Cet article propose une première exploitation d'une base de données massives visant à décrire l’occupation de l’espace maritime par les navires marchands dans la Caraïbe. Cette occupation est résolument polymorphe du fait des activités maritimes et des types de navires qui y participent. Pour rendre compte de la diversité des géographies qui en découlent, nos travaux reposent sur une analyse désagrégée rendue possible grâce aux données de surveillance du trafic maritime AIS (Automatic Identification System). En développant une base de données multi-sources intégrant des données AIS couplées à des bases d’identification des navires et de caractérisation des terminaux portuaires, nous avons pu analyser les trajectoires maritimes des navires au cours d’une année entière et à l’échelle de la Grande Région Caraïbe pour en restituer les principales routes et escales. Les résultats de cette analyse exploratoire mettent en lumière la variabilité de l’emprise spatiale du transport maritime selon la nature des marchandises transportées (vrac sec ou liquide, conteneurs, passagers de croisière ou inter-îles, navires de service). Cette base de données se révèle donc être un outil précieux pour mieux appréhender les pressions environnementales générées par les différentes filières du transport maritime, en mer, le long des côtes et dans les zones portuaires, sur les écosystèmes, les territoires riverains et leur population.

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Cet article vise à analyser la publicisation des débats sur les orientations de politiques publiques, les choix sociotechniques et les solutions alternatives avancés par des acteurs et actrices, pour faire face aux situations de sécheresse et de pénurie en eau. Il prend pour cas d’étude l’État d’Arizona (États-Unis), dans lequel ces situations se multiplient et s’intensifient. Les analyses combinent les connaissances apportées par des entretiens et des observations sur le terrain avec l’analyse des réseaux d’acteurs et actrices, des discours collectés dans la presse locale et des messages sur Twitter. Il apparaît que les prises de position et les décisions de nature politique et économique entraînent des conséquences déterminantes sur la répartition des ressources hydriques. Enfin, l’article montre comment les prises de position et les discours, en relation avec les enquêtes de terrain, représentent une source d’importance pour évaluer les configurations spatio-temporelles des épisodes de sécheresses et pour déterminer quels sont les risques et les mesures mises ou à mettre en œuvre qui préoccupent les sociétés et font l’objet de débats publics.

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This article explores the process of implementing an interdisciplinary and participatory scientific approach in the “OHM Pays de Bitche” (Pays de Bitche Human-Environment Observatory).

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Urban pavements, which help to maintain clean and secure streets, generate large amounts of runoff that aggravate flooding and degrade the quality of surface water. In the context of ecological and climatic crisis, they also contribute to the creation of heat islands in cities, as well as hindering biodiversity. So greening cities must be encouraged. Our article highlights the case of Montpellier - Mediterranean Metropolis (Montpellier 3M, Southern France), which is undergoing one of the highest rates of demographic and urban growth in France. It asks questions around the impact of increased construction on the quality of water in small and fragile coastal catchment areas by the Mediterranean. It also examines local collective action in an attempt to identify the brakes and levers on greening initiatives for the effective management of runoff water, encouraged by legislation: de -paving, setting up rain gardens and returning to permeable urban soils. We use empirical material collected during sociological research in addition to hydrological and chemical measurements. Our aim was to elucidate the perspectives of a wide range of stakeholders, since an understanding of these is crucial in adapting blue-green infrastructure to the local context so that it is both efficient and accepted as a legitimate solution. Our examination suggests ways to think democratically about the dismantling of bitumen road paving to slow down urban water flows and thus improve the habitability of Southern European cities in a context of climatic and ecological crisis.

