Deep-sea stylasterid <i>δ</i> <sup>18</sup> O and <i>δ</i> <sup>13</sup> C maps inform sampling scheme for paleotemperature reconstructions
Bibliographic record
Abstract
Deep-sea corals have the potential to provide high-resolution paleotemperature records to evaluate oceanographic changes in settings that are vulnerable to current and future ocean warming. The isotopic records preserved in coral skeletal carbonate, however, are limited by their large offsets from isotopic equilibrium with seawater. These “vital effects” are the result of biological influences (kinetic and metabolic) on the calcification of coral skeletons and are well known to drive oxygen and carbon stable isotope ratios ( δ 18 O and δ 13 C, respectively) away from isotopic equilibrium with environmental variables. In this study, two calcitic stylasterid corals ( Errina fissurata ) are sampled via cross sections through their primary growth axes to create skeletal δ 18 O and δ 13 C maps. The maps reveal a consistent trend of increasing isotopic values toward the innermost portion of the cross sections, with minimal spatial change in carbonate mineralogy, the average center values being ∼1 ‰ and ∼3 ‰ closer to seawater δ 18 O and δ 13 C equilibrium values, respectively. We investigate possible mechanisms for these isotopic trends, including potential growth patterns that would drive spatial isotopic trends. Our results highlight the diversity of the stylasterid coral family, and because of our unique sampling strategy, we can prescribe that E. fissurata corals with minimal mineralogical variability be sampled from the center portions of their stems to achieve accurate paleotemperature reconstructions.
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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 | 0.000 |
| 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".