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Kinematic inventory of rock glaciers in the Pyrenees based on InSAR and airborne LiDAR data
No full textInternational audienceRock glaciers (RGs) are ice and debris landforms shaped by long-term permafrost creep. Their inventory has expanded significantly in the past two decades due to their importance as water resources and indicators of climate change. Previous inventories in the Pyrenees are sparse and lack essential kinematic data, leading to an underestimation of active RGs. This study presents the first kinematic database of Pyrenean RGs, integrating European Ground Motion Service (EGMS) InSAR data with airborne Laser Imaging Detection and Ranging (LiDAR) datasets and seven years of Sentinel-1 high-resolution InSAR data processed by the SqueeSAR algorithm. The analysis focuses on three igneous plutons (Panticosa, Cauterets, and Neouvielle) in the central Pyrenees, comparing surface displacement rates from these techniques to previous geodetic measurements. A total of 733 RGs have been mapped in the Pyrenees, covering an area of 58.9 km 2 . 73 % of the mapped RGs are inactive or relict, showing no ground displacement and being partially vegetated. Only 13 % (96 RGs) remain active, covering less than 10 km 2 , and are primarily north-facing. An additional 14 % (102 RGs) lack InSAR data but they are considered potentially active based on their orientation, altitude, and remarkable morphological features. The existence of active RGs at relatively low altitudes lowers the permafrost boundary between 2100 and 2600 m on north-and south-facing slopes, respectively. Despite the limitations of InSAR to measure displacements along the north-south axis and the fact that most active RGS are oriented to the north, according to the decomposition of the LOS displacement to vertical and horizontal components and LiDAR data, the ongoing subsidence and decline in horizontal movement related to ice degradation suggest a transition of many RGs from active to relict, marking rapid permafrost degradation. Finally, the EGMS has proven inadequate for detecting slow-moving active RGs in the Pyrenees due to temporal decorrelation caused by prolonged snow cover periods, particularly when compared to the combined use of SqueeSAR and airborne LiDAR datasets. The EGMS detected ground information for only 14 out of 89 active RGs, provided inaccurate kinematic data and underestimated the decomposed vertical and horizontal velocities by up to fourfol
Two species, two stories: divergent morphometric evolution of sheep and goats over the last 8000 years
No full textInternational audienceSince their domestication about 10 500 years ago, sheep and goats have been central to human subsistence economies. Despite shared traits and frequent co-herding, these species are biologically distinct, with their uses reflecting diverse cultural practices. Advances in geometric morphometrics enable detailed analyses of their phenotypic evolution, shaped by natural and artificial selection, genetic drift and gene flow. These evolutionary mechanisms are often challenging to disentangle in archaeozoology, but patterns of morphometric variation can reveal evolutionary parallels and divergences. This study investigates the morphometric evolution of sheep and goat teeth in the northwestern Mediterranean basin over 8000 years. Dental remains, which preserve well in archaeological contexts, provide rich data for evolutionary studies, including species-level identifications. Using two-dimensional geometric morphometrics, third lower molars from 1602 sheep and 635 goats, spanning archaeological and modern specimens, were analysed. Molar size, shape and variance were compared across six chrono-cultural phases, tracing diachronic morphological changes. Distinct patterns emerge: sheep exhibit greater variability likely reflecting selective breeding for diverse purposes. Goats, in contrast, show greater uniformity. These findings underscore unique evolutionary trajectories for sheep and goats, offering new perspectives on their biocultural evolution within the dynamic environmental and anthropic contexts that shaped their current diversity. This article is part of the theme issue ‘Unravelling domestication: multi-disciplinary perspectives on human and non-human relationships in the past, present and future’
Winter Storm Surge Event Long‐Term Variability in the North Atlantic
