Paleoecology Of Early–Middle Permian Marine Communities In Eastern Australia: Response To Global Climate Change In the Aftermath Of the Late Paleozoic Ice Age
Bibliographic record
Abstract
Abstract Climate change has exerted a major influence on the biosphere in historical times, altering the geographic range of many species and elevating the extinction risk in both marine and terrestrial realms. This study investigates marine community change during the major early Permian climatic transition from the late Paleozoic ice age to a largely ice-free greenhouse climate. Quantitative counts of fossil abundance from 71 field assemblages and 15 collections from the literature, spanning the early and middle Permian (Sakmarian– Capitanian) of the Tasmania, Sydney, and Bowen basins of eastern Australia document substantial changes in the composition of marine communities during Sakmarian–Kungurian postglacial warming. During the last stages of glaciation (Sakmarian), communities were dominated by the brachiopod Trigonotreta and the bivalve Eurydesma, whereas communities from the later greenhouse climate (Kungurian–Guadalupian) contained abundant productide brachiopods such as Terrakea and Echinalosia. The shift was broadly synchronous at all paleolatitudes within eastern Australia but appears to have occurred first in offshore habitats. Artinskian communities may also have been much more variable than either earlier or later communities. This variability may have been triggered by rapid climate fluctuations, similar to the changes observed in Artinskian tropical terrestrial ecosystems, but it may also stem from sampling a greater number of depositional environments and habitat types. The ultimate fate of the dominant glacial genera differed after they lost dominance, with Eurydesma becoming extinct during climate warming but Trigonotreta persisting at low abundance levels for a much longer time. These results support the theory that climate change most often causes extinctions through indirect paleoecological effects and underscore the important consequences that even gradual, long-term climate change can have in marine ecosystems.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 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".