The sediment record of Crawford Lake, Ontario and Derby Lake, Michigan: Anthropogenic modification of diatom communities and paleoclimate reconstructions.
Bibliographic record
Abstract
Annually laminated lake sediments provide detailed records of climatic variability and human activity in a watershed. Laminated lake sediments from Derby Lake, Michigan have been used to reconstruct Holocene climate variability for the last 8,600 years. Using a detailed grayscale record, spectral analysis shows distinct periods of variability centered at ∼250 and 44 years. These periodicities are similar to observed and inferred fluctuations in solar variability, and indicate that solar-climate linkages may be important factors governing regional climate. A sediment record from Crawford Lake, Ontario, Canada, has been used to reconstruct human activity in the watershed for the past ∼1000 years. The Crawford Lake watershed has long been of interest to archaeologists and anthropologists due to settlement by native Iroquois people in the mid 13<super> th</super> century. Detailed fossil diatom assemblages reconstructed from Crawford Lake sediment show that diatom assemblages were extremely susceptible to human activity in the watershed. The diatom flora changed simultaneously with the arrival of humans in the watershed, despite very low numbers of people. The Crawford Lake record is unique in that nearly 400 years of lake recovery separate Iroquoian abandonment of the watershed and resettlement by Canadians in 1867 AD. The diatom flora, combined with a detailed geochemical record, show that despite decreased nutrient availability during this recovery phase, diatoms in Crawford Lake did not return to a pre-disturbance assemblage. Rather, diatoms maintained a meso-eutrophic assemblage throughout the recovery phase. Diatom community structure may be related to hysteresis, or non-linear behavior. The diatom community may have shifted to an alternative stable state following Iroquois village construction, thereby making recovery to pristine assemblages difficult or not possible.
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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 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".