Actions de diffusion de la culture scientifique et d'incitations aux sciences
The CSNSM contributes to the popularization of knowledge through various actions such as conferences for teenagers and students, redaction of books or papers for the general public, web sites, answers to Frequently Asked Questions.
(22/02/2026)
CSNSM, UP11, IN2P3, CNRS, DRECAM, CEA, LPN, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CSNSM, UP11, IN2P3, CNRS, CSNSM, UP11, IN2P3, CNRS, CSNSM, UP11, IN2P3, CNRS, CSNSM, UP11, IN2P3, CNRS, CSNSM, UP11, IN2P3, CNRS, IPNO, UP11, IN2P3, CNRS, IBCP, UCBL, CNRS, LHEEA, ECN, CNRS
Low-latitude "dusty events" vs. high-latitude "icy Heinrich events
It has been proposed that tropical events could have participated in the triggering of the classic, high-latitude, iceberg-discharge Heinrich events (HE). We explore low-latitude Heinrich events equivalents at high resolution, in a piston core recovered from the tropical northwestern African margin. They are characterized by an increase of total dust, lacustrine diatoms and fibrous lacustrine clay minerals. Thus, low-latitude events clearly reflect severe aridity events that occurred over Africa at the Saharan latitudes, probably induced by southward shifts of the Inter Tropical Convergence Zone. At a first approximation, it seems that there is more likely synchronicity between the high-latitude Heinrich Events (HEs) and low-latitude events (LLE), rather than asynchronous behaviours.
(Quaternary Research. vol. 68, n° 0033-5894, pp. 379-386, 22/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, PBDS, INSU - CNRS, CNRS, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France]
Clay mineral composition of river sediments in the Amazon Basin
(CATENA. vol. 71, n° 0341-8162, pp. 340-356, 22/02/2026)
LMTG, UT3, Comue de Toulouse, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UnB
Dansgaard-Oeschger climatic variability revealed by fire emissions in southwestern Iberia
Paleoenvironmental records in Europe describing paleofires extending back to the Last Interglacial have so far been unavailable. Here we present paleofire results from the combined petrographic and automated image analysis of microcharcoal particles preserved in marine core MD95-2042 retrieved off southwestern Iberia and covering the last climatic cycle. The variability of microcharcoal concentrations reveals that the variability of fire emissions is mainly imprinted by the 23 000 yrs precessional cycle. A focus on the Last Glacial Period further shows that paleofires follow the variability of Dansgaard-Oeschger oscillation and Heinrich events and, therefore, parallel the variability of atmospheric temperatures over Greenland detected in ice cores. There is no evidence for fire increase related to human activity. The variability of fire emission by-products for the Last Glacial Period is interpreted in terms of changes in biomass availability. Low fire activity is associated with periods of drought which saw the development of semi-desert vegetation that characterised stadial periods. Fire activity increased during wetter interstadials, related to the development of open Mediterranean forests with more woody fuel availability.
(Quaternary Science Reviews. vol. 26, n° 0277-3791, pp. 1369-1383, 22/02/2026)
PACEA, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CEREGE, IRD, INRA, AMU, CdF (institution), INSU - CNRS, CNRS, ISTO, INSU - CNRS, UO, CNRS, UCL-ASTR, UCL
Inocula from activated sludge for ready biodegradability testing : Homogenization by preconditioning
(Chemosphere. vol. 68, n° 0045-6535, pp. 1447-1454, 22/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEFE, INEE-CNRS, CNRS, UT3, Comue de Toulouse, CNRS, Toulouse INP, Comue de Toulouse
Sedimentary processes in the Thau Lagoon (France): From seasonal to century time scales
As a part of the MICROBENT programme, an investigation of the sedimentation framework was carried out at the water-sediment interface in the Thau Lagoon (French Mediterranean coast). Two main sites, C4 in the middle of the lagoon and C5 near oyster farms, were visited six times between December 2001 and May 2003. Interface sediments were studied using classical sedimentology parameters (radiography RX, grain size distribution) and analysis of selected radionuclides (234Th, 7Be, 210Pb, 226Ra). On a century time scale, excess 210Pb (210Pbxs) presents classical profiles with an upper mixed layer, followed by an exponential decrease of activities to undetectable levels below 20 - 30 cm. At the central site, C4, cores seem to register episodic changes in mean grain size, presenting recurrently peaks. The upper 10 cm of 210Pbxs profiles at site C5 exhibit a mixed layer associated with coarser sediments: this could be related to biological activity. Sedimentation rates derived from 210Pbxs varied from 0.15 cm y−1 at the edge of the basin, to 0.25 cm y−1 at the central site. On a seasonal time scale, 234Th and 7Be both show significant variations in activities and in penetration within the sediment. Bioturbation rates derived from both radionuclides agree well and range between 1-10 cm2 y−1 at site C4 and 1-31 cm2 y−1 at site C5. 234Th and 7Be fluxes at the water-sediment interface show too seasonal variations, more pronounced for site C5. This latter site presents especially a higher variability that is well marked with season, probably in relation with its position near oyster farms.
