Effects of UV on photosynthesis of Antarctic phytoplankton: models and their application to coastal and pelagic assemblages
Bibliographic record
Abstract
We have characterized the photosynthetic response to ultraviolet radiation (UV) of natural phytoplankton assemblages in Antarctic (Southern Ocean) waters. Biological weighting functions (BWFs) and exposure response curves for inhibition of photosynthesis by UV were measured during spring-time ozone depletion (October-November). Two different models were developed to relate photosynthesis to UV exposure. A model that is a function of the duration of exposure (BWF H) applied to assemblages in the well-mixed open waters of the Weddell-Scotia Confluence (WSC, 60° S, 50° W), since responses were a function of cumulative exposure and recovery rates were slow. These assemblages had a variable but generally high sensitivity to UV. A steady-state model (BWF E) applied in the shallow waters near the Antarctic Peninsula (Palmer Station, 64° S, 64° W), where inhibition was a function of irradiance (reciprocity failed), and recovery was rapid. Using information on the time-dependence of photosynthesis in assemblages with active repair, inferences were drawn on the relative contribution of damage and recovery processes to the UV weights. BWFs for Palmer phytoplankton sampled during periods of pack-ice cover had both higher damage and higher repair than BWFs for WSC assemblages. BWFs for Palmer phytoplankton sampled during open water periods had about the same damage weights as Weddell-Scotia assemblages but had a higher repair rate. Solar exposures of more than 10 min were predicted to have generally less effect on Palmer phytoplankton than the WSC phytoplankton Se caracterizó la respuesta fotosintética a radiación ultravioleta (RUV) en poblaciones naturales de fitoplancton del Océano Antártico. Se midieron las funciones espectrales de peso biológico (BWFs) y curvas de inhibición de fotosíntesis en respuesta a la exposición de RUV durante la temporada de mayor disminución de la capa de ozono (octubre-noviembre). Se desarrollaron dos modelos distintos que relacionan fotosíntesis con exposición a RUV. Un modelo considera la curva de respuesta al tiempo de exposición (BWF H) debido a que se observo que las respuestas dependían de la exposición acumulativa y que la velocidad de recuperación fotosintéticas era lenta. Este modelo se aplica a poblaciones de fitoplancton residentes en mar abierto y en las aguas turbulentas de la Confluencia Weddell-Scotia (WSC, 60° S, 50° O). Estas poblaciones tienen una sensibilidad a la RUV variable y generalmente alta. El segundo modelo analiza el estado de equilibrio (BWF E) y se aplica a las comunidades residentes en aguas poco profundas cerca de la Península Antártica (Estación Palmer, 64° S, 64° O), donde la inhibición dependió de la irradiación (reciprocidad falló), y donde la recuperación fue rápida. Usando la información derivada de la dependencia al tiempo de fotosíntesis en poblaciones con recuperación rápida, se pudo inferir la contribución relativa de procesos de daño y recuperación al peso espectral de la RUV. El método se aplicó a datos preliminares obtenidos en la Estación Palmer. Las BWFs de poblaciones recolectadas en Palmer cuando la capa de hielo que cubre las aguas es compacta asignaron más peso al daño y a una alta recuperación que las BWFs determinadas para poblaciones de WSC. Las BWFs de muestras de fitoplancton de Palmer durante el periodo de aguas abiertas tienen el mismo peso al daño que en aquellas de poblaciones de WSC aun cuando tienen una velocidad de recuperación más alta. Se predice que la exposición solar por más de 10 min en general tiene menos efecto sobre el fitoplancton de Palmer que sobre el fitoplancton de WSC
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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 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".