We compiled stable isotope data (2H and 18O) of bulk soil water at five long-term experimental catchments across a hydro-meteorological gradient in the northern latitudes (Figure 1). The comparison of the extensive data set, covering different landscape units at each catchment, showed that vegetation, topography and elevation affect the isotopic composition over time and soil depth. Soil water beneath conifers is more enriched in heavy isotopes than beneath heather or oak vegetation. Sampling sites closer to the stream are generally less variable in their stable isotopic composition than sites at gentle hillslopes. Isotopic fractionation due to soil evaporation was observed mainly in the top 10 to 30 cm and was mainly controlled by the precipitation amount while temperature (as proxy for evaporation) was less important and soil moisture did not influence the isotopic fractionation, as revealed by multiple linear regression. The study will be published (here) in a Special Issue on "Water in the Critical Zone" in Hydrological Processes. The work was funded by the ERC grant VeWa and you can find a presentation by Doerthe Tetzlaff about that project here.
0 Comments
|
Archiv
May 2022
Kategorien
All
|