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, 24/02/2026)
CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR REBX, CEMAGREF, VAST
Formation of Thetis Deep metal-rich sediments in the absence of brines, Red Sea
Almost all Red Sea deeps contain metal-rich sediments covered by brine pools. It is generally agreed that these metal-rich deposits precipitated from overlying metal-rich brines that originated from migrating hydrothermal fluids. No brine pool has ever been reported in Thetis Deep, inciting us to evaluate if such a brine layer ever occurred in the deep during the past. In order to address that questioning, a study combining mineralogical, geochemical (major-, minor-, rare-earth elements) and isotopic (Sr. Nd. Pb) approaches was completed on cored sediments and extracted interstitial waters from inside and outside the deep.;The sediments have an overall hydrothermal origin, as shown by the REE concentrations and patterns, metal contents, and Pb-Nd isotopic data, all pointing to a mantle signature. The intensity of the hydrothermal activity varied with time in the deep; the most intense episode resulting in an almost pure Fe-oxi-hydroxide layer. Varied chemical arguments, especially the Zr and REE data of the sediments, favor the fact that the whole sedimentation in Thetis Deep occurred in the absence of a stable, salt-rich and mineralized brine pool, and that no brine layer ever existed. This conclusion is supported by the constant Sr isotope composition of the sediment and its interstitial waters that are almost identical to that of the Red Sea seawater. The study also suggests that hydrothermal activity monitored fluid supplies that interacted differently with seawater in the different Red Sea deeps, resulting in an overall formation of metal-rich sediments, but along varied local conditions. (C) 2009 Elsevier B.V. All rights reserved.
(Journal of Geochemical Exploration. vol. 104, n° 0375-6742, pp. 12-26, 24/02/2026)
LHyGeS, ENGEES, UNISTRA, INSU - CNRS, CNRS, UAG, INSU - CNRS, UM, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Recent expansion of the oriental shrimp Palaemon macrodactylus (Crustacea: Decapoda) on the western coasts of France
The invasive oriental shrimp Palaemon macrodactylus Rathbun, 1902 has considerably extended its distribution in transitional waters along the Atlantic and Channel coasts of France during the period 2007-2010. The most probable method of a primary introduction of this species is ballast waters, but passive transport by water currents is also a possible mechanism of colonization (secondary introductions). Palaemon macrodactylus is a powerful invader of transitional waters and these new populations should be monitored in the future to assess any consequences to native species.
(Aquatic Invasions. vol. 5, n° 1798-6540, pp. S103-S108, 24/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR EPBX, IRSTEA, IRSTEA, LIENSs, INSU - CNRS, ULR, CNRS, IFREMER
Early Holocene Laurentide Ice Sheet deglaciation causes cooling in the high-latitude Southern Hemisphere through oceanic teleconnection
The impact of the early Holocene Laurentide Ice Sheet (LIS) deglaciation on the climate at Southern Hemisphere high latitudes is studied in three transient simulations performed with a global climate model of the coupled atmosphere-ocean-vegetation system. Considering the LIS deglaciation, we quantify separately the impacts of the background meltwater fluxes and the changes in topography and surface albedo. In our model, the meltwater input into the North Atlantic results in a substantial weakening of the Atlantic meridional overturning circulation, associated with absence of deep convection in the Labrador Sea. Northward ocean heat transport by the Atlantic Ocean is reduced by 28%. This weakened ocean circulation leads to cooler North Atlantic Deep Water (NADW). Upwelling of this cool NADW in the Southern Ocean results in reduced surface temperatures (by 1°C to 2°C) here between 9 and 7 ka compared to an experiment without LIS deglaciation. Poleward of the polar front zone, this advective teleconnection between the Southern and Northern hemispheres overwhelms the effect of the "classical" bipolar seesaw mechanism. These results provide an explanation for the relatively cold climatic conditions between 9 and 7 ka reconstructed in several proxy records from Southern Hemisphere high latitudes, such as Antarctic ice cores. ,
(Paleoceanography. vol. 25, n° 0883-8305, pp. PA3204, 24/02/2026)
VU, TECLIM, ELI, UCL, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, CLIM, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA
Deglacial environments in eastern Prydz Bay, East Antarctica
A high-resolution continuous record of diatom census counts and diatom specific biomarkers in sediment core NBP0101-JPC24 allows assessment of oceanographic and environmental conditions in eastern Prydz Bay during the deglaciation (11 100e9000 cal yr BP) at decadal timescale. Our study improves previous snapshots investigations based on resin-embedded thin sections and presents a new proxy that compliments the diatom census counts. Our results suggest that the ice sheet retreat over the core site is dated ate11 100 cal yr BP, setting the onset of local deglaciation and subsequent open marine conditions. The glacial retreat in Prydz Bay is due to global warming initiated at 18 cal ka BP and the regional development of the Prydz Bay cyclonic gyre. Our results further demonstrate that the deglaciation in eastern Prydz Bay can be separated in four phases: the first between 11 100 and 10 900 cal yr BP when the ice shelf was proximal and sea ice was almost perennial; the second and the third phases between 10 900e10 400 cal yr BP and 10 400e9900 cal yr BP, respectively, when the ice shelf retreated and seasonal sea ice cycle consequently developed promoting warmer water to pump into the bay within the gyre, which in turn forced the ice shelf recession and the yearly sea ice cycle establishment; and the fourth between 9900 and 9000 cal yr BP when Holocene condition were set with a recurrent seasonal sea ice cycle and a well established Prydz Bay gyre.
