HAL-BRGM, les publications scientifiques en libre accès du BRGM
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Overcoming barriers to youth economic inclusion in rural Morocco: A case study of Daït Aoua
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/611833/) * Autres projets (id;sigle;titre): 101084647;NATAE;(EU) Fostering agroecology transition in North Africa through multi-actor, evaluation, and networking//International audienceIn rural areas like the Daït Aoua territory, young people often face economic marginalization due to limited access to land, financial resources, and socio-cultural constraints. This study examines the economic inclusion of youth in this region and identifies key factors influencing their participation in local economies. Using a participatory territorial approach, we combined quantitative and qualitative data through surveys, interviews, and statistical analyses. The findings highlight significant spatial inequalities restricting youth to low-income, precarious roles in agricultural labor or unpaid family work, primarily due to delayed intergenerational land transfers. Despite some efforts toward income diversification through entrepreneurship and seasonal migration, these strategies are often hindered by a lack of capital and market limitations. The research underscores the need for targeted policies to address these structural barriers, promote equitable access to resources, and foster sustainable economic development. Understanding these dynamics is essential for creating opportunities that empower rural youth, enabling them to contribute meaningfully to their communities' growth
Redox gradient shapes the chemical composition of peatland microbial communities
No full textInternational audienceThe response of soil carbon to climate change and anthropogenic forcing depends on the relationship between the physicochemical variables of the environment and microbial communities. In anoxic soils that store large amounts of organic carbon, it can be hypothesized that the low amount of catabolic energy available leads microbial organisms to minimize the energy costs of biosynthesis, which may shape the composition of microbial communities. To test this hypothesis, thermodynamic modeling was used to assess the link between redox gradients in the ombrotrophic peatland of the Marcell Experimental Forest (Minnesota, USA) and the chemical and taxonomic composition of microbial communities.The average amino acid composition of community-level proteins, called hereafter model proteins, was calculated from shotgun metagenomic sequencing. The carbon oxidation state of model proteins decreases linearly from -0.14 at 10 cm depth to -0.17 at 150 cm depth. Calculating equilibrium activities of model proteins for a wide range of chemical conditions allows identifying the redox potential of maximum chemical activity. Consistent with redox measurements across peat soils, this model Eh decreases logarithmically from an average value of 300 mV at 10 cm depth, close to the stability domain of goethite relative to Fe2+, to an average value of -200 mV at 150 cm, within the stability domain of CH4 relative to CO2. The correlation identified between the taxonomic abundance and the carbon oxidation state of model proteins enables predicting the evolution of taxonomic abundance as a function of model Eh. The model taxonomic abundance is consistent with the measured gene and taxonomic abundance, which evolves from aerobic bacteria at the surface including Acidobacteria, Proteobacteria, and Verrumicrobia, to anaerobes at depth dominated by Crenarchaeota.These results indicate that the thermodynamic forcing imposed by redox gradient across peat soils shapes both the chemical and taxonomic composition of microbial communities. By providing a mechanistic understanding of the relationship between microbial community and environmental conditions, this work sheds new light on the mechanisms that govern soil microbial life and opens up prospects for predicting geochemical and microbial evolution in changing environments
Refuges thermiques en rivières dépendants des eaux souterraines : surveillance et analyse
No full textInternational audienceThermal anomalies in rivers constitute refuge for significant aquatic biodiversity, particularly during the summer. In rivers, groundwater inflows are one of the main factors in thermal anomalies. Consequently, studying the interactions between groundwater and rivers in these specific areas is a subject of major interest in assessing the vulnerability of thermal refuges to climate change. Three thermal refuges in the Rhône Mediterranee Corsica basin were selected and monitored for thermal measurements in different hydrological and hydrogeological contexts: (i) the Argens river in a Mediterranean context with the presence of a karst spring, (ii) the braided Drac river in a mountainous context interacting with a moraine aquifer and (iii) the Veyle river in a classic sedimentary context. The initial results highlight the role of groundwater in regulating surface water temperature by analysing the relationship between water temperature and air temperature. The next step is to characterise the thermal impact of groundwater as a function of the conditions in which it emerges and the riverbed and riverbanks characteristics (vegetation, size and orientation of the riverbed, etc). Finally, these results will be used to calibrate a simulation model of the impact of climate change on such thermal refuges.Les anomalies thermiques en rivières constituent des lieux de refuge pour une biodiversité aquatique importante, notamment