Impact de la température et de l'hypoxie sur la physiologie et le comportement des larves d'esturgeon (Acipenser sturio)
European sturgeon (Acipenser sturio) is an anadromous fish which has been in sharp decline. Its last natural reproduction occurred in 1994. Because of global change, temperature have risen, frequency and severity of hypoxic events have increased. The goal of this paper is to determine the sensitivity of A. sturio early life stages to temperature and oxygen saturation. Embryo-larvae were exposed to combined temperature conditions, ranged from 12°C to 30°C, and dissolved oxygen, ranged from 30 to 90 % O2 saturation (% O2 sat). Acute and subacute effects were evaluated using embryonic and larval mortality, hatching success, malformation rate, routine metabolic rate (RMR) and swimming speed. Embryonic survival peaked at 20°C and no survival was recorded at 30°C. No hatching occurred at 50 % O2 sat or below. Malformation appeared to be minimum at 20°C, 90 % O2 sat. Maximum RMR were recorded at 20°C at 90 % O2 sat and 16°C at 70 % O2 sat. At 20°C, RMR at 70% O2 sat was lower than at 90% O2 sat. Swimming speed peaked at 16°C. A. sturio's temperature optimum is close to 20°C. Its upper tolerance limit is between 26 and 30°C and its lower tolerance limit is below 12°C. Oxygen depletion induce subacute effects at 70 % O2 sat and lethal effects at 50 % O2 sat. Current conditions in the basin are sustainable for A. sturio. Observing its sensitivity to oxygen depletion, a slight decrease would have large impact on European sturgeon survival capacity in the basin.
(pp. 70-77, 26/06/2026)
UR EABX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Procédés de traitement complémentaire intensifs pour améliorer l’élimination des micropolluants organiques présents dans les eaux usées
Bien que n’ayant pas été conçus dans ce but, les procédés conventionnels de traitement des eaux usées réalisent une élimination non négligeable des micropolluants par adsorption, biodégradation et/ou volatilisation. Néanmoins, certaines substances qualifiées de «réfractaires» sont partiellement ou pas du tout dégradées. Pour diminuer les niveaux de concentrations des micropolluants et contribuer à l’atteinte de valeurs compatibles avec le bon état du milieu récepteur, des traitements complémentaires intensifs peuvent être envisagés. Les procédés les plus efficaces actuellement pour éliminer ces substances réfractaires des eaux traitées sont des technologies avancées semblables à celles utilisées pour la production d’eau potable : ozonation, adsorption sur charbon actif en poudre ou en grain, filtration par membranes (en particulier osmose inverse). Néanmoins, il existe encore peu de retours sur l’efficacité de ces procédés à grande échelle sur des effluents de sortie de traitement secondaire et sur leurs coûts. Dans le cadre des projets AMPERES (ANR) et ARMISTIQ (ONEMA), quatre procédés de traitement intensif ont été évalués à pleine échelle ou à l’échelle industrielle dans plusieurs stations de traitement des eaux usées (STEU): ozonation, adsorption sur charbon actif, procédés d’oxydation avancée et procédés membranaires (ultrafiltration, osmose inverse). Tous ces procédés ont permis d’obtenir de bonnes performances pour l’élimination des micropolluants. Le charbon actif, par exemple, permet d’éliminer à plus de 70% la plupart des médicaments quantifiés ainsi que les pesticides urées et triazines. Les coûts de ces traitements ont été calculés pour des scénarios d’élimination des micropolluants identiques à pleine échelle. L’ozone est la technologie la moins coûteuse parmi celles qui ont été étudiées, en particulier pour les STEU de taille moyenne à grande.
