University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Master / Diploma Thesis:
Lena Campostrini
(2019):
The effects of different DOM-sources on microbial activity in riverine sediments.
Master / Diploma Thesis - Institut für Hydrobiologie, Gewässermanagement (IHG),
BOKU-Universität für Bodenkultur,
pp 61.
UB BOKU
obvsg
- Abstract:
- Agriculture is the dominant land use form in Lower Austria, covering more than 41 % of the total area. Agriculture delivers significant amounts of dissolved organic matter (DOM) to streams, changing basic processes at the water-sediment interface and affecting the ecological state of stream ecosystems. The aim of the project was to investigate the influence of agricultural land use on the quantity and quality of DOM inputs to streams and to examine the effects of these DOM inputs on the aquatic carbon cycling in stream ecosystems. Via in-door flume experiments, we investigated the short-term effects of different DOM sources (extracts from manure, soil from pasture and unfertilized soil) on the growth of benthic microorganisms, the benthic respiration and the activity of extracellular enzymes. The DOM sources were characterised as to their concentrations of dissolved inorganic nutrients as well as to their fluorescence and absorbance characteristics (e.g. SUVA254 and FI in excitation-emission-matrices). As expected, leachates from manure had the highest ammonium and phosphorus contents, but not the greatest effect on bacterial activities. Dissolved organic carbon (DOC) from unfertilized soil was degraded fastest. Bacterial abundances were constantly low throughout the experiments. Notable enzymatic activities were only measured in unfertilized soil leachate samples. From the results it could be concluded that substrates of a more natural, heterogenic composition suggest a higher bioavailability by microorganisms than anthropogenically altered enriched substrates. The results also hint to a possible lack of bioavailable carbon.
- Beurteilende(r): Hein Thomas
- 1.Mitwirkender: Weigelhofer Gabriele