Contaminant storage in depositional environments induced by river engineering in the upper Seine Estuary (France)
The extensive engineering of the Seine estuary upstream of Rouen (France) since the 1950s to support the growth of river transport has led to a significant recalibration of the riverbed. These morphological changes have enhanced sedimentation in sheltered areas, which are known to trap contaminants from upstream anthropized watersheds. As part of the DESTOX project, five depositional environments, constructed between 1953 and 1981, and each of them storing up to 1.105 m3 of sediment, are being investigated. Ten sediment cores were collected from a mudflat embanked in 1972. Concentrations of PAHs, PCBs, alkanes, metals and 137Cs activities are being measured along one of the cores (1.62 m). PAH concentrations will be estimated on the 9 other cores using hyperspectral imaging (following the method from Jacq et al., 2024) and interpolated to assess the PAH stock at the site scale. Preliminary results show PCB concentrations of up to 3.9 ± 0.4 mg kg-1, which is 50 times higher than the average concentration measured in suspended particulate matters currently circulating in the Seine Estuary. The aim of this work is to measure the extent of contamination in sediment stocks in the upper estuary in order to better understand the potential risk associated with the remobilization of these sediments. Such remobilization could be triggered by extreme hydrological events, restoration work, sea-level rise or other processes.
(30/06/2025)
M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GIP-Seine-Aval, Cerema, LEHNA, UCBL, ENTPE, CNRS
Measuring Ocean Surface Waves
Propagating waves on the surface of the ocean can be represented as a stochastic process, whose statistics are characterized by a spectrum. Measuring the wave spectrum, and quantities derived from the spectrum, are reviewed here. Observation begins by sensing some property of the sea surface over space and/or time. Visual observations, collected routinely since the mid 18th century, comprise the longerest running wave record. Measurement methods in the nearshore are advancing, including traditional methods using pressure and acoustic sensing, but also newer methods such as distributed acoustic sensing and lidar. Detailed, small scale wave physics can now be explored with measurement techniques using light, including stereo-imaging and polarimatry. The decrease in size, cost, and power consumption of microelectronics has propagated through to ocean wave instrumentation, most notably in wave buoys. Global networks of freely drifting miniature wave buoys offer novel observational power. Remote sensing techniques based on radar and lidar continue to evolve, and are widely deployed from land and on ships, aircraft, autonomous vehicles, and satellites. Spaceborne altimeters form one of the most important records of wave height, and a suite of suite of new spaceborne sensors are observing directional spectra across the globe with sampling akin to traditional altimetry. Aircraft and autonomous systems are providing strategic sampling capabilities, whether for detailed process studies or accessing extreme storm environments. The quality and quantity of ocean wave measurements has never been greater. This review will help you make sense of it all.
(30/06/2025)
USACE, UPR-M, UC San Diego, UC, ISMAR, CNR, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, MET, SIO - UC San Diego, UC San Diego, UC, OSU, MPL, SIO - UC San Diego, UC San Diego, UC, SIO, RAS, LATMOS, UVSQ, INSU - CNRS, SU, CNRS, NTU, UNH, RSMAS, LIENSs, INSU - CNRS, ULR, CNRS, UTokyo, DGFI-TUM, TUM, Rutgers, WHOI, JAMSTEC, NOC, KIOST, LDEO, JISAO, PMEL, NOAA
Chronostratigraphy of the mixed Upper Cretaceous deposits at the northern margin of the Arabian Plate (Jordan)
This study provides an updated chronostratigraphy to the biozone level, integrating nannofossils, ammonites, benthic foraminifera, and Sr isotopes, for the mixed carbonate-siliciclastic-phosphatic-organic-rich Upper Cretaceous succession in south-central Jordan based on two well-exposed sections of 635 m and 712 m thick and located 100 km apart. Seven stratigraphic hiatuses have been identified, and significant changes in sedimentation rate are observed for this lithologically diverse stratigraphic succession. Well-dated surfaces are identified and provide unique and high-resolution calibration points for tectonic and paleoceanographically induced sedimentary system changes affecting the southeastern Neo-Tethys margin. The studied sections are located on the northern Arabian Plate continental shelf and contain a rich calcareous nannofossil assemblage that increases upwards in abundance and diversity. Ammonoids and benthic foraminifera helped to refine the Cenomanian and Turonian shallow water carbonate interval of the Ajlun Group. In the overlying Belqa Group, the integration of 87Sr/86Sr dating provided essential age constraints for the fossil barren shallow-water siliciclastic deposits of the Coniacian and Santonian, while it also provided calibration points for the nannofossil-rich Campanian and Maastrichtian strata. Age-depth and Bayesian statistics modeling constrain the duration and positions of the stratigraphic hiatuses, which show a consistent pattern between the 100 km spaced sections and have been correlated to the neighboring countries.
