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, 11/04/2026)
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, 11/04/2026)
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, 11/04/2026)
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, 11/04/2026)
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)
(11/04/2026)
LPGN, UN, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LPO, IRD, IFREMER, UBO EPE, CNRS
Experimental study of cadmium interaction with periphytic biofilms
This study addresses the interaction of Cd with natural biofilms of periphytic diatoms grown during different seasons in metal-contaminated and metal-non-contaminated streams, along a tributary of the Lot River, France. Specifically, it aims to test whether the biofilms from contaminated sites have developed a protective mechanism due to high Cd exposure. Towards this goal, reversible adsorption experiments on untreated biofilms were performed in 0.01 M NaNO3 with a pH ranging from 2 to 8, Cd concentration from 0.5 to 10,000 μg/L and exposure time from 1 to 24 h. Two types of experiments, pH-dependent adsorption edge and constant-pH Langmuirian-type isotherms were conducted. Results were adequately modeled using a Linear Programming Model. It was found that the adsorption capacities of natural biofilm consortia with respect to Cd do not depend on season and are not directly linked to the growth environment. The biofilms grown in non-contaminated (4.6 ppb Cd in solid) and contaminated (570 ppb Cd in solid) settings exhibit similar adsorption capacities in the Cd concentration range in solution of 10010,000 μg/L but quite different capacities at low Cd concentration (0.5100 μg/L); unexpectedly, the non-contaminated biofilm adsorbs approximately 10 times more Cd than the contaminated one. It is therefore possible that the strong low-abundant ligands (for example, phosphoryl or sulfhydryls) are already metal-saturated on surfaces of biofilm grown in the contaminated site whereas these sites are still available for metal adsorption in samples grown in non-contaminated sites.
(Applied Geochemistry. vol. 25, n° 0883-2927, pp. 418-427, 11/04/2026)
CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR REBX, CEMAGREF, VAST
Fish under influence: a macroecological analysis of relations between fish species richness and environmental gradients among European tidal estuaries
Estuarine fish assemblages are subject to a great environmental variability that largely depends on both upstream fluvial and downstream marine influences. From this ecohydrological view, our study introduces a macroecological approach aiming to identify the main environmental factors that structure fish assemblages among European tidal estuaries. The present paper focuses on the influence of large scale environmental gradients on estuarine fish species richness. The environment of 135 North-eastern Atlantic estuaries from Portugal to Scotland was characterized by various descriptors especially related to hydromorphology. Major environmental trends among estuaries were underlined using multivariate techniques and cluster analyses applied to abiotic data. In particular, an integrative system size covariate was derived from a principal component analysis. Factors explaining patterns of species richness at different scales from local habitat to regional features were highlighted. Based on generalised linear models, the estuarine system size, and more particularly the entrance width, and also the continental shelf width were identified as the best explanatory variables of estuarine fish species richness at a large scale. Our approach provides a standardized method to estimate the relationship between fish assemblages and environmental factors. This constitutes a first step in assessing estuarine ecological status and studying the effects of additional factors such as anthropogenic disturbances.
(Estuarine, Coastal and Shelf Science. vol. 86, n° 0272-7714, pp. p. 137 - p. 147, 11/04/2026)
UR EPBX, CEMAGREF, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ESE, INRA, ULISBOA
The European carbon balance. Part 3: forests
(Global Change Biology. vol. 16, n° 1354-1013, pp. 1429-1450, 11/04/2026)
LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, ICOS-ATC, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, MPI-BGC, UNITUS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EPHYSE, INRA, CNR, UNIBO, EFI, TKK, VU, ICOS-RAMCES, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, MOSAIC, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA
Trace Element Concentrations (Mercury, Cadmium, Copper, Zinc, Lead, Aluminium, Nickel, Arsenic, and Selenium) in Some Aquatic Birds of the Southwest Atlantic Coast of France
Trace elements (mercury [Hg], cadmium [Cd], copper [Cu], zinc [Zn], lead [Pb], aluminium [Al], nickel [Ni], arsenic [As], and selenium [Se]) were investigated using inductively coupled plasma–mass spectrometry in liver, kidney, muscle, and feather of aquatic birds wintering or inhabiting the wetlands situated on the Southwest Atlantic coast of France. A majority of greylag geese, red knots, and grey plovers were collected from among hunter-shot animals. The relation between residue concentrations, age (juvenile vs. adult), and sex was investigated. Trace elements were lower than threshold levels of toxicity, except for Pb. Greylag geese sampled could be considered Pb-poisoned. These consequential levels of contamination could be the result of the ingestion of Pb-shot from ammunition used in hunting areas they crossed during migration. Cd accumulation increased with age, whereas Pb levels in feathers were lower in adult birds in connection with moulting. As was influenced by sex. Female birds displayed higher concentrations in liver and feathers than did male birds.
(Archives of Environmental Contamination and Toxicology. vol. 58, n° 0090-4341, pp. 844 - 853, 11/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IPREM, UPPA, INC-CNRS, CNRS
Effects of dietary cadmium contamination on bird Anas platyrhynchos—Comparison with species Cairina moschata
This study aimed to assess the effect of two dietary cadmium (Cd) levels (C1: 1 mg kg−1; C10: 10 mg kg−1) on bird Anas platyrhynchos exposed for 10, 20 and 40 days (5 animals per experimental condition). Ducks were able to accumulate high amounts of Cd, especially in kidneys (after 40 days: C1 8.1±1 mg kg−1, C10 37.7±4.3 mg kg−1). After 40 days, the lowest Cd level triggered oxidative stress and stimulated mitochondrial metabolism. At the same time, highest amounts of Cd (C10 group) only triggered repression of genes encoding for catalase and acetyl-CoA carboxylase, with repression factors of 1/50 and 1/5, respectively. High dose exposures were then associated with the repression of genes encoding for antioxidant, whereas low dose exposure triggered their induction. In contrast, the onset of MT gene expression appeared quickly for the C10 group even if a time delay was observed between gene expression and protein accumulation. Through the comparison of A. platyrhynchos and Cairina moschata, the response to Cd toxicity appeared species-dependent. Discrepancies between species could be explained by differential utilization of MT. This pathway of detoxification seemed sufficient to counter Cd toxicity.
(Ecotoxicology and Environmental Safety. vol. 73, n° 0147-6513, pp. 2010-2016, 11/04/2026)
IPREM, UPPA, INC-CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UEPFG, INRA, URA, INRA