A. Photosynthesis (gross primary production) (Equation 11.1) B. Plant respiration (Equation 11.2) C. Root exudation of dissolved organic carbon (DOC) D. Death, senescence of leaves β particulate organic carbon (POC) and DOC to aerobic zone E. Aerobic soil respiration F. Transfer of POC, DOC from aerobic zone to anaerobic zone G. Anaerobic respiration (denitrifi cation, fermentation) of POC H. Anaerobic respiration (denitrifi cation, iron reduction, fermentation, sulfate reduction, methanogenesis) of DOC (e.g. Equation 11.3) I. Methanogenesis via CO 2 reduction (Equation 11.4) J. Methane release to surface. J 1 = diffusion; J 2 = ebullition; J 3 = plant transport K. CO 2 release to surface. K 1 = diffusion; K 2 = ebullition; K 3 = plant transport L. Methane oxidation (Equation 11.5) M. Dissolved inorganic carbon (DIC) leaching (M 1 ) and input (M 2 ) (e.g. via groundwater fl ow or fl ooding) N. Dissolved organic carbon (DOC) leaching (N 1 ) and input (N 2 ) O. Particulate organic carbon (POC) leaching (O 1 ) and input (O 2 )