Figure 6.

Respiration in aerobic and anaerobic environments. Among other potential pathways in the Soudan mine, electrons are transferred from hydrogenases to either cytochromes and then to oxygen to produce water in an oxidative environment, or via nitrate and nitrite reductases (denitrification) in anaerobic environments. Genes encoding the hydrogenases, respiratory complexes, and terminal cytochromes of the aerobic sample were significantly more abundant in the Red (oxidized) sample, while genes encoding the hydrogenases and denitrification genes were more abundant in the Black (reduced) sample. After Vassieva, O. [25]