Headland Rip Modelling at a Natural Beach under High-Energy Wave Conditions
A XBeach surfbeat model is used to explore the dynamics of natural headland rip circulation under a broad range of incident wave conditions and tide level. The model was calibrated and extensively validated against measurements collected in the vicinity of a 500-m rocky headland. Modelled bulk hydrodynamic quantities were in good agreement with measurements for two wave events during which deflection rips were captured. In particular, the model was able to reproduce the tidal modulation and very-low-frequency fluctuations (≈1 h period) of the deflection rip during the 4-m wave event. For that event, the synoptic flow behaviour shows the large spatial coverage of the rip which extended 1600 m offshore at low tide, when the surf zone limit extends beyond the headland tip. These results emphasize a deflection mechanism different from conceptualised deflection mechanisms based on the boundary length to surf zone width ratio. Further simulations indicate that the adjacent embayment is responsible for the seaward extent of the rip under energetic wave conditions. The present study shows that the circulation patterns along natural rugged coastlines are strongly controlled by the natural variability of the coastal morphology, including headland shape and adjacent embayments, which has implications on headland bypassing expressions.
(Journal of Marine Science and Engineering. vol. 9, n° 2077-1312, pp. 1161, 21/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Spatial distribution of trace elements in the soils of south-western France and identification of natural and anthropogenic sources
The contamination of soils by trace elements is a major concern for soil quality. This study is based on the analysis of 356 samples from the RMQS soil monitoring network to establish the spatial distribution and origin of six trace elements (As, Cd, Cu, Cr, Ni, Pb) in soils of south-western region of France (area of 90,293 km2). An exploratory and multivariate statistical analysis, and geostatistics combined with a geographic information system (GIS) were used to identify and characterize any concentration anomalies in trace elements. For all the trace elements studied, the exploratory analysis shows that there are more anomalies in this region than in the rest of the country. Analysis of the semivariograms shows that the six elements are spatially auto correlated. The spatial structure of As highlights anisotropic behaviour with a direction that corresponds to the gold deposit and mining activities of the region. This indicates a dual origin anthropogenic and geogenic for As. The correlation between Cd and inherent features of calcareous soil (pH, CaCO3 and cation exchange capacity) suggest a mainly geogenic origin for this element; Cd origin is confirmed by its spatial distribution associated with the Jurassic limestone bedrock. The correlations between Cr, Ni and clays highlight a geogenic origin for these elements, as weathered parent material rich in clays is also rich in Cr and Ni. The high Cu concentrations are of anthropogenic origin, linked to viticulture and the spreading of Bordeaux mixture as a fungicide. Locally high Pb concentrations are associated with mining activities and automobile emissions in large cities in the region.
(CATENA. vol. 205, n° 0341-8162, pp. 105446, 21/04/2026)
Bordeaux Sciences Agro, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IPREM, UPPA, INC-CNRS, CNRS
Holocene polynya dynamics and their interaction with oceanic heat transport in northernmost Baffin Bay
Baffin Bay hosts the largest and most productive of the Arctic polynyas: the North Water (NOW). Despite its significance and active role in water mass formation, the history of the NOW beyond the observational era remains poorly known. We reconcile the previously unassessed relationship between long-term NOW dynamics and ocean conditions by applying a multiproxy approach to two marine sediment cores from the region that, together, span the Holocene. Declining influence of Atlantic Water in the NOW is coeval with regional records that indicate the inception of a strong and recurrent polynya from ~ 4400 yrs BP, in line with Neoglacial cooling. During warmer Holocene intervals such as the Roman Warm Period, a weaker NOW is evident, and its reduced capacity to influence bottom ocean conditions facilitated northward penetration of Atlantic Water. Future warming in the Arctic may have negative consequences for this vital biological oasis, with the potential knock-on effect of warm water penetration further north and intensified melt of the marine-terminating glaciers that flank the coast of northwest Greenland.
