Figure 2.

Diurnal variation of cyanobacterial N₂-fixation rates (mean±s.e.) for P. schreberi and H. splendens sampled from Ruttjeheden in June and September, and of light and temperature at the incubation site. Data are obtained after consecutive acetylene reduction assay measurements performed after 4 h incubations. In each panel, different letters above data points indicate statistically significant differences between N₂-fixation rates measured at different times of the day for each moss species at each sampling date (ANOVA followed by Tukey's HSD test, α<0.05). ANOVA results are presented in Supplementary Table 2.