Annual-Scale (1930-1990) Assessment of Anthropogenic Influences on the Assemblage Structure of Golden-Brown Algae (Chrysophytes) in Crawford Lake, Ontario, Canada
Bibliographic record
Abstract
Crawford Lake, situated within the Crawford Lake Conservation Area near Milton, Ontario, Canada, has unique characteristics that make it ideally suited to high-resolution paleoecological studies.The seasonally deposited varved sediments in the deep basin of this meromictic lake are currently being considered as a potential Global Boundary Stratotype Section and Point (GSSP) to mark the lower boundary of the proposed Anthropocene Epoch.Golden-Brown Algae (Chrysophyte) communities were examined at annual resolution in varves spanning 1930-1990 CE from freeze core CRW19-2FT-B2, collected from Crawford Lake in February 2019.Stratigraphically constrained cluster analysis showed major assemblage changes within this interval, with one of the highest magnitude changes occurring between varves deposited in 1952 and 1953, coinciding with the global effect of atmospheric nuclear armament testing on deposited isotope signatures, one of the key markers of the proposed Holocene-Anthropocene boundary.The post-1953 species assemblages within this lake were novel and differed greatly in composition compared to those examined from earlier in the 20 th century.These changes in assemblage are attributed to increased industrial emissions and related effects of acid deposition on the lake's catchment, related to the Great Acceleration -the massive economic, industrial and demographic expansion beginning in the mid-20 th century.The findings reported here reflect major changes in earth systems that the Anthropocene Working Group proposes to use to make the base of the Anthropocene Series, providing support for the laminated sedimentary sequence from Crawford Lake as a potential Anthropocene GSSP.0.070 0.026 0.059 Mallomonas elongata 0.007 0.000 0.000 0.000 0.000 0.000 0.000 0.002 0.000 0.000 0.000 0.000 0.000 0.000 0.002 Synura spinosa 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.002 Synura uvella 0.000 0.000 0.002 0.005 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.005 0.000 Spiniferomonas spp.0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.002 0.000 0.000 0.000 0.000 Chrysosphaerella spp.0.000 0.010 0.000 0.000 0.010 0.000 0.000 0.000 0.000 0.000 0.010 0.165 0.044 0.007 0.126 Mallomonas elongata 0.000 0.002 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.007 0.000 0.005 0.000 0.000 0.000 Synura spinosa 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Synura uvella 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.002 0.090 0.000 0.000 Spiniferomonas spp.0.002 0.000 0.005 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Chrysosphaerella spp.0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.005 0.000 0.000
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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 | 0.002 | 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".