Caractérisation de l’hydrodynamisme des plages et des petits fonds du littoral au sud de l’estuaire de la Gironde à partir de mesures in situ
Le littoral Nord-Médoc, situé au sud de l'estuaire de la Gironde, est soumis à des conditions hydrodynamiques complexes, résultant de l'interaction entre des houles énergétiques et des courants tidaux intenses au sein d'un environnement alternant platiers rocheux, bancs de sables et chenaux de marée. La résultante est un gradient hydrodynamique latitudinal influençant fortement l'évolution morphologique de la côte. Une campagne de mesures de deux semaines a été menée en automne 2022 pour caractériser pour le première fois in situ cette dynamique. Les données ont été collectées le long de trois profils cross-shore s'étendant des petits fonds à l'estran. Les résultats issus de courantomètres profileurs (i.e. ADCP, Aquadopp) et de capteurs de pression ont pu montrer la prédominance des courants tidaux sur l'ensemble du site d'étude (i.e. courant longitudinaux), avec une intensification notable du nord vers le sud. Cette tendance se caractérise par une dominance des courants de flot au Nord, tandis que le jusant domine au sud et au centre du domaine d'étude. Les observations sur les vagues et les courants, en plus d'apporter des éléments de compréhension inédits sur les dynamiques hydrosédimentaires, constituent une base de données indispensable à la validation des modèles de circulation et les prévisions d'évolution du trait de côte dans cette région soumise à l'érosion chronique
(pp. 215-223, 23/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BRGM, LIENSs, INSU - CNRS, ULR, CNRS
Surface circulation in Todos Santos Bay, Baja California, Mexico
(CONTINENTAL SHELF RESEARCH, 23/02/2026)
UNAM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS
Late Miocene onset of the modern Antarctic Circumpolar Current
The Antarctic Circumpolar Current plays a pivotal role in global climate through its strong influence on the global overturning circulation, ocean heat and CO 2 uptake. However, when and how the Antarctic Circumpolar Current reached its modern-like characteristics remains disputed. Here we present neodymium isotope and sortable silt records from sediment cores in the Southwest Pacific and South Indian oceans spanning the past 31 million years. Our data indicate that a circumpolar current like that of today did not exist before the late Miocene cooling. These findings suggest that the emergence of a homogeneous and deep-reaching strong Antarctic Circumpolar Current was not linked solely to the opening and deepening of Southern Ocean Gateways triggering continental-scale Antarctic Ice Sheet expansion during the Eocene-Oligocene Transition (∼34 Ma). Instead, we find that besides tectonic pre-conditioning, the expansion of the Antarctic Ice Sheet and sea ice since the middle Miocene Climate Transition (∼14 Ma) played a crucial role. This led to stronger density contrast and intensified Southern Westerly Winds across the Southern Ocean, establishing a vigorous deep-reaching circumpolar flow and an enhanced global overturning circulation, which amplified the late Cenozoic global cooling. The Antarctic Circumpolar Current (ACC), driven by the interplay among Southern Westerly Winds (SWW), buoyancy forcing and bathymetry 1 , is the largest ocean current on Earth. It actively regulates the transport of heat, moisture, carbon and nutrients between the Southern Ocean and the low-latitude regions, thus substantially influencing atmospheric CO 2 and global climate 1. To assess the future response of the ACC to ongoing climate warming and its impacts on Antarctic Ice Sheet dynamics, global circulation and climate 2 , it is critical to unravel
(Nature Geoscience. vol. 17, n° 1752-0894, pp. 165 - 170, 23/02/2026)
UB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, UTAS, NORCE, BCCR, BIO / UiB, UiB, GET, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS
Sediment discharge from Greenland’s marine-terminating glaciers is linked with surface melt
Abstract Sediment discharged from the Greenland Ice Sheet delivers nutrients to marine ecosystems around Greenland and shapes seafloor habitats. Current estimates of the total sediment flux are constrained by observations from land-terminating glaciers only. Addressing this gap, our study presents a budget derived from observations at 30 marine-margin locations. Analyzing sediment cores from nine glaciated fjords, we assess spatial deposition since 1950. A significant correlation is established between mass accumulation rates, normalized by surface runoff, and distance down-fjord. This enables calculating annual sediment flux at any fjord point based on nearby marine-terminating outlet glacier melt data. Findings reveal a total annual sediment flux of 1.324 + /− 0.79 Gt yr-1 over the period 2010-2020 from all marine-terminating glaciers to the fjords. These estimates are valuable for studies aiming to understand the basal ice sheet conditions and for studies predicting ecosystem changes in Greenland’s fjords and offshore areas as the ice sheet melts and sediment discharge increase.
