Stéphane Audry

Stéphane Audry
Université Toulouse III - Paul Sabatier | UPS Toulouse · Laboratoire Géosciences Environnement Toulouse - UM 97 (UMR 5563 / UMRD 234) - GET

PhD

About

119
Publications
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3,615
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Additional affiliations
September 1998 - October 2003
Université Bordeaux-I
Position
  • PhD Student

Publications

Publications (119)
Article
Full-text available
A hydrological and hydrochemical database (produced by the M-TROPICS critical zone observatory) in the upper Nyong Basin from 1998 to 2017 was used to evaluate the river’s response to climatic and anthropogenic forcing and examine chemical weathering processes. SiO2 and HCO3 constitute about 85 % of the Total dissolved solids (TDS) load, equivalent...
Article
Full-text available
Mining areas and in particular those containing massive sulfides have left a heavy environmental legacy with soils and hydrographic networks highly contaminated with metals and metalloids as for example in the Iberian Pyrite Belt (Huelva, Spain). Here, we present new data on copper (Cu) isotopic composition of waters and solids collected along a co...
Article
Full-text available
Due to its insulating and draining role, assessing ground vegetation cover properties is important for high-resolution hydrological modeling of permafrost regions. In this study, morphological and effective hydraulic properties of Western Siberian Lowland ground vegetation samples (lichens, Sphagnum mosses, peat) are numerically studied based on to...
Chapter
Estuaries are the major conduits of material transfer from the continental river basins to the marine environments. In this study, suspended particulate matter (SPM) was collected from the estuarine region of Nethravati River, southwest India, over a one-year period on a seasonal basis to assess the metal fluxes to the eastern Arabian Sea. The focu...
Presentation
Full-text available
Boreal regions dynamics are strongly driven by perennially frozen soil (permafrost) physical properties. Sphagnum moss, lichen, and peat are widely present in these regions, forming a complex biological patchwork covering millions of km². In such regions, energy and mass transfers mainly occur via evapotranspiration, involving both vegetation hydra...
Preprint
Full-text available
The hydraulic properties of ground vegetation cover are important for high resolution hydrological modeling of permafrost regions, due to its insulating and draining role. In this study, the morphological and effective hydraulic properties of Western Siberian Lowland ground vegetation samples (lichens, Sphagnum mosses, peat) are numerically assesse...
Preprint
The hydraulic properties of ground vegetation cover are important for high resolution hydrological modeling of permafrost regions, due to its insulating and draining role. In this study, the morphological and effective hydraulic properties of Western Siberian Lowland ground vegetation samples (lichens, Sphagnum mosses, peat) are numerically assesse...
Preprint
The hydraulic properties of ground vegetation cover are important for high resolution hydrological modeling of permafrost regions, due to its insulating and draining role. In this study, the morphological and effective hydraulic properties of Western Siberian Lowland ground vegetation samples (lichens, Sphagnum mosses, peat) are numerically assesse...
Presentation
Full-text available
Sphagnum moss, lichen and peat are widely present in arctic regions, covering millions of km² in permafrost-dominated regions. This multi-component low vegetation strata plays a key role in surfaces fluxes in these areas, as they are the most widespread interface between the atmosphere and the geosphere. Therefore, characterizing their transfer pro...
Article
Arsenic (As) and antimony (Sb) are potentially hazardous metalloids and their presence in the environment is often related to mineral deposits, mines, and thermal springs. Despite their similar chemical properties, the distribution and behavior of As and Sb in nature has been shown to differ. In order to contribute to a better understanding of As a...
Article
Full-text available
Tropical rivers emit large amounts of carbon dioxide (CO2) to the atmosphere, in particular due to large wetland-to-river carbon (C) inputs. Yet, tropical African rivers remain largely understudied, and little is known about the partitioning of C sources between wetland and well-drained ecosystems to rivers. In a first-order sub-catchment (0.6 km2)...
Presentation
Full-text available
Western Siberia lowlands vegetation cover consists of a complex patchwork of bryophytes (mosses s.l.), lichens (symbiotic association of heterotrophic Fungus and autotrophic Algae) and underlying peat (Volkova et al., 2018). This vegetation cover is the main interface between permafrost driven soil dynamics and the atmosphere. The energetic transfe...
Article
Despite the importance of tropical ecosystems for climate regulation, biodiversity, water and nutrient cycles, only a few Critical Zone Observatories (CZOs) are located in the tropics. Among these, most are in humid climates, while very few data exist for semi‐arid and sub‐humid climates, due to the difficulty of estimating hydro‐geochemical balanc...
