A brine pool is a big area of brine on the ocean basin, and their pools are bodies of water that have salinity 3 to 5 times greater than the surrounding ocean. For deep-sea brine pools, the source of the salt is the dissolution of large salt deposits through salt tectonics. The brine pool is quite often contains high concentrations of methane, furnishing energy to chemosynthetic animals that’re mostly live near the pool, and these creatures are habitually extremophiles. Brine pools can be found around the world, and are well-documented in the Gulf of Mexico.
Moreover, Brine pools are also recognized to exist on the Antarctic Shelf where the source of brine is salt excluded during formation of sea ice. Therefore, deep-sea and Antarctic brine pools can be very toxic to marine animals. Brine pools are sometimes called seafloor "lakes" because the thick brine does not easily mix with overlying seawater. However, the brine density is increase due to high salinity, which produced a distinctive surface and shoreline for the pool. Hence, when submarines dive into brine pools, they float on the brine surface due to the high salinity density.
Though, the motion of a submarine can form waves across the brine-seawater interface that wash over the surrounding "shoreline". Moreover, deep sea brine pools every so often coincide with cold seep activity and methane released by the seep is processed by bacteria, which have a symbiotic connection with seep mussels living at the edge of the pool. This ecosystem is mainly dependent on chemical energy, and unlike almost all other life on Earth, has slight dependence on energy from the Sun. So, finally It requires a submersible to down thrust to actually penetrate one of these pools, thus equipment, such as a submersible, can actually float on its surface.