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Publications (163)
On a global scale, wetlands are suffering from a steady decline in surface area and environmental quality. Protecting them is essential and requires a careful spatialisation of their natural habitats. Traditionally, in our study area, species discrimination for floristic mapping has been achieved through on-site field inventories, but this approach...
Pseudomonas fluorescens is a siderophore producing bacteria that is expected to alter the mobility and bioavailability of Cu in vineyard soils due to its ability to produce pyoverdine under iron deficiency. In this study, we monitored the effect of this bacterial species, particularly the production of siderophore, on the mobility and bioavailabili...
Hyper-DRELIO (Hyperspectral DRone for Environmental and LIttoral Observations) is a custom, mini-UAV (unmanned aerial vehicle) platform (<20 kg), equipped with a light push broom hyperspectral sensor combined with a navigation module measuring position and orientation. Because of the particularities of UAV surveys (low flight altitude, small spatia...
Merci de ne rien inscrire dans cette zone et ne pas modifier les marges des pieds de page et entêtes. Ne rien inscrire dans cette zone et ne pas modifier les marges des pieds de page et entêtes sans quoi votre résumé sera systématiquement refusé Merci de ne rien inscrire dans cette zone et ne pas modifier les marges des pieds de page et entêtes. Ti...
Habitat mapping is an essential tool to implement the European Habitats Directive 92/43/EEC and to manage the Natura 2000 protected areas network. However, their elaboration is most often based on field surveys, which are time-consuming and expensive when dealing with large areas. In this study, we aimed to evaluate the contribution of Sentinel-2 s...
Oxygen and nitrate availabilities impact the marine nitrogen cycle at a range of spatial and temporal scales. Here, we demonstrate the impact of denitrifying foraminifera on the nitrogen cycle at two oxygen and nitrate contrasting stations in a fjord environment (Gullmar Fjord, Sweden). Denitrification by benthic foraminifera was determined through...
Due to the coastal morphodynamic being impacted by climate change there is a need for systematic and large-scale monitoring. The monitoring of sandy dunes in Pays-de-la-Loire (France) requires a simultaneous mapping of (i) its morphology, allowing to assess the sedimentary stocks and (ii) its low vegetation cover, which constitutes a significant pr...
Oxygen availability impacts the marine nitrogen cycle at a range of spatial and temporal scales. Invasive organisms have shown to sustainably affect sediment geochemistry and benthic ecology. Nonionella sp. T1 was recently described as an invasive benthic foraminifer in the North Sea region. Here, we demonstrate the impact of this denitrifying spec...
Mapping coastal dune vegetation is critical to understand dune mobility and resilience in the context of climate change, sea level rise, and increased anthropogenic pressure. However, the identification of plant species from remotely sensed data is tedious and limited to broad vegetation communities, while such environments are dominated by fragmen...
We have studied by high-resolution X-ray Computed Tomography the effect of crystal clustering on the Shape-Preferred Orientation (SPO) development in synthetic magmas experimentally deformed at 300 MPa and 475–550°C. A fully connected solid network that could potentially induce the onset of yield strength is not achieved in these suspensions contai...
Hi everybody !
I am glad to share with you what I have presented for the Following worshops:
- WHISPERS (Workshop on Hyperspectral Images and Signal Processing: Evolution in Remote Sensing) and
- SFPT-GH (Société Française de Photogrammétrie et Télédétection - Groupe Hyperspectral)
This presentation summaries the main principles of our methodo...
Benthic manganese cycle studied with 2D high spatial resolution methods at contrasted oxygen conditions in Gullmar Fjord (Sweden)
The OR2C (Observatoire Régional des Risques Côtiers) is a new observatory of coastal hazards located in the Pays de la Loire region on the Atlantic coast of France. It was created, in 2016, in a context of high regional vulnerability to coastal erosion and storm surges. The OR2C is in charge of monitoring nearly 400 km of coastline. Its major missi...
To be efficient, fisheries need to be built in the intertidal range. Thus, the evolution of their geographical position in time highlights modifications of the coastlines, generally closely related to environmental changes. Along the island of Yeu (Mid-French Atlantic coast), dozens of fisheries were identified. Currently totally submerged, most of...
