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A new method to estimate the biodegradation potential of S-metolachlorin a constructed wetland (ZTHA, Bray) was developed. For that propose, batch experiments were performed with sediments collected from ZTHA. The half life of S-metolachlor was determined under biotic and abiotic conditions (sterile microcosms), aerobic and anoxic conditions and in the presence of different carbon sources (crush plants or acetate). One assay was performed without any carbon source. The results suggest that the S-metolachlor degradation is a biotic phenomenon because it seems to be catalyzed by microorganisms. There is a significant decrease of the half lives in the biotic microcosm (15.5 days in the case of the aerobic microcosm and 20.5 days in the anoxic) comparing to the sterile microcosms (60.2 days in the case of the aerobic and 45.5 days in the anoxic) (P; En cherchant à évaluer le potentiel de dégradation du S-métolachlore dans la zone tampon humide artificielle (ZTHA) de Bray, Nous avons développé un protocole de suivi de dégradation en microcosmes à partir des échantillons prélevées de la ZTHA. La demie vie du S-métolachlore a été déterminé en conditions biotiques et abiotiques (microcosmes stérilisées) et en fonction de différents paramètres d’oxydoréduction (aérobie/ anoxie), et de sources de carbone complémentaires (plantes broyées / acétate/ sans source complémentaire). Les résultats suggèrent que la dégradation du S-métolachlore est catalysée par la présence des microorganismes (phénomènes biotiques) car nous observons une diminution significative de la demi-vie dans ces microcosmes (15,5 aérobie et 20,5 anoxie) par rapport aux microcosmes stérilisés (60,2 aérobie et 45.5 anoxie) (P

One of the key actions identified by the Water Framework Directive (WFD; 2000/60/EC) is to develop ecological assessment tools and carry out a European intercalibration (IC) exercise. The aim of the Intercalibration is to ensure that the values assigned by each Member State to the good ecological class boundaries are consistent with the Directive’s generic description of these boundaries and comparable to the boundaries proposed by other MS. In total, 83 lake assessment methods were submitted for the 2nd phase of the WFD intercalibration (2008-2012) and 62 intercalibrated and included in the EC Decision on Intercalibration (EC 2013). The intercalibration was carried out in the 13 Lake Geographical Intercalibration Groups according to the ecoregion and biological quality element. In this report we describe how the intercalibration exercise has been carried out in the Mediterranean Lake Phytoplankton group.

International audience; Anaerobic digestion makes it possible to valorize municipal solid waste (MSW) into biogas and digestate which are, respectively, a renewable energy source and an organic amendment for soil. Phenols are persistent pollutants present in MSW that can inhibit the anaerobic digestion process and have a toxic effect on microbiota if they are applied to soil together with digestate. It is then important to define the operational conditions of anaerobic digestion which allow the complete degradation of phenol. In this context, the fate of phenol during the anaerobic digestion of MSW at 55 °C was followed using an isotopic tracing approach (13C6-phenol) in experimental microcosms with inoculum from an industrial thermophilic anaerobic digester. With this approach, it was possible to demonstrate the complete phenol biodegradation into methane and carbon dioxide via benzoate.

13th World Congress on Anaerobic Digestion : Recovering (bio) Ressources for the World, Santiago de Compostella, ESP, 25-/06/2013 - 28/06/2013; International audience; Anaerobic degradation requires a complex network of interacting and competing microorganisms. Waste anaerobic digesters are based on the intensive use of this flora. Consequently, functioning and stability of digesters are directly related to microbial populations' dynamics. The latter may be subject to external disturbances, such as the arrival of micropollutants with waste, causing malfunction of bioprocesses. In this context, we questioned the influence of phenol addition on microbial communities degrading cellulose under anaerobic conditions. For that purpose, cellulose batch digesters were set-up and inoculated with municipal solid waste digester sludge. Modifications of microbial dynamics and degradation performances after addition of phenol were evaluated in triplicates (nine different concentrations tested, from 0 to 4g.L-1). Gas production, reaction pathways and phenol concentration were followed over time. These results were linked to the monitoring of microorganisms' dynamics (automated-ribosomal-intergenic-spacer-analysis method, ARISA and qPCR on functional gene and on total Archaea and Bacteria) and of their spatial organisation (fluorescent-in-situ-hybridization, FISH). With increasing phenol concentrations, increasing disruption of digesters' performances (gas production, intermediates accumulation) was observed. EC50 (half-maximal effective-concentration) values for phenol was calculated from the dose/effect curve obtained by plotting degradation parameters as a function of phenol concentration. With increasing concentration, intermediates pathways were modified; Archaea activity was totally inhibited from 1.5g.L-1, Bacteria activity from 2.0g.L-1. Moreover, phenol degradation was observed in several digesters after several weeks. ARISA monitoring revealed an important influence of phenol concentration on microbial dynamics in general. qPCR gave more specific information. Physico-chemical and microbial results were linked to establish patterns of communities' perturbation by phenol. A phenol inhibition threshold was established for several microorganisms. Subdominant microorganisms that used phenol perturbation to settle and phenol degrading microorganisms were identified. This study gives important insights in the understanding of micropollutants effect on complex microbial communities' dynamics and their influence on digesters' stability.

Sampling, analysis and counting of phytoplankton has been undertaken in European lakes for more than 100 years (Apstein 1892, Lauterborn 1896, Lemmermann 1903, Woloszynska 1912, Nygaard 1949). Since this early period of pioneers, there has been progress in the methods used to sample, fix, store and analyse phytoplankton. The aim of the deliverable D3.1-4 is to select, harmonize and recommend the most optimal method as a basis for lake assessment. We do not report and review the huge number of European national methods or other published manuals for phytoplankton sampling and analysis that are available.

Meeting of SWS/WETPOL and Biogeochemistry symposium, Prague, CZE, 03-/07/2011 - 08/07/2011; International audience; A new method to estimate the biodegradation potential of S-metolachlor, in an artificial wetland ecosystem (AWE) in Bray, France, was developed. For that propose, batch experiments were performed with sediments collected from AWE. The half-life of S-metolachlor was determined under biotic and abiotic conditions (sterile microcosms), aerobic and anoxic conditions and in the presence of different carbon sources (crush plants or acetate). One assay was performed without any carbon source. The results suggest that the S-metolachlor degradation is a biotic phenomenon catalyzed by microorganisms. There is a significant decrease of the half-lives in the biotic microcosm (15.5 days in the case of the aerobic microcosm and 20.5 days in the anoxic) comparing to the sterile microcosms (60.2 days in the case of the aerobic and 45.5 days in the anoxic) (P

International audience; Diversity of phytoplankton is expected to decrease with eutrophication. This may serve for a biological indicator.