Dissolved organic carbon and nitrogen dynamics in a pristine old growth forested watershed with anthropogenic nitrogen deposition
Bibliographic record
Abstract
Forested watersheds play an important role in the transformation of nitrogen (N) and carbon (C) as they pass from atmospheric inputs to aquatic ecosystems, under diverse anthropogenic nitrogen deposition and land cover regimes. In this study, I examined the transformations of dissolved organic carbon (DOC), ammonium (NH4), nitrate (NO3), and dissolved organic nitrogen (DON) from precipitation inputs through the forest canopy, into the well-drained and wetland soils, and into two streams draining a 46 ha and a 11 ha nested old growth forested watersheds at Mont St. Hilaire (MSH), in southern Quebec. Measurements were made from May to September 2013, with sampling at one-week intervals and during storm events. Concentrations and fluxes of DOC, NH4, and DON increased from the atmosphere to throughfall, and decreased as water passed through the upland mineral soils and wetlands to the stream, while NO3 showed no change. Transformations of DON occurred as water passed through persistently saturated areas within the wetland and surrounding the stream, resulting in biogeochemical hotspots, where DON concentrations significantly decreased. DOC did not respond these locations, yet is positively correlated to DON and increased water depth. Yearly estimated inputs through the forest canopy were 4.04 kg/ha/yr, 5.61 kg/ha/yr, 3.14 kg/ha/yr, and 79.41 kg/ha/yr for NO3, NH4, DON and DOC. Overall, N retention rates from atmospheric input to stream output were 90 % and 91 % for DON and for a combined NO3 and NH4 input-output measure, while DOC inputs were five times greater than outputs. NO3 was retained less during saturated soils conditions and DON showed slightly more retention at the beginning of the growing season. When compared to other studies with low nitrogen, MSH, showed no similarities in retention or output. Studies with high nitrogen deposition and past disturbance did compare with NO3 and NH4 retention results for MSH, however, hydrological DOC inputs-outputs, at MSH, when compared to other high nitrogen sites with anthropogenic disturbance differed, showing five times more DOC input than output, compared to two times more output than input for the disturbed sites. These findings help to define the present day N and C dynamics in an old growth forest with anthropogenic nitrogen deposition, and provide a comparison for future environmental changes and to conservation and natural resource managers during the restoration and protection of forested watersheds.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 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".