Habitat Specific Growth Rate Adaptation in Oysters During Early Bartonian: Effects of High Temperature and Low Seasonality in the Indian Palaeotropics
Bibliographic record
Abstract
Abstract Seasonally resolved palaeoclimate reconstructions of extreme climatic events, coupled with responses of contemporaneous organisms, offer valuable information for mitigating the future. The tropical position of the Indian subcontinent during the Middle Eocene Climatic Optimum (MECO ∼41 Ma), interrupting a general cooling trend, provides an ideal setting to investigate low‐latitude seasonality under hot climate conditions, considering the modern minimal seasonality in the tropics. To better understand the seasonality and its impact on shallow marine fauna, a high‐resolution multiproxy study is conducted on oyster specimens of the species Flemingostrea pseudoflemingi from the early Bartonian palaeo‐tropical Kutch Basin. Clumped isotope (Δ 47 ) thermometry combined with δ 18 O analyses from excellently preserved shell specimens suggest low seasonal temperature fluctuations (∼3°C) with a mean temperature of 34.4 ± 2.0°C (95% CI) in the warmer season and 31.4 ± 2.4°C in the months of highest rainfall. Oyster populations from distinct regions within the basin display varying sizes. Smaller variants, inhabiting a zone influenced by marine conditions (δ 18 O w : −0.2 ± 0.5‰ to 0.4 ± 1.0‰) experienced slower growth rates (∼18 μm/day) only during the warmer months. In contrast, larger variants, probably residing in a shallower environment prone to larger impact of evaporation and fluvial influence (δ 18 O w : −1.0 ± 0.8‰ to 1.0 ± 0.7‰), maintained a steady growth rate (∼58 μm/day) throughout the year. Although the observed low seasonality is similar to modern tropical settings of the Indian and Pacific Oceans, the significantly warmer temperature range necessitated growth adaptations in oyster populations, as nutrient availability in diverse habitats were critical to their growth.
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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 | 0.000 | 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 | 0.001 |
| 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".