DIEL VARIATIONS IN OPTICAL PROPERTIES OF <i>IMANTONIA ROTUNDA</i> (HAPTOPHYCEAE) AND <i>THALASSIOSIRA PSEUDONANA</i> (BACILLARIOPHYCEAE) EXPOSED TO DIFFERENT IRRADIANCE LEVELS<sup>1</sup>
Bibliographic record
Abstract
Diel variations of cellular optical properties were examined for cultures of the haptophyte Imantonia rotunda N. Reynolds and the diatom Thalassiosira pseudonana (Hust.) Hasle et Heimdal grown under a 14:10 light:dark (L:D) cycle and transferred from 100 μmol photons · m(-2) · s(-1) to higher irradiances of 250 and 500 μmol photons · m(-2) · s(-1) . Cell volume and abundance, phytoplankton absorption coefficients, flow-cytometric light scattering and chl fluorescence, and pigment composition were measured every 2 h over a 24 h period. Results showed that cell division was more synchronous for I. rotunda than for T. pseudonana. Several variables exhibited diel variability with an amplitude >100%, notably mean cell volume for the haptophyte and photoprotective carotenoids for both species, while optical properties such as flow-cytometric scattering and chl a-specific phytoplankton absorption generally showed <50% diel variability. Increased irradiance induced changes in pigments (both species) and mean cell volume (for the diatom) and amplified diel variability for most variables. This increase in amplitude is larger for pigments (factor of 2 or more, notably for cellular photoprotective carotenoid content in I. rotunda and for photosynthetic pigments in T. pseudonana) than for optical properties (a factor of 1.5 for chl a-specific absorption, at 440 nm, in I. rotunda and a factor of 2 for the absorption cross-section and the chl a-specific scattering in T. pseudonana). Consequently, diel changes in optical properties and pigmentation associated with the L:D cycle and amplified by concurrent changes in irradiance likely contribute significantly to the variability in optical properties observed in biooptical field studies.
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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) | 0.001 | 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".