Conditions et temporalités de la remise en mobilité des dunes de la cote girondine
Les dunes sont des objets complexes des systèmes littoraux sableux, contrôlées par des mécanismes d’interactions multiples et non linéaires. Sur de nombreux secteurs dans le monde, et particulièrement en climat tempéré, les systèmes dunaires littoraux sont globalement stables et fixés. Néanmoins, sous certaines conditions (forçages marins et éoliens énergétiques, disponibilité sédimentaire modérée à forte, réduction du couvert végétal…) certaines dunes littorales peuvent se remobiliser. A partir d’un jeu de données constitués de Modèles Numérique de Terrain (MNT) issus de mesures LiDAR aéroportées, collectées en 2011 puis à fréquence annuelle sur près d’une décennie de 2014 à 2023, nous proposons une analyse des évolutions du cordon dunaire de la côte Girondine sur 85 km. Les résultats montrent que suite à une séquence d’érosion marine (hiver 2013-2014), le cordon dunaire a connu une mobilité importante à échelle décennale sous l’effet des flux éoliens, entrainant des réponses morphologiques variables spatialement. Ces réponses vont de la quasi-stabilité au passage de dunes fixes à transgressives le long de linéaires de plusieurs kilomètres. On observe que la remobilisation du cordon dunaire n’est pas conditionnée par la disponibilité sédimentaire, celle-ci pouvant aussi bien apparaitre en contexte de forte disponibilité que sur des sites en érosion chronique où les apports sont quasi nuls. Face aux problématiques posées par l’immobilité des cordons dunaires littoraux (i.e. réduction voire disparition des cordons bordiers), l’érosion marine potentiellement associée à des actions de gestion (écrêtage, adoucissement des pentes) peut être considérée comme une opportunité pour la remise en mobilité des dunes de front de mer.
(pp. 391-400, 24/06/2024)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ONF, CEFREM, UPVD, INSU - CNRS, CNRS
Patterns in macrobenthic diversity in the lower shore of northeastern Atlantic macrotidal sandy beaches
Although knowledge of sandy beaches has increased recently, the benthic diversity of macrotidal sandy beaches in the northeastern Atlantic Ocean (more specifically, the western Channel and the northern Bay of Biscay) is poorly known. Here, we present a regional-scale account of the species diversity, both observed and estimated, of the macrobenthic fauna of Brittany based on an analysis of a species-level data set from 18 sandy beaches in Brittany that were sampled annually for 13 yr on the lower shore. In total, 526 species were identified, including 210 Annelida, 167 Arthropoda, 103 Mollusca, 19 Echinodermata and 27 species of other phyla. Four distinct habitats were distinguished based on their benthic communities and characterised using environmental variables. Sediment heterogeneity appeared to enhance diversity, as heterogeneous muddy sand harboured significantly more species than (muddy) fine sand. The role of environmental variables as structuring factors of benthic communities was investigated using redundancy analysis and variance partitioning. Beach morphodynamics and sediment structure explained most diversity variations (25.40 and 24.91%, respectively) followed by wave characteristics (13.46%). Finally, we offer some habitat-specific reference values regarding species richness and the Shannon index for M-AMBI computation during Water Framework Directive and Marine Strategy Directive evaluations for a more reliable characterisation of the ecological status of sandy beaches.
(Marine Ecology Progress Series. vol. 738, n° 0171-8630, pp. 21-40, 20/06/2024)
IUEM, IRD, INSU - CNRS, UBO EPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, FEM, LEMAR, IRD, IFREMER, UBO EPE, CNRS
Temporal trajectories of artificial radiocaesium 137Cs in French rivers over the nuclear era reconstructed from sediment cores
137Cs is a long-lived man-made radionuclide introduced in the environment worldwide at the earlybeginning of the nuclear Era during atmospheric nuclear testing’s followed by the civil use of nuclearenergy. Atmospheric fallout deposition of this major artificial radionuclide was reconstructed atthe scale of French large river basins since 1945, and trajectories in French nuclearized rivers wereestablished using sediment coring. Our results show that 137Cs contents in sediments of the studiedrivers display a large spatial and temporal variability in response to the various anthropogenicpressures exerted on their catchment. The Loire, Rhone, and Rhine rivers were the most affected byatmospheric fallout from the global deposition from nuclear tests. Rhine and Rhone also receivedsignificant fallout from the Chernobyl accident in 1986 and recorded significant 137Cs concentrations intheir sediments over the 1970–1985 period due to the regulatory releases from the nuclear industries.The Meuse River was notably impacted in the early 1970s by industrial releases. In contrast, theSeine River display the lowest 137Cs concentrations regardless of the period. All the rivers respondedsimilarly over time to atmospheric fallout on their catchment, underlying a rather homogeneousresilience capacity of these river systems to this source of contamination.