Preprint
Full-text available
We characterized the spatio-temporal dynamics of carbon (C) in rivers of the tropical Nyong catchment (South Cameroon). In 2016, we measured fortnightly at 6 locations along an upstream-downstream gradient from groundwater to the main stream of order 6, total alkalinity, dissolved inorganic C (DIC) used together with pH to compute pCO2, dissolved a...
Article
Full-text available
Simultaneously acquiring time series of climate, hydrology and hydrochemical data over decades on river systems is pivotal to understand the complex interactions involving rock, soil water, air and biota in the Critical Zone, to build integrated modeling and to propose predictive scenarios. Among the Critical Zone Observatories (CZOs) implemented i...
Article
Mountain regions of the humid tropics are characterized by steep slopes and heavy rains. These regions are thus prone to both high surface runoff and soil erosion. In Southeast Asia, uplands are also subject to rapid land-use change, predominantly as a result of increased population pressure and market forces. Since 1998, the Houay Pano site, locat...
Article
Mining in the Bolivian Altiplano is important and has historically provided much of the world’s Ag, Sn, and Sb. This study aims to better understand the effects of important recent increases in Bolivian mining on the deposition of metals and metalloids in sediment near Oruro, Bolivia’s fifth largest city, with special attention to natural and anthr...
Presentation
Full-text available
Permafrost is a peculiar soil type of cold areas that is year-round frozen in-depth. Permafrost dynamics (e.g.: seasonal freeze/thaw cycles close to the surface, extension/retreat under climate changes) as strong impacts on both natural processes and engineering activities in cold regions (e.g.: Walvoord and Kurylyk, 2016). The involved physics are...
Presentation
Full-text available
Le permafrost (pergélisol) est un type de sol spécifique des régions froides, qui est gelé toute l'année en profondeur. La dynamique du permafrost (e.g.: cycle saisonniers de gel/dégel près de la surface, extension/retrait latéral sous changement climatique) a des impacts importants aussi bien sur les processus naturels que sur les activités humain...
Conference Paper
Full-text available
(english version below) Эвапотранспирация растений – важнейший параметр, контролирующий динамику гидрологического и теплового режима почв на водосборных бассейнах зоны бореальных лесов. В частности в криолитозоне, эвапотранспирационные потоки оказывают существенное воздействие на мощность сезонно-талого слоя, главным образом из-за их влияния на со...
Presentation
Full-text available
(english version below) Эвапотранспирация растений – важнейший параметр, контролирующий динамику гидрологического и теплового режима почв на водосборных бассейнах зоны бореальных лесов. В частности в криолитозоне, эвапотранспирационные потоки оказывают существенное воздействие на мощность сезонно-талого слоя, главным образом из-за их влияния на с...
Article
Elemental profiles of wines have been used successfully to distinguish their geographical provenience around the world; however, underlying mechanisms are poorly understood. In this study, Ba, Ca, Mg, Mn and Sr contents were determined in 215 wines from several West European wine-growing areas using an easy-to-perform analysis based on ICP-OES. Maj...
Presentation
Full-text available
The biogeochemical transfers in the catchment of the Kulingdakan stream, which is a small tributary of the Kochechum river in the Yenisei basin, have been studied for more than a decade. Measurements of the chemical composition of the waters in the stream and in the other compartments of the watershed, such as mineral soil or litter horizons for in...
Data
This file contains a presentation that gives some information about the validation of the solver permaFoam (Orgogozo et al., 2019)* in the framework of the Interfrost international benchmark (Grenier et al., 2018)**. * L. Orgogozo, A.S. Prokushkin, O.S. Pokrovsky, C. Grenier, M. Quintard, J. Viers, D. Labat, S. Audry, 2019. Water and energy transf...
Data
this file contains the three appendixes listed hereafter: Appendix S1: Full set of governing equations and parameterizations considered for the description of the water and thermal transfer in variably saturated porous media with freeze/thaw of the pore water. Appendix S2: Used data set for the thermo-hydrological properties of the soils. Appendi...
Preprint
Full-text available
This is the preprint of the paper "Water and energy transfer modeling in a permafrost‐ dominated, forested catchment of Central Siberia: The key role of rooting depth" by L. Orgogozo , A.S. Prokushkin, O.S. Pokrovsky, C. Grenier, M. Quintard, J. Viers and S. Audry, published in Permafrost and Periglacial Processes in 2019.
Code
PermaFoam is an OpenFOAM (openfoam.com) solver for cryohydrogeology. It solves coupled water and heat transfers in variably saturated porous media, considering freeze/thaw of the pore water. The main field of application is the modeling of permafrost thermo-hydrological dynamics. A first example of application may be found in the paper "Water and e...
Article
Full-text available
To quantify the impact of evapotranspiration phenomena on active layer dynamics in a permafrost‐dominated forested watershed in Central Siberia, we performed a numerical cryohydrological study of water and energy transfer using a new open source cryohydrogeology simulator, with two innovative features: spatially distributed, mechanistic handling of...
Article
Full-text available
Core Ideas OZCAR is a network of sites studying the critical zone. OZCAR covers various disciplines. OZCAR will help disciplines to work together for a better representation and modeling of the critical zone. The French critical zone initiative, called OZCAR (Observatoires de la Zone Critique–Application et Recherche or Critical Zone Observatories...
Preprint
Full-text available
Evapotranspiration has a major control on continental surfaces dynamics in forested boreal environments. For example, it has strong impacts on active layer thickness, mainly because of its effect on water content within the upper layers of the soil column. These are complex processes, depending not only on climate forcings (atmospheric water demand...
Presentation
Full-text available
Oral presentation given at the 5th EUropean Conference On Permafrost (EUCOP 5) held in Chamonix, France (25th-29th june 2018).
Article
Full-text available
The sources of REY-Th-U and long-term mass balance were assessed in the gneissic tropical forested Critical Zone Observatory of Mule Hole, India. The study relies on the characterization of the solid compartments (bedrock, soils, streambed and suspended sediments), on batch leaching experiments of the parent gneiss and on extractions of cation-exch...
Article
Full-text available
Freshwater reservoirs are a significant source of CO2 to the atmosphere. CO2 is known to be emitted at the reservoir surface by diffusion at the air–water interface and downstream of dams or powerhouses by degassing and along the river course. In this study, we quantified total CO2 emissions from the Nam Theun 2 Reservoir (Lao PDR) in the Mekong Ri...
Article
Assessing the dynamics of the silica cycle in the critical zone remains challenging, particularly within the soil, where multiple processes are involved. To improve our understanding of this cycle in the Tropics, and more specifically the role played by vegetation, we combined elemental Si mass balance with the δ³⁰Si signatures of the compartments...
Article
Full-text available
Background and aims The benefits of Si for crops is well evidenced but the biogeochemical cycle of Si in agriculture remains poorly documented. This study aims at identifying and quantifying the Si sources (primary and secondary soil minerals, amorphous silica, irrigation, Si-fertilizer) to rice plants. Method Field experiments were carried out wi...
Article
Copper (Cu) based pesticides are widely used in viticulture and are permitted in organic viticulture. Due to its extensive long term use, Cu accumulates in vineyard soils and ecotoxicological implications are growing. In this study, the cycling of Cu based pesticides was investigated in vineyard environments using copper mass balance, electron para...
Article
Full-text available
Freshwater reservoirs are a significant source of CO2 to the atmosphere. CO2 is known to be emitted at the reservoir surface by diffusion at the air-water interface and downstream of dams or powerhouses by degassing and along the river course. In this study, we quantified total CO2 emissions from the Nam Theun 2 Reservoir in the Mekong River waters...
Conference Paper
Full-text available
Copper (Cu) isotope analysis has been a powerful tool, discovering redox steps in plant uptake. Nevertheless a disaccord remains in scientific literature regarding Cu isotope fractionation due to transport within the plant. Some studies provide evidence for light isotope accumulation in aerial parts of plants as well as in young with respect to old...
Presentation
Full-text available
This work presents a numerical solver for the multiphysics problem of hydric and thermal transfers in variably water saturated porous media with freeze/thaw of the poral water. The application that we aim to deal with is the study of the dynamics of permafrosts, which are constituted of soils and geological bodies frozen in depth all year round, wi...
Article
Full-text available
Lake Uru Uru (3686 m a.s.l.) located in the Bolivian Altiplano region receives both mining effluents and urban wastewater discharges originating from the surrounding local cities which are under rapid development. We followed the spatiotemporal distribution of different mercury (Hg) compounds and other metal(oid)s (e.g., Fe, Mn, Sb, Ti and W) in bo...
Article
Agriculture has been increasingly relying on groundwater irrigation for the last decades, leading to severe groundwater depletion and/or nitrate contamination. Understanding the links between nitrate concentration and groundwater resource is a prerequisite for assessing the sustainability of irrigated systems. The Berambadi catchment (ORE-BVET/Kabi...
Conference Paper
Full-text available
Copper (Cu) based fungicides have been applied in European vineyards from the appearance of mildew in the late 19th century to the present day, particularly in organic viticulture. Even though its application is foliar, most of the Cu reaches the soil after being washed off or following leaf fall. As Cu accumulates in soils, the use of Cu based fun...