(Nature Communications. vol. 15, n° 2041-1723, pp. 1332, 23/02/2026)
GEUS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IGN, UCPH, OSU
Bivalve tissues as a recorder of multidecadal global anthropogenic and climate‐mediated change in coastal areas
Recent rapid changes in climate and environmental conditions have significantly impacted coastal ecosystem functioning. However, the complex interplay between global and local effects makes it challenging to pinpoint the primary drivers. In a multi‐ecosystem study, we analyzed pluri‐decadal trends of bivalve‐δ 13 C as recorder of global environmental changes. These trends were correlated with large‐scale natural and anthropogenic climate proxies to identify whether coastal biota responded to global effects. Our findings revealed decreasing bivalve‐δ 13 C trends in all sea regions, mainly linked with increased temperature and atmospheric‐CO 2 concentrations, the later generating a decrease in atmospheric‐CO 2 δ 13 C values (Suess effect) because of fossil‐fuel burning. After removing the Suess effect from bivalve‐δ 13 C trends, ongoing global climate variability continues to affect most ecosystems, possibly intensified by combined, interacting regional or local effects. These results highlight the need to consider large‐scale effects to fully understand ecosystem and food web responses to the multiple effects of global change.
(Limnology and Oceanography Letters, 23/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, FTMC, BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA, CCEM, IFREMER, DYNECO, IFREMER
Characterization of Multi-Decadal Beach Changes in Cartagena Bay (Valparaíso, Chile) from Satellite Imagery
Sandy coastlines are very dynamic spaces affected by a variety of natural and human factors. In Central Chile, changes in oceanographic and wave conditions, modes of inter-annual climate variability such as El Niño Southern Oscillation (ENSO), and extreme events such as earthquakes and tsunamis condition the beach morphology. At the same time, direct human actions alter the arrival of sediments to the coast and their alongshore distribution. Despite the relevance of the beaches for this coastal region and the interesting relationship their morphology has with the aforementioned factors, there is a lack of robust morphological datasets to provide a deep characterization and understanding of the dynamism of the Chilean coast. Based on the information provided by satellite-derived shorelines (SDSs) defined by using the SHOREX algorithm, this paper characterizes the morphological changes of Playa Grande in Cartagena Bay (Central Chile) during the period 1985–2019. The shoreline position data are analyzed in the context of changing beach transforming elements, allowing for a better understanding of the changes according to multiple drivers. While some of these factors, such as earthquakes or coastal storms, have a punctual character, changes in wave patterns vary at different time scales, from seasonal to multi-annual, linked to climate phases such as ENSO. Its effects are translated into shoreline erosion and accretion conditioned by the morphology and orientation of the coast while influenced by the availability of sediment in the coastal system. According to that, a conceptual model of the dynamism and redistribution of sediment in the Bay of Cartagena is proposed. The work proves the high utility that the systematic analysis of multi-decadal SDS datasets obtained from the images acquired in the optical by the Landsat and Sentinel-2 offer for beach monitoring and understanding the coastal dynamism.
(Remote Sensing. vol. 16, n° 2072-4292, pp. 2360, 23/02/2026)
UPV, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, PUC
A new species of Loimia (Annelida, Terebellidae) from Papua New Guinea, with comments on other species recorded in the region
We describe a new species of Loimia, from shallow waters off Northern Papua New Guinea and compare morphologically to other species recorded from the region and a key is provided. We provide a Maximum likelihood tree for species of Loimia for which we have data and it forms a distinct clade from other species. Finally, we discuss characters that we consider as useful specific characters in this large genus, which includes many poorly described species.
(Ocean and Coastal Research. vol. 72, n° 2675-2824, pp. e24003, 23/02/2026)
UMS POREA, INSU - CNRS, CNRS, INRAE, SIO - UC San Diego, UC San Diego, UC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Toxicity evaluation of water-accommodated fraction of heavy and light oils on the rainbow trout fish cell line RTL-W1.
Fish are currently used models for the toxicity assessment of chemicals, including polycyclic aromatic hydrocarbons (PAHs). Alternative methods including fish cell lines are currently used to provide fast and reliable results on the toxic properties of chemicals while respecting ethical concerns about animal testing. The Rainbow trout liver cell line RTLW1 was used to analyze the effects of two water-accommodated fractions from two crude oils: Arabian Light crude oil (LO) and refined oil from Erika (HO). Several toxicity endpoints were assessed in this study, including cytotoxicity, EROD activity, DNA damage (comet and micronucleus assays), and ROS production. RTL-W1 cells were exposed for 24 h at two or three dilutions of WAF at 1000 µg/L (0.1% (1 μg/L), 1% (10 μg/L), and 10% (100 μg/L)) for cytotoxicity and EROD activity and 1% and 10% for ROS production and genotoxicity). Exposure of RTL-W1 cells to LO WAF induced a significant increase of EROD activity and ROS production and altered DNA integrity as revealed by both the comet assay and the micronucleus test for 10 µg/L of LO. On the other hand, HO WAF exhibited limited toxic effects except for an EROD induction for 1% WAF dilution. These results confirmed the usefulness of RTL-W1 cells for in vitro toxicological assessment of chemical mixtures.
