Contamination des sols français par les résidus de pesticides
La contamination de l’environnement par les résidus de pesticides est une préoccupation croissante par les acteurs publics au vu de leur omniprésence dans tous les milieux et leurs impacts directs et indirects sur la biodiversité et la santé humaine. Cependant, les études traitant de la contamination des sols par les résidus de pesticides sont très peu nombreuses, témoignant du manque de connaissance sur l’état de la contamination des sols et les impacts potentiels sur la biodiversité. Le projet Phytosol, financé entre 2018 et 2022 par l’Anses et coordonné par INRAE a permis d’acquérir des données inédites de 111 substances sur 47 sols prélevés dans le cadre du Réseau de mesures de la qualité des sols (RMQS). Les résultats de cette étude, détaillés dans le rapport suivant et publiés en 2023 dans la revue Environmental Science Technology, démontrent ainsi que 98% des sols prélevés contiennent au moins un résidu de pesticides, y compris des sites sans traitements phytosanitaires tels que les prairies permanentes, les sols forestiers ou encore des sols de parcelles en agriculture biologique. L’évaluation des risques indique également un risque modéré à fort pour les vers de terre notamment dans les sols de grandes cultures. Enfin, la confrontation avec les applications de produits phytosanitaires a mis en évidence la présence de certaines substances bien au-delà de leur temps de dégradation théorique et à des concentrations supérieures à celles attendues. Le déroulement de l’étude (mise en place, méthodologie) ainsi que les résultats détaillés sont présentés dans ce rapport.
(15/07/2026)
Info&Sols, INRAE, LPTC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Evaluating migration hazard for recently remobilized managed coastal dunes
Sparsely vegetated or unvegetated coastal dunes are inherently dynamic, regardless of their size (Hesp et al., 2022). A salient characteristic of these dunes is their landward migration, driven by prevailing onshore winds, at rates that can exceed several meters per year. The rapid evolution of freely evolving coastal dunes inevitably raises concerns about the burial of infrastructure and more generally, the back dune areas. In a context where dune system remobilization is emerging as a nature-based management solution with multiple benefits (ecological reconnection, chronic marine erosion and sea-level rise effects mitigation), precise, spatially explicit quantitative assessments of dune migration hazards are essential. This is more critical given the trends of increasing urbanization and the concentration of socio-economic interests in coastal zones. Along the 230 km of the Aquitaine coast (southwest France), coastal dunes, which landscape is largely inherited from nearly two centuries of management, stabilization, and episodic mechanical re-profiling, have undergone spontaneous remobilization over the past decade (Nicolae Lerma et al., accepted). Across extensive sectors, dunes have transitioned from geometrically fixed, vegetated forms to aerodynamic, transgressive dunes (Figure 1a). This shift presents both opportunities and challenges for short- and long-term management strategies but also raises critical questions about accommodating rapid migration rates and evolving dune morphology. Current approaches to assessing burial hazards often overlook key parameters, such as interannual wind variability, climate change-induced trends in forcing, dune and back-dune morphology, and sediment budgets. Furthermore, methods relying on historical migration rates are inapplicable in regions where dunes were artificially stabilized during the 20th century through management interventions. Using annual airborne LiDAR data (Figure 1b.) and simulations with the morphodynamic model DUNA (Kombiadou et al., 2023, Figure 1c.), we analyze the factors influencing the migration speed of recently unvegetated dunes. We also investigate the impact of hybrid management strategies (designed to either accelerate or mitigate dune remobilization) at large spatial scales (hundreds of meters to tens of kilometers).