durant les étés. En rivière, les arrivées d’eau souterraine constituent l’un des principaux facteurs d’anomalie thermique. Dès lors, l’étude des interactions entre nappes et rivières dans ces zones spécifiques constitue un sujet d’intérêt majeur dans le cadre de l’évaluation de la vulnérabilité des refuges thermiques au changement climatique. Trois refuges thermiques du bassin Rhône Méditerranée Corse ont été sélectionnés et instrumentés pour des mesures thermiques dans des contextes hydrologiques et hydrogéologiques différents : (i) l’Argens en contexte méditerranéen avec la présence de source karstique, (ii) la rivière en tresse Drac en contexte montagneux en interaction avec un aquifère glaciaire et (iii) la rivière Veyle dans un contexte sédimentaire classique. Les premiers résultats permettent de mettre en évidence le rôle de l’eau souterraine dans la régulation de la température de l’eau de surface grâce à l’analyse des relations entre la température de l’eau et celle de l’air. La prochaine étape consiste à caractériser l’impact thermique des eaux souterraines en fonction de leurs conditions d’émergence et des facteurs d’aménagement de la rivière (ripisylve, taille et orientation du lit, etc). Finalement, ces résultats seront utilisés pour calibrer un modèle de simulation de l’impact du changement climatique sur ces refuges thermiques
Le laboratoire Audois Talanoa : une démarche participative pour une adaptation transformative des usages de l’eau face au changement climatique
No full textInternational audienceIn the Mediterranean region, climate change is considerably increasing the water requirements of crops, while water resources are becoming scarcer due to reduced and altered rainfall patterns, leading to more frequent and intense water crises. The Talanoa-Water project proposes to respond by combining dialogue between stakeholders to collectively develop transformative adaptation strategies, and modelling to assess the performance of these strategies. This experiment was carried out on the Aude Médiane et Aval, one of the most overexploited river basins in France. The co-construction of strategies for adapting the agricultural sector and water management to climate change was based on a series of participatory workshops involving more than a hundred participants representing the various stakeholders. They first drew up prospective scenarios for changes in the local economy, agricultural development and water use for four contexts based on socio-economic trajectories (SSPs). They then proposed adaptation strategies in the form of action packages for these different contexts. They also played an active part in developing the model representing hydrological, agronomic and economic dynamics, which is responsible for assessing the performance of the adaptation strategies proposed by the stakeholders. The dynamics of the stakeholders and the results of the ‘Audois’ laboratory are now widely re-used in the context of the Aude basin's PTGE.Dans la région méditerranéenne, le changement climatique augmente considérablement les besoins en eau des cultures, tandis que les ressources en eau se raréfient en raison de la réduction et de la modification des régimes pluviométriques entraînant des crises de l’eau plus fréquentes et intenses. Le projet Talanoa-Water propose d’y répondre en combinant le dialogue entre les parties prenantes pour faire émerger collectivement des stratégies d’adaptation transformatives, et une modélisation permettant d’évaluer la performance de ces stratégies. Cette expérience a été notamment menée sur l’Aude Médiane et Aval, l'un des bassins hydrographiques les plus surexploités de France. La co-construction de stratégies d'adaptation du secteur agricole et de la gestion de l'eau au changement climatique s’est faite autour d’une séries d’ateliers participatifs engageant plus d’une centaine de participants représentants les différentes parties prenantes. Elles ont d’abord élaboré des scénarios prospectifs d’évolution de l'économie locale, du développement agricole, des usages de l’eau pour quatre contextes issues de trajectoires socio-économiques (SSP). Elles ont ensuite été amenées à proposer des stratégies d’adaptations déclinées en paquets d’actions pour ces différents contextes. Elles ont aussi activement participé à l’élaboration du modèle représentant les dynamiques hydrologiques, agronomique et économique et chargé d’évaluer la performance des stratégies d’adaptation proposées par les acteurs. La dynamique d’acteurs et les résultats du laboratoire « Audois » sont désormais largement réutilisés dans le cadre du PTGE du bassin de l’Aude
Addressing Socio-Economic and Environmental Challenges Linked to Water Temperatures in the Face of Global Change : Application at the Seine Hydrosystem
