Fig. 3From: Monitoring of seven industrial anaerobic digesters supplied with biocharQuantification of methanogenic archaea before and after supplementation: The cofactor F420 was used to count methanogenic archaea using epifluorescent microscopy. The QQ plot resulting from the Shapiro–Wilk test (A) is shown as an example for the counting of all archaea (B), but it was also carried out for the counting of Methanosarcina-like clusters (C) and rod-shaped and thread-like archaea (D). Analysis was performed before biochar was added, and 9 and 11 months after supplementation. Each bar shows a mean value of 48 pictures taken from three different slides. A two-tailed paired t-test was applied to assess significanceBack to article page