The diversity of diatom assemblages in ships' ballast sediments: colonization and propagule pressure on Canadian ports
Bibliographic record
Abstract
This research focused on the specific diversity of diatoms carried in ballast sediments of ships reaching Canadian ports on the Pacific, Atlantic and the Great Lakes during 2007 and 2009. The inventory of 180 taxa included Thalassiosira, Chaetoceros spores, Cyclotella, Actinocyclus, Aulacoseira, Melosira and Pseudo-nitzschia as the most species-rich genera found in 142 samples of the matter settled at the bottom of ship tanks. We also tested and showed evidence that diatom species composition identified in any given tank was the product of: (i) species intrinsic survival strategies, (ii) the most recent ballast water exchange (BWE), and (iii) the cumulative end result of past ballast operations. Multivariate analysis reduced our data set to three assemblages. Propagule pressure of these potentially colonizing assemblages may be enhanced due to repeated introduction attempts by ships belonging to different ballast management categories (transoceanic, intra-coastal with our without BWE) but that actually carried the same assemblage type. A non-linear relationship between colonization and propagule pressure confirms that the early stages of invasion (ballast uptake, survival in the tank) structure the later stages. Coastal floras in tanks that underwent offshore BWE (particularly persisting freshwater species) corroborate concern with the low efficiency of this management option.
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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 | 0.001 | 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) | 0.001 | 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".