No full textInternational audienceTemperature is a critical factor at the interface between water and energy stakeholders. It plays a vital role in enabling them to sustain and develop their activities without competing for resources, particularly during periods of crisis. Both surface water bodies and subsurface compartments (<200 m), essential for maintaining aquatic ecosystems and supporting human adaptation to global changes, are utilized for a range of purposes. These include low-impact thermal energy production (e.g., river uses and shallow geothermal energy), drinking water supply, irrigation, and industrial applications.However, these diverse uses by water and energy stakeholders, along with their associated infrastructures, lead to thermal interferences. These interferences are superimposed on broader climatic variations and trends, further complicating resource management.In the Seine basin, observed trends are projected to persist and intensify. These include rising average temperatures, decreasing summer rainfall, and the increasing frequency and severity of extreme events such as floods, droughts, and heatwaves. The sustainable management of water resources will hinge on our collective ability to anticipate and mitigate the effects of these changes.To better predict the Seine basin’s responses to climate change, it is crucial to deepen our understanding of heat transfers between the atmosphere and the various compartments of the hydrosystem. This knowledge will be key to developing strategies that balance the needs of all stakeholders while preserving vital ecosystems and ensuring resilience against global change.In this presentation, we will present data collection, the development of numerocal tools, and the evaluation of the evolution of the Seine's temperatures over 100 years. Physical models and simulations help quantify thermal fluxes, highlighting the main sources of heat input and heat losses. The use of machine learning models in projecting the Seine's temperatures in Paris by 2100 adds a predictive dimension. Future developments to achieve modeling that allows us to produce numerical simulations necessary for the integrated management of surface and groundwater in quantitative, qualitative, and thermal terms will be presented
Study of pharmaceuticals molecules adsorption on soils and activated carbons elaborated from agricultural residues
No full textInternational audienceWater monitoring evidence the presence in the different water bodies of several organic emerging pollutants (OEP), some of them being ubiquitous, persistent, biologically active nature, and for certain endocrine disruptors. Their occurrence may be related to the insufficient reduction of some pollutant from wastewater treatment plants (WWTP). There is thus a growing need to develop innovative and more efficient eco-processes to reduce OEP concentrations all the more since the effluent of WWTP can be used for irrigation or watering municipal garden. This process called “water reuse”, permits to limit the use of potable water for irrigation. In the BIOSEPUR project, funded by the Centre-Val de Loire region, we aim at developing innovative wastewater treatment solutions from agricultural plant waste in order to reduce the concentration some OEP, and to assess the impact of water reuse on the soil and receiving underground water on the other hand. The analysis of treated waste water from the studied WWTP highlighted the presence of 11 EOP with concentrations greater than 0.1µg/L each. The molecules were mainly pharmaceuticals (such as carbamazepine, oxazepam, diclofenac, atenolol, sulfamethoxazole) but also industrial molecules (such as benzotriazole and tolyltriazole) and AMPA, that is both a degradation product of the pesticide glyphosate and of organic phosphonates used in laundry detergents. We studied the sorption of Benzotriazole (BZT) and atenolol (ATN) on 2 soils (sand and sandy clay) sampled in a municipal garden effectively irrigated using treated wastewater by the mean of adsorption isotherms. For our tests, we weighted 20 g of soil and 20 mL of liquid containing increasing concentrations of the targeted molecule, all other conditions being identical otherwise. Sorption capacity of the 2 soils sampled were different, sorption being higher on the sandy soil. The BS soil showed a greater adsorption capacity than the PP soil for both molecules. The adsorption of ATN on both soils was higher on both types than those of BZT. In parallel of this study, agricultural residues (rapeseed straw, flax and swichtgrass) were transformed into activated carbons (AC) in the context of biomass valorization. Adsorption kinetics and isotherms of carbamazepine and sulfamethoxazole were carried out to estimate the adsorption capacity of these ACs. The next step in the study is to install a column of AC from agricultural residues in the wastewater treatment plant and make the link with what can be observed in soils
Les professions autour de l'adaptation face aux inondations: Contribution aux actions 2024
No full textDans le cadre du Groupe de Travail national sur l’Analyse Multi-Critères (GT AMC) des projets de gestion des inondations, ce rapport présente une étude menée auprès des professionnels exerçant autour de la mise en œuvre de la réduction de la vulnérabilité face aux inondations. La politique nationale de réduction de la vulnérabilité face aux inondations en France peut être mise en œuvre, de façon opérationnelle, dans le cadre de l’axe 5 des Programmes d’Action et de Prévention des Inondations (PAPI). Ces programmes ne font pas, actuellement, l’objet d’une obligation d’évaluation économique contrairement aux programmes de protection ou de ralentissement des écoulements prévus aux axes 6 et 7 des PAPI. De façon opérationnelle, la mise en œuvre des mesures de réduction de la vulnérabilité dans le cadre des PAPI se confrontent à différents points de blocages. En particulier, la question de l’efficacité et de l’efficience de ces mesures reste peu documentée. L’enjeu de notre étude est de contribuer à améliorer la connaissance autour de la fabrication, de l’installation et de l’entretien de ces mesures à travers la perspective des professions impliquées dans la mise en place de ces mesures
Geogenic greenhouse gas emissions and shale weathering: lessons learned from an alpine “eternal flame”
