Usages et qualité sur un territoire ostréicole
Ce rapport présente les résultats issus de recherches menées sur le Bassin d'Arcachon dans le cadre du projet de recherche OSQUAR, financé par la région Aquitaine. Il s'agit plus particulièrement du rapport du volet 2 du projet, qui mobilisait SHS et sciences du milieu sur la question des usages sur le territoire du Bassin d'Arcachon en lien avec la qualité du milieu.
(pp. 273, 27/10/2026)
UR ADBX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Influence of organic matter from urban effluents on trace metal speciation and bioavailability in river under strong urban pressure
In aquatic systems, dissolved organic matter (DOM) constitutes a key component of the carbon cycle controlling the transport, speciation, bioavailability, and toxicity of trace metals. In this work, we study the spatiotemporal variability of the MO in terms of both quality and quantity from upstream to downstream the Parisian conurbation. Urban discharges which are the main source of allochthonous organic matter into the Seine at low-water periods were also investigated. The DOM collected was fractionated according to polarity criteria into five fractions: hydrophobic, transphilic, hydrophilic acid, hydrophilic basic, and hydrophilic neutral. Due to urban discharges, a strong enrichment in the hydrophilic (HPI) fraction was observed for downstream sites. This hydrophilic fraction presented stronger binding capacities for copper than hydrophobic fraction from less urbanized site (upstream from Paris) and Suwannee river fulvic acid (SRFA). Furthermore, biotests highlighted a significant copper bioavailability decrease in presence of hydrophilic DOM. \textcopyright 2013 Zhejiang University Press and Springer Science+Business Media Dordrecht. All rights are reserved.
(. vol. 9789400756342, pp. 517--521, 27/10/2026)
LEESU, UPEM, ENPC, UPEC UP12, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR HBAN, IRSTEA, CEREVE, ENPC, UPEC UP12
Polychlorinated Biphenyls, Polybrominated Diphenyl Ethers, and Phthalates in Roach from the Seine River Basin (France): Impact of Densely Urbanized Areas
Endocrine disruptors (EDs) from three chemical classes—polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and phthalates—were investigated in the Seine River and one tributary, the Orge River, upstream and downstream of urban areas. The impact of urban areas was characterized by a concentration increase of all compounds in the Seine River and for phthalates and PBDEs in the Orge River. In the Seine River, from upstream (Marnay) to downstream (Triel) of urban areas, water concentration increases were greater for diethylhexyl phthalate (DEHP) (6 times, p < 0.05) and ∑tri-hexa BDE (5 times [p < 0.05]) than for ∑7PCBi (2.6 times). Simultaneously, sediments displayed a strong accumulation of contaminants downstream and compared with upstream values, their concentrations increased greatly: 202-fold for DEHP, 69-fold for BDE209, 25-fold for ∑tri-hexa-BDE, and 11-fold for ∑7PCBi. Variations of fish ED concentrations gave an indication of their habitat contamination increase observed downstream of densely urbanized areas of the Seine River, especially for PBDEs (∑tri-hexa-PBDEs = 14-fold increase ≤15.7 ± 6.9 ng g−1 dry weight [dw; p < 0.001]) and for PCBs (∑7PCBi eightfold increase ≤211 ± 55 ng g−1 dw [p < 0.01]). PCA results highlighted relationships between the different ED classes. A correlation (p < 0.05) was observed between PCB and PBDE fish concentrations, suggesting common sources and similar absorption mechanisms. For PCBs, which were poorly biodegraded, the bioaccumulation factor was strongly correlated (p < 0.001) to molecular hydrophobicity, whereas for PBDEs a negative correlation (p < 0.05) was observed related active debromination processes. This multichemical study investigates for the first time the occurrence of a wide range of EDs in roach, which was chosen as a sentinel species for this survey of surface water contamination.
(Archives of Environmental Contamination and Toxicology. vol. 66, n° 0090-4341, pp. 41-57, 27/10/2026)
SISYPHE, UPMC, EPHE, PSL, PSL, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Hydrological variability of major French rivers over recent decades, assessed from gauging station and GRACE observations
This study was carried out in the framework of the Surface Water and Ocean Topography (SWOT) programme of the French National Centre of Space Studies (CNES). Based on discharge measurements and Gravity Recovery and Climate Experiment (GRACE) determination of total water storage (TWS), we have investigated the hydrological variability of the main French drainage basins (Seine, Loire, Garonne and Rhône) using a wavelet approach (continuous wavelet analyses and wavelet coherence analyses). The results of this analysis have shown a coherence ranging between 82% and 90% for TWS and discharge, thus demonstrating the potential use of TWS for characterization of the hydrological variability of French rivers. Strong coherence between the four basin discharges (between 73% and 92%) and between their associated TWS data (from 82% to 98%) suggested a common external influence on hydrological variability. To determine this influence, we investigated the relationship between hydrological variability and the North Atlantic Oscillation (NAO), considered as an index of prevailing climate in Europe. Basin discharges show strong coherence with NAO, ranging between 64% and 72% over the period 1959–2010. The coherence between NAO and TWS was 62% to 67% for 2003–2009. This is similar to the coherence between NAO and basin discharges detected for the same period. According to these results, strong influence of the NAO was clearly observed on the TWS and discharges of the major French river basins.
