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UMR 6143 "Morphodynamique Continentale et Côtière"
Le laboratoire Morphodynamique Continentale et Côtière (M2C) est une Unité Mixte de Recherche (UMR 6143) créée en 1996. Il est rattaché au CNRS (INSU en principal et INEE en secondaire), à l’Université de Caen Normandie (UNICAEN) et à l’Université de Rouen Normandie (URN).
Les recherches du laboratoire M2C s’intéressent à la caractérisation et à la modélisation de la dynamique des processus naturels et des différents compartiments, le long du continuum TERRE-MER, à différentes échelles de temps et d’espace. Les recherches s’organisent en 3 thèmes :
Les recherches du laboratoire M2C s’intéressent à la caractérisation et à la modélisation de la dynamique des processus naturels et des différents compartiments, le long du continuum TERRE-MER, à différentes échelles de temps et d’espace. Les recherches s’organisent en 3 thèmes :
- Bassins versants
- Estuaire
- Côtier
Ces recherches sont réalisées avec une approche interdisciplinaire intégrant des chercheurs spécialisés en mécanique, géosciences, océanographie et hydrologie, microbiologie et biologie des organismes.
En raison de la réponse qu’elles constituent aux attentes des gestionnaires, collectivités et industriels, les activités que nous menons en matière de valorisation s’inscrivent dans le cadre de différentes recherches appliquées.
Nos recherches couplent la mesure in situ grâce à de nombreux équipements dédiés (voir rubrique plateaux techniques), des approches expérimentales et de modélisations numériques.
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Dernières publications
The emergence and selection of antibiotic resistance is a major public health problem worldwide. The presence of antibiotic-resistant bacteria (ARBs) in natural and anthropogenic environments threatens the sustainability of efforts to reduce resistance in human and animal populations. Here, we use mathematical modeling of the selective effect of antibiotics and contaminants on the dynamics of bacterial resistance in water to analyze longitudinal spatio-temporal data collected in hospital and urban wastewater between 2012 and 2015. Samples were collected monthly during the study period at four different sites in Haute-Savoie, France: hospital and urban wastewater, before and after water treatment plants. Three different categories of exposure variables were collected simultaneously: 1) heavy metals, 2) antibiotics and 3) surfactants for a total of 13 drugs/molecules; in parallel to the normalized abundance of 88 individual genes and mobile genetic elements, mostly conferring resistance to antibiotics. A simple hypothesis-driven model describing weekly antibiotic resistance gene (ARG) dynamics was proposed to fit the available data, assuming that normalized gene abundance is proportional to antibiotic resistant bacteria (ARB) populations in water. The detected compounds were found to influence the dynamics of 17 genes found at multiple sites. While mercury and vancomycin were associated with increased ARG and affected the dynamics of 10 and 12 identified genes respectively, surfactants antagonistically affected the dynamics of three genes. The models proposed here make it possible to analyze the relationship between the persistence of resistance genes in the aquatic environment and specific compounds associated with human activities from longitudinal data. Our analysis of French data over 2012–2015 identified mercury and vancomycin as co-selectors for some ARGs.
With about 8000 marine benthic species, the amphipod crustaceans form one of the richest animal groups of the worldwide Ocean. They have colonized a wide range of soft-and hard-bottom natural and artificial habitats extending from the intertidal to hadal zones. Moreover, they show a broad size spectrum, with numerous giant species exceeding 20 cm in length and some species smaller than 2 mm. When biofouling artificial hard surfaces, some tube-building species can form very dense populations comprising up to 100,000 individuals per square meter. Amphipods are important prey for fish and mammals. Along with cephalopod juveniles, they are also included in the trophic diet of shorebirds that consume amphipods mostly during the low tide on tidal flats. They display diel migration, which reinforces the predation by demersal fish in the suprabenthic zone just above the sea bed, as well as by pelagic fish in the water column. Despite their importance in terms of biodiversity and trophic transfer, no general overview is available on the role of benthic amphipods in marine ecosystem food webs. Various methods, including laboratory and field experiments, as well as the analysis of stomach contents and DNA extraction, have been used to identify the prey/predator trophic links. Based on an extensive literature review, this study discusses the role of marine benthic amphipods as potential food for higher trophic levels in natural and artificial hard-bottom communities created via the construction of offshore wind farms.
Assessing long-term changes in groundwater is crucial for understanding the impacts of climate change on aquifers and for managing water resources.However, long-term groundwater level (GWL) records are often scarce, limiting the understanding of historical trends and variability. In this paper, we present a deep learning approach to reconstruct GWLs up to several decades back in time using recurrent-based neural networks with wavelet pre-processing and climate reanalysis data as inputs. GWLs are reconstructed using two different reanalysis datasets with distinct spatial resolutions (ERA5: 0.25 • x 0.25 • & ERA20C: 1 • x 1 •) and monthly time resolution, and the performance of the simulations were evaluated. New insights: Long term GWL timeseries are now available for northern France, corresponding to extended versions of observational timeseries back to early 20th century. All three types of piezometric behaviours could be reconstructed reliably and consistently capture the multidecadal variability even at coarser resolutions, which is crucial for understanding long-term hydroclimatic trends and cycles. GWLs'multidecadal variability was consistent with the Atlantic multidecadal oscillation. From a synthetic experiment involving a modified long-term observational time series, we highlighted the need for longer training datasets for some lowfrequency signals. Nevertheless, our study demonstrated the potential of using DL models together with reanalysis data to extend GWL observations and improve our understanding of groundwater variability and climate interactions.
