Evaluation de la sensibilité des jeunes stades d'esturgeons européens aux polluants : chapitre V
Les objectifs de cette étude sont (i) d'évaluer la possibilité de créer artificiellement un sédiment dopé agissant de la même manière qu'un sédiment naturel chez l'esturgeon européen (ii) d'évaluer la sensibilité des jeunes stades d'esturgeon européen à différentes concentrations d'un mélange représentatif des polluants organiques et métalliques rencontrés dans l'environnement (iii) et enfin d'évaluer l'effet combiné de l'exposition aux polluants et à une augmentation de la température.
(pp. 59-70, 26/10/2026)
UR EABX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Peut-on améliorer l’élimination des micropolluants des eaux usées en optimisant le procédé à boues activées ?
Cette étude visait à améliorer l'élimination des micropolluants en modifiant les conditions de fonctionnement du procédé boues activées aération prolongée. Cette question a nécessité de mesurer les coefficients de sorption et les constantes de biodégradation (étude pilote), et de décrire la variabilité des concentrations dans les eaux usées brutes et les boues d'une installation vraie grandeur. 53 micropolluants ont été étudiés (11 métaux et 42 substances organiques). Au total, 8 campagnes d’échantillonnage de quelques jours ont été réalisées sur une durée d’un an, pour différentes conditions de fonctionnement de l'installation (concentration en boue, durée de présence d'oxygène, température). Les concentrations dans les eaux usées brutes ont varié de façon importante pour les substances organiques (50 à 100%), mais moindre pour les métaux (30%). Au cours d’une période de 24 heures, des concentrations deux fois plus élevées ont été mesurées dans la journée (6 h à 24 h), par comparaison aux concentrations mesurées la nuit pour plusieurs substances (ex. zinc, plomb, nonylphénol, propranolol, diclofénac). Nous avons démontré que la biodégradation explique l’élimination d’une dizaine de substances (ex. paracétamol, acébutolol, aténolol, ibuprofène, nonyl- et octyl-phénol). La sorption seule explique le transfert dans les boues des HAP lourds et des métaux. La sorption et biodégradation expliquent conjointement l’élimination d’une dizaine d’autres substances (ex. propranolol et quelques HAP). En complément, nous avons démontré que la biodégradation se déroule principalement en condition aérobie, surtout en présence simultanée de DCO et d’azote ammoniacal dans le bioréacteur, et avec une vitesse moindre en présence d’azote seul et très faible en phase endogène. Nous avons mesuré une faible dégradation des micropolluants une fois adsorbés sur les boues (
(TSM. Techniques Sciences Méthodes, n° 0299-7258, pp. 32-50, 26/10/2026)
UR MALY, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Levantine intermediate water hydrodynamic and bottom water ventilation in the northern Tyrrhenian Sea over the past 56,000 years: new insights from benthic foraminifers and ostracods
Foraminifera and ostracods have been quantitatively studied in core MD01-2472, from the upper continental slope (at water depth of 501 m), to evaluate their relationship with bottom water condition variability and decipher the control of the Levantine Intermediate Water (LIW) current on benthic faunas. The occurrence of reworked ostracod species (originating from the continental shelf) and, the presence of shallow water Elphidium/Ammonia benthic foraminifera are used to estimate the degree of along-slope transport at the core site. This has revealed two intervals of along-slope transport also associated with coarse-grained contourite deposits, deposited during the YD and HS2 episodes. Planktonic-benthic foraminiferal and ostracod assemblages reflect climate oscillations. Peaks of the polar planktonic Neogloboquadrina pachyderma (left-coiling S) may be used to identify Heinrich Events. Interstadials are marked by abundant ostracod species such as Paracypris sp., Argilloecia acuminata, and Cytheropteron alatum and the presence of benthic foraminifera like Bulimina marginata, Bulimina costata and Gyroidina altiformis. The B–A and Holocene are characterized by abundant warm water species of planktonic foraminifera and by the ostracod species Polycope sp. We hypothesize that there is relationship between LIW intensification during cold rapid climate events and benthic fauna assemblage variations due to changes in: 1) bottom water ventilation; and 2) the export of nutrients and/or sediment particles by bottom currents.
(Quaternary International, n° 1040-6182, pp. 395-313, 26/10/2026)
CEFREM, UPVD, INSU - CNRS, CNRS, UniPi, GEUS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GM, IFREMER
Selectivity of water obstacles on glass eel migration wave
Physical obstacles to upstream migration such as dams are a major impairment of natural colonisation and dispersion of migratory fish such as eels. Dams and obstacles increase fish energy expenditure, even when they are equipped with fish friendly devices. Besides, local accumulation of eels below dams increase the mortality associated with predation. Obstacles may also select on different traits of life history. While quantitative impact of dams is subjected to numerous studies, little is known about their intra-specific selectivity. Even the fishway efficiency analyses are scarcely hinting at their potential selective effect (Castro-Santos 2004; Noonan, Grant & Jackson 2012). The objective of this study was to pinpoint phenotypic traits predisposing glass eels to dams successful passage. In a preliminary approach we measured the transcription level of 15000 known eel genetic sequences in three main tissues (brain, liver and muscle) from wild individuals sampled on three successive river segments separated by dams. Interestingly, whereas no significant difference was observed in muscle and liver, segment-specific gene expression profiles were observed in brain. Surprisingly, the set of regulated genes was involved in synaptic plasticity, associated with animal cognition. In this study, by means of qPCR analysis of targeted genes, behavioral tests on experimental fishway and common garden experiment, the objective was to give insight into how genes related to learning and memory are associated with climbing behavior of fish.