(pp. 27, 26/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR MALY, IRSTEA, IRSTEA
Impact du métolachlore sur la physiologie et le comportement de la diatomée dulçaquicole Gomphonema gracile
Les micro-algues jouent un rôle fondamental dans les écosystèmes aquatiques : elles sont à la base des réseaux trophiques et ce en raison de leur statut de producteurs primaires. Au sein des milieux aquatiques, elles peuvent ainsi être directement impactées par des molécules de type herbicide provenant des écosystèmes terrestres et retrouvées dans le milieu par des phénomènes de ruissellement, drainage, infiltration et lessivage des sols. Cependant, les descripteurs actuels (croissance, fluorescence chlorophyllienne) s’avèrent parfois peu sensibles pour détecter les impacts toxiques de molécules dont la cible n’est pas le photosystème. Dans ce contexte, cette étude a pour but de quantifier l’impact de l’herbicide métolachlore (inhibiteur des élongases) sur une espèce de diatomée dulçaquicole Gomphonema gracile Ehrenberg, mise en culture et isolée du milieu d’étude, la Leyre (principal tributaire du bassin d’Arcachon). Cet herbicide est le contaminant majoritaire du bassin versant (en termes de fréquence de quantification et de concentration). Sa toxicité est évaluée sur des paramètres physiologiques (croissance, photosynthèse, concentration en ATP) et comportementaux (mobilité). Alors que les descripteurs classiques (par exemple l’activité photosynthétique) ne permettent pas de mettre en évidence d’impact toxique du métolachlore, et ce quelle que soit la concentration testée, les descripteurs de mobilité (pourcentage de cellules mobiles, vitesse de déplacement) démontrent des impacts toxiques, pour des concentrations environnementales. Nos résultats soulignent l’importance de l’utilisation de descripteurs d’effet diversifiés, et démontrent le potentiel prometteur d’indicateurs comportementaux pour la mise en évidence de contaminations toxiques.
(pp. 22, 26/06/2026)
UR EABX, IRSTEA, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Chronic dietary exposure to pyrolytic and petrogenic mixtures of PAHs causes physiological disruption in zebrafish - part I: survival and growth
The release of polycyclic aromatic hydrocarbons (PAHs) into the environment has increased very substantially over the last decades leading to high concentrations in sediments of contaminated areas. To evaluate the consequences of long-term chronic exposure to PAHs, zebrafish were exposed, from their first meal at 5 days post fertilisation until they became reproducing adults, to diets spiked with three PAH fractions at three environmentally relevant concentrations with the medium concentration being in the range of 4.6–6.7 μg g−1 for total quantified PAHs including the 16 US-EPA indicator PAHs and alkylated derivatives. The fractions used were representative of PAHs of pyrolytic (PY) origin or of two different oils of differing compositions, a heavy fuel (HO) and a light crude oil (LO). Fish growth was inhibited by all PAH fractions and the effects were sex specific: as determined with 9-month-old adults, exposure to the highest PY inhibited growth of females; exposure to the highest HO and LO inhibited growth of males; also, the highest HO dramatically reduced survival. Morphological analysis indicated a disruption of jaw growth in larvae and malformations in adults. Intestinal and pancreatic enzyme activities were abnormal in 2-month-old exposed fish. These effects may contribute to poor growth. Finally, our results indicate that PAH mixtures of different compositions, representative of situations encountered in the wild, can promote lethal and sublethal effects which are likely to be detrimental for fish recruitment.
(Environmental Science and Pollution Research. vol. 21, n° 0944-1344, pp. 13804-13817, 26/06/2026)
BE, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEMAR, IRD, IFREMER, UBO EPE, CNRS, LIENSs, INSU - CNRS, ULR, CNRS, LRHLR, HGS, IFREMER, LPGP, INRA, Biosit : Biologie - Santé - Innovation Technologique
Chronic dietary exposure of zebrafish to PAH mixtures results in carcinogenic but not genotoxic effects
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants that can be present at high levels as mixtures in polluted aquatic environments. Many PAHs are potent mutagens and several are well-known carcinogens. Despite numerous studies on individual compounds, little is known about the toxicity of PAHs mixtures that are encountered in environmental situations. In the presentwork, zebrafish were continuously fed from 5 days post-fertilisation to 14 months post-fertilisation (mpf) with a diet spiked with fractions of either pyrolytic (PY), petrogenic light oil (LO), or petrogenic heavy oil (HO) origin at three concentrations. A decrease in survival was identified after 3 mpf in fish fed with the highest concentration of HO or LO, but not for PY. All PAH fractions caused preneoplastic and neoplastic disorders in longterm-exposed animals. Target tissues were almost exclusively of epithelial origin, with the bile duct epithelium being themost susceptible to chronic exposure to all PAH fractions, and with germ cells being the second most responsive cells. Significantly higher incidences of neoplasms were observed with increasing PAH concentration and exposure duration. Themost severe carcinogenic effects were induced by dietary exposure to HO compared to exposure to LO or PY (45, 30 and 7 %, respectively, after 9 to 10 months of exposure to an intermediate concentration of PAHs). In contrast, earliest carcinogenic effects were detected as soon as 3 mpf after exposure to LO, including the lowest concentration, or to PY. PAHbioactivation and genotoxicity in blood was assessed by ethoxyresorufin-Odeethylase activity quantification and comet and micronuclei assays, respectively, but none of these were positive. Chronic dietary exposure of zebrafish to PAH mixtures results in carcinogenotoxic events that impair survival and physiology of exposed fish.