(Estuarine, Coastal and Shelf Science. vol. 72, n° 0272-7714, pp. 534-542, 22/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CEREGE, IRD, INRA, AMU, CdF (institution), INSU - CNRS, CNRS, LMGEM, CNRS, IPGP, INSU - CNRS, UPD7, UR, IPG Paris, CNRS
Comparative Evaluation of the Toxicity and Genotoxicity of Cadmium in amphibian larvae (Xenopus laevis and Pleurodeles waltl) Using the Comet Assay and tghe Micronucleus Test
The toxic and genotoxic potential of Cadmium (CdCl2) were evaluated by the micronucleus test (MNT) and comet assay (CA) using amphibian larvae (Xenopus laevis and Pleurodeles waltl). Acute toxicity results showed that Cd is toxic to Xenopus larvae exposed from 2 to 50 mg/L and to Pleurodeles from 5 to 50 mg/L, depending on the nature of the water (reconstituted water containing mineral salts or mineral water MW (Volvic®)). The MNT results obtained in MW showed that Cd (2 mg/L) is genotoxic to Xenopus, whereas it was not genotoxic to Pleurodeles at all concentrations tested. The CA established that the genotoxicity of Cd to Xenopus and Pleurodeles larvae depends on the concentration, the exposure times, and the comet parameters (Tail DNA, ETM, OTM, and TL). The CA and MNT results were compared for their ability to detect genotoxic effects, considering the concentrations of Cd applied and the exposure time. The CA showed Cd to be genotoxic from the first day of exposure. In amphibians, the CA appears to be a sensitive and suitable method for detecting genotoxicity such as that caused by Cd.
(Environmental Toxicology. vol. 22, n° 1520-4081, pp. 422-435, 22/02/2026)
LEFE, INEE-CNRS, CNRS, UT3, Comue de Toulouse, CNRS, Toulouse INP, Comue de Toulouse, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IRIT-SC, IRIT, UT Capitole, Comue de Toulouse, UT2J, Comue de Toulouse, UT3, Comue de Toulouse, CNRS, Toulouse INP, Comue de Toulouse, TMBI, UT2J, UT3, Toulouse INP, Comue de Toulouse, TESA, CBD, UT3, Comue de Toulouse, CNRS, CBI, UT3, Comue de Toulouse, CNRS, LSE-ENTPE, ENTPE, ENTPE, ENTPE
Parasite co-infection of two sympatric bivalves, the Manila clam (Ruditapes philippinarum) and the cockle (Cerastoderma edule) along a latitudinal gradient
Among the potential biotic factors affecting population dynamics, parasitism has received relatively little attention. The purpose of this study was to inventory marine bivalve parasites and to investigate relations between different parasite communities. Five intertidal stations along the French Atlantic shore were studied between Brittany and Arcachon Bay. Two bivalves (the edible cockle, Cerastoderma edule, and the Manila clam, Ruditapes philippinarum) were sampled and examined. The parasites included a bacterium (Vibrio tapetis), a protozoan (Perkinsus sp.), and digenetic trematode metacercariae (10 species). Perkinsus sp. prevalence and density in clams were higher than those measured in cockles (30 250 vs. 36 cells g−1 of gill wet weight, respectively) while digeneans were more common in cockles (46 metacercariae per cockle host vs. 1 per clam host). Distributions of digeneans and Perkinsus sp. were similar along the Atlantic shore. However, at each sampling station and at the individual scale, no correlation between Perkinsus sp. and digenean abundance was detected. These results suggest different ecological niches used by these two parasites within a community of bivalves but a similar response to environmental factors such as temperature and salinity. Vibrio tapetis was found at relatively high prevalence in all stations for both bivalve species (from 17% to 43% in cockles and from 23% to 50% in clams), but was associated with a low prevalence of Brown Ring Disease (BRD), a shell disease caused by this pathogen. No statistically significant relationship of these parasitic bacteria with trematodes and Perkinsus sp. was evidenced in the present study.
