Sailing into the past: Nautical charts reveal changes over 160 years in the largest reef complex in the South Atlantic Ocean
Bibliographic record
Abstract
Coral reefs are in global decline due to unprecedented anthropogenic threats that have escalated and accumulated over decades to centuries. In order to assess the magnitude and drivers of changes on reefs, it is necessary to reconstruct the history of changes of these ecosystems over this longer time scale. We compiled and assessed historical records of naturalists that visited Abrolhos reefs over the last 202 years, and compared a 160-year-old nautical chart with modern charts to quantify losses in the spatial extent of coastal reefs in the Abrolhos Bank, Brazil. We found a 28% loss in the overall spatial extent of inshore reefs, with some areas experiencing declines up to 49% over the past 160 years. Such reefs with more dramatic changes (Guaratibas reefs) are the closest to the coast (∼7 km), where local impacts such as the past extraction of coral for lime since the 19th century, as well as increased coastal sedimentation and siltation due to deforestation are concentrated and that, combined, may have caused the observed decline. Collectively, this set of historical information captures coral reef changes over time, and helps update conservation and restoration goals for the Abrolhos reefs seascape.
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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 | 0.001 | 0.005 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.005 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".