density current, any current in eit

density current, any current in either a liquid or a gas that is kept in motion by the force of gravity acting on differences in density. A density difference can exist between two fluids because of a difference in temperature, salinity, or concentration of suspended sediment. Density currents in nature are exemplified by those currents that flow along the bottom of oceans or lakes. Such subaqueous currents occur because some of the water in an ocean or lake is colder or saltier or contains more suspended sediment and, thus, is denser than the surrounding waters. As a consequence, it sinks and flows along the bottom under the effect of gravity. The difference in density, moreover, slows down the mixing of the current with the overlying waters, enabling it to maintain itself for a relatively long distance.