(Scientific Reports. vol. 11, n° 2045-2322, pp. 10095, 21/04/2026)
GEUS, UNB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, DMI, IGN, UCPH, DGD.REVE, MNHN, LOCEAN-VOG, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, UVSQ, CEA, INSU - CNRS, X, CNES, SU, CNRS, UPCité, ULaval, INSU - CNRS, CNRS, ETH Zürich
Prospective en sciences de la planète et de l’univers
Lancer une prospective scientifique transverse à tout l’Institut national des sciences de l’Univers faisait partie des actions que je m’étais engagées à mener lorsque j’ai présenté ma candidature à la direction au printemps 2018. Ma conviction était, et est toujours, qu’un tel exercice de réflexion collective est primordial en interne à l’INSU pour développer la transversalité et éviter le cloisonnement des disciplines, au sein du CNRS pour renforcer interdisciplinarité et les liens avec les autres instituts, et vis-à-vis de nos partenaires pour partager les grands défis scientifiques et renforcer la stratégie nationale en sciences de l’Univers et de la planète. Si l’idée semble simple, la mise en oeuvre d’une telle prospective nationale pour la premièrefois s’est avérée complexe et je remercie Cyril Moulin d’avoir accepté de la coordonner avec constance et ténacité pendant 2 années : depuis son lancement, à l’occasion d’une réunion des directeurs et directrices d’OSU en octobre 2018, jusqu’au colloque de restitution en novembre 2020, et enfin en finalisant ce document. Comme vous l’imaginez, la crise sanitaire qui a frappé le monde début 2020 et les confinements successifs n’ont pas facilité ce travail basé sur des échanges et des ateliers dont quelques-uns n’ont pas pu se tenir en présentiel. Malgré l’ambition du projet et la complexité du contexte, force est de reconnaître que cette première prospective a été un succès, au-delà même de nos espérances initiales. Elle le doit en premier lieu à l’implication remarquable de vous toutes et tous, chercheurs, ingénieurs et techniciens de l’INSU et de nos partenaires, qui avez répondu présent pourorganiser et participer aux discussions et aux ateliers de chacun des défis identifiés. Je vous en remercie chaleureusement. Je tiens aussi à remercier tout particulièrement les directeurs et directrices des OSU qui ont depuis le début accompagné avec enthousiasme ce projet en animant les discussionsen interne pour faire remonter des défis, puis en organisant et en accueillant les ateliers nationaux de 2-3 jours au sein de leur structure. Ce furent des journées d’échanges denses et excitantes. Je remercie aussi chaleureusement les animateurs scientifiques qui ont construit avec ténacité et conviction le programme des ateliers, coordonné les discussions et synthétisé les échanges pour en tirer les questions prioritaires et proposer des actions à mettreen oeuvre pour renforcer la transversalité au sein de l’INSU et aborder les grands défis scientifiques à venir. Le présent document reprend, nous l’espérons, l’essentiel de foisonnante matière de ces échanges. Un grand merci aussi à l’équipe de direction de l’INSU au sein de laquelle l’enthousiasme et la motivation permanente ont été un grand soutien pour porter cette prospective. Chaque DAS a contribué à cette réussite, c’est ce qui fait aussi la force de notre institut. Mes remerciements vont aussi à la cellule de communication de l’INSU qui nous a permis de tenir un colloque final de grande qualité en virtuel. Je conclurai ces remerciements en saluant le soutien et l’implication des organismes partenaires de l’INSU qui ont accompagné cette prospective pendant les deux ans au sein du comité inter-organismes (CIO). Cet exercice dépassait le cadre de l’INSU et je leur suis infiniment reconnaissant d’y avoir pleinement participé. Cette prospective ouvre des perspectives communes qui, j’en suis persuadé, vont nous donner un cadre de collaboration renouvelé pour relever ensemble les défis qui nous attendent en sciences de la planète et de l’Univers.
