How does habitat use influence PFAS contamination in wildlife? Combining stable isotopes and GPS tracking in three gull species
Per-and polyfluoroalkyl substances (PFAS) are toxic and persistent compounds widely distributed in the environment and accumulate in top predators, including seabirds. Because of the biomagnification potentials of some PFAS, diet is thought to be a key exposure route for PFAS. However, other factors, such as habitat use, may mask interspecific differences in PFAS exposure expected from trophic structure. Among seabirds, gulls are generalist that forage in both terrestrial and marine habitats, making them relevant models to concurrently investigate the influence of foraging habitats and trophic position on PFAS exposure. We combined plasma PFAS concentrations with GPS tracking and stable isotopes to define foraging habitats (δ 13 C; δ 34 S; GPS) and trophic positions (δ 15 N) in three sympatric gull species breeding in France (Isle of Ré). In herring gulls (Larus argentatus), long-chain perfluoroalkyl carboxylic (PFCAs) were positively correlated with high trophic resources from marine habitats. We found compound-and sex-dependent relationships between PFAS concentrations and stable isotope values in lesser black-backed gulls (Larus fuscus), while no association was found with habitat use. No association was found between PFAS levels and stable isotopes in great blackbacked gulls (Larus marinus). Our study suggests that coastal habitat could be a source of PFCA contamination and highlights that the influence of habitat use on gull exposure to PFAS varied depending on species, sex, and compounds.
(Environmental Pollution, n° 0269-7491, 01/12/2025)
SU, CEBC, ULR, CNRS, INRAE, LIENSs, INSU - CNRS, ULR, CNRS, LPO, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ULR
Endocrine effects of Imazalil on aromatase expression, vitellogenesis and ovarian histology using cyp19a1a-eGFP-casper transgenic zebrafish
Considering the hazards and risks posed by endocrine disrupting chemicals (EDC) to organisms, there is a need to study their effects. To that end, transgenic fish are powerful models that can provide mechanistic information regarding the endocrine activity of test chemicals. In this study, we used a newly developed transgenic zebrafish line (cyp19a1a-eGFP-casper) in the OECD 21-day fish assay (OECD TG 230) to provide additional mechanistic insight on Imazalil (IMZ; 1.9; 9.9 and 140.7 μg/L). After 21 days of exposure to IMZ, the circulating concentrations of 17-β-estradiol (E2) and vitellogenin decreased in females, reflecting the aromatase activities inhibition. Exposure to 140.7 μg/L of IMZ for 21 days also resulted in a change in the proportion of the different oocyte stages in the ovaries, with an accumulation of large oocytes in exposed females. In addition to the classical endpoints, in vivo GFP fluorescence was quantified in the ovaries during the time course of the exposure to follow gonadal aromatase expression. After seven days of exposure, ovarian aromatase expression increased in females exposed to medium and high concentrations of IMZ, persisting over the 21-day of exposure in fish from the highest concentration group and reflecting a compensatory response to the aromatase enzymatic activities inhibition. Results from the present study provided valuable information on the mode of action and the effects of IMZ in zebrafish. Transgenic zebrafish exposure to IMZ caused a cascade of responses consistent with effects reported for wild-type fish exposed to azole fungicides, both qualitatively and quantitatively. The cyp19a1a-eGFP (-casper) transgenic zebrafish lines, allowed in vivo monitoring of gonadal aromatase expression in a time- and concentration-dependent manner thereby demonstrating their relevance to provide complementary mechanistic information on aromatase in regulatory assays such as OECD TG 230.
