, LITIS, ULH, NU, UNIROUEN, NU, INSA Rouen Normandie, INSA, NU, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Architectures et modélisation géologique 3D des réservoirs argilo-sableux apto-albiens d'Île-de-France (bassin de Paris) pour des applications en géothermie
En Île-de-France, la stratégie énergie-climat prévoit d’augmenter assez significativement la production de chaleur par géothermie à l’horizon 2030. L’aquifère des Sables de l’Albien, situé à environ 650 mètres de profondeur avec des températures de 28 à 38◦C, constitue une cible intéressante pour l’exploitation de la géothermie. En revanche, des retours d'expériences sur cinq opérations sur cet objectif montrent que des problèmes techniques ou aleas altèrent le fonctionnement efficace et durable des doublets geothermiques. En effet, la capacité d’injection est souvent inférieure à celle estimée, ou diminue assez rapidement lors de l’exploitation. La réinjection de particules fines, argileuses, venant du puits producteur, et trop petites pour être filtrées, est l’une des causes considérées pour expliquer cette perte d’injectivité (Maurel et al., 2020 ). Afin d’optimiser le développement de l’aquifère, il convient de mieux caractériser les hétérogénéités de ce réservoir en termes de continuité ou d’épaisseur des niveaux sableux et/ou des niveaux argileux, de minéralogie, de faciès, d’argilosité des sables ou de leur granulométrie. Dans le cadre du projet ANR UPGEO, une base de données rassemblant les logs et données pétrophysiques de puits profonds d’exploration, pétroliers, géothermiques ou encore de stockage de gaz en Île-de-France a été constituée à partir de la Banque du Sous-Sol (BSS) mise à disposition sur InfoTerre par le BRGM, par notre partenaire GEOFLUID, ou encore par STORENGY. Parmi cette base, 149 puits traversant les sables de l’Albien ont été sélectionnés, comprenant au moins une diagraphie (GR) et/ou des descriptions de carottes (forage d’Orsay). Le périmètre d’étude couvre une grande partie de la région Île-de-France, et s’étend du nord de la Seine-Saint-Denis jusqu’au sud de l’Essonne et de la Seine et Marne (110 x 85km). À partir des travaux de Sévenier et Lasseur (2016), ainsi que de la description de carottes de deux forages des sites de stockage de gaz de STORENGY à Crouy-sur-Ourcq et Beynes (longueur totale de 83 m), un réexamen des faciès et séquences stratigraphiques a été réalisé. L’étude détaillée des faciès sur carottes a permis de reconnaître 10 faciès correspondant à 4 environnements de dépôt côtiers avec une dynamique sédimentaire très marquée par les courants tidaux. Sept séquences stratigraphiques de 3ème et 4ème ordre ont ainsi été identifiées et hiérarchisées par l’analyse précise des successions verticales et latérales des faciès sur 20 transects, selon les méthodes de stratigraphie séquentielle. Les Sables de l’Albien sont formés à la base d’une succession estuarienne (Sables Verts), qui se déposent au-dessus de la discordance de l’Aptien supérieur et remplissant des paléo-vallées incisées. Puis un système deltaïque (Sables des Drillons) se met en place, suivi par un système côtier dominé par la houle (Sables de Frécambault) à l’Albien inférieur et moyen. Cette succession traduit une période transgressive après l’émersion d’une grande partie du bassin puis une période de progradation des dépôts côtiers influencés par la marée, avant un ennoiement à l’Albien moyen. Les transects de corrélations permettent d’illustrer la géométrie des corps réservoirs et de retracer les évolutions paléo-environnementales au cours de l’Albien inférieur. A partir de ces interprétations, des cartes paléogéographiques ont été établies et un modèle 3D de faciès centré sur Paris a été réalisé, permettant de visualiser l’architecture des réservoirs. Ce travail a permis d’évaluer les faciès les moins argileux (les sables propres de shoreface), les volumes d’argiles des différents faciès, leur répartition géographique, et leurs épaisseurs. Le modèle géologique 3D habillé en faciès pourra servir de base à la création d’un modèle réservoir afin de réaliser à terme des simulations d’écoulements hydro-thermodynamiques dans le cadre du projet.
(. vol. 83, pp. 210-211/332, 10/04/2026)
GEOPS, INSU - CNRS, CNRS, IFPEN, BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS