Methane Ebullition
Following the assumption given by Rothfuss (1994), bubble formation occurs, if the sum of the partial pressures of all gases in the pore water exceeds a threshold value which is the sum of the hydrostatic and the atmospheric pressures plus the pressure required to move the soil particles. The amount of methane removed in the form of bubbles is thus calculated introducing an empirical equation, as suggested by Walter (1996):
where kbu is a rate constant and Cbu1. is the threshold methane concentration above which bubbles are formed.