## 2.25.7. Reactive Transport Solution[¶](#reactive-transport-solution "Permalink to this headline")
-------------------------------------------------------------------------------------------------

The solution to equation [(2.25.11)](#equation-24-11) is solved in several sequential steps: resolve competition for CH4 and O2 (section [2.25.7.1](#competition-for-ch4and-o2)); add the ebullition flux into the layer directly above the water table or into the atmosphere; calculate the overall CH4 or O2 source term based on production, aerenchyma transport, ebullition, and oxidation; establish boundary conditions, including surface conductance to account for snow, ponding, and turbulent conductances and bottom flux condition (section [2.25.7.2](#ch4-and-o2-source-terms)); calculate diffusivity (section [2.25.7.3](#aqueous-and-gaseous-diffusion)); and solve the resulting mass balance using a tridiagonal solver (section [2.25.7.5](#crank-nicholson-solution-methane)).

