Combined Atmospheric and Marine Heatwaves Exacerbate the Impacts of a Non-Indigenous Species, the Asian Date Mussel Arcuatula Senhousia, on Benthic Ecosystem Functioning
Climate change is predicted to increase the frequency, severity, and duration of extreme climatic events such as heatwaves. Benthic organisms inhabiting intertidal flats are subjected to both marine and atmospheric heatwaves and can experience extreme temperature variations over relatively short periods of time. Non-indigenous species are generally capable to cope with extreme events more efficiently that native species. The Arcachon bay, a lagoon located along the French Atlantic coast is currently colonised by the invasive mussel, Arcuatula senhousia. In this study, we investigated how these two stressors (non-indigenous species colonisation and heatwaves) affect soft-bottom ecosystem functioning. We conducted two seasonal laboratory experiments to investigate the effects of combined marine and atmospheric heatwaves on the biogeochemical dynamics of sediments colonised by A. senhousia at different densities. More precisely, we assessed the community scale responses by measuring nutrients (NOx, NH4+, PO43-) and oxygen fluxes across the sediment-water interface. The results highlight that (1) heatwaves affect oxygen and nutrient exchanges across the sediment-water interface, (2) the magnitude of these effects can be strongly enhanced by increasing densities of A. senhousia, and (3) a marked seasonal-dependence. These results emphasise that the interaction between the seasonality of heatwave occurrence, its intensity and the level of colonisation by non-indigenous ecosystem engineers likely shape their consequences for ecosystem functioning. Our results thus reinforce previous findings suggesting that climate change may profoundly exacerbate the effects of biological invasions.
(Marine Environmental Research. vol. 212, n° 0141-1136, pp. 107560, 01/11/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, PatriNat, MNHN, IRD, CNRS, OFB - DSUED, OFB, LERAR, COAST, IFREMER
Confounding factors affect hemocyte responses of mussels Mytilus galloprovincialis upon foodborne exposure to polystyrene nanoplastics of three sizes
Information regarding the impact of nanoplastics (NPs, ≤ 1 μm) on marine organisms is insufficient. This work aimed to investigate the differential toxicity of three sizes of polystyrene (PS) NPs (50, 200 and 1000 nm) on the hemocytes and condition index (CI) of sentinel marine mussels Mytilus galloprovincialis. Mussels were dietarily exposed for 7 days through microalgae to PS at a low dose (LD: 103 NPs/mL) and a high dose (HD: 108 NPs/mL of 50 and 200 nm NPs, and 106 NPs/mL of 1000 nm NPs). Each experiment (E) was performed twice, as follows: E1 and E4 for 50 nm PS NPs, E2 and E5 for 200 nm PS NPs and E3 and E6 for 1000 nm PS NPs. Despite the six experiments were run in less than a month, there were significant differences between the independent experiments of the different sizes of PS NPs. No differences in CI were found within each experiment, but differences were observed between independent experiments, possibly due to the spawning events observed during the acclimation of mussels of E3-E4. Similarly, a higher ROS production occurred in hemocytes of control mussels of E3-E4 compared to E1-E2 and E5-E6. But no differences in ROS were recorded in NPs treatments compared to controls within experiments. Cell viability of control hemocytes decreased in E3-E4 and E5-E6 in comparison to E1-E2. This could mask the size-dependent response to the NPs, as in E1 hemocytes showed lower viability and phagocytic activity than those from control mussels, but not in E4. Similarly, hemocytes of mussels exposed to HD in E2 showed lower viability than controls, but the contrary was observed in E5. In conclusion, a trend for size-dependent effects on mussel hemocytes was observed. However, hemocyte responses varied along time, possibly due to seasonal variations in mussels physiology connected with the gametogenic cycle.
