Isotopic assessment of NO<sub>3</sub><sup>−</sup> and SO<sub>4</sub><sup>2−</sup> mobility during winter in two adjacent watersheds in the Adirondack Mountains, New York
Bibliographic record
Abstract
Biogeochemical cycling of N and S was examined at two watersheds in the Adirondack Mountains, New York, to better understand the retention and loss of these elements during winter and spring snowmelt. We analyzed stable isotope compositions of NO 3 − ( δ 15 N‐NO 3 − , δ 18 O‐NO 3 − ) and SO 4 2− ( δ 34 S‐SO 4 2− , δ 18 O‐SO 4 2− ), along with concentrations and fluxes of NO 3 − and SO 4 2− , in precipitation, throughfall, snowpack, snowmelt, soil water, groundwater, and stream water. Isotopic results showed no evidence of NO 3 − and SO 4 2− transformations in the forest canopy and snowpack; however, markedly decreased δ 18 O values of NO 3 − and SO 4 2− in forest floor water suggest that microbial processing occurred in organic soil horizons. Similarly low δ 18 O values of NO 3 − and SO 4 2− were observed in forest floor and mineral soil leachates, groundwater, and streams. Over the winter observation period, most of the NO 3 − and SO 4 2− in stream water was from a watershed‐derived source, whereas atmospheric contributions were relatively minor. Despite differences in soil water NO 3 − concentrations between watersheds, the isotopic composition of NO 3 − ( δ 15 N‐NO 3 − , δ 18 O‐NO 3 − ) was similar, and indicated that in both watersheds most of the NO 3 − was produced by nitrification in the forest soils. Although there was likely some contribution of SO 4 2− from microbial oxidation of carbon‐bonded sulfur, most of the stream water SO 4 2− appeared to be derived from weathering of S‐containing bedrock or parent material. The decreased δ 18 O values of NO 3 − and SO 4 2− in upper soil horizons indicate that atmospheric deposition of N and S was not directly linked with stream water losses, even during winter and spring snowmelt.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.002 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".