Steeve Bonneville
Université libre de Bruxelles, Faculté des Sciences, Faculty Member
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Research Interests:
Research Interests:
Research Interests:
Trees and their associated rhizosphere organisms play a major role in mineral weathering driving calcium fluxes from the continents to the oceans that ultimately control long-term atmospheric CO 2 and climate through the geochemical... more
Trees and their associated rhizosphere organisms play a major role in mineral weathering driving calcium fluxes from the continents to the oceans that ultimately control long-term atmospheric CO 2 and climate through the geochemical carbon cycle. Photosynthate allocation to tree roots and their mycorrhizal fungi is hypothesized to fuel the active secretion of protons and organic chelators that enhance calcium dissolution at fungal-mineral interfaces. This was tested using 14 CO 2 supplied to shoots of Pinus sylvestris ectomycorrhizal with the widespread fungus Paxillus involutus in monoxenic microcosms, revealing preferential allocation by the fungus of plant photoassimilate to weather grains of limestone and silicates each with a combined calcium and magnesium content of over 10 wt.%. Hyphae had acidic surfaces and linear accumulation of weathered calcium with secreted oxalate, increasing significantly in sequence: quartz, granite < basalt, olivine, limestone < gabbro. These ...
We present an overview of the application of analytical electron microscopy to the study of the interfacial interaction between organic materials and inorganic mineral phases. Two overall themes are considered: biomineralisation and... more
We present an overview of the application of analytical electron microscopy to the study of the interfacial interaction between organic materials and inorganic mineral phases. Two overall themes are considered: biomineralisation and biomediated demineralisation involving studies of the structure of the iron storage protein ferritin [1] and an investigation of biotite mineral weathering by mycorrhizal fungi [2]. The current generation of (scanning) transmission electron microscopes (S/TEMs) can readily provide atomic scale resolution ...
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The Weathering Science Consortium is a multi-disciplinary project that aims to create a step change in understanding how biota control mineral weathering and soil formation (http://www.wun.ac.uk/wsc). Our hypothesis is that rates of... more
The Weathering Science Consortium is a multi-disciplinary project that aims to create a step change in understanding how biota control mineral weathering and soil formation (http://www.wun.ac.uk/wsc). Our hypothesis is that rates of biotic weathering are driven by the energy supply from plants to the organisms, controlling their biomass, surface area of contact with minerals and their capacity to interact chemically
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Research Interests:
Research Interests:
Iron (Fe) is a key micronutrient regulating primary productivity in many parts of the global ocean. Dust deposition is an important source of Fe to the surface ocean, but most of this Fe is biologically unavailable. Atmospheric processing... more
Iron (Fe) is a key micronutrient regulating primary productivity in many parts of the global ocean. Dust deposition is an important source of Fe to the surface ocean, but most of this Fe is biologically unavailable. Atmospheric processing and reworking of Fe in dust aerosol can increase the bioavailable Fe inputs to the ocean, yet the processes are not well understood. Here, we experimentally simulate and model the cycling of Fe-bearing dust between wet aerosol and cloud droplets. Our results show that insoluble Fe in dust particles readily dissolves under acidic conditions relevant to wet aerosols. By contrast, under the higher pH conditions generally relevant to clouds, Fe dissolution tends to stop, and dissolved Fe precipitates as poorly crystalline nanoparticles. If the dust-bearing cloud droplets evaporated again (returning to the wet aerosol stage with low pH), those neo-formed Fe nanoparticles quickly redissolve, while the refractory Fe-bearing phases continue to dissolve gra...
