Milwaukee Deep Milwaukee Deep Milwaukee Deep, also known as The Milwaukee Depth, () is the deepest part of the Atlantic Ocean and is part of the Puerto Rico Trench. It has a maximum depth of at least . It is just north of the coast of Puerto Rico at "Punto Palmas Altas" in Manatí. This ocean floor feature is named for the USS "Milwaukee" (CL-5), a U.S. Navy Omaha class cruiser, which discovered the Milwaukee Deep on February 14, 1939 with a reading of . On August 19, 1952, the U.S. Fish and Wildlife vessel "Theodore N. Gill" obtained a reading of
Deep ocean water Deep ocean water Deep ocean water (DOW) is the name for cold, salty water found deep below the surface of Earth's oceans. Ocean water differs in temperature and salinity. Warm surface water is generally saltier than the cooler deep or polar waters; in polar regions, the upper layers of ocean water are cold and fresh. Deep ocean water makes up about 90% of the volume of the oceans. Deep ocean water has a very uniform temperature, around 0-3°C, and a salinity of about 3.5% or as oceanographers state as 35 ppt (parts per thousand). In specialized locations such as the