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, 21/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BPH, UB, INSERM
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, 21/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, URI
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, 21/06/2026)
ANSES, UBO EPE, VIMEP, ANSES, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
The Southern Ocean Radiolarian (SO-RAD) dataset: a new compilation of modern radiolarian census data
Abstract. Radiolarians (holoplanktonic protozoa) preserved in marine sediments are commonly used as palaeoclimate proxies for reconstructing past Southern Ocean environments. Generating reconstructions of past climate based on microfossil abundances, such as radiolarians, requires a spatially and environmentally comprehensive reference dataset of modern census counts. The Southern Ocean Radiolarian (SO-RAD) dataset includes census counts for 238 radiolarian taxa from 228 surface sediment samples located in the Atlantic, Indian, and southwest Pacific sectors of the Southern Ocean. This compilation is the largest radiolarian census dataset derived from surface sediment samples in the Southern Ocean. The SO-RAD dataset may be used as a reference dataset for palaeoceanographic reconstructions, or for studying modern radiolarian biogeography and species diversity. As well as describing the data collection and collation, we include recommendations and guidelines for cleaning and subsetting the data for users unfamiliar with the procedures typically used by the radiolarian community. The SO-RAD dataset is available to download from https://doi.org/10.1594/PANGAEA.929903 (Lawler et al., 2021).
(Earth System Science Data. vol. 13, n° 1866-3508, pp. 5441-5453, 21/06/2026)
RSES, ANU, HU, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
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, 21/06/2026)
UNSW, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Hydrodynamics of a hyper-tidal estuary influenced by the world's second largest tidal power station (Rance estuary, France)
The Rance estuary is a relatively small low-discharge steep-sided ria, located along the Brittany coast in northern France, with a maximum spring tidal range of 13.5 m. Taking advantage of this hyper-tidal regime, the first and currently the second largest operational tidal power station in the world was built at the estuary's mouth and has been in operation since the 1960s. Despite the well-known effect of damping of estuarine water levels, little attention has been given to quantifying the influence of the plant on the propagation and asymmetry of the tidal wave inside the estuary. In this study, hydrodynamics and tidal wave patterns were analyzed in this anthropogenically influenced estuarine system. A two-dimensional depth-averaged numerical model of the Rance estuary was developed. Two scenarios without the tidal power plant involving the dam's pre- and post-construction bathymetry (1957 and 2018 respectively) and present-day conditions scenarios were designed, to highlight the impact of bed evolution and the tidal power station on hydrodynamics and tidal asymmetry. Numerical results showed that, without the structure, bathymetric evolution did not substantially influence estuarine hydrodynamics. Nevertheless, on the estuary-side of the dam, the presence of the tidal power plant induced (i) a decrease in both tidal range and tidal prism, (ii) an increase of low water levels, and (iii) a decrease in both flood and ebb currents. Contrastingly, the region close to the structure reacted differently to plant operating modes, with an increase in flood currents (ebb currents) upstream of the sluice gates (downstream of the turbines). For both the natural condition and the artificially-induced hydrodynamic forcing due to the presence of the plant, numerical results showed that the Rance estuary mainly exhibits flood-dominant behavior, with a longer duration of falling than rising water and stronger peak flood currents than ebb currents. Spanning a period of approximately 60 years, this study presents a quantitative analysis of the influence of the tidal power station on the hydrodynamics in the Rance estuary, and its possible consequences for sediment dynamics. This approach is novel for this particular enclosed water body, characterized by the presence of a dam at its mouth and a lock at its uppermost limit.
(Estuarine, Coastal and Shelf Science. vol. 250, n° 0272-7714, 21/06/2026)
EDF [E.D.F.], EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Last millennium climate variability of the varved Lake Jeinimeni geochemical record from NE Chilean Patagonia
Paleoclimate studies in Patagonia show a high Holocene climate variability, strongly controlled by the intensity and latitudinal position of the Southern Westerly Winds. In this study, environmental and climate variability, and in particular winter precipitation, was reconstructed over the last centuries through sedimentological and geochemical analyses of a core from Lake Jeinimeni in North East Patagonia. Visual description, X-ray radiographies and thin section observations point to finely laminated sediments, made by fine sands and light brown clayey silts forming an annual deposition (varves) occasionally interrupted by two Hudson volcano-related tephras and 15 pluri-millimetre to pluri-centimetre coarser sandy to gravely layers. Varve counting confirmed by 210Pb and 137Cs indicates a detrital sequence of at least 750 yr. Based on a correlation with local meteorological data for the 1930–1988AD interval, varve thickness and statistical treatment of XRF geochemical data give information on transport pathway and sedimentary deposit conditions. The sandy laminae correspond to the deposition of high sedimentary load delivered by austral spring snowmelt whereas the clayey silt laminae result of particle settling in the water column during low hydrodynamical conditions. Thicker varves observed in dry conditions underline the importance of aeolian transport in sedimentary deposition. During locally dry and windy summer, the wind may erode and remobilise the sedimentary deposits along the lake margins. The sandy and gravely layers record massive erosional events due to proximal watershed perturbation driven by climatic or tectonic mechanisms. The clastic varves of Lake Jeinimeni document environmental decadal to multidecadal variability in East Patagonia over the last centuries. The more pronounced sediment transition around 1750 CE is consistent with the inception of the Little Ice Age-type event, in agreement with North Patagonian paleoclimate reconstructions derived from glacier advances, lacustrine varve thickness and tree-ring records.
(Quaternary Science Reviews. vol. 269, n° 0277-3791, pp. 107134, 21/06/2026)
AGEs, ULiège, UdeC, UG, KU Leuven, ULiège, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
High-resolution temperature and precipitation variability of southwest Anatolia since 1730 CE from Lake Gölcük sedimentary records
We report high-resolution multiproxy analyses [lithology, μXRF and magnetic susceptibility (MS)] of two short gravity sediment cores from the crater Lake Gölcük, southwest Turkey. Our results provide a detailed hydroclimatic record for the last ~290 years. Aided with factor analysis of μXRF data and 210Pb and 137Cs dating, our multiproxy data show that the Lake Gölcük records documented a series of wet and dry periods between ~ 1730 (±71) and ~ 2018 (±3) CE. Wet periods are evidenced by dark olive green mixed lithology (sandy, clay, and silts) and high values in MS and log(Sr/Ca). On the other hand, dry periods are associated with light olive green clayey mud lithology and high values in log(Ca/K). We relate the wet periods to negative North Atlantic Oscillation (NAO–) and the dry periods to NAO+. Additionally, all wet periods are related with time of low solar activity and dry periods, except Dalton Minimum, are related with periods of high solar activity. Consequently, we suggest that hydroclimatic changes observed in the Lake Gölcük sedimentary records were caused by the influence of largescale atmospheric circulation and solar activity.
(Turkish Journal of Earth Sciences. vol. 45, n° 1300-0985, 21/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Carbon accumulation rates of Holocene peatlands in central–eastern Europe document the driving role of human impact over the past 4000 years
Abstract. Peatlands are one of the largest terrestrial carbon sinks on the planet, yet little is known about the carbon accumulation rates (CARs) of mountainous peatlands. The long-term variability in the size of the associated carbon sink and its drivers remain largely unconstrained, especially when the long-term anthropogenic impact is also considered. Here, we present a composite CAR record of nine peatlands from central–eastern Europe (Romania and Serbia) detailing variability in the rates of carbon accumulation during the Holocene. We show examples of extremely high long-term rates of carbon accumulation (LORCA>120 gCm-2yr-1), indicating that mountain peatlands constitute an efficient regional carbon sink at times. By comparing our data to modelled palaeoclimatic indices and to measures of anthropogenic impact we disentangle the drivers of peat carbon accumulation in the area. Variability in early- and mid-Holocene CARs is linked to hydroclimatic controls, with high CARs occurring during the early Holocene and lower CARs associated with the transition to cooler and moister mid-Holocene conditions. By contrast, after 4000 years (calibrated) before present (years BP), the trends in CARs indicate a divergence from hydroclimate proxies, suggesting that other processes became the dominant drivers of peat CARs. We propose that enhanced erosion following tree cover reduction as well as increased rates of long-distance atmospheric dust fallout might have played a role, as both processes would result in enhanced mineral and nutrient supply to bog surfaces, stimulating peatland productivity. Surprisingly though, for the last 1000 years, reconstructed temperature is significantly correlated with CARs, with rising temperatures linked to higher CARs. Under future climate conditions, which are predicted to be warmer in the region, we predict that peat growth may expand but that this is entirely dependent upon the scale of human impact directly affecting the sensitive hydrological budget of these peatlands.
(Climate of the Past. vol. 17, n° 1814-9324, pp. 2633 - 2652, 21/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR ISEM, Cirad, IRD, EPHE, PSL, UM, CNRS, UBB
A Global Ocean Oxygen Database and Atlas for assessing and predicting deoxygenation and ocean health in the open and coastal ocean
In this paper, we outline the need for a coordinated international effort toward the building of an open-access Global Ocean Oxygen Database and ATlas (GO$_2$DAT) complying with the FAIR principles (Findable, Accessible, Interoperable, and Reusable). GO$_2$DAT will combine data from the coastal and open ocean, as measured by the chemical Winkler titration method or by sensors (e.g., optodes, electrodes) from Eulerian and Lagrangian platforms (e.g., ships, moorings, profiling floats, gliders, ships of opportunities, marine mammals, cabled observatories). GO$_2$DAT will further adopt a community-agreed, fully documented metadata format and a consistent quality control (QC) procedure and quality flagging (QF) system. GO$_2$DAT will serve to support the development of advanced data analysis and biogeochemical models for improving our mapping, understanding and forecasting capabilities for ocean O$_2$ changes and deoxygenation trends. It will offer the opportunity to develop quality-controlled data synthesis products with unprecedented spatial (vertical and horizontal) and temporal (sub-seasonal to multi-decadal) resolution. These products will support model assessment, improvement and evaluation as well as the development of climate and ocean health indicators. They will further support the decision-making processes associated with the emerging blue economy, the conservation of marine resources and their associated ecosystem services and the development of management tools required by a diverse community of users (e.g., environmental agencies, aquaculture, and fishing sectors). A better knowledge base of the spatial and temporal variations of marine O$_2$ will improve our understanding of the ocean O$_2$ budget, and allow better quantification of the Earth’s carbon and heat budgets. With the ever-increasing need to protect and sustainably manage ocean services, GO$_2$DAT will allow scientists to fully harness the increasing volumes of O$_2$ data already delivered by the expanding global ocean observing system and enable smooth incorporation of much higher quantities of data from autonomous platforms in the open ocean and coastal areas into comprehensive data products in the years to come. This paper aims at engaging the community (e.g., scientists, data managers, policy makers, service users) toward the development of GO$_2$DAT within the framework of the UN Global Ocean Oxygen Decade (GOOD) program recently endorsed by IOC-UNESCO. A roadmap toward GO$_2$DAT is proposed highlighting the efforts needed (e.g., in terms of human resources).
(Frontiers in Marine Science. vol. 8, n° 2296-7745, pp. 724913, 21/06/2026)
ULiège, CNES, NOAA, SERC, UNESCO, GEOMAR, IO-PAN, PAN, GHER, ULiège, IOW, IRSI, IFREMER, MBARI, LOV, INSU - CNRS, SU, CNRS, IMEV, INSU - CNRS, SU, CNRS, UBC EOAS, UBC, NIWA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IRD, CECI, CERFACS, INSU - CNRS, CNRS, UCA, OGS, DMI, IGP, JAMSTEC, MRI, JMA, UP System, RSMAS, NORCE, SIO - UC San Diego, UC San Diego, UC, SUNY, CSIR, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, BCCR, BIO / UiB, UiB, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, OVSQ, UVSQ, INSU - CNRS, CNRS, LSU, UMCES, ARC, USF, UBC, LOPS, IRD, IFREMER, INSU - CNRS, UBO EPE, CNRS, HKU