Etude intégrée de l’effet des apports amont et locaux sur le fonctionnement de la Garonne estuarienne (ETIAGE) : Addendum année 4 Avril 2013 - Mars 2014
Le programme ETIAGE a été mis en place avec pour objectif de répondre aux questions suivantes : que représentent les apports des effluents de la Communauté Urbaine de Bordeaux (CUB) par rapport à ceux venant de l’amont en termes de charge organique et de micro-polluants ? Quels rôles sur le devenir des effluents jouent la présence du bouchon vaseux et la stagnation résiduelle des eaux (déplacement net entre mouvement de flot et de jusant) au niveau de l’estuaire fluvial amont en période d’étiage estival ? Réciproquement, à quels moments et jusqu’où s’étend l’impact de ces effluents sur la qualité des eaux de la Garonne estuarienne ? Quelles incidences des effluents sur le comportement des populations biologiques en place ou migratoires dans la Garonne estuarienne ? Quelle tendance évolutive va connaître l’oxygénation des eaux ? Quel sera l’impact sur le comportement des micro-polluants et des populations biologiques ? Quelles recommandations de gestion pourraient être préconisées à partir de la synthèse des pressions exercées sur les eaux de la Garonne estuarienne ? Le programme est divisé en 5 axes, dont les bilans de travail sont présentés axe par axe.
(pp. 152, 26/06/2026)
UR EABX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Post-failure Processes on the Continental Slope of the Central Nile Deep-Sea Fan: Interactions Between Fluid Seepage, Sediment Deformation and Sediment-Wave Construction,
Voluminous mass-transport deposits (MTD) have been identified on seismic profiles across the central Nile Deep-Sea Fan (NDSF). The youngest MTDs are buried under 30-100 m of well-stratified slope deposits that, in water depths of 1,800-2,600 m, are characterized by undulating reflectors correlated with slope-parallel seabed ridges and troughs. Seabed imagery shows that, in the western part of the central NDSF, short, arcuate undulations are associated with fluid venting (carbonate pavements, gas flares), while to the east, long, linear undulations have erosional furrows on their downslope flanks and fluid seeps are less common. Sub-bottom profiles suggest that the western undulations correspond to rotated fault-blocks above the buried MTDs, while those in the east are sediment waves generated by gravity flows. We suggest that fluids coming from dewatering of MTDs and/or from deeper layers generate overpressures along the boundary between MTDs and overlying fine-grained sediment, resulting in a slow downslope movement of the sediment cover and formation of tilted blocks separated by faults. Fluids can migrate to the seafloor, leading to the construction of carbonate pavements. Where the sediment cover stabilizes, sediment deposition by gravity flows may continue building sediment waves. These results suggest that complex processes may follow the emplacement of large MTDs, significantly impacting continental-slope evolution.
(Advances in Natural and Technological Hazards Research. vol. 37, pp. 117-127, 26/06/2026)
GEOAZUR 7329, INSU - CNRS, UniCA, CNRS, IRD [Occitanie], IRD, UniCA, OGS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Qualitative and quantitative reconstructions of surface water characteristics and recent hydrographical changes in the Trondheimsfjord, central Norway
In the present study we investigated dinocyst assemblages in the Trondheimsfjord over the last 25 to 50 yr from three well-dated multi-cores (210 Pb and 137 Cs) retrieved along the fjord axis. The downcore distribution of the dinocysts is discussed in view of changes in key hydro-graphic parameters of the surface waters (sea-surface temperatures (SSTs), sea-surface salinities (SSSs), and river discharges) monitored in the fjord. We examine the impact of the North Atlantic Oscillation pattern and of waste water supply from the local industry and agriculture on the fjord ecological state and thus dinocyst species diversity. Our results show that dinocyst production and diversity in the fjord is not evidently affected by human-induced eutrophication. Instead the assemblages appear to be mainly controlled by the NAO-related changes in nutrient availability and the physico-chemical characteristics of the surface mixed layer. Still, discharges of major rivers have been modulated since 1985 by the implementation of hydropower plants, which certainly influences the amounts of nutrients supplied to the fjord. The impact, however, is variable according to the local geographical setting, and barely differentiated from natural changes in river run off. We ultimately test the use of the modern analogue technique (MAT) for the reconstruction of winter and summer SSTs and SSSs and annual primary productivity (PP) in this particular fjord setting. The reconstructed data are compared with time series of summer and winter SSTs and SSSs measured at 10 m water depth, as well as with mean annual PPs along the Norwegian coast and in Scandinavian fjords. The reconstructions are generally in good agreement with the instrumental measurements and observations from other fjords. Major deviations can be attributed to peculiarities in the assemblages linked to the particular fjord setting and the related hydrological structure.