(Hydrological Sciences Journal. vol. 59, n° 0262-6667, pp. 1844 - 1855, 27/10/2026)
M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, IRD, UPVD, AU, UR, UM, UG, UA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Etude intégrée de l’effet des apports amont et locaux sur le fonctionnement de la Garonne estuarienne (ETIAGE) : Rapport année 3 Avril 2012 - Mars 2013 Addemdum
Le programme ETIAGE a été mis en place avec pour objectif de répondre aux questions suivantes : que représentent les apports des effluents de la Communauté Urbaine de Bordeaux (CUB) par rapport à ceux venant de l’amont en termes de charge organique et de micro-polluants ? Quels rôles sur le devenir des effluents jouent la présence du bouchon vaseux et la stagnation résiduelle des eaux (déplacement net entre mouvement de flot et de jusant) au niveau de l’estuaire fluvial amont en période d’étiage estival ? Réciproquement, à quels moments et jusqu’où s’étend l’impact de ces effluents sur la qualité des eaux de la Garonne estuarienne ? Quelles incidences des effluents sur le comportement des populations biologiques en place ou migratoires dans la Garonne estuarienne ? Quelle tendance évolutive va connaître l’oxygénation des eaux ? Quel sera l’impact sur le comportement des micro-polluants et des populations biologiques ? Quelles recommandations de gestion pourraient être préconisées à partir de la synthèse des pressions exercées sur les eaux de la Garonne estuarienne ? Le programme est divisé en 5 axes, dont les bilans de travail sont présentés axe par axe.
(pp. 409, 27/10/2026)
UR EPBX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Genotoxic effects of exposure to waterborne uranium, dietary methylmercury and hyperoxia in zebrafish assessed by the quantitative RAPD-PCR method
Release of chemicals and fluctuation in oxygen content in the aquatic environment represent hazards for fish health. The present study aims at assessing the genotoxic impact of low concentration exposures to waterborne uranium (U), dietary methyl mercury (MeHg) and hyperoxia in zebrafish by using the RAPD-PCR quantitative method. A significant increase of the number hybridization sites was observed in fish exposed to 30 μg U/L and 100 μg U/L and hyperoxia. In fish exposed to MeHg (13.5 μg Hg/g, dry weight) no change in the number of hybridization sites were found, however, the frequency of PCR products showed significant variation. The mechanisms of toxicity leading to DNA damage in fish exposed to waterborne uranium, mercury and hyperoxia are discussed and the results from the literature given by the comet assay, micronucleus test and RAPD-PCR method compared. The study provides new data regarding the genotoxic effects of MeHg, hyperoxia and low U concentrations (30 μg U/L) in fish. The present work highlights the use of the RAPD-PCR as a sensitive method in the assessment of chemically-induced DNA damage in animals.
(Mutation Research - Genetic Toxicology and Environmental Mutagenesis. vol. 755, n° 1383-5718, pp. 55-60, 27/10/2026)
LIENSs, INSU - CNRS, ULR, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IRSN/PRP-ENV/SERIS/LECO, IRSN/PRP-ENV/SERIS, IRSN
Budget of methane emissions from soils, livestock and the river network at the regional scale of the Seine basin (France)
We used various approaches to establish a comprehensive budget of methane (CH4) emissions from the Seine basin, including direct emissions from livestock and soils as well as emissions from the drainage network. For the direct emissions from livestock, we used official livestock census numbers and emission factors (CH4 emitted by each animal species per head per year) available in the literature. For the emissions from soils, we based our estimates on experimental measurements in closed chambers installed on different agricultural plots, forest, and grasslands in 2008 and 2009. The results were extrapolated to the whole Seine basin, including grassland, cropland, and forest soil distributions in the Seine basin. The CH4 emissions from the Seine drainage network were also based on measurements of sampled waters in various rivers and streams (from headwaters to estuary) during different seasons in 2007, 2008, and 2010. After chemical analysis of CH4 concentrations in the water samples using a gas chromatographic technique and calculation of the CH4 supersaturation by stream order in rivers of the Seine basin (from 1 to 8) and by season we could estimate the CH4 emissions for the whole water surface area of the Seine drainage network. The livestock of the Seine basin produce CH4 emissions amounting to 166 × 106 kg C year−1, among which cattle are responsible for 85 %. The total CH4 emission from the Seine drainage network was estimated at 0.3 × 106 kg C year−1, large rivers being responsible for the largest proportion. Ebullition could account for an additional 0.2 × 106 kg C year−1. Soils of the Seine basin are a net sink for CH4 (9.4 × 106 kg C year−1). The water and soils fluxes are low with regard to emissions by livestock, but domestic waste, through landfills, could contribute an additional 40 × 106 kg C year−1.