(Newsletters on Stratigraphy. vol. 58, n° 0078-0421, pp. 161-201, 21/06/2025)
KAUST, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BGS
Elucidation of the life cycle of the trematode Curtuteria arguinae (Digenea: Himasthlidae), using environmental DNA detection methods
Abstract Detection approaches based on environmental DNA (eDNA) are widely used for free-living species but remain underutilized for parasite species. This study applies eDNA detection methods to elucidate the life cycle of the trematode Curtuteria arguinae , which infects the socioeconomically and ecologically important edible cockle ( Cerastoderma edule ) as its second intermediate host along the northeastern Atlantic coast, including Arcachon Bay, France. The first intermediate and definitive hosts remained unknown. To identify these hosts – presumed to be a gastropod and a shorebird – we developed a quantitative PCR (qPCR)-based eDNA approach targeting partial cox1 and SSU gene regions of C. arguinae . We tested for C. arguinae eDNA presence in water samples containing separately five dominant gastropod species and fecal samples from known cockle predators, the European oystercatcher ( Haematopus ostralegus ) and gulls ( Larus spp.), collected in Arcachon Bay. C. arguinae eDNA was only detected in water containing the needle snail ( Bittium reticulatum ), with cercarial emergence confirming infection in 1.6% of individual hosts. Morphological analysis of the cercarial and metacercarial stages revealed variability in collar spine visibility. Additionally, C. arguinae was detected by qPCR in 42% of oystercatcher feces and no gull feces, suggesting oystercatchers are the definitive host. This study is the first to elucidate the complete life cycle of C. arguinae , identifying B. reticulatum as its first intermediate host and H. ostralegus as its definitive host. Our findings highlight the potential of eDNA approaches for resolving parasite life cycles and enabling advances in ecological research on C. arguinae .
(Parasitology. vol. 152, n° 0031-1820, pp. 704-714, 18/06/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ECOMAP, AD2M, SU, CNRS, SBR, SU, CNRS, SBR, SU, CNRS, AD2M, SBR, UPMC, CNRS, UPMC, CNRS, IRSTEA
An extreme drought and heatwave event led to collapse of facilitation by metallophyte species in metalliferous ecosystems
Aims: Recent studies have highlighted the importance of plant facilitation in metal-rich environments. Among the positive effects of metallophyte nurse plants, the improvement of microclimatic conditions for neighboring plants has been reported. Here, we aim to assess if plant facilitation persists with the additional stress caused by the extreme drought and heatwave that occurred in 2022 in the northern hemisphere. Methods: We conducted four transplant experiments with grass species placing them under nurse plants or in areas where nurse plants have been removed. These experiments were carried out along soil pollution gradients at various sites and elevation in a former mining valley in the French Pyrenees. The first three experiments were conducted in 2020 and 2021, while the fourth was done in 2022. Each year, transplant survival was monitored at the end of the growing season. Results: The 2020 and 2021 experiments confirmed the increase of positive interactions as metal-pollution increased, aligning with the Stress Gradient Hypothesis. However, during the extreme year, facilitation disappeared, likely because dominant nurse plants were weakened and no longer influenced neighboring plants. Conclusions: Metallophyte species in temperate regions are not necessarily drought-tolerant and are certainly affected by severe drought and heatwaves. This additional intense stress, in habitats already challenged by metal presence in soils, likely compromised their ability to improve micro-climatic conditions for neighboring plants. This collapse of facilitative effects was observed at both low- and high-elevation sites, highlighting the strong impact of such meteorological event in metalliferous ecosystems.
