Abstract
The analysis of the stable isotopic composition of hydrogen and oxygen in water samples from soils and plants can help to identify sources of vegetation water uptake. This approach requires that the heterogeneous nature of plant and soil matrices is carefully accounted for during experimental design, sample collection, water extraction and analyses. The comparability and shortcomings of the different methods for extracting water and analyzing isotopic composition have been discussed in specialized literature. Yet, despite insightful comparisons of extraction methods and benchmarking methodologies of laboratories worldwide, the community still lacks a roadmap to guide sample collection, extraction, and isotopic analyses, and many practical issues for potential users remain unresolved: for example, which (soil or plant) water pool(s) does the extracted water represent? These constitute a hurdle for the implementation of the approach by newcomers. Here, we summarize discussions led in the framework of the COST Action WATSON (“WATer isotopeS in the critical zONe: from groundwater recharge to plant transpiration”—CA19120). We provide guidelines for (1) sampling soil and plant material for isotopic analysis, (2) methods for laboratory or in situ water extraction, and (3) measurements of isotopic composition. We highlight the importance of considering the process chain as a whole, from experimental design to isotopic analysis to minimize biased estimates of the relative contribution of different water sources to plant water uptake. We conclude by acknowledging some of the limitations of this methodology and advice on the collection of key environmental parameters prior to sample collection for isotopic analyses.
Original language | English |
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Article number | e1727 |
Number of pages | 33 |
Journal | WIREs Water |
Early online date | 5 Mar 2024 |
DOIs | |
Publication status | E-pub ahead of print - 5 Mar 2024 |
Bibliographical note
The idea of the review paper developed during online and in-person meetings of the WATSON (WATer isotopeS in the critical zONe from groundwater recharge to plant transpiration) COST Action (CA19120; www.cost.eu). We thank Prof. Hans Schnyer for his advice on sampling nonwoody plant species for analyses of water isotopic composition. The graphical abstract was created with BioRender.com. Open Access funding enabled and organized by Projekt DEAL.FUNDING INFORMATION
This study was financially supported by the COST Action: “WATSON” CA19120 (www.cost.eu). TEG received funding from the Spanish Ministry of Science (grant PHLISCO, PID2019-107817RB-I00) and the Generalitat de Catalunya (SGR-Cat 2021 00849). AB acknowledges a Beatriu de Pinós MSCA-COFUND postdoctoral grant from the Government of Catalonia (2019BP00193) and funding from the Spanish Ministry of Science (Grant MICROCLIM, PID2020-117636GB-C21). JR was funded by the Austrian Academy of Sciences or ÖAW (ClimGrassHydro) and by the Tyrolean Science Fund or TWF (F. 33,781/9-2021). MML was funded by the Swiss National Science Foundation (grant no. 213367).