Effects of long-term nitrogen and sulfur deposition on soil microbial communities and soil properties in the Athabasca oil sands region in northern Alberta, Canada
Bibliographic record
Abstract
Intensified oil sands activities have resulted in elevated levels of nitrogen (N) and sulfur (S) deposition in the mixedwood boreal forest in the Athabasca oil sands region (AOSR) of northern Alberta, Canada. The deposition of N and S can affect the surrounding ecosystem and it is important to monitor possible effects. To improve the understanding of the response of boreal forest ecosystems to increased N and S deposition in the AOSR, an experiment was established in 2006 with the following treatments: control, +N addition (30 kg N ha-1 yr-1 as NH4NO3), +S addition (30 kg S ha-1 yr-1 as Na2SO4), and +NS addition (30 kg N plus 30 kg S ha-1 yr-1). Nine years of simulated N and S deposition did not affect soil bacterial diversity, community composition, abundance, functional profiles, and co-occurrence patterns, suggesting that soil bacteria were resistant or resilient to increases in N and S addition in the studied boreal forest. In contrast, increased N and S addition increased the abundance of soil fungal communities, suggesting fungi were more sensitive than soil bacteria. Additionally, ten years of simulated N and S deposition did not change soil chemical properties including soil pH, cation and N concentrations and leaching of N below the main rooting zone. Therefore, there was no evidence of N saturation or soil acidification in the experimental forest ecosystem in the AOSR after ten years of N and S addition. Continued long term research of N and S deposition in the AOSR is needed to enhance the current level of understanding and to quantify the collective ecosystem impacts.
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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 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 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".