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, 09/04/2026)
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, 09/04/2026)
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, 09/04/2026)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CLDG, ULR
3D-fluorescence spectroscopic analysis of HPLC fractionated estuarine fulvic and humic acids
Six estuarine fulvic (FA) and humic acids (HA) were fractionated with reversed-phase high performance liquid chromatography in a water/acetonitrile gradient, with fluorescence detection. Differences between FA and HA chromatograms pointed to a higher incidence of hydrophobic components in the latter. Excitation-emission matrix fluorescence diagrams of most fractions were similar to those of the bulk samples indicating that, in spite of their distinct polarities, the complexity and main spectral characteristics of the materials persisted. A primary group of fluorophores, which are present in most of the fractions, seems to be at the origin of the fluorescence properties of both kinds of HS. A bathochromic shift of the bulk solutions spectra in relation to the fraction emissions was attributed to a greater proximity of these fluorophores, possibly due to the formation of aggregates. Generally, the results reinforced concepts that humic macromolecules consist of assemblages of structurally similar building blocks. \textcopyright 2006 Sociedade Brasileira de Qu\'imica.
(Journal of the Brazilian Chemical Society. vol. 17, n° 0103-5053, pp. 113--124, 09/04/2026)
UCS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Monitoring the maximum turbidity zone and detecting fine-scale turbidity features in the Gironde estuary using high spatial resolution satellite sensor (SPOT HRV, Landsat ETM+) data
This study concerns the quantification of suspended particulate matter in the highly turbid estuarine waters of the Gironde, France, from high spatial resolution remotely sensed data, SPOT (Satellite Pour l'Observation de la Terre) High Resolution Visible (HRV), Landsat Enhanced Thematic Mapper Plus (ETM+). The methodology is based on calibration relationships established between the remote sensing reflectance (R-rs) signal and suspended particulate matter concentration (SPM), from in situ optical measurements. These relationships are valid in the long term as R-rs ratios between near-infrared (NIR) and visible wavebands are relatively independent of the particle grain-size and mineralogy. Consequently, they can be applied to satellite images, even if no simultaneous in situ measurements are carried out concurrently with the satellite overpass. Selected satellite sensor data are corrected for atmospheric effects using radiative transfer code, then converted into surface water SPM concentrations according to the established calibration relationships. Resulting SPM maps are presented for different river flow and tidal conditions. These maps are used to locate the maximum turbidity zone and observe its tidal and seasonal movements. The high spatial resolution of SPOT HRV and Landsat ETM+ satellite sensor data also shows detailed turbidity features in the estuary, resulting from re-suspension phenomena over banks and turbulent currents.
(INTERNATIONAL JOURNAL OF REMOTE SENSING. vol. 27, pp. 2303-2321, 09/04/2026)
LOV, OOVM, UPMC, INSU - CNRS, CNRS, UPMC, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Spatial distribution of zooplankton size spectra on the French continental shelf of the Bay of Biscay during spring 2000 and 2001
During two cruises in springtime (18 March to 13 April 2000 and 27 March to 4 June 2001), the whole French continental shelf of the Bay of Biscay was sampled to obtain an overview on the zooplankton community size structure. A laboratory optical plankton counter (OPC-1L) was used to process plankton net tow samples and estimate abundance, biovolume, and general characteristics of size spectra. In a second step, biomass estimates were extrapolated from size by using a conversion factor. Both biomass and abundance estimates show spatial patterns with a clear coastal-open sea gradient for both years. The coastal area was characterized by the highest biomasses and abundances per volume. A first analysis of the zooplankton community size spectra was made by using the slope of the normalized biomass size spectrum. Different spatial patterns of zooplankton size spectra were highlighted for spring 2000 and 2001. The highest slopes were found for the coastal zone, showing a large ratio of small organisms, although this was less marked in the springtime 2000. Stations characterized by high proportions of large organisms were located in majority in the north of the bay and at the shelf break. A second analysis using the size probability distributions of organisms revealed a nearly permanent nonlinearity of probability distributions. This implied the community structure was not in an equilibrium state during spring and this nonlinearity could be locally related to dominant species dynamics.
(Journal of Geophysical Research. Oceans. vol. 111, n° 2169-9275, 09/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LOPB, INSU - CNRS, CNRS
Metallothionein gene expression and protein levels in triploid and diploid oysters Crassostrea gigas after exposure to cadmium and zinc.
Quantitative real-time polymerase chain reaction (PCR) was used to compare for the first time the differential expression of metallothionein (MT) isoform genes, together with biosynthesis of the total MT proteins, in the gills of triploid and diploid juvenile Pacific oyster Crassostrea gigas in response to cadmium (Cd) and zinc (Zn) exposure. Oysters were exposed to Cd (0.133 mM), Zn (15.3 mM), and Cd1Zn for 14 d. Results showed similar response capacities to metal exposures in the two populations. No significant difference was revealed in terms of MT gene expression, MT protein synthesis, and Cd accumulation. However, triploid oysters bioaccumulated Zn 30% less efficiently than diploid oysters. Among the three MT isoform genes, CgMT2 appeared to be more expressed than CgMT1, whereas CgMT3 appeared to be anecdotal (106 times lower than CgMT2). CgMT2 and CgMT1 gene expression levels were increased sevenfold in the presence of Cd, whereas Zn appeared to have no effect. A twofold increase in MT protein levels occurred in response to Cd exposure. Discrepancies between mRNA and protein levels suggest that in C. gigas MT are regulated at the transcriptional level, as well as at the translational level.
(Environmental Toxicology and Chemistry. vol. 25, n° 0730-7268, pp. 412-418, 09/04/2026)
LEESA, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEMAR, IRD, IFREMER, UBO EPE, CNRS
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, 09/04/2026)
PEPS, UCBL, INSU - CNRS, CNRS, LDO, INSU - CNRS, UBO EPE, CNRS
L'impact de la variabilité climatique rapide des OIS3-2 sur le peuplement de l'Europe.
Les changements climatiques qui ont affecté notre planète ont influencé les populations d'hominidés à de multiples échelles. Nombreuses sont les études qui se sont intéressées aux conséquences des changements climatiques à long terme sur les processus d'émergence, d'adaptation et d'extinction des espèces d'hominidés (Vrba, 1988 ; Wolde Gabriel et al. , 1994 ; Vrba et al. , 1995 ; Foley, 1994 ; Potts, 1996, 1998 ; Finlayson et al. , 2004 ; de Menocal, 1995, 2001 ; Behrensmeyer et al. , 1997 ; Bobe et al. , 2002). Moins nombreux sont les travaux qui se sont intéressés aux conséquences sur les populations humaines de changement climatiques de forte amplitude et de relativement brève durée (d'Errico et al. , 2001 ; d'Errico et Sánchez Goñi, 2003 ; Sánchez Goñi et d'Errico, 2004 ; Demars, 2003 ; Joris et al. , 2003 ; Jöris et Weniger, 2002). Nous savons, grâce aux avancées de la paléoclimatologie, que de tels changements climatiques se sont produits entre 40 0000 ans et 10 000 ans avant le présent (Heinrich, 1988 ; Dansgaard et al. , 1993 ; Bond et al. , 1993) et ont affecté de plein fouet le continent européen (Sánchez Goñi et al. , 2002). C'est la période au cours de laquelle on assiste dans cette région du globe à l'arrivée des hommes anatomiquement modernes, à l'extinction des néandertaliens et, par la suite, au développement des civilisations dites du Paléolithique supérieur. Comment évaluer l'impact de ces changements climatiques sur les populations paléolithiques ? Les recherches menées jusqu'à présent se sont souvent limitées à proposer un lien de cause à effet en s'appuyant sur la contemporanéité présumée entre un événement ou une série d'événements climatiques et des phénomènes biologiques (extinction ou émergence de nouvelles espèces, changement dans leur biogéographie) ou culturels (apparition ou déclin de systèmes techniques, modes d'organisation sociale, changements dans la distribution géographique de ces traits). Il est évident, cependant, que la contemporanéité entre un événement climatique et culturel/biologique ne constitue pas en elle-même la preuve que le premier soit la cause du second. D'où la nécessité de rendre explicite l'approche susceptible d'étayer et, dans une certaine mesure, de vérifier l'hypothèse climatique.
(pp. 265-282, 09/04/2026)
PACEA, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ArScAn, UP1, UP8, UPN, MCC, CNRS
Brachiopods, crustaceans, verte-brates, and charophytes from the Devonian Ly Hoa, Nam Can and Dong Tho formations of Central Vietnam
(Geodiversitas. vol. 28, n° 1280-9659, pp. 5-36, 09/04/2026)
LDO, INSU - CNRS, UBO EPE, CNRS, MNHN, UPMC, CNRS