Michelsen N, van Geldern R, Roßmann Y, Bauer I, Schulz S, Barth J, Schüth C (2018)
Publication Language: English
Publication Type: Journal article, Original article
Subtype: other
Publication year: 2018
Book Volume: 488
Pages Range: 171-179
DOI: 10.1016/j.chemgeo.2018.04.032
Many hydrologic studies require data on the oxygen and hydrogen stable isotope composition (δ18O, δ
precipitation and various collector designs have been suggested for gathering corresponding samples. Yet,
crucial that these collectors, also known as totalizers, prevent evaporation and associated isotope fractionation.
Surprisingly, we were unable to find a comprehensive collector intercomparison in the literature, and much
one that addressed hot and arid conditions.
In this study, we tested six different collector designs over a period of 32 days. They were filled to 20% total volume with water of known isotope composition and placed in a modified laboratory drying oven
low relative humidity (5%) and a diurnal temperature change of 26 to 45 °C. Evaporative mass losses
determined gravimetrically daily while samples for isotope analyses were collected every four days.
The classic Oil collector, featuring a layer of paraffin oil to prevent evaporation, showed the smallest
losses and no detectable isotope shift. The Tube-dip-in-water collector with pressure equilibration tube
performed well, although we noted somewhat larger mass losses and isotope shifts. The latter accounted
0.28‰(Δδ18O) and 0.9‰(Δδ2
H) after 32 days, which is significant, but in view of the extreme conditions,
changes should be still acceptable for most studies. The remaining collectors (Ball-in-funnel, Floating balls,
Float based) all failed.
Under the prevailing conditions, the Tube-dip-in-water collector with pressure equilibration tube seems
represent a good, oil- and thus contamination-free compromise. Nonetheless, also in this system small
cipitation amounts are problematic. This may necessitate modifications of the standard design in terms of
diameter and bottle geometry. We strongly advise researchers to conduct own tests with their intended collector
before field deployment.
APA:
Michelsen, N., van Geldern, R., Roßmann, Y., Bauer, I., Schulz, S., Barth, J., & Schüth, C. (2018). Comparison of precipitation collectors used in isotope hydrology. Chemical Geology (Isotopic Geoscience) Section, 488, 171-179. https://doi.org/10.1016/j.chemgeo.2018.04.032
MLA:
Michelsen, Nils, et al. "Comparison of precipitation collectors used in isotope hydrology." Chemical Geology (Isotopic Geoscience) Section 488 (2018): 171-179.
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