Photosynthesis, respiration, and stable isotopes of oxygen in a large oligotrophic lake (Lake Erie, USA–Canada)
Bibliographic record
Abstract
Dissolved oxygen (DO) concentration, isotopic composition (18:16O), and respiratory fractionation (αr) were measured in the east basin of Lake Erie to determine the patterns of planktonic photosynthesis (P) and respiration (R) and to assess a dual isotope, steady-state model for P/R ratios. Values of αr varied significantly between months but averaged close to a widely accepted norm for planktonic respiration (0.982). Isotope dynamics in situ predicted that 33%–53% of hypolimnetic oxygen consumption was by the sediments, consistent with previous knowledge. Except during fall turnover, DO was generally above, and 18:16O below, atmospheric equilibrium in the surface mixed layer (SML), suggesting P/R is usually >1 and agreeing with independent estimates by incubation experiments. P/R ratios calculated from the oxygen isotope model were often inconsistent with the DO and 18:16O data, likely because of uncertainties in αr and nonsteady-state conditions in the SML. The autumnal transition to P/R < 1 was captured better in the DO and 18:16O data than in the incubation experiments. Despite problems with the steady-state model, the isotope data were able to reveal spatial and temporal variations in lake metabolism and indicated a strong autochthonous basis for community metabolism in the SML.
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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 | 0.001 |
| 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) | 0.000 | 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 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".