Definition: Sediment is an environmental substance comprised of any particulate matter that can be transported by fluid flow and which eventually is deposited as a layer of solid particles on the bedor bottom of a body of water or other liquid.
Definition: Gravel is an environmental material which is composed of pieces of rock that are at least two millimeters (2mm) in its largest dimension and no more than 75 millimeters.
Definition: The marine benthic biome (benthic meaning 'bottom') encompasses the seafloor and includes such areas as shores, littoral or intertidal areas, marine coral reefs, and the deep seabed.