(Aquatic Toxicology. vol. 289, n° 0166-445X, pp. 107580, 01/12/2025)
INERIS, SEBIO, INERIS, URCA, ULH, NU, URCA, CNRS, LPGP, Biosit : Biologie - Santé - Innovation Technologique, INRAE, LPTC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR MARBEC, IRD, IFREMER, CNRS, UM
Toward a typology of river functioning: a comprehensive study of the particulate organic matter composition at the multi-river scale
In river systems, particulate organic matter (POM) originates from various sources with distinct dynamics related to production, decomposition, transport, and burial, leading to spatiotemporal heterogeneity in the POM pool. This study uses C and N isotope and element ratios, Bayesian models and multivariate analyses to (1) quantify relationships between POM composition and environmental forcings, and (2) propose a typology of river functioning based on POM composition and their seasonal dynamics. Twenty-three temperate rivers, representing a large diversity of temperate conditions, were sampled fortnightly to monthly over one to seven years at their River-Estuary Interface (REI). Phytoplankton and labile terrestrial material were found in all rivers, while sewage and refractory terrestrial material appeared in a few. Across all rivers, phytoplankton dominance correlated with agricultural surfaces, labile terrestrial material with organic-rich leached soil, and refractory terrestrial matter with steep, soil-poor catchments. Seasonal dynamics mainly depended to phytoplankton growth, river discharge, and sediment resuspension. Statistical regionalisation identified four river-dynamics types: (1) POM is dominated by labile terrestrial material year-round; (2) POM is composed of labile and refractory terrestrial material plus phytoplankton with variable seasonality; (3) POM is composed of phytoplankton and labile terrestrial material without pronounced seasonality; and (4) POM is composed of phytoplankton and labile terrestrial material with pronounced seasonality. This research offers a comprehensive understanding of POM composition, dynamics, and drivers at the REI in temperate climates, complementing similar study in coastal systems. Future similar research on estuaries is called to refine knowledge along the Land-Ocean Aquatic Continuum.
(Biogeosciences. vol. 22, n° 1726-4170, pp. 7363-7401, 27/11/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LERPC, COAST, IFREMER, IPREM, UPPA, INC-CNRS, CNRS, CRESCO, MNHN, IFREMER, CEFREM, UPVD, INSU - CNRS, CNRS
ClimLoco1.0: CLimate variable confidence Interval of Multivariate Linear Observational COnstraint
Projections of future climate are key to society's adaptation and mitigation plans in response to climate change. Numerical climate models provide projections, but the large dispersion between them makes future climate very uncertain. To refine them, approaches called observational constraints (OCs) have been developed. They constrain an ensemble of climate projections using some real-world observations. However, there are many difficulties in dealing with the large literature on OC: the methods are diverse, the mathematical formulation and underlying assumptions are not always clear, and the methods are often limited to the use of the observations of only one variable. To address these challenges, this article proposes a new statistical model called ClimLoco1.0, which stands for “CLimate variable confidence Interval of Multivariate Linear Observational COnstraint”. It describes, in a rigorous way, the confidence interval of a projected variable (its best guess associated with an uncertainty at a confidence level) obtained using a multivariate linear OC. The article is built up in increasing complexity by expressing three different cases – the last one being ClimLoco1.0, the confidence interval of a projected variable: unconstrained, constrained by multiple real-world observations assumed to be noiseless, and constrained by multiple real-world observations assumed to be noisy. ClimLoco1.0 thus accounts for observational noise (instrumental error and climate-internal variability), which is sometimes neglected in the literature but is important as it reduces the impact of the OC. Furthermore, ClimLoco1.0 accounts for uncertainty rigorously by taking into account the quality of the estimators, which depends, for example, on the number of climate models considered. In addition to providing an interpretation of the mathematical results, this article proposes graphical interpretations based on synthetic data. ClimLoco1.0 is compared to some methods from the literature at the end of the article and is used in a real case study in the appendix.
