Photoreactions of Mercury in Surface Ocean Water: Gross Reaction Kinetics and Possible Pathways
Bibliographic record
Abstract
We present pseudofirst order rate constants for gross photoreduction and gross photooxidation of mercury in surface water from the open Atlantic Ocean, determined under controlled laboratory conditions. Experiments using both unfiltered and filtered ocean water were carried out to characterize the importance of microbes and colloids on reaction kinetics. Results indicate that reduction and oxidation of mercury in ocean water does not follow a simple two-species reversible reaction pathway. We suggest two possible redox pathways that reproduce the pattern of dissolved gaseous mercury (DGM) concentrations observed in our laboratory experiments, and evaluate them using a controlled outdoor experiment. In both proposed pathways Hg(0), the major constituent of DGM, is converted to an unidentified oxidized species that is different from the reducible form present initially. This reaction step plays a major role in the net formation of DGM in our experiments. Our results represent new quantitative information about the gross reaction kinetics for both reduction and oxidation of mercury in open ocean surface water. Pseudofirst order rate constants for reduction reactions that form DGM were determined to be in the range of 0.15-0.93 h(-1) and pseudofirst order rate constants for oxidation of Hg(0) to be in the range of 0.4-1.9 h(-1). Microbes and colloids did not appreciably influence the reduction and oxidation kinetics.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".