EGU22-40
https://doi.org/10.5194/egusphere-egu22-40
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

High-resolution DOC measurements indicate seasonal differences of the contribution of sub-catchments to DOC export 

Katharina Blaurock1, Benjamin S. Gilfedder1, Jan H. Fleckenstein2,3, Stefan Peiffer1, and Luisa Hopp1
Katharina Blaurock et al.
  • 1Department of Hydrology, University of Bayreuth, Bayreuth, Germany
  • 2Department of Hydrogeology, UFZ Helmholtz Centre for Environmental Research, Leipzig, Germany
  • 3Hydrological Modeling Unit, University of Bayreuth, Bayreuth, Germany

Dissolved organic carbon (DOC) is an important link between the terrestrial and aquatic carbon cycle. With regard to climate change, it is important to quantify DOC export from catchments as accurately as possible.  The goal of our study was to investigate the influence of topography on DOC export during different seasons.

We investigated DOC export in a small, forested headwater catchment in the Bavarian Forest National Park, Germany. From April 2020 until June 2021, we measured in-stream DOC concentrations at a 15 minutes interval at three nested sub-catchments using UV-Vis spectrometry. We compared DOC export between the different seasons (winter, snowmelt, wet early summer, wet autumn) and the different locations (two upper steep sub-catchments, one lower flat catchment).

Our results show that DOC export varied strongly between seasons. Whereas DOC export was only 2.3  – 2.7 kg/day/km2 on average in all sub-catchments during winter, it increased to 15.6 – 28.8 kg/day/km2 during the rainy early summer. Snowmelt also contributed to DOC export with 14.9 – 18.7 kg/day/km2 on average and was therefore almost as important as precipitation events in early summer and autumn. During winter and snowmelt, all sub-catchments contributed proportionally to total DOC export compared to their area. However, during the rainy seasons, the upper sub-catchments gained in relative importance leading to a disproportional contribution to total DOC export.

Our high-resolution data allowed us to obtain detailed quantities of DOC export over a long period covering different hydrological seasons. These numbers can help us to better understand the importance of DOC export during different seasons. Moreover, our results show that DOC export can vary strongly between small sub-catchments due to the importance of different hydrological processes. This finding is especially relevant as the number of drought periods and extreme rain events will increase and therefore not only influence the distribution of DOC export during the year but also have an impact on the contribution of different sub-catchments.

How to cite: Blaurock, K., Gilfedder, B. S., Fleckenstein, J. H., Peiffer, S., and Hopp, L.: High-resolution DOC measurements indicate seasonal differences of the contribution of sub-catchments to DOC export , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-40, https://doi.org/10.5194/egusphere-egu22-40, 2022.

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