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Abstract Self-sustaining vegetation in metal-contaminated areas is essential for rebuilding ecological resilience and community stability in degraded lands. Metal-tolerant plants originating from contaminated post-mining areas may hold the key to successful plant establishment and growth. Yet, little is known about the impact of metal toxicity on reproductive strategies, metal accumulation, and allocation patterns at the seed stage. Our research focused on the metal tolerant Atriplex lentiformis. Specifically, we examined the effects of toxic metal(loid) concentration in soils on variability in its reproductive strategies, including germination patterns, elemental uptake, and allocation within the seeds. We employed advanced imaging techniques like synchrotron X-ray fluorescence microscopy (2D scans and 3D tomograms) combined with inductively coupled plasma mass spectrometry to reveal significant differences in metal(loid) concentration and distribution within the seed structures of A. lentiformis from contrasting habitats. Exclusive Zn hotspots of high concentrations were found in the seeds of the metallicolous accession, primarily in the sensitive tissues of shoot apical meristems and root zones of the seed embryos. Our findings offer novel insights into phenotypic variability and metal tolerance and accumulation in plants from extreme environments. This knowledge can be applied to enhance plant survival and performance in land restoration efforts.

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Although global plastic distribution is at the heart of 21st century environmental concerns, little information is available concerning how organic plastic additives contaminate freshwater sediments, which are often subject to strong anthropogenic pressure. Here, sediment core samples were collected in the Rhone and the Rhine watersheds (France), dated using 137Cs and 210Pbxs methods and analysed for nine phthalates (PAEs) and seven organophosphate esters (OPEs). The distribution of these organic contaminants was used to establish a chronological archive of plastic additive pollution from 1860 (Rhine) and 1930 (Rhone) until today. Sediment grain size and parameters related to organic matter (OM) were also measured as potential factors that may affect the temporal distribution of OPEs and PAEs in sediments. Our results show that OPE and PAE levels increased continuously in Rhone and Rhine sediments since the first records. In both rivers, ∑PAEs levels (from 9.1 ± 1.7 to 487.3 ± 27.0 ng g−1 dry weight (dw) ± standard deviation and from 4.6 ± 1.3 to 65.2 ± 11.2 ng g−1 dw, for the Rhine and the Rhone rivers, respectively) were higher than ∑OPEs levels (from 0.1 ± 0.1 to 79.1 ± 13.7 ng g−1 dw and from 0.6 ± 0.1 to 17.8 ± 2.3 ng g−1 dw, for Rhine and Rhone rivers, respectively). In both rivers, di(2-ethylhexyl) phthalate (DEHP) was the most abundant PAE, followed by diisobutyl phthalate (DiBP), while tris (2-chloroisopropyl) phosphate (TCPP) was the most abundant OPE. No relationship was found between granulometry and additives concentrations, while organic matter helps explain the vertical distribution of PAEs and OPEs in the sediment cores. This study thus establishes a temporal trajectory of PAEs and OPEs contents over the last decades, leading to a better understanding of historical pollution in these two Western European rivers.

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The quantification of microplastic (MP) pollution in rivers is often constrained by a lack of historical data on a multi-decadal scale, which hinders the evaluation of public policies. In this study, MP contents and trends were analyzed in dated sediment cores sampled upstream and downstream of a large metropolis, in environmental deposits that exhibited consistent sedimentation patterns from the 1980s to 2021. After a thorough sedimen- tological analysis, MPs were quantified in samples by micro Fourier Transform InfraRed spectroscopy (μFTIR imaging) and a density separation and organic matter digestion procedure. Microplastics recorded in the up- stream core are relatively ubiquitous all along the dated sequence. The results also confirmed a sever increase of microplastics levels in the downstream core, by one order of magnitude, and an increase of polymer types. Polypropylene, polyethylene, and polystyrene represent ubiquitous contamination and were predominant at the two stations, whereas polyvinyl chloride and polytetrafluoroethylene were suspected to be abundant at the downstream station, but were not detected at the upstream station. Their presence could be linked to local contamination from specific industrial sources that manufactured and utilized these polymers. Surprisingly, in the downstream station sediment has recorded a relative improvement in polymers associated with industrial sources since the 2000s and, to a lesser extent, for ubiquitous ones since the 2010s. This trend of mitigation diverges from that of global assessments, that assume uncontrolled MP pollution, and suggest that European Union wastewater policy and regulation on industrial discharges have positively influenced water quality, and certainly also on MPs. However, the accumulation of microplastics remains high in recent deposits and raises the emerging concern of the long-term management of these reservoirs.

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