Accretion processes on salt marshes in the German Wadden Sea
Accretion processes on salt marshes are governed by various biological and physical parameters. Among the physical driving factors the inundation frequency and inundation height are supposed to be the most important ones. Predicted SLR and a possible increase in storm intensities might therefore change the patterns and rates of sediment accumulation on salt marshes during the coming century.
Salt marsh accretion measurements have been conducted at many sites, especially along the Dutch Wadden Sea in order to obtain long-term series. No such devices are present in the North Frisian Wadden Sea. Hence historic accumulation rates on a foreland marsh on the island of Foehr and on a barrier-connected marsh on the island of Sylt were estimated by means of 210Pb and 137Cs analysis. Additionally, grain size analysis and measurements of organic carbon were conducted. In order to obtain a spatially differentiated picture of the accumulation rates on the marsh, a total of 3 transects, containing 3 cores each, were extracted perpendicular to the shoreline.
The results of these analyses will be used for the validation of a numerical in order to simulate the future evolution of salt marshes in the Northfrisian Wadden Sea under different scenarios of sea level rise and storminess.