Effects of water depth and water level fluctuation on the total and bio-available element concentrations in riverine reed stands

Abstract

• Chemical composition in riverine reed stands depends on water depth and water level fluctuation. • Both the total and the bio-available element concentrations increase towards the deep water. • Floods homogenize the surface layer of the sediment, but water depth gradient influences the bio-available fractions. • Chemistry in reed stands can indicate redox conditions in the rhizosphere and anthropogenic pollution sources. This paper evaluates the chemical composition of reed stands grown in different riverine habitats. In addition to the total concentrations, we first present data on the bio-available element fractions of the sediment of reed stands. The results demonstrate clear separation between the plant and sediment samples and reveal the same concentration order of organs in all of the investigated sites irrespective of the water depth and water level fluctuation of the habitats. In reed stands with static water depth gradient, both the total and the bio-available element concentrations of the sediment increase towards the deep water. In habitats regularly flooded by the river, the deposition of suspended matter homogenizes the surface layer of the sediment and, therefore, total element concentrations in that layer is not influenced by the deepening river bed. After the flood event, however, the water depth gradient does influence the bio-available fractions. Finally, it is also demonstrated that chemistry in reed stands can indicate redox conditions in the rhizosphere and anthropogenic pollution sources.