No full textInternational audienceChanges in storm surge events are investigated using the Event CHARacterization method, which identifies and quantifies the various dynamical structures of a typical storm surge event. This method was applied yearly, using a 20 year sliding window, to a set of 41 long-term tide gauges in the North Atlantic. Storm surge events were investigated on the basis of four key parameters: the amplitude and duration of two structures related to atmospheric pressure (Gaussian structure) and wind stress (Laplace structure). The analysis reveals large changes in 71% of the tide gauges, located in the eastern North Sea, the Baltic Sea, and in specific regions of North America. Changes are more important for the duration (±16%) of the events than for the amplitude (±7%). In Europe, the pressure-induced structure (Gaussian) is more affected by changes than the wind-stressinduced structure (Laplace). In addition, the changes in North America show patterns with significant linear trends that lacked discernible geographical coherence, while in Europe, the changes exhibit cyclic patterns with more obvious geographical coherence.Plain Language Summary Storm surges are caused by extreme weather systems such as storms and are responsible for coastal flooding. Considering the full dynamics of the events from 20 days before to 20 days after each maximum, most of the changes in storm surge events follow different cycles of 40-60 years, whereas only a few follow a strict linear trend. The duration of the events changes more rapidly than the amplitude of the elevation. The changes observed are quite different between the two sides of the North Atlantic. First, in North America, the changes due to the wind are more important, while in Europe, the changes due to the atmospheric pressure are more important. Second, in Europe, the pattern of the changes mostly follows cycles of 40-60 years, whereas in North America, the pattern of the changes is more linear.</div
Optimizing MDA and antimalarial treatment in the presence of drug resistance for effective malaria control
No full textInternational audienceAntimalarial drugs are critical for controlling malaria, but the emergence of drug resistance poses a significant challenge to global eradication efforts. This study explores strategies to minimize resistance prevalence and improve malaria control, particularly through the use of mass drug administration (MDA) in combination with antimalarial drugs. We develop a compartmental mathematical model that incorporates asymptomatic, paucisymptomatic, and clinical states of infection and evaluates the impact of resistance mutations on transmission dynamics. The model includes both treated and untreated states among infected and recovered individuals, with a focus on optimizing control strategies through MDA and antimalarial treatment. A global sensitivity analysis identifies the critical factors that influence malaria dynamics, including MDA coverage, treatment access for different infection states, the probability of mutation from treated sensitive human infections, to treated resistant human infections and the initial prevalence of resistance. The model is extended to include optimal control strategies that provide time-dependent control interventions for treatment and MDA. Intuitively, when the mutation rate is relatively low, the optimal strategy combines the use of antimalarial drugs and MDA, with a gradual decrease in antimalarial drug use over time, ensuring sustainable malaria control. In contrast, at higher mutation rates, the strategy prioritizes broader deployment of MDA while significantly reducing reliance on antimalarial to minimize the risk of resistance developing. Numerical simulations of the optimal control problem reinforce the importance of strategic intervention in mitigating drug resistance. This study contributes to understanding the role of MDA and treatment strategies in the control of malaria, with implications for optimizing malaria control programs in endemic regions.</div
Widespread and Exceptional Reduction in River Water Levels Across the Amazon Basin During the 2023 Extreme Drought Revealed by Satellite Altimetry and SWOT
No full textInternational audienceIn late 2023, the Amazon River Basin experienced its most extreme drought to date, putting its population and ecosystem at risk. Gauges that were still functioning measured the lowest river water levels (RWL) on record. Here, satellite observations, including Surface Water Ocean Topography (SWOT), reveal the spread and timing of extremely low RWL across the entire river system. The majority of Nadir altimeter observations show that the 2023 minimum RWL in the Central Amazon were 3 m or more below their annual average, representing two to three times its mean variability. Additionally, SWOT captures the basin-scale reduction in RWL with a spatial resolution of 200 m and how it propagates with time. Large-scale evaluation with gauges suggests that SWOT outperforms classical altimetry in estimating RWL, despites differences that need further investigations. SWOT offers a new opportunity to understand hydroclimatic extremes and their broad impacts on the environment of the Amazon
