Journal Article

FZJ-2015-06171

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Long-term and high-frequency non-destructive monitoring of water stable isotope profiles in an evaporating soil column

Rothfuss, Y. (Corresponding author)FZJ* ; Merz, S.FZJ* ; Vanderborght, J.FZJ* ; Hermes, N.FZJ* ; Weuthen, A.FZJ* ; Pohlmeier, A.FZJ* ; Vereecken, H.FZJ* ; Brüggemann, N.FZJ*

2015
EGU Katlenburg-Lindau

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Please use a persistent id in citations: http://hdl.handle.net/2128/9347  doi:10.5194/hess-19-4067-2015

Abstract: The stable isotope compositions of soil water (δ2H and δ18O) carry important information about the prevailing soil hydrological conditions and for constraining ecosystem water budgets. However, they are highly dynamic, especially during and after precipitation events. In this study, we present an application of a method based on gas-permeable tubing and isotope-specific infrared laser absorption spectroscopy for in situ determination of soil water δ2H and δ18O. We conducted a laboratory experiment where a sand column was initially saturated, exposed to evaporation for a period of 290 days, and finally rewatered. Soil water vapor δ2H and δ18O were measured daily at each of eight available depths. Soil liquid water δ2H and δ18O were inferred from those of the vapor considering thermodynamic equilibrium between liquid and vapor phases in the soil. The experimental setup allowed for following the evolution of soil water δ2H and δ18O profiles with a daily temporal resolution. As the soil dried, we could also show for the first time the increasing influence of the isotopically depleted ambient water vapor on the isotopically enriched liquid water close to the soil surface (i.e., atmospheric invasion). Rewatering at the end of the experiment led to instantaneous resetting of the stable isotope profiles, which could be closely followed with the new method.

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Contributing Institute(s):

1. Agrosphäre (IBG-3)

Research Program(s):

1. 255 - Terrestrial Systems: From Observation to Prediction (POF3-255) (POF3-255)

Appears in the scientific report 2015

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Database coverage:
; ; ; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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