Room temperature chlorophyll fluorescence
The activities of PSI and PSII were measured in dark-adapted exponentially growing cultures with a Dual-PAM-100 system (Heinz Walz GmbH, Effeltrich, Germany) as described in Szyska et al. (2007). All samples were supplemented with 10 mM sodium biocarbonate and measurements were performed in a water-jacketed cuvette at the corresponding growth temperatures. The fluorescence parameters FV/FM(maximum photochemical efficiency), qL (photochemical quenching or proportion of open PSII reaction centers), Φ (PSII) (quantum yield of photochemistry), and Φ (NPQ) (nonphotochemical energy dissipation from antenna quenching), and Φ (NO) (energy dissipation from non-regulated processes) were calculated during steady state photosynthesis at the growth temperature/irradiance/salinity regimes. Energy partition parameters of PSI were: quantum yield of PSI (ΦPSI), acceptor side limitation (ΦNA), and donor side limitation (ΦND) (Schreiber & Klughammer, 2008).