CLIMAAX - Deliverable Phase 1 – Climate risk assessment
No full textRéunion Island’s Climate Risks Atlas project (RISC-RA) aims to carry out an assessment of climate risks on Réunion Island, a French overseas territory exposed to intense natural hazards. Réunion Island’s Regional council, hereafter called Region Réunion, a local public authority in charge of sustainable development and regional planning, has been managing the project since 1st October 2024 in collaboration with a scientific research group.This deliverable presents the organization, methodology and results of the RISC-RA project at the end of the first 6 months of work. The initial climate risks assessment has prioritized two main climate hazards: Droughts and Heavy Rainfall events, each already posing substantial and growing threats to socio-economic stability, infrastructure integrity, public health, and environmental sustainability. The general CLIMAAX methodology was adapted to the local context, using high-resolution climate data and local exposure and vulnerability datasets. The first phase of RISC-RA was also devoted to setting up the team's operational organization, establishing project governanceand making initial contacts with external stakeholders.Regarding the two main risks addressed during this phase, the following observations and results can be drawn:(1) Drought Risk: Droughts on Réunion Island are slow-onset hazard Island caused by prolonged periods of below-normal rainfall. The territory experienced extreme drought in December 2024 and January 2025, the driest months recorded for over 50 years. The analysis using regional climate projections indicates an increase in both intensity and spatial extent of drought risk, particularly in the northern and northwestern regions.(2) Extreme Rainfall Risk: the island holds most world records for rainfall duration over time intervals ranging from 12 hours (1144 mm) to 15 days (6083 mm). Heavy rainfall is a sudden-onset hazard expected to intensify, with projections indicating extreme rainfall events becoming more frequent, notably affecting northern, eastern, and southern coastal regions. Historical analysis identified a threshold of approximately 220 mm/day, regularly triggering catastrophic events.Phase 1 provided significant insights into regional climate vulnerabilities and risks, particularly highlighting drought and extreme rainfall as pressing concerns. This year 2025 was a perfect example of this, with a persistent heatwave during the first’s months, a severe drought in the northeastern areas, including water unavailability and water restrictions usages. This was followed by Cyclone Garance, one of the strongest cyclones experienced in La Reunion with devastating impacts.The climate risks analysis produced during phase 1 will serve as the first version of the Risk Atlas, which will be refined and discussed with local public authorities and practitioners. The findings of deliverable no. 1 will be used as the basis for the first local workshop to present the RISC-RA projectto local stakeholders, such as the Drought Committee, for example. The preliminary results for both historical data and projection will be improved in Phase 2 with case studies for the validation of vulnerability indicators and the extended analysis of heavy rainfall. At the same time, one or two new Workflow(s) will be explored
Environmental contamination by metals, metalloids, and cyanides in the historic and active ASGM area of Kokumbo in Côte d’Ivoire
No full textInternational audienceIn Côte d’Ivoire, despite an intense development of artisanal and small-scale gold mining (ASGM) activities in thelast two decades, the environmental impacts of this activity are poorly documented. This study aimed to documentthe concentrations of geogenic and exogenous contaminants potentially released by ASGM (metals and cyanides) indifferent sources (ore, mining wastes) and environmental compartments (soils, surface and ground waters, sediments) inthe Kokumbo area, part of the Au-rich Birimian greenstone belt. Alluvial ore material is enriched in various metal(oid)s (As, Co, Cu, Cr, Fe, Mn, Ni, Sb, and V) compared to the average composition of the upper continental crust whileother metals (Cd, Pb, Ti, Zn) show no geochemical anomalies. High Hg concentrations