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Gewählte Master / Diploma Thesis:

Irene Pilz (2019): Long-term effects of dissolved nutrient and organic carbon loading on the efficiency of in-stream nutrient uptake and metabolic processes.
Master / Diploma Thesis - Institut für Hydrobiologie und Gewässermanagement (IHG), BOKU-Universität für Bodenkultur, pp 68. UB BOKU obvsg FullText

Data Source: ZID Abstracts
Low order streams are very important in terms of reducing nutrient downstream transport by biotic and abiotic nutrient retention. Through the extensive use of organic and inorganic fertilizers in agriculture, natural equilibrium of stream ecosystems between production and decomposition has changed and thus, dramatically affected the self-purification capacity of streams. For an improved management of agricultural streams it is necessary to investigate the effects of a long term enrichment of inorganic and organic fertilizers and how they affect water quality and ecosystem functions. This study was conducted under regulated light and nutrient conditions to understand how epilithic and epipsammic algal and bacterial biomass production and activities including nutrient uptake and decomposition change with continuous nutrient enrichment. We were also interested to find out, at which nutrient concentrations a saturation can be reached, wherefore we conducted our experiment with moderate and high nutrient levels. The experiment lasted over two month including four weeks of colonization phase, four weeks of enrichment phase and two weeks recovery phase. Results have shown, that the chlorophyll-a concentration strongly increased with moderate and high nutrient enrichment but saturation was not reached. Also bacterial biomass did not reach a saturation of biomass production and nutrient uptake. Differences were generally less affected by nutrient enrichment. Furthermore, investigations showed an adaption to enrichment through a higher decomposition of algal cells but also a stimulated decomposition of cellulose compounds. Overall, this study revealed, that biofilms adapt nutrient uptake and metabolic processes in moderate and high enriched flumes probably due to altered structural and functional characteristics. Nevertheless, chosen nutrient levels could not fully cause a saturation.

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

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