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Accueil du site > Français > Les annonces de séminaires et thèses > Séminaire de Christian GRIEBLER (Helmholtz Center, Munich)

Séminaire de Christian GRIEBLER (Helmholtz Center, Munich)

Date : 17 septembre 2008, 14h30

Titre : Attempts for an integrative (ecological) assessment of groundwater ecosystems ­microbes as possible bioindicators.

Lieu : salle de conférences du CAREN (bât 14B RDC)

Résumé : Healthy aquifers deliver important ecosystem services, e.g. the purification of infiltrating water and the storage of high quality water over decades in significant quantities. Also the functioning of terrestrial and surface aquatic ecosystems directly depends on groundwater and /vice versa/. Nowadays, legislation in many parts of the world has started to consider groundwater not only as a resource but as a living ecosystem. To our opinion, the assessment of ecosystems requires consideration of ecological criteria. So far, such criteria are not available for groundwater systems. In the framework of a project supported by the German Federal Environment Agency (UBA), a first concept for the ecological assessment of groundwater ecosystems is developed, with a strong focus on microbes as potential bioindicators. The various steps concept development, including (i) the typology of groundwater ecosystems from an ecological point of view, (ii) the derivation of natural background and threshold values, (iii) the identification of potential bioindicators, and finally (iv) the merging of these information into an assessment model. Successes and difficulties associated with these challenges, e.g. the lack of simple correlations between abiotic and biotic variables in groundwater ecosystems, are discussed on the basis of two data sets from two different groundwater landscapes in Germany, /i.e./ the sands and gravels of the Lower Rhine (Rur- and Erftmassif in the Kölner Bucht) and karstic limestone of the alpine region (Swaebian Alb), each distinguished into a local and a regional aquifer. The need for collaboration between ecologists, microbiologists, hydrogeologists and geochemists, for the successful derivation of integrative, ecological criteria, as well as the application of multivariate statistics, is emphasized.