ENSO and interdecadal climate variability over the last century documented by geochemical records of two coral cores from the South West Pacific
The south west Pacific is affected by climatic phenomena such as ENSO (El Niño Southern Oscillation) or the PDO (Pacific Decadal Oscillation). Near-monthly resolution calibrations of Sr/Ca, U/Ca and d18Oc were made on corals taken from New Caledonia and Wallis Island. These geochemical variations could be linked to SST (sea surface temperature) and SSS (sea surface salinity) variations over the last two decades, itselves dependent on ENSO occurrences. On the other hand, near-half-yearly resolution over the last century smoothes seasonal and interannual climate signals, but emphasizes low frequency climate variability.
(Advances in Geosciences. vol. 6, n° 1680-7340, pp. 27, 09/01/2006)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, PALEOTROPIQUE
cDNA cloning and gene expression of ribosomal S9 protein gene in the mollusk Corbicula fluminea: A new potential biomarker of metal contamination up-regulated by cadmium and repressed by zinc
Biological indicators can be used to assess polluted sites, but their success depends on their specificity. The aim of the present study was to identify a specific cadmium biomarker of the freshwater bivalve Corbicula fluminea. Differential display technique was used to identify new molecular indicators for cadmium exposure. Gene expression of C. fluminea transplanted into a cadmium- and zinc-contaminated river was compared to gene expression of bivalves from a reference site. One differentially expressed band was identified, and the entire cDNA sequence coding for the ribosomal protein S9 (rpS9) was cloned. The rpS9 gene expression was studied by real-time reverse transcription-polymerase chain reaction. After controlled cadmium (15 microg/L) and/or zinc (1 mg/L) laboratory contaminations of the bivalves, this gene was shown to be up-regulated by cadmium and down-regulated by zinc. A 48-d transplantation of animals into a polymetallic field contamination in the Lot river basin (Midi-Pyrénées region, France) showed that rpS9 gene regulation was correlated with the fluctuating cadmium and zinc water contents. To our knowledge, the existence of a gene that is up-regulated by cadmium and repressed by zinc is demonstrated here for the first time.
(Environmental Toxicology and Chemistry. vol. 25, n° 0730-7268, pp. 527, 01/01/2006)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Modélisation du courant sagittal induit par les vagues au-dessus des systèmes barre/baïne de la côte aquitaine (France)
Modelling of a rip current induced by waves over a ridge and runnel system on the Aquitanian Coast, France. The spectral wave driver SWAN is coupled with the time- and depth-averaged (2DH) coastal area model MORPHODYN. This coupled model is used to simulate the rip current induced by breaking waves over ridge and runnel systems on the French Aquitanian Coast. Simulations lead to a description of the rip current characteristics and the physical mechanisms leading to its formation. The rip current is controlled by the local bathymetry, the tide level and offshore wave conditions. The presence of this rip current is favoured by shore-normal incidence and long-period swells. During low-energy conditions, the maximum rip current velocity occurs at midtide. For higher energy conditions, the maximum rip velocity sweeps to high tide. The residual forcing notion enables to explain and to highlight this tidal modulation and the rip current formation mechanisms
(Comptes Rendus. Géoscience. vol. 338, n° 1631-0713, pp. 711-717, 01/01/2006)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Modélisation du festonnage des barres sableuses d'avant-côte : application à la côte aquitaine, France
Modeling of crescentic pattern development of nearshore bars: Aquitanian Coast, France. Nearshore crescentic bars play key role in nearshore morphodynamics. These bars are observed all along the Aquitanian Coast, with a mean wavelength of about 700 m. A non-linear stability analysis is undertaken to simulate the development of crescentic patterns. Results show that self-organization mechanism can lead alone to the development of these alongshore rhythmic features. Simulated wavelengths are in agreement with observations on the Aquitanian Coast.
