Modeling biogeochemical kinetics: Issues and data needs

This paper focuses on reactive biogeochemical modeling issues and data needs. We show that (1) the minimum number of kinetic data needs is equal to the number of linearly independent kinetic reactions; (2) kinetic reactions that are linearly dependent on only equilibrium reactions are irrelevant; (3) a kinetic reaction that is linearly independent of other kinetic reactions can be analyzed based on one curve of kinetic-variable concentration-vs-time; and (4) kinetic reactions that are linearly dependent on each other can not be uniquely segregated for kinetic analyses. A simple example of biogeochemical reactive systems is used to illustrate the idea of assessing system consistency and minimum data needs for reaction-based modeling. This example considers the bioreduction of ferric oxide. It highlights the need for simple 'model' systems to study biogeochemical reactions because the inclusion of additional species will involve several more reactions and usually always increase the minimum number of species concentrations that must be measured.