Climate-modulated nutrient conditions along the Labrador Shelf: Evidence from nitrogen isotopes in a six-hundred-year-old crustose coralline alga
Bibliographic record
Abstract
The impacts of climate change on North Atlantic nutrient chemistry remain poorly understood, as there exist a multitude of rapidly-changing biological and physical drivers of nutrient conditions throughout the region. Here, we present nitrogen isotope measurements derived from a six-hundred-year-old crustose coralline alga (δ15Nalgal) to elucidate historic and contemporary trends in Labrador Shelf nitrate utilization, defined as the degree of biological nitrate uptake relative to supply. Prior to ~1800, periods during which utilization approached completion corresponded to neutral modes of the Atlantic Multidecadal Oscillation, which we argue promoted favorable oceanographic conditions for simultaneous phytoplankton growth and reduced nitrate input. More recently, nearly-complete utilization occurred concomitantly with a weakened Labrador Current, suggesting reduced nutrient inflow from eastern subpolar waters. These results highlight the role of ongoing climate-induced circulation changes in driving nutrient distributions throughout the subpolar North Atlantic, which may have implications for future fisheries and oceanic carbon storage.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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 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".