Physiological effects of PFAS exposure in seabird chicks: A multi-species study of thyroid hormone triiodothyronine, body condition and telomere length in South Western France
There is growing evidence that poly and perfluoroalkyl substances (PFAS) exposure leads to the disruption of thyroid hormones including thyroxine (T4) and triiodothyronine (T3), and may affect telomeres, repetitive nucleotide sequences which protects chromosome ends. Many seabird species are long-lived top predators thus exhibit high contaminant levels, and PFAS-disrupting effects on physiology have been documented especially in relation to the endocrine system in adults. On the contrary, studies on the developmental period (i.e., chicks), during which exposure to environmental contaminants may have a greater impact on physiological traits, remain scarce to this date. We carried out a multi-species study with the aim to assess whether and to which extent chicks of four gull species (herring gull, great and lesser black-backed gull, yellow-legged gull) in South Western France are contaminated by PFAS, and to bring further evidence about their potential physiological consequences. Linear PFOS showed concentrations of concern as it was generally >10 times higher than the other PFAS, and exceeded a threshold toxicity level (calculated from previous studies in birds) in almost all sampled chicks. Nonetheless, in herring gull male chicks, total T3 levels were significantly and negatively associated with perfluorodecanoate (PFDA) and perfluorododecanoate (PFDoDA) and positively associated with perfluorotetradecanoate (PFTeDA) in female chicks. Total T3 levels were also positively associated with PFDoDA in great black backed gull male chicks and with perfluorotridecanoate (PFTrDA) in lesser black backed gull chicks. In lesser and great black-backed gulls, both females and males showed significant negative associations between several PFAS and their body condition, and a positive association between telomere length and L-PFOS in the yellow-legged gull. These results corroborate previous findings and need to be further explored as they suggest that PFAS may interfere with the physiological status of chicks during the developmental period, potentially inducing long-lasting consequences.
(Science of the Total Environment. vol. 901, n° 0048-9697, pp. 165920, 25/02/2026)
PhyMA, MNHN, CNRS, CEBC, ULR, CNRS, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Sampling terrigenous diffuse sources in watercourse: Influence of land use and hydrological conditions on dissolved organic matter characteristics
Diffuse and point sources of dissolved organic matter (DOM) in streams influence its composition, interactions and fate in the aquatic ecosystem. These inputs can be very numerous at the scale of a watershed, and their identification remains a challenge, especially for diffuse sources related to land use. The complexity of the transfer mechanisms and the reactivity of DOM throughout the soil-water column continuum raise questions about the sampling of diffuse sources in watercourses. To answer this issue, we compared the characteristics of soil-extracted DOM influenced by a particular land use (homogenous sub-catchment of forest and vineyard) and DOM collected from the watercourse adjacent to the soil samples. A 28-day incubation experiment of soil extracts was designed to remove the labile fraction of DOM. During the first 3 days, between 40 and 70 %of the DOC mass was lost for both types of soils. A set of optical indicators (UV–Visible, EEM fluorescence and HPSEC/UV-fluorescence) showed that the labile fraction was mostly composed by low (<1 kDa) and high (>10 kDa) protein-like molecules. At the end of the incubation, soil-extracted DOMwas mainly composed of medium molecules (1–10 kDa) associated to terrigenous humic-like compounds. Its optical and size molecular signature tended towards that in the adjacent watercourses and was specific to land use.However, the characteristics of DOMin watercourses was also influenced by the hydrological conditions, probably due to a transfer of top soil DOM during high water periods and both deep soil and autochthonous DOM during low water periods. These results were obtained by a set of indicators, including novel ones derived from HPSEC/UV-fluorescence. Finally, this study demonstrated that it is possible to sample the DOM representative of a land use directly in the river downstream of the homogeneous sub-basin by multiplying the samples during contrasting hydrological conditions.