(Environmental Science and Pollution Research. vol. 21, n° 0944-1344, pp. 13833-13849, 26/06/2026)
PAnTher, Oniris VetAgroBio, INRAE, UNAM, Oniris VetAgroBio, LIENSs, INSU - CNRS, ULR, CNRS, BE, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LPGP, INRA, Biosit : Biologie - Santé - Innovation Technologique
Retreat history of the East Antarctic Ice Sheet since the Last Glacial Maximum
The East Antarctic Ice Sheet (EAIS) is the largest continental ice mass on Earth, and documenting its evolution since the Last Glacial Maximum (LGM) is important for understanding its present-day and future behaviour. As part of a community effort, we review geological evidence from East Antarctica that constrains the ice sheet history throughout this period (∼30,000 years ago to present). This includes terrestrial cosmogenic nuclide dates from previously glaciated regions, 14C chronologies from glacial and post-glacial deposits onshore and on the continental shelf, and ice sheet thickness changes inferred from ice cores and continental-scale ice sheet models. We also include new 14C dates from the George V Land – Terre Adélie Coast shelf. We show that the EAIS advanced to the continental shelf margin in some parts of East Antarctica, and that the ice sheet characteristically thickened by 300–400 m near the present-day coastline at these sites. This advance was associated with the formation of low-gradient ice streams that grounded at depths of >1 km below sea level on the inner continental shelf. The Lambert/Amery system thickened by a greater amount (800 m) near its present-day grounding zone, but did not advance beyond the inner continental shelf. At other sites in coastal East Antarctica (e.g. Bunger Hills, Larsemann Hills), very little change in the ice sheet margin occurred at the LGM, perhaps because ice streams accommodated any excess ice build up, leaving adjacent, ice-free areas relatively unaffected. Evidence from nunataks indicates that the amount of ice sheet thickening diminished inland at the LGM, an observation supported by ice cores, which suggest that interior ice sheet domes were ∼100 m lower than present at this time. Ice sheet recession may have started ∼18,000 years ago in the Lambert/Amery glacial system, and by ∼14,000 years ago in Mac.Robertson Land. These early pulses of deglaciation may have been responses to abrupt sea-level rise events such as Meltwater Pulse 1a, destabilising the margins of the ice sheet. It is unlikely, however, that East Antarctica contributed more than ∼1 m of eustatic sea-level equivalent to post-glacial meltwater pulses. The majority of ice sheet recession occurred after Meltwater Pulse 1a, between ∼12,000 and ∼6000 years ago, during a period when the adjacent ocean warmed significantly. Large tracts of East Antarctica remain poorly studied, and further work is required to develop a robust understanding of the LGM ice sheet expansion, and its subsequent contraction. Further work will also allow the contribution of the EAIS to post-glacial sea-level rise, and present-day estimates of glacio-isostatic adjustment to be refined.
(Quaternary Science Reviews. vol. 100, n° 0277-3791, pp. 10-30, 26/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BTP, LOCEAN, IPSL, ENS-PSL, UVSQ, UPMC, CEA, INSU - CNRS, X, CNES, CNRS, MNHN, IRD, UPMC, INSU - CNRS, CNRS
Importance, but not intensity of plant interactions relates to species diversity under the interplay of stress and disturbance
The lack of clarity on how the intensity and importance of plant interactions change under the co-occurrence of stress and disturbance strongly impedes assessing the relative importance of plant interactions for species diversity. We addressed this issue in subalpine grasslands of the French Pyrenees. A natural soil moisture gradient further experimentally stretched at both ends was used and a mowing disturbance treatment was applied at each position along the soil moisture gradient. Changes in intensity and importance of plant interactions were assessed by a neighbour removal experiment using four target ecotypes. A structural equation modelling approach was used to assess the relative impact of stress, disturbance, the intensity and importance of plant interactions on diversity at both the neighbourhood and community scales. Without mowing, changes in intensity and importance of plant interactions only diverged in the dry part of the soil moisture gradient. The intensity of plant interactions linearly shifted from competition to facilitation with increasing stress, while the importance followed a hump-shaped relationship. Species diversity components were tightly related to the importance of plant interactions only, both the neighbourhood and community scales. Mowing disturbance strongly reduced the importance of facilitation along the soil moisture gradient, and suppressed the relationship between the importance of plant interactions and diversity components. Together, our results highlight that 1) the importance is the best predictor of variations in species diversity in this subalpine herbaceous system, and 2) that fine-scale processes such as plant interactions can affect the entire plant communities. Finally, our results suggest that high level of constraints due to co-occurring stress and disturbance can inhibit the effects of plant interactions on species diversity, highlighting their potential role in regulating diversity and the maintenance/extinction of plant communities.