(13/07/2026)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ONF
Early development of a restored dune system positioned in front of a dyke on a chronically eroding microtidal urban shoreline
Coastal dunes are globally recognized as natural features that can be important adaptation approaches for climate change along urban and natural coastal system. The aim of the study is to investigate the effects of sand trapping fences installed in front a grey dyke along a 2300-meter stretch of coastline in St. Marie-La-Mer (Southeastern France) in November 2021. This area has been experiencing severe chronic erosion for several decades. The methodology involves analyzing bi-annual topographic Lidar surveys conducted between May 2020 and September 2023, along with an examination of hydro-meteorological conditions. The research indicates several sediment balances within the traps between October 2021 and September 2023, with volumes in stability -0.05 m3/m2 (-14 m3) at the more eroding zone and in exceeding between 0.2 and 0.35 m3/m2 (1200 m3) elsewhere. The erosive trend preceding October 2021 has ceased, with each DEM demonstrating stability or gain. Throughout the study, the beach’s sediment budget remains negative (ranging between -0.12 and -0.27 m3/m2, -6100 m3) except in SA2. Thus, despite adverse conditions for aeolian sediment transport and deposition, such as narrow and steep beach, predominant offshore wind, coarse grain size, limited sediment supply, slow vegetal colonization, along with persistent erosion of the lower beach, initial stages of upper beach restoration are encouraging. Moreover, this soft dune management approach is expected to mitigate the impacts of major storm events. This was observed in 2021 and 2022 where two significant storms (Hs>5m), had minimal impact on the upper beach compared to past incidents where similar conditions led to deterioration of the incipient dune and the dyke. This study provides valuable insights into the implementation of such systems in environments prone to chronic erosion and unfavorable conditions for aeolian sediment transport
(12/07/2026)
BRGM, UniFE, UM, UM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UB
Coastal barchanoid dunes differentiation and evolution model: Cap Ferret Spit, Aquitaine Coast France
Barchanoid dunes fields are commonly observed in both desert and coastal areas. However, while they are relatively well known in arid settings, their internal architecture, dune morphology and evolution processes in coastal environments are rarely documented in the literature. This study investigates coastal barchanoid dunes along the Cap Ferret Spit (southwest France) by combining high-resolution LiDAR data (1 m spatial resolution) with an extensive ground-penetrating radar (GPR) survey (>70 km of profiles). Five distinct dune morphotypes are identified along an ocean-spit-lagoon continuum, as modern foredune, embryonic dunes, proto-barchans, barchanoid ridges, and isolated barchans. Morphometric analyses reveal systematic relationships between dune size, elevation, and internal structure, with crest elevations ranging from 5 m in proto-barchans to 40 m in barchanoid ridges and isolated barchans. GPR profiles image lee-side accretion strata, reactivation surfaces, superimposed structures, and dune-dune interaction features, demonstrating that proto-barchans grow through stacking before evolving into barchanoid ridges and subsequently fragmenting into isolated barchans. The Cap Ferret dune system enables observation of preliminary and intermediate developmental stages of barchanoid dunes rarely documented in the literature, from embryonic dunes through proto-barchans and compound forms to isolated barchans. Second-order morphologies, including superimposed bedforms and wavy patterns with transverse orientation, occur systematically across all dune types and record short-term reactivation processes driven by dominant winds and potential vegetation interactions. These findings provide a reference model for coastal dune morphodynamic transitions including interactions between aeolian, hydrologeological and biotic processes. It also contributes to refining conceptual and numerical models of dune-field evolution by incorporating coastal boundary conditions.
(Geomorphology. vol. 511, n° 0169-555X, pp. 110441, 10/07/2026)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Crises hydriques et recomposition des systèmes irrigués en zone semi-aride : le cas du périmètre Manombo–Andoharano–Mamovoky (Sud-Ouest malgache)
La région Sud-Ouest de Madagascar est particulièrement vulnérable au dérèglement climatique en raison de son climat semi-aride, caractérisé par des températures élevées et des précipitations faibles et irrégulières. Le changement climatique accentue les sécheresses, provoque une forte variabilité des pluies et retarde le début des saisons pluvieuses, tout en réduisant leur durée. Les projections climatiques indiquent également une augmentation importante des températures dans cette région, ce qui aggrave la rareté de l’eau et affecte directement les ressources en eau de surface ainsi que le développement agricole. Le périmètre irrigué d’Andoharano-Mamovoky, alimenté par le fleuve Manombo via le barrage d’Andoharano, illustre ces enjeux hydrologiques et agricoles. Le débit du Manombo est très variable et la grande majorité de l’eau prélevée est destinée à l’irrigation. Cette forte dépendance à une ressource instable rend le système irrigué vulnérable aux déficits hydriques, notamment en saison sèche. Dans ce contexte, l’étude cherche à comprendre comment les changements du régime hydrologique influencent les rapports sociaux, les inégalités d’accès à l’eau et les conflits entre les usagers du périmètre irrigué. L’étude adopte une approche méthodologique combinant analyses hydrologiques et climatiques, entretiens avec les usagers et observations de terrain. Les résultats montrent une récurrence des années sèches et une baisse de la disponibilité en eau, ce qui accentue les tensions entre agriculteurs. Les communautés développent différentes stratégies d’adaptation, comme l’ajustement des calendriers agricoles et la mise en place de tours d’eau. Toutefois, ces réponses restent limitées par des infrastructures hydrauliques insuffisantes et des inégalités d’accès à l’eau, ce qui fragilise la résilience du système irrigué à long terme et souligne la nécessité de renforcer la gouvernance et les infrastructures hydrauliques.