(Geoscientific Model Development. vol. 18, n° 1991-9603, pp. 9015-9038, 25/11/2025)
ASTRAL, IMB, UB, Bordeaux INP, CNRS, Inria, UB, Bordeaux INP, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Response of phytoplankton communities to the onset of the 2020 summer marine heatwave in the Drake Passage and Antarctic Peninsula
Abstract. Extreme warming events are increasingly more intense and frequent in the global ocean. These events are predicted to drive profound and widespread effects on marine ecosystems, yet their impact on phytoplankton, the base of the marine food web, is still largely unknown. Our understanding of the impact of these phenomena in marine ecosystems is particularly poor in the remote and logistically challenging Southern Ocean. During summer 2020, the research vessel Hespérides sampled the water column of the Drake Passage and northern Antarctic Peninsula before (early January) and during the early phase (late January-early February) of a Marine Heat Wave (MHW), that resulted in sea surface temperature anomalies of up to +3 °C. Here, we take advantage of this exceptional opportunity to document the effects of an extreme warming event on the nutrient and phytoplankton (diatom and coccolithophores) distributions across the main zonal systems of the Southern Ocean. Overall, our results indicate that biogeographical variability of diatom and coccolithophore assemblages, the two dominant phytoplankton groups in the Southern Ocean, mirrored the physical and chemical properties of the water masses delineated by the Southern Ocean fronts before and during the onset of the marine heat wave. Analysis of a suite of satellite-derived oceanographic parameters revealed that development and persistence of the 2020 marine heat wave were closely tied to mesoscale anticyclonic eddy dynamics. The increase in sea surface temperatures during the onset of the marine heat wave was associated with a remarkable increase in diatom abundance reaching bloom concentrations and a shift in the diatom assemblage towards an increase in the relative abundance of the small diatom Fragilariopsis cylindrus/nana in the southern Drake Passage. Notably, the diatom bloom was not coupled with a statistically significant change in chlorophyll a, as derived from in-situ fluorescence, or modelled Net Primary Production. It is likely that the differing contribution of other phytoplankton groups and/or a shift in the average phytoplankton size before and during the MHW might be responsible for these results. Average coccolithophore abundance was lower than previous studies in the Drake Passage and decreased during the MHW. We speculate that the remarkable nitrate decrease by approximately one order of magnitude lower than average summer concentrations might have been responsible for the reduction in coccolithophore numbers. Low nitrate levels are attributed to either the advection of nitrate poor waters from lower latitudes by an anticyclonic eddy and/or nutrient consumption by substantial development of soft-tissue phytoplankton biomass. Overall, our results reinforce the notion that a warmer Southern Ocean will favour an increase of small phytoplankton cells in the southern Drake Passage and northern Antarctic Peninsula with unpredictable consequences in the marine-food web and biogeochemical cycles that need to be urgently quantified and parametrized.
(Biogeosciences. vol. 22, n° 1726-4170, pp. 7205 - 7232, 25/11/2025)
ICMAN, CSIC, EPHE, PSL, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UB, IACT, CSIC, UGR, IGME, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GEOTRAC, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, JAMSTEC
What environmental and human factors influence the decision of a beachgoer to enter the water at a high-energy beach? Application to South Western France
Background Coastal areas are among the most attractive destinations worldwide, but engaging in water-based recreational activities is not without risk. The overall bathing risk ultimately results from the combination of natural physical hazards (e.g. rip currents, shore break waves) and the individuals who expose themselves to them. Among the growing body of beach safety studies, many have identified the lack of exposure data as a severe limitation (1). A first attempt to address this was made by considering the beachgoer population rather than the total population to assess incident rates (2). We believe our research takes a step further by estimating the proportion of beachgoers who enter the water on a given day. Methods We built a unique multidisciplinary database combining data collected by an on-site beachgoers survey, weather stations, marine buoys and tidal reconstruction. We employed a logistic regression analysis to predict beachgoer’s decision to enter the water on any given day at a high-energy recreational beach. Results We demonstrated that both environmental and human factors influence a beachgoer’s decision to enter the water. Daily mean wave height and daily mean insolation duration were significant predictors at the p<0.001 level, while age, place of residence and self-confidence in swimming out of a rip current were significant at the p<0.05 level or higher. Our model has an accuracy, F-Score, precision and recall of 71%, 73%, 86%, 79% respectively. Conclusion Beachgoer exposure on any given day can ultimately be predicted by coupling our model with beach attendance models (3). This would allow for the design of rescue and preventive operations on days with high expected exposure. While models based solely on environmental factors can be used to forecast beach risks, incorporating human factors into the model provides valuable insight for crafting prevention messages. To this end, forecasting tools must be based on behavioural analytical framework as much as possible