In shoreline monitoring, only topo-bathymetric light detection and ranging (LiDAR) can map large corridors from aerial dunes to sandbanks in shallow water. Increasing turbidity masking the formation of 532 nm laser beam echoes on the sea bed makes this challenging. Full-waveform recording all the laser beam damping functions, a turbid water column...
Siderophores are natural metal chelating agents that strongly control the biogeochemical metal cycles such as Fe in the environment. This article describes a new methodology to detect and quantify at the micromolar concentration the spatial distribution at millimetre scale of siderophores within the root’s system. The “universal” CAS assay original...
This work is an extension of the MicroPhytoBenthos Optical Model (MPBOM) workflow. The model was based on the observation that the biofilm itself has a negligible inherent reflectance and can be described solely by the ratio between its apparent reflectance (R A) and background reflectance (R B), allowing a straightforward calculation of the absorp...
The monitoring of coastal sand dunes requires regular high-resolution aerial photography along hundreds of kilometers of coastal strips. Light detection and ranging (LiDAR) is now the most widely used method for detailed topographic and vegetation studies. The aim of this work is to show how the full-waveform shapes returned from single or multiple...
Three beach and dune systems located in the northeastern part of the Bay of Biscay in France were monitored over 5 years with a time series of three airborne LiDAR datasets. The three study sites illustrate a variety of morphological beach types found in this region. Reproducible monitoring solutions adapted to basic and complex beach and dune morp...
The implementation of accurate atmospheric correction is a prerequisite for satellite observation and water quality monitoring in coastal areas. The potential of the fast-line-of-sight atmospheric analysis of spectral hypercubes (FLAASH) was investigated here for the medium resolution imaging spectrometer (MERIS). As the comparison between discrete...
The Pacific oyster, Crassostrea gigas (Thunberg), is the main bivalve species cultivated in the world. With global warming enabling its reproduction and larval survival at higher latitudes, this species is now recognized as invasive and creates wild oyster reefs globally. In this study, the spatial distribution of photosynthetic assemblages coloniz...
Relationship between fucoxanthin concentration (expressed in mass of pigment per oyster shell surface) and second derivative peak at 462 nm.
Second derivate values are multiplied by 104.
(PDF)
Detailed list of all diatom taxa found in vertical and horizontal oysters, including details of their relative abundance (%), and their life-forms.
(PDF)
We present the first study identifying and quantifying the production of microbial siderophores in natural environments in 2 dimensions. The method used a slightly modified protocol (Andrews et al., 2016) of the universal CAS assay for siderophore detection (Schynn and Neilands 1986) combined with diffusive equilibrium in thin film (DET). The orang...
The present study describes new procedures to obtain at millimeter resolution the spatial distribution of nitrite and nitrate in porewaters, combining diffusive equilibrium in thin films (DET), colorimetry and hyperspectral imagery. Nitrite distribution can be easily achieved by adapting the well-known colorimetric method from Griess (1879) and usi...
The invasion of the wild oyster Crassostrea gigas along the western European Atlantic coast hasgenerated changes in the structure and functioning of intertidal ecosystems. Considered as an invasivespecies and a trophic competitor of the cultivated conspecific oyster, it is now seen as a resource byoyster farmers following recurrent mass summer mort...
We present a new rapid and accurate
protocol to simultaneously sample benthic living foraminifera in two
dimensions in a centimetre-scale vertical grid and dissolved iron and
phosphorus in two dimensions at high resolution (200 μm). Such an
approach appears crucial for the study of foraminiferal ecology in highly
dynamic and heterogeneous sedimenta...
We present a new rapid and accurate protocol to simultaneously sample benthic living foraminifera in two dimensions in a centimeter scale vertical grid and dissolved iron in high resolution (200 μm). Such an approach appears crucial to study foraminiferal ecology in heterogeneous environments. The foraminiferal faunas of the main intertidal mudflat...
