Konferenzposter

Erschienen in: AGU Fall Meeting : San Francisco, 12-16 December 2016

Jahr der Veröffentlichung: 2016

Seiten: H31E-1440-

URL: https://agu.confex.com/agu/fm16/meetingapp.cgi/Paper/131589

Abstract: 

For more than two decades, research groups from around the world have performed cryogenic water extractions for the analysis of ²H and ¹⁸O isotopes of soil water. Here we present results from a worldwide round robin lab intercomparison test. We test the null hypothesis that with identical soils, standards, and isotope analyses, cryogenically extracted stable water isotope across all labs are identical. We shipped 16 laboratories two different standard soils along with reference water of known isotopic composition. Participants oven-dried and rewetted the soils to two different gravimetric water contents with reference water. One batch of soil samples was extracted via predefined extraction conditions common to all laboratories and the second batch via conditions considered routine in the respective laboratory. Extracted water was isotopically analyzed using both a laser spectroscope and a mass spectrometer. Our results indicate large differences among participating laboratories and applied extraction approaches, soil types, and water contents. Mean differences from the added reference water range from 18.1 to -108.4 for δ²H and 11.8 to -14.9 for δ¹⁸O. While recent studies have shown that extraction conditions (time, temperature, vacuum) along with physicochemical soil properties can affect extracted soil water isotope composition, our results show that lab-to-lab differences can be an even greater factor. While the type of cryogenic extraction set-up varied from manifold systems to single chambers, we did not see any clear trends between facility construction and extraction efficiency. Our results generate questions regarding the usefulness of cryogenic extraction as a standard for water extraction since results are difficult to compare across labs. Correction factors for labs to get back to known standards may be one approach, but our preliminary analysis suggests that this may be too complex and too multi-faceted to be useful.

Harvard-Zitierstil: Orlowski, N., Breuer, L. and McDonnell, J. (2016) Worldwide Interlaboratory Comparison of Cryogenic Water Extraction Systems for Soil Water Stable Isotope Analysis [Poster], in AGU Fall Meeting : San Francisco, 12-16 December 2016. AGU. p. H31E-1440. https://agu.confex.com/agu/fm16/meetingapp.cgi/Paper/131589

APA-Zitierstil: Orlowski, N., Breuer, L., & McDonnell, J. (2016). Worldwide Interlaboratory Comparison of Cryogenic Water Extraction Systems for Soil Water Stable Isotope Analysis. In AGU Fall Meeting : San Francisco, 12-16 December 2016. (p. H31E-1440). AGU. https://agu.confex.com/agu/fm16/meetingapp.cgi/Paper/131589