Validation of Cryogenic Vacuum Extraction of Pore Water from Volcanic Soils for Isotopic Analysis
Journal
Water
ISSN
2073-4441
Date Issued
2019
Author(s)
Diego Rivera Salazar
Karen Gutierrez
Walter Valdivia-Cea
Mauricio Zambrano-Bigiarini
Amaya Álvez
Laura Farías
Type
Resource Types::text::journal::journal article
Abstract
<jats:p>Andean headwater catchments are key components of the hydrological cycle, given that they capture moisture, store water and release it for Chilean cities, industry, agriculture, and cities in Chile. However, knowledge about within-Andean catchment processes is far from clear. Most soils in the Andes derive from volcanic ash Andosols and Arenosols presenting high organic matter, high-water retention capacity and fine pores; and are very dry during summer. Despite their importance, there is little research on the hillslope hydrology of Andosols. Environmental isotopes such as Deuterium and 18-O are direct tracers for water and useful on analyzing water-soil interactions. This work explores, for the first time, the efficiency of cryogenic vacuum extraction to remove water from two contrasting soil types (Arenosols, Andosols) at five soil water retention energies (from −1500 to −33 kPa). Two experiments were carried out to analyse the impact of extraction time, and initial water content on the amount of extracted water, while a third experiment tested whether the cryogenic vacuum extraction changed the isotopic ratios after extraction. Minimum extraction times to recover over 90% of water initially in the soil samples were 40–50 min and varied with soil texture. Minimum volume for very dry soils were 0.2 mL (loamy sand) and 1 mL (loam). After extraction, the difference between the isotope standard and the isotopic values after extraction was acceptable. Thus, we recommend this procedure for soils derived from volcanic ashes.</jats:p>
Cite this document
Rivera, D., Gutierrez, K., Valdivia-Cea, W., Zambrano-Bigiarini, M., Godoy-Faúndez, A., Álvez, A., & Farías, L. (2019). Validation of cryogenic vacuum extraction of pore water from volcanic soils for isotopic analysis. Water, 11(11), 2214. https://doi.org/10.3390/w11112214
Subjects
cryogenic vacuum extraction
;
volcanic soils
;
isotopic analysis
;
andes
;
chile
;
catchments
;
cryogenics
;
isotopes
;
runoff
;
soil moisture
;
textures
;
volcanoes
;
cryogenic vacuum
;
environmental isotopes
;
hillslope hydrology
;
initial water contents
;
isotopic analysis
;
soil water retention
;
volcanic soils
;
water-soil interaction
;
catchment
;
deuterium
;
equipment component
;
extraction method
;
hillslope
;
isotopic analysis
;
soil water potential
;
tracer
;
volcanic ash
;
volcanic soil
;
water content
;
water retention
;
water-rock interaction
;
extraction