Ozone production in a maritime pine forest in water-stressed conditions
During two growing seasons of a maritime pine stand, in 2014 and 2015, ozone (O-3) fluxes have been determined using the eddy covariance (EC) method and compared to the outputs of a big-leaf O-3 deposition model including stomatal, cuticular and soil pathways. The model developed in this study generally allowed to properly reproduce the measured ozone deposition. Ozone fluxes showed a strong reduction during two water stressed periods in September 2014 and July 2015. The model partly explain this fall due to the reduction of stomatal deposition. Despite this stomatal closure, measured O-3 fluxes presented systematically lower negative values than the model outputs, and sometimes even positive values around midday during periods marked by strong water stress. In other words, the difference between observed and modelled O-3 fluxes (hereinafter referred to as the residual O-3 flux) is systematically positive on daytime during these water-stressed periods. This positive residual flux traduced the existence of an O-3 source below the flux measurement level, responsible for positive fluxes that counterbalance deposition fluxes. We developed an O-3 production module based on a terpene emission algorithm and an OH concentration proxy, to try to explain the observed ozone production. As this parametrisation allowed us to reproduce well the daily and inter-daily dynamics of the residual O-3 flux, it confirms that the latter actually resulted from O-3 production processes. This ozone production is here highlighted for the first time using O-3 fluxes measurements by the EC method. The chemical reactions possibly involved in O-3 production processes in this maritime pine forest have been discussed and different mechanisms are proposed, based on peroxy radicals chemistry or stress-induced BVOCs.
(Atmospheric Environment. vol. 197, n° 1352-2310, pp. 131-140, 24/04/2026)
UMR ISPA, INRA, Bordeaux Sciences Agro, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Nouveau modèle analytique pour une meilleure estimation des flux nets annuels en métaux dissous. Cas du cadmium dans l’estuaire de la Gironde
Nouveau modèle analytique pour une meilleure estimation des flux nets annuels en métaux dissous. Cas du cadmium dans l'estuaire de la Gironde New computation for a better estimation of the annual dissolved metal net fluxes. The case of the cadmium in the Gironde estuary
(Hydroécologie Appliquée, n° 1147-9213, 24/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IGE, IRD, Grenoble INP, INSU - CNRS, CNRS, UGA [2016-2019], Fédération OSUG
No-kill in restocking programs: Advances in non lethal detection of fluorochromes in marked juveniles, glass eel case study
Restocking is one of the alternatives measures that have been widely used as a measure of remediation of ichthyologic biodiversity loss. To assess restocking efficiency, mass-marking provided the discrimination of restocked fish compared to wild fish. The use of fluorochromes recorded in the calcified structures such as otoliths has been used extensively to detect marked fish. However, reading mark on otolith requires the sacrifice of the fish. European eel recruitment collapsed down to 1% of 1980s levels. Within European eel management plan, restocked glass eel are marked with Alizarine Red S (ARS 150 ppm). The aim of our study was to implement a nonlethal ARS mark detection method using modern techniques of microscopy, imaging and fluorimetry. Batches of ARS marked and unmarked glass eels within a restocking protocol were collected before they were translocated. For marked and unmarked glass eels, ARS detection mark was assayed i) on glass eel fins with a binocular microscope, ii) on anesthetized glass eels using a fluorescence reflectance imager and iii) on a piece of caudal glass eel fins using fluorimeter. Among the three alternative methods tested, non-lethal ARS detection using fluorimeter appeared to be most efficient, the easiest method and the cheapest method. Overall, the present results provided a widely applicable, easy and non-lethal method to researchers and managers for detecting endangered marked fish.
