Comparison of precipitation collectors used in isotope hydrology

Beitrag in einer Fachzeitschrift
(Originalarbeit)


Details zur Publikation

Autor(en): Michelsen N, van Geldern R, Roßmann Y, Bauer I, Schulz S, Barth J, Schüth C
Zeitschrift: Chemical Geology (Isotopic Geoscience) Section
Jahr der Veröffentlichung: 2018
Band: 488
Seitenbereich: 171-179
ISSN: 0168-9622
Sprache: Englisch


Abstract

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.


FAU-Autoren / FAU-Herausgeber

Barth, Johannes Prof.
Lehrstuhl für Angewandte Geologie
van Geldern, Robert PD Dr.
Lehrstuhl für Angewandte Geologie


Zusätzliche Organisationseinheit(en)
Lehrstuhl für Angewandte Geologie


Zitierweisen

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://dx.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.

BibTeX: 

Zuletzt aktualisiert 2019-03-01 um 13:10