Inorganic carbon uptake by Southern Ocean phytoplankton
Bibliographic record
Abstract
We report the results of laboratory and field studies examining inorganic carbon (C i ) utilization by Southern Ocean phytoplankton. Both in monospecific laboratory cultures of diatoms and Phaeocystis antarctica and in natural assemblages in the Ross Sea, C i uptake by phytoplankton was dominated by direct HCO 3 1 transport. The contribution of HCO 3 1 transport to total C i uptake ranged from 65% to 95%, with an overall average of ∼80%. There was no significant difference among diatoms and Phaeocystis in the extent of HCO 3 1 transport. Extracellular carbonic anhydrase activity (eCA) was detected in eight of nine laboratory phytoplankton cultures and in all natural assemblages in the Ross Sea. The effective catalytic enhancement of HCO 3 1 : CO 2 interconversion ranged from 1.5‐ to 13‐fold (overall mean ∼4‐fold). Diatom‐dominated Ross Sea assemblages had significantly greater eCA levels than did Phaeocystis‐dominated assemblages. We found no strong correlations between C i uptake parameters and in situ CO 2 concentrations or chlorophyll a levels in the Ross Sea assemblages. Incubation experiments with natural assemblages showed that HCO 3 1 uptake and eCA expression did not change significantly over an 8‐fold range in pCO 2 (10.1‐81.1 Pa), although total short‐term C fixation rates increased under low CO 2 conditions. Carbon‐concentrating mechanisms are widespread among Southern Ocean phytoplankton and constitutively expressed by natural assemblages in the Ross Sea.
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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".