(Oikos. vol. 123, n° 0030-1299, pp. 777–785, 26/06/2026)
UB, BioGeCo, INRA, UB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Evidence for a three-phase sequence during Heinrich Stadial 4 using a multiproxy approach based on Greenland ice core records
Glacial climate was characterised by two types of abrupt events. Greenland ice cores record Dansgaard-Oeschger events, marked by abrupt warming in-between cold, stadial phases. Six of these stadials appear related to major Heinrich events (HEs), identified from ice-rafted debris (IRD) and large excursions in carbon-and oxygen-stable isotopic ratios in North Atlantic deep sea sediments, documenting major ice sheet collapse events. This finding has led to the paradigm that glacial cold events are induced by the response of the Atlantic Meridional Overturning Circulation to such massive freshwater inputs, supported by sensitivity studies conducted with climate models of various complexities. These models also simulate synchronous Green-land temperature and lower-latitude hydrological changes. To investigate the sequence of events between climate changes at low latitudes and in Greenland, we provide here the first 17 O-excess record from a Greenland ice core during Dansgaard-Oeschger events 7 to 13, encompassing H4 and H5. Combined with other ice core proxy records, our new 17 O-excess data set demonstrates that stadials are generally characterised by low 17 O-excess levels compared to interstadials. This can be interpreted as synchronous change of high-latitude temperature and lower-latitude hydrological cycle (relative humidity at the oceanic source of evaporation or change in the water mass trajectory/recharge) and/or an influence of local temperature on 17 O-excess through kinetic effect at snow formation. As an exception from this general pattern, stadial 9 consists of three phases, characterised first by Greenland cooling during 550 ± 60 years (as shown by markers of Greenland temperature δ 18 O and δ 15 N), followed by a specific lower-latitude fingerprint as identified from several proxy records (abrupt decrease in 17 O-excess, increase in CO 2 and methane mixing ratio, heavier δD-CH 4 and δ 18 O atm), lasting 740 ± 60 years, itself ending approximately 390 ± 50 years prior to abrupt Greenland warming. We hypothesise that this lower-latitude signal may be the fingerprint of Heinrich event 4 in Greenland ice cores. The proposed decoupling between stable cold Greenland temperature and low-latitude climate variability identified for sta-dial 9 provides new targets for benchmarking climate model simulations and testing mechanisms associated with millen-nial variability.
(Climate of the Past. vol. 10, n° 1814-9324, pp. 2115-2133, 26/06/2026)
LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, NBI, UCPH, GLACCIOS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, PALEOCEAN, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA
Bages-Sigean and Canet-St Nazaire lagoons (France): physico-chemical characteristics and contaminant concentrations (Cu, Cd, PCBs and PBDEs) as environmental quality of water and sediment
Environmental characteristics in water and sediments of two contrasted coastal Mediterranean lagoons, Bages-Sigean and Canet-St Nazaire, were measured over a three season survey. The urban pollution (treatment plant discharges) is very important in Canet-St Nazaire lagoon reflecting untreated sewages, while in Bages-Sigean, the northern part appears more impacted due to larger anthropogenic inputs. Dissolved Cd concentrations are on the whole similar in both lagoons, whereas Cu concentrations are by far higher in lagoon Canet-St Nazaire. Cu concentrations appear to be highly dependent on dissolved organic carbon whereas salinity seems to control Cd variations. Concerning the sediments, the confined northern part of lagoon Bages-Sigean shows organic carbon and total nitrogen enrichment whereas lipid concentrations are much higher in the Canet-St Nazaire lagoon. Cu complexation seems to be strongly related to organic matter as evidenced by the two significant positive relationships, on one hand between Cu and organic carbon, and on the other hand, between Cu and lipids. On the contrary, Cd concentrations appear to be mainly controlled by carbonates. PCBs and PBDEs were detected only in sediments and show relatively low concentrations compared to similar lagoon environments. Regarding the sediment quality guidelines, Cd, Cu and PCBs in both lagoons did not exceed any Probable Effect Concentration (PEC).
(Environmental Science and Pollution Research. vol. 21, n° 0944-1344, pp. 3005-3020, 26/06/2026)
IMAGES-Espace DEV, IRD, UPVD, AU, UR, UM, UG, UA, CEFREM, UPVD, INSU - CNRS, CNRS, CEFREM, UPVD, INSU - CNRS, CNRS, LMTG, UT3, Comue de Toulouse, CNRS, CGS, INSU - CNRS, CNRS, METIS, UPMC, EPHE, PSL, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Evaluation du devenir des micropolluants dans les procédés de traitement des boues biologiques (compostage, lits de séchage plantés de roseaux, digestion anaérobie) et de séchage (thermique et solaire) - (ARMISTIQ – Action D)
L’objectif de l’action D du projet ARMISTIQ était d’évaluer le devenir des micropolluants à travers les procédés de traitement des boues. Des campagnes d’échantillonnage ont été faites dans neuf installations de traitement des boues : un sécheur thermique basse température, un sécheur thermique haute température, un sécheur solaire, une digestion anaérobie suivie d’un compostage accéléré en tunnels, une unité de compostage en casiers ventilés, une unité de compostage rustique en andains et deux lits de séchage plantés de roseaux. 79 micropolluants ont été analysés dans les échantillons de boue brute, de boue traitée, de déchets verts, de refus de criblage, de compost et de condensats. Ils ont été choisis en fonction de leur occurrence dans les boues de stations de traitement des eaux usées domestiques, de leurs propriétés physico-chimiques, de leur toxicité et de la réglementation mais également en fonction de leurs limites de quantification et de la disponibilité d’une technique analytique dans la matrice boue. Un protocole d’échantillonnage spécifique a été développé afin de suivre un « lot » de boue à travers le procédé de traitement. Des bilans matière ont été effectués afin de calculer des rendements d’élimination pour les 9 installations de traitement des boues en suivant des règles de calcul spécifiques permettant d’obtenir des données robustes malgré les incertitudes liées à l’échantillonnage et à l’analyse.Certains micropolluants sont partiellement éliminés grâce aux procédés de traitement des boues : Le séchage solaire semble permettre une réduction de la concentration en hormones dans la boue, même si les concentrations en hormones étaient très faibles dans les boues d’entrée. Le séchage thermique haute température semble permettre une réduction partielle des HAP dans les boues, mais le rendement a fortement varié selon la concentration en HAP en entrée. Les HAP ont également été partiellement éliminés par le lit de séchage planté de roseaux fonctionnant à 14 semaines de repos. Les procédés de traitement des boues évalués ont tous permis une dégradation des nonylphénols mono et diéthoxylates (en nonylphénols). Une unité de compostage et un lit de séchage planté de roseaux (faible rythme d’alimentation-repos) ont permis d’éliminer partiellement les nonylphénols. Le séchage thermique (haute température) a eu un effet d’élimination sur les octylphénols. Le compostage en casiers et le lit de séchage planté de roseaux (faible rythme d’alimentation-repos) ont été efficaces sur DEHP, galaxolide, tonalide, di-butylphtalate et triclosan. Par contre, le bisphenol A s’est accumulé dans les boues pour le compostage. Le lit de séchage planté de roseaux fonctionnant sous 2 semaines d’alimentation et 14 semaines de repos a montré de meilleures efficacités d’élimination que celui fonctionnant sous 2 jours d’alimentation et 14 jours de repos. Aucun des procédés étudiés n’a permis d’éliminer les métaux, excepté le mercure, partiellement volatilisé dans le sécheur à haute température. Aucun des procédés de traitement des boues étudiés dans ce projet n’a permis une élimination de la charge globale en micropolluants dans les boues. Certains micropolluants s’accumulent dans les boues traitées, principalement car ce sont des produits de dégradation d’autres composés, partiellement éliminés pendant le traitement.
(pp. 82, 26/06/2026)
UR MALY, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS