Nitrogen fixation and identification of potential diazotrophs in the Canadian Arctic
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Global gaseous nitrogen (N 2 ) fixation rates may be underestimated and data is lacking from many regions without conspicuous diazotrophic cyanobacteria, such as cold oceans. We estimated N 2 fixation rates at diverse sites in the Canadian Arctic, including the mouth of the Mackenzie River, the offshore Beaufort Sea, Lancaster Sound, Baffin Bay and a river influenced fjord. We also identified potential diazotrophic communities using a targeted survey of the nifH gene. Nitrogen fixation rates ranged from 0.02 nmol N L −1 d −1 in Baffin Bay to 4.45 nmol N L −1 d −1 in the Mackenzie River plume. Sequences recovered from the nifH gene survey belonged mainly to Cluster III, a group of nifH sequences associated with diverse microorganisms, with some α ‐ and γ ‐proteobacteria nifH genes at most sites. Cyanobacteria nifH genes with best matches to Nostocales, which are common in Arctic freshwaters, were recovered from the marine Beaufort Sea. The geographic pattern of N 2 fixation rates and nifH gene identities suggest that the Mackenzie River is the source of a diazotrophic community that contributes new nitrogen to the nitrogen‐depleted surface waters of the Beaufort Sea. This first record of N 2 fixation at high latitudes refines our understanding of the global nitrogen budget.
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.
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 | 0.000 |
| 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 it