Presentation
Full-text available
This work presents a numerical study of water and energy transfers within a permafrost dominated experimental watershed of Central Siberia, the Kulingdakan catchment (e.g.: Viers et al., 2015). This watershed has been studied for years in order to characterize and quantify the elementary transfers from the slopes to the stream along the seasonal cy...
Conference Paper
Full-text available
PermaFoam est un solveur OpenFOAM® dédié au problème de transferts couplés hydriques et thermiques dans un sol avec gel/dégel de la phase aqueuse. Il a été développé pour l'étude de la dynamique thermo-hydrique des pergélisols dans un contexte de changement climatique, l’objectif étant de contribuer à la quantification des flux élémentaires des sur...
Article
Full-text available
Methylation and demethylation represent major transformation pathways regulating the net production of methylmercury (MMHg). Very few studies have documented Hg reactivity and transformation in extreme high-altitude lake ecosystems. Mercury (Hg) species concentrations (IHg, MMHg, Hg°, and DMHg) and in situ Hg methylation (M) and MMHg demethylation...
Conference Paper
Full-text available
Understanding the influence of soil composition in wine taste is of great economic and environmental interest in France and around the world. Nevertheless the impact of soil composition on wine taste is still controversially discussed. Since inorganic soil components do not have a proper taste and do not enter the plant anyway, their influence need...
Article
River water composition (major ion and 87Sr/86Sr ratio) was monitored on a monthly basis over a period of three years from a mountainous river (Nethravati River) of southwestern India. The total dissolved solid (TDS) concentration is relatively low (46 mg L-1) with silica being the dominant contributor. The basin is characterized by lower dissolved...
Article
Full-text available
Systematic monitoring of subsurface hydrogeochemistry has been carried out for a period of one year in a humid tropical region along the Nethravati–Gurupur River. The major ion and stable isotope (d18O and d2H) compositions are used to understand the hydrogeochemistry of groundwater and its interaction with surface water. In the study, it is observ...
Article
Full-text available
The small experimental watershed of Mule Hole has been monitored for hydrology and chemistry since the last decade at hourly frequency for stream and monthly frequency for groundwater. It is covered by a dry tropical forest which generates intense evapotranspiration, limiting both runoff and groundwater recharge. Stream and groundwater fluxes are t...
Article
The proportion of chemical elements passing through vegetation prior to being exported in a stream was quantified for a forested tropical watershed (Mule Hole, South India) using an extensive hydrological and geochemical monitoring at several scales. First, a solute annual mass balance was established at the scale of the soil-plant profile for asse...
Article
Full-text available
The study presents a 3-year time series data on dissolved trace elements and rare earth elements (REEs) in a monsoon-dominated river basin, the Nethravati River in tropical Southwestern India. The river basin lies on the metamorphic transition boundary which separates the Peninsular Gneiss and Southern Granulitic province belonging to Archean and T...
Article
A combination of mineralogical (SEM–EDS, EMPA) and geochemical (redox dynamics, selective extractions) approaches was applied to mining- and smelting-impacted sediments from Lake Uru Uru and from the Cala Cala Lagoon, a non-impacted reference site, in the Bolivian Altiplano. The purpose was to assess the factors controlling the post-depositional re...
Conference Paper
There is a rising concern over the contribution of hydroelectric reservoirs to global anthropogenic greenhouse gases (GHGs) emissions. We present here the first comprehensive assessment of GHGs footprint associated with the creation of the Nam Theun 2 (NT2) hydroelectric reservoir in subtropical region of the Lao People's Democratic Republic. This...
Article
Full-text available
The comparison between contemporary and long-term weathering has been carried out in the Small Experimental Watershed (SEW) of Nsimi, South Cameroon in order to quantify the export fluxes of major and trace elements and the residence time of the lateritic weathering cover. We focus on the hillside system composed of a thick lateritic weathering cov...
Article
Warming of the permafrost accompanied by the release of ancient soil organic carbon is one of the most significant environmental threats within the global climate change scenario. While the main sites of permafrost carbon processing and its release to the atmosphere are thermokarst (thaw) lakes and ponds, the main carriers of carbon and related maj...
Article
Full-text available
Active processes of permafrost thaw in Western Siberia increase the number of soil subsidencies, thermokarst lakes and thaw ponds. In continuous permafrost zones, this process promotes soil carbon mobilisation to water reservoirs, as well as organic matter (OM) biodegradation, which produces a permanent flux of carbon dioxide (CO2) to the atmospher...