Many labs benefit from cryogenic water extractions for the analysis of δ2H and δ18O isotopic signatures for different purposes. Some determine plant water uptake depth, others examine soil water movements. Nevertheless, despite the operational use of cryogenic extraction, artifacts leading to uncertain isotopic signatures, and thus, potentially doubtful conclusions, were often observed.
Obtained isotope results imply that extraction conditions (time, temperature, pressure) have to be adapted specifically to the extracted material. However, we lack clear recommendations for standardized extraction conditions. We therefore see an urgent need to rigorously compare results obtained through cryogenic water extraction.
In order to contribute to a method improvement, we plan to develop a standard operating procedure for cryo-lines (with defined extraction times, temperature, and pressure adjusted to different soil types).
For further information contact Natalie Orlowski, who will lead the worldwide interlab comparison project as part of her Postdoc.
We look forward to having you on board!
This project is in cooperation with the Department of Landscape, Water and Biogeochemical Cycles, Prof. Dr. Lutz Breuer, Justus-Liebig-Universtiy Giessen (JLU, Germany) (http://www.uni-giessen.de/cms/faculties/f09/institutes/ilr/ilr-frede).
Brooks, J., R., Barnard, H., R., Coulombe, R. and McDonnell, J., J.: Ecohydrologic separation of water between trees and streams in a Mediterranean climate, Nat. Geosci., 3(2), 100–104, doi:10.1038/ngeo722, 2009. http://www.nature.com/ngeo/journal/v3/n2/abs/ngeo722.html
McDonnell, J. J.: The two water worlds hypothesis: ecohydrological separation of water between streams and trees?, WIREs Water, 1(4), 323–329, doi:10.1002/wat2.1027, 2014. http://wires.wiley.com/WileyCDA/WiresArticle/wisId-WAT21027.html
Orlowski, N., Frede, H.-G., Brüggemann, N. & Breuer, L.: Validation and application of a cryogenic vacuum extraction system for soil and plant water extraction for isotope analysis. J. Sens. Sens. Syst. 2, 179–193, 2013. http://www.j-sens-sens-syst.net/2/179/2013/jsss-2-179-2013.html