(Scientific Reports. vol. 14, n° 2045-2322, pp. 1-16, 20/06/2024)
IRSN/PSE-ENV/STAAR/LRTA, IRSN/PSE-ENV/STAAR, IRSN, IRSN/PSE-ENV/SAME/LMRE, IRSN/PSE-ENV/SAME, IRSN, LEHNA IAPHY, LEHNA, UCBL, ENTPE, CNRS, LIVE, UNISTRA, CNRS, ITES, ENGEES, UNISTRA, INSU - CNRS, CNRS, MIO, IRD, AMU, INSU - CNRS, UTLN, CNRS, LCE, AMU, INC-CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, LOTERR, UL, GéHCO, UT, SU, METIS, EPHE, PSL, INSU - CNRS, SU, CNRS, GEGENAA, URCA, Inrap, MSH-URCA, URCA, LIEC, INSU - CNRS, UL, CNRS, LTSER-ZAM, UL, CNRS, RZA, INEE-CNRS, CNRS, IRSN/PSE-ENV/SPDR/LT2S, IRSN/PSE-ENV/SPDR, IRSN, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GEDI, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA
Estimating Contaminated Soil Volumes Using a Generative Neural Network: A Hydrocarbon Case in France
(19/06/2024)
LITIS - App, LITIS, ULH, NU, UNIROUEN, NU, INSA Rouen Normandie, INSA, NU, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
What do we know about the ecology of aquatic Isoëtes species? Data gaps and opportunities to improve the global protection of truly iconic plants
The genus Isoëtes includes iconic plants, characteristic of a wide range of ecosystems including nutrient-poor aquatic waterbodies. They are wetland obligates which have suffered severe losses globally over time mainly due to alterations and loss in colonized habitats. This is due to their sensitivity to habitat alteration and eutrophication of water and sediment. Despite this, a global review of the ecological knowledge about aquatic species belonging to this genus is missing, and overall, we know very little at the global scale. An assessment of aquatic Isoëtes ecology is therefore important, particularly for a better understanding of what the main threats to their conservation are. Through a global, collaborative initiative a first global ecological assessment focusing on aquatic Isoëtes was carried out. It includes a literature review, an extensive new database on Isoëtes distribution and growth conditions, and ecological niche analyses. We first compiled a global aquatic Isoëtes database including all known environmental data collected between 1935 to 2023 (for a total of 1880 georeferenced records). We then used ordinations to quantify ecological niches and environmental drivers for a subset of species. Both well-established findings and unexpected results emerged, opening new perspectives for the conservation of aquatic Isoëtes.
(17/06/2024)
UNIROMA, UNIPR, ROMA TRE, CEAB, CSIC, UR EABX, INRAE, ECLA, USMB [Université de Savoie] [Université de Chambéry], INRAE, OFB, RAS, ITV, BIOLOGY CENTRE CAS, BIOLOGY CENTRE CAS, CAS, IBER, UW-La Crosse, UNITUS, NIVA, UCPH, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, USC, IUCN, RSHU
Modelling the fate of the transformation products generated by the degradation of carbamazepine in various water treatment processes
(16/06/2024)
LGC, UT3, Comue de Toulouse, CNRS, Toulouse INP, Comue de Toulouse, UR REVERSAAL, INRAE, LPTC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Les effets potentiels du fluorure de sodium sur la truite arc-en-ciel
(Les cahiers de la Recherche : Santé, Environnement, Travail, n° 2264-7597, pp. 34-36, 13/06/2024)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Global aquatic Isoëtes Database (acronym GaID) as of 2024
Isoëtes are iconic but understudied wetland plants, despite having suffered severe losses globally mainly because of alterations in their habitats. We therefore provide the first global, comprehensive data set of aquatic Isoëtes and their habitats. We compiled a global database that includes all known environmental data collected from 1935 to 2023 regarding aquatic Isoëtes. This resulted in 2,179 records. The environmental data taken at Isoëtes' sampling stations varied but may include measures of water quality, water depth, and substrate composition.
(. vol. 69, 11/06/2024)
UW-La Crosse, UNIROMA, UNIPR, ROMA TRE, CEAB, CSIC, UR EABX, INRAE, ECLA, USMB [Université de Savoie] [Université de Chambéry], INRAE, OFB, RAS, ITV, BIOLOGY CENTRE CAS, BIOLOGY CENTRE CAS, CAS, IBER, UNITUS, NIVA, UCPH, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, USC, IUCN, RSHU
Molecular-scale view of the interaction of water and ice with organic species of atmospheric interest
The cryogenic techniques coupled to spectroscopies (FTIR, UV-visible, …) are powerful tools to study room temperature unstable species (reaction intermediates, unstable isomers, …). Molecules are trapped either in rare-gas matrix or on ice surface in controlled conditions. The low temperature and trapping conditions allow to explore molecular structures and interactions i.e. hydration process from complexes to aggregates and then to ice. Moreover, samples may be kept for long time period (over days) allowing multiple irradiation (selective or broad band) and heating cycles. In this presentation, we will propose two examples of studies related to aerosol of atmospheric interest: the first on the hydration process of 3 methyl-1,2,3-butanetricarboxylic acid (MBTCA), a relevant tracer compound for monoterpene SOA formation and aging processes. The second will focus on the investigation of interactions between gaseous methyl iodine (from marine, vegetation or terrestrial sources) and various water ice surfaces, emphasizing the influence of trapping sites on the bonding and photofragmentation of CH3I. Acknowledgments The authors wish to thank the ANR for financial support of the SOAPHY project (ANR-21-CE29-0031), the Région Nouvelle Aquitaine for it support of the LEVIAERO project (convention n°AAPR2022-2021-17126210) and the GDR EMIE for supporting the collaborative projects.
(10/06/2024)
ISM, UB, INC-CNRS, CNRS, PIIM, AMU, CNRS, CEQUINOR, CONICET, UNLP, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Iberian Paleoflora and Paleovegetation. Vol. III: Holocene
(07/06/2024)
IPE - CSIC, CSIC, UV, UC / UniCan, UGR, URV, ICREA, IPHES-CERCA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UAB, UMR ISEM, Cirad, EPHE, PSL, CNRS, UM