Assessing ecohydrological separation in a northern mixed forestbiome using stable isotopes
Bibliographic record
Abstract
Abstract. In recent years, much attention has been paid to the issue of ecohydrological separation during water uptake by vegetation. This has been spurred in part by the two water worlds hypothesis, whereby mobile blue water contributes to groundwater recharge and streamflow generation whereas less mobile green water held in the soil is taken up and transpired by vegetation. This study examines the potential for ecohydrological separation in a northern mixed forest in Ontario, Canada. Stable isotopic compositions of gross precipitation, bulk soil water and xylem water were measured throughout the 2016 growing season for four species: eastern white cedar, eastern hemlock, red oak and eastern white pine. Near-bole soil water contents and mobile soil water isotopic compositions were measured for the last three species. Mobile soil water did not deviate significantly from the local meteoric water line (LMWL); in contrast, both bulk soil water and xylem water deviated significantly from the LMWL, with xylem water significantly depleted in 18O and particularly 2H relative to bulk soil water. Near-surface bulk soil water experienced evaporative enrichment from pre-leaf out to peak leaf out under all tree canopies. There were inter-species differences in displacement of xylem water isotopic compositions from the LMWL and their temporal changes during the growing season, with those of coniferous species becoming isotopically enriched while those of red oak became more depleted in 2H and 18O. These divergences occurred despite thin soil cover (generally
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".