(Science of the Total Environment. vol. 872, n° 0048-9697, pp. 162104, 25/02/2026)
RiverLy, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Marine diatoms record Late Holocene regime shifts in the Pikialasorsuaq ecosystem
Abstract The Pikialasorsuaq (North Water polynya) is an area of local and global cultural and ecological significance. However, over the last decades, the region has been subject to rapid warming, and in some recent years, the seasonal ice arch that has historically defined the polynya's northern boundary has failed to form. Both factors are deemed to alter the polynya's ecosystem functioning. To understand how climate‐induced changes to the Pikialasorsuaq impact the basis of the marine food web, we explored diatom community‐level responses to changing conditions, from a sediment core spanning the last 3800 years. Four metrics were used: total diatom concentrations, taxonomic composition, mean size, and diversity. Generalized additive model statistics highlight significant changes at ca. 2400, 2050, 1550, 1200, and 130 cal years BP, all coeval with known transitions between colder and warmer intervals of the Late Holocene, and regime shifts in the Pikialasorsuaq. Notably, a weaker/contracted polynya during the Roman Warm Period and Medieval Climate Anomaly caused the diatom community to reorganize via shifts in species composition, with the presence of larger taxa but lower diversity, and significantly reduced export production. This study underlines the high sensitivity of primary producers to changes in the polynya dynamics and illustrates that the strong pulse of early spring cryopelagic diatoms that makes the Pikialasorsuaq exceptionally productive may be jeopardized by rapid warming and associated Nares Strait ice arch destabilization. Future alterations to the phenology of primary producers may disproportionately impact higher trophic levels and keystone species in this region, with implications for Indigenous Peoples and global diversity.
(Global Change Biology. vol. 29, n° 1354-1013, pp. 6503-6516, 25/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Simulation of organic aerosol, its precursors, and related oxidants in the Landes pine forest in southwestern France: accounting for domain-specific land use and physical conditions
Organic aerosol (OA) still remains one of the most difficult components of the atmospheric aerosols to simulate, given the multitude of its precursors, the uncertainty in its formation pathways, and the lack of measurements of its detailed composition. The LANDEX (LANDes Experiment) project, during its intensive field campaign in summer 2017, gives us the opportunity to compare biogenic secondary OA (BSOA) and its precursors and oxidants obtained within and above the Landes forest canopy to simulations performed with CHIMERE, a state-of-the-art regional chemistry transport model. The Landes forest is situated in the southwestern part of France and is one of the largest anthropized forests in Europe (1×106 ha). The majority of the forest is comprised of maritime pine trees, which are strong terpenoid emitters, providing a large potential for BSOA formation. In order to simulate OA buildup in this area, a specific model configuration setup adapted to the local peculiarities was necessary. As the forest is nonhomogeneous, with interstitial agricultural fields, high-resolution 1 km simulations over the forest area were performed. Biogenic volatile organic compound (BVOC) emissions were predicted by MEGAN, but specific land cover information needed to be used and was thus chosen from the comparison of several high-resolution land cover databases. Moreover, the tree species distribution needed to be updated for the specific conditions of the Landes forest. In order to understand the canopy effect in the forest, canopy effects on vertical diffusivity, winds, and radiation were implemented in the model in a simplified way. The refined simulations show a redistribution of BVOCs with a decrease in isoprene and an increase in terpenoid emissions with respect to the standard case, both of which are in line with observations. Corresponding changes to simulated BSOA sources are tracked. Very low nighttime ozone, sometimes near zero, remains overestimated in all simulations. This has implications for the nighttime oxidant budget, including NO3. Despite careful treatment of physical conditions, simulated BSOA is overestimated in the most refined simulation. Simulations are also compared to air quality sites surrounding the Landes forest, reporting a more realistic simulation in these stations in the most refined test case. Finally, the importance of the sea breeze system, which also impacts species concentrations inside the forest, is made evident.
(Atmospheric Chemistry and Physics. vol. 23, n° 1680-7316, pp. 3679-3706, 25/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LISA (UMR_7583), INSU - CNRS, UPEC UP12, CNRS, UPCité, LMD, INSU - CNRS, X, IP Paris, ENPC, SU, CNRS, ENS-PSL, PSL, IMBE, AU, AMU, CNRS
Clogging detection and productive layers identification along boreholes using Active Distributed Temperature Sensing
Fiber-Optic Active Distributed Temperature Sensing (FO-ADTS) experiments were performed on an Aquifer Thermal Energy Storage system (ATES) site located on the university campus of Bordeaux, France. The experiments consisted in heating the steel core of the FO cable while monitoring the rate of temperature increase during the heating periods. The changes in temperature, that were monitored through time at every depth under various hydraulic conditions and in different boreholes, were used to evaluate both aquifer properties and wells conditions. A first ADTS experiment was conducted under cross borehole configuration using a pumping well and a monitoring well separated by a distance of 8.5 meters. Then, to check the reciprocity of the results, a second experiment was conducted by switching the monitoring and the pumping well. The results obtained through the use of analytical solutions for reproducing and interpreting the data lead to the following conclusions: (i) ADTS can be used to estimate both thermal conductivity and Darcy velocity distribution along boreholes, crucial properties for ATES performance. (ii) The proposed method is a promising tool to detect clogging locations in the boreholes when it occurs. This can be of great practical interest to maintain systems performance, since, once FO cables deployed, experiments could be easily repeated without opening boreholes and stop the system operation.
(Journal of Hydrology. vol. 617, n° 0022-1694, pp. 129113, 25/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GR, UR, INSU - CNRS, CNRS
Natural remobilization and historical evolution of a modern coastal transgressive dunefield
The vast majority of coastal dunes in Europe have been stabilized by increasing vegetation cover since the mid‐20th century. However, some systems may experience a remobilization phase, generally occurring locally and further propagating alongshore, the drivers of which remain poorly documented. This study investigates the evolutionary paths (stabilization/destabilization/remobilization) from 1945 to 2020 of a 2 km‐long modern coastal transgressive dunefield located in southwest France with a holistic approach (GPR profiles, aerial photographs and LiDAR topographic data). Results show a landward migration of the transgressive dune by approximately 233 ± 7.5 m, through two distinct stages of rapid landward migration from 10 to 23 m/yr (Stage I: 1949–1959 and Stage III: 2000–2021) separated by an approximately 40‐year stage of slow to no migration, but with substantial windward slope deflation (Stage II). The onset of Stage II is due to the fixation of vegetation by human action between 1950 and 1959. The onset of Stage III is hypothesized to be driven by long and sustained upper backshore/dune toe erosion beginning in 1968 due to a massive shoal welding that locally disturbed the longshore drift. It induced a destabilization of the dune and erosion of the vegetation cover over some decades. A non‐synchronization is therefore observed between the start of the perturbation (1968), then the migration (2000), in line with the hysteresis concept of Tsoar (2005). This study shows that almost all of the sedimentary volume of the 1945 dune has been remobilized by translation to shape the dune system in its current form. The 2.2 km dunefield has grown by approximately 673 000 ± 190 000 m 3 during the 2005–2020 period. Among this volume, there is a new foredune that was built from 2005 between the upper beach and the transgressive dune (volume in 2020 of about 394 000 ± 68 000 m 3 ).
(Earth Surface Processes and Landforms. vol. 48, n° 0197-9337, pp. 1064 - 1083, 25/02/2026)
CEFREM, UPVD, INSU - CNRS, CNRS, BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ONF
U–Pb age constraints on the Carboniferous-Permian transition in continental basins of eastern equatorial Pangaea (France): implications for the depositional history and correlations across the late Variscan Belt
Intramountain late Carboniferous–Permian basins of western Europe developed during the latest orogenic stages of the Variscan Mountain Belt in eastern Pangaea, at equatorial palaeolatitudes. Their stratigraphic framework is mainly based on continental subdivisions (e.g. Stephanian and Autunian continental stages), which can be contentious due to biostratigraphic biases, resulting in long-distance diachronous subdivisions. To provide precise inter-basinal and global correlations to the internationally recognized chronostratigraphic marine stages, this study reports new U–Pb geochronology from the Aumance and Decize–La Machine basins, located in the northern French Massif Central. Zircon grains extracted from three volcanic ash-fall layers give weighted mean 206 Pb/ 238 U ages of 299.11 ± 0.35 Ma; 298.73 ± 0.36 Ma and 298.59 ± 0.35 Ma (2σ total propagated uncertainty) by the chemical abrasion–isotope dilution–thermal ionization mass spectrometry (CA-ID-TIMS) method, coinciding with the Carboniferous–Permian transition (Gzhelian and Asselian stages). These ages imply that the northern Massif Central basins developed synchronously in relatively short periods of time (<10 Myr), reflecting substantial sedimentation rates. Finally, the new chronology of infilling of these basins confirms that they were connected during the late Carboniferous and early Permian periods, improving the knowledge on the late-orogenic Variscan geodynamic setting in this area
(Journal of the Geological Society. vol. 180, pp. jgs2023-075, 25/02/2026)
GR, UR, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UniCa, MIT, BRGM, BGS, UB, CNRS
Quaternary sedimentary processes on the Bahamas: From platform to abyss
Understanding the interaction between sediment production on and export from shallow-water areas of platforms and slopes is primordial when assessing sedimentary processes on a carbonate-platform scale. In this manuscript we explore variations in facies, sediment export, sediment deposition and reorganisation, hydroacoustic- and small-scale sedimentary structures, but also assess the variability in current systems as observed during the Quaternary for the north-facing margin of Little Bahama Bank (LBB) and compare those characteristics with features observed on other slopes surrounding LBB and Great Bahama Bank (GBB). Over the past decade, the northern margin of LBB was explored during a series of oceanographic cruises of the CARAMBAR project, which included the collection of 24.270 km2 of bathymetry data, 6.398 km of very high-resolution seismic profiles, and 42 cores covering water depths ranging from 177 m to 4873 m. This study evaluates the results obtained from the analysis of sediment cores retrieved in the Great Abaco Canyon area (GAC), located between the lower northern LBB slope, which is connected to the abyssal plain. The analysis of the shallower parts of the LBB slope relies on earlier studies and are complementary to our data, and allow for a detailed analysis of the sedimentary processes acting along the entire LBB slope. The data reveal that Quaternary sediment distribution differs when moving from the north-eastern to the north-western LBB slope. The entire LBB slope is dissected by numerous canyons. Gravity processes enriched in coarse platform components occur infrequently and are concentrated within lobes in the east. Only coarse-grained rich bank facies can concentrate coarse grains on this margin. The western LBB slope is mostly influenced by fine-grained platform export and current circulation. The deeper GAC area is dominated by pelagic sediments that are supplied from the canyon sides and through tributaries. The sediment composition confirms that pelagic sediment production and current movements determine the sediment-deposition and redistribution processes at this site. The comparison with other Bahamian slopes demonstrates that a leeward position agrees with high sedimentation rates on the slopes resulting in specific morphologic structures, such as gullies and sediment waves, related to fine-grained sediment export, whereas platform-derived coarse-grained facies are deposited downstream in larger structures, such as canyons, that are not affected by the main wind direction. Slope angle could also have an impact on grain-size export, as it appears that coarse-grained deposits are frequent on steep slopes like those bordering the Exuma Sound basin.