(20/11/2025)
UR ETTIS, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
From Fields to Homes: How Agricultural Pesticides Contaminate Residential Environments? Findings from the PESTIPREV Study, France
Pesticide sprayings on crops can contaminate nearby homes, yet factors driving pesticide penetration indoors remain poorly understood. Our objective was to study the influence of factors related to air exchange and occupants track-in on agricultural pesticide surface loadings (SLs) measured in homes near vineyards. Indoor surface wipes were collected in 31 homes near vineyards during the peak pesticide application season in 2020 and 2021 and analyzed via LC/MS/MS or GC/MS/MS. Questionnaire data provided information on air exchange and track-in factors. Linear mixed models assessed their effects on SLs of seven fungicides across all surfaces (n = 667) and stratified by recently cleaned surfaces (n = 217), floors (n = 105), and high dusty surfaces (n = 130). Daytime airing reduced floor SLs by 14–28%, depending on the pesticide, but increased SLs by up to 38% on high surfaces. Nighttime airing was associated with a 20–65% increase in recently cleaned surface SLs. Double-flow ventilation increased high surface SLs by 21–126%, while ventilation grids reduced contamination, especially on floors (up to 51%). Home insulation tended to raise SLs. Pets and gardening were the main sources of pesticide track-in, contributing to an 11–87% increase in floor SLs. However, pets substantially reduced SLs on high surfaces. Direct yard access increased SLs in rooms by 5–10%. Room occupancy and outdoor activities showed mixed effects depending on the surface, whereas shoe removal and doormat use showed no significant impact. While ventilation effects remain complex to interpret for prevention, track-in findings suggest hygiene measures could help reduce indoor pesticide SLs.
(Water, Air, and Soil Pollution. vol. 237, n° 0049-6979, pp. 150, 19/11/2025)
BPH, UB, INSERM, ARS NA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ECOSYS, INRAE
One-year high-frequency environmental and behavioral data from ALAN experience in a French coastal area
Despite the widespread exposure to artificial light at night (ALAN) on coastal ecosystems, its effects are poorly studied, and data remain scarce compared to terrestrial ecosystems. Coastal areas are critical for ecosystem services, providing biodiversity, social, and commercial benefits. To acquire high-quality data on ALAN impacts on coastal ecosystems, we conducted a one-year in situ study in the “Ile aux Oiseaux” site, part of the Arcachon Bay (France), from December 2023 to November 2024. The experimental platforms consisted of two oyster tables: one for the control condition exposed to natural light and one exposed to a skyglow ALAN intensity using underwater LEDs. The impacts of ALAN were assessed using two oyster species (Crassostrea gigas and Ostrea edulis) as sentinel organisms, recording continuously their valve behavior using high-frequency non-invasive valvometer biosensors. To characterize the local environment, the experimental platform was also equipped with multiple sensors for the long-term measurement of light irradiance and additional physical parameters (temperature, water level, salinity, turbidity, conductivity, and low-frequency sound).
(Scientific Data. vol. 12, n° 2052-4463, pp. 1808, 18/11/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GEODE, UT2J, Comue de Toulouse, CNRS
Shallow benthic invertebrate communities in relation to substrate types in coastal environments of the sub-Antarctic Crozet archipelago.
Coastal ecosystems of sub-Antarctic islands are threatened by increasing climate-driven changes and direct anthropogenic pressures. Significant effects on marine communities are expected, but benthic ecosystems of these isolated islands remain largely under-explored. Effective preservation of these nearshore environments requires deeper ecological assessments and comprehensive biodiversity knowledge. In this regard, this study reports findings from a survey carried out in 2021 at two sites – Baie du Marin and Crique du Sphinx – located on the eastern coast of Ile de la Possession (sub-Antarctic Crozet archipelago, Southern Ocean). We investigated the composition and structure of nearshore benthic faunal communities using a quantitative fieldwork protocol and an integrative molecular- and morphology-based taxonomic approach. A total of 124 morphotypes were identified, including a high proportion (72%) of rare species. Both sites exhibited similar benthic invertebrate communities. Structurally complex habitats such as hard substrates or areas dominated by macroalgae exhibited higher species richness and diversity. The investigated benthic invertebrate communities are typical of the sub-Antarctic area but featured unique structures, including dense tube-dwelling polychaete colonies. This study will provide a baseline for future monitoring programs and for the preservation of sub-Antarctic coastal benthic ecosystems.
