Preliminary biogeochemical investigations of small rivers in the Franconian Alb to lay foundations for detailed investigations of turnover and origin of high carbon in the Main River system
Final Report Abstract
The project investigated the rivers Wiesent, Schwabach, Pegnitz for a full hydrological year and also yielded first geochemical insights into the Rivers Aisch, Bucher Landgraben, the Röthelheim Graben and the Muckenbach and the Main River system (including tributaries). Parameters investigated were field measurements (pH, eH, conductivity, dissolved oxygen, alkalinity, temperature) major ions (Ca2+, Mg2+, Na+, Cl-, SO42-, Cl-, PO43-, and NO3-), dissolved and particulate carbon species (DIC, DOC and POC) and their carbon stable isotope compositions as well as stable isotopes of the water. One of the key results of the project was that the rivers investigated showed excessive rates of CO2 de-gassing, despite their large potential of acid buffering in their carbonate dominated catchments. CO2 de-gassing was also associated with a change in the carbon isotope composition of dissolved inorganic carbon (δ13C-DIC) towards more positive values. This can serve as a basis to more precisely determine carbon release to the atmosphere by rivers. The results also form a basis for further investigations in the frame of a Marie Curie fellowship on carbon dynamics in rives of European Karst systems (EuroKarst).
Publications
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2015. Spatial and temporal variations of pCO2, dissolved inorganic carbon, and stable isotopes along a temperate karstic watercourse. Hydrological Processes
van Geldern, R., Schulte, P., Mader, M., Baier, A., Barth, J.A.C.