(09/07/2026)
LAM, IEP Bordeaux, IRD, UBM, CNRS, UBM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
PFAS Data Hub: An open data portal featuring geovisualisation
Per-and polyluoroalkylated substances (PFAS) are a group of man-made chemical substances used in everyday products and industry processes since the 1950s. They contain carbon-fluorine bonds, among the strongest in chemistry, resulting in intrinsic or indirect extreme environmental persistence and earning them the nickname "forever chemicals". In a context of growing awareness of PFAS toxicity and widespread pollution, the Forever Pollution Project (FPP), a cross-border journalistic investigation, compiled data on measured and estimated PFAS contamination across Europe, published as an interactive map. In this data paper we present the PFAS Data Hub (PDH), a project building upon the FPP dataset and reprocessing it using a more robust and transparent methodology. We incorporated several additional data sources, most of which are automatically updated on a monthly basis. To our knowledge, this constitutes the only compilation of PFAS contamination data at the European scale. It is intended to support research projects across a wide range of different disciplines, and to be used as a source of information by journalists, citizens and civil society organisations. The data, as well as a geovisualisation tool with filtering and export options, is available on the PDH website: https://pdh.cnrs.fr.
(03/07/2026)
LIS, AMU, UTLN, CNRS, PRODIG (UMR_8586 / UMR_D_215 / UM_115), UP1, IRD, SU, CNRS, UPCité, IRISSO, PSL, CNRS, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Effect of the microparasite Perkinsus olseni on the bioturbation activity and engineering potential of the Manila clam Ruditapes philippinarum
Host behavioral modifications induced by parasites can have profound ecological consequences, especially when they affect ecosystem engineers such as bioturbators. While the influence of macroparasites on host behavior and, by extension, on ecosystem functioning is documented in the marine realm, the role of microparasites remains unexplored. The association between Perkinsus olseni, a widespread microeukaryotic parasite, and the Manila clam Ruditapes philippinarum, an abundant bioturbator in many coastal soft-bottom environments, is an interesting model for investigating this overlooked aspect. Infection by P. olseni has been shown to alter various physiological parameters in clams, such as immune response, metabolic activity, and reproductive performance. However, whether these internal disruptions translate into behavioral changes, such as modifications in sediment particle transports initiated by clams, remains an open question. In this study, we explore whether infection by P. olseni influences the bioturbation activity of the Manila clam, a process with significant implications for ecosystem processes, such as nutrient fluxes, in coastal environments. We did not report major changes in the engineering potential of the Manila clam when infected with non-lethal doses of Perkinsus olseni. However, we noticed a subtle increase in the magnitude of sediment transport activities, which may reflect behavioral adaptations. Given the ecological role of R. philippinarum as a driver of benthic processes, even little parasiteinduced behavioral shifts could cascade down to affect ecosystem processes such as sediment dynamics and benthic community structure. Exploring such interactions opens new perspectives on how microparasites may influence ecosystem functioning, not only through physiological disturbances but also via changes in host functional traits.
(Journal of Invertebrate Pathology. vol. 217, n° 0022-2011, pp. 108605, 01/07/2026)
ECOMAP, AD2M, SU, CNRS, SBR, SU, CNRS, EDYMAR, AD2M, SU, CNRS, SBR, SU, CNRS, AD2M, SU, CNRS, SBR, SU, CNRS, SBR, SU, CNRS, CNRS, STAMAR, INSU - CNRS, SU, CNRS, ISTerre, IRD, INSU - CNRS, USMB [Université de Savoie] [Université de Chambéry], CNRS, Fédération OSUG, UGA, FR2424, SBR, SU, CNRS, UB, Bordeaux INP, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CENAREST
Continuous speleothem record from central Tunisia (the Mine cave) reveals climatic events for the last 27 ka
The Last Deglaciation, a key period punctuated by many climatic events, has been recorded in several natural archives but, it has been rarely recorded continuously on speleothems because of the presence of stops in their growth rate due to cold/dry climates. Here we present the results of a stalagmite (Min-stm2) from the Mine Cave (Oueslatia, Tunisia) that cover continuously the last 27 ka BP after a very slow growth between 120 ka to 35 ka. The time resolution, calculated with twenty-eight U/Th dating points and a 1 mm sampling space for stable isotopes, reaches 24 years during the Bølling-Allerød (BA) period, while it was the lowest (330 a/mm) during the Younger Dryas (YD). The growth rate (GR) curve reveals a sudden growth increase at 27.5 ± 0.08 ka BP, a key point in the stalagmite history, demonstrating that infiltration due to a humid and a relatively temperate climate started again at least in Tunisia. More vigorous northwesterly winds combined with the southern displacement of the ITCZ belt may explain this abrupt hydrological change. Despite of extreme cold climate that occurred N-Mediterranean area (i.e. Western Europe) during the Last Glacial Maximum (LGM) and the Oldest Dryas, the studied stalagmite kept a sustained GR showing a quite high humidity in the N-Tunisia area. The Last Deglaciation is here clearly marked by a large decrease in the calcite δ18O and δ13C between maximum values at 21.9 ka, denoting the coldest conditions, and minimum values at 8.5 ka coinciding with the warmest conditions. Even if the isotopic curves nicely mimic the ice and marine core records of the deglaciation, detailed events show some noticeable differences. For example, the stalagmite δ13C at the end of the BA is interrupted by a rapid and pronounced isotopic increase denoting colder conditions after 13.3 ± 0.1 ka BP which could be related to the IACP (Intra Allerød Cold Period). GR during the YD appears extremely slow. The Holocene onset, at about 11.7 ± 0.09 a BP, is marked by a gradual decrease in δ18O and δ13C until 8.3 ka associated with high GR suggesting increased precipitation. Despite the high time resolution during this period (better than 40 years), the 8.2 ka event is not recorded, marking a different sensitivity compared with more western and northern speleothem records. While the δ18O continuously increased after the Holocene optimum at 8.3 ka, a positive excursion occurred on the δ13C between 8.3 ka and 6.3 ka suggesting a reduction in the vegetation activity. This is likely due to increased seasonality with drier spring/summer conditions and humid autumn/winter and/or lower CO2 dissolution in the soil water during infiltration. The comparison with a former studied stalagmite from the same cave brings precious information about the local influences in recording detailed climatic variations.
