Microbial sulfur cycling determinants and implications for environmental impacts
Bibliographic record
Abstract
Sulfur-oxidizing bacteria (SOB) play a vital role in the occurrence of sulfur oxidation intermediate (SOI) compounds often recalcitrant to currently available, abiotic treatment within metal mine tailings impoundments (TI). As inadvertent SOI discharge post-treatment can lead to the uncontrolled acidification of receiving environments, it becomes increasingly important to elucidate the environmental controls on SOB identities and sulfur cycling within these relatively unstudied systems. Here, results identified controlling factors on SOB community differentiation and associated metabolic pathway occurrence through integrated physicochemical, geochemical, and microbial field and experimental investigation across three summers (2016, 2017, 2021) in a stratified Northern Ontario base metal TI. Dynamic shifts in SOB communities and sulfur oxidation pathways were primarily driven by [S 2 O 3 2− ] and further influenced by pH, [O 2 ], and conductivity. At [S 2 O 3 2− ] above 0.03 mM, Halothiobacillus spp. was observed to dominate in lower pH, higher conductivity conditions where complete SOI oxidation, mediated through the complete Sox pathway, is suggested to reduced [SOI] in treated discharge waters. At [S 2 O 3 2− ] below 0.03 mM, an SOB assemblage ( Thiovirga spp., Thiobacillus spp., and Sediminibacterium spp.) was observed to collectively dominate under higher pH and lower conductivity, associated with SOI persistence due to SOI recycling pathways (incomplete Sox, rDSR, S 4 I). Targeted SOB enrichment cultures confirmed the importance of S 2 O 3 2− availability in driving SOB community shifts and the capability of Halothiobacillus to outcompete other SOB under oxygenated, high [S 2 O 3 2− ] conditions. Trends observed here for mine TI associated SOB were found to also occur across a broader suite of contexts using literature data, indicating their wider ecological relevance in interpreting outcomes associated with SOB activity. Results also provide new insights into improved, biologically informed management of sulfur associated risks with potential SOB manipulation through [S 2 O 3 2− ], pH, and/or [O 2 ] controls. • Sulfur oxidation intermediate compounds (SOI) pose risks to receiving environments. • Extent of microbial S transformations in tailings impoundments driven by [S 2 O 3 2− ]. • [S 2 O 3 2− ] > 0.3 mM favors sole Halothiobacillus domination and decreased S risks. • [S 2 O 3 2− ] < 0.3 mM favors an SOB assemblage and persistent S compounds. • PH, [O 2 ], and conductivity further influence SOB type and thus S risks.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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 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".