Long-term changes in phytoplankton composition in seven Canadian Shield lakes in response to multiple anthropogenic stressors
Bibliographic record
Abstract
We examined long-term changes in phytoplankton composition from 1981 to 2003 in seven intensively studied lakes on the southern Canadian Shield in Ontario, Canada. Significant (P < 0.05), temporally coherent increases in the relative biovolume of colonial chrysophytes were observed in six of the seven lakes, with coincident declines in the relative biovolume of diatom algae. Variance partitioning analyses identified water chemistry variables, and the co-variation of water chemistry with physicoclimatic variables, as most important in structuring phytoplankton assemblages through time in the study lakes (variance explained: chemical variables (14%–47%, mean = 28.7%); chemistry and physicoclimatic variables (21%–30%, mean = 25.5%)). With the exception of Harp Lake, which was invaded by Bythotrephes in the early 1990s, grazing variables did not explain a significant portion of the phytoplankton variance. We hypothesize that the long-term changes in phytoplankton species composition is attributable to multiple anthropogenic stressors acting at a regional scale. Our results, coupled with paleoecological studies, indicate that increases in the relative importance of colonial chrysophytes are coincident with water chemistry changes associated with industrial activity since the mid-1900s and physical changes linked to climate indices such as the North Atlantic Oscillation.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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".