This paper reports the sintering behavior of synthetic inorganic carbonates chemically identical to barytocalcite (BaCa(CO3)2, 8.1 wt.% C), kutnahorite (CaMn(CO3)2, 11.1 mass% C) and rhodochrosite (MnCO3, 10.5 wt.% C) for 14C immobilization. As carbonates are time–temperature dependently subjected to decarbonation due to the loss of carbon dioxide,...
S U M M A R Y The intrusion mechanism and internal structure of sills are still under debate. We present a detailed magnetic study, including anisotropy of magnetic susceptibility and rock magnetic analyses of a Cretaceous (94 Ma), 7-m-thick sill from the Lusitanian Basin in Portugal, the Foz da Fonte sill. The results, from both the top surface an...
This study presents a new approach combining Diffusive Equilibrium in Thin-film (DET) and spectrophotometric methods to determine the spatial variability of dissolved iron and dissolved reactive phosphorous (DRP) with a single gel probe. Its originality is (1) to postpone up to three months the colorimetric reaction of DET by freezing and (2) to me...
Microphytobenthic (MPB) biofilms are taxonomically mixed microbial assemblages (e.g. cyanobacteria, chlorophyta and diatoms) responsible for important estuarine ecosystem functions (e.g. nutrient fluxes, sediment cohesion, and primary productivity). MPB biofilms exhibit high spatial–temporal variation leading to high variability in collected data a...
a b s t r a c t Nowadays the development of sensors for acquiring hyperspectral images has contributed greatly to the identification of different constituents of the earth's surface and therefore to the improvement of carto-graphic products. Carbonate rocks are often altered by physical and chemical processes. The natural tendency in most carbonate...
La té lé dé tection hyperspectrale constitue aujourd'hui, à travers la spectromé trie du terrain, un outil puissant pour la discrimination et l'identification pré cise et rapide des surfaces miné rales. L'objectif de ce travail est l'identification spectrale des faciè s carbonaté s dans le Haut Atlas atlantique marocain, afin de mettre en place une...
La té lé dé tection hyperspectrale constitue aujourd'hui, à travers la spectromé trie du terrain, un outil puissant pour la discrimination et l'identification pré cise et rapide des surfaces miné rales. L'objectif de ce travail est l'identification spectrale des faciè s carbonaté s dans le Haut Atlas atlantique marocain, afin de mettre en place une...
a b s t r a c t Nowadays the development of sensors for acquiring hyperspectral images has contributed greatly to the identification of different constituents of the earth's surface and therefore to the improvement of carto-graphic products. Carbonate rocks are often altered by physical and chemical processes. The natural tendency in most carbonate...
a b s t r a c t Nowadays the development of sensors for acquiring hyperspectral images has contributed greatly to the identification of different constituents of the earth's surface and therefore to the improvement of carto-graphic products. Carbonate rocks are often altered by physical and chemical processes. The natural tendency in most carbonate...
La té lé dé tection hyperspectrale constitue aujourd'hui, à travers la spectromé trie du terrain, un outil puissant pour la discrimination et l'identification pré cise et rapide des surfaces miné rales. L'objectif de ce travail est l'identification spectrale des faciè s carbonaté s dans le Haut Atlas atlantique marocain, afin de mettre en place une...
La té lé dé tection hyperspectrale constitue aujourd'hui, à travers la spectromé trie du terrain, un outil puissant pour la discrimination et l'identification pré cise et rapide des surfaces miné rales. L'objectif de ce travail est l'identification spectrale des faciè s carbonaté s dans le Haut Atlas atlantique marocain, afin de mettre en place une...
a b s t r a c t Nowadays the development of sensors for acquiring hyperspectral images has contributed greatly to the identification of different constituents of the earth's surface and therefore to the improvement of carto-graphic products. Carbonate rocks are often altered by physical and chemical processes. The natural tendency in most carbonate...
a b s t r a c t Nowadays the development of sensors for acquiring hyperspectral images has contributed greatly to the identification of different constituents of the earth's surface and therefore to the improvement of carto-graphic products. Carbonate rocks are often altered by physical and chemical processes. The natural tendency in most carbonate...
Microphytobenthic (MPB) biofilms are taxonomically mixed microbial assemblages (e.g. cyanobacteria, chloro-phyta and diatoms) responsible for important estuarine ecosystem functions (e.g. nutrient fluxes, sediment co-hesion, and primary productivity). MPB biofilms exhibit high spatial–temporal variation leading to high variability in collected data...
Coastal areas are by nature very dynamic environments. Sediments from such aquatic environments constitute very heterogeneous zones especially because of bioturbation (fauna, flora or microbial activity). To understand these environments, major techniques of two-dimensional (2D) distributions of pore-waters of marine sediments were developped by me...
We present a new interpretation of anisotropy of magnetic susceptibility (AMS) fabrics in basaltic lava flows based on the detailed study of magnetic mineralogy and silicate crystallographic fabric of a Quaternary lava flow from the French Massif Central (La Palisse). We consider the model of AMS fabric imbrication between magnetic foliation and fl...
Volcanological processes, such as melt segregation, ascent, and
eruption, are directly dependent on the rheological behavior of magmatic
suspensions. An increase of the crystal fraction of the suspension leads
to the formation of a solid-particle network, which abruptly increases
magma viscosity. The crystal fraction at which this rheological
trans...
The magnetite fabrics measured by anisotropy of magnetic susceptibility (AMS) and by shape preferred orientation (SPO) optical methods are classically used as flow kinematics indicators in lava flows. The development of magnetite fabrics during simple shear strains γ ≤ 20 was performed using a suspension of 1% volume fraction of multidomain magneti...
A new fast mapping approach based on an optical model was developed and applied to hyperspectral airborne HySpex images of Bourgneuf Bay (French Atlantic coast). The aims were (1) to discriminate diatom biofilms (from the Bacillariophyceae class) constituting microphytobenthos on any mudflat and (2) to estimate their biomass expressed in mg Chl a·m...
Benthic microalgae can make a substantial contribution to the food web in coastal
ecosystems, in particular diatoms, which dominate photo‐autotrophic assemblages in
intertidal mudflats. They form dense biofilms in the most superficial sediment layers and
contribute to their stabilization. Many studies investigated the spatio‐temporal dynamics of
th...
Abundance of carbonate and circulation of waters and geochemical
reactions (serpentinization, carbonation) within ultramafic rocks are
examined with hyperspectral airborne data coupled with laboratory
infrared spectroscopy, XRD, and petrologic data .
Quantitative textural analysis including grain shape fabric and clusters formation is a fundamental tool to quantify the deformation during the early magmatic emplacement state of igneous rocks. We analysed the shape preferred orientation (SPO) of both isolated and clustered grain populations in experimentally deformed synthetic magmas by high reso...
Estuarine intertidal sediments are colonized by assemblages of photosynthetic microorganisms grouped under the generic term of microphytobenthos. They form transient biofilms at the sediment surface at low tide and play two major roles: they can represent up to 50% of the total primary production of estuarine water, and contribute to the stabilizat...
In order to support interpretation of the first observations of Vesta by
Dawn, we have measured reflectance spectral images of Vestan meteorites
(howardite, eucrite, diogenite) with an imaging spectrometer at the LPG
in Nantes. We report on the first results of this analysis.
We present the result of the first deformation experiments at high-temperatures and high-pressures on synthetic magmatic suspensions of strongly anisometric particles. The results highlight the interplay between the rheological response and the development of microstructures and they demonstrate the critical importance of the shape of crystals on t...
The Miocene ignimbrites of Mounts Bambouto and Bamenda located in the central part of Cameroon Volcanic Line are generally made of welded and non-welded massive lapilli tuff and lithic breccias. These discontinuous deposits cover a total area of 180km2 with thickness ranging from 25 to 200m. The different facies contain several lithic fragments of...
Micro-algae are one of the most reactive group of photosynthetic organisms regarding pigment composition. Indeed, cells adjust their pigment pool as a physiological response to the extremely variable light environment they inhabit. Thus, because of pigment dynamics and functions, the estimation of absorption properties of these organisms is primord...
