Sediment–Water Interfaces, Chemical Flux at

Numerous individual transport processes which mobilize chemicals on either side of the interface have been studied. However, a consistent theoretical framework connecting the processes across the interface that correctly quantifies the overall flux remains elusive. This occurs because two fundamentally different individual flux relationships are needed to represent the two very different transport mechanisms needed for quantifying the numerous chemical, biological, and physical processes ongoing at this unique locale. The two basic types of transport processes are the chemical potential driven and the media advection driven. Several theoretical modeling approaches exist for combining these, but all have problematic conceptual features, which will be reviewed. By generalizing flux continuity across the interface, which is the fundamental basis for arriving at the well-known and accepted two-resistance theory, the “interface compartment model” is presented and offered as a unifying theory describing advection-driven and potential-driven transport across the sediment–water interface.