(Comptes Rendus. Géoscience. vol. 338, n° 1631-0713, pp. 795-801, 01/01/2006)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IMB, UB, Bordeaux INP, CNRS
A surface complexation model for cadmium and lead adsorption onto diatom surface
This work is devoted to the physico-chemical study of cadmium and lead interaction with diatom–water interfaces for two marine planktonic (Thalassiosira weissflogii = TW, Skeletonema costatum = SC) and two freshwater periphytic species (Achnanthidium minutissimum = AMIN, Navicula minima = NMIN) by combining adsorption measurements with surface complexation modeling. Reversible adsorption experiments were performed at 20 °C after 3 h of exposure as a function of pH, metal concentration in solution, and ionic strength. While the shape of pH-dependent adsorption edge is similar among all four diatom species, the constant-pH adsorption isotherm and maximal binding capacities differ. These observations allowed us to construct a surface complexation model for cadmium and lead binding by diatom surfaces that postulates the constant capacitance of the electric double layer and considers Cd and Pb complexation with mainly carboxylic and, partially, silanol groups. Parameters of this model are in agreement with previous acid–base titration results and allow quantitative reproduction of all adsorption experiments.
(Journal of Geochemical Exploration. vol. 88, n° 0375-6742, pp. 110-113, 01/01/2006)
LMTG, UT3, Comue de Toulouse, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
DNA adduct measurements in zebra mussels, Dreissena polymorpha Pallas. Potential use for genotoxicant biomonitoring of fresh water ecosystems
(Aquatic Toxicology. vol. 79, n° 0166-445X, pp. 55-64, 27/05/2026)
ANTICIPE, UNICAEN, NU, CHU Caen Normandie, NU, UNICANCER/CRLC, NU, INSERM, UNICANCER/CRLC, NU, UB, UB, GRECAN, UNICAEN, NU, UNICANCER/CRLC, NU, ABTE, UNICAEN, NU, UNIROUEN, NU, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Le tuf de Caours (Somme, France) : mise en évidence d'une séquence eemienne et d'un site paléolithique associé
Les nouvelles investigations menées sur les tufs du bassin de la Somme dans le cadre du programme SITEP (CNRS) ont permis de mettre en évidence une formation tufacée reposant sur une nappe alluviale en position de très basse terrasse à Caours (Scardon). La séquence de tufs est sé-parée de la nappe alluviale périglaciaire sous-jacente par des limons fluviatiles calcaires se terminant par un petit sol de marais coiffé par un liseré de tourbe compactée. La formation tufacée proprement dite comporte essentiellement des faciès palustres à nombreux restes végétaux encroûtés en place et des concrétions travertineuses de type stromatolithes. En direction de la vallée actuelle l'ensemble passe rapidement à des faciès nettement fluviatiles à oncolithes structurés en grandes lentilles à stratifications obliques. La séquence de tuf ainsi que les limons fluviatiles ont livré une abondante faune malacologique qui a permis de décrire une évolution climatique contemporaine des phases initiales d'un interglaciaire, suivi d'un optimum climatique, puis d'une phase de réouverture du milieu exprimant le déclin des conditions tempérées. La base du tuf comporte plusieurs horizons organiques qui ont livré des restes de grands mammifères et de rongeurs contemporains de l'optimum interglaciaire déterminé par les assemblages malacologiques. Dans ces horizons, plusieurs niveaux du Paléolithique moyen ont été découverts en place, en association avec des restes de grande faune interglaciaire fortement fracturés par l'action de l'homme et présentant des traces de découpe. Compte tenu de sa position dans le sys-tème de la Somme, des datations par U/Th obtenues sur le tuf (moyenne : ± 120 ka BP) et des conclusions des études bioclimatiques, la séquence de Caours représente le premier témoin de l'interglaciaire Eemien en contexte fluviatile dans le bassin de la Somme. Enfin, les niveaux archéologiques découverts à Caours constituent un exemple unique d'occupation humaine contemporaine du dernier interglaciaire dans la France septentrionale.
(Quaternaire. vol. 17, n° 1142-2904, pp. 281--320, 27/05/2026)
LGP, UP1, UPEC UP12, CNRS, Evo-Eco-Paléo (EEP), CNRS, Inrap, PEQENO, CNRS, GEOTOP, EPM, UdeM, UQAT, UQAR, UQAM, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, OCEANIS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, HQMC, MNHN, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IRAMAT, UTBM, UO, UBM, CNRS, GEOTRAC, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, MNHN, CNRS
Support of Subtidal Tracer Studies to Quantify the Complex Morphodynamics of a River Outlet: the Bevano, NE Italy.
