The Mariana Trench Marine National Monument consists of 95,216 square miles. The monument consists of submerged lands and waters of the Mariana Archipelago. It includes three units:
Islands Unit - the waters and submerged lands of the three northernmost Mariana Islands
Volcanic Unit - the submerged lands within 1 nautical mile of 21 designated volcanic sites
In the Islands Unit, unique reef habitats support marinebiological communities dependent on basalt rock foundations, unlike those throughout the remainder of the Pacific. These reefs and waters are among the most biologically diverse in the Western Pacific and include the greatest diversity of seamount and hydrothermal vent life yet discovered. They also contain one of the most diverse collections of stony corals in the Western Pacific, including more than 300 species, higher than any other U.S. reef area.
The submerged caldera at Maug is one of only a few known places in the world where photosynthetic and chemosynthetic communities of life coexist. The caldera is some 1.5 miles wide and 820 feet deep, an unusual depth for lagoons. The lava dome in the center of the crater rises to within 65 feet of the surface. Hydrothermal vents at about 475 feet in depth along the northeast side of the dome spew acidic water at scalding temperatures near the coral reef that quickly ascends to the sea surface. Thus, coral reefs and microbial mats are spared much of the impact of these plumes and are growing nearby, complete with thriving tropical fish. As ocean acidification increases across the Earth, this caldera offers scientists an opportunity to look into the future and ensure continuation of coral reef communities. The Mariana Arc of Fire National Wildlife Refuge - an arc of 21 undersea mud volcanoes and thermal vents - supports unusual life forms in some of the harshest conditions imaginable. Here species survive in the midst of hydrothermal vents that produce highly acidic boiling water.
The Champagne hydrothermal vent, found at the Northwest Eifuku submarine volcano produces almost pure liquid carbon dioxide, one of only two known sites in the world.
A pool of liquid sulfur at the Daikoku submarine volcano is unique.
The Challenger Deep, located just outside the Trench Unit, is the deepest point in the Earth's oceans, deeper than the height of Mount Everestabove sea level. It is five times longer than the Grand Canyon and includes some of virtually unexplored underwater terrain. The Sirena Deep, about 6.6 miles beneath the surface, is the deepest point of the Mariana Trench Marine National Monument.
Name of monument
In a White House release the first word is pluralized as Marianas, in another seemingly official source it is named Mariana, and in some news reports it appeared as Marianas Marine National Monument, omitting the word "Trench". In common usage, the trench is alternatively named Marianas Trench or Mariana Trench. The actual text of the proclamation establishing it gives it the official nameMarianas Trench Marine National Monument.