No full textInternational audienceNatural hydrocarbon gas seeps have been reported over a wide range of geological settings, and their contribution to atmospheric concentrations of potent greenhouse gases (CO2, CH4) may be considerable. Potential gas sources in sedimentary environments include organic-rich source rocks such as peats, coalbeds, and shale clays. The origins of natural methane seepages occurring in the French Subalpine Chains are poorly constrained and only little information is available on the mechanisms behind the gas release by weathering of organic-rich shales, notably when overprinted by recent tectonism. The investigated site, where outcropping Callovian-Oxfordian black shales emit methane, higher alkanes and CO2 through macro- and micro-seeps, shows the complexity of these mechanisms. We report geochemical, isotopic and petrographic data from the Meylan-Rochasson eternal flame site, from in-situ measurements, gas, pore water and sediment sampling and degassing experiments, and propose a conceptual model covering all stages of reservoir evolution from early diagenesis to exhumation and weathering. Rock degassing experiments under helium allowed extracting alkanes and CO2 dissolved in pore waters. Isotopic signatures from below 20–40 cm are comparable to the macro-seep, indicating a common thermogenic origin of alkanes through maturation of organic matter at ∼150 °C. Secondary methane oxidation processes affect both point- and diffuse emissions of thermogenic methane. In the pore waters of outcropping shales and colluvium thermogenic gas mix with a microbial methane component. This superposition of weathering, oxidation of OM and microbially driven processes needs to be considered in future studies investigating the importance of direct natural gas emission from shales worldwid
Geochemical fingerprinting of permanent magnet along the value chain using high precision Nd isotopic analysis
No full textInternational audienceThe transition towards a carbon-neutral economy may drastically increase our dependence on metals [1]. Permanent magnets play an important role in this transition, as they are intensively used in wind turbine generators and electric vehicles [2]. The rare earth supply chain involves more than a hundred actors and keep track of the material during the different steps of production is a real challenge. Many initiatives have been taken in order to bring more transparency in the complex network of the permanent magnet supply chain, but the actual certification methods suffer from a lack of reliable control over the different data collected. The MaDiTraCe project funded by the European Union aims at developing high performance analytical methods for critical raw material traceability. The present work focuses on Nd isotopic analysis as a geochemical tool for the traceability of permanent magnets. The objective of this study is to investigate whether the initial Nd isotopic composition of the rare earth ore is preserved throughout the different steps of magnet manufacturing, by measuring samples from the entire value chain. Rare earth ores, targeted ores and concentrates from all over the world were collected, as well as permanent magnets. Metallic samples from the value chain were provided by the Permanent Magnet Platform (CEA, Grenoble, France). Isotopic analyses were performed using both MC-ICP-MS (Ghent University, A&MS group, Belgium) and TIMS (BRGM, France) for inter-lab cross-validation. Several isolation protocols were tested and optimized in order to be able to address the complex variety of the different samples. The isotope ratio obtained using TIMS and MC-ICP-MS are very close to each other, validating the two approaches for accurate and precise isotopic analysis. The eight magnet samples display an average ɛ 143Nd of – 18.50 (±0.79, 2sd). The results for the value chain samples don’t show significant isotopic fractionation between the samples, suggesting that no isotopic fractionation occurs during magnet manufacturing, despite the complex metallurgical processes involved. These results provide new insights into Nd isotopic analysis as a possible tool for permanent magnet source tracking
Identifying solutions to face groundwater overexploitation and degradation: A policy design experiment in Tunisia
No full textInternational audienceGroundwater plays an important role in achieving sustainable development goals, particularly in the Maghreb. There, groundwater management policies have been unable to stop groundwater degradation and overexploitation. In this context, it is urgent to propose concrete methodologies allowing local stakeholders to identify solutions that (1) take into account water issues but also energy and food production (i.e. solutions that are "bundled"); (2) are innovative; and (3) create a sense of collective belonging among participants. This article analyses to what extent the P-KCP method, derived from policy design, can tackle this challenge. P-KCP was used in the Lymaoua area in Tunisia. The article analyses the 39 solutions identified by Lymaoua participants and discusses the limitations and lessons learnt from this experiment. These concern the choice of the geographical area, farmers' engagement, gender representation and the use of models. The conclusion includes recommendations for coupling P-KCP with participatory planning to detail how the solutions can be concretely implemented and monitored, as well as the governance arrangements needed. Another recommendation is to expand the scope of collective groundwater organizations to encompass energy, agricultural production, land use, social equity and ecosystem preservation issues. Finally, avenues for future research are suggested