Sulfate reduction and hydrogen sulfide oxidation rates in marine sediments with cryptic sulfur cycling
Bibliographic record
Abstract
Sedimentary systems affected by high fluxes of reactive iron develop a so-called ‘cryptic’ sulfur cycle in which hydrogen sulfide is nearly fully reoxidized and its concentrations of hydrogen sulfide in the porewaters are in the submicromolar range. The sediments of the Gulf of Aqaba represent a classic example of such a system. The goal of this work was to provide quantitative constraints on hydrogen sulfide concentrations in the sediments of the Gulf of Aqaba. Sulfate reduction rates in the sediments of the Gulf of Aqaba were found to be lower than in marine sediments that had not been affected by high fluxes of the reactive iron, while the rate constants of hydrogen sulfide oxidation were found to be higher than in the highly reactive iron-rich sediments of the Svalbard fjord. A combination of slow rates of sulfate reduction and fast rates of hydrogen sulfide oxidation results in concentrations of hydrogen sulfide in the porewater, both measured and calculated, that are below 100 nmol l −1 . We suggest that a similar cycling of sulfur species may occur in organic-matter-poor marine systems situated in dry environments with highly reactive iron mineral delivery, such as the Red Sea and the Atlantic Ocean in the vicinity of the Sahara.
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 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 | 0.000 | 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".