A multi-proxy peat study of Holocene vegetation history, bog development, and carbon accumulation on northern Vancouver Island, Pacific coast of Canada
Bibliographic record
Abstract
We present a multi-proxy paleoenvironmental study on a 10,400 cal. yr peat sequence from an ombrotrophic bog in coastal British Columbia, Canada. Pollen, non-pollen palynomorph, plant macrofossil, and physicochemical analyses (bulk density, %C, %N, δ 13 C, and δ 15 N isotopes) were used to document changes in vegetation, bog development, and carbon and nitrogen accumulation. Pollen assemblages indicate that regional vegetation in the warm, relatively dry early Holocene was mixed coniferous forest with scattered Pseudotsuga menziesii. Herbaceous peat with a C:N of ~28, combined with Nuphar microfossils and relatively high %N, suggests the presence of a herb-dominated peatland with standing water and/or bog pools. Carbon and nitrogen accumulation were at their highest during this early Holocene period at mean rates of 30.6 and 1.2 g/m 2 /cal. yr, respectively. By 8000 cal. yr BP and under a cooler, wetter climate, northern Vancouver Island supported Tsuga heterophylla rainforest similar to today. Decreasing relative water table, inferred from testate amoebae and fungal remains, facilitated the establishment of a Sphagnum bog by 8000 cal. yr BP with abundant ericaceous shrubs after 5000 cal. yr BP. Temporal variation in carbon accumulation rates corresponds with changes in plant functional types and hydrological conditions: rates were lowest in the early to mid-Holocene during accumulation of Sphagnum peat (7.1 g/m 2 /cal. yr) and increased in late Holocene ligneous peat (12.4 g/m 2 /cal. yr). Our multi-proxy approach not only demonstrates the overarching control of climate on bog development and carbon and nitrogen accumulation, with seasonality likely playing a major role, but also highlights the strong influence of autogenic processes at a local scale.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 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 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".