Abstract Background Major advances over the past decade in molecular ecology are providing access to soil fungal diversity in forest ecosystems worldwide, but the diverse functions and metabolic capabilities of this microbial community remain largely elusive. We conducted a field survey in montane old-growth broadleaved and conifer forests, to investigate the relationship between soil fungal diversity and functional genetic traits. To assess the extent to which variation in community composition was associated with dominant tree species (oak, spruce, and fir) and environmental variations in the old-growth forests in the Jade Dragon Snow Mountain in Yunnan Province, we applied rDNA metabarcoding. We also assessed fungal gene expression in soil using mRNA sequencing and specifically assessed the expression of genes related to organic matter decomposition and nutrient acquisition in ectomycorrhizal and saprotrophic fungi. Results Our taxonomic profiling revealed striking shifts in the composition of the saprotrophic and ectomycorrhizal guilds among the oak-, fir-, and spruce-dominated forests. The core fungal microbiome comprised only ~ 20% of the total OTUs across all soil samples, although the overlap between conifer-associated communities was substantial. In contrast, seasonality and soil layer explained only a small proportion of the variation in community structure. However, despite their highly variable taxonomic composition, fungal guilds exhibited remarkably similar functional traits for growth-related and core metabolic pathways across forest associations, suggesting ecological redundancy. However, we found that the expression profiles of genes related to polysaccharide and protein degradation and nutrient transport notably varied between and within the fungal guilds, suggesting niche adaptation. Conclusions Overall, our metatranscriptomic analyses revealed the functional potential of soil fungal communities in montane old-growth forests, including a suite of specialized genes and taxa involved in organic matter decomposition. By linking genes to ecological traits, this study provides insights into fungal adaptation strategies to biotic and environmental factors, and sheds light on the importance of understanding functional gene expression patterns in predicting ecosystem functioning.
Macrofaunal species inhabiting intertidal mudflats and performing intense bioturbation are considered as ecosystem engineers, since they profoundly influence their physical, chemical, and biological environments. Nowadays, to complete our knowledge on the effect of bioturbation processes on the surrounding environment, interdisciplinary approach is essential to unravel their complex intertwined effects on intertidal mudflats. In this study, the effects of bioturbators on sediment properties, biogeochemical variables, and microbial dynamics (microphytobenthos, bacteria and archaea) were investigated. To this end, manipulation experiments were carried out in an intertidal mudflat of the Seine Estuary (France) by revamped the abundance of the two dominant bioturbators, Scrobicularia plana and Hediste diversicolor, in winter and late summer. Results showed that the presence of H. diversicolor in winter had a significant effect, with a significant increase in bed level accretion and microbial nitrate reduction rates. In contrast, the presence of S. plana showed no significant impact on sediment properties, most likely due to a reduced bioturbating activity at low temperature. In summer, both ecosystem engineers strongly influenced their surrounding environment but with opposite effects. The intense reworking of the sediment surface by S. plana limited microbial growth and enhanced erosion processes. Conversely, the presence of H. diversicolor favoured sediment accretion and enhanced microbial growth. Overall, this interdisciplinary study confirms the importance of these two ecosystem engineers in temperate estuarine mudflats by highlighting their simultaneous and intertwined effects on the sedimentary, physicochemical, and biological features. This confirms the importance of actively considering ecosystem engineers when restoring the natural habitats of tidal flats to cope with the different vulnerability risks related to global warming (sandification of estuarine sediments, disappearance of productive mudflats, sea level rise, vulnerability to storms and erosion).
This study addresses the scarcity of evidence on the relationship between benthic communities and coarse-grained sediments in the eastern English Channel. The region's geological history contributes to its predominantly coarse sediment composition. The study employs ternary plots to visualize benthic species' preferences and tolerance for sediment types, revealing their effectiveness. Redundancy Analyses (RDA) and species-level quantile regressions explore the influence of grain size on benthic species distribution. The results indicate a moderate impact of grain size, influenced by hydrodynamics. Estuaries, particularly the Seine Estuary, significantly shape benthic species distribution. Quantile regressions underscore the varied responses of benthic communities along the grain size gradient. The study underscores the importance of considering coarse sediments, offering insights into the complex relationship between benthic communities and sediment characteristics.