(Marine Geology. vol. 459, n° 0025-3227, pp. 107044, 25/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, VU, OSU PYTHEAS, IRD, AMU, INSU - CNRS, CNRS, INRAE, UHH, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France], [Total Energies. Anciennement : Total, TotalFina, TotalFinaElf]
Monitoring the Temporal Evolution of the Floods in the Lower Mekong Basin using Multisatellite Observations
Surface water storage is an essential component of the hydrological cycle. Remote sensing offers valuable tools for monitoring both surface water extent from satellite images and water levels from radar altimetry. Combining both information, we were able to estimate the variations of surface water extent and storage in the Lower Mekong Basin from 2000 to 2020. Signatures of the extreme climatic events - floods from 2000 to 2002, of 2011, drought of 2015 clearly appear on both extent and storage. The mean amplitude of these variables shows a strong decrease when comparing the periods of 2000–2010 and 2011–2020. Between these two periods, a large reduction of the annual average number of days with the presence of floods can be observed in most of the Lower Mekong Basin, except around the Tonle Sap (Cambodia) and in some parts of the delta.
(pp. 5877-5880, 25/02/2026)
UMR ISPA, Bordeaux Sciences Agro, INRAE, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, OASU, UB, INSU - CNRS, ULR, CNRS, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, USTH, LERMA, ENS-PSL, PSL, INSU - CNRS, CNRS, PSL, SU, CNRS, CY, GET, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS
High contamination of a sentinel vertebrate species by azoles in vineyards: a study of common blackbirds (Turdus merula) in multiple habitats in western France
Azoles represent the most used family of organic fungicides worldwide and they are used in agriculture to circumvent the detrimental impact of fungi on yields. Although it is known that these triazoles can contaminate the air, the soil, and the water, field data are currently and dramatically lacking to assess if, and to what extent, the use of triazoles could contaminate non-target wild vertebrate species, notably in agroecosystems. In this study, we aimed to document for the first time the degree of blood contamination of a generalist wild bird species by multiple azoles which are used for plant protection and fungi pest control in various habitats. We deployed passive air samplers and captured 118 Common blackbirds (Turdus merula) in an agroecosystem (vineyard), a protected forest, and a city in western France. We collected blood and analyzed the plasma levels of 13 triazoles and 2 imidazoles. We found that a significant percentage of blackbirds living in vineyards have extremely high plasma levels of multiple azoles (means (pg.g⁻¹); tebuconazole: 149.23, difenoconazole: 44.27, fenbuconazole: 239.38, tetraconazole: 1194.16), while contamination was very limited in the blackbirds from the protected forest and absent in urban blackbirds. Interestingly, we also report that the contamination of blackbirds living in vineyard was especially high at the end of Spring and the beginning of Summer and this matches perfectly with the results from the passive air samplers (i.e., high levels of azoles in the air of vineyards during June and July). However, we did not find any correlation between the levels of plasma contamination by azoles and two simple integrative biomarkers of health (feather density and body condition) in this sentinel species. Future experimental studies are now needed to assess the potential sub-lethal effects of such levels of contamination on the physiology of non-target vertebrate species.
(Environmental Pollution. vol. 316, n° 0269-7491, pp. 120655, 25/02/2026)
CEBC, ULR, CNRS, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS