Sediment–water interface

In oceanography and limnology, the sediment–water interface is the boundary between bed sediment and the overlying water column. The term usually refers to a thin layer (approximately 1 cm deep, though variable) of water at the very surface of sediments on the seafloor. In the ocean, estuaries, and lakes, this layer interacts with the water above it through physical flow and chemical reactions mediated by the micro-organisms, animals, and plants living at the bottom of the water body. The topography of this interface is often dynamic, as it is affected by physical processes (e.g. currents causing rippling or resuspension) and biological processes (e.g. bioturbation generating mounds or trenches). Physical, biological, and chemical processes occur at the sediment-water interface as a result of a number of gradients such as chemical potential gradients, pore water gradients, and oxygen gradients.