(Climate of the Past. vol. 10, n° 1814-9324, pp. 305-323, 26/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
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
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
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
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
Unexpected biotic resilience on the Japanese seafloor caused by the 2011 Tohoku-Oki tsunami
On March 11th, 2011 the Mw 9.0 2011 Tohoku-Oki earthquake resulted in a tsunami which caused major devastation in coastal areas. Along the Japanese NE coast, tsunami waves reached maximum run-ups of 40 m, and travelled kilometers inland. Whereas devastation was clearly visible on land, underwater impact is much more difficult to assess. Here, we report unexpected results obtained during a research cruise targeting the seafloor off Shimokita (NE Japan), shortly (five months) after the disaster. The geography of the studied area is characterized by smooth coastline and a gradually descending shelf slope. Although high-energy tsunami waves caused major sediment reworking in shallow-water environments, investigated shelf ecosystems were characterized by surprisingly high benthic diversity and showed no evidence of mass mortality. Conversely, just beyond the shelf break, the benthic ecosystem was dominated by a low-diversity, opportunistic fauna indicating ongoing colonization of massive sand-bed deposits.
(Scientific Reports. vol. 4, n° 2045-2322, pp. 7517, 26/06/2026)
JAMSTEC, LPG, UA, UN UFR ST, UN, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CEFREM, UPVD, INSU - CNRS, CNRS, CEREGE, IRD, INRA, AMU, CdF (institution), INSU - CNRS, CNRS, NIOZ, BIAF, UA
Etude intégrée de l’effet des apports amont et locaux sur le fonctionnement de la Garonne estuarienne (ETIAGE) : Axe 5 Synthèses des pressions et des impacts caractérisant les eaux de la Garonne estuarienne. Recommandations de gestion
Le programme ETIAGE a été mis en place avec pour objectif de répondre aux questions suivantes : que représentent les apports des effluents de la Communauté Urbaine de Bordeaux (CUB) par rapport à ceux venant de l’amont en termes de charge organique et de micro-polluants ? Quels rôles sur le devenir des effluents jouent la présence du bouchon vaseux et la stagnation résiduelle des eaux (déplacement net entre mouvement de flot et de jusant) au niveau de l’estuaire fluvial amont en période d’étiage estival ? Réciproquement, à quels moments et jusqu’où s’étend l’impact de ces effluents sur la qualité des eaux de la Garonne estuarienne ? Quelles incidences des effluents sur le comportement des populations biologiques en place ou migratoires dans la Garonne estuarienne ? Quelle tendance évolutive va connaître l’oxygénation des eaux ? Quel sera l’impact sur le comportement des micro-polluants et des populations biologiques ? Quelles recommandations de gestion pourraient être préconisées à partir de la synthèse des pressions exercées sur les eaux de la Garonne estuarienne ? Une présentation très synthétique des résultats, obtenus sur les quatre années du programme, est donnée : axe Caractérisation et rôle respectif des apports organiques amont et locaux sur l’oxygénation des eaux de la Garonne estuarienne ; axe 2 Caractérisation et flux des contaminants organiques (classiques et émergents) dans les eaux de la Garonne estuarienne ; axe 3 Apports métalliques de la CUB à la Gironde ; axe 4 actions 1 et 3 Inventaire et caractérisation saisonnière de la macrofaune présente (poissons et crustacés) dans la masse d’eau sous influence directe des apports de l’agglomération bordelaise; étude des effets des périodes hypoxiques sur les fonctionnements biologiques ; axe 4 action 2 : Approche de l’impact des conditions physico-chimiques affectant la masse d’eau estuarienne garonnaise sur les cortèges biologiques ; axe 4 action 4 Evaluation des niveaux de contamination et effets toxicologiques sur les composantes biologiques exposées dans la masse d’eau estuarienne garonnaise.
(pp. 21, 26/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CNRS, UB, IRSTEA, UR EABX, IRSTEA
Influence des hydrophytes envahissants sur la biogéochimie des lacs peu profonds
Influence des hydrophytes envahissants sur la biogéochimie des lacs peu profonds (influence sur les dynamiques de l'oxygène et du carbone dissous, dont le méthane).
(pp. 14, 26/06/2026)
UR EABX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS