The Role of DNA Methylation and ZBTB Transcription Factors in Sex Differentiation, Maintenance and Heat‐Induced Masculinization in Zebrafish
Sex differentiation, the process by which an organism develops as a male or female, can be influenced by the environment in many species. High temperature, or pollutant exposure, can lead to skewed sex‐ratios and genotype‐phenotype mismatches that can seriously threaten populations and biodiversity. Understanding the mechanisms involved in sex differentiation is thus of crucial importance. In the present study, we analyzed the DNA methylation and transcriptional changes that occur during sex differentiation in zebrafish. Our results support the fact that DNA methylation is not only involved in sex differentiation but also in sex maintenance. Initiation of sex differentiation was associated with a DNA demethylation event. Subsequently, a second DNA methylation remodeling event, which coincided with the loss of bi‐potentiality, was observed in males. Among the genes under study, the methylation level of the aromatase gene was found to be the most robust sex marker. However, genes encoding for transcription factors of the ZBTB family offered a more precocious marker since sex‐specific changes in their transcription levels preceded changes in DNA methylation. In addition, their transcription levels were found be sensitive to a known masculinizing factor, i.e. temperature. Our results thus support an unexpected role of ZBTB proteins in sex differentiation.
(Molecular Reproduction and Development. vol. 93, n° 1040-452X, 26/05/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
A multi-proxy sediment record of atmospheric contaminant deposition in the Paris Basin since the nineteenth century
Small ponds represent valuable but still underexploited archives for reconstructing long-term environmental contamination, particularly those disconnected to fluvial networks. In this study, a sediment core from the Saint-Denis pond (Paris Basin, France) was used to reconstruct the historical evolution of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and per- and polyfluoroalkyl substances (PFAS) over the last 150 years. The 137Cs record, characterized to the well-defined atmospheric fallout peak in 1963, was retained as the most robust age model, particularly for the second half of 20th century, when investigated contaminant dynamics were strongly influenced by human activities. The resulting chronology indicates continuous sediment accumulation from the late 19th century to 2021.Temporal trends in PAHs, PCBs, and PFAS closely match known historical production, use, and regulatory phases, providing independent validation of the 137Cs-based age model. Although indirect contaminant transfers via surrounding forest soils cannot be entirely excluded, the sediment record predominantly reflects atmospheric-driven contamination. This multi-proxy approach demonstrates the relevance of pond sediments for environmental monitoring and retrospective assessment of long-term contamination trends at the regional scale.
(Environmental Monitoring and Assessment. vol. 198, n° 0167-6369, pp. 625, 21/05/2026)
METIS, EPHE, PSL, INSU - CNRS, SU, CNRS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, iSTeP, INSU - CNRS, SU, CNRS, CY, GéHCO, UT, NEOLAiA, GEDI, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA
Contrasting effects of seasonality and agricultural practices on periphytic biofilm metabolism and functions
Intensive agriculture exerts a strong pressure on biodiversity and the environment. Agroecological farming promoting ecological processes and ecosystem services appears as a promising alternative to conciliate commodity production and low environmental footprint. However, we lack proper quantitative assessment of the impact of various farming practices on adjacent natural ecosystems. Aquatic environments are particularly sensitive to land-use change, making it essential to evaluate how agricultural practices influence their ecological integrity. Periphytic biofilms, complex microbial communities colonizing submerged substrates, are widely recognized as relevant indicators of structural and functional biodiversity in aquatic ecosystems. Their rapid response to environmental variation makes them especially suitable for assessing the effects of agricultural practices. In this study, we investigated periphytic biofilms from two rivers, Barbanne and Engranne, along a gradient of agricultural practices (conventional, intermediate, organic). Biofilms were colonized on artificial substrates for four weeks during two seasons: spring (May–June 2025) and autumn (October–November 2025). Functional traits (algal composition, organic matter, photosynthetic and enzymatic activities), physicochemical parameters, and microbial activity through untargeted metabolomics were analyzed. During spring, functional traits revealed a clear spatial separation between the rivers. Engranne showed higher proportions of cyanobacteria and diatoms, with greater organic matter content, whereas Barbanne was dominated by green algae and exhibited higher copper tolerance. Multivariate analyses revealed a strong seasonal structuring of samples, distinguishing both rivers and seasons, but showing no clear effect of agricultural practices. Metabometabolomic profiles displayed the same trend, with samples grouped by season and not by agricultural practices. Overall, seasonality explained the observed variability better than the agricultural practices. This study underscores the need for multi‑season, multi-scale and long‑term monitoring to reliably evaluate the effects of agricultural practices on aquatic ecosystems.
