Temporal, spatial, and interspecific variation in geochemical signatures within fish otoliths, bivalve larval shells, and crustacean larvae
Bibliographic record
Abstract
Geochemical signatures of early life stages are increasingly used to study population connectivity. This approach utilizes spatial variability in chemical signatures to predict natal or nursery origins of post-dispersal individuals by comparison with a chemical reference atlas created from individuals of known origin. To examine the relative importance of spatial, temporal, and species variation in elemental signatures, we synthesized the chemical information of otoliths, larval shells, and whole larvae from studies that employed natural geochemical signatures in San Diego County, USA between 1997 and 2009. We compared 8 elements analyzed from 4 bivalve species, 2 larval or juvenile fishes, and Stage 1 crab zoeae. Across all species, different sets of elements best discriminated among open-coast sites or within or among bays and lagoons. In mytilid mussels, which had the most complete record, all 8 elements were more variable over time than space at the site level, highlighting the need to resample the reference atlas during each study. More coarsely, however, bay and lagoon taxa maintained distinct chemical signatures both from each other and from those on the open coast, despite interannual variability. Spatially identifiable signatures for all species were likely imparted by a combination of pollution in bays and export to adjacent coastlines (copper, lead), a heterogeneous distribution of land-sourced elements (manganese, cobalt, uranium), and incorporation that may vary in response to temperature (barium, manganese, strontium) and salinity (7 elements). These results identify important elements for larval tracking of additional species depending on habitat and life history; however, source population signatures appear species-specific.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".