(Aquatic Living Resources. vol. 20, n° 0990-7440, pp. 33-42, 22/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEMAR, IRD, IFREMER, UBO EPE, CNRS
Impairment of lipid storage by cadmium in the European eel (Anguilla anguilla)
Because European silver eels (Anguilla anguilla) fast during their reproductive migration to the Sargasso Sea, the successful completion of their unusual life cycle depends on quantity of lipids stored beforehand. These lipids are mainly accumulated during the growth phase stage of the animals, called yellow eel, as triglycerides in muscle. They are then catabolized to provide sufficient energy to enable migration, gonad maturation and spawning. In the laboratory, we investigated the possible impact of cadmium on the lipid storage efficiency of yellow eels in order to evaluate the possible contribution of this pollutant to the reported decline of European eel populations. Eels were exposed to dissolved cadmium at nominal concentrations of 0 and 5 µg.L-1 for one month. Cd toxicity was then examined by studying the activity and expression level of several enzymes involved in liver lipolysis and lipogenesis and by determining lipid content in muscle. Contaminated eels showed a lower body weight growth with a lower efficiency of lipid storage compared to controls. Using two complementary approaches, genetic and enzymatic, it was possible to conclude that this impairment is mainly explained by an increased utilisation of triglycerides since cadmium contamination did not trigger a reduced fatty acid synthesis. These observations suggest an increased fat consumption in presence of cadmium, which could compromise successful reproduction.
(Aquatic Toxicology. vol. 81, n° 0166-445X, pp. 304-311, 22/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IBGC, UB, CNRS, UR EPBX, CEMAGREF
Silicic acid dynamics in the glacial sub-Antarctic: Implications for the silicic acid leakage hypothesis
The silicic acid leakage hypothesis (SALH) purports that changes in silicon and nitrogen depletion ratios in the glacial Antarctic created a large pool of unused silicic acid that was transported to lower latitudes in subantarctic mode water (SAMW) where it enhanced diatom productivity lowering atmospheric pCO 2. However, increased opal accumulation beneath the sub-Antarctic during glacial times implies significant consumption of silicic acid in subantarctic surface waters that may have significantly diminished or eliminated Si leakage. To test how nutrient dynamics in the sub-Antarctic affected the Si(OH) 4 content of SAMW during the last glacial period, we produced d 30 Si opal records for cores from the subantarctic and subtropical zones of the Indian Ocean spanning the last 50,000 years. Comparison with diatom-bound d 15 N records shows that subantarctic surface waters were enriched in Si relative to N during the last glaciation consistent with the SALH. The record from the subtropics does not show this enrichment in Si during the last glacial period suggesting that subantarctic surface waters were mainly incorporated into SAMW rather than being transported across the Subtropical Front. Isotope mass balance calculations were used to test for Si leakage from the sub-Antarctic. The results show that silicic acid concentration in SAMW would more than double during the last glaciation if upwelling and northward Ekman drift in the Antarctic were similar to the present-day circulation. Calculations that assume increased stratification in the glacial Antarctic eliminate Si leakage, but they do not produce the known increase in opal burial in the glacial sub-Antarctic. Reconciling the isotope data and opal burial records with a highly stratified Antarctic requires the addition of a large local source of silicic acid in the glacial sub-Antarctic that is inconsistent with present-day circulation and nutrient distributions. Including such a source in our calculations results in significant opal burial in the sub-Antarctic, but it does not enhance Si leakage over that occurring in the Holocene. Resolving past changes in the circulation of the Southern Ocean is clearly vital to future tests of the SALH.
(Global Biogeochemical Cycles. vol. 21, n° 0886-6236, pp. GB3015, 22/02/2026)
LEMAR, IRD, IFREMER, UBO EPE, CNRS, MSI, UC Santa Barbara, UC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS