Fig. 2
Maximum quantum yield (Fv/Fm) of M. stellatus and C. crispus: Fv/Fm (% of initial) of thallus branches during exposure to high light (10× Ek; 0 to 120 min) and recovery from the high-light treatment under dim light (approximately 3 µmol photons m−2 s−1; 120 to 240 min) in a October 2011, b March 2012, c May 2012 and d August 2012. Measurements of Fv/Fm were carried out at the beginning of the experiment (0 min), after 15, 30, 60 and 120 min of high-light exposure as well as after 15, 30, 60 and 120 min of recovery. To allow a better comparability between the three algal isolates (Mast-ex, Mast-ov, Chon-ov), Fv/Fm was calculated as percentage of initial values. Data points are means ± 95% confidence intervals (n = 5). Mast-ex, Mastocarpus stellatus from higher levels of the lower intertidal; Mast-ov, Mastocarpus stellatus from overlapping zone in deeper levels of lower intertidal; Chon-ov, Chondrus crispus from overlapping zone in deeper levels of lower intertidal