(24/04/2026)
UR EABX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CNRS
Adverse effects induced by chronic gamma irradiation in progeny of adult fish not affecting parental reproductive performance
Multigenerational studies became of great interest in ecotoxicology since the consequence of parental exposure on offspring generations has been established in situ or in laboratory conditions. This study mainly examined chronic effects of external Cs-137 gamma irradiation exposure at 4 dose rates (control, 0.5, 5 and 50 mGy h-1) on adult zebrafish (F0) exposed for 10 days and its progeny (F1) exposed for 4 days. The main investigated endpoints included parental reproductive performance, embryo-larval survival, DNA alterations and ROS production in F0 and F1. No effects on reproductive success, fecundity or egg fertilization rate were observed. However, drastic effects were observed on F1 at the highest dose rate, resulting in a mortality of 100%. The drastic effects were also observed when the progeny was not irradiated. We demonstrate that the sensitivity of the embryos was mainly due to parental irradiation. Moreover, these drastic effects induced by adult irradiation disappeared over time when 10 d- irradiated adults were placed in a non-irradiated condition. DNA alterations in larvae were observed for the three dose rates, with an increase of ROS production was also shown for the two lowest dose rates. This study improves our understanding of the consequences of multigenerational exposure conditions. Furthermore, it incentivizes us to take into account transmitted generational effects in ecological risk assessments.
(Environmental Toxicology and Chemistry. vol. 38, n° 0730-7268, pp. 2556-2567, 24/04/2026)
IRSN/PSE-ENV/SRTE/LECO, IRSN/PSE-ENV/SRTE, IRSN, IRSN/PSE-SANTE/SDOS/LMDN, IRSN/PSE-SANTE/SDOS, IRSN, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Holocene coastal changes along the Gironde estuary (SW France): new insights from the North Médoc peninsula beach/dune system
L’Amélie beach is located near the mouth of the Gironde estuary (south-western Atlantic coast of France). It has been greatly eroded by recent storms, especially in the winter of 2013-2014. Erosion of the dune front and beach has uncovered a set of estuarine and aeolian sediment deposits containing numerous archaeological remains. A campaign of topographic surveys was undertaken with DGPS and TLS equipment during the springs of 2014 and 2015 along the 2 km length of L’Amélie beach in order to reconstruct the elevation and stratigraphy of these deposits. Sedimentological analyses (grain size, micro-faunal) were performed to better constrain the depositional environment. Archaeological remains and several radiocarbon dates obtained from sediment samples collected in the field were used to propose a consistent chronological framework for this sedimentary sequence. Ten main lithofacies were distinguished from the lower part of the beach to the top of the dune. The base of the sedimentary sequence is composed of Pleistocene deposits dating from MIS 9 (unit 1a) to MIS 2 (unit 1b) (Bosq et al., 2019). The Holocene sedimentary infilling began around 5000 BC with an accumulation of coarse marine sands, which suggests the presence of a tidal inlet. On both sides of this tidal channel, archaeological remains dating from the early Neolithic period up to the Bronze Age testify to a human occupation of the coastal area. From ca. 5000 to ca. 3500 cal. a BP, a characteristic deposit of intertidal mudflats indicates the transformation of the tidal inlet into estuarine marshes protected by a coastal dune barrier. Between ca. 3500 and ca. 3000 cal. a BP, the dune barrier records a phase of erosion resulting in the exposure of the marsh to stronger hydrodynamic conditions. From ca. 2800 to 1650 cal. a BP, a second phase of estuarine sedimentation is recognized. This period is characterized by significant human occupation as indicated by the presence of numerous archaeological remains of the Iron Age and Gallo-Roman periods, associated with the exploitation of a saltwater-to-brackish environment. From 1650 to 1250 cal. a BP, the estuarine salt marsh is gradually overrun by northward migrating coastal-dune fields. After 1250 cal. a BP, the marsh is completely covered by aeolian sands. These results are consistent with previously published data and allow us to detail the local sequence of palaeogeographic changes of the north-Médoc peninsula. Using the ‘sea-level index points’ method (Hijma et al., 2015), the analysis of radiocarbon dated levels also provides new relative sea level records for this part of the French Atlantic coast. Finally, the phases of coastal dune activity/stability recognized along L’Amélie beach are synchronous with those in the wider Aquitaine coastal region, suggesting a regional driving factor. We propose that the shared sedimentary dynamics are the consequence of the onshore migration of intertidal and subtidal sand banks distributed at the mouth of the Gironde.
(Quaternaire. vol. 30, n° 1142-2904, pp. 47-75, 24/04/2026)
LETG, UNICAEN, NU, UA, EPHE, PSL, UBO EPE, UR2, CNRS, IGARUN, UN, UBM, CNRS, PRODIG (UMR_8586 / UMR_D_215 / UM_115), UP1, IRD, SU, CNRS, UPCité, PRODIG, UP1, IRD, EPHE, PSL, UP4, UPD7, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UPV / EHU, PACEA, UB, CNRS, LETG - Brest, LETG, UNICAEN, NU, UA, EPHE, PSL, UBO EPE, UR2, CNRS, IGARUN, UN, Inrap, LETG - Caen, LETG, UNICAEN, NU, UA, EPHE, PSL, UBO EPE, UR2, CNRS, IGARUN, UN
Climate Change and Risks for the Coastline: Scientific Contributions for a Sustainable and Just Adaptation
This contribution aims to be a summary and a presentation of knowledge from research conducted by the laboratories of Nouvelle-Aquitaine on the physical risks of coastal areas, their developments as a result of climate change and socio-economic and political dynamics at work with regard to the measures and strategies for adaptation. It is the result of collaboration between approximately 30 researchers from the following laboratories: BRGM, Criham (Université de Poitiers), EPOC (UMR Université de Bordeaux - CNRS), ETBX (Irstea), GREThA (UMR Université de Bordeaux - CNRS), LIENSs (UMR Université de La Rochelle - CNRS), ONF, SIAME (Université de Pau et des Pays de l'Adour).
(pp. 36, 24/04/2026)
UR ETBX, IRSTEA, BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LIENSs, INSU - CNRS, ULR, CNRS
A Late Quaternary record of highstand shedding from an isolated carbonate platform (Juan de Nova, southern Indian Ocean)
A 27 m core collected on the sea floor near Juan de Nova island at 1,909 m depth in the SW Indian Ocean preserves a high-resolution record of carbonate sediment export to the deep sea over the past 1 Myr. Core chronology was established using calcareous nannofossil biostratigraphy and benthic foraminiferal δ 18 O. Throughout the core, preserved highstand intervals (MIS 1, 5, 7, 9, 11, 13, 15, 23 and 25) are marked by an increase in the aragonite content within the sediment. Aragonite is likely sourced from the nearby Juan de Nova carbonate platform ca 10 km to the south, and is interpreted as resulting from flooding of the platform top. Platform inundation allows carbonate muds to be winnowed from their original shallow-water environment of deposition, suspended in the water column, and redeposited onto the proximal slopes and within the basin. Sharp increases in aragonite content at the beginning of each highstand interval can be used to estimate the approximate sea-level range when platform flooding occurred; results show that the depth of the platform top has likely changed little over the past 1 Myr due to balanced aggradation and subsidence. Previously hypothesized large-scale aragonite dissolution cycles are evidenced by a disproportionally low aragonite increase during MIS 11. This study provides a new, exceptionally long record of highstand shedding, expanding the known occurrences of the process to the southern Indian Ocean and supporting its importance as a globally significant depositional mechanism that impacts deep-sea stratigraphic records.
