Observations of the sediment-water interface: Marine and fresh water environments

The sediment at the interface immediately beneath the water column is distinct from deeper-lying sediments in its properties and, at least quantitatively, in the processes driving diagenesis. Progress in understanding thesediment-water interface can be based on consideration of fundamentals of biogeochemical particle/fluid interactions and on application of certain biological techniques especially suited to this challenging portion of the sediment column. This article reports results achieved by combining theoretical fundamentals and specialized experimental techniques in the study of the interface from selected depositional environments. For fine-grained and sandy deposits from fresh-water to coastal marine environments, the interface is characterized by exaggerated microrelief, great porosity, and significant biological alteration. Additional application of this research approach is poised to further our understanding of engineering, and acoustic and xenochemical responses of sedimentary materials, with special emphasis on the influence of the bio-organic phase of the interface upon its fabric and physical properties.