Brine pool

A brine pool, also called an underwater lake, deepwater lake or brine lake, is a volume of brine collected in a seafloor depression. These pools are dense bodies of water with a salinity typically three to eight times greater than the surrounding ocean, and are commonly found below polar sea ice and in the deep ocean. Pools beneath sea ice form through a process called brine rejection, while deep-sea brine pools draw their salt either from the dissolution of large salt deposits through salt tectonics or from geothermally heated brine issuing from tectonic spreading centers.