At environmental doses, dietary methylmercury inhibits mitochondrial energy metabolism in skeletal muscles of the zebra fish (Danio rerio).
The neurotoxic compound methylmercury (MeHg) is a commonly encountered pollutant in the environment, and constitutes a hazard for human health through fish eating. To study the impact of MeHg on mitochondrial structure and function, we contaminated the model fish species Danio rerio with food containing 13 μg of MeHg per gram, an environmentally relevant dose. Mitochondria from contaminated zebrafish muscles presented structural abnormalities under electron microscopy observation. In permeabilized muscle fibers, we observed, a strong inhibition of both state 3 mitochondrial respiration and functionally isolated maximal cytochrome c oxidase (COX) activity after 49 days of MeHg exposure. However, the state 4 respiratory rate remained essentially unchanged. This suggested a defect at the level of ATP synthesis. Accordingly, we measured a dramatic decrease in the rate of ATP release by skinned muscle fibers using either pyruvate and malate or succinate as respiratory substrates. However, the amount and the assembly of the ATP synthase were identical in both control and contaminated muscle mitochondrial fractions. This suggests that MeHg induced a decoupling of mitochondrial oxidative phosphorylation in the skeletal muscle of zebrafish. Western blot analysis showed a 30% decrease of COX subunit IV levels, a 50% increase of ATP synthase subunit α, and a 40% increase of the succinate dehydrogenase Fe/S protein subunit in the contaminated muscles. This was confirmed by the analysis of gene expression levels, using RT-PCR. Our study provides a basis for further analysis of the deleterious effect of MeHg on fish health via mitochondrial impairment.
(International Journal of Biochemistry and Cell Biology. vol. 41, n° 1357-2725, pp. 791-799, 01/01/2009)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, U1211 INSERM/MRGM, UB, INSERM, IBGC, UB, CNRS
Treatment of topographic and bathymetric data acquired at the Truc-Vert Beach during the ECORS Field Experiment
The aim of this paper is to present the topographic and bathymetric surveys acquired during the international ECORS mission (March-April 2008) at Truc Vert Beach, SW of France. Topographic surveys have been done with an accuracy of about 2.5cm in the horizontal directions and 3cm for the elevation. Using both a GPS kinematics (by foot or implemented on a quad) and a theodolite, an area extending from the dune to the nearshore region was covered. In this paper, we present the methods developed in order to merge the different dataset. The acquisition and treatment of this large dataset was made possible thanks to the coordination of a large work force available on the field comprising numerous international institutions. From this work, together with the lower sample rate topographic data gathered over the last 10 years, Truc Vert Beach is the most documented beach of the French Coast.
(Journal of Coastal Research. vol. II, n° 0749-0208, pp. 1786-1790, 01/01/2009)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEGEM, UPVD, UPVD, SHOM, BRGM, LAB, UB, INSU - CNRS, CNRS
Etude expérimentale de la célérité des vagues en zone de surf
L'estimation de la célérité des vagues en zone de surf est une étape essentielle dans la modélisation de la circulation littorale. Nous présentons une étude de ce paramètre basée sur les données de la campagne de mesure internationale ECORS 2008. En particulier, nous analysons, pour des houles très energétiques, l'influence des non-linéarités et évaluons plusieurs modèles prédictifs de célérité. Enfin, nous discutons l'influence des pulsations très basse-fréquence de la circulation sur la célérité.
