Inhibition of growth in two dinoflagellates by rapid changes in external pH
Bibliographic record
Abstract
The effect of external pH and high CO2 were investigated on growth and photosynthesis in two marine dinoflagellates, Amphidinium carterae Hulburt and Heterocapsa oceanica Stein. Exposure of both species to high CO2 caused a rapid decrease in external pH from 8 to 7 and a complete suppression of growth. Both species were able to grow at pH 7 but the Vmax of photosynthesis was significantly lower than in cells grown at pH 8. There was also a significant reduction in the photosynthetic rate of both species after being on high CO2 for 6 h and a complete loss after 24 h. The internal pH of both species was determined by the distribution of [2-14C]5,5-dimethyloxazolidine-2,4-dione between the cells and the surrounding medium. As the external pH was lowered from 8 to 7, there was a decrease in the internal pH of A. carterae cells, grown at pH 8.0, from 7.92 to 7.04 and in H. oceanica from 8.14 to 7.22. When placed on high CO2, the internal pH of A. carterae further declined to 6.90 and to 7.15. in H. oceanica. This inability to maintain internal pH probably caused the suppression of growth and loss of photosynthetic capacity of high-CO2 cells.Key words: Amphidinium carterae, CO2-concentrating mechanism, dinoflagellates, external pH, Heterocapsa oceanica, internal pH.
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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 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 | 0.001 |
| 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".