Photosynthetic oxygen development and respiratory oxygen consumption in μmol O2 h−1 mg−1 Chl. a measured at 200 μmol photons m−2 s−1 as function of increasing temperatures in the four studied strains of Klebsormidium (n = 3, mean value ± SD), BIOTA 14614.7 (African Strain A), BIOTA 14,613.5e (African Strain B), BIOTA 14,614.18.24 (African Strain C) and SAG 384-1 (Arctic Strain). Significances among the treatments were calculated by one-way ANOVA (p < 0.001). Different capital (net photosynthesis) and small letters (respiration) represent significant differences among the temperatures as revealed by Tukey’s post hoc test.