Neoichnology and sediment distribution in tidal flats of the mud‐dominated mesotidal Mira River estuary (Portugal)
Bibliographic record
Abstract
ABSTRACT Invertebrate burrow morphologies and distributions are presented for the tidal flats of the middle and lower reaches of the tide‐influenced (mesotidal), mud‐dominated Mira River estuary (SW Portugal) as an analogue for interpreting the ichnology of palaeoestuarine successions. Burrow distributions are revealed using field observations of biogenic and physical sedimentary structures, trace makers, collected grab samples, push cores and lab measurements of grain size, organic matter and calcium carbonate content and linked to physico‐chemical stresses. Estuarine tidal‐flat surface open burrow distribution and bioturbation intensity are analysed in plan view using free scientific image analysis software (ImageJ) to obtain burrow density, total burrow area and minimum and maximum burrow diameters. The total tidal flat area occupied by organisms ranges from 0.8% to 4.1% in the middle estuary and is 1.4% in the lower estuary. These equate to a bioturbation index of one to two (BI 1–2). However, computed tomography (CT) of push cores (cross‐sectional view) taken on the same tidal flats shows sparse to complete bioturbation intensity (BI 1–6), revealing that tidal flat sediments tend to be more biogenically reworked cumulatively over time with overprinting of subsequent tiers and/or recolonized. CT scanning also allows the identification of more burrow types, demonstrates infaunal tiering and provides insights into trace‐fossil preservation potential. This research shows that the trace communities are heterogeneous and change spatially and temporally along the Mira River estuary, reflecting a physico‐chemical gradient and seasonality. This trend signals changes in sediment composition, substrate type and consistency (sediment compaction and subaerial exposure), salinity, oxygenation, temperature, pH and interplay of tidal versus hydraulic energy.
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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 | 0.000 |
| 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 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".