There is an increasing need in assessing ecological quality and integrity of estuaries and lagoons as transitional waters. This chapter shows the most recent efforts in assessing individual biological elements (from phytoplankton to fishes), together with the integrative tools developed in different geographical areas worldwide. However, reducing multifaceted information needed to describe complex ecosystems that are naturally stressed from multiple ecosystem elements to a single color or value is a substantial challenge to marine scientists, and requires the integration of different disciplines (chemists, engineers, biologists, ecologists, physicists, hydrologists, managers, etc.), to reach agreement on the final assignment of ecological status. Hence, in the future, emphasis needs to be directed at understanding the complexities of estuarine system functioning rather than simplifying, deconstructing and scaling down the system into smaller components. Indeed, the process of deconstructing an ecosystem for study and then reconstructing it to give a holistic and weighted assessment is by far the greatest challenge in areas where there are many activities, pressures and effects. Key Points • To manage human pressures and impacts on transitional environments, legislation worldwide require methods to assess their ecological status, and here we revise the different methods. • Although methods can address individual ecosystem components (e.g., phytoplankton, macroinvertebrates, fish), inte-grative methods to assess the status under an ecosystem approach are more common in recent times. • Due to the natural variability of estuaries, sometimes distentangling the effects from human pressures and natural stress, can be difficult. • We have reviewed methods to assess the status for phytoplankton, zooplankton, macroalgae, angiosperms, macro-invertebrates, and fish. • Traditional and new methods (e.g., molecular-based methods) are reviewed. • The integration of multiple components, in different geographical areas, is presented.
Crustal heat loss processes in contexts other than mid-ocean ridge flanks are still poorly understood and described in the literature. In this work, we present 54 new surface heat flow measurements recorded along the South Balearic margin and across the Hannibal High area, in the Western Mediterranean Sea, away from spreading centres. The South Balearic margin is a narrow continental margin expressed on the seabed topography by the steep Emile Baudot Escarpment while the Hannibal High area, further south, is a presumed volcanic oceanic crust zone. Recent heat flow studies pointed out the presence of strong local thermal anomalies, imprinted in regional deep basin heat flow increasing from the eastern to the western Algerian basins (70-90 to 100-130 mW/m<SUP>2</SUP>). The new data in this study confirm local anomalies around the Emile Baudot seamounts and allow the delineation of some low and high heat zones. We show that (1) a correlation exists between the heat flow variability and the sedimentary cover thickness, and (2) the most pronounced anomaly is a low heat flow zone (30 km wide) observed in the mid-slope South Formentera basin, close to the basaltic basement of the Los Martines volcano. The correlation of heat flow with sedimentary thickness, the lateral extent of the heat flow anomalies, the flux peak magnitudes, and the co-existence of both low and high anomalies suggest the presence of an active fluid circulation system. Based on the arrangement of the anomalies in relation to the basaltic basement seamounts, we consider a syphon-type circulation system in the Formentera basin. Reduced heat flow suggests a recharge zone close to the Los Martines seamount, while local high heat flow located close to a smaller seamount could be a potential zone of fluid discharge. Although different buoyancy-driven circulations could occur in the South Balearic margin, we believe that a syphon-type hydrothermal circulation along permeable basaltic mounds and sealed basement conduits, similar to the off-axis oceanic crust, is best developed in the young marginal basin of the South Balearic margin.
Mots-Clés
Carbonates
Pleistocene
Marine renewable energy
English Channel
Climate change
Sahel
Introduced species
Canal à houle
Climate
Manche
Quaternary
Geomorphology
Modélisation
Morphodynamics
Mediterranean
Climate variability
Morphodynamique
Bassin versant
GIS
Benthic macrofauna
Washover
Offshore wind farm
Antibiotic resistance
Marine terrace
Hydrogeophysics
Dredged sediments
Erosion
Stratigraphie
Turbulence
Sediment
Géomorphologie
Normandie
Niger
Inverse problem
SEDIMENT
Numerical modeling
Contamination
Escherichia coli
Benthos
Stratigraphy
Physical modelling
Inversion
Non-indigenous species
Ecopath model
Coastal barrier
ACL
Holocene
Granulométrie
Numerical modelling
Sedimentology
Hydrology
Normandy
NAO
Sampling strategy
Senegal
Chemometrics
Sédimentologie
Anthropogenic impact
Biomass
Eastern English Channel
Biodiversity
France
Hyperspectral imaging
Bacteria
Ecological Network Analysis
Littoral
Offshore wind farms
Diversity
Neogene
Tomography
Morocco
Sediment transport
Ecosystem functioning
Changement climatique
Non-native species
Coast
Sediments
Bay of Seine
Mediterranean Sea
Deposition
Watershed
Estuary
Continuous wavelet transform
Géoradar
Geochemistry
Sédiments
Sediment core
Modelling
Tectonics
Alderney Race
English channel
Autocorrelation
Karst
Géochimie
Baie de Seine
Hydrodynamics
Organic matter
Deep learning
Seine estuary
Hydraulic tomography