Changes in streamwater chemistry after 20 years from forested watersheds in New Hampshire, U.S.A.
Bibliographic record
Abstract
Long-term patterns of streamwater chemistry provide valuable evidence of the effects of environmental change on ecosystem biogeochemistry. Observations from old-growth forests may be particularly valuable, because patterns should not be influenced by forest succession. Water samples were collected biweekly from four streams in, and near, the old-growth forest watershed of the Bowl Research Natural Area in the White Mountains of New Hampshire from May 1973 through October 1974, and from June 1994 through June 1997. Average NO3 concentrations, which ranged from 40.8 to 46.1 µequiv.·L-1 in 1973-1974, declined significantly to averages of 14.9-20.1 µequiv.·L-1 during 1994-1997. Concentrations of the base cations, Ca2+ and Mg2+, also declined in stream water between the two sampling periods. The northeastern United States, including the study area, has been subjected to elevated atmospheric deposition of sulfur and nitrogen for more than 40 years. This observation has led to the concern that mature forest ecosystems may exhibit N saturation and depletion of Ca2+ from exchangeable soil pools. While the Bowl exhibits a pattern of elevated concentrations of NO3 throughout the year, suggestive of conditions of N saturation, concentrations have declined markedly over the last 20 years. Concentrations of Ca2+ have also declined suggesting possible depletion from the exchangeable soil pool, but the acid neutralizing capacity of stream water has remained constant or increased, indicating resistance to additional acidification.
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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 | 0.001 |
| 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".