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Gewählte Master / Diploma Thesis:

Gwendal Paget (2014): The importance of flow and flood pulses for the trophic development of altered floodplain systems.
Master / Diploma Thesis - Institut für Hydrobiologie, Gewässermanagement (IHG), BOKU-Universität für Bodenkultur, pp 64. UB BOKU obvsg

Data Source: ZID Abstracts
Abstract:
This study evaluated the effect of flood and flow pulses on the trophic development of several backwaters in the Lobau, an urban floodplain within the city limits of Vienna and a restored floodplain segment, called Orth. Different measurements such as chlorophyll-a, phosphate and nutrient concentrations were used to evaluate the changes in trophic conditions of connected and isolated backwater areas. In order to compare changes in water quality between flooding conditions and normal conditions, additional samples were taken during mean water discharge and data from the monthly monitoring programme sampling were consulted. To investigate the effects on the nutrient release processes in the top layer of the sediments in situ tests with DGT (diffusive gradients in thin films) and DET (diffusive equilibration in thin films) were carried out which provide high resolution profiles (5-10mm) of pore water phosphorus concentrations of the top sediment. Autosampling devices and multiparameter sondes were used to ensure accurate high frequency measurements during periods of floods. During flooding great amounts of nutrients are brought into the floodplains. These additional nutrients can be accumulated in the soil by sedimentation and can be remobilized during times of disconnection or reflooding. This remobilization of nutrients such as phosphorus may lead to a enhanced primary production (eutrophication) in the water body. To quantify the possible risks of additional inputs of nutrients during flooding, the influences of the diverse flood events on the different floodplain segments were analyzed and a possible phosphorus release from the sediment into the water body was investigated comparing pre-and postflooding conditions.

Beurteilende(r): Hein Thomas
1.Mitwirkender: Weigelhofer Gabriele

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