(Plant and Soil, n° 0032-079X, 12/06/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BRGM, UMR ISPA, Bordeaux Sciences Agro, INRAE
Influence of meteo-marine forcings on groundwater level fluctuations of a coastal multi layer aquifer
A multi-layered aquifer made up of alluvial formations from the Quaternary, overlying levels of Pliocene sands and clays is located beneath the Roussillon plain (Perpignan, France). Covering an area of 800 km² and up to 300 m thick on land, this aquifer extends several dozen kilometres beneath the Mediterranean Sea. It contains a freshwater resource which, at a greater or lesser distance from the shoreline, is likely to be mixed with seawater. A hydrogeophysical observatory (Dem'Mer) has been set up along the coastline for monitoring the piezometric and physicochemical (conductivity, temperature) behavior of the groundwater flowing through the various permeable levels described within this multi-layer aquifer. The time series of groundwater levels obtained from this observatory for several years have been processed using spectral analysis to explore the seasonal to daily influence of meteomarine forcings (seawater level, tides, storms) on groundwater flows. Complementary, crosscorrelation and coherence analyses have been performed to identify how the different signals are organised over time. This work provides field evidence of the influence of storm waves forces at sea bottom, water level at the shoreline and tide on the piezometric fluctuations in the aquifer nearby the coast. The results obtained constitute constraints that can be incorporated into the modelling work currently underway on this aquifer.
(02/06/2025)
BRGM, UM, UMR G-EAU, Cirad, BRGM, IRD, INRAE, Institut Agro, UM, INSU - CNRS, CNRS, UA, UM, SMNPR, UNINE, UniFE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UB
Numerical investigation of seasonal wind-wave responses to severe seagrass decline in a coastal lagoon
The intensification of environmental stressors and anthropogenic pressures has resulted in significant seagrass loss worldwide, reducing the capacity of vegetation to damp hydrodynamic energy. While the broad-scale impact of seagrass decline on wind waves has been partially investigated in coastal lagoons, the role of seasonal variations in seagrass characteristics in influencing these responses remains not fully understood. We propose to explore the seagrass-wave interaction through the implementation of a novel coupled wave-flow-vegetation model, which considers deflected canopy height in WAVEWATCH-III, and applied to the Arcachon lagoon. We perform a scenario analysis using different wind conditions and various maps of seagrass coverage (from 1989 to 2016) to provide new insights into how seasonality affects wind wave responses to Zostera noltei decline. Our results reveal that during the summer, when seagrasses are fully developed, seagrass decline significantly reduces the ability of Z. noltei to dissipate wave energy, leading to a wave height increase (reaching 30 %, for H m0 between 0.05 m and 0.35 m) in the areas where seagrass coverage is most reduced. However, during the winter, when canopy height and density are low, no significant changes in wave dissipation are observed due to Z. noltei decline. This study also shows that modifications of the ambient current within the canopy further decreases the capacity of Z. noltei to attenuate waves, as the intensification of flow conditions due to seagrass decline reduces canopy height
(Coastal Engineering. vol. 201, n° 0378-3839, pp. 104796, 01/06/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LERAR, COAST, IFREMER, BRGM
Field measurements of wave and flow dynamics along a high-energy meso-macrotidal coast adjacent to a large estuary mouth
The North-Médoc coast, located to the south of the Gironde estuary, exhibits complex hydrodynamic conditions driven by high-energy incident waves and large tides, which are influenced by large-scale rocky outcrops, shoals, and tidal channels on the inner shelf. These wave- and tide-driven hydrodynamics result in rapid morphological changes, with shoreline erosion peaking locally at 5 m/year. In autumn 2022, an intensive two-week field campaign was conducted along three cross-shore transects distributed across the North-Médoc coast to, for the first time, document and analyze the hydrodynamics in this area. The campaign involved collecting measurements of waves and currents across both the inner shelf and nearshore regions, using six current profilers and 13 pressure sensors. Tides were found to predominantly modulate wave transformation and flow in both the nearshore and inner shelf regions of the North-Médoc coast. Strong alongshore currents were measured across the entire study site, increasing southward, which is linked to the overall morphology of a tidal channel. Tidal currents are flood-dominated in the northern part and ebb-dominated in the southern and central parts of the study area. Total currents and wave heights are modulated by tidal elevation, with, for example, increased wave height at the coast during higher tide levels. Nearshore waves, which undergo complex transformation across the inner shelf, such as wave refraction over shoals and rocky outcrops, also drive longshore currents in the surf zone, superimposed on the tidal current. These conditions result in a strong, net, northeastward longshore current, even during low-energy wave conditions. These observations provide new insights into the hydrodynamics of this rapidly evolving coastline and establish a comprehensive dataset that will be crucial for the development and validation of process-based and reduced-complexity models in this region