(Science of the Total Environment. vol. 1003, n° 0048-9697, 01/11/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UB, UPV / EHU
New mammal assemblage from last interglacial in Argentine Pampas: Debating biostratigraphic and biochronological reliability
This study analyzes one of the most complete mammalian fossil records from the Middle to the end of the Pleistocene in the Pampean Region, recovered from the Salto de Piedra Paleontological Locality along Tapalqué Creek. The site preserves a fluvial-palustrine sequence with six depositional units (U1-U6), separated by erosive unconformities or pedogenetic horizons. Radiometric dating (OSL and AMS 14 C), integrated with sedimentological and faunal data, allows correlation with Marine Isotope Stages: Unit 1 (MIS 6-5; >127 ka), Unit 2 (MIS 3; ~40.5 ka), Units 3-4 (MIS 2; 38-11.2 ka), and Units 5-6 (MIS 1; 12.6-7.8 ka). Three fossil assemblages were identified (U1, U3-4, U5-6), primarily linked to fluvial channels. The record provides critical biochronological information, with fossils showing minimal weathering and abrasion, and no evidence of reworking. The occurrence of Equus neogeus in U1 (>127 ka) expands the lower limit of its biozone back to ~300 ka. Index taxa in Unit 1-Glyptodon munizi, Megatherium americanum, Equus neogeus-highlight biozone overlap, challenging the stratigraphic resolution of traditional schemes. Due to the lack of exclusive taxa and overlapping ages, we propose merging the Bonaerean with the Lujanian Stage/Age (~300-11.6 ka). These findings call for a revision of Quaternary biozone frameworks in South America and improve biostratigraphic resolution for the Pampean fossil record.
(Quaternary Science Reviews. vol. 367, n° 0277-3791, 01/11/2025)
UV, MNCN, CSIC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CRILAR, UR, UC3M
Epigenetic regulation of sex: the role of DNA methylation and zbtb38 in zebrafish sex differentiation and heat-induced masculinization
There is increasing evidence that global change can threaten biodiversity by inducing skewed sex ratios. Accumulating evidences support a role of epigenetics, mainly DNA methylation, in sex differentiation. The aim of the present work was to investigate the potential role of zbtb38, a transcriptional factor that binds to methylated promoters, in sex differentiation and/or maintenance in zebrafish. We analyzed the methylation and transcription level of zbtb38 in males, females and undifferentiated individuals raised at standard or high temperature, a masculinizing factor. Results were compared to those obtained for genes already known to be involved in sex differentiation/maintenance (cyp19a1a, foxl2a, dmrt1). All genes presented a sex-specific pattern of DNA methylation and transcription but the most significant differences between sexes were observed for zbtb38. Moreover, a highly significant positive correlation was observed between the methylation level of zbtb38 and cyp19a1a, which encodes an enzyme that converts androgens into estradiol. However, while the hypermethylation of cyp19a1a was associated with its down-regulation, an inverse relationship was observed for zbtb38, providing a basis for mutual antagonism. Furthermore, zbtb38 was the only gene for which its transcription level was affected by temperature, being up-regulated in females that escaped to masculinization. Finally, despite embryos presented a paternal methylome, zbtb38 was the only gene for which its methylation level rapidly changed during early development to reach intermediate values between males and females at the larval stage, ie a bi-potential state. Our results strongly support a strategic role of DNA methylation and zbtb38 in sex differentiation and maintenance.
(Molecular and Cellular Endocrinology. vol. 609, n° 0303-7207, pp. 112636, 01/11/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Physicochemical footprint of an H2-enriched water leakage in a shallow freshwater aquifer
Underground hydrogen storage (UHS) is considered a promising solution for balancing renewable energy production, but potential leakage into shallow aquifers raises concerns about water quality and subsurface safety. This underscores the need to identify reliable monitoring indicators capable of detecting H 2 in various hydrogeological contexts. This study investigates the behavior of H 2 -enriched water injected into a shallow freshwater carbonate aquifer under controlled conditions at an experimental site located in an underground limestone quarry in Saint-Émilion (France). A 200-liter volume of H 2 -enriched water was injected, and its migration was tracked over 8 days using a combination of in-situ physico-chemical probes and manual water sampling across several downstream wells. Among the monitored physico-chemical parameters (pH, ORP, dissolved oxygen, conductivity), only the oxidation-reduction potential (ORP) showed a consistent and measurable response beyond the injection point, even at 5-7 m downstream. Dissolved H 2 concentrations decreased rapidly with distance, and no significant geochemical reactions (e.g., sulfate or nitrate reduction, calcite dissolution/precipitation) were observed. These results suggest that while pH and dissolved O 2 may help characterize the presence of dissolved H 2 near the leak, ORP remains the most reliable indicator for tracking H 2 migration in the aquifer in these experimental conditions. This study offers new insights into the behavior of H 2 in shallow carbonate aquifers and supports the integration of ORP monitoring into operational strategies for early leakage detection at UHS sites.
