Tidal Pumping, Alkalinity Production and Export: An Overlooked Carbon Sequestration Process in Salt Marshes
(03/09/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Semi-empirical forecast modelling of rip-current and shore-break wave hazards
Sandy beaches are highly attractive but also potentially dangerous environments for those entering the water as they can be exposed to physical hazards in the surf zone. The most severe and widespread natural bathing hazards on beaches are rip currents and shore-break waves, which form under different wave, tide, and morphological conditions. This paper introduces two new, simple semiempirical rip-current and shore-break wave hazard forecast models. These physics-informed models, which depend on a limited number of free parameters, can be used to compute the time evolution of the rip-current flow speed V and shore-break wave energy E sb . These models are applied to a high-energy mesotidal-macrotidal beach, La Lette Blanche, in southwest France, where intense rip-currents and shore-break wave hazards co-exist. Hourly lifeguardperceived hazards collected during patrolling hours (from 11:00 a.m. to 07:00 p.m. LT (UTC+2)) during July and August of 2022 are used to calibrate the two models. These data are also used to transform V and E sb into a five-level scale from 0 (no hazard) to 4 (hazard maximised). The model accurately predicts rip-current and shore-break wave hazard levels, including their modulation by tide elevation and incident wave conditions, opening new perspectives for forecasting multiple surf-zone hazards on sandy beaches. In addition, daily-mean hazard forecasts demonstrate even greater predictive skill, which is important for conveying straightforward messages to the general public and lifeguard managers. The approach presented here only requires a limited number of beach morphology metrics and allows for the prediction of surf-zone hazards on beaches where wave and tide forecasts are available.
(Natural Hazards and Earth System Sciences. vol. 25, n° 1561-8633, pp. 2379–2397, 03/09/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR ETTIS, INRAE, SMGBL, UR EABX, INRAE
Use of solute concentration gradients in the benthic boundary layer to highlight sediment source-sink dynamics: a non-invasive in situ study
Oxygen, nutrients, and pollutants fluxes at the sediment-water interface are involved in the water quality and ecological status of shallow coastal environments. The short-term variabilities of these fluxes, in response to hydrodynamic and benthic biogeochemical processes in the field, make it difficult to assess the net balance of these fluxes. Here we evaluate the ability of using concentration gradients in the benthic boundary layer to better understand temporal variations in these fluxes. Three shallow Mediterranean coastal lagoons (Berre, Thau and Prévost lagoons), affected by deoxygenation events and depicting contrasting water quality status, were investigated. A Benthic Oxygen Gradient Observatory System (BOGOS) was set-up and deployed for two weeks in each lagoon to obtain continuous oxygen gradient time-series. In addition, concentration gradients of nutrients (Si, NH4+, PO43−) and trace elements (Fe, Mn, Co, As, Cu, Mo, MeHg) were obtained using a specifically dedicated benthic water sampler (SUSANE) deployed under contrasting oxygenation conditions (oxic, hypoxic, anoxic, euxinic) and diurnal cycles (day and night). The results enabled us firstly to better define the limits of applying the gradient method in shallow coastal areas, considering environmental conditions (water stratification, intense water mixing, low flux intensity) as well as technical limitations (concentration uncertainty). This approach then allowed to accurately capture contrasted benthic oxygen dynamics: diurnal cycles in sediments colonized by macrophytes in Prévost and Thau lagoons, and a dominant high oxygen demand in bare sediments in Berre lagoon. Benthic solute gradients in Berre lagoon indicated release of nutrients from the sediment under normoxic conditions after a long-term anoxic event, as well as release of dissolved Mn, Fe, As and Co under anoxic conditions. Under euxinic conditions, gradients reversed for most trace elements that were trapped in sediment due to (co)precipitation with sulfide minerals, while nutrient gradients indicated continuing sizeable releases to the water column. The benthic concentration gradient approach can thus be seen as a promising approach in assessing the dynamics of benthic fluxes at an appropriate time scale in highly dynamic shallow coastal lagoons. This effort should be completed by vertical turbulent diffusivity measurements, to obtain time series of turbulent fluxes of various solutes.