(Estuarine, Coastal and Shelf Science. vol. 317, n° 0272-7714, pp. 109205, 01/06/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BRGM, LIENSs, INSU - CNRS, ULR, CNRS
Seamless nearshore topo-bathymetry reconstruction from lidar scanners: A Proof-of-Concept based on a dedicated field experiment at Duck, NC
Accurate observations of the nearshore bathymetry, including within the breaking wave region, are critical for the prediction of coastal hazards, and improved understanding of sandy beach morphological response to storms. In this paper, we implement the recent Boussinesq theory-based depth inversion methodology of Martins et al. (Geophys. Res. Lett., 50 (2023), Article e2022GL100498) to single-and multibeam lidar datasets collected during a dedicated field experiment on a sandy Atlantic Ocean beach near Duck, North Carolina. Compared with common approaches based on passive remote sensing technology (e.g., optical imagery), lidar scanners present several key advantages, including the capacity to directly measure the beach topography, waveforms and the cross-shore variations in mean water levels due to wave action (e.g., the wave setup), leading to the seamless reconstruction of a vertically-referenced beach topo-bathymetry. Given the potentially gappy nature of lidar data, particular attention is paid to the robust computation of surface elevation spectral and bispectral quantities, which are at the base of the proposed non-linear depth inversion methodology. Promising results on the final topo/bathymetry are obtained under contrasting wave conditions in terms of non-linearity and peak period, with an overall root-mean square error below 0.3 m obtained along a cross-shore transect covering both shoaling and breaking wave conditions. The accuracy of the final bathymetry in the shoaling and outer surf regions is generally found to be excellent, with similar skills as previously obtained in laboratory settings (relative error < 10 -15%). Under the most energetic conditions, an underestimation of the wave phase velocity spectra is observed within the surf zone with all theoretical frameworks, potentially owing to surf zone vortical motions not yet accounted for in the present methodology. This underestimation of the wave phase velocities results in a relatively large overestimation of the mean water depth, between 30% to 100% depending on the theoretical framework. With the methodology described herein, lidars bring new perspectives for seamlessly mapping the nearshore topo/bathymetry, and its temporal evolution across a wide range of scales. Although currently limited to a single cross-shore transect, we believe that opportunities exist to integrate multiple remote sensors, which could address individual sensor limitations, such as coverage (lidar) or the incapacity to directly measure waveforms (optical imagery).
(Coastal Engineering. vol. 199, n° 0378-3839, pp. 104748, 01/06/2025)
LIENSs, INSU - CNRS, ULR, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
PBK-TD modelling of the gonadotropic axis: Case study with two azole fungicides in female zebrafish
Endocrine disruptors (EDs) can disrupt the gonadotropic axis, which consists of the Hypothalamus-Pituitary-Gonads (HPG), notably by altering aromatase (cyp19a), a key enzyme regulating the endocrine system and reproductive function in fish. The effects of EDs can be predicted by integrating both toxicokinetic (TK) and toxicodynamic (TD) processes in order to relate adverse outcomes to external exposures. In this study, we developed a physiologically based kinetic-toxicodynamic model to simulate the disruption of the HPG axis (PBK-TD, hereafter named PBK-HPG) in female zebrafish exposed to either of two aromatase inhibitors, imazalil or prochloraz. The model was calibrated using Bayesian methods and supported by novel experimental data, including measurements of vitellogenin, 17β-estradiol, and 11-ketotestosterone levels, along with in vivo monitoring of the cyp19a1a gene in transgenic cyp19a1a-GFP ebrafish. Seamless integration of a PBK model within a TD model of the HPG-axis, provided the link between external exposure and internal levels of imazalil and prochloraz in key organs, allowing for mechanistic predictions of their inhibitory effects on gonadal aromatase. Our PBK-HPG model accurately predicted both baseline homeostasis and the effects of aromatase inhibition, with all endocrine endpoints including reproductive disruption, i.e., decreased egg production, falling within a twofold range of both experimental and literature data. Therefore, our PBK-HPG model could further support the development of a mechanistic qAOP with TK considerations. The model offers significant potential for improving environmental risk assessments of EDs and possibly other stressors across species.
(Aquatic Toxicology. vol. 283, n° 0166-445X, pp. 107337, 01/06/2025)
INERIS, SEBIO, INERIS, URCA, ULH, NU, URCA, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS