Cultural Eutrophication Trends in Three Southeastern Ontario Lakes: A Paleolimnological Perspective
Bibliographic record
Abstract
Three southeastern Ontario lakes have responded differently to human disturbances in their catchments over the past 150 years. Catchments of Round and Long lakes were once subjected to deforestation and apatite mining but currently have no local watershed disturbances. Meanwhile, Hambly Lake has been surrounded by residences since the 1950s. Subfossil chironomid head capsules and diatom valves were identified and enumerated in sediment cores from Hambly and Round lakes, and diatom remains were analyzed from Long Lake sediments. Quantitative reconstructions for chironomid-inferred average hypolimnetic dissolved oxygen (CIDO) and diatom inferred total phosphorus (DITP) were performed. Paleolimnological data indicated that Round Lake was subject to considerable human impacts in the late-1800s, with a dramatic shift from oligotrophic to mesotrophic and eutrophic diatom taxa and the onset of hypolimnetic anoxia. In the past 60 years (ca. 1945-present), Round Lake reverted to pre-anthropogenic settlement conditions in response to the cessation of human activities in the catchment. Long Lake microfossils revealed similar trends to those recorded in Round Lake, probably due to a similar disturbance history and its close geographic proximity. In contrast to the other two study sites, Hambly Lake was naturally mesotrophic prior to human settlement, and despite the development of numerous cottages and residences in the catchment, only minor shifts to slightly more eutrophic chironomid and diatom assemblages occurred. Higher nutrients and hypolimnetic anoxia appear to be natural conditions, and consequently little additional change occurred after the arrival of European settlers. This study illustrates the importance of obtaining long-term data for identifying background limnological conditions when assessing impacts and developing management plans.
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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 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 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".