Title: Effects of land use and geological composition on nutrient ratios (N, P and Si) and phytoplankton community structure: A case study on Upper Danube River Basin, Austria
Author: H.M. Nurul Islam
Supervising Institution: IHE Delft - Institute for Water Education
The relation between land use and geology in affecting nutrient ratios (nitrogen, phosphorus, and silica) is not well determined. In addition, the presence of hydroelectric reservoirs can affect these ratios due to uptake by phytoplankton. This study tried to find out the influence of geology and land use variations in nutrient concentration and phytoplankton community structure in the headwaters of the Danube River (Austria). Results showed that both geology and land use affect N, P and Si concentrations simultaneously. Higher concentration of N, P and Si associated with phyllite, gneiss, and sand dominated areas as well as with agriculture practices and artificial land cover (p<0.0001). Reservoirs fed by glaciers had less N, P and Si where the main land cover is forests. Around 30% of the variation is explained by geology and land use in the Upper Danube River Basin (UDRB). Phytoplankton results showed that diatoms and green algae are the most dominating phyla in the region, followed by cyanobacteria. PO4-P is the main predictor of primary producers biomass in the alpine reservoirs (p<0.001, r2=0.60). Still, it remains unknown that how these nutrients and their ratios changes phytoplankton community structure in Alps reservoirs.
Keywords: Alps, Geology, Land use, Linkages, Nutrients, Ratios, Phytoplankton, Abundance