Comparing limnological changes associated with 19th century canal construction and other catchment disturbances in four lakes within the Rideau Canal system, Ontario, Canada
Bibliographic record
Abstract
Paleolimnological analysis of microfossils and physical sediment characteristics in 210Pb and Ambrosia dated sediment cores, along with diatom-inferred total phosphorus concentration [TP] reconstructions, were used to determine the trophic histories (ca 200 years) of four lakes within the Rideau Canal system, Ontario, Canada. Paleoecological information of the dominant diatom taxa that flourished during the pre-settlement period indicated that these lakes were naturally oligo-mesotrophic. At the estimated time of canal construction, all lakes demonstrated an increase in nutrients but their responses varied in magnitude. These differences were likely related to a number of variables, but the surface-area:watershed ratio appeared to be an important explanatory variable. Additionally, the similar trophic response of the control lake (not part of the canal), Otter Lake, illustrated the regional impact of past watershed disturbance (e.g. logging, settlement, mining, agriculture), not directly related to canal construction. In more recent years (~1970 to present), less productive planktonic species (e.g. Cyclotella comensis and Cyclotella aff. gordonensis) increased in all the study lakes. These recent water quality changes were attributed to improved nutrient retention of developing soils in secondary growth forests, the potential effects of climate warming, as well as mitigation efforts (e.g. decreased phosphorus concentrations in detergents, etc.). Eutrophication patterns determined for the deeper study lakes were similar to paleolimnological studies of other deep lakes in the canal system. However, the trophic response in the shallow lake, Lower Rideau Lake, is more pronounced at the time of canal construction than those of other shallow canal lake responses (e.g. nearby Lake Opinicon) and suggests that both alternative equilibrium states have occurred. This heightened response was attributed to increased nutrient export in Lower Rideau Lake’s limestone catchment and/or higher watershed disturbance. Finally, results from this study furthers our understanding of impacts in an integrated system of lakes and this information can be used to help set realistic mitigation targets for these and other lakes in the Rideau Canal system.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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".