From a landscape perspective, it is less known how the connectivity of lakes to other fluvial systems in the hydrological continuum affects biogeochemical processes. Masumi Stadler investigated this in her master thesis with the title “Spatio-seasonal variability in dissolved organic matter optical properties and reactivity in a sub-alpine lake” under supervision of Martin Kainz and co-supervision of Elisabet Ejarque-Gonzalez. In July Masumi Stadler successfully finished her thesis. Congratulations!
In freshwater systems, dissolved organic matter (DOM) mainly originates from terrestrial and aquatic primary production, respectively, and its biodegradability is expected to vary due to differences in their biochemical composition. Still, the interaction of DOM of differing origin and the aquatic microbial population remains widely debated. Furthermore, how much carbon is retained in the lake system or exported to connected fluvial systems ultimately affects our understanding of the global carbon cycling. To address these questions, changes in DOM biodegradability and the consequent growth of microorganisms were assessed in dark bioassays for 20 days along a stream-lake continuum over four seasons. PARAFAC analysis modelled six components, of which three correspond to humic- and fulvic-like and the remaining three to protein-like fluorophores. Protein-like components comprised more than 50% of the relative proportion in the lake epilimnion in spring and summer, while the humic-like proportion was highest in the inflow with a cumulative fraction up to 85% in summer. Despite its high optical allochthonous DOM signature and lowest initial abundance, highest microbial growth rates were observed in the inflow (0.0076 ± 0.0011 cells mL-1 h-1) across all seasons. DOM reactivity differed rather in seasons than sites and DOM compositional differences show higher lability of DOM in upper lake layers but not in the outflow. Thus, a clear upgrading effect of DOM to downstream systems was not found, however, our results highlight the potential of terrestrially-derived DOM to be processed and incorporated by bacteria. This observation challenges previous ideas that DOM of terrestrial origin is less accessible and recalcitrant, while emphasising the flexible response of aquatic systems to seasonal fluctuations.
The research-education-cooperation „Wasser und MeHr“ won the award as best project at the Lower Austrian Science Fair this year. The BRG Waidhofen/Ybbs (secondary school) applied under direction of Mag. Rainer Reschenhofer and Mag. Jakobus Sales-Reichartzeder together with WasserCluster Lunz, other project partners were the municipality of Waidhofen/Ybbs and the company Messtechnik. The BRG Waidhofen/Ybbs is project partner of WasserCluster for several years now and supported successfully the collection of data for some of our research projects. The award is handed over at the science gala of Lower Austria in Grafenegg at October 5th 2017. Congratulations!
On June 22nd the NFB (Lower Austrian Research and Education) presented the projects of the Science and Life Science Calls 2015 selected by a jury in the Vierzigerhof in Langenlois. The WasserCluster Project ORCA (Organic carbon; www.organic-carbon.at) was presented with a short movie and a presentation.
In June 128 young scientists were awarded by the Austrian Academy of Sciences (ÖAW) and the Max Kade-Foundation for their highly qualified projects – among them WasserCluster researcher Dunja Lukic. She received a DOC fellowship to carry out her PhD research under the supervision of Zsófia Horváth and Robert Ptacnik. Congratulations!
The master thesis of Marina Jecmenica investigates the potential of poultry by-product meal as potential fish meal replacement in diets of a hybrid charr (S. alpinus X fontinalis), frequently raised in freshwater aquaculture in and around the European Alps. Marina Jecmenica successfully finished her master thesis under supervision of Martin Kainz in April.
Lakes, rivers, estuaries and oceans are closely connected. Despite this, aquatic research is still divided in marine and freshwater sciences. Now scientists from 21 leading research institutes and universities and two enterprises from 12 countries across Europe - among them WasserCluster Lunz - aim to change this and have joined forces in the project “AQUACOSM - Network of Leading European AQUAtic MesoCOSM Facilities Connecting Mountains to Oceans from the Arctic to the Mediterranean”.
WasserCluster researcher Csaba Vad investigated the diversity of animals in bomb craters from World War 2. He found out, that they are a home to rare and vulnerable animals. This results were in the headlines from newscientist.com to natureworldnews.com.
Our intern Isabell Aigner got an award for her internship report from the Austrian Research Promotion Agency (FFG) and the ministry BMVIT. Together with her internship tutor, our technical assistant Beate Pitzl, he was invited at the award ceremony in the Urania Vienna.