were found in cyanidationresidues (up to 8.32 mg/kg) and sediments (up to 20.4 mg/kg) compared to unprocessed alluvial ores (0.06 ± 0.01 mg/kg) indicating that Hg used in amalgamation is the source of Hg contamination. Cyanidation residues contain up to100 mg/kg of total cyanides but generally less than 3% are in the form of free cyanides, the most mobile and toxicform. Arsenic concentrations in water are low (< 2.5 μg/L) despite its relatively high content in sediments and soils(76 ± 54 mg/kg), showing a low mobility of As, likely due to its adsorption on iron oxy(hydr)oxides. Apart from Mn,metals have low dissolved concentrations in water except in a stream draining a cyanidation site suggesting that thecyanidation effluent discharge may contribute to metal dispersion in rivers
Structure interne des incisives supérieures permanentes néandertaliennes provenant des deux phases climatiques de l’Hortus (Hérault, France)
No full textInternational audienceDans l’étude princeps sur les restes néandertaliens de l’Hortus (stade isotopique marin 3), deux groupes rattachés à des environnements différents et présentant les caractères néandertaliens attendus ont été distingués à partir des dimensions externes des couronnes. Les spécimens aux dimensions coronaires réduites pourraient être qualifiés de "méditerranéens". À partir des types de dents communes aux deux niveaux, nous souhaitons vérifier cette distinction grâce à de nouvelles analyses intégrant l’anatomie interne et situer les Néandertaliens de l’Hortus au regard de la variation néandertalienne et de celles des Hommes modernes. Cette étude porte sur les incisives supérieures de la phase IVA, froide et humide, et de la phase V, plus froide et plus aride. Notre échantillon microtomographique inclut 15 incisives supérieures de l’Hortus, 24 incisives néandertaliennes et 73 d’Hommes modernes. Nous prenons en compte les volumes coronaires et racinaires, les proportions tissulaires et les traits non-métriques à la jonction émail-dentine (JED). Nos résultats confirment le caractère typique néandertalien des dents de l’Hortus grâce à l’analyse des structures internes (e.g. émail très fin) et des traits non métriques à la JED. Les spécimens de la phase IVA ont des volumes coronaires et radiculaires généralement plus élevés que ceux de la phase V, en possédant des valeurs proches de celles des Néandertaliens. Les spécimens de la phase V ont des volumes, coronaire et radiculaire, inférieurs à la valeur minimale observée chez les Néandertaliens. Ces volumes sont proches de la moyenne des Hommes modernes pour les couronnes et supérieurs à la valeur maximale des Hommes modernes pour la racine. Dans notre contexte, il semble difficile de faire un lien de causalité entre environnement et taille des dents (ou des os) et entre proportions d’émail et chronologie puisque des dents d’émail très fin se retrouvent également à Krapina et à Scladina au stade isotopique 5
Impacts of soil storage on microbial parameters
No full textVoir aussi le preprint : Impacts of soil storage on microbial parameters, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2024-411, 2024International audienceThis review aims to determine the impact of soil storage on microbial parameters (abundance/biomass, activity and various diversity metrics). We analysed the literature dealing with the impact of storage practices (cold, freeze, dry, freeze-dry and ambient storage) on soil microbial parameters. A total of 73 articles were included in the analysis, representing 261 basic data (impact of a given storage practice on a microbial parameter). Globally, 74 % of these data showed significant impact of storage on the measured microbial parameters, as compared to those measured on fresh, nonstored soil samples. The storage practices showed various effects on the soil microbial parameters, with sometimes opposite effects across different soil types. For instance, various soil enzyme activities did not respond the same way to storage practices, even in a given soil type. There are currently too few studies to draw recommendations, but some studies suggest that the pedoclimatic context could be useful for choosing the best storage option, with soils that regularly undergo drought or freezing being less impacted by dry and freeze storage, respectively. I conclude that storage practices for soil samples, when unavoidable, should be carefully selected according to conditions that prevail in the native soil environment, to microbial parameters that are analysed (even though there is no consensus for a best practice), and with different storage practices for different microbial parameters if necessary