Biogeochemical Importance of the Bacterial Community in Uranium Waste Deposited at Key Lake, Northern Saskatchewan
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
The long-term stability of immobilized elements of concern in uranium tailings deposited in the Deilmann Tailings Management Facility (DTMF), northern Saskatchewan, is dependent upon maintenance of highly oxic conditions within the tailings mass. The main objective of this study was to investigate the effect of stimulating microbial activity on the redox potential and state of ferrihydrite, which are considered to be the primary controlling condition and mineral phase, respectively, within the tailings. To determine the potential for biologically mediated decreases in redox potential and ferrihydrite reduction, a series of microcosm assays were performed. Non-sterile material from the tailings–water interface of the DTMF site was inoculated with indigenous flora previously isolated from the tailings material and enriched with a carbon source (50 ppm trypticase soy broth) and incubated under continuous-flow or intermittent-flow conditions, and compared with an uninoculated, no-carbon control that received continuous flow. Highly reducing conditions with redox potentials of less than −300 mV were detected after 2 days of incubation within the carbon-enriched tailings of microcosms receiving continuous flow, and less than −280 mV after 11 days of incubation within carbon-enriched tailings in microcosms receiving intermittent flow. The lowest recorded Eh value (−545 mV) was recorded after 14 days in a carbon-enriched microcosm receiving intermittent flow. In contrast, the redox conditions in the control microcosm never dropped below −93 mV; thus, it was clear that microbial activity and available carbon drove the Eh conditions to become highly reducing. The occurrence of low redox conditions was concomitant with the bulk chemical detection of Fe (II) in the effluent of treated microcosms. Sites of microbial ferrihydrite reduction were also detected using scanning transmission X-ray microscopy where Fe (II) species were observed in close proximity with bacterial cells. Analysis of the microbial diversity present within the microcosms confirmed that microbes indigenous to the DTMF system have the potential to generate conditions suitable for the proliferation of sulfate and iron reducing bacteria, such as Desulfosporosinus, which was detected by high-throughput 16S rRNA gene sequencing.
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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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 it