(21/04/2026)
INSU - CNRS, LAM, AMU, INSU - CNRS, CNES, CNRS, IPAG, INSU - CNRS, CNES, CNRS, Fédération OSUG, UGA, IRAP, UT3, Comue de Toulouse, INSU - CNRS, CNRS, GEOAZUR 7329, INSU - CNRS, UniCA, CNRS, IRD [Occitanie], UniCA, LMV, IRD, INSU - CNRS, CNRS, UCA, LOCEAN-NEMO R&D, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, UVSQ, CEA, INSU - CNRS, X, CNES, SU, CNRS, UPCité, iSTeP, INSU - CNRS, SU, CNRS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, ICOS-RAMCES, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, LOPS, IRD, IFREMER, INSU - CNRS, UBO EPE, CNRS, IGE, IRD, INSU - CNRS, CNRS, Fédération OSUG, UGA, Grenoble INP, UGA, LCE, CNRS, UFC, UBFC, LGGE, INSU - CNRS, CNRS, OSUG, Grenoble INP, INSU - CNRS, IRSTEA, USMB [Université de Savoie] [Université de Chambéry], CNRS, UGA [2016-2019], IPEV, M.E.N.E.S.R., ULaval, INSU - CNRS, CNRS, AMURE, IRD, IFREMER, UBO EPE, CNRS, UBO EPE, IUEM, IRD, INSU - CNRS, UBO EPE, CNRS, UR ETTIS, INRAE, IPREM, UPPA, INC-CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, OCEANIS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, ObAS, UNISTRA, INSU - CNRS, CNRS, EOST, UNISTRA, INSU - CNRS, CNRS, ITES, ENGEES, UNISTRA, INSU - CNRS, CNRS, UNISTRA, ISTerre, IRD, INSU - CNRS, USMB [Université de Savoie] [Université de Chambéry], CNRS, Fédération OSUG, UGA
Geomorphology of a modern carbonate slope system and associated sedimentary processes: Example of the giant Great Abaco Canyon, Bahamas
The large acoustic data set acquired during the Carambar cruises is composed of high resolution bathymetry, backscatter data and very-high resolution seismic lines which allow for an overview of the morphology and sediment transfer processes from the shallow upper slope to the abyssal plain of a modern carbonate system: the north-eastern slope of the Little Bahama Bank. Surficial distribution of the acoustic facies and echofacies reflects a wide variety of sedimentary processes along and across the slope. The western sector of the Little Bahama Bank is dominated by depositional processes whereas its eastern sector, which is incised in the lower slope by giant canyons, is affected by erosion and bypass processes. Datasets suggest that currents play an important role both in along-slope sedimentary processes and in the abyssal plain. The Antilles Current appears to affect a large part of the middle and lower slopes. The absence of sizeable present-day channel/levee complexes or lobes at the mouth of the canyon - revealed by the bathymetric map - indicates that the southward flowing Deep Western Boundary Current influences modern abyssal sediment deposition. Based on depositional processes and indicators of canyon maturity observed in facies distribution, the current study proposes that differential subsidence affects the eastern versus western part of the bank. The morphology of the Great Abaco Canyon and Little Abaco Canyon, which extend parallel to the platform, and the Little Bahama Bank slope appears to be related to the Great Abaco Fracture Zone.
(Sedimentology. vol. 68, n° 0037-0746, pp. 266-293, 21/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
A first assessment of organic carbon burial in the West Gironde Mud Patch (Bay of Biscay)
On the Bay of Biscay continental shelf, there are several mid-shelf mud patches including La Grande Vasière to the north, the West Gironde Mud Patch (WGMP) off the Gironde estuary and the Basque Mud Patch close to the Spanish border. In general, these deposits are several meters thick and cover coarser substrate. Questions remain about their storage capability for fine particles and carbon. This work investigates the sedimentation of the WGMP in order to develop a first estimate of organic carbon (OC) burial. Interface sediment cores were collected at nine stations along two cross-shelf transects in October-November 2016. X-radiograph imaging and grain-size analyses were used to characterize sedimentary structures. 210 Pb xs depth profiles were established to calculate sediment (SAR) and mass (MAR) accumulation rates. Sedimentary structures indicate episodic sandy inputs overlying older deposits at proximal sites, and relatively continuous sedimentation at seaward locations. On the outer-central portion of the northern transect, a maximum SAR (0.47 cm yr − 1) was observed, suggesting a depocenter. On the southern transect, excluding two stations where sedimentary inputs appear massive but sporadic, the SARs are lower (<0.3 cm yr − 1). Quantitative estimates of OC burial rates increase seaward with a maximum of 45 gC m − 2 yr − 1. To evaluate carbon loading independent of grain-size variability, OC values were normalized to surface area of sediments (SA). Interestingly, a qualitative comparison of OC burial efficiencies using the OC/SA ratio highlights three groups of sites (low, medium and relatively high OC burial efficiency) which are likely related both to different sedimentary environments and variable deposition conditions linked to local environmental conditions and depth. This work highlights the likely control of hydrodynamic intensity and sedimentary inputs on the amount of OC stored in the WGMP sediments.
