Multi‐wavelength Pulse Amplitude Modulated fluorometry (Phyto‐<scp>PAM</scp>) reveals differential effects of ultraviolet radiation on the photosynthetic physiology of phytoplankton pigment groups
Bibliographic record
Abstract
Summary The effects of UV‐B, UV‐A and PAR on the photochemistry of phytoplankton from Hamilton Harbour, Lake Ontario, were measured to assess how well a multi‐wavelength Pulse Amplitude Modulated fluorometer (Phyto‐PAM) could discriminate among different pigment groups and to test whether bloom‐forming cyanobacteria in this embayment have comparatively high resistance to sunlight stress. Estimates of abundance for the three groups (blues, greens and browns) identified by the Phyto‐PAM generally agreed with microscope counts, but the maximum quantum efficiency of photochemistry ( F v : F m ) was usually quantified only for the dominant group. In acute exposure experiments, the average inhibition of F v : F m by PAR, UV‐A and UV‐B was <10, 30 and 60% respectively. More inhibition was observed in the cyanobacteria compared to the eukaryotic phytoplankton, due to higher rates of photosystem damage rather than lower rates of recovery based on the Kok model for photoinhibition. Both F v : F m and photosynthetic carbon incorporation showed similar patterns of inhibition. Based on F v : F m our results showed no evidence that cyanobacteria are more resistant to UVR stress compared to other groups, however, their success as bloom‐forming species suggests they must have other mechanisms to tolerate if not thrive under high irradiance conditions. These results demonstrate both the utility and limitations of the Phyto‐PAM for the assessment of group‐specific abundance and physiological responses in a natural community: general seasonal and inter‐group variation can be captured, but improved resolution of less abundant groups would enhance its application.
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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) | 0.001 | 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".