Transformation processes of redox sensitive trace metals in the water column and sediments of temperate tidal systems Tidal flats represent the transition zone between the terrestrial and marine realm. They are subject to pronounced dynamics due to distinct tidal and seasonal variations of physical chemical and biological parameters significantly influencing redox sensitive element cycles. Thus redox sensitive trace metals may be suitable indicators for variations in bioproductivity and microbial activity. Therefore seasonal and tidal dynamics of manganese iron molybdenum uranium and vanadium were studied in the water column and sediments of tidal systems of the German Wadden Sea (southern North Sea) in the years 2007 to 2009 involving also previously analysed data from year 2002. To demonstrate the response of the trace metal cycles on phytoplankton blooms and enhanced biological activity time series data of nutrients and phytoplankton dynamics were also involved in this study. Pronounced cycling is seen for pelagic manganese revealing distinctly higher values during low tide. Complex seasonal cycling showing maxima of dissolved manganese in spring and late summer and a depletion period in early summer is caused by benthic pelagic coupling and reflection of exhaustion and replenishing periods in the surface sediments. Vanadium dynamics are coupled to the manganese cycling due to vanadium scavenging and release during manganese oxide formation and reduction respectively. Molybdenum and uranium behave almost conservatively following changes in ... Geochemie Mangan Molybdän Watt Nordsee <Süd> redox sensitive trace metals phytoplankton nutrients water column sediment