(Biogeochemistry. vol. 116, n° 0168-2563, pp. 199-214, 27/10/2026)
SISYPHE, UPMC, EPHE, PSL, PSL, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EGC, INRA
Vulnerability of sandy coasts to climate variability
The main objective of the VULSACO (VULnerability of SAndy COasts to climate change and anthropic pressure) project was to investigate present day and potential future vulnerability of sandy coasts at the 2030 horizon, i.e. on a time scale related to climate variability. The method, based on a multidisciplinary approach bringing together geologists, geographers, physicists, social psychologists, engineers and stakeholders, was structured around 4 axes: field data analysis; numerical modelling; analysis of governance and stakeholder perceptions; and development of vulnerability indexes. This approach was designed to investigate vulnerability at a local scale and was applied to 4 contrasting beaches located in France: Sète Lido (Mediterranean Sea), Truc Vert and La Tresson beaches (Atlantic Ocean), and Dewulf (English Channel). The results focus on decadal and multi-annual beach trends at the Truc Vert beach site. There is almost no trend in beach volume at Truc Vert beach, although there is a variation in this parameter on a cycle of 2 to 3 yr, with variations related to wave energy and probably to indexes of climate variability. Numerical modelling identified the sensitivity of beach responses to changes in wave height and direction, especially in terms of subtidal morphology and the potential development of shoreline instability. Together with the observed offshore wave angle at the Biscay Buoy, these model results suggest that a potential change in wave angle due to climate variability could significantly modify the bars’ morphology. The combination of data analysis and numerical modelling contributed to the development of vulnerability indexes designed for sandy coasts, which take into account climate-dependant variables such as waves. This allowed the differentiation of the sites in terms of vulnerability to erosion: Sète Lido and Truc Vert beach were the most and least vulnerable sites, respectively. These indexes help in identifying the dominant components of beach vulnerability, and provide potential for the study of how anthropogenic factors affect vulnerability. The study of stakeholder perceptions and decision-making with regard to climate-related risk also highlighted potential anthropogenic effects on beach vulnerability, and identified possible site-specific outcomes.
(Climate Research. vol. 57, n° 0936-577X, pp. 19-44, 27/10/2026)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UAG, INSU - CNRS, UM, CNRS, UPC, CEFREM, UPVD, INSU - CNRS, CNRS, LETG, UNICAEN, NU, UA, EPHE, PSL, UBO EPE, UR2, CNRS, IGARUN, UN, UC / UniCan, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France], ULCO, LEGI, UJF, Grenoble INP, CNRS
Estimation of a time varying extreme quantile with application to the measurement of the activity of bivalves in an environmental contex
(27/10/2026)
LMBA, UBS, UBO EPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Deglacial and Holocene vegetation and climatic changes in the southern Central Mediterranean from a direct land–sea correlation
Despite a large number of studies, the long-term and millennial to centennial-scale climatic variability in the Mediterranean region during the last deglaciation and the Holocene is still debated, including in the southern Central Mediterranean. In this paper, we present a new marine pollen sequence (core MD04-2797CQ) from the Siculo-Tunisian Strait documenting the regional vegetation and climatic changes in the southern Central Mediterranean during the last deglaciation and the Holocene. The MD04-2797CQ marine pollen sequence shows that semi-desert plants dominated the vegetal cover in the southern Central Mediterranean between 18.2 and 12.3 ka cal BP, indicating prevailing dry conditions during the deglaciation, even during the Greenland Interstadial (GI)-1. Across the transition Greenland Stadial (GS)-1 -Holocene, Asteraceae-Poaceae steppe became dominant till 10.1 ka cal BP. This record underlines with no chronological ambiguity that even though temperatures increased, deficiency in moisture availability persisted into the early Holocene. Temperate trees and shrubs with heath underbrush or maquis expanded between 10.1 and 6.6 ka, corresponding to Sapropel 1 (S1) interval, while Mediterranean plants only developed from 6.6 ka onwards. These changes in vegetal cover show that the regional climate in southern Central Mediterranean was wetter during S1 and became drier during the mid-to late Holocene. Wetter conditions during S1 were likely due to increased winter precipitation while summers remained dry. We suggest, in agreement with published modeling experiments, that the early Holocene increased melting of the Laurentide Ice Sheet in conjunction with weak winter insolation played a major role in the development of winter precipitation maxima in the Mediterranean region in controlling the strength and position of the North Atlantic storm track. Finally, our data provide evidence for centennial-scale vegetation and climatic changes in the southern Central Mediterranean. During the wet early Holocene, alkenone-derived cooling episodes are synchronous with herbaceous composition changes that indicate muted changes in precipitation. In contrast, enhanced aridity episodes, as detected by strong reduction in trees and shrubs, are recorded during the mid-to late Holocene. We show that the impact of the Holocene cooling events on the Mediterranean hydroclimate depend on baseline climate states, i.e. insolation and ice sheet extent, shaping the response of the mid-latitude atmospheric circulation.
(Climate of the Past. vol. 9, n° 1814-9324, pp. 767-787, 27/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, PALEOCEAN, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, FSS, BTP, LOCEAN, IPSL, ENS-PSL, UVSQ, UPMC, CEA, INSU - CNRS, X, CNES, CNRS, MNHN, IRD, UPMC, INSU - CNRS, CNRS, LCE, CNRS, UMLP, GEOPS, UP11, CNRS, CNRS