(Quaternary Science Reviews. vol. 29, n° 0277-3791, pp. 2731-2740, 24/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LOCEAN, IPSL, ENS-PSL, PSL, UVSQ, UPMC, CEA, INSU - CNRS, X, IP Paris, CNES, CNRS, MNHN, IRD, UPMC, INSU - CNRS, CNRS
Sedimentary archives of the French Atlantic coast (inner bay of Vilaine, south Brittany) : depositional history and late Holocene climatic signals.
(Continental Shelf Research. vol. 30 (10–11), n° 0278-4343, pp. 1250–1266, 24/02/2026)
PEPS, UCBL, INSU - CNRS, CNRS, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, CEREGE, IRD, INRA, AMU, CdF (institution), INSU - CNRS, CNRS, LETG, UNICAEN, NU, UA, EPHE, PSL, UBO EPE, UR2, CNRS, IGARUN, UN, LDO, INSU - CNRS, UBO EPE, CNRS, GEOARCHI, UBS, UBO EPE, IBSHS, UBO EPE
Estimating turbidity and total suspended matter in the Adour River plume (South Bay of Biscay) using MODIS 250-m imagery
The Basque coastal waters (South Bay of Biscay) are directly influenced by the Adour River freshwater plume. The Adour outflow leads to important variations of suspended matter concentrations and turbidity, which in turn may affect biological productivity and water quality. This study aims at both developing specific algorithms and testing the efficiency of atmospherically corrected MODIS-Aqua 250-m surface reflectance product (MYD09) to map total suspended matter concentrations and turbidity within the Adour coastal region. First, regional empirical algorithms based on in-situ data were tested to retrieve the concentration of total suspended matter and turbidity from the remote sensing reflectance. Then, the respective sensitivity of MODIS surface reflectance bands 1 and 2 for water quality application was investigated as well as the quality of atmospheric corrections. Finally, selected algorithms were applied to the MYD09 product. The resulting 250-m resolution maps were then compared to 1000-m maps produced by IFREMER and comparisons between satellite measurements and in-situ sampling points were performed. Results show that MODIS-Aqua band 1 (620-670 nm) is appropriate for predicting turbidity and total suspended matter concentrations using polynomial regression models, whilst band 2 is unadapted. Comparison between total suspended matter concentration 250-m resolution maps and mineral suspended matter 1000-m maps (generated by IFREMER) produced consistent results. A high correlation was obtained between turbidity measured in-situ and turbidity retrieved from MODIS-Aqua satellite data. (C) 2009 Elsevier Ltd. All rights reserved.
(CONTINENTAL SHELF RESEARCH. vol. 30, pp. 379-392, 24/02/2026)
IFREMER, DYNECO, IFREMER, LOV, INSU - CNRS, SU, CNRS, IMEV, INSU - CNRS, SU, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Relationships between sinking particulate matter, early diagenesis, and sedimentary recording in the Bay of Biscay margin)
(24/02/2026)
LPGN, UN, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Methane sources, sinks and fluxes in a temperate tidal lagoon: The Arcachon Lagoon (SW France)
(Estuarine, Coastal and Shelf Science. vol. 89, n° 0272-7714, pp. 256-266, 24/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LMTG, UT3, Comue de Toulouse, CNRS, COM, INSU - CNRS, CNRS, BOME, MNHN, UPMC, CNRS, LEMAR, IRD, IFREMER, UBO EPE, CNRS, CNRS
Interactive effects of metal contamination and pathogenic organisms on the marine bivalve Cerastoderma edule
The present study evaluated the interactive effects of cadmium contamination and pathogenic organisms (trematodes Himasthla elongata and bacteria Vibrio tapetis) singularly and in combination during 7 days on the bivalve Cerastoderma edule. Some defense-related activities were analyzed such as genetic expression, metallothionein and immune responses. Trematode metacercarial infection, similar whatever the treatment, induced the strongest responses of immune parameters. Particularly, the interaction between cadmium and parasite exposures induced unusual responses on gene expression and immune responses. No effect of bacterial challenge appeared on bivalve responses, nevertheless a strong mortality of V. tapetis infected cockles occured between 7 and 14 days. Cadmium bioaccumulation was significantly modulated by both pathogenic organisms. Furthermore, an antagonistic effect of trematodes and bacteria was shown on metal bioaccumulation of co-infected cockles. These results highlighted the importance of considering the multiplicity of perturbation sources in coastal ecosystems to assess the health status of organisms.
(Marine Pollution Bulletin. vol. 60, n° 0025-326X, pp. 515-525, 24/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEMAR, IRD, IFREMER, UBO EPE, CNRS