(Frontiers in Marine Science. vol. 12, n° 2296-7745, pp. 1692217, 14/11/2025)
BGS, EPHE, PSL, CNRS, UBE, LBM, ULB, LECOB, SU, CNRS, OOB, SU, CNRS, ULiège, ULiège, UMAG, CHIC, BASE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IMR, UiB, UIB, UAM
Développement de nouveaux algorithmes d’apprentissage statistique pour coupler projections climatiques et observations passées en vue de réduire les incertitudes du changement climatique à venir
Le climat change à cause des émissions humaines de gaz à effet de serre. Les modèles climatiques permettent de projeter son évolution selon des scénarios futurs d’émissions humaines (SSP). Cependant, les résultats des différents modèles climatiques développés dans le monde sont quantitativement divergents, générant une grande incertitude appelée par la suite incertitude modèle.Cette incertitude modèle est particulièrement forte pour la circulation méridienne de retournement en Atlantique (AMOC), un système de courants océaniques qui affecte les conditions climatiques de nombreuses régions du globe. En effet, même si tous les modèles climatiques CMIP6 prévoient un ralentissement de l’AMOC, l’ampleur varie fortement : en moyenne, ils projettent un ralentissement AMOC de 33 ± 36% d’ici 2100 (confiance 90%, scénario SSP2-4.5).Pour réduire l’incertitude modèle, les méthodes dites de contraintes observationnelles (COs) ont été récemment développées. Elles contraignent les projections des modèles par l'observation réelle d'une (univarié) ou de plusieurs (multivarié) variables. Ces approches sont cependant difficiles à utiliser car dans la littérature (i) les fondements statistiques sur lesquels elles reposent ne sont pas toujours identiques et manquent souvent de clarté, (ii) les approches sont très diversifiées et souvent univariées, et (iii) le choix des variables observables est subjectif. Cette thèse se compose de trois articles qui traitent chacune de ces trois problématiques.(i) Le premier article propose un modèle statistique rigoureux pour une CO linéaire multivariée, appelé ClimLoco1.0. Il prend en compte l’incertitude sur l'observation réelle et l'incertitude provenant du nombre limité de modèles climatiques, toutes deux souvent négligées ou mal considérées dans la littérature. Dans un souci de pédagogie, l’article détaille progressivement la construction de ClimLoco1.0 et fournit des interprétations graphiques des résultats mathématiques obtenus.(ii) Le second article compare les performances de quatre approches de CO, par validation croisée. L’AMOC future y est contrainte soit par l’AMOC passée (univarié), soit par l’AMOC passée, la température et la salinité de surface de différentes régions océaniques choisies subjectivement (multivarié). L’approche la plus performante est la régression Ridge dans le cas multivarié, qui est particulièrement adaptée à notre étude. Elle fournit une estimation du ralentissement AMOC d’ici 2100 de 51 ± 8% (SSP2-4.5). Ce ralentissement plus important que celui estimé par la moyenne multi-modèle (33%) résulte principalement de la considération du biais des modèles climatiques concernant la salinité de surface en Atlantique sud. Cela est en accord avec la littérature reliant ce biais à la rétroaction positive d’advection de salinité, un mécanisme clé pour la stabilité de l’AMOC.(iii) Le troisième article utilise une méthode spécifique de clustering pour créer des groupes de régions associées à de nombreuses variables climatiques. Ces groupes sont interprétés pour identifier les mécanismes qui expliquent l’incertitude modèle de l’AMOC future. Ils sont également résumés par des variables synthétiques qui sont utilisées dans la méthode ClimLoco1.0 pour contraindre cette incertitude modèle. Cette méthode suggère que l’incertitude modèle est notamment expliquée par la rétroaction positive d’advection de salinité et les remontées d’eaux profondes, en accord avec la littérature. Contrainte par l’observation de ces variables synthétiques, l'estimation du ralentissement AMOC d'ici 2100 est de 45 ± 10% (SSP2-4.5).Les deux derniers articles estiment un ralentissement AMOC similaire, qui est plus important et moins incertain que celui estimé par la simple moyenne multi-modèles. Il semble donc opportun que ce résultat soit pris en compte afin d’améliorer les projections climatiques et les stratégies d'adaptation associées.
(14/11/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS