Persistence of enteric bacteria in alluvial streams
Bibliographic record
Abstract
A tracer-bacteria was used to study the persistence of enteric bacteria in three alluvial streams (Carroll Creek, Lutteral Creek, Eramosa River) located in Southern Ontario, Canada. Within each stream, a 1.1 m 2 section of the bed was seeded with a strain of Escherichia coli resistant to nalidixic acid (E. coli NAR). The survival of the tracer-bacteria within the stream bed and the release of the tracer-bacteria to the water column were monitored for approximately 3 weeks. Survival dynamics were also studied in each stream using dialysis tubes. In Carroll Creek, where water temperatures were typically lower than 16 °C, the inactivation of the tracer-bacteria did not follow a first order decay. The number of tracer-bacteria within the stream bed did not decrease for the first 5 d of the experiment. Inactivation of the tracer-bacteria within bed sediments of Lutteral Creek and the Eramosa River resembled typical first order decay, preceded by a 24-h lag phase. Water temperatures in Lutteral Creek and the Eramosa River were generally 10 °C higher than in Carroll Creek. Downstream water quality monitoring indicated that the tracer-bacteria was being released from the seeded bed sediments during both baseflow and stormflow periods in Carroll and Lutteral Creeks. However, in the Eramosa River, where bed sediments possessed an organic matter content of 9.5%, the tracer-bacteria was rarely recovered in downstream water samples. Survival dynamics observed in dialysis tubes resembled those observed in bed seeding experiments. The experimental approach employed in this study could be used to further investigate the survival and transport characteristics of sediment-associated bacteria. Key words: E. coli, sediments, survival, streams, tracer-bacteria.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 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".