(International Journal of Hydrogen Energy. vol. 193, n° 0360-3199, 01/11/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
It’s about time: integrating micro- and macro-evolutionary perspectives into ecotoxicology for improved predictions and long-term assessment of ecosystem health
Whilst ecology has served as a foundational inspiration for risk assessment in ecotoxicology, far less attention has been given to evolution, despite its importance. As the need for a new paradigm in ecotoxicology is becoming increasingly evident in the face of Global change, the consideration of evolutionary processes and patterns should provide a way to progress towards this objective. This review draws on the recent literature to feed this idea, with a particular attention to the interplay between evolutionary paces. Doing so, we recast ecotoxicology as an innovative, exciting discipline, conceptually equipped to meet the challenges of the Anthropocene era.
(Current Opinion in Environmental Science & Health. vol. 48, pp. 100688, 01/11/2025)
LIENSs, INSU - CNRS, ULR, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, DECOD, IFREMER, INRAE, Institut Agro, Institut Agro
Cushion Presence and Species Pools Mitigate the Effect of Climate on Species Richness in Alpine Communities
Abiotic and historical factors are major determinants of large-scale patterns of species richness, yet facilitative interactions can strongly influence diversity in low-productivity habitats such as alpine ecosystems. Cushion plants often promote the establishment of other species, but the relative roles of climate, species pools, and facilitation remain largely unknown. We analyzed 454 plots (4 × 4 m each) of vascular plants from the subnival belts of the Qinghai-Tibet Plateau, using generalized linear mixed models and structural equation modeling. Community species richness was shaped by climate, regional species pools, and cushion presence, with cushions exerting the strongest positive effect in the Hengduan Mountains and Tibetan Plateau. In the structural equation model, cushion presence exerted the strongest positive effect on species richness, whereas climate affected species richness mainly through indirect pathways: wetter conditions enlarged species pools, whereas colder conditions increased cushion presence, which in turn enhanced local species richness. Cushions also buffered the negative effects of aridity. In contrast, species richness variation in the relatively wetter regions of the Himalaya was primarily determined by abiotic factors but not by cushion presence, consistent with the dominant assumption that facilitation is not frequent under favorable climatic conditions. Our findings demonstrate that alpine species richness emerges from the combined effects of species pools and facilitation rather than direct climate effects alone, highlighting the need to integrate biotic and abiotic drivers when explaining biodiversity patterns in extreme environments.
(Research. vol. 8, n° 2096-5168, 30/10/2025)
SEU, CAAS, ICT, IBMC, UNISTRA, CNRS, UNISTRA, CNRS, I2CT, IBMC, UNISTRA, CNRS, UNISTRA, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UAB
Vegetation and fire regimes in the Neotropics over the last 21 000 years
Vegetation and fire activity have dynamically changed in response to past variations in global and regional climate. Here we investigate these responses across the Neotropics based on the analysis of modern vegetation distribution and fire activity in relation to modern climate patterns, and a compilation of 255 vegetation records and 131 charcoal records encompassing the last 21 000 years before present (ka) in relation to past climate changes. Our analyses on the dynamics of past tree cover and fire activity focus on seven subregions: (1) northern Neotropics (NNeo); (2) tropical Andes (TrAn); (3) Amazonia; (4) northeastern Brazil (NEB);