(Depositional Record. vol. 5, n° 2055-4877, pp. 540-557, 24/04/2026)
UCD, GM, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LGO, UBS, IFREMER, UBO EPE, CNRS
Effects of Improved 17 O Correction on Interlaboratory Agreement in Clumped Isotope Calibrations, Estimates of Mineral‐Specific Offsets, and Temperature Dependence of Acid Digestion Fractionation
The clumped isotopic composition of carbonate‐derived CO2 (denoted Δ47) is a function of carbonate formation temperature and in natural samples can act as a recorder of paleoclimate, burial, or diagenetic conditions. The absolute abundance of heavy isotopes in the universal standards VPDB and VSMOW (defined by four parameters: R13VPDB, R17VSMOW, R18VSMOW, and λ) impact calculated Δ47 values. Here, we investigate whether use of updated and more accurate values for these parameters can remove observed interlaboratory differences in the measured T‐Δ47 relationship. Using the updated parameters, we reprocess 14 published calibration data sets measured in 11 different laboratories, representing many mineralogies, bulk compositions, sample types, reaction temperatures, and sample preparation and analysis methods. Exploiting this large composite data set (n = 1,253 sample replicates), we investigate the possibility for a “universal” clumped isotope calibration. We find that applying updated parameters improves the T‐Δ47 relationship (reduces residuals) within most labs and improves overall agreement but does not eliminate all interlaboratory differences. We reaffirm earlier findings that different mineralogies do not require different calibration equations and that cleaning procedures, method of pressure baseline correction, and mass spectrometer type do not affect interlaboratory agreement. We also present new estimates of the temperature dependence of the acid digestion fractionation for Δ47 (Δ*25‐X), based on combining reprocessed data from four studies, and new theoretical equilibrium values to be used in calculation of the empirical transfer function. Overall, we have ruled out a number of possible causes of interlaboratory disagreement in the T‐Δ47 relationship, but many more remain to be investigated.
(Geochemistry, Geophysics, Geosystems. vol. 20, pp. 3495 - 3519, 24/04/2026)
PALEOCEAN, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, IUP, IPGP, INSU - CNRS, UPD7, UR, IPG Paris, CNRS, UF, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CALTECH
Environmental controls on surf zone injuries on high-energy beaches
The two primary causes of surf zone injuries (SZIs) worldwide, including fatal drowning and severe spinal injuries, are rip currents (rips) and shore-break waves. SZIs also result from surfing and bodyboarding activity. In this paper we address the primary environmental controls on SZIs along the high-energy meso-macro-tidal surf beach coast of southwestern France. A total of 2523 SZIs recorded by lifeguards over 186 sample days during the summers of 2007, 2009 and 2015 were combined with measured and/or hindcast weather, wave, tide, and beach morphology data. All SZIs occurred disproportionately on warm sunny days with low wind, likely because of increased beachgoer numbers and hazard exposure. Relationships were strongest for shore-break- and rip-related SZIs and weakest for surfingrelated SZIs, the latter being also unaffected by tidal stage or range. Therefore, the analysis focused on bathers. More shore-break-related SZIs occur during shore-normal incident waves with average to below-average wave height (significant wave height, Hs = 0.75-1.5 m) and around higher water levels and large tide ranges when waves break on the steepest section of the beach. In contrast, more rip-related drownings occur near neap low tide, coinciding with maximised channel rip flow activity, under shore-normal incident waves with Hs > 1.25 m and mean wave periods longer than 5 s. Addi- tional drowning incidents occurred at spring high tide, presumably due to small-scale swash rips. The composite wave and tide parameters proposed by Scott et al. (2014) are key controlling factors determining SZI occurrence, although the risk ranges are not necessarily transferable to all sites. Summer beach and surf zone morphology is interannually highly variable, which is critical to SZI patterns. The upper beach slope can vary from 0.06 to 0.18 between summers, resulting in low and high shore-break-related SZIs, respectively. Summers with coast-wide highly (weakly) developed rip channels also result in widespread (scarce) rip-related drowning incidents. With life risk defined in terms of the number of people exposed to life threatening hazards at a beach, the ability of morphodynamic models to simulate primary beach morphology characteristics a few weeks or months in advance is therefore of paramount importance for predicting the primary surf zone life risks along this coast.
(Natural Hazards and Earth System Sciences. vol. 19, n° 1561-8633, pp. 2183-2205, 24/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, SBMS, BRGM, UB, CHU Bordeaux, BPH, UB, INSERM
Microplastics FTIR characterisation and distribution in the water column and digestive tracts of small pelagic fish in the Gulf of Lions
(Marine Pollution Bulletin. vol. 142, n° 0025-326X, pp. 510--519, 24/04/2026)
UMR MARBEC, IRD, IFREMER, UM, CNRS, UM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS