Quantitative Mass Transfer in Coastal Sediments During Early Diagenesis: Effects of Biological Transport, Mineralogy, and Fabric

The long-term goal of this project is to develop multicomponent reactive transport models that can be used to accurately describe solute transport in temporally and spatially heterogeneous, organic-rich sediments. To achieve this goal, we have developed a model that can be used to obtain unbiased 1D quantitative descriptions of biologically-enhanced solute transport (bioirrigation due to macrofaunal activities) from chemical data. We have also developed a quantitative 1D description of bioirrigation that relies on ecological data (i.e., information regarding burrow networks) and requires minimal chemical data. A long-term goal of the project is to use these models to assess the spatial and temporal variability of biologically-enhanced solute transport in a wide range of sedimentary environments and to incorporate these models into existing 1D coupled reactive-transport models. The results of this work will also be used to develop flexible 3D models of enhanced solute transport. These flexible 3D models will be useful for investigation of many spatially and temporally invariant processes, including not only bioirrigation, but also, for example, the effects of macrophytes on solute transport in nearshore sediments.