EGU23-3305, updated on 02 May 2023
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Anthropogenic activities significantly increase annual greenhouse gas (GHG) fluxes from temperate streams, rivers, and drainage ditches in Germany

Ricky Mwanake1, Gretchen Gettel2,7, Elizabeth Wangari1, Clarissa Glaser3, Tobias Houska4, Lutz Breuer4,5, Klaus Butterbach-bahl1,6, and Ralf Kiese1
Ricky Mwanake et al.
  • 1KIT Campus Alpin - IMK-IFU, Terrestrial Bio-Geo-Chemistry, Germany (
  • 2IHE-Delft Institute for Water Education, Westvest 7 2611 AX Delft the Netherlands
  • 3Center for Applied Geoscience, University of Tübingen, Tübingen, Germany
  • 4Institute for Landscape Ecology and Resources Management (ILR), Research Centre for BioSystems, land use / land cover and Nutrition (iFZ), Justus Liebig University Giessen, Giessen, 35392, Germany
  • 5Centre for International Development and Environmental Research (ZEU), Justus Liebig University Giessen, Senckenbergstrasse 3, 35390 Giessen, Germany
  • 6Pioneer Center Land-CRAFT, Department of Agroecology, University of Aarhus, Denmark
  • 7Department of Ecoscience, Lake Ecology, University of Aarhus, Denmark

Anthropogenic activities increase the contributions of inland waters to global greenhouse gas (GHG; CO2, CH4, and N2O) budgets, yet the mechanisms driving these increases are still not well constrained. In this study, we quantified year-long GHG concentrations and fluxes, as well as water physico-chemical variables from 23 streams, three ditches, and two wastewater inflow sites across five catchments in Germany contrasted by land use. Using mixed-effects models, we determined the overall impact of land use and seasonality on the intra-annual variabilities of these parameters. We found that land use was more significant than seasonality in controlling the intra-annual variability of GHG concentrations and fluxes. Agricultural land use and wastewater inflows in settlement areas resulted in elevated riverine CO2, CH4, and N2O emissions, as substrate inputs by these sources appeared to favor in situ GHG production processes. Dissolved GHG inputs directly from agricultural runoff and waste-water inputs also contributed substantially to the annual emissions from these sites. Drainage ditches were hotspots for CO2 and CH4 fluxes due to high dissolved organic matter concentrations, which appeared to favor in situ production via respiration and methanogensis. Overall, the annual emission from anthropogenic-influenced streams and rivers in CO2-equivalents was up to 20 times higher (~71 kg CO2 m-2 yr-1) than from natural streams (~3 kg CO2 m-2 yr-1). Future studies aiming to estimate the contribution of riverine systems to GHG emissions should therefore focus on anthropogenically perturbed streams, as their GHG emission are much more variable in space and time.

How to cite: Mwanake, R., Gettel, G., Wangari, E., Glaser, C., Houska, T., Breuer, L., Butterbach-bahl, K., and Kiese, R.: Anthropogenic activities significantly increase annual greenhouse gas (GHG) fluxes from temperate streams, rivers, and drainage ditches in Germany, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-3305,, 2023.