(Estuarine, Coastal and Shelf Science. vol. 323, n° 0272-7714, pp. 109432, 03/09/2026)
CHROME, UNIMES, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UAG, INSU - CNRS, UM, CNRS, CEREGE, IRD, AMU, CdF (institution), INSU - CNRS, CNRS, INRAE, UMR Marbec - Station Sète, UMR MARBEC, IRD, IFREMER, CNRS, UM, MIO, IRD, AMU, INSU - CNRS, UTLN, CNRS, LCE, AMU, INC-CNRS, CNRS, HSM, IRD, INSU - CNRS, CNRS, UM, CCEM, IFREMER
Key concepts and a world‐wide look at plant recruitment networks
Plant–plant interactions are major determinants of the dynamics of terrestrial ecosystems. There is a long tradition in the study of these interactions, their mechanisms and their consequences using experimental, observational and theoretical approaches. Empirical studies overwhelmingly focus at the level of species pairs or small sets of species. Although empirical data on these interactions at the community level are scarce, such studies have gained pace in the last decade. Studying plant–plant interactions at the community level requires knowledge of which species interact with which others, so an ecological networks approach must be incorporated into the basic toolbox of plant community ecology. The concept of recruitment networks (RNs) provides an integrative framework and new insights for many topics in the field of plant community ecology. RNs synthesise the set of canopy–recruit interactions in a local plant assemblage. Canopy–recruit interactions describe which (“canopy”) species allow the recruitment of other species in their vicinity and how. Here we critically review basic concepts of ecological network theory as they apply to RNs. We use RecruitNet, a recently published worldwide data set of canopy–recruit interactions, to describe RN patterns emerging at the interaction, species, and community levels, and relate them to different abiotic gradients. Our results show that RNs can be sampled with high accuracy. The studies included in RecruitNet show a very high mean network completeness (95%), indicating that undetected canopy–recruit pairs must be few and occur very infrequently. Across 351,064 canopy–recruit pairs analysed, the effect of the interaction on recruitment was neutral in an average of 69% of the interactions per community, but the remaining interactions were positive (i.e. facilitative) five times more often than negative (i.e. competitive), and positive interactions had twice the strength of negative ones. Moreover, the frequency and strength of facilitation increases along a climatic aridity gradient worldwide, so the demography of plant communities is increasingly strongly dependent on facilitation as aridity increases. At network level, species can be ascribed to four functional types depending on their position in the network: core, satellite, strict transients and disturbance‐dependent transients. This functional structure can allow a rough estimation of which species are more likely to persist. In RecruitNet communities, this functional structure most often departs from random null model expectation and could allow on average the persistence of 77% of the species in a local community. The functional structure of RNs also varies along the aridity gradient, but differently in shrubland than in forest communities. This variation suggests an increase in the probability of species persistence with aridity in forests, while such probability remains roughly constant along the gradient in shrublands. The different functional structure of RNs between forests and shrublands could contribute to explaining their co‐occurrence as alternative stable states of the vegetation under the same climatic conditions. This review is not exhaustive of all the topics that can be addressed using the framework of RNs, but instead aims to present some of the interesting insights that it can bring to the field of plant community ecology.
(Biological Reviews. vol. 100, n° 1464-7931, pp. 1127-1151, 03/09/2026)
UJA, NEOLAiA, IISTA-CEAMA, UGR, CIDE, CSIC, UNCOMA, UCA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, SYSU, CEFE, EPHE, PSL, CNRS, IRD [Occitanie], IRD, INRAE, Institut Agro, UM, UMPV
Rapport intermédiaire du projet Vigie-Lacs
L’objectif du projet est d’acquérir des connaissances scientifiques indispensables à la préservation des communautés de plantes aquatiques des lacs et étangs du littoral aquitain fortement menacées par les activités humaines et le changement climatique. Ce projet pluridisciplinaire fait appel à plusieurs domaines scientifiques complémentaires, telles que l’écologie des communautés, l’autécologie, la biogéochimie, les biostatistiques, la génétique ou encore l’hydrogéologie.
