Spatial variation in carbon source use and trophic position of ringed seals across a latitudinal gradient of sea ice
Bibliographic record
Abstract
Anthropogenic climate change is causing changes to the Arctic sea-ice system with implications for the magnitude and timing of Arctic pelagic and ice-associated (sympagic) primary production that influences food web interactions. Ringed seals (Pusa hispida) are generalist predators that, as a species experience vastly different icescapes from low to high-Arctic latitudes. Quantifying spatial variation in their diet can help us understand how changes in sea-ice dynamics affect trophic interactions in Arctic marine food webs. However, multiple complementary analytical tools to examine variation in carbon source use and trophic dynamics in the diet of ringed seals have not yet been applied across their latitudinal range in the Arctic. We conducted stable isotope analysis (δ13C and δ15N) and measured highly branched isoprenoid diatom lipid biomarkers of ringed seals from the low, intermediate, and high Arctic (from 61.1°N to 77.5°N) to investigate spatial variation in their carbon source use and trophic position in relation to sea-ice dynamics. Both δ13C and highly branched isoprenoids indicated that ringed seals from higher latitudes had more sympagic carbon in their diet (liver δ13C: −18.3 ± 0.2 ‰, HBI: 89.9 ± 2.08 %) than ringed seals at lower latitudes (liver δ13C: −21.1 ± 0.1 ‰, HBI: 22.0 ± 2.73 %). Ringed seal trophic position increased from the low (3.78 ± 0.02) to high (4.76 ± 0.03) Arctic, suggesting increased fish consumption or a different trophic structure coinciding with the latitudinal change in carbon source. Ringed seals demonstrated a clear shift from low to high Arctic in the relative contribution of phytoplanktonic vs sympagic primary production. These patterns are likely linked to the vastly different icescapes in these environments and demonstrate that shifts in primary producer composition and Arctic food webs can be identified in ringed seal diets. Information on these prey and energy shifts over large spatial scales also provides insights into potential future changes to Arctic ecosystem function with continued sea-ice decline.
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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 | 0.000 | 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 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".