(Continental Shelf Research. vol. 221, n° 0278-4343, pp. 104419, 21/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, URI
A Bayesian network approach to modelling rip-current drownings and shore-break wave injuries
Abstract. A Bayesian network (BN) approach is used to model and predict shore-break-related injuries and rip-current drowning incidents based on detailed environmental conditions (wave, tide, weather, beach morphology) on the high-energy Gironde coast, southwest France. Six years (2011–2017) of boreal summer (15 June–15 September) surf zone injuries (SZIs) were analysed, comprising 442 (fatal and non-fatal) drownings caused by rip currents and 715 injuries caused by shore-break waves. Environmental conditions at the time of the SZIs were used to train two separate Bayesian networks (BNs), one for rip-current drownings and the other one for shore-break wave injuries. Each BN included two so-called “hidden” exposure and hazard variables, which are not observed yet interact with several of the observed (environmental) variables, which in turn limit the number of BN edges. Both BNs were tested for varying complexity using K-fold cross-validation based on multiple performance metrics. Results show a poor to fair predictive ability of the models according to the different metrics. Shore-break-related injuries appear more predictable than rip-current drowning incidents using the selected predictors within a BN, as the shore-break BN systematically performed better than the rip-current BN. Sensitivity and scenario analyses were performed to address the influence of environmental data variables and their interactions on exposure, hazard and resulting life risk. Most of our findings are in line with earlier SZI and physical hazard-based work; that is, more SZIs are observed for warm sunny days with light winds; long-period waves, with specifically more shore-break-related injuries at high tide and for steep beach profiles; and more rip-current drownings near low tide with near-shore-normal wave incidence and strongly alongshore non-uniform surf zone morphology. The BNs also provided fresh insight, showing that rip-current drowning risk is approximately equally distributed between exposure (variance reduction Vr=14.4 %) and hazard (Vr=17.4 %), while exposure of water user to shore-break waves is much more important (Vr=23.5 %) than the hazard (Vr=10.9 %). Large surf is found to decrease beachgoer exposure to shore-break hazard, while this is not observed for rip currents. Rapid change in tide elevation during days with large tidal range was also found to result in more drowning incidents. We advocate that such BNs, providing a better understanding of hazard, exposure and life risk, can be developed to improve public safety awareness campaigns, in parallel with the development of more skilful risk predictors to anticipate high-life-risk days.
(Natural Hazards and Earth System Sciences. vol. 21, n° 1561-8633, pp. 2075-2091, 21/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BPH, UB, INSERM
Response of water-exchange capacity to human interventions in Jiaozhou Bay, China
Intensive anthropogenic activities, land reclamation, a cross-bay bridge construction, and the correction of Red Island have significantly changed the topography of Jiaozhou Bay (JZB) in northern China over the last decades. To quantify the effects of these modifications on the water-exchange capacity of the bay, the Finite Volume Community Ocean Model was used to calculate basin, regional and local residence time (RT) in the years 1935, 1966, 1986, 2000, 2008, and 2013, covering the periods of significant land reclamation. The bridge construction and a government plan to restore Red Island were also included in additional modelling scenarios. The regional RT increased significantly between 1935 and 1986, by 77% in the northeast, 40% in the west and 56% in the north-bridge regions, concurrent with the largest land reclamation. The regional RT continued to increase from 1986 to 2000 in the northeast and north-bridge regions but decreased slightly from 2000. These patterns can be explained by the general decreasing trend of the tidal prism from 1935 to 2000, up to 66% in the northeast region. A significant decrease in residual currents from 1935 to 1966 probably also contributed to explain this trend. The bridge construction had only a limited effect on regional RT. The restoration of Red Island would have reduced the regional RT in the northeast region from 83 to 60 days. The simulation of tracer transport, and therefore calculation of local RT, was found to be sensitive to the scheme used to formulate the horizontal diffusion coefficient, which should be taking into account when comparing results from different model configurations.
