Palaeolimnological assessment of trace element inputs to lakes in the Athabasca Oil Sands Region, Alberta, Canada
Bibliographic record
Abstract
Undisturbed lake sediment records provide a robust natural archive of conditions within \nwaterbodies. They have been used successfully over a number of decades to determine \ntemporal trends of surface water acidification and to follow the effects of eutrophication. \nHowever, lake sediments also provide an archive of changes occurring within lake catchments \nand of atmospheric pollutants deposited onto lake and catchment surfaces. In August 2006, \nparallel lake sediment cores were collected from 22 lakes in the Athabasca Oil Sands Region of \nAlberta by UCL staff as part of the RAMP regional lakes survey. Twelve of these lakes were \nselected for study covering a range of locations from around the Fort McMurray area to sites in \nthe Caribou Mountains and the Canadian Shield. The main aim of this initial study was to \nassess the evidence for lake acidification in the region, but analysis also revealed changes in \nnutrient input and, at one site, mercury (Hg) analysis showed an indication of industrial \ncontamination. This work was reported in Curtis et al. (2010). \nThe analysis undertaken in this initial project was focussed on single radiometrically dated \nsediment cores (hereafter the ‘A’ cores) from each of the 12 selected lakes. The parallel cores \nfrom each lake (the ‘B’ cores) were stored dark, at 4ºC, following their transfer to UCL and \nhence were available for further analysis. Both sediment cores (A and B) from the remaining 10 \nlakes remain unstudied. \nThe aim of this current project was to use the stored ‘B’ sediment cores to assess temporal \ntrends and rates of change in trace element input to a subset of the lakes cored in the \nAthabasca Oil Sands Region of Alberta and compare these with the sediment records of two \nreference lakes in the Caribou Mountains. \nThis interim report contains details of progress on this work up to end March 2012 and a \nsummary of remaining work under this contract. As a consequence this report focusses on data \ncollected so far. Only limited interpretation is provided and will be undertaken fully when the \ndataset is complete. A final report will be produced upon completion of the study.
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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 | 0.003 | 0.003 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".