Inorganic carbon uptake and intracellular assimilation by subarctic Pacific phytoplankton assemblages
Bibliographic record
Abstract
We report the results of inorganic carbon (C) uptake experiments and activity measurements for carbonic anhydrase, ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), and phosphoenolpyruvate carboxylase (PEPC) in offshore and coastal regions of the eastern subarctic Pacific Ocean. HCO3- was the dominant source of inorganic C taken up by phytoplankton at all sampling locations, accounting for ∼60−90% of total C uptake. The uptake of HCO3- occurred primarily through a direct transport system, while indirect HCO3− use, mediated by extracellular carbonic anhydrase (eCA), played a minor role in the C uptake system. Direct HCO3- transport and eCA activity were not related to ambient nutrient or CO2 concentrations or to phytoplankton biomass (chlorophyll a [Chl a]) or primary productivity. There was significant variability in the biomass-normalized activities of Rubisco, PEPC, and total (intracellular and extracellular) carbonic anhydrase. The activities of all of the enzymes measured exhibited significant correlations with both CO2 concentrations and Chl a. PEPC activity averaged 20% of Rubisco activity (range 0.5-110%), and the PEPC : Rubisco ratio was positively correlated with CO2 concentrations and negatively correlated with Chl a. Carbonic anhydrase activity was strongly anticorrelated with CO2 and positively correlated with Chl a. The results provide evidence for the importance of CO2-regulated carbon concentrating mechanisms in marine waters.
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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 | 0.000 |
| 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".