(Estuarine, Coastal and Shelf Science. vol. 249, n° 0272-7714, pp. 107088, 21/04/2026)
UNSW, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Fluorescence analysis allows to predict the oxidative capacity of humic quinones in dissolved organic matter: implication for pollutant degradation
Dissolved organic matter (DOM) controls the degradation and sequestration of aquatic pollutants and, in turn, water quality. In particular, pollutant degradation is performed by oxidant species that are generated by exposure of DOM to solar light, yet, since DOM is a very complex mixture of poorly known substances, the relationships between potential oxidant precursors in DOM and their oxydative capacity is poorly known. Here, we hypothesized that production of oxidant species could be predicted using fluorescence analysis. We analysed water samples from an alluvial plain by fluorescence spectroscopy; the three-dimensional spectra were then decomposed into seven individual components using a multi-way algorithm. Components include a protein-like fluorophore, e.g. tryptophan-like and tyrosine-like, three humic fluorophores, 2-naphthoxyacetic acid, and a by-product. We compared component levels with the ability of water samples to generate reactive species under solar light. The results show a strong correlation between reactive species production and the intensity of two humic-like fluorophores assigned to reduced quinones. Monitoring these fluorophores should thus allow to predict the ability of DOM degradation of pollutants in surface waters.
(Environmental Chemistry Letters. vol. 19, n° 1610-3653, pp. 1857-1863, 21/04/2026)
ICCF, SIGMA Clermont, INC-CNRS, UCA [2017-2020], CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GEOLAB, UBP, IR SHS UNILIM, UNILIM, UCA [2017-2020], CNRS, UCA
Generational effects of a chronic exposure to a low environmentally relevant concentration of glyphosate on rainbow trout, Oncorhynchus mykiss
In the past few decades, glyphosate became the most used herbicide substance worldwide. As a result, the substance is ubiquitous in surface waters. Concerns have been raised about its ecotoxicological impact, but little is known about its generational toxicity. In this study, we investigate the impact of an environmentally relevant concentration of glyphosate and its co-formulants on an F2 generation issued from exposed generations F0 and F1. Trans, inter and multigenerational toxicity of 1 μg L−1 of the active substance was evaluated on early stages of development and juvenile rainbow trout (Oncorhynchus mykiss) using different molecular, biochemical, immuno-hematologic, and biometric parameters, behavior analysis, and a viral challenge. Reproductive parameters of generation F1 were not affected. However, developmental toxicity in generation F2 due to glyphosate alone or co-formulated was observed with head size changes (e.g. head surface up to +10%), and metabolic disruptions (e.g. 35% reduction in cytochrome-c-oxidase). Moreover, larvae exposed transgenerationally to Viaglif and intergenerationally to glyphosate and Roundup presented a reduced response to light, potentially indicating altered escape behavior. Overall methylation was, however, not altered and further experiments using gene-specific DNA metylation analyses are required. After several months, biochemical parameters measured in juvenile fish were no longer impacted, only intergenerational exposure to glyphosate drastically increased the susceptibility of rainbow trout to hematopoietic necrosis virus. This result might be due to a lower antibody response in exposed fish. In conclusion, our results show that generational exposure to glyphosate induces developmental toxicity and increases viral susceptibility. Co-formulants present in glyphosate-based herbicides can modulate the toxicity of the active substance. Further investigations are required to study the specific mechanisms of transmission but our results suggest that both non-genetic mechanisms and exposure during germinal stage could be involved.
(Science of the Total Environment. vol. 801, n° 0048-9697, pp. 149462, 21/04/2026)
ANSES, UBO EPE, VIMEP, ANSES, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS