Influence of temperature on selenium mobility under contrasting redox conditions: a sediment flow-through reactor experiment
Bibliographic record
Abstract
Selenium is an essential micronutrient, whose mobility in cold region underpins both crop quality and the aquatic food web. Our objective is to test for the influence of temperature (4 and 23°C) on Se sequestration in undisturbed sediments using flow-through reactors (FTR) containing fresh or aged organic matter (OM), under environmental relevant low Se conditions. Se speciation along with concentration of ancillary parameters (pH, DOC, NO3-, NO2-, Fe(II), SO42-, HS-) were measured in the outflow during 8 experimental phases in which Se concentrations were sequentially increased. FTR sequestered most of the Se, with fresh OM removing 50% more than aged OM. Temperature response was lower for selenite than for selenate. At 100 nM inflow selenite, in the presence of fresh OM, Se effluxes, comprising of undefined organic Se, were of 0.94 nM d-1 at 23°C and of 0.85 nM d-1 at 4°C. In contrast, at 100 nM inflow selenate, effluxes were of 0.9 nM d-1 at 23°C and an order of magnitude higher at 8.4 nM d-1 at 4°C. Outflow Se was composed of selenite and organic Se species at 23°C and of selenate at 4°C. We hypothesize that selenate reduction was controlled by microbial processes, influenced by temperature, while selenite transformation proceeded via abiotic reactions.
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| 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".