Responses to iron limitation in two colonies of <i>Stylophora pistillata</i> exposed to high temperature: Implications for coral bleaching
Bibliographic record
Abstract
Exposing the coral Stylophora pistillata to seawater depleted in available iron by complexation with the strong chelator desferrioxamine B reduces the photosynthetic efficiency and alters the pigment composition in its symbiotic algae at high temperatures. Similar effects of iron limitation are known for free‐living algae, but this is the first demonstration of low‐iron stress in a dinoflagellate living endosymbiotically. Maintaining corals at elevated temperature (30°C and 31°C) under diminished iron availability leads to reduced maximum quantum yields (Fv:Fm) of photosystem II (PSII), specifically on brightly illuminated surfaces of the coral. This reduction in maximum quantum yield is due in part to increased photoprotection, indicated by an increase in the photoprotective xanthophyll diatoxanthin, which promotes nonphotochemical quenching of excess light energy to restrict oxidative damage under conditions that impair photosynthetic electron transfer. However, photophysiological changes associated with the lowered maximum quantum yield did not prevent photodamage to PSII under the combined effects of elevated temperature and low iron availability, as shown by the decrease in maximum (Fm) that was not accompanied by significant change in the minimum (Fo) fluorescence yield. All of the foregoing is consistent with the potential of iron limitation to contribute to the underlying conditions by which thermal stress evokes the physiological response by corals that culminates in the symbiotic dysfunction of natural bleaching.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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 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".