Evolution of tidal inlets or river outlets has been widely described all over the world. However, most conceptual models are based on the long term perspective and field measurements to confirm these evolution schemes are scarce. The objective of the present study is to quantify the processes occurring at a small river outlet, the Bevano, during fair weather conditions. Subtidal fluorescent sand tracer method involving a new detection tool were used in the inlet and along the adjacent coast to assess sediment transport and bypassing processes. At the river mouth, sediment fluxes confirm an efficient bypass of sand through the inlet's channel. However, this sediment transport is combined with migration processes of the channel (40min 2 months), and yields a self-alimentation of both updrift and downdrift coasts. As it has already been observed at small tidal inlets, migration of the Bevano river mouth results from the erosion of the downdrift coast, and readjustment of the cross-section by the longshore transport on the updrift coast. The detection device used for subtidal tracing has given encouraging results and will be improved in order to work in more dynamic environments.
(Journal of Coastal Research. vol. SI39, n° 0749-0208, pp. 602-606, 27/05/2026)
UniFE, BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Contributions respectives des courants et de la houle dans la mobilité sédimentaire d'une plate-forme interne estuarienne. Exemple : le seuil interinsulaire, au large du pertuis d'Antioche, France. Respective contributions of currentsnext term and swell to the sediment mobility in an internal estuarine platform. Example of the inner shelf seaward of the ‘pertuis Charentais', France
Respective contributions of currents and swell to the sediment mobility in an internal estuarine platform. Example of the inner shelf seaward of the ‘pertuis Charentais', France. This paper investigates the relative influence of waves, wind-induced current and tidal current on the sediment mobility of a macro-tidal environment belonging to the inner shelf seaward of the ‘pertuis Charentais' (France). This study, mainly based on three-week hydrodynamic in-situ measurements, shows that, for a water depth of 23 m, the swell (rather than wind waves) orbital velocity is large enough to initiate the motion of medium sands that are then transported by currents. Estimations show that medium sand of 0.2 mm is transported during 92% of the measurements, whereas coarse sand and gravel move sporadically, during storm, synchronously with spring tides. Further more, bedload fluxes appear strongly larger when waves are taken into account (370 times larger for 0.2-mm sands)
(Comptes Rendus. Géoscience. vol. 338, n° 1631-0713, pp. 718-726, 27/05/2026)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CLDG, ULR
SYNCARID CRUSTACEANS FROM THE MONTCEAU LAGERSTÄTTE (UPPER CARBONIFEROUS; FRANCE)
Key aspects of the morphology, autecology, systematics and taphonomy of the crustacean syncarids from the Montceau Lagerstätte (Upper Carboniferous, Stephanian B; France) are presented. Palaeocaris secretanae is the most abundant faunal element of the Montceau biota and shows striking morphological similarities with Palaeocaris typus from the Mazon Creek Lagersta¨tte (Westphalian D; Illinois, USA). Palaeocaris secretanae was a shrimp-like animal with a short head (no head shield), large mandibles, 14 trunk segments (the first one being reduced) and a fan-like caudal termination. Both the body and the appendage design indicate abilities for crawling on the substratum (slender endopods) and for escape reaction (uropodal fan, pleonal flexibility), although swimming activities may have been reduced (trunk appendages with small flap-like exopods). Details of the appendages involved in feeding, e.g. mandibles and maxillipeds, indicate poor ability for predation but point to an omnivorous detritus feeding mode. Poorly developed respiratory organs (small cylindrical epipods) suggest a relatively low level of locomotory activity. The field of vision may have been large and panoramic (stalked eyes). Rows of pores on 12 trunk segments are interpreted as possible sensory organs used for current detection. Females were brooding eggs (clusters of eggs preserved along anteroventral trunk). Microprobe analysis indicates that siderite is the major component of the nodules. Four events played a key-role in the three-dimensional preservation of syncarids: (1) rapid burial, (2) minimal decomposition, (3) phosphatic mineralization shortly after the animal's death and (4) nodule formation around the carcass. Palaeocaris secretanae is morphologically close to Recent syncarids such Anaspides tasmaniae (freshwater streams, Australia) in its general body plan and detailed anatomy, e.g. mouth parts, indicating morphological stasis in syncarids over more than 200 million years.
(Paleontology. vol. 49, pp. 647-672, 27/05/2026)
PEPS, UCBL, INSU - CNRS, CNRS, LDO, INSU - CNRS, UBO EPE, CNRS