Chironomid assemblages in surface sediments from 182 lakes across New England and Eastern Canada: Development and validation of a new summer temperature transfer function
Bibliographic record
Abstract
This study investigates the distribution of subfossil chironomid assemblages in surface sediments from 182 lakes in New England and Eastern Canada, aiming to develop a new summer paleotemperature transfer function across an extended latitudinal gradient. Canonical analyses reveal a strong empirical relationship between chironomid taxa and summer temperatures, highlighting both direct physiological constraints and indirect environmental interactions. These results emphasize the importance of ecological assessments in interpreting subfossil records to verify the prominent role of summer temperature in driving assemblage changes. Two inference models for mean summer air temperature are developed: one using the commonly employed weighted averaging partial least squares (WAPLS) and another with the newly introduced frequency-corrected tolerance-weighted WAPLS (fxTWAPLS). Both cross-validation and independent assessments using downcore data against meteorological measurements confirm that subfossil chironomids are overall reliable proxies for summer temperatures. The fxTWAPLS model demonstrates superior reconstruction performance by effectively addressing the compression bias inherent in classical WAPLS. New inference models are applied on an existing postglacial record from the eastern Canadian boreal forest. The reconstruction is improved by the greater availability of warm modern analogues, allowing for the clear identification of the warm Mid-Holocene and the subsequent Neoglacial cooling, as well as a warming episode possibly related to the Roman Warm Period. The fxTWAPLS model further improves the reconstruction by inferring a wider range of temperatures, with both colder and warmer periods than modern conditions. This transfer function constitutes a new valuable operational tool for producing high-quality paleoclimatic reconstructions of Late-Quaternary summers in the Nearctic region. • New Nearctic chironomid training-set covering a broad temperature gradient. • Modern chironomid distribution is strongly linked to mean summer air temperature. • Limnological features can influence taxon responses to summer air temperature. • The fxTWAPLS method yields more accurate inferences than WAPLS. • The new transfer function enhances a postglacial temperature reconstruction.
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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 | 0.000 |
| 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".