Search results for "Universe"
showing 10 items of 2171 documents
Erosion des sols du Cap Vert : processus et quantification à l'échelle de trois Bassins Versants de l'île de Santiago
2010
The archipelago of Cape Verde comprises 10 volcanic islands and belongs to the Sahelian zone stretching from the Atlantic to the Red Sea. Since several decades, Cape Verde is affected by desertification caused largely by climatic recession and soil erosion. These factors, coupled with high population pressure on resources, rugged topography and torrential tropical rains, cause serious losses of lands. However, since its independence in 1975, the Government conducted an extensive program of afforestation, soil and water conservation. Nevertheless very little research has been conducted to evaluate the actions of protection and conservation of soil and water. Therefore, there is no data on th…
Lien entre la diversité microbienne, la stabilité des communautés microbiennes et le turnover des matières organiques du sol
2014
Soil microbial communities act as important agents of the biological soil functioning, particularly through their involvements in the transformations of biogeochemical cycles (C, N, P…). In agro-ecosystems, the diversity of these communities is affected by perturbations associated to agricultural practices, and the significance of these modifications in terms of preservation of biological functioning and sustainability of agricultural systems has emerged as a central issue in the environmental sciences. Whereas the role of biodiversity has been well studied for macroorganisms, in particular for plants; the biodiversity/activity relationship is still largely unknown for soil microorganisms. …
Widespread diminishing anthropogenic effects on calcium in freshwaters
2019
Calcium (Ca) is an essential element for almost all living organisms. Here, we examined global variation and controls of freshwater Ca concentrations, using 440 599 water samples from 43 184 inland water sites in 57 countries. We found that the global median Ca concentration was 4.0 mg L−1 with 20.7% of the water samples showing Ca concentrations ≤ 1.5 mg L−1 , a threshold considered critical for the survival of many Ca-demanding organisms. Spatially, freshwater Ca concentrations were strongly and proportionally linked to carbonate alkalinity, with the highest Ca and carbonate alkalinity in waters with a pH around 8.0 and decreasing in concentrations towards lower pH. However, on a temporal…
Zinc isotopes in Late Pleistocene fossil teeth from a Southeast Asian cave setting preserve paleodietary information
2020
Significance Dietary habits, especially meat consumption, represent a key aspect in the behavior and evolution of fossil hominin species. Here, we explore zinc (Zn) isotope ratios in tooth enamel of fossil mammals. We show discrimination between different trophic levels and demonstrate that Zn isotopes could prove useful in paleodietary studies of fossil hominin, or other mammalian species, to assess their consumption of animal versus plant resources. We also demonstrate the high preservation potential of pristine diet-related Zn isotope ratios, even under tropical conditions with poor collagen preservation, such as the studied depositional context in Southeast Asia. However, assessing the …
Biodiversité des sols viticoles: un héritage des modes d'occupation et des pratiques culturales anciennes?
2018
3 pages; National audience
Une tombe creusée dans un ancien chenal de rivière
2022
Des pierres pour une tombe princière
2022
la préservation et la pérennisation des sols viticoles en Bourgogne du Moyen Âge à nos jours
2018
Rencontres du Clos Vougeot 2017; International audience; tout discours actuel sur les terroirs et la qualité des vins en Bourgogne passe par une certaine tradition ancrée dans le sol. C'est là même que l'on fonde l'essence du terroir d'où les sensations gustatives sont directement tirées 1 ; un discours qui naît au XVIII e s. seulement, devenu caractéristique de la Bourgogne viticole et qui rencontre la tradition reconstruite au point de créer des mythes nouveaux comme celui des moines cisterciens qui auraient « goûté la terre » pour délimiter leurs clos au Moyen Âge. C'est une vieille idée analogiste déjà présente chez les auteurs antiques et retrouvée chez ceux du XVI e s. comme Jean Lieb…