(Environmental Science and Pollution Research. vol. 31, n° 0944-1344, pp. 49715-49726, 23/02/2026)
VIMEP, ANSES, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, Cedre
Toxicity of environmental and polystyrene plastic particles on the bivalve Corbicula fluminea: focus on the molecular responses
Among aquatic organisms, filter feeders are particularly exposed to the ingestion of microplastics (MPs) and nanoplastics (NPs). The present study investigates the effect of environmental microplastics (ENV MPs) and nanoplastics (ENV NPs) generated from macro-sized plastic debris collected in the Garonne River (France), and polystyrene NPs (PS NPs) on the freshwater bivalve Corbicula fluminea. Organisms were exposed to plastic particles at three concentrations: 0.008, 10, and 100 μg L−1 for 21 days. Gene expression measurements were conducted in gills and visceral mass at 7 and 21 days to assess the effects of plastic particles on different functions. Our results revealed: (i) an up-regulation of genes, mainly involved in endocytosis, oxidative stress, immunity, apoptosis, and neurotoxicity, at 7 days of exposure for almost all environmental plastic particles and at 21 days of exposure for PS NPs in the gills, (ii) PS NPs at the three concentrations tested and ENV MPs at 0.008 μg L−1 induced strong down-regulation of genes involved in detoxication, oxidative stress, immunity, apoptosis, and neurotoxicity at 7 days of exposure in the visceral mass whereas ENV MPs at 10 and 100 μg L−1 and all ENV NPs induced less pronounced effects, (iii) overall, PS NPs and ENV MPs 0.008 μg L−1 did not trigger the same effects as ENV MPs 10 and 100 μg L−1 and all ENV NPs, either in the gills or the visceral mass at 7 and 21 days of exposure. This study highlighted the need to use MPs and NPs sampled in the environment for future studies as their properties induce different effects at the molecular level to living organisms.
(Ecotoxicology. vol. 33, n° 0963-9292, pp. 709-721, 23/02/2026)
BIOSSE, UCO, UCO, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ULaval, GR, UR, INSU - CNRS, CNRS, IPGP - UMR_7154, INSU - CNRS, IGN, UR, IPG Paris, CNRS, UPCité
Imazalil and prochloraz toxicokinetics in fish probed by a physiologically based kinetic (PBK) model
Azole fungicides are highly suspected endocrine disruptors (EDs) and are frequently detected in surface water. Among them, there are prochloraz (PCZ), a commonly used molecule for ED studies, and imazalil (IMZ), a highly suspected ED. Little is known about their toxicokinetic (TK) behavior in fish. Hence, research suggested that an improved risk assessment could be achieved by gaining insight into their TK behavior. The aim of this study is to understand and model the TK of both substances in different fish species, irrespective of the scheme of exposure. TK data from the literature were retrieved including different modes of exposure (per os and waterborne). In addition, two experiments on zebrafish exposed to either IMZ or PCZ were performed to address the lack of in vivo TK data. A physiologically based kinetic (PBK) model applied to IMZ and PCZ was developed, capable of modeling different exposure scenarios. The parameters of the PBK model were simultaneously calibrated on datasets reporting internal concentration in several organs in three fish species (original and literature datasets) by Bayesian methods (Monte Carlo Markov Chain). Model predictions were then compared to other experimental data (i.e., excluded from the calibration step) to assess the predictive performance of the model. The results strongly suggest that PCZ and IMZ are actively transported across the gills, resulting in a small fraction being effectively absorbed by the fish. The model’s results also confirm that both molecules are extensively metabolized by the liver into mainly glucuronate conjugates. Overall, the model performances were satisfying, predicting internal concentrations in several key organs. On average, 90% of experimental data were predicted within a two-fold range. The PBK model allows the understanding of IMZ and PCZ kinetics profiles by accurately predicting internal concentrations in three different fish species regardless of the exposure scenario. This enables a proper understanding of the mechanism of action of EDs at the molecular initiating event (MIE) by predicting bioaccumulation in target organs, thus linking this MIE to a possible adverse outcome.
(Environmental Science and Pollution Research. vol. 31, n° 0944-1344, pp. 52758-52773, 23/02/2026)
INERIS, SEBIO, INERIS, URCA, ULH, NU, URCA, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS