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Accueil du site > Français > Les annonces de séminaires et thèses > Séminaire de Simon MUDD (School of Geosciences, University of Edinburgh, UK)

Séminaire de Simon MUDD (School of Geosciences, University of Edinburgh, UK)

Date : 7 septembre 2010, 16h

Titre : Feedbacks between vegetation, sea level rise, and sedimentation on salt marshes.

Lieu : Salle de Conférence du CAREN (bât. 14B, RDC)

Résumé : Strong feedbacks exist between sedimentation, sea level rise, and vegetation on coastal salt marshes. Plant productivity is determined, in part, by the elevation of the marsh surface within the tidal frame. This elevation is determined by the rate of sedimentation on the marsh. The sedimentation rate on the marsh is in turn determined by the physical characteristics of marsh vegetation (e.g., stem densities, stem diameters). The physical features and productivity of the marsh grass Spartina alterniflora has been measured monthly at a number of sites at North Inlet, South Carolina, for over 20 years. Using these data, in addition to measurements of sedimentation, we examine the relationships between sedimentation and vegetation in an attempt to produce predictive models of the co-evolution of marsh vegetation and marsh elevation. Using such a numerical model, we investigate the stability of coastal salt marshes like those at North Inlet. As sea level rise accelerates, the marsh surface will move lower in the tidal frame. This will lead to increased plant productivity and sedimentation. But if sea level rise accelerates too quickly, there is a danger that the plants will die and the marsh will drown. The models predict that North Inlet, and marshes like it, will drown in the next century if the worst case scenarios of sea level rise (e.g., Rhamstorf, 2007) prove accurate.