Relative weathering intensity of calcite versus dolomite in carbonate‐bearing temperate zone watersheds: Carbonate geochemistry and fluxes from catchments within the St. Lawrence and Danube river basins

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94958/1/ggge940.pd

High potential for weathering and climate effects of non-vascular vegetation in the Late Ordovician

It has been hypothesized that predecessors of today’s bryophytes significantly increased global chemical weathering in the Late Ordovician, thus reducing atmospheric CO2 concentration and contributing to climate cooling and an interval of glaciations. Studies that try to quantify the enhancement of weathering by non-vascular vegetation, however, are usually limited to small areas and low numbers of species, which hampers extrapolating to the global scale and to past climatic conditions. Here we present a spatially explicit modelling approach to simulate global weathering by non-vascular vegetation in the Late Ordovician. We estimate a potential global weathering flux of 2.8 (km3 rock) yr−1, defined here as volume of primary minerals affected by chemical transformation. This is around three times larger than today’s global chemical weathering flux. Moreover, we find that simulated weathering is highly sensitive to atmospheric CO2 concentration. This implies a strong negative feedback between weathering by non-vascular vegetation and Ordovician climate

Effects of CO 2 and nutrient availability on mineral weathering in controlled tree growth experiments

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94968/1/gbc911.pd

Report on research context and practice in the Université d Franche-Comté (France), catalogues of experiences, deliverable 34 of caENTI, project funded under FP6 research program of the European Union.

deliverable 34 of caENT

Work Package 5: Proposal of an European Letter of Quality on Action-Research Favoring Territorial Governance of Sustainable Development.

International audienc

Influence of acid rain on CO2 consumption by rock weathering : local and global scales

Sulphuric and nitric acids, which are supplied by acid precipitation, take over from carbonic acid in weathering reactions, which induced a decrease of the atmospheric/soil CO2 consumption by weathering (WCO2). In order to quantity this disturbance, one has compared the bicarbonate fluxes determined at the outlet of 2 small catchments (one is substantially disturbed and the other is is weakly disturbed by acid precipitation). Out study shows that, under the influence of acid precipitation, bicarbonate fluxes (i.e. WCO2) are decreased by about 73%. It has also been attempted to simulate at the continental scale, the influence of acid precipitation on WCO2, using a Global Erosion Model (GEM-CO2) recently developed. Several simulations have been performed corresponding to different realistic scenarios of global acid precipitation. In the most pessimistic of these scenarios, the GEM-CO2 simulation shows that the global WCO2 would be decreased by no more than 10%

Enquêtes collectives

Au coeur de notre collectif de recherche, une question : comment la mobilité humaine façonne-t-elle les sociétés qu'elle traverse et qu'elle lie ? L'envie de comprendre les implications des transferts économiques et sociaux des migrants a donné naissance à un dispositif empirique transnational original. Cette enquête collective a conduit des économistes et des sociologues à collaborer, de part et d'autre du Sahara, pour collecter ensemble des données entre Paris, Dakar, Thiès et quatre localités du Sénégal rural. Cet article présente la manière dont l'objet d'étude a été conçu puis réapproprié par les participants à l'enquête. Le regard rétrospectif posé ici sur cette aventure scientifique et humaine souligne la nécessité de penser la matérialité des dynamiques intellectuelles pour permettre la coopération entre chercheurs de statuts et d'horizons disciplinaires différents, évoluant dans des contextes (notamment institutionnels) asymétriques