(19/05/2026)
UR EABX, INRAE, UB, CNRS, INRAE, LPTC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR SAVE, UB, Bordeaux Sciences Agro, INRAE
Metametabolome and developmental response of Rainbow trout holobiont embryos to suspected endocrine disruptors
Many synthetic chemicals used in agriculture and industry, classified as endocrine disruptors (EDs), are ubiquitous in aquatic environments. Fish embryos are particularly vulnerable to such compounds. While apical effects have been described at the morphological level, knowledge regarding their impact on the global metabolism of developing embryos remains limited. In this context, untargeted metabolomics represents a powerful approach, as it enables sensitive characterization of the molecular/biochemical phenotype alongside physiological descriptors. This study aims to characterize the effects of two EDs on the metabolism and physiology of rainbow trout (Oncorhynchus mykiss) embryos, a species of economic and ecological importance. To achieve this, trout larvae were exposed daily for one month to sodium fluoride (1.5 and 5 mg/L), a potential ED used in industrial processes, and tebuconazole (20 and 100 µg/L), a well-established endocrine-disrupting fungicide widely applied in agriculture. Sampling was conducted at 8, 14, 20, 27 days of exposure.The metabolome was analyzed using an untargeted approach based on UPLC-HRMS-TOF. Data were processed with MZmine and analyzed using multivariate chemometric methods, including PCA, sPLS-DA, HCA, ASCA, and AMOPLS. Metabolite annotation was performed using SIRIUS and MSnet. Physiological differences were observed, with embryos exposed to the highest concentrations exhibiting reduced standard length. Metabolomic profiles showed strong clustering driven by sampling time. ASCA and AMOPLS analyses indicated that time accounted for 43% of total variation, whereas ED concentration explained only 2.5%. Overall, this study highlights the relevance of untargeted metabolomics for detecting metabolic disruptions induced by EDs during critical early developmental stages.
(19/05/2026)
UB, CNRS, INRAE, UR EABX, INRAE, LPTC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Global Carbon Budget 2025
Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesise datasets and methodologies to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2 emissions (EFOS) are based on energy and cement production data. Emissions from land-use change (ELUC) are estimated by bookkeeping models based on land-use data. The global atmospheric CO2 growth rate (GATM) is computed from changes in concentration measured at surface stations. The global net uptake of CO2 by the ocean (SOCEAN) is estimated with global ocean biogeochemistry models and observation-based f CO2-products. The global net uptake of CO2 by the land (SLAND) is estimated with dynamic global vegetation models. Additional lines of evidence are provided by atmospheric inversions, atmospheric oxygen measurements, ocean interior observation-based estimates, and Earth System Models. This year, we introduced corrections on the ELUC, SOCEAN and SLAND estimates. The sum of all sources and sinks results in the carbon budget imbalance (BIM), a measure of imperfect data and incomplete understanding of the contemporary carbon cycle. All uncertainties are reported as ± 1σ . For the year 2024, EFOS increased by 1.1 % relative to 2023, with fossil emissions at 10.3 ± 0.5 GtC yr−1 (including the cement carbonation sink, 0.2 GtC yr−1), ELUC was 1.3 ± 0.7 GtC yr−1, for total anthropogenic CO2 emissions of 11.6 ± 0.9 GtC yr−1 (42.4 ± 3.2 GtCO2 yr−1). Also, for 2024, GATM was 7.9 ± 0.2 GtC yr−1 (3.73 ± 0.1 ppm yr−1), 2.2 GtC above the 2023 growth rate. SOCEAN was 3.4 ± 0.4 GtC yr−1 and SLAND was 1.9 ± 1.1 GtC yr−1, leaving a large negative BIM (−1.7 GtC yr−1), suggesting that the total sink or GATM is strongly overestimated in 2024. The global atmospheric CO2 concentration averaged over 2024 reached 422.8 ± 0.1 ppm. Preliminary data for 2025 suggest an increase in EFOS relative to 2024 of +1.0 % (0.2 % to 1.7 %) globally, and atmospheric CO2 concentration increasing by 2.1 ppm reaching 425.6 ppm, 53 % above the pre-industrial level (around 278 ppm in 1750). Overall, the mean and trend in the components of the global carbon budget are consistently estimated over the period 1959–2024, with a near-zero overall budget imbalance, although discrepancies of up to around 1 GtC yr−1 persist for the representation of annual to decadal variability in CO2 fluxes. Comparison of estimates from multiple approaches and observations shows: (1) a persistent large uncertainty in the estimate of land-use change emissions, (2) a low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) a discrepancy between the different methods on the mean ocean sink.
(Earth System Science Data. vol. 18, n° 1866-3508, pp. 3211–3288, 13/05/2026)
LMD, INSU - CNRS, X, IP Paris, SU, CNRS, ENS-PSL, PSL, ENPC, IP Paris, UEA, CICERO, UiO, AWI, VLIZ, MPI-M, WUR, LMU, CSIRO, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, BIOGEO, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, PMEL, NOAA, KIT, ASU, BIOS, UOR, MFRI, LGENS, INSU - CNRS, CNRS, ENS-PSL, PSL, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, PSL, UVSQ, CEA, INSU - CNRS, X, IP Paris, CNES, SU, CNRS, UPCité, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CNRM, INSU - CNRS, CNRS, Comue de Toulouse
Temporal Variability and Size-Fractionation of Trace Metals During a Diurnal Cycle in a Coastal System: The Case of Arcachon Bay
Coastal systems are vital to human societies, delivering numerous ecosystem services. However, human activities introduce contaminants, especially trace metals (TM) that contribute to their degradation. These environments are inherently dynamic and complex, characterized by rapidly occurring biogeochemical processes. As a consequence, highfrequency sampling is required to evaluate short-term TM dynamics. The hourly temporal variations in nine TM (V, Mn, Ni, Cu, Zn, Cd, Pb, Co and U) concentrations and sizepartitioning (<0.02, <0.2 µm, raw sample and in the suspended particulate matter) were investigated during a 27 h diurnal cycle within the Arcachon Bay (SW France). The results demonstrated that: (i) the TM were mainly represented in the potentially bioavailable fraction (<0.02 µm), except for Pb which remained predominantly associated with the particles, (ii) the temporal variability for U and V was only due to the mixing of water bodies contrarily to the 7 other TM, (iii) there was no clear influence of daytime conditions on TM concentration and/or size-partitioning, and (iv) a superimposition of multiple processes controlling TM speciation. Finally, the calculated risk quotients for species demonstrated an ecological risk for the marine biota for Co and Cu. These findings highlight the importance of high-frequency sampling combined with size-fractionation approaches to better resolve TM speciation dynamics, thereby helping to address the persistent knowledge gap in the distribution and biogeochemical cycling of TM between particulate, colloidal and truly dissolved phases in aquatic systems.
(Journal of Marine Science and Engineering, n° 2077-1312, 09/05/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
OntoPFAS: An Ontology for the Forever Chemicals
Per- and polyfluoroalkyl substances (PFAS) are synthetic chemical compounds used widely for fundamental everyday products such as textiles, household products, cosmetics, or food processing, thanks to their resistance to heat, water, and oil. However, it has recently been acknowledged that they represent a threat to human health and the environment, given their ability to persist and spread across multiple living organisms (including mammals, plants, and other fauna). They have been linked to different types of health issues, such as tumors and cancers. Given some recent availability of data, this manuscript presents OntoPFAS, the first formal ontology related to PFAS and their rela- tions with the environment and human exposure. The result of this work extensively reuses existing knowledge from different domains, is capable of answering relevant questions, and is compliant with the first PFAS measurements information available. We describe the reasons for this work, its design methodology, the quality of the proposed conceptualization, and the impact in terms of applications for several communities. The resource is available under a free access license: https://github.com/davide1797/PFAS.git.
(. vol. 16550, pp. 21-38, 08/05/2026)
UM, MISTEA, INRAE, Institut Agro, LIB, UBE, LIS, AMU, UTLN, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, PRODIG (UMR_8586 / UMR_D_215 / UM_115), UP1, IRD, SU, CNRS, UPCité
Which benefits of fluvial annex sediment analysis for quantifying and tracing industrial pollution along the Saône River?
In the context of river ecological restoration in Europe and in order to achieve a “good” ecological and chemical status in watercourses, it is essential to quantify the volumes of contaminated sediment accumulated in fluvial annexes, which may be remobilized during floods or human interventions. These assessments not only allow the evaluation of ecotoxicological risks, but also help to assess the ecological functions associated with reconnection to the main channel. The Saône River (France), the main tributary of the Rhône River in terms of hydro-sedimentary contributions, has been little studied from this perspective, despite numerous developments (dykes) that have profoundly altered the lateral connectivity of its main channel. A more in-depth knowledge of the Saône River is therefore clearly needed to guide effective and safe ecological restoration actions.The volumes of sediments accumulated in three fluvial annexes distributed along the Saône River were estimated by combining ground-penetrating radar (GPR) transects with sediment cores sampling. These sediment archives were characterized (grain-size, organic matter content, trace metal content) to reconstruct the temporal trends of metal accumulation, based on ¹³⁷Cs and ²¹⁰Pb dating. Depending on the site, these sediment sequences provide six to eight decades of records, extending back to the 1940s for the longest. These data allow quantification of contaminants stocks (trace metals) and estimation of the annual load of contaminated suspended matters by the river in each site.The study sites exhibit contrasting morphologies and varying levels of lateral connectivity with the main channel. These differences influence the sediment storage volumes within the fluvial annexes, ranging from 8,000 m³ to 100,000 m³. These results reveal metal enrichment since the 1940s, with a clear and well-documented increase in Cd, Cu, Pb and Zn during the post‑World War II economic expansion (1950s), reaching maximum concentrations during the 1970s. Their concentrations subsequently declined in the 1990-2000s before stabilizing at lower plateau values.A specific feature concerns the contamination history of Ag, most likely driven by the photographic industry, which presented a three-phase pattern: (i) regular increase in the 1970s and 1980s, (ii) successive peaks between 1986 and 1994, and (iii) a marked decline in the late 1990s-2000s, with the decline of silver. This typical signal was observed at all studied sites along the river, despite hydrological connectivity differences. These sedimentary record complement monitoring data, especially for trace metals that were difficult to quantify in the past. This study highlights the major influence of historical contamination sources that released polluted sediments at the basin scale over several decades. This reconstruction also has national-scale implications and complements records obtained by other research works (such as on the Seine or Garonne rivers), highlighting the extent and persistence of pollution linked with photographic product manufacturing in Western Europe before 2000. Together, these results provide an integrated understanding of sediment dynamics and contamination, offering key insights for future river management and restoration strategies.
(04/05/2026)
LEHNA, UCBL, ENTPE, CNRS, ENTPE, ENTPE, LEHNA IAPHY, LEHNA, UCBL, ENTPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EVS, ENS de Lyon, Mines Saint-Étienne MSE, IMT, UL2, UJML, INSA Lyon, INSA, UJM, UJM EPE, ENTPE, ENSAL, CNRS, ALLHiS, UJM, UJM EPE
Climatic mechanisms underlying a southwestern French Neanderthal refugium at the onset of the last glaciation
(Proceedings of the National Academy of Sciences of the United States of America. vol. 123, n° 0027-8424, pp. e2610884123, 04/05/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, PACEA, UB, CNRS, SapienCE, UiB
New insights into subaqueous paleoseismology from the preserved imprints of paleo-earthquake markers on a normal fault scarp (Roseau Fault Lesser Antilles, France)
Assessment of seismic and tsunami hazards along coastlines requires knowledge of past earthquakes and their recurrence times along active submarine faults. To this end, subaqueous paleoseismological studies are performed and are based on sediment cores and seismic reflection images of faults. However, local site conditions sometimes preclude coring or seismic surveys and, even when possible, the resulting data may be limited. In addition to traditional geophysical and sedimentological data, seafloor geophysical data from submersibles can help elucidate the paleoseismic history of submarine faults. Here, we conducted a near-bottom geological survey using a Remotely Operated Vehicle (ROV) along the Roseau normal fault (Lesser Antilles, France) to study the fine morphology and paleoseismic history of an active submarine fault scarp. This fault hosted the Mw 6.3 2004 Les Saintes earthquake and shows a coseismic ribbon at its base. We used the submersible data to map and characterize several scarp morphologies including abrasion bands, notches, roughness changes, dark bands, and uplifted sediments along the fault scarp. We propose that these markers, which all formed at the seafloor, can ultimately be used to reconstruct the exhumation history of the fault scarp, because they are linked to base level changes (i.e. sedimentation and tectonic exhumation). At one site along the Roseau fault, the scarp’s detailed morphology can be explained by the occurrence of three earthquakes coupled to several episodes of rapid sedimentation. The penultimate earthquake may have generated a vertical offset of 3 m, where at the same location the 2004 event slipped by ~1.4 m. The penultimate earthquake was at least as energetic as the 2004 event, the Roseau fault being able to host a M7 event if broken entirely. Sediment rates from cores sampled near the fault show that the penultimate earthquake probably occurred within the past ~2.8 kyr. These observations highlight the potential of studying offshore faults with ROV optical imagery to better understand the seismic history of crustal faults.
(03/05/2026)
GEOAZUR 7329, INSU - CNRS, UniCA, CNRS, IRD [Occitanie], IRD, UniCA, IPGP - UMR_7154, INSU - CNRS, IGN, UR, IPG Paris, CNRS, UPCité, LGENS, INSU - CNRS, CNRS, ENS-PSL, PSL, GFZ, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, iSTeP, INSU - CNRS, SU, CNRS, CY