EGU24-5205, updated on 08 Mar 2024
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Late Holocene hydroclimate dynamics in the northern Alps based on compound-specific δ2H from Schliersee, Germany

Maximilian Prochnow1, Katharina Dulias2, Paul Strobel1, Marcel Bliedtner1, Gerhard Daut1, Sönke Szidat3, Gary Salazar3, Sudip Acharya1, Rodrigo Martinez-Abarca2, Anja Schwarz2, Antje Schwalb2, and Roland Zech1
Maximilian Prochnow et al.
  • 1Friedrich Schiller University Jena, Institute for Geography, Physical Geography, Jena, Germany (
  • 2Technische Universität Braunschweig, Institute of Geosystems and Bioindication, Braunschweig, Germany
  • 3University of Bern, Biochemistry and Pharmaceutical Sciences and Oeschger Centre for Climate Change Research, Bern, Switzerland

A comprehensive understanding of Holocene hydroclimate variability in the European Alps remains challenging because of the great spatial and temporal disparities between the northern and southern Alps, mainly caused by changes in atmospheric circulation patterns and different climate settings. Most of the hydroclimate studies are based on lake level and high-resolution flood reconstructions that can be potentially biased by catchment-specific effects and anthropogenic impacts. Moreover, floods are only single events and just one important aspect of paleohydrology. Phases of enhanced evaporation, transpiration and droughts are equally important ecologically and can occur between flooding events. Stable isotopes (δ18O) in speleothems and lake carbonates were applied to track past changes in atmospheric circulation and hydrology, but in the northern Alps, such studies mainly focus on the Late Glacial and Early Holocene.

We present the first compound-specific δ2H record based on terrestrial (n-C31) and aquatic (n-C25) n-alkanes from a sediment core collected from Schliersee, a pre-alpine lake located in Bavaria (Germany), and covering the Late Holocene (past ~4.3 ka). Based on previous calibration studies and new data, we use the δ2H record of n-C31 as a proxy for the isotopic composition of precipitation. We find that δ2Hn-C31 from Schliersee shows depleted values between ~1200 and ~500 cal. yr BP and enriched values before (2500 – 1200 cal. yr BP) and thereafter (500 cal. yr BP until today). This pattern is in good agreement with speleothem δ18O from Spannagel cave, Austria, and compound-specific δ2H from Lake Ghirla, southern Alps and was previously interpreted to reflect changes in moisture source. Therefore, our results support the concept that northern hemispheric cooling and changes in the North Atlantic Oscillation cause changes in moisture source related to shifts in the position of the Westerlies. Based on our results we conclude that this mechanism seem to have affected the isotopic composition of precipitation in both northern and southern Alps.

Moreover, aquatic δ2Hn-C25 is enriched by several tens of permille compared to terrestrial δ2Hn-C31, because of evaporative enrichment of lake water (Grafenstein & Labuhn, 2021 in: Ramstein et al., Springer Cham). Thus, we use their isotopic difference, expressed by Δaq–terr, as a proxy for evaporative enrichment. Our Δaq–terr shows a striking coincidence with tree-ring based drought reconstructions for Europe since the Medieval. This highlights that a “warm and dry” hydroclimate occurred during the Medieval (~1000 cal. yr BP), whereas “cool and wet” conditions prevailed during the Little Ice Age (~600 cal. yr BP). Furthermore, minima in Δaq–terr during the Little Ice Age seem to correspond to minima in solar forcing. High evaporative enrichment coincides with the observed anthropogenic warming during the last 250 years.

Our δ2H-record from Schliersee is consistent with other regional reconstructions and provides additional insights into the paleohydrology of the northern Alps. This highlights the potential of compound-specific δ2H analyses as a powerful tool for paleohydrological reconstructions and helps to better understand the hydroclimate dynamics across the Alps.

How to cite: Prochnow, M., Dulias, K., Strobel, P., Bliedtner, M., Daut, G., Szidat, S., Salazar, G., Acharya, S., Martinez-Abarca, R., Schwarz, A., Schwalb, A., and Zech, R.: Late Holocene hydroclimate dynamics in the northern Alps based on compound-specific δ2H from Schliersee, Germany, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5205,, 2024.