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Research Interests: Geology, Multidisciplinary, High Resolution Transmission Electron Microscopy, Applied, Applied Environmental Microbiology, and 9 moreMagnetotactic Bacteria, Iron Oxide, Magnetic Domains, Energy Dispersive X-Ray Analysis, Environmental Conditions, Particle Size, Hydrogen Sulfide, Chemical Composition, and Crystal Size Distribution
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Research Interests:
Research Interests:
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Research Interests: Geology, Geochemistry, Kinetics, Scanning Transmission Electron Microscopy, Focused Ion Beam, and 10 moreMineral weathering, Energy Dispersive X-Ray Analysis, Mycorrrizae Weathering Rate, Nanoscale Processes, Elemental Fluxes During Weeathering, Burns, Pinus sylvestris, Scots Pine, Root System, and Organic Matter
Research Interests: Geology, Geochemistry, Transmission Electron Microscopy, Carbon Cycle, Differential scanning calorimetry, and 10 moreHawaiian Islands, Mineral Composition, Phase Transformation, Surface Area, Time Dependent, Early Terrestrial Ecosystems, Chemical Composition, X Ray Photoelectron Spectroscopy, Organic Matter, and Physico chemical Properties
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Research Interests: Dust (Physics), Atmospheric Aerosols, Scanning Electron Microscopy, Dust (Astronomy & Astrophysics), Nanoparticles, and 11 moreMultidisciplinary, Environmental science and technology, Aerosols, Atmosphere, Iron Nanoparticles, Iron, Theoretical Models, Surface Properties, Dust, Environmental, and Ferric Compounds
Research Interests:
Research Interests:
Research Interests: Geology and Geochemistry
Research Interests:
Iron is a critical nutrient for the control of primary productivity in the global ocean. One of the most important sources of iron to offshore surface waters is from aerosol input, particularly dust input. One of the critical... more
Iron is a critical nutrient for the control of primary productivity in the global ocean. One of the most important sources of iron to offshore surface waters is from aerosol input, particularly dust input. One of the critical uncertainties in modelling the global impact of aerosol iron input to the ocean is the aerosol solubility and bioavailability (Jickells et al., 2005). Many studies have indicated that the atmospheric processing could increase the solubility of iron in mineral dust (Spokes and Jickells, 1994; Baker and Jickells, 2006; Meskhidze et al., ...
Classical studies of biotic weathering have mainly focussed on solution phase interactions with minerals and on the ability of plants and microorganisms to influence soil solution composition. Only recently, has the relevance of direct... more
Classical studies of biotic weathering have mainly focussed on solution phase interactions with minerals and on the ability of plants and microorganisms to influence soil solution composition. Only recently, has the relevance of direct (contact) interactions between fungi and minerals been recognized as an important driver in weathering environments. This can be examplified by the fungal components of lichen symbioses or the ectomycorrhizal association between plants and fungi.
We present an overview of the application of analytical electron microscopy to the study of the interfacial interaction between organic materials and inorganic mineral phases. Two overall themes are considered: biomineralisation and... more
We present an overview of the application of analytical electron microscopy to the study of the interfacial interaction between organic materials and inorganic mineral phases. Two overall themes are considered: biomineralisation and biomediated demineralisation involving studies of the structure of the iron storage protein ferritin [1] and an investigation of biotite mineral weathering by mycorrhizal fungi [2]. The current generation of (scanning) transmission electron microscopes (S/TEMs) can readily provide atomic scale resolution ...
Research Interests:
In late 1980s, at an informal lecture at the Woods Hole Oceanographic Institution, oceanographer John Martin said,''Give me a half tanker of Fe, and I will give you an ice age.''These provocative words were related to... more
In late 1980s, at an informal lecture at the Woods Hole Oceanographic Institution, oceanographer John Martin said,''Give me a half tanker of Fe, and I will give you an ice age.''These provocative words were related to a theory subsequently known as the ''Fe hypothesis'', which was proposed by Martin and Fitzwater (1988) and Martin (1990), based on the inverse relationship of particulate Fe supply and measured CO2 concentration in the Vostok ice core (Martin, 1990). The first meso-scale Fe fertilization experiment in 1993 ...
The large variations in pH of natural cloud water may lead to changes in phases of the iron (Fe) minerals in the dust. The speciation and reactivity of the Fe phases in dusts incorporate into clouds are however, not known. In this study,... more
The large variations in pH of natural cloud water may lead to changes in phases of the iron (Fe) minerals in the dust. The speciation and reactivity of the Fe phases in dusts incorporate into clouds are however, not known. In this study, we investigated the changes in Fe speciation during simulated cloud processing of two Saharan soil samples using traditional Fe sequential extraction techniques and modern ultrahigh resolution microscopic and diffraction techniques. The variations in pH within natural clouds were simulated ...