(pp. 24, 03/09/2026)
UR EABX, INRAE, ECLA, USMB [Université de Savoie] [Université de Chambéry], INRAE, OFB, BioGeCo, UB, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Digital PCR (dPCR) vs. Quantitative PCR (qPCR) approaches for quantification of two Perkinsus species within clam tissue samples
The parasite Perkinsus olseni (Perkinsea, Alveolata), the etiological agent of Perkinsosis, infects a wide range of bivalves and gastropods, including clams, particularly in Europe. This parasite coexists in sympatry with another Perkinsus species, P. chesapeaki, which, as opposed to P. olseni, has not been directly associated to mortality events. Accurate detection and quantification of Perkinsus infections, even at low infection intensities, are crucial for monitoring clam population health and assessing risks associated with emerging diseases. In this study, we compared molecular methodologies based on duplex real-time quantitative PCR (qPCR) and digital PCR (dPCR) in order to develop effective host resource management strategies. We first evaluated detection capabilities and the impact of potential inhibitors using both methodologies across varying DNA concentrations. Subsequently, we applied these methods to two contrasting French environments: Noirmoutier, characterized by low prevalence and infection intensity, and Arcachon Bay, which exhibits high prevalence and infection intensity. Our results demonstrate that dPCR should be prioritized for detecting and quantifying parasites at low infection intensities (101 -102 cp.µL-1), as it might minimize false-negative results compared to qPCR. Notably, dPCR provided new insights and revealed cryptic infections, demonstrating greater efficiency in detecting P. chesapeaki in lightly infected sites such as Noirmoutier. Conversely, infection intensity was underestimated with dPCR relative to qPCR for clams with moderate to high Perkinsus infection levels (103 cp.µL-1 or higher), proving the latter more suitable for medium to heavily infected areas like Arcachon Bay. These findings are important as they represent the first in situ monitoring of both Perkinsus species using culture-free methodologies. This work provides essential tools for resource management and conservation strategies to address emerging diseases.
(Journal of Invertebrate Pathology. vol. 213, n° 0022-2011, pp. 108417, 03/09/2026)
SBR, SU, CNRS, AD2M, SU, CNRS, SBR, SU, CNRS, ASIM, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Characterization of Organic Matter in Estuarine Wetlands: Mapping Biogeochemical Functions Using Remote Sensing Data
A study was conducted to examine the biogeochemical functions of wetlands in the Seine estuary (northwestern France). The research integrated remote sensing data with field data, including vegetation surveys and biogeochemical measurements. These measurements encompassed elemental analyses (organic carbon and nitrogen) and isotopic analyses (d¹³C and d¹5N) of soil and sediment organic matter. Furthermore, the analysis of dissolved organic matter in porewater was conducted using UV-Visible absorption and EEM fluorescence spectroscopy, while the measurement of enzymatic activities was performed using NAG and BG. An extensive multisource remote sensing work has been carried out across the entire study site to characterize variables measured from space, such as the different vegetation types, the periods of flooding, vegetation production, and humidity. A cross-referencing between these variables and field observations was conducted to assess the potential of remote sensing to retrieve the main ecosystem functions characteristics. This one-year biogeochemical monitoring study of contrasting wetlands in the Seine estuary, differing in vegetation, moisture, connectivity to the watercourse, and use, revealed spatial variations in organic matter characteristics, but very few seasonal variations. For the first time, a correlation matrix was established between biogeochemical field data and function indicators derived from satellite observations.
