Abiotic N2 reduction in submarine hydrothermal systems could quickly fertilize prebiotic oceans
Bibliographic record
Abstract
Abstract NH 3 or NH 4 + is an essential component of the abiotic synthesis of organic compounds for the origin of life and an efficient greenhouse gas to address the faint young Sun paradox on the early Earth. Sustainable NH 3 or NH 4 + on the N 2 -dominated prebiotic Earth’s surface requires potent abiotic N 2 reduction (ANR) in hydrothermal systems, which has not been detected in the geological record despite numerous laboratory demonstrations. Here we report high concentrations and extreme 15 N depletions of NH 4 + in hydrothermal veins in oceanic crusts drilled from the South China Sea basin. Our data indicate that abundant 15 N-depleted NH 4 + was produced by ANR in deep fluid but progressively overprinted by 15 N-enriched biogenic NH 4 + toward the surface. Modeling suggests that ANR could supply up to 9.0 – 10.8×10 10 mol⋅year -1 NH 4 + to global oceans, which is minor to the large nitrogen inventory in modern oceans, but could quickly fertilize the oceans and supply NH 3 to the atmosphere in the prebiotic Earth.
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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 | 0.000 |
| 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 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".