Table 2.
Photophysiological parameters and tissue stoichiometry in Ulva rigida after seven-day incubation under different pCO2 and irradiance
| Parameter | LL 31 μmol photons m−2 s−1 | SL 274 μmol photons m−2 s−1 | ||
|---|---|---|---|---|
| LC 471 μatm pHT 7.97 | HC 1224 μatm pHT 7.59 | LC 471 μatm pHT 7.97 | HC 1224 μatm pHT 7.59 | |
| Fv/Fm (rel. units) | 0.813 ± 0.011 | 0.821 ± 0.008 | 0.807 ± 0.010 | 0.809 ± 0.023 |
| ETRmax (μmol electrons m−2 s−1) | 28.9 ± 3.0 | 30.6 ± 5.6 | 42.2 ± 1.6 | 42.8 ± 3.5 |
| Ek (μmol photons m−2 s−1) | 165.5 ± 16.9 | 169.6 ± 40.6 | 241.5 ± 9.1 | 245.3 ± 19.8 |
| α (μmol electrons μmol−1 photons) | 0.227 ± 0.008 | 0.227 ± 0.005 | 0.195 ± 0.012 | 0.187 ± 0.014 |
| Chla (μg mg−1 FW) | 1.45 ± 0.27 | 1.68 ± 0.12 | 1.09 ± 0.19 | 0.92 ± 0.21 |
| Chlb (μg mg−1 FW) | 0.88 ± 0.13 | 0.95 ± 0.05 | 0.49 ± 0.05 | 0.42 ± 0.06 |
| Chla/b | 1.64 ± 0.09 | 1.76 ± 0.14 | 2.19 ± 0.22 | 2.20 ± 0.30 |
| C:N | 9.7 ± 0.5 | 9.6 ± 0.3 | 10.5 ± 0.7 | 10.0 ± 0.8 |
Maximum quantum yield of PSII (Fv/Fm), electron transport rate-irradiance (ETR-E) curve parameters, that is, ETRmax, Ek, and α estimated using the hyperbolic tangent model of Jassby and Platt (1976), pigments, and molar C:N of U. rigida under different light (LL and SL; limiting and saturating light, respectively) and pCO2 concentrations (LC and HC; low and high pCO2, respectively). Data are means ± standard deviations (n = 6). FW – fresh weight.