(pp. 1-2, 03/09/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ECOBIO, UR, INEE-CNRS, CNRS, CNRS, METIS, EPHE, PSL, INSU - CNRS, SU, CNRS, UMR TETIS, Cirad, CNRS, INRAE, LETG - Rennes, UBO EPE, UR2, LETG, UBO EPE, UR2, CNRS, Nantes Univ - IGARUN
Valve behavior of the oysters Crassostrea gigas and Ostrea edulis and physicochemical data measured during a one-year semi-controlled experiment testing the in situ impact of artificial light at night
Artificial light at night (ALAN) is a worldwide anthropogenic pressure altering the natural sun- and moonlight cycles, with putative impacts on organisms' biological rhythms, physiology, and fitness. Compared to terrestrial organisms, ALAN effects have been little studied in coastal ecosystems, despite their widespread exposure to ALAN. To help fill this gap, as part of the LUCIOLE project, we conducted a one-year in situ semi-controlled study to assess the ALAN impact on Crassostrea gigas and Ostrea edulis, two coastal and sessile oyster species likely exposed to ALAN. The experiment took place in the "île aux oiseaux" (44.7°, -1.18°) in Arcachon Bay (France) from December 2023 to November 2024. The experimental platform consisted of two oyster tables spaced 18 meters apart: one table for the control condition exposed to natural light and one table exposed to a continuous and realistic ALAN intensity (⁓10-6 µE/cm2/s; ⁓0.5 lx) using LED strips (white light). 16 individuals of each oyster's species were disposed on each table and were immersed underwater throughout the experiment. Their valve behavior was continuously measured during one year using the High-Frequency Non-Invasive (HFNI) valvometry. In addition to the oyster behavior, several physicochemical parameters were continuously measured underwater during the experiment: temperature, water depth, conductivity, salinity, turbidity, sound pressure magnitude, and light irradiance. This compilation of datasets gives an overview of all physicochemical parameters and behavioral data collected during this experiment.
(03/09/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Underwater sound data, recorded during a 18-month in situ experiment in Helgoland, Germany
This dataset shows the hourly sound pressure magnitude data measured underwater throughout the 18 months of experiment (11th of May 2023 – 31st of August 2024) in Helgoland (Margate) for different frequencies (10 Hz, 20 Hz, 30 Hz, 40 Hz, 50 Hz, 60 Hz, 70 Hz, 80 Hz, 90 Hz, 100 Hz, 200 Hz, 300Hz, 400 Hz, 500 Hz, 600 Hz, and 700 Hz) recorded by the HFNI valvometer. The mean sound pressure magnitude is also presented. Missing data corresponds to the stop of recording of the valvometer.
(03/09/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, AWI, AWI
A wave-resolving two-dimensional vertical Lagrangian approach to model microplastic transport in nearshore waters based on TrackMPD 3.0
Potentially acting as a source or a sink for plastic pollution to the open ocean, nearshore waters remain a challenging context for predicting the transport and deposition of plastic debris. In this study, we present an advanced modeling approach based on the SWASH wave model and the TrackMPD (v3.0) particle transport model to investigate the transport dynamics of floating and sinking microplastics in wave-dominated environments. This approach introduces novel features such as coupling with advanced turbulence models, simulating resuspension and bedload processes, implementing advanced settling and rising velocity formulations, and enabling parallel computation. The wave laboratory experiments conducted by Forsberg et al. (2020) were simulated to validate the model's ability to reproduce the transport of diverse microplastics (varying in density, shape, and size) along a comprehensive beach profile, capturing the whole water column. Our results underscore the robustness of the proposed model, showing good agreement with experimental data. High-density microplastics moved onshore near the bed, accumulating in proximity to the wave-breaking zone, while the distribution of low-density particles varied along the coastal profile depending on the particle properties. The study also sheds light on the primary mechanisms driving microplastic transport, such as Stokes drift, wave asymmetry, and settling/rising velocities. Sensitivity analyses on calibration parameters further confirm the robustness of the model results and the influence of these factors on transport patterns. This research establishes the SWASH–TrackMPD approach as a valuable tool, opening avenues for future studies to contextualize laboratory findings within the complexities of real-world nearshore environments and further refine our comprehension of microplastic dynamics across different beaches and wave-climate conditions.
(Geoscientific Model Development. vol. 18, n° 1991-9603, pp. 319-336, 03/09/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, SIAME, UPPA, MIO, IRD, AMU, INSU - CNRS, UTLN, CNRS