Dynamics of surface elevation and microtopography in different zones of a coastal Phragmites wetland

[Display omitted] •We analyze dynamics of surface morphology with a modified Surface-Elevation Table.•Our study site is a “squeezed” coastal wetland between dykes and rising sea levels.•None of the measuring spots is currently keeping up with local sea-level rise.•Intra-annual variability can mask long-term trends. Surface elevation and microtopography of coastal wetlands are important attributes with respect to the adaptation to sea level change. While the total increase in elevation determines if a wetland can keep up with sea level rise, microtopography impacts, inter alia, hydrological patterns, which again drive surface elevation changes. We analyzed the dynamics of surface morphology during the course of one year at five locations along a transect from land (interior zone) to sea (fringe zone) in a coastal Phragmites wetland at the Darss-Zingst Bodden Chain (Southern Baltic Sea) using a modified Surface-Elevation Table. Landwards this wetland is confined by a dyke while the seaward boundary of the wetland is formed by a micro-cliff. A small strip between the interior and the fringe zone is characterized by small basins (basin zone). Surface elevation changes in the wetland interior are mainly driven by its own productivity. Litter accumulation by the dense Phragmites stands is high, but a combination of high organic sediments and water scarcity led to compaction and counteracted vertical accretion. While the surface elevations of the measurement location in the basin zone and one of the locations in the interior zone remained fairly stable (intra-annual changes