Primary productivity and the coupling of photosynthetic electron transport and carbon fixation in the Arctic Ocean
Bibliographic record
Abstract
Abstract We examined the light absorption properties and light‐dependent rates of photosynthetic electron transport (ETRRCII) and 14C‐uptake in phytoplankton of the Canadian Subarctic and Arctic Ocean. Our results reveal high variability in the light‐saturated, chlorophyll a‐specific rate of 14C‐uptake (PChlamax; 0.7 to 8.0 mg C mg chl a−1 h−1) , and the light‐dependant efficiency of 14C‐uptake (αChla; 0.01 to 0.09 mg C mg Chl a−1 h−1 [μmol quanta m−2 s−1]−1). Variability in PChlamax correlated with light availability in the stratified water‐column, while both PChlamax and αChla were correlated to the degree of nitrate depletion in the mixed layer. For all samples, we observed that 14C‐uptake rates reached light saturation at lower irradiances than ETRRCII, leading to significant, light‐dependent de‐coupling of carbon fixation and photosynthetic electron transport. For samples taken from within the mixed layer, we found that the conversion factor from ETRRCII to carbon fixation was strongly correlated to the magnitude of non‐photochemical quenching, as derived from fast repetition rate fluorometry (FRRF) measurements. This correlation supports recent findings from the Subarctic Pacific Ocean, and has the potential to improve FRRF‐based estimates of phytoplankton carbon fixation. Our observations reveal distinct environmental regulation of phytoplankton light absorption, electron transport and carbon fixation in phytoplankton assemblages within and below the shallow summer mixed layer, and will help to inform more robust predictions of future primary production in a rapidly changing Arctic Ocean.
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 machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 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 source (direct Gemma or distilled Codex), 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".