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International audience; Plant products arouse great interest in many fields (construction, automotive, textiles, etc …).However, some of their characteristics as their flammability represent major disadvantagesfor some applications. Research is now being conducted in academia and industry to developeffective methods of functionalizing or modifying the surface of these fibers to improve theirperformance. In this respect, radiation-grafting, based on the use of ionizing radiation(gamma or e-beam), represents an interesting method compared to chemical or enzymaticmethods. This technique makes it possible to generate radicals on the fibers allowing thegrafting of molecules of interest, thus offering a large spectrum of possibilities for themodification of the fibers [1][2]. Two ways for grafting under ionizing conditions can beused (Figure 1), pre irradiation and mutual irradiation. In any case, many factors conditionthe success of grafting reactions. In particular, the structure and the composition of thesubstrate influence the nature of the active species formed, and therefore, the feasibility ofthe grafting reaction. Some techniques, such as Electronic Paramagnetic Resonance (EPR),helps us to better understand these parameters, which will be the subject of this presentation.

In the version of this Article originally published, the affiliation for M. I. Arce was incorrect; it should have been: Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany. This has now been corrected in the online versions of the Article.

National audience; Ce chapitre d'ouvrage est une synthèse des résultats du projet SECALP à destination des gestionnaires et décideurs publics. L’objectif du projet SECALP était d’analyser les mécanismes d’adaptation des territoires semi-naturels de montagne face aux changements climatiques, particulièrement la récurrence des sécheresses. Les objectifs spécifiques étaient : 1) d’améliorer la compréhension des mécanismes de résilience et de transformation des écosystèmes, et des processus d’adaptation des acteurs agricoles et forestiers. 2) de proposer des orientations pour accompagner ces acteurs au travers des politiques publiques agri-environnementales et de développement territorial, et 3) de proposer des stratégies d’observation à long terme pouvant favoriser l’adaptation des acteurs.

1. Nitrogen (N) cycling is a key process determining ecosystem functioning in subalpine grasslands where traditional mowing and manuring are being abandoned. However, the roles of the plant and microbial communities in mediating changes in N availability are still poorly understood. 2. We inoculated 15 subalpine grassland fields with dual-labelled ammonium nitrate (15NH4+, 15NO3 -) during July 2005 and used pool dilutions over 1 month to calculate inorganic N fluxes into the microbial pool and uptake in plant communities by grasses, forbs and legumes. The effects of current land abandonment were assessed by comparing manured and mown terraces (ancient croplands) with other terraces where these practices have ceased, and mown versus unmown unterraced meadows. 3. Rapid cycling of inorganic N and high soil N availability in forb-dominated manured and mown terraces resulted from fast plant N uptake and low microbial CN ratio. In grass-dominated unmown terraces, N cycling was slower and N retention was greater; microbial N uptake remained similar to that in the other terraces, although a higher CN ratio suggested a shift towards fungal dominance. 4. In unterraced meadows, pH was low due to reduced mixing of soil with the underlying calcareous rock. Soil [NH4+] was high and [NO3-] low, but current management had no effect on N pool size, although plant N uptake was greater in the mown than unmown fields. This may be partially explained by high N retention by dominant Festuca paniculata tussocks. The microbial N pool and N uptake were both low and the microbial CN ratio was high, suggesting that fungi slowed N cycling and reduced the influence of mowing on N turnover. 5. Synthesis. In these marginal long-term grasslands, with low productivity and high biodiversity value, changes in ecosystem function associated with reduced management intensity were mediated through slower N cycling. This response was expressed as more gradual nutrient uptake but greater retention by unmown plant communities, slower microbial uptake and smaller soil N pools. In contrast to more productive ecosystems, such as north-western European grasslands, reduced management is detrimental to both biodiversity and the maintenance of soil-related ecosystem services. These costs will need to be balanced against potential benefits, such as carbon storage. © 2009 British Ecological Society.

In order to evaluate the best technical solution to extend the sewage treatment plant of Northern part of NANTES, an assessment of discharge impact upon water quality of Loire estuary, has been realized according to several treatment hypothesis. This analysis allowed us to point out the following facts : -whatever the treatment method, the discharge impact is of no great significance for the following parameters : COD, BOD, TSS, TKN, owing to the importance of upstream contribution ; -however, impact is more significant for fecal bacteria, taking in consideration fixation and concentration processes appearing in the "muddy cork" and for phosphorus (increasing the estuary eutrophication and hence, water desoxygénation). A comprehensive depollution program would emphasize the need to monitor these two last parameters, La mise en place d'une tranche biologique en complément de l'actuelle tranche primaire a été envisagée pour NANTES-Nord. Dans le but de vérifier l'amélioration de la qualité des eaux de l'estuaire susceptible d'être obtenue suite à cet investissement, une étude a comparé l'impact sur la Loire résultant du rejet d'eau usée de NANTES-Nord après différentes hypothèses de traitement. Cette analyse a permis de dégager les faits suivants : -quelque soit le mode de traitement retenu, l'impact des rejets de NANTES-Nord sera négligeable pour les paramètres suivants : DCO, DBO5, MES, NTK, en raison de l'importance des apports de l'amont ; -l'impact est au contraire significatif au niveau des germes, eu égard aux phénomènes de fixation et de concentration des germes dans le "bouchon vaseux" et au niveau du phosphore (qui favorise l'eutrophisation de l'estuaire, et indirectement la désoxygénation). On a conclu : à la nécessité de mettre l'accent sur ces deux derniers paramètres, dans un programme de dépollution plus global intégrant l'ensemble du bassin versant amont de la Loire., Saunier B. M., Buon A., Cabillic P., Clément J. C. Rapport V.10 Incidence du rejet des eaux usées de Nantes Nord sur la qualité des eaux dans l'estuaire de la Loire. In: L'assainissement de demain. L'hydraulique des eaux pluviales et usées. Compte-rendu des XVIIes journées de l'hydraulique. Nantes,14-16 septembre 1982. Tome 2, 1982.