BioGeoChemistry of Tidal Flats


O. Dellwig, M. Grunwald, M. Beck, T. Badewien, A. Lübben, R. Reuter, H. J. Brumsack

Manganese budget of the Spiekeroog backbarrier tidal flat (NW Germany)

Concentrations of dissolved Mn in the North Sea are more than a magnitude higher than in the North Atlantic due to benthic fluxes and riverine input. However, tidal flats gain in importance for the trace metal budgets of the open oceans. At the ICBM a Research Group has been established to study the fundamental processes of the Wadden Sea of NW Germany. One of the research topics is to balance the exchange of dissolved and particulate matter between the tidal flats and the North Sea. Mn signatures of the Wadden Sea water column show clear tidal and seasonal variations for both dissolved and particulate phase. Highest concentrations are observed during low tide in summer due to the contribution of extremely Mn-rich porewaters. During phases of elevated precipitation in fall and winter, freshwater inputs via floodgates become more important. In order to record representative data, a Mn-sensor for continuous measurements will be installed on a time-series station in the Wadden Sea this spring. Along with ADCP and further oceanographic measurements we assume to perform budget calculations for dissolved and particulate Mn.