Abstract
Cryogenic vacuum distillation (CVD) is a widely used technique for extracting plant water from stems for isotopic analysis, but concerns about potential isotopic biases have emerged. Here, we leverage the Cavitron centrifugation technique to extract xylem water and compare its isotopic signature to that of CVD-extracted bulk stem water as well as source water. Conducted under field conditions in tropical northern Australia, our study spans seven tree species naturally experiencing a range of water stress levels. Our findings reveal a significant deuterium bias in CVD-extracted bulk stem water when compared to xylem water (median bias −14.9‰), whereas xylem water closely aligned with source water (median offset −1.9‰). We find substantial variations in deuterium bias among the seven tree species (bias ranging from −19.3‰ to −9.1‰), but intriguingly, CVD-induced biases were unrelated to environmental factors such as relative stem water content and predawn leaf water potential. These results imply that inter-specific differences may be driven by anatomical traits rather than tree hydraulic functioning. Additionally, our data highlight the potential to use a site-specific deuterium offset, based on the isotopic signature of local source water, for correcting CVD-induced biases.
| Original language | English |
|---|---|
| Article number | e15099 |
| Pages (from-to) | 1-10 |
| Number of pages | 10 |
| Journal | Hydrological Processes |
| Volume | 38 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Feb 2024 |
Bibliographical note
Funding Information:We acknowledge the Traditional Owners as the custodians of the land in and around Elsey National Park. We thank the Mangarrayi rangers, Elsey National Park rangers and Coodardie cattle station owners for access to sites. This project was funded by CSIRO's Roper River Water Resource Assessment program and a CDU Rainmaker Grant. We thank Sébastien Lamontagne (project design and discussions); Adam Bourke, Diego Alvarez, Bart Edmeades and Jace Emberg (fieldwork); Greg Skrzypek and Douglas Ford (analyses); and Régis Burlett (advice on Cavitron). CD is supported by a fellowship from the Australian Research Council (DE220100852). 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). Open access publishing facilitated by Charles Darwin University, as part of the Wiley - Charles Darwin University agreement via the Council of Australian University Librarians.