Parameters of the mass transfer equation for the upstream and downstream locations of Vallisneria spiralis and Vallisneria americana (flat and twisted configurations) determined from O2 profiles and through theoretical formulations using measurements of the velocity gradient by digital particle image velocimetry
| Measurement technique . | [CO2] (mmol m–3) . | Species . | N . | Location . | Slope . | Intercept . | r2 . | P . | . |
|---|---|---|---|---|---|---|---|---|---|
| (A) Microsensor | 17.1 | V. spiralis | 6 | US | 0.50±0.13 | 0.06±0.30 | 0.72 | *** | a |
| 17.1 | V. spiralis | 6 | DS | 0.87±0.09 | –0.66±0.30 | 0.94 | *** | b | |
| 17.1 | V. americana | 6 | US | 0.52±0.11 | 0.11±0.26 | 0.78 | *** | a | |
| 17.1 | V. americana | 6 | DS | 0.70±0.10 | –0.18±0.32 | 0.89 | *** | c | |
| 17.1 | V. americana (twisted) | 8 | DS | 0.82±0.07 | –0.43±0.22 | 0.96 | *** | b | |
| 1.71 | V. spiralis | 9 | US | 0.50±0.06 | 0.10±0.14 | 0.92 | *** | a | |
| 1.71 | V. spiralis | 9 | DS | 0.69±0.05 | –0.13±0.14 | 0.97 | *** | c | |
| 1.71 | V. americana | 6 | US | 0.47±0.14 | 0.25±0.33 | 0.68 | * | a | |
| 1.71 | V. americana | 6 | DS | 0.95±0.09 | –0.83±0.29 | 0.95 | *** | – | |
| (B) PIV | NA | V. spiralis | NA | US | 0.68±0.08 | –0.56±0.19 | 0.92 | *** | – |
| NA | V. spiralis | NA | DS | 0.70±0.06 | –0.06±0.20 | 0.95 | *** | e | |
| NA | V. americana | NA | US | 0.80±0.12 | –0.83±0.28 | 0.88 | *** | d | |
| NA | V. americana | NA | DS | 0.80±0.06 | –0.34±0.19 | 0.97 | *** | – | |
| NA | V. americana (twisted) | NA | US | 0.77±0.06 | –0.63±0.14 | 0.96 | *** | d | |
| NA | V. americana (twisted) | NA | DS | 0.66±0.08 | 0.05±0.25 | 0.94 | *** | e |
| Measurement technique . | [CO2] (mmol m–3) . | Species . | N . | Location . | Slope . | Intercept . | r2 . | P . | . |
|---|---|---|---|---|---|---|---|---|---|
| (A) Microsensor | 17.1 | V. spiralis | 6 | US | 0.50±0.13 | 0.06±0.30 | 0.72 | *** | a |
| 17.1 | V. spiralis | 6 | DS | 0.87±0.09 | –0.66±0.30 | 0.94 | *** | b | |
| 17.1 | V. americana | 6 | US | 0.52±0.11 | 0.11±0.26 | 0.78 | *** | a | |
| 17.1 | V. americana | 6 | DS | 0.70±0.10 | –0.18±0.32 | 0.89 | *** | c | |
| 17.1 | V. americana (twisted) | 8 | DS | 0.82±0.07 | –0.43±0.22 | 0.96 | *** | b | |
| 1.71 | V. spiralis | 9 | US | 0.50±0.06 | 0.10±0.14 | 0.92 | *** | a | |
| 1.71 | V. spiralis | 9 | DS | 0.69±0.05 | –0.13±0.14 | 0.97 | *** | c | |
| 1.71 | V. americana | 6 | US | 0.47±0.14 | 0.25±0.33 | 0.68 | * | a | |
| 1.71 | V. americana | 6 | DS | 0.95±0.09 | –0.83±0.29 | 0.95 | *** | – | |
| (B) PIV | NA | V. spiralis | NA | US | 0.68±0.08 | –0.56±0.19 | 0.92 | *** | – |
| NA | V. spiralis | NA | DS | 0.70±0.06 | –0.06±0.20 | 0.95 | *** | e | |
| NA | V. americana | NA | US | 0.80±0.12 | –0.83±0.28 | 0.88 | *** | d | |
| NA | V. americana | NA | DS | 0.80±0.06 | –0.34±0.19 | 0.97 | *** | – | |
| NA | V. americana (twisted) | NA | US | 0.77±0.06 | –0.63±0.14 | 0.96 | *** | d | |
| NA | V. americana (twisted) | NA | DS | 0.66±0.08 | 0.05±0.25 | 0.94 | *** | e |
Mass transfer equation: Shx=ARexBScC(C=0.33), where A is slope and B is 10intercept, for upstream (US)and downstream (DS) locations. PIV, digital particle image velocimetry; NA:not applicable
Values for slope and intercept are means ± s.e.m.
P<0.05
P<0.001. Lowercase letters indicate slopes that are similar statistically