(Quaternary Science Reviews. vol. 384, n° 0277-3791, pp. 109921, 01/07/2026)
LMRE, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, UTM, PALEOCEAN, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, IGEC, Xjtu, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, UNIROUEN, NU, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Vegetation Increases CH4 Emissions and Methanotroph Diversity in Marine Sediments
Seagrass meadows are key blue carbon (C) ecosystems, storing large amounts of organic C over centuries. Their climate benefits may be reduced by methane (CH 4 ) emissions, whose microbial and environmental descriptors in Zostera noltii meadows, dominant seagrass in North‐Western Europe, remain poorly understood. We studied CH 4 fluxes, CH 4 ‐producing and consuming microbial communities and sediment physicochemical parameters in Z. noltii meadows and adjacent bare sediments across seven sites in Arcachon Bay, France. In situ CH 4 fluxes were measured at low tide during daytime conditions, providing standardized estimates of peak emissions. Microbial communities were characterized using targeted metagenomics of three functional genes ( mcrA , mmoX , pmoA ) and quantitative PCR. CH 4 fluxes were higher in vegetated than bare sediments (24.4 ± 2.6 vs. 9.4 ± 0.7 μmol m −2 day −1 ). Mixed linear models and random forest analyses identified C accumulation rate and CO 2 flux as the strongest positive descriptors of CH 4 fluxes. Vegetated sediments hosted more diverse methanotrophs, while methanogens showed no habitat differences. Four genera ( mcrA–Methanolobus , mmoX–Methylocella , pmoA–Methylococcus , Methyloglobulus ) emerged as abundant, seagrass‐associated, correlated with CH 4 fluxes, and highlighted by models. Functional diversity, especially pmoA richness, was a stronger microbial descriptor of CH 4 fluxes than gene abundance or a specific genus. Findings indicate Z. noltii meadows enhance C burial and CH 4 emission, with methanotroph diversity potentially mitigating CH 4 emissions. Our results provide the first integrated assessment of CH 4 fluxes and their descriptors in Z. noltii meadows, based on limited temporal coverage capturing the daytime peak emission conditions, highlighting the intertwined nature of C burial and CH 4 emissions and the need to account for both in blue C climate assessments.
(Global Change Biology. vol. 32, n° 1354-1013, pp. e70989, 01/07/2026)
LEM, UCBL, ENVL, VAS, CNRS, INRAE, CEAB, CSIC, UEF, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, Bordeaux INP, IFPEN, OASU, UB, INSU - CNRS, ULR, CNRS, INRAE, UMR Eco&Sols, Cirad, IRD, INRAE, Institut Agro, UM, UNIMI
DroneSCAT: A Drone-Borne and Low-Cost Microwave Scatterometer for Subsurface Imaging
Using low cost and commercial elements, we designed and realized a drone-borne microwave scatterometer in the 1-6 GHz range for subsurface imaging applications. The core of the instrument of a portable vector network analyzer associated to lightweight horn antennas produced using 3D printing. It is carried by DJI drones and accurate positioning is performed with the help of the free Centipede GNSS system. We validated our DroneSCAT instrument over a coastal parabolic sand dune, allowing the detection of buried paleosols down to 3 meters. We then tested it for archeological prospecting and detect a strong reflector buried 1 meter deep. The DroneSCAT instrument allows the detection of subsurface structures, with the benefit of a very agile system and without need for contact with the ground.
(Drone Systems and Applications. vol. 14, n° 2564-4939, 25/06/2026)
OASU, UB, INSU - CNRS, ULR, CNRS, INRAE, LAB, UB, INSU - CNRS, CNRS, PACEA, UB, CNRS, UBM, CNRS, UB, UBM, CNRS, UB, UBM, CNRS, CNRS, UBM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS