JOINT EFFECTS OF UV RADIATION AND PHOSPHORUS SUPPLY ON ALGAL GROWTH RATE AND ELEMENTAL COMPOSITION
Bibliographic record
Abstract
Phytoplankton growth and elemental composition are influenced by a number of factors such as photosynthetically active radiation (PAR) and nutrient availability. However, little is known about the influence of solar ultraviolet radiation (UVR) and interactions with nutrients on algal growth processes in situ. We tested the effects of solar radiation and phosphorus supply on algal growth kinetics and elemental composition in two boreal lakes (northwestern Ontario, Canada) during summer 1999. Growth bioassays (at five phosphorus concentrations) assessed changes in algal growth and elemental composition exposed to (1) ultraviolet A [UVA], ultraviolet B [UVB], and photosynthetically active radiation [PAR], (2) UVA and PAR, and (3) PAR only. Growth rates, calculated from changes in seston carbon and chlorophyll, responded strongly to both P and UVR. Results indicated that phytoplankton growth was co-regulated by P limitation and UVR suppression, with highest growth rates found in high P, low UVR treatments. Phytoplankton exposed to both UVA and UVB generally grew more slowly than those exposed to PAR only, even at high P levels. UVB and UVA reduced maximum growth rates by 8–66% and 11–21%, respectively. Phytoplankton growth was more strongly affected by UVB in spring than later in summer, possibly due to shifts in the dominant species present. Manipulations of light and P supply both significantly affected seston C:P ratios. UVR reduced sestonic C:P. Such changes in growth rates and C:P ratios from UVR exposure may have important implications for pelagic food web dynamics.
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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 | 0.000 |
| Scholarly communication | 0.001 | 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 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".