(24/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Holocene glacier and deep water dynamics, Adélie Land region, East Antarctica
This study presents a high-resolution multi-proxy investigation of sediment core MD03-2601 and documents major glacier oscillations and deep water activity during the Holocene in the Ade ´lie Land region, East Antarctica. A comparison with surface ocean conditions reveals synchronous changes of glaciers, sea ice and deep water formation at Milankovitch and sub-Milankovitch time scales. We report (1) a deglaciation of the Ade ´lie Land continental shelf from 11 to 8.5 cal ka BP, which occurred in two phases of effective glacier grounding-line retreat at 10.6 and 9 cal ka BP, associated with active deep water formation; (2) a rapid glacier and sea ice readvance centred around 7.7 cal ka BP; and (3) five rapid expansions of the glacier-sea ice systems, during the Mid to Late Holocene, associated to a long-term increase of deep water formation. At Milankovich time scales, we show that the precessionnal component of insolation at high and low latitudes explains the major trend of the glacier-sea ice-ocean system throughout the Holocene, in the Ade ´lie Land region. In addition, the orbitally-forced seasonality seems to control the coastal deep water formation via the sea ice-ocean coupling, which could lead to opposite patterns between north and south high latitudes during the Mid to Late Holocene. At sub-Milankovitch time scales, there are eight events of glacier-sea ice retreat and expansion that occurred during atmospheric cooling events over East Antarctica. Comparisons of our results with other peri-Antarctic records and model simulations from high southern latitudes may suggest that our interpretation on glacier-sea ice-ocean interactions and their Holocene evolutions reflect a more global Antarctic Holocene pattern.
(Quaternary Science Reviews. vol. 28, n° 0277-3791, pp. 1291 - 1303, 24/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, VU, FRE 2255
Impact of cadmium on aquatic bird Cairina moschata
The impact on palmiped Cairina moschata of two levels of dietary cadmium (Cd) contamination (C1: 1 mg kg-1 and C10: 10 mg kg-1) was investigated on liver gene expression by real-time PCR. Genes involved in mitochondrial metabolism, in antioxidant defences, detoxification and in DNA damage repair were studied. Metallothionein (MT) protein levels and Cd bioaccumulation were also investigated in liver, kidneys and muscle. Male ducks were subjected to three periods of exposure: 10, 20 and 40 days. Cd was mainly bioaccumulated in kidneys first and in liver. The concentrations in liver and kidneys appeared to reach a stable level at 20 days of contamination even if the concentrations in muscle still increased. Cd triggered the enhancement of mitochon-drial metabolism, the establishment of antioxidant defences (superoxide dismutase Mn and Cu/Zn; catalase) and of DNA repair from 20 days of contamination. Discrepancies were observed in liver between MT protein levels and MT gene up-regulation. MT gene expression appeared to be a late hour biomarker.
(BioMetals. vol. 22, n° 0966-0844, pp. 843-853, 24/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IPREM, UPPA, INC-CNRS, CNRS, UPPA
Comparaison d'estimateurs de régression non paramétriques : application en valvométrie,
(24/02/2026)
LMBA, UBS, UBO EPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Non parametric regression estimator: application in valvometry
(24/02/2026)
LMBA, UBS, UBO EPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Consequences of a recent flood event on the biogeochemistry of the Rhône Delta
(24/02/2026)
EDF R&D STEP, EDF R&D, EDF [E.D.F.], EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LPGN, UN, CNRS, IPGP, INSU - CNRS, UPD7, UR, IPG Paris, CNRS
Last glacial fire regime variability in western France inferred from microcharcoal preserved in core MD04-2845, Bay of Biscay
High resolution multiproxy analysis (microcharcoal, pollen, organic carbon, Neogloboquadrina pachyderma (s) , ice rafted debris) of the deep-sea record MD04-2845 (Bay of Biscay) provides new insights for understanding mechanisms of fire regime variability of the last glacial period in western France. Fire regime of western France closely follows Dansgaard–Oeschger climatic variability and presents the same pattern than that of southwestern Iberia, namely low fire regime associated with open vegetation during stadials including Heinrich events, and high fire regime associated with open forest during interstadials. This supports a regional climatic control on fire regime for western Europe through fuel availability for the last glacial period. Additionally, each of Heinrich events 6, 5 and 4 is characterised by three episodes of fire regime, with a high regime bracketed by lower fire regime episodes, related to vegetational succession and complex environmental condition changes.
(Quaternary Research. vol. 71, n° 0033-5894, pp. 385-396, 24/02/2026)
PACEA, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Ocean color measurements onboard a jet-ski : consistency for calval exercise of high-resolution satellite imagery?
(. vol. 7150, pp. Vol. 7150, Q1Q10, doi:10.1117/12.805382, 24/02/2026)
CRC, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS