Bibliographic record
Abstract
Ombrotrophic peatlands are nutrient-deficient systems and important carbon (C) sinks, yet the stoichiometry of nitrogen (N), phosphorus (P) and potassium (K), essential for plant growth and decomposition, has rarely been studied in these systems. Under contemporary anthropogenic environmental changes, such as enhanced atmospheric deposition, the balance among multiple elements during ecological processes and interactions, i.e. ecological stoichiometry, is altered. The stoichiometry in plants and soils in peatlands and the response of these stoichiometric characteristics to nutrient enrichment are critical in a world of elemental imbalance between organisms and their environment. The objectives of this research were to examine the seasonal variation in C:N:P:K stoichiometry among different plant functional types (PFTs), the effects of nutrient addition on nutrient resorption and the degree of stoichiometric homeostasis, and the decomposition cascade of C:N:P stoichiometry from mature tissues to peat at Mer Bleue Bog, eastern Ontario, Canada. Along with a greater variation in nutrient concentrations and stoichiometric ratios among PFTs than across the growing season, a convergence of C:N:P:K to a mass ratio of 445:14:1:9 was found at peak growing season, indicating N and P co-limitation. A substantial resorption of N, P and K during leave senescence was observed and was significantly different between the two dominant shrub species, Chamaedaphne calyculata and Rhododendron groenlandicum. The interaction between N, P and K addition on their resorption reflected the stoichiometric coupling of nutrient cycling. In response to long-term N, P and K fertilization, shrubs and mosses showed strong and weak homeostasis, respectively; whereas the dominance of shrubs with strong homeostasis did not enhance the stability or the productivity of the plant community. The examination of the decomposition cascade of C:N:P stoichiometry confirmed the resorption-associated decrease in C:N and C:P ratios from mature to senescent tissues. A possible mechanism related to plant/mycorrhizae uptake of P may account for the increase in C:P and N:P ratios in peat. This thesis contributes new knowledge on the stoichiometry of plants and soils in an ombrotrophic peatland. Specifically, it emphasizes the important role of P in peatland biogeochemical cycles, especially the plant and mycorrhizal uptake of P in these nutrient-deficient ecosystems. The substantial variation in nutrient resorption and stoichiometric homeostasis between species and among PFTs shed new light on the potential shifts in plant community composition under environmental changes.
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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 | 0.000 |
| 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".