Milwaukee Deep

Milwaukee Deep, also known as the Milwaukee Depth, is the deepest part of the Puerto Rico Trench, constituting the deepest points in the Atlantic Ocean. Together with the surrounding seabed area, known as Brownson Deep, the Milwaukee Deep forms an elongated depression that constitutes the floor of the trench. As there is no geomorphological distinction between the two, it has been proposed that the use of both names to refer to distinct areas should be reviewed.

During the Five Deeps Expedition, explorer Victor Vescovo achieved the first crewed descent to the location on 21 December 2018. Media outlets overwhelmingly referred to the area as the Brownson Deep, while the name Milwaukee Deep was used by others. However, likely due to the factors mentioned above, the expedition has not used any particular name to refer to the site of their Atlantic dive. It is named for the USS Milwaukee, which recorded the first echo soundings of the Puerto Rico Trench in 1939, and was itself named for the city of Milwaukee.

File:Caribbean-map.png

Location of the Puerto Rico Trench, USGS

Located roughly Template:Convert north of the coast of the main island of Puerto Rico at Punto Palmas Altas in Manatí, the maximum depth of the Milwaukee Deep is Template:Convert, as directly measured by Vescovo during his 2018 descent to the deepest point of the Atlantic Ocean. The maximum depth of the Milwaukee Deep has also been reported at Template:Convert in 1940 by geologist and oceanographer Thomas Wayland Vaughan, Template:Convert in 1954 by John Lyman, professor of oceanography at University of North Carolina at Chapel Hill, and Template:Convert in 2014 by the General Bathymetric Chart of the Oceans (GEBCO), and Template:Convert in 2018 by marine geologist Heather Stewart and marine biologist Alan Jamieson. Stewart and Jamieson also reported a maximum depth of Template:Convert in 2019 and Template:Convert in 2021.

File:Atlantic-trench.JPG

Perspective view of the sea floor of the Atlantic Ocean and the Caribbean Sea. The Lesser Antilles are on the lower left side of the view and Florida is on the upper right. The purple sea floor at the center of the view is the Puerto Rico Trench, the deepest part of the Atlantic Ocean.

History

File:USS Milwaukee (CL-5) underway, circa the early 1930s (NH 97979).jpg

Discoverer ship USS Milwaukee (CL-5)

The 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 Template:Convert. On August 19, 1952, the U.S. Fish and Wildlife vessel Theodore N. Gill obtained a reading of Template:Convert at (Template:Coord), virtually identical with the MilwaukeeTemplate:'s reading. By then, the existence of deep water to the Atlantic Ocean side of the Caribbean had been known for more than a century.

One of the area's earliest soundings was obtained June 12, 1852 by Lt. S. P. Lee, U.S. Navy brig Dolphin, with a reading of Template:Convert at (Template:Coord).

Crewed descents

File:Limiting Factor to be prepared for a dive into the Atlantic Ocean.jpg

Deep Submersible Support Vessel DSSV Pressure Drop and DSV Limiting Factor at its stern

In 1964, the French submersible Archimède explored the Puerto Rico Trench to a depth of approximately Template:Convert but did not reach its deepest point.

On 21 December 2018 Victor Vescovo made the first crewed descent to the deepest point of the trench in the Deep-Submergence Vehicle DSV Limiting Factor (a Triton 36000/2 model submersible) and measured a depth of Template:Convert by direct CTD pressure measurements. This made the Limiting Factor the deepest diving operational submersible at the time.

See also

• List of submarine topographical features
• Oceanic trench
• Challenger Deep