(pp. 27, 26/10/2026)
UR EABX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EDF [E.D.F.]
Genetic and physiological responses of three freshwater diatoms to realistic diuron exposures
This study examined the effects of diuron on strains of three major freshwater diatom species, Eolimna minima, Nitzschia palea and Planothidium lanceolatum. These species are frequently recorded in the Morcille river, where diuron runs off during phytosanitary treatments of the vineyards around. Here, there were three diatom exposure groups for each species: 0, 1 and 10µg/L diuron during a fourteen-day laboratory assessment. Diuron water concentration, cell number, photosynthetic activity and gene expression were assessed at 6h, 2, 7 and 14 days after contamination. Diuron exposure altered photosynthetic activity in that the optimal quantum yield of photosystem II (PSII) decreased between 40 and 50% and, for Planothidium lanceolatum at 10µg/L, there was complete inhibition. Genetic responses indicated diuron effects on both photosystem II and mitochondrial metabolism in all three species at both diuron exposure levels. Thus, analysis of the expression of psaA, d1, cox1, nad5 and 12s could be an early biomarker to detect pesticide pollution. Overall, this study revealed differences in diuron sensitivity among the three species: Eolimna minima and Nitzschia palea appeared to be more tolerant than Planothidium lanceolatum. These results suggest that the development of molecular tools, and more precisely of biomarkers, will aid in early assessment of contamination and water quality.
(Environmental Science and Pollution Research. vol. 22, n° 0944-1344, pp. 4046-4055, 26/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR EABX, IRSTEA
Rôle des interactions plante-plante dans la réponse des forêts au changement climatique : l’exemple des forêts de chêne sessile et de hêtre dans les Pyrénées Occidentales
Les recherches concernant l’impact du changement climatique sur les forêts, telles que les modèles d’enveloppes climatiques et les modèles phénologiques, ignorent les interactions biotiques. Notre objectif est l’étude du rôle médiateur des interactions chêne-hêtre dans leur réponse au changement climatique dans les Pyrénées Occidentales. Des études préliminaires suggèrent que des différences importantes de sensibilité phénologique à la température entre ces espèces pourraient expliquer leur répartition altitudinale actuelle et l’évolution de leur balance compétitive avec le changement climatique. Nous présentons ici les résultats d’une expérimentation réalisée in situ et ayant pour but de quantifier les variations d’interactions entre des plantules de ces deux espèces et les arbres adultes le long d’un gradient altitudinal. Les résultats pour la survie des plantules montrent une augmentation importante de la compétition en altitude pour le chêne seulement. C’est le manque de chaleur à l’ombre du hêtre à haute altitude qui limite actuellement la longueur de la saison de végétation du chêne et sa progression en altitude. Le réchauffement climatique devrait diminuer la compétition subie par le chêne relativement au hêtre de par sa plus grande sensibilité phénologique à la température et ainsi exacerber les effets du changement climatique sur la migration altitudinale de ces deux espèces.
(Innovations Agronomiques. vol. 47, n° 1958-5853, pp. 97-108, 26/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UNINE, WSL, BioGeCo, INRA, UB
Toxicity of sediment-bound pollutants in the Seine estuary, France, using a Eurytemora affinis larval bioassay
Coastal urbanisation exposes surrounding estuarine environments to urban-related contaminants such as polycyclic aromatic hydrocarbons (PAHs), polychlorobiphenyls (PCBs) and pesticide mixtures. Hydrophobic contaminants can adsorb on estuarine sediments. They can subsequently be released on a massive scale in the aquatic environment due to artificial or natural phenomena (e.g. dredging, tides), thereby threatening living organisms. The contamination of sediment is a significant ecological issue in the Seine estuary, France. However, few relevant methods have been developed to assess sediment toxicity and its ecological impacts in a cost-effective way. In this context, we aimed to assess the toxicity of natural sediments from the Seine estuary on the development of the calanoid copepod Eurytemora affinis using a previously developed larval bioassay. This assay involves direct exposure of nauplii to elutriates of sediments for six days. Sediments were collected along the Seine estuary from six polluted sites and one reference site. Pollutants in this estuary included PAHs, PCBs and OCPs (organochlorine pesticides). Nauplius survival was significantly more affected by exposure to all contaminated sediment elutriates, than by exposure to sediment from Yville-sur-Seine (the reference site), whereas nauplius growth was significantly reduced after exposure to contaminated sediment elutriates from four of the six contaminated sites. We identified two distinct site clusters, one including both the sand-rich and the least polluted sediments (Oissel, Quillebeuf-sur-Seine, Caudebec-en-Caux) and the other including both the clay- and silt-rich, and the most polluted sediments (La Bouille, Poses, Pont de Normandie). As expected, survival was significantly more impacted after exposure to elutriates from the second cluster than from the first. This work enables (i) assessment of the toxicity of natural sediments in the Seine estuary and (ii) validation of the larval bioassay previously developed using sorbed sediment with model molecules.
(Ecotoxicology and Environmental Safety. vol. 113, n° 0147-6513, pp. 169-175, 26/10/2026)
SEBIO, INERIS, URCA, ULH, NU, URCA, CNRS, ESE, UP11, CNRS, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Étude de la contamination de la masse d’eau en pesticides, comparatif entre prélèvements ponctuels et échantillonnage passif – applications à des eaux naturelles et à des effluents de zones industrielles de la région bordelaise
Cent dix-neuf pesticides ont été recherchés dans des eaux naturelles de la Jalle d’Eysines, un cours d’eau aquitain, et dans des effluents de zones industrielles bordelaises, au cours de deux campagnes de prélèvement. Les molécules ont été quantifiées à partir de prélèvements moyennés sur 24 h. En parallèle, des échantillonneurs passifs de type POCIS (Polar Organic Chemicals Integrative Sampler) ont permis d’établir un suivi qualitatif. Les profils moléculaires au sein d’un même type de masse d’eaux sont identiques, mais diffèrent entre une eau naturelle et un effluent de zone industrielle. L’approche qualitative via les POCIS a permis de quantifier des molécules non détectées lors des prélèvements moyennés, tant pour les eaux de la Jalle d’Eysines que pour celles des zones industrielles. Les échantillonneurs passifs semblent donc prometteurs pour la caractérisation de masses d’eaux de différentes origines, en ce qui concerne les pesticides dont le log KOW est compris entre un et quatre. Il est cependant nécessaire de développer la démarche PRC (Performance Reference Compounds) afin d’y ajouter une visée quantitative.
(Revue des Sciences de l'Eau / Journal of Water Science. vol. 28, n° 0992-7158, pp. 223-228, 26/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UB
Leaf litter degradation in highly turbid transitional waters: preliminary results from litter-bag experiments in the Gironde Estuary
The rates of decomposition of oak (Quercus robur) leaves have been examined using litter bags in a very high turbidity macrotidal estuary, the Gironde Estuary (S.W. France). The first experiments show a marked decrease in the decomposition rate of oak leaves at the water-sediment interface (mud-contact: anoxic conditions, reduced physical fragmentation) in comparison to the water column. The results point out the impact of hydrodynamic conditions on leaf litter degradation in such fluvio-estuarine systems. Regarding the aquatic-terrestrial linkage, our observations suggest direct changes in leaf decomposition kinetics and then, a potential delay on the recycling and transport processes of coarse particulate organic matter, especially in a context of modification of the natural water flow, due to global and land use changes.
(Geodinamica Acta. vol. vol. 27, n° 0985-3111, pp. pp. 60-66, 26/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EDF R&D LNHE, EDF R&D, EDF [E.D.F.], LEFE, INEE-CNRS, CNRS, UT3, Comue de Toulouse, CNRS, Toulouse INP, Comue de Toulouse
Reconciling reconstructed and simulated features of the winter Pacific/North American pattern in the early 19th century
Reconstructions of past climate behavior often describe prominent anomalous periods that are not necessarily captured in climate simulations. Here, we illustrate the contrast between an interdecadal strong positive phase of the winter Pacific/North American pattern (PNA) in the early 19th century that is described by a PNA reconstruction based on tree rings from northwestern North America, and a slight tendency towards negative winter PNA anomalies during the same period in an ensemble of state-of-the-art coupled climate simulations. Additionally, a pseudo-proxy investigation with the same simulation ensemble allows for assessing the robustness of PNA reconstructions using solely geophysi-cal predictors from northwestern North America for the last millennium. The reconstructed early 19th-century positive PNA anomaly emerges as a potentially reliable feature, although the pseudo-reconstructions are subject to a number of sources of uncertainty and deficiencies highlighted especially at multidecadal and centennial timescales. The pseudo-reconstructions demonstrate that the early 19th-century discrepancy between reconstructed and simulated PNA does not stem from the reconstruction process. Instead, reconstructed and simulated features of the early 19th-century PNA can be reconciled by interpreting the reconstructed evolution during this time as an expression of internal climate variability, which is unlikely to be reproduced in its exact temporal occurrence by a small ensemble of climate simulations. However , firm attribution of the reconstructed PNA anomaly is hampered by known limitations and deficiencies of coupled climate models and uncertainties in the early 19th-century external forcing and background climate state.
(Climate of the Past. vol. 11, n° 1814-9324, pp. 939-958, 26/10/2026)
MPI-M, IUAV, GERICS, GKSS, UNIBE, PARVATI, LOCEAN, IPSL, ENS-PSL, UVSQ, UPMC, CEA, INSU - CNRS, X, CNES, CNRS, MNHN, IRD, UPMC, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS