Effect of dietary cadmium on lipid metabolism and storage of aquatic bird Carina moschata
In environment, birds often fast in connection with breeding, migration or drastic climatic conditions and need to mobilize lipid reserves during these periods. The impairment of lipid metabolism by cadmium (Cd; 1 mg kg(-1) added in diet) was investigated on palmiped Cairina moschata. Expression levels of genes involved in lipid metabolism, mitochondrial metabolism and detoxification were investigated in liver and muscle of ducks. Lipid content in muscle and liver were analysed and plasma triglycerides were quantified. After 20 days, ducks exposed to Cd displayed a lower body weight and lower lipid content in liver than controls. In muscle, the increase of lipid content was only significant for control ducks but not for exposed ducks. Exposed ducks appeared unable to sufficiently transport and store lipids into peripheral tissues. Cd impairs lipid metabolism by several ways. First, Cd triggered the down-regulation of fatty acids synthesis in liver even if the NADPH production and the mitochondrial metabolism are enhanced, suggesting a stronger energy needs. Secondly, the associated decrease of plasma triglycerides and lipoprotein lipase activity with Cd are consistent with impairment of lipids storage in peripheral tissues.
(Ecotoxicology, n° 0963-9292, pp. 163-170, 27/08/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UEPFG, INRA, IPREM, UPPA, INC-CNRS, CNRS
Modélisation physique de la morphodynamique d'une plage barrée tridimensionnelle
Des expériences dans un bassin de 30 m x 30 m ont été réalisées dans l'objectif de caractériser la dynamique d'un courant d'arrachement et les évolutions morphologiques associées. La plage de sable fin (diamètre médian 166 microns) couvrait la largeur du bassin (30 m en longshore ) pour un profil total de 20 m cross-shore . La formation de courants sagittaux a été forcée par une houle frontale (spectre de Jonswap) avec un déficit d'énergie au centre du bassin. Une séquence accrétive complète de plage intermédiaire à simple barre (selon classification de WRIGHT & SHORT, 1984) a été reproduite. La barre s'est progressivement tridimensionnalisée en forme de croissant puis s'est connectée au haut de plage avec la présence de deux chenaux profonds qui se sont ensuite comblés pour obtenir une plage à terrasse au bout de plusieurs dizaines d'heures. L'association des mesures hydrodynamiques et morphodynamiques montre que le comblement des chenaux est alimenté par le haut de plage.
(pp. 45, 27/08/2026)
LEGI, UJF, Grenoble INP, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UAG, INSU - CNRS, UM, CNRS, UQAR, LSEET, INSU - CNRS, UTLN, CNRS
Recovery potential of periphytic biofilm exposed to industrial contamination: field and experimental studies
This study was conducted in a context of impacted hydrosystem remediation in France. The Gironde fluvio-estuarine system has been subjected to polymetallic pollution (Cadmium and Zinc) for over a century, coming from an industrial site specialized in zinc ore treatment carrying contaminated wastes into a small tributary, located about 400 km upstream from the estuary. Since 2007 a major remediation phase has been initiated in the industrial site. This study aims to assess first biological modifications due to remediation procedure on periphytic diatoms biofilms, dominant primary producers in freshwaters. Therefore a yearly biomonitoring of the contamination was conducted in situ through 24 days colonizations cycles along the pollution gradient. The experiments were renewed every 48 days during a year. Glass slides were exposed in three stations located upstream the industrial site and one station dowstream the factory (Joany). After 24 days of colonization the glass slides were scraped to collect biofilm. Different tests were then performed: analyses of metal bioaccumulation, taxonomic investigations, numerations of diatom densities and biomass, and Chlorophyll a concentrations, completed by physicochemical measurements in water. Cadmium and zinc bioaccumulation concentrations were discriminating factors for biofilms from Joany, reaching maximum concentrations in dry weights (DW) of 861 ± 387 μg Cd.g-1 and 21 256 ± 5 701 μg Zn.g-1. Joany biofilms presented high densities too and low BDI values in comparison with the three other stations of colonization, located upstream the industrial site probably in relation with the important nutrients concentrations at this station due to urban wastewaters. Moreover, special attention was devoted to abnormal forms in the taxonomic investigations as it is established in the literature that contaminants promote abnormal forms frequencies. Maximum abnormality rate was observed in biofilms from Joany with 12, value significantly higher compared to biofilm from the 3 other stations below 5. Consequently, initial results show yet a persistence of metallic contamination in situ and high bioaccumulation in biofilms located dowstream industrial site. However, remediation is already perceivable in comparison with previous studies in which bioaccumulation (DW) reached 1809 ± 200 μg Cd.g-1 and 23 750 ± 2 469μg Zn.g-1 after 24 days of colonization at Joany in August 2004. Regarding the frequency of abnormal forms, it remains in the same order of magnitude of 10 to 20 at Joany according to this previous study . To understand in a detailed and integrated way whether the periphytic biofilm can initiate total or partial recovery, laboratory decontamination experiments free of environmental variations have thus been developped. The aim was to characterize the kinetics of biofilm recovery under controlled conditions after in situ and artificial expositions to Cd and Zn following the same analysis criteria than used for in situ experiments. Firsts results have shown a rapid decrease of metallic bioaccumulation with a return to control concentrations after 14 days under recovery conditions. This kind of results suggests the resurgence of sensitive species and the decrease of abnormal forms frequencies and put out diatom biofilm as an appropriate model to reveal effective recovery of polluted freshwater ecosystems.
(pp. 2, 27/08/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR REBX, CEMAGREF
Distribution of the organic matter in the channel-levees systems of the Congo mud-rich deep-sea fan (West Africa). Implication for deep offshore petroleum source rocks and global carbon cycle
The Corinth Rift is superimposed on the Hellenic nappe stack that formed at the expense of the Apulian continental crust above the subducting African slab. Extension started in the Pliocene and the major steep normal faults that control the geometry of the present-day rift were born very recently, some 600 kyr ago only. They root into a shallow-dipping zone of microseismicity recorded near the base of the upper crust. The significance of this seismogenic zone is debated. Considering the northward dip of the zone of microseismicity, the depth of microearthquakes and their focal mechanisms, we observe a strong similarity with the northern Cycladic detachments in terms of expected pressure, temperature conditions and kinematics. We herein show (1) that the formation of the Corinth Rift can be considered a part of a continuum of extension that started some 30–35 Ma in the Aegean and that was recently localised in a more restricted area, (2) that the present-day structure and kinematics of the Corinth Rift can be explained with a series of decollements relayed by steeper ramps that altogether formed a mechanically weak, crustal-scale detachment, and (3) that the deformation, fluid behaviour and metamorphic features seen in the northern Cycladic metamorphic core complexes can be good analogues of the processes at work below the Corinth Rift.
(Marine and Petroleum Geology. vol. 27, n° 0264-8172, pp. 995–1010, 27/08/2026)
iSTeP, UPMC, CNRS, ISTO, INSU - CNRS, UO, UT, NEOLAiA, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GM, IFREMER
Holocene Antarctic climate variability from ice and marine sediment cores: Insights on ocean–atmosphere interaction
Holocene climate variability in the southeast Atlantic sector of the Southern Ocean and Antarctic is assessed and quantified through integration of available marine sediment core and Antarctic ice core data. We use summer sea surface temperature (SSST) and sea ice presence (SIP) reconstructions from two marine sediment cores recovered north (50 S) and south (53.2 S) of the present day Antarctic Polar Front (APF), as well as an atmospheric temperature and sea ice proxy from the EPICA ice core from Dronning Maud Land (EDML). We find reasonably good agreement in the timing of climate evolution in the analyzed series. Almost all records show a gradual glacial-to-Holocene climate transition, interrupted by the Antarctic cold reversal around 13 000 cal yr BP, and early Holocene climatic optimum (HCO) at about 11 000 cal yr BP. During the early HCO, the seasonal ice cover retreats to south of 53 S; it then readvances in the course of the mid-to late Holocene. The maximum winter sea ice edge position during the recent 10 000 years varied mainly within 51-53 S, with sporadic growth to north of 50 S, a position similar to that during the last glacial. The onset of the Neoglacial period after ca 4000 yr BP is associated with a steepening of the SSST gradient between the marine core sites, strengthening of the westerlies and cooling in the inland ice sheet. The agreement in timing between elevated SSST during the early HCO and decreased deuterium excess in EDML and other ice cores from different locations in the East Antarctic suggests that the retreat of sea ice during the early HCO and weakening of the APF was a general feature of the East Antarctic climate during that time.
(Quaternary Science Reviews. vol. 29, n° 0277-3791, pp. 303-312, 27/08/2026)
UiT, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
THE EXTENSION OF ID11 FOR NANOSCALE AND HIERARCHICAL CHARACTERIZATION
Beamline ID11 at the ESRF has been recently upgraded by the complete redesign of the optics and by the extension of the beamline to 100 m in length. This has been coupled with the construction of a dedicated endstation for micro- and nano-focusing applications for diffraction and microscopy experiments in solid state chemistry, physics and materials science. Parallel detector schemes allow simultaneous characterization of samples over many length scales and throughout a multi-dimensional parameter space. We report the current ID11 scientific and technical status and the ongoing evolution.
(pp. 457-476, 27/08/2026)
ESRF, CEMHTI, UO, INC-CNRS, CNRS, LCND, LMA, AMU, ECM, CNRS, MATEIS, UCBL, INSA Lyon, INSA, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, DTU
Impact of solid waste disposal on nutrient dynamics in a sandy catchment
Groundwaters impacted by mature landfill leachate are generally enriched in ammonium. In order to assess the dynamics of ammonium exchanges between leachates and the water system inside a sandy permeable catchment we measured ammonium, nitrate and chloride concentrations in the stream and in sediment pore waters of the streambed of a landfill impacted aquifer. Geophysical investigation methods complemented the biogeochemical survey. The studied zone is a 23 km² catchment located in a coastal lagoon area sensitive to eutrophication risk. Ammonium concentrations in the river were up to 800 µmol l−1 during low water period in summer. Three surveys of the river chemistry showed a regular increase in ammonium, nitrate and chloride concentrations along a 1 km section of the watercourse, downstream the landfill, implying that the leachate plume exfiltrates along this section. Sediment cores collected within this section showed all an increase in ammonium concentrations with depth in pore waters as a consequence of the landfill leachate dispersion, as attested by a simultaneous increase in chloride concentrations. Nitrate enrichment in the river water was due to nitrification of ammonium at the interface between groundwater and streamwater. The apparent nitrification rate obtained was within values reported for turbid estuaries, although the river contained very little suspended particulate matter. Actually, pore water chemistry suggests that nitrification occurred for the most part in subsurface permeable sediments, rather than in stream water. The overall topographic, hydrological, geochemical, and geoelectrical data set permit to estimate the extension of the chloride and ammonium plume. The estimation of the apparent ammonium plume velocity is 23 m year−1 whereas the chloride plume velocity should be 50 m year−1. The river is the outlet of the impacted groundwaters. Considering that the input of ammonium from the landfill is balanced by the present day output via the river, the residence time of ammonium in the aquifer is between 7 and 18 years.
(Journal of Contaminant Hydrology. vol. 116, n° 0169-7722, pp. 1-15, 27/08/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, Ghymac, UB, EGID
Behavioral responses of Crassostrea gigas exposed to the harmful algae Alexandrium minutum
We describe the valve-activity behavior of oysters, Crassostrea gigas, exposed experimentally to the harmful alga Alexandrium minutum (≈ 3500 cell ml− 1) for 7-day periods under laboratory conditions. Our aim was to assess behavioral responses of oyster species during a mimicked bloom exposure. We determined different characteristic parameters of valve activity, such as daily valve opening duration, daily number of micro-closures, and valve-opening amplitude using a High Frequency-Non Invasive valvometer. In comparison with oysters exposed to non-toxic algae, T-Isochrysis or Heterocapsa triquetra, the valve activity of C. gigas is measurably different when exposed to toxic algae A. minutum. Surprisingly, daily valve-opening duration increased, as well as micro-closure activity, while valve-opening amplitude decreased. The response to A. minutum is fast, within 1 h after algae exposure. Following A. minutum exposure, recovery to control patterns was observed within 4-5 days. The behavioral alterations upon exposure to A. minutum can be thus used as a complementary physiological variable to other well-established physiological and biochemical measurements.
(Aquaculture. vol. 298, n° 0044-8486, pp. 338-345, 27/08/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEMAR, IRD, IFREMER, UBO EPE, CNRS
Flux dynamics of planktic foraminifers at a hemipelagic site of the inner Bay of Biscay (Northeast Atlantic margin)
(27/08/2026)
LPGN, UN, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LPO, IRD, IFREMER, UBO EPE, CNRS
Temporal variability of carbon recycling in coastal sediments influenced by rivers: assessing the impact of flood inputs in the Rhône River prodelta
River deltas are particularly important in the marine carbon cycle as they represent the transition between terrestrial and marine carbon: linked to major burial zones, they are reprocessing zones where large carbon fluxes can be min-eralized. In order to estimate this mineralization, sediment oxygen uptake rates were measured in continental shelf sediments and river prodelta over different seasons near the outlet of the Rhône River in the Mediterranean Sea. On a selected set of 10 stations in the river prodelta and nearby continental shelf, in situ diffusive oxygen uptake (DOU) and laboratory total oxygen uptake (TOU) measurements were performed in early spring and summer 2007 and late spring and winter 2008. In and ex situ DOU did not show any significant differences except for shallowest organic rich stations. Sediment DOU rates show highest values concentrated close to the river mouth (approx. 20 mmol O 2 m −2 d −1) and decrease offshore to values around 4.5 mmol O 2 m −2 d −1 with lowest gradients in a south west direction linked to the preferential transport of the finest riverine material. Core incubation TOU showed the same spatial pattern with an averaged TOU/DOU ratio of 1.2±0.4. Temporal variations of sediment DOU over different sampling periods, spring summer and late fall, were limited and benthic mineralization rates presented a stable spatial pattern. A flood of the Rhône River occurred in June 2008 and delivered up to 30 cm of new soft muddy deposit. Immediately after this flood, sediment DOU rates close to the river mouth dropped from around 15-20 mmol O 2 m −2 d −1 to values close to 10 mmol O 2 m −2 d −1 , in response to the deposi-tion near the river outlet of low reactivity organic matter associated to fine material. Six months later, the oxygen distribution had relaxed back to its initial stage: the initial spatial distribution was found again underlining the active microbial degradation rates involved and the role of further deposits. These results highlight the immediate response of the sediment oxygen system to flood deposit and the rapid relaxation of this system towards its initial state (6 months or less) potentially linked to further deposits of reactive material.
(Biogeosciences. vol. 7, n° 1726-4170, pp. 1187-1205, 27/08/2026)
LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, OCEANIS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, LEP, EEP, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IPGP - UMR_7154, INSU - CNRS, IGN, UR, IPG Paris, CNRS, UPCité, CEFREM, UPVD, INSU - CNRS, CNRS, LECOB, SU, CNRS, OOB, SU, CNRS