(5) central-eastern Brazil (CEB); (6) southeastern South America (SESA); and (7) extratropical Andes (ExTrAn). The regionalized assessment unveils spatial heterogeneity in the timing and controls of vegetation and fire dynamics. Temperature, atmospheric CO 2 concentrations, and precipitation exhibit distinct and alternating roles as primary drivers of tree cover and fire regime changes with additional impacts from human activity. During the Last Glacial Maximum (LGM, here covering 21-19 ka), arboreal growth in high elevation sites (TrAn) and in sub-and extra-tropical latitudes (SESA and ExTrAn) was mainly limited by low temperatures and atmospheric CO 2 concentrations, while fuel-limited conditions restrained fire activity. In warmer tropical regions (NNeo, Amazonia, CEB), moisture availability was likely the main controlling factor of both vegetation and fire, with the effects of low CO 2 amplifying these constraints. Throughout the deglacial phase (19-11.7 ka), progressive warming and increasing atmospheric CO 2 concentrations fostered a gradual biomass expansion, and together these changes led to intensified fire activity in the sub-and extra-tropical temperature-limited regions. Meanwhile, increased (decreased) precipitation associated with millennial-scale events favored increases (decreases) in tree cover in regions such as CEB and NEB (NNeo). Between 14-13 ka, most southern latitude subregions (Amazonia, CEB, SESA, ExTrAn) saw a rise in fire activity coeval with a second rapid warming, contrary to decreased fire activity in NNeo amid relatively wetter conditions. Throughout the Holocene, when temperature and atmospheric CO 2 fluctuations were lower, shifts in precipitation became the primary driver of vegetation and fire dynamics across all the Neotropics. Changes in the Intertropical Convergence Zone and gradual intensification of the South American Summer Monsoon throughout the Holocene favored a continuous increase in tree cover over Amazonia, CEB, and SESA, but led to a forest cover decrease in NNeo and NEB. From the earlyto the mid-Holocene, the strengthening of the Southern Westerly Winds promoted vegetation expansion and fire regime weakening in ExTrAn. In the late Holocene, human impacts became more pronounced, with a clearer effect on regional tree cover and fire activity, particularly in NNeo and TrAn.
(Earth System Dynamics. vol. 16, n° 2190-4979, pp. 1887 - 1921, 29/10/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, USP, CNPEM, USP, MIO, IRD, AMU, INSU - CNRS, UTLN, CNRS, UFSCar
Caractérisation, vulnérabilité et exploitabilité des aquifères captifs ou sous couverture sédimentaire : approche transdisciplinaire du projet DEESAC
Les nappes captives, naturellement protégées par des couches imperméables, représentent une ressource en eau souterraine relativement peu exploitée, caractérisée par des eaux souvent de bonne qualité et une inertie face aux fluctuations climatiques. Le principal enjeu réside donc dans leur exploitation soutenable et durable. Malgré de larges stocks, leur exploitation combinée à de faibles taux de renouvellement, peut entraîner un épuisement de la ressource, et une dégradation de la qualité de l’eau (activités industrielles et agricoles, mobilisation d’éléments chimiques géogéniques). Leur utilisation stratégique pour l’alimentation en eau potable impose une gestion dédiée. Le projet DEESAC (Durabilité et Exploitabilité des Eaux Souterraines des Aquifères Captifs ou sous Couverture ; 2023 à 2027) s’inscrit dans le programme de recherche OneWater – Eau Bien Commun, vise à explorer les potentialités et les limites de l’exploitation durable des eaux souterraines issues d’aquifères captifs ou sous couverture en France. Le projet a pour objectif de conduire des recherches transdisciplinaires combinant géologie, géophysique, hydrogéologie, géochimie, mais également sociologie et sciences de gestion, tout en en mobilisant des acteurs de l’eau. Les objectifs du projet sont multiples : mieux comprendre le fonctionnement hydrogéologique et géochimique de ces nappes, identifier les conditions de leur renouvellement, évaluer leur vulnérabilité, et co-construire avec les parties prenantes — gestionnaires, agences, syndicats des eaux — afin de développer des outils de gestion. Cela comprend l’élaboration d’indicateurs pertinents, de seuils d’exploitation acceptables, et d’un guide méthodologique à destination des gestionnaires et décideurs. Ce travail a bénéficié d'une aide de l’État gérée par l'Agence Nationale de la Recherche au titre de France 2030 portant la référence 22-PEXO-0010.
(27/10/2025)
BRGM, CEREGE, IRD, AMU, CdF (institution), INSU - CNRS, CNRS, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR G-EAU, Cirad, BRGM, IRD, INRAE, Institut Agro, UM, UM, INAT, Cirad, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS
New insights on the regional architecture and dynamics of mixed fluvio-aeolian deposits from Middle Buntsandstein in the southern margin of the German Basin
(pp. 658920, 27/10/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IFPEN, Bordeaux INP, GR, UR, INSU - CNRS, CNRS