The interaction of CO2 concentration and spatial location on O2 flux and mass transport in the freshwater macrophytes <i>Vallisneria spiralis</i> and <i>V. americana</i>
Bibliographic record
Abstract
The biology of aquatic organisms determines the maximum rates of physiological processes, but the mass transport of nutrients determines the nominal rates at which these processes occur. Maximum O(2) flux (P(max)) at 17.1 mmol m(-3) CO(2) was higher for the leaves of the freshwater macrophyte Vallisneria spiralis [P(max)=0.013+/-0.001 mmol m(-2) s(-1) (g(chla+b) m(-2))(-1) (mean +/- s.e.m.)] than for the closely related species, Vallisneria americana [P(max)=0.008+/-0.001 mmol m(-2) s(-1) (g(chla+b) m(-2))(-1)]. The O(2) flux saturated at freestream velocities >4.5+/-1.2 cm s(-1) and was spatially invariant for both species. However, a tenfold decrease in CO concentration to 1.71 mmol m(-3) changed the nature of the relationship between O(2) flux and spatial location along the leaf surface, and reduced the O(2) flux of V. spiralis to values similar to V. americana. The O(2) flux [P(max)=0.007+/-0.001 mmol m(-2) s(-1) (g(chla+b) m(-2))(-1)] saturated at the upstream location (i.e. 1 cm from the leading edge of the leaf) but was found to increase linearly with freestream velocity [slope=0.057+/-0.011 mmol m(-2) s(-1) (g(chla+b) m(-2))(-1) (m s(-1))(-1)] at the downstream location (i.e. 7 cm from the leading edge) at freestream velocities >1.8+/-0.9 cm s(-1). Conversely, mass transfer rates did not vary with CO(2) concentration, and were characteristic of a laminar concentration boundary layer at the upstream location and a turbulent concentration boundary layer at the downstream location. Rates of mass transfer measured directly from O(2) profiles were not predicted by theoretical values based on hydrodynamic measurements. Moreover, the concentration boundary layer thickness (delta(CBL)) values measured directly from O(2) profiles were 48+/-2% and 21+/-1% of the predicted theoretical delta(CBL) values at the upstream and downstream locations, respectively. It is evident that physiological processes involving mass transport are coupled and vary in space. Mass transport investigations of biological systems based solely